Light detection device

Abstract

A first light detection device according to an embodiment of the present disclosure comprises: a semiconductor substrate having opposing first and second surfaces, in which a plurality of pixels are arranged in a two-dimensional array and a plurality of photoelectric conversion units adjacent to each other in each of a first direction and a second direction orthogonal to the first direction are formed in an embedded manner in each of the pixels; an inter-pixel isolation part formed in an embedded manner in the semiconductor substrate so as to surround each of the plurality of pixels; and an inter-element isolation part formed an embedded manner in the semiconductor substrate and including, within a pixel, a first isolation part provided between the plurality of photoelectric conversion units adjacent to each other in the first direction and a second isolation part provided between the plurality of photoelectric conversion units adjacent to each other in the first direction, wherein the first isolation part and / or the second isolation part has a gap between itself and the inter-pixel isolation part.

Description

Photodetector

[0001] The present disclosure relates to, for example, a light detection device capable of acquiring imaging information and parallax information.

[0002] For example, Patent Document 1 discloses a solid-state imaging device in which, in a pixel array section in which a plurality of pixels, each having a plurality of photoelectric conversion elements formed for one on-chip lens, are two-dimensionally arranged, at least one of an inter-pixel isolation section and an inter-pixel light-shielding section formed between the pixels is provided with a protrusion, part of which protrudes in a protruding shape toward the center of the pixel, thereby improving the accuracy of phase difference detection.

[0003] [Rule 91 Amendment 12.08.2025] WO 2018-221443

[0004] Incidentally, there is a demand for improved imaging performance in light detection devices capable of acquiring imaging information and parallax information.

[0005] It is desirable to provide a photodetector that can achieve both high imaging performance and phase difference detection performance.

[0006] A first photodetector according to one embodiment of the present disclosure includes a semiconductor substrate having opposing first and second surfaces, in which a plurality of pixels are arranged in a two-dimensional array, and in which a plurality of photoelectric conversion units adjacent to each other in a first direction and a second direction perpendicular to the first direction are embedded for each pixel; inter-pixel isolation units embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and inter-element isolation units embedded in the semiconductor substrate, including a first isolation unit provided between the plurality of photoelectric conversion units adjacent to each other in the first direction and a second isolation unit provided between the plurality of photoelectric conversion units adjacent to each other in the second direction, and at least one of the first isolation unit and the second isolation unit has a gap between itself and the inter-pixel isolation unit.

[0007] In a first photodetector according to an embodiment of the present disclosure, an inter-element isolation portion is provided in a pixel including a plurality of photoelectric conversion units 12 adjacent in a first direction and a second direction and surrounded by an inter-pixel isolation portion, the inter-element isolation portion including a first isolation portion separating the plurality of adjacent photoelectric conversion units in the first direction and a second isolation portion separating the plurality of adjacent photoelectric conversion units in the second direction, and at least one of the first isolation portion and the second isolation portion has a gap between itself and the inter-pixel isolation portion. This facilitates control of the potential of the overflow paths in the first direction and the second direction, compared to a case in which overflow paths in the first direction and the second direction are provided in the center of the pixel.

[0008] A second photodetector according to one embodiment of the present disclosure includes a semiconductor substrate having opposing first and second surfaces, in which a plurality of pixels are arranged in a two-dimensional array, and in which a plurality of photoelectric conversion units adjacent to each other in a first direction and a second direction perpendicular to the first direction are embedded for each pixel; inter-pixel isolation units embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and inter-element isolation units embedded in the semiconductor substrate, including a first isolation unit provided between the plurality of photoelectric conversion units adjacent to each other in the first direction and a second isolation unit provided between the plurality of photoelectric conversion units adjacent to each other in the second direction, in which the first isolation unit has a first bottom within the semiconductor substrate and the second isolation unit has a second bottom within the semiconductor substrate, and the first bottom and the second bottom are formed at different depths within the semiconductor substrate.

[0009] In a second photodetector according to an embodiment of the present disclosure, an inter-element isolation portion is provided in a pixel including a plurality of photoelectric conversion units 12 adjacent in a first direction and a second direction and surrounded by an inter-pixel isolation portion, the inter-element isolation portion separating the adjacent photoelectric conversion units. The inter-element isolation portion includes a first isolation portion separating the adjacent photoelectric conversion units in the first direction and a second isolation portion separating the adjacent photoelectric conversion units in the second direction. The first isolation portion has a first bottom within the semiconductor substrate, and the second isolation portion has a second bottom within the semiconductor substrate, the first bottom and the second bottom being formed at different depths within the semiconductor substrate. This facilitates control of the potential of the overflow paths in the first direction and the second direction, compared to a case in which the overflow paths in the first direction and the second direction are provided in the center of the pixel.

[0010] A third photodetector according to an embodiment of the present disclosure includes a semiconductor substrate having opposing first and second surfaces, in which a plurality of pixels are arranged in a two-dimensional array, and in which a plurality of photoelectric conversion units are embedded for each pixel, the photoelectric conversion units being adjacent to each other in a first direction and a second direction perpendicular to the first direction; an inter-pixel isolation unit embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and an inter-element isolation unit embedded in the semiconductor substrate, the inter-element isolation unit including: a first isolation unit provided between the plurality of photoelectric conversion units adjacent to each other in the first direction and having a first perimeter in a planar view; and a second isolation unit provided between the plurality of photoelectric conversion units adjacent to each other in the second direction and having a second perimeter in a planar view, wherein when the first direction is a phase difference acquisition direction and the second direction is a direction other than the phase difference acquisition direction, the second perimeter is shorter than the first perimeter.

[0011] In a third photodetector according to an embodiment of the present disclosure, a pixel includes a plurality of photoelectric conversion units 12 adjacent in a first direction and a second direction, and the pixel includes a first isolation unit that isolates the adjacent photoelectric conversion units. The inter-element isolation unit includes a first isolation unit that isolates the adjacent photoelectric conversion units in the first direction and a second isolation unit that isolates the adjacent photoelectric conversion units in the second direction. The first isolation unit has a first perimeter in a planar view, and the second isolation unit has a second perimeter in a planar view. When the first direction is the phase difference acquisition direction and the second direction is a direction other than the phase difference acquisition direction, the first perimeter is shorter than the first perimeter. This creates a difference in potential between the overflow paths in the first direction and the second direction.

[0012] A fourth photodetector according to an embodiment of the present disclosure includes a semiconductor substrate having opposing first and second surfaces, a plurality of pixels arranged in a two-dimensional array, and a plurality of photoelectric conversion units embedded in each pixel, the photoelectric conversion units being adjacent to each other in a first direction and a second direction perpendicular to the first direction; inter-pixel isolation units embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and a pair of first protrusions extending from each of a pair of sides of the inter-pixel isolation units facing each other in the second direction to approximately just before the center of the pixel between the plurality of photoelectric conversion units adjacent to each other in the first direction. and an inter-element isolation portion embedded in a semiconductor substrate, the inter-element isolation portion including a first isolation portion consisting of a pair of second protrusions extending from each of a pair of sides of the inter-pixel isolation portion opposing each other in a first direction to approximately just before the center of the pixel between a plurality of adjacent photoelectric conversion portions in a second direction, wherein the pair of first protrusions each have first side surfaces opposing each other in the semiconductor substrate, and the pair of second protrusions each have second side surfaces opposing each other in the semiconductor substrate, and the first side surfaces and the second side surfaces form mutually different angles with the first surface.

[0013] In a fourth photodetector according to an embodiment of the present disclosure, a pixel includes a plurality of photoelectric conversion units 12 adjacent in a first direction and a second direction and surrounded by an inter-pixel isolation unit. The inter-element isolation unit includes a first isolation unit including first protrusions extending from each of a pair of sides of the inter-pixel isolation unit facing in the second direction between the plurality of photoelectric conversion units adjacent in the first direction to approximately just before the center of the pixel, and a second isolation unit including second protrusions extending from each of a pair of sides of the inter-pixel isolation unit facing in the first direction between the plurality of photoelectric conversion units adjacent in the second direction to approximately just before the center of the pixel. The pair of first protrusions have first side surfaces facing each other in the semiconductor substrate, and the pair of second protrusions have second side surfaces facing each other in the semiconductor substrate, and the first side surfaces and the second side surfaces form different angles with respect to the first surface of the semiconductor substrate. This creates a difference in potential between the overflow paths in the first and second directions.

[0014] A fifth photodetector according to an embodiment of the present disclosure includes a semiconductor substrate having opposing first and second surfaces, in which a plurality of pixels are arranged in a two-dimensional array, and in which a plurality of photoelectric conversion units adjacent to each other in at least a first direction are embedded in each pixel; an inter-pixel isolation portion embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and an inter-element isolation portion embedded in the semiconductor substrate, including, within each pixel, a first isolation portion made of a pair of first protrusions extending from each of a pair of sides of the inter-pixel isolation portion opposing each other in a second direction perpendicular to the first direction toward approximately the center of the pixel between the plurality of photoelectric conversion units adjacent to each other in the first direction, wherein the plurality of pixels include a first pixel and a second pixel having detection wavelengths different from each other, the pair of first protrusions having a first gap therebetween, and the pair of first protrusions provided in the first pixel and the second pixel, respectively, differ from each other in at least one of their positions in the first direction within the pixel and the position of the first gap within the pixel.

[0015] In a fifth photodetector according to an embodiment of the present disclosure, in a first pixel and a second pixel having different detection wavelengths, at least one of the positions of the pair of first protrusions provided in each pixel in the first direction and the position of the first gap formed between the pair of first protrusions in the pixel are made different from each other, thereby aligning the outputs of the left and right pixels in response to incident light at the chief ray angle in all pixels arranged in a two-dimensional array.

[0016] FIG. 1 is a plan view schematic diagram illustrating an example of the configuration of a unit pixel of a photodetector according to a first embodiment of the present disclosure. FIG. 2A is a schematic diagram illustrating an example of a cross-sectional configuration of a unit pixel taken along line II' in FIG. 1. FIG. 2B is a schematic diagram illustrating another example of the cross-sectional configuration of a unit pixel taken along line II' in FIG. 1. FIG. 2C is a schematic diagram illustrating another example of the cross-sectional configuration of a unit pixel taken along line II' in FIG. 1. FIG. 3 is a block diagram illustrating the overall configuration of the photodetector shown in FIG. 1. FIG. 4 is an equivalent circuit diagram of a unit pixel shown in FIG. 1. FIG. 5 is a diagram illustrating the potential of an overflow path between elements adjacent in the X-axis direction and the Y-axis direction shown in FIG. 1. FIG. 6A is a schematic cross-sectional view for explaining an example of a method for manufacturing an inter-element isolation portion shown in FIG. 1. FIG. 6B is a schematic cross-sectional view illustrating a process subsequent to FIG. 6A. FIG. 6C is a schematic cross-sectional view illustrating a process subsequent to FIG. 6B. FIG. 6D is a schematic cross-sectional view illustrating a process subsequent to FIG. 6C. FIG. 6E is a schematic cross-sectional view illustrating a process subsequent to FIG. 6D. FIG. 7 is a schematic plan view illustrating an example of the configuration of a unit pixel of a photodetector device as a comparative example. FIG. 8 is a schematic plan view illustrating an example of the configuration of a unit pixel of a photodetector device according to Modification 1 of the present disclosure. FIG. 9A is a schematic cross-sectional view of a unit pixel taken along line A-A' in FIG. 8. FIG. 9B is a schematic cross-sectional view of a unit pixel taken along line B-B' in FIG. 8. FIG. 10 is a schematic plan view illustrating an example of the configuration of a unit pixel of a photodetector device according to Modification 2 of the present disclosure. FIG. 11 is a schematic plan view illustrating an example of the configuration of a unit pixel of a photodetector device according to a second embodiment of the present disclosure. FIG. 12A is a schematic view illustrating an example of the cross-sectional configuration of a unit pixel taken along line II-II' in FIG. 11. FIG. 12B is a schematic view illustrating an example of the cross-sectional configuration of a unit pixel taken along line III-III' in FIG. 11. FIG. 13 is a schematic plan view illustrating an example of the configuration of a unit pixel of a photodetector device according to a third embodiment of the present disclosure. FIG. 14A is a schematic view illustrating an example of the cross-sectional configuration of a unit pixel taken along line IV-IV' in FIG. Fig. 14B is a schematic diagram showing an example of a cross-sectional configuration of a unit pixel taken along line VV' shown in Fig. 13. Fig. 15A is a schematic plan view (A) and a schematic cross-sectional view (B) for explaining an example of a method for manufacturing the inter-element isolation portion shown in Fig. 1. Fig. 15B is a schematic plan view (A) and a schematic cross-sectional view (B) showing a step subsequent to Fig. 15A.FIG. 15C is a schematic plan view (A) and a schematic cross-sectional view (B) illustrating a step subsequent to FIG. 15B. FIG. 15D is a schematic plan view (A) and a schematic cross-sectional view (B) illustrating a step subsequent to FIG. 15C. FIG. 16 is a schematic plan view illustrating an example of the configuration of a unit pixel of a photodetector according to Modification 3 of the present disclosure. FIG. 17A is a schematic cross-sectional view of a unit pixel taken along line VI-VI' shown in FIG. 16. FIG. 17B is a schematic cross-sectional view of a unit pixel taken along line VII-VII' shown in FIG. 16. FIG. 18 is a schematic plan view illustrating an example of the configuration of a unit pixel of a photodetector according to Modification 4 of the present disclosure. FIG. 19A is a schematic cross-sectional view of a unit pixel taken along line VIII-VIII' shown in FIG. 18. FIG. 19B is a schematic cross-sectional view of a unit pixel taken along line IX-IX' shown in FIG. 18. FIG. 20 is a schematic plan view illustrating an example of the configuration of a unit pixel of a photodetector according to Modification 5 of the present disclosure. 21A is a schematic cross-sectional view of a unit pixel taken along line XX' shown in FIG. 20. FIG. 21B is a schematic cross-sectional view of a unit pixel taken along line XI-XI' shown in FIG. 20. FIG. 22A is a schematic cross-sectional view of a unit pixel taken along line XX' shown in FIG. 20. FIG. 22B is a schematic cross-sectional view of a unit pixel taken along line XI-XI' shown in FIG. 20. FIG. 23 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to Modification 6 of the present disclosure. FIG. 24A is a schematic cross-sectional view of a unit pixel taken along line XII-XII' shown in FIG. 23. FIG. 24B is a schematic cross-sectional view of a unit pixel taken along line XIII-XIII' shown in FIG. 23. FIG. 25A is a schematic cross-sectional view of a unit pixel taken along line XII-XII' shown in FIG. 23. FIG. 25B is a schematic cross-sectional view of a unit pixel taken along line XIII-XIII' shown in FIG. 23. Fig. 26A is a schematic plan view showing an example of the configuration of a green pixel (A) and a red pixel and a blue pixel (B) of a photodetector according to a fourth embodiment of the present disclosure. Fig. 26B is a schematic plan view showing an example of the arrangement of green, red, and blue pixels in a pixel array section. Fig. 27 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to a comparative example. Fig. 28 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to a seventh modification of the present disclosure. Fig. 29A is a schematic cross-sectional view of a unit pixel taken along line XIV-XIV' shown in Fig. 28.FIG. 29B is a schematic cross-sectional view of a unit pixel taken along line XV-XV' shown in FIG. 28. FIG. 30 is a schematic plan view illustrating an example of the configuration of a unit pixel of a photodetector according to Modification 8 of the present disclosure. FIG. 31A is a schematic plan view illustrating an example of the configuration of a unit pixel of a photodetector according to Modification 9 of the present disclosure. FIG. 31B is a schematic plan view illustrating another example of the configuration of a unit pixel of a photodetector according to Modification 9 of the present disclosure. FIG. 31C is a schematic plan view illustrating another example of the configuration of a unit pixel of a photodetector according to Modification 9 of the present disclosure. FIG. 32 is a schematic plan view illustrating an example of the arrangement of well contacts in a photodetector according to a comparative example of the present disclosure. FIG. 33 is a schematic plan view illustrating an example of the arrangement of well contacts in a photodetector according to an example of the present disclosure. FIG. 34 is a schematic plan view illustrating an example of the configuration of green, red, and blue pixels of a photodetector according to Modification 10 of the present disclosure. FIG. 35A is a schematic cross-sectional view of a unit pixel taken along line XVI-XVI' shown in FIG. 34. FIG. 35B is a cross-sectional schematic diagram of a unit pixel taken along line XVII-XVII′ in FIG. 34 . FIG. 36A is a plan view schematic diagram illustrating an example of the configuration of a unit pixel of a photodetector according to Modification 11 of the present disclosure. FIG. 36B is a plan view schematic diagram illustrating another example of the configuration of a unit pixel of a photodetector according to Modification 11 of the present disclosure. FIG. 36C is a plan view schematic diagram illustrating another example of the configuration of a unit pixel of a photodetector according to Modification 11 of the present disclosure. FIG. 37 is a plan view schematic diagram illustrating an example of the shapes of a first isolation portion and a second isolation portion at respective positions in a pixel array section of a photodetector according to Modification 12 of the present disclosure. FIG. 38A is a plan view schematic diagram illustrating an example of the shapes of the first isolation portion and the second isolation portion at position B shown in FIG. 37 . FIG. 38B is a plan view schematic diagram illustrating an example of the shapes of the first isolation portion and the second isolation portion at position C shown in FIG. 37 . FIG. 39 is a plan view schematic diagram illustrating an example of the configuration of a unit pixel of a photodetector according to a fifth embodiment of the present disclosure. Fig. 40A is a schematic cross-sectional view showing an example of the configuration of a unit pixel taken along line XVIII-XVIII' shown in Fig. 39. Fig. 40B is a schematic cross-sectional view showing an example of the configuration of a unit pixel taken along line XIX-XIX' shown in Fig. 39. Fig. 41 is a diagram showing the relationship between Si depth and inter-element potential taken along line XVIII-XVIII' and line XIX-XIX' shown in Fig. 39.FIG. 42 is a diagram showing the relationship between the Si depth of the four photoelectric conversion units in the pixel shown in FIG. 39 and the transfer potential to the floating diffusion. FIG. 43A is a schematic cross-sectional view showing another example of the configuration of a unit pixel taken along line XVIII-XVIII' shown in FIG. 39. FIG. 43B is a schematic cross-sectional view showing another example of the configuration of a unit pixel taken along line XIX-XIX' shown in FIG. 39. FIG. 44A is a schematic cross-sectional view showing another example of the configuration of a unit pixel taken along line XVIII-XVIII' shown in FIG. 39. FIG. 44B is a schematic cross-sectional view showing another example of the configuration of a unit pixel taken along line XIX-XIX' shown in FIG. 39. FIG. 45 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to Modification 13 of the present disclosure. FIG. 46 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to Modification 14 of the present disclosure. FIG. 47 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to Modification 15 of the present disclosure. FIG. 48 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to Modification 16 of the present disclosure. FIG. 49 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to Modification 17 of the present disclosure. FIG. 50 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to Modification 18 of the present disclosure. FIG. 51 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to Modification 19 of the present disclosure. FIG. 52A is a schematic cross-sectional view showing an example of the configuration of a unit pixel taken along line XX-XX' shown in FIG. 49. FIG. 52B is a schematic cross-sectional view showing an example of the configuration of a unit pixel taken along line XXI-XX' shown in FIG. 49. FIG. 53 is a block diagram showing an example of the configuration of an electronic device including the photodetector shown in FIG. 1 etc. FIG. 54A is a schematic diagram showing an example of the overall configuration of a photodetection system using the photodetector shown in FIG. 3. FIG. 54B is a diagram showing an example of the circuit configuration of the photodetection system shown in FIG. 54A. FIG. 55 is a block diagram showing an example of the overall configuration of a vehicle control system. Fig. 56 is an explanatory diagram showing an example of the installation positions of the vehicle outside information detection unit and the imaging unit. Fig. 57 is a diagram showing an example of the schematic configuration of an endoscopic surgery system. Fig. 58 is a block diagram showing an example of the functional configuration of a camera head and a CCU.FIG. 59 is a schematic plan view illustrating an example of the shape of a first isolation portion and a second isolation portion at each position in a pixel array section of a photodetector according to a sixth embodiment of the present disclosure. FIG. 60A is a schematic plan view illustrating an example of the shape of a first isolation portion at position A shown in FIG. 59 . FIG. 60B is a schematic plan view illustrating an example of the shape of a first isolation portion at position B1 shown in FIG. 59 . FIG. 60B is a schematic plan view illustrating an example of the shape of a first isolation portion at position C1 shown in FIG. 59 . FIG. 60B is a schematic plan view illustrating an example of the shape of a first isolation portion at position D1 shown in FIG. 59 . FIG. 61 is a schematic cross-sectional view illustrating an example of the configuration of a unit pixel taken along line XXI-XXI′ shown in FIG. 60B . FIG. 62 is a schematic cross-sectional view illustrating another example of the configuration of a unit pixel taken along line XXI-XXI′ shown in FIG. 60B . FIG. 63 is a schematic plan view illustrating an example of the shape of a second isolation portion at position A shown in FIG. 59 of a photodetector according to a twentieth modification of the present disclosure. 63B is a schematic plan view showing an example of the shape of the second separation portion at position B1 shown in FIG. 59 of a photodetector according to Modification 20 of the present disclosure. FIG. 63B is a schematic plan view showing an example of the shape of the second separation portion at position C1 shown in FIG. 59 of a photodetector according to Modification 20 of the present disclosure. FIG. 63B is a schematic plan view showing an example of the shape of the second separation portion at position D1 shown in FIG. 59 of a photodetector according to Modification 20 of the present disclosure. FIG. 64 is a schematic plan view showing an example of the shapes of the first separation portion and the second separation portion at position A shown in FIG. 59 of a photodetector according to Modification 21 of the present disclosure. FIG. 64B is a schematic plan view showing an example of the shapes of the first separation portion and the second separation portion at position B1 shown in FIG. 59 of a photodetector according to Modification 21 of the present disclosure. FIG. 64B is a schematic plan view showing an example of the shapes of the first separation portion and the second separation portion at position C1 shown in FIG. 59 of a photodetector according to Modification 21 of the present disclosure. Fig. 64B is a plan view schematic showing an example of the shapes of the first isolation portion and the second isolation portion at position D1 shown in Fig. 59 of a photodetector according to Modification 21 of the present disclosure. Fig. 65 is a plan view schematic showing an example of the configuration of a unit pixel of a photodetector according to Modification 22 of the present disclosure. Fig. 66 is a cross-sectional view schematic showing an example of the configuration of each unit pixel taken along line XXII-XXII' shown in Fig. 65.FIG. 67 is a schematic plan view showing an example of the configuration of a unit pixel of a photodetector according to Modification 23 of the present disclosure. FIG. 68 is a schematic cross-sectional view showing an example of the configuration of each unit pixel taken along line XXIII-XXIII′ shown in FIG. 67. FIG. 69 is a schematic plan view showing an example of the shapes of the first isolation portion and the second isolation portion on the light incident surface side (A) and the element forming surface side (B) of a unit pixel of a photodetector according to Modification 24 of the present disclosure. FIG. 70 is a schematic cross-sectional view showing an example of the configuration of each unit pixel taken along line XXIV-XXIV′ shown in FIG. 69. FIG. 71 is a schematic plan view showing an example of the shapes of the first isolation portion and the second isolation portion on the light incident surface side (A) and the element forming surface side (B) of a unit pixel of a photodetector according to Modification 25 of the present disclosure. FIG. 72 is a schematic cross-sectional view showing an example of the configuration of each unit pixel taken along line XXV-XXV′ shown in FIG. 71.

[0017] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspects. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, and the like of each component shown in each drawing. The description will be given in the following order. 1. First Embodiment (An example of a photodetector in which an inter-element isolation section that isolates adjacent photoelectric conversion sections in a first direction and a second direction within a pixel has a cross shape that is independent from the inter-pixel isolation section and has different lengths in the first direction and the second direction) 2. Modifications 2-1. Modification 1 (Another example of the configuration of a photodetector) 2-2. Modification 2 (Another example of the configuration of a photodetector) 3. Second Embodiment (An example of a photodetector in which, of the inter-element isolation sections that isolate adjacent photoelectric conversion sections in a pixel in the first direction and the second direction, the inter-element isolation section that extends in the first direction or the second direction is isolated from the inter-pixel isolation section) 4. 3. Third Embodiment (An example of a photodetector in which adjacent photoelectric conversion units in a pixel are separated in the first direction and the second direction by an inter-element separation unit having different depths in the first direction and the second direction) 5. Modifications 5-1. Modification 3 (Another example of a configuration of a photodetector) 5-2. Modification 4 (Another example of a configuration of a photodetector) 5-3. Modification 5 (Another example of a configuration of a photodetector) 5-4. Modification 6 (Another example of a configuration of a photodetector) 6. Fourth Embodiment (An example of a photodetector in which the lengths of multiple protrusions constituting an inter-element separation unit that separates adjacent photoelectric conversion units in a pixel in the first direction and the second direction are different in the phase difference acquisition direction and a direction different from the phase difference acquisition direction) 7. Modifications 7-1. Modification 7 (Another example of a configuration of a photodetector) 7-2. Modification 8 (Another example of a configuration of a photodetector) 7-3. Modification 9 (Another example of a configuration of a photodetector) 7-4. 7. Modification 10 (Another example of the configuration of the photodetector) 7-5. Modification 11 (Another example of the configuration of the photodetector) 7-6. Modification 12 (Another example of the configuration of the photodetector) 8. Fifth embodiment (An example of a photodetector in which the side surfaces of a plurality of protrusions constituting an inter-element isolation section that isolates adjacent photoelectric conversion sections in the first direction and the second direction in a pixel have angles different from each other) 9. Modifications9-1. Modification 13 (Another Example of the Configuration of the Photodetector) 9-2. Modification 14 (Another Example of the Configuration of the Photodetector) 9-3. Modification 15 (Another Example of the Configuration of the Photodetector) 9-4. Modification 16 (Another Example of the Configuration of the Photodetector) 9-5. Modification 17 (Another Example of the Configuration of the Photodetector) 9-6. Modification 18 (Another Example of the Configuration of the Photodetector) 9-7. Modification 19 (Another Example of the Configuration of the Photodetector) 10. Sixth Embodiment (Example of a photodetector in which the positions of the multiple protrusions constituting the inter-element isolation unit and the gaps between opposing protrusions differ for each position within the pixel array unit and for each RGB pixel) 11. Modifications 11-1. Modification 20 (Another Example of the Configuration of the Photodetector) 11-2. Modification 21 (Another Example of the Configuration of the Photodetector) 11-3. Modification 22 (Another Example of the Configuration of the Photodetector) 11-4. Modification 23 (another example of the configuration of the photodetector) 11-5. Modification 24 (another example of the configuration of the photodetector) 11-6. Modification 25 (another example of the configuration of the photodetector) 12. Application example 13. Application example

[0018] 1. First Embodiment FIG. 1 schematically illustrates an example of a planar configuration of a unit pixel P constituting a photodetector (photodetector 1) according to a first embodiment of the present disclosure. FIGS. 2A to 2C schematically illustrate an example of a cross-sectional configuration of the unit pixel P shown in FIG. 1 , taken along line II'. The photodetector 1 is, for example, a complementary metal oxide semiconductor (CMOS) image sensor used in electronic devices such as digital still cameras and video cameras, and has a pixel section (pixel array section 100A) in which a plurality of pixels (unit pixels P) are two-dimensionally arranged in a matrix as an imaging area. The photodetector 1 is, for example, a so-called back-illuminated photodetector in this CMOS image sensor or the like.

[0019] The photodetector 1 has a configuration in which a plurality of pixels (unit pixels P) capable of simultaneously acquiring imaging information and parallax information (phase difference information) are arranged in a matrix in a pixel array section 100A. Each unit pixel P has a plurality of photoelectric conversion units 12 embedded in a semiconductor substrate 11 and adjacent to each other in the X-axis direction (row direction) and the Y-axis direction (column direction). The unit pixels P are surrounded by an inter-pixel isolation section 13 that separates adjacent unit pixels P in the pixel array section 100A. Each unit pixel P further has an inter-element isolation section 14 including a first isolation section 14A provided between the plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction and a second isolation section 14B provided between the plurality of photoelectric conversion units 12 adjacent to each other in the Y-axis direction. The first isolation section 14A and the second isolation section 14B have gaps G1 and G2 of different lengths between them and the inter-pixel isolation section 13.

[0020] Here, the semiconductor substrate 11 corresponds to a specific example of a "semiconductor substrate" according to an embodiment of the present disclosure. The photoelectric conversion section 12 corresponds to a specific example of a "photoelectric conversion section" according to an embodiment of the present disclosure. The inter-pixel isolation section 13 corresponds to a specific example of an "inter-pixel isolation section" according to an embodiment of the present disclosure. The inter-element isolation section 14 corresponds to a specific example of an "inter-element isolation section" according to an embodiment of the present disclosure. The first isolation section 14A corresponds to a specific example of a "first isolation section" according to an embodiment of the present disclosure, and the gap G1 corresponds to a specific example of a "first gap" according to an embodiment of the present disclosure. The second isolation section 14B corresponds to a specific example of a "second isolation section" according to an embodiment of the present disclosure, and the gap G2 corresponds to a specific example of a "second gap" according to an embodiment of the present disclosure. The X-axis direction corresponds to a specific example of a "first direction" according to an embodiment of the present disclosure, and the Y-axis direction corresponds to a specific example of a "second direction" according to an embodiment of the present disclosure.

[0021] 3 shows an example of the overall configuration of the photodetector 1. As described above, the photodetector 1 is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and has a pixel array section 100A as an imaging area in which a plurality of unit pixels P are two-dimensionally arranged in a matrix.

[0022] The photodetector 1 captures incident light (image light) from a subject via an optical lens system (not shown), converts the amount of incident light imaged on an imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs the electrical signal as a pixel signal. The photodetector 1 has a pixel array section 100A as an imaging area on a semiconductor substrate 11, and also has, in a peripheral region of the pixel array section 100A, for example, a vertical drive circuit 181, a column signal processing circuit 182, a horizontal drive circuit 183, an output circuit 184, a control circuit 185, and input / output terminals 186.

[0023] The pixel array unit 100A has, for example, a plurality of unit pixels P arranged two-dimensionally in a matrix. The plurality of unit pixels P serve as both imaging pixels and image plane phase difference pixels. The imaging pixels photoelectrically convert an object image formed by the imaging lens in a photodiode PD to generate a signal for generating an image. The image plane phase difference pixels divide the pupil region of the imaging lens and photoelectrically convert the object image from the divided pupil region to generate a signal for phase difference detection.

[0024] In the unit pixel P, for example, a pixel drive line Lread (specifically, a row selection line and a reset control line) is wired for each pixel row, and a vertical signal line Lsig is wired for each pixel column. The pixel drive line Lread transmits drive signals for reading signals from the pixels. One end of the pixel drive line Lread is connected to an output terminal of the vertical drive circuit 181 corresponding to each row.

[0025] The vertical drive circuit 181 is a pixel drive unit that includes a shift register, an address decoder, etc., and drives each unit pixel P of the pixel array unit 100A, for example, row by row. Signals output from each unit pixel P of a pixel row selected and scanned by the vertical drive circuit 181 are supplied to a column signal processing circuit 182 through each vertical signal line Lsig. The column signal processing circuit 182 is configured with an amplifier, a horizontal selection switch, etc., provided for each vertical signal line Lsig.

[0026] The horizontal drive circuit 183 is configured with a shift register, an address decoder, etc., and scans and sequentially drives each horizontal selection switch of the column signal processing circuit 182. By selective scanning by this horizontal drive circuit 183, signals of each pixel transmitted through each vertical signal line Lsig are output in sequence to a horizontal signal line 191 and transmitted to the outside of the semiconductor substrate 11 through the horizontal signal line 191.

[0027] The output circuit 184 processes and outputs signals sequentially supplied from each of the column signal processing circuits 182 via the horizontal signal line 191. The output circuit 184 may perform only buffering, or may perform black level adjustment, column variation correction, various digital signal processing, and the like, for example.

[0028] The circuit portion consisting of the vertical drive circuit 181, column signal processing circuit 182, horizontal drive circuit 183, horizontal signal line 191, and output circuit 184 may be formed directly on the semiconductor substrate 11, or may be disposed on an external control IC. Furthermore, these circuit portions may be formed on another substrate connected by a cable or the like.

[0029] The control circuit 185 receives a clock and data instructing an operation mode from outside the semiconductor substrate 11, and outputs data such as internal information of the photodetector 1. The control circuit 185 further has a timing generator that generates various timing signals, and controls the driving of peripheral circuits such as the vertical drive circuit 181, column signal processing circuit 182, and horizontal drive circuit 183 based on the various timing signals generated by the timing generator.

[0030] The input / output terminal 186 is used to exchange signals with the outside.

[0031] [Circuit Configuration of Unit Pixel] Fig. 4 shows an example of the readout circuit 310 of the unit pixel P shown in Fig. 1. As shown in Fig. 1, the unit pixel P has four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns as the multiple photoelectric conversion units 12. As shown in Fig. 4, the unit pixel P has the four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4, four transfer transistors TR1, TR2, TR3, and TR4, and, for example, a floating diffusion FD provided for each unit pixel P, a reset transistor RST, an amplification transistor AMP, and a selection transistor SEL.

[0032] The photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 are each a photodiode (PD). The photoelectric conversion unit 12-1 has an anode connected to a ground voltage line and a cathode connected to the source of the transfer transistor TR1. The photoelectric conversion unit 12-2, like the photoelectric conversion unit 12-1, has an anode connected to a ground voltage line and a cathode connected to the source of the transfer transistor TR2. The photoelectric conversion unit 12-3, like the photoelectric conversion unit 12-1, has an anode connected to a ground voltage line and a cathode connected to the source of the transfer transistor TR3. The photoelectric conversion unit 12-4, like the photoelectric conversion unit 12-1, has an anode connected to a ground voltage line and a cathode connected to the source of the transfer transistor TR4.

[0033] The transfer transistor TR1 is connected between the photoelectric conversion unit 12-1 and the floating diffusion FD. The transfer transistor TR2 is connected between the photoelectric conversion unit 12-2 and the floating diffusion FD. The transfer transistor TR3 is connected between the photoelectric conversion unit 12-3 and the floating diffusion FD. The transfer transistor TR4 is connected between the photoelectric conversion unit 12-4 and the floating diffusion FD. A drive signal TRsig is applied to the gate electrodes of the transfer transistors TR1, TR2, TR3, and TR4. When this drive signal TRsig becomes active, the transfer gates of the transfer transistors TR1, TR2, TR3, and TR4 become conductive, and the signal charges accumulated in the photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 are transferred to the floating diffusion FD via the transfer transistors TR1, TR2, TR3, and TR4.

[0034] The floating diffusion FD is connected between the transfer transistors TR1, TR2, TR3, and TR4 and the amplification transistor AMP. The floating diffusion FD converts the signal charges transferred by the transfer transistors TR1, TR2, TR3, and TR4 into voltage signals and outputs the voltage signals to the amplification transistor AMP.

[0035] The reset transistor RST is connected between the floating diffusion FD and the power supply. A drive signal RSTsig is applied to the gate electrode of the reset transistor RST. When this drive signal RSTsig becomes active, the reset gate of the reset transistor RST becomes conductive, and the potential of the floating diffusion FD is reset to the level of the power supply.

[0036] The amplifier transistor AMP has its gate electrode connected to the floating diffusion FD and its drain electrode connected to a power supply, and serves as an input section of a readout circuit 310 for a voltage signal held by the floating diffusion FD, a so-called source follower circuit. That is, the amplifier transistor AMP has its source electrode connected to the vertical signal line Lsig via the select transistor SEL, and thereby constitutes a source follower circuit together with a constant current source connected to one end of the vertical signal line Lsig.

[0037] The selection transistor SEL is connected between the source electrode of the amplification transistor AMP and the vertical signal line Lsig. A drive signal SELsig is applied to the gate electrode of the selection transistor SEL. When this drive signal SELsig is activated, the selection transistor SEL is turned on and the unit pixel P is selected. As a result, a read signal (pixel signal) output from the amplification transistor AMP is output to the vertical signal line Lsig via the selection transistor SEL.

[0038] In the unit pixel P, for example, the signal charges generated in the photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 are read out. The signal charges read out from the photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 are output to, for example, a phase difference calculation block of an external signal processing unit, thereby obtaining a signal for phase difference autofocus. Furthermore, the signal charges read out from the photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 are added together in the floating diffusion FD, and the resulting sum is output to, for example, an imaging block of an external signal processing unit, thereby obtaining a pixel signal based on the total charge of the photoelectric conversion units 12-1, 12-2, 12-3, and 12-4.

[0039] [Configuration of Unit Pixel] As described above, the photodetector 1 is, for example, a back-illuminated photodetector. The unit pixels P are two-dimensionally arranged in a matrix in the pixel array 100A and each have a configuration in which, for example, a light receiving section 10, a light collecting section 20 provided on a light incident side S1 of the light receiving section 10, and a multilayer wiring layer 30 provided on the side opposite to the light incident side S1 of the light receiving section 10 are stacked.

[0040] The light receiving unit 10 includes a semiconductor substrate 11 having a first surface 11S1 and a second surface 11S2 facing each other, and a plurality of photoelectric conversion units 12 embedded in the semiconductor substrate 11. The semiconductor substrate 11 is, for example, a silicon (Si) substrate, and has a p-well in a predetermined region. The photoelectric conversion units 12 are, for example, PIN (Positive Intrinsic Negative) photodiodes (PD), and have a p-n junction in a predetermined region of the semiconductor substrate 11. As described above, four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns are embedded in the unit pixel P.

[0041] The light receiving section 10 further has an inter-pixel isolation section 13 and an inter-element isolation section 14. P-type diffusion regions 121 are formed in the semiconductor substrate 11 on the side surfaces of the inter-pixel isolation section 13 and the inter-element isolation section 14. Furthermore, n-type diffusion regions 122 that constitute overflow paths OFP1 and OFP2 (described later) are formed in, for example, a first surface 11S1 of the semiconductor substrate 11 (see, for example, FIGS. 9A and 9B ).

[0042] The inter-pixel isolation portions 13 are intended to physically and electrically isolate adjacent unit pixels P, and are embedded in the semiconductor substrate 11 so as to surround each of the unit pixels P arranged in a two-dimensional array in the pixel array section 100A. In other words, the inter-pixel isolation portions 13 are embedded in the semiconductor substrate 11 so as to isolate adjacent unit pixels P, and are provided in, for example, a lattice pattern in the pixel array section 100A. In a cross-sectional view, the inter-pixel isolation portions 13 extend, for example, from the second surface 11S2 side of the semiconductor substrate 11 toward the first surface 11S1 side.

[0043] The inter-element isolation portion 14 physically and electrically isolates adjacent photoelectric conversion portions 12 within a pixel to prevent the outputs of adjacent phase difference detection elements (photoelectric conversion portions 12) from mixing during phase difference detection. The inter-element isolation portion 14 includes, for example, a first isolation portion 14A extending from approximately the center of the pixel in the Y-axis direction and a second isolation portion 14B similarly extending from approximately the center of the pixel in the X-axis direction. In other words, as shown in FIG. 1, the inter-element isolation portion 14 has a generally cross shape in a plan view that intersects with each other at approximately the center of the pixel so as to isolate four photoelectric conversion portions 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns in the X-axis direction (row direction) and the Y-axis direction (column direction) within the pixel. Specifically, the inter-element isolation portion 14 has a first isolation portion 14A that extends in the Y-axis direction and isolates the photoelectric conversion portion 12-1 and the photoelectric conversion portion 12-2 that are adjacent in the X-axis direction and the photoelectric conversion portion 12-3 and the photoelectric conversion portion 12-4 that are adjacent in the Y-axis direction, and a second isolation portion 14B that extends in the X-axis direction and isolates the photoelectric conversion portion 12-1 and the photoelectric conversion portion 12-4 that are adjacent in the Y-axis direction and the photoelectric conversion portion 12-2 and the photoelectric conversion portion 12-3 that are adjacent in the Y-axis direction. In the photodetector 1, by providing the inter-element isolation portion 14 that isolates the four photoelectric conversion portions 12-1, 12-2, 12-3, and 12-4 that are arranged in two rows and two columns from each other, phase difference information in all directions can be obtained in one unit pixel P.

[0044] In the photodetector 1 of this embodiment, the inter-pixel isolation portion 13 and the inter-element isolation portion 14 are independent of each other. In other words, there is a gap between the inter-pixel isolation portion 13 and both ends of the first isolation portion 14A extending in the Y-axis direction, and there is a gap between the inter-pixel isolation portion 13 and both ends of the second isolation portion 14B extending in the X-axis direction.

[0045] Furthermore, the lengths in the extension direction (longitudinal direction) of the first isolation portion 14A and the second isolation portion 14B are different from each other. For example, the longitudinal length of the first isolation portion 14A is longer than the longitudinal length of the second isolation portion 14B, and the gap G1 between both ends of the first isolation portion 14A and the inter-pixel isolation portion 13 is narrower than the gap G2 between both ends of the second isolation portion 14B and the inter-pixel isolation portion 13.

[0046] 5 shows the potential of an overflow path OFP1 between photoelectric conversion units 12-1 and 12-2 (or between photoelectric conversion units 12-3 and 12-4) that are adjacent in the X-axis direction, and an overflow path OFP2 between photoelectric conversion units 12-1 and 12-4 that are adjacent in the Y-axis direction and between photoelectric conversion units 12-2 and 12-3. An "overflow path" refers to a path that transfers saturated signal charges (saturated charges) between multiple phase difference detection elements (here, four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4). During normal imaging, when the charge in one of the four photoelectric conversion units in a pixel (for example, photoelectric conversion unit 12-1) approaches saturation, the charge is transferred to another photoelectric conversion unit (for example, photoelectric conversion unit 12-4) via the overflow path, thereby preventing saturation of the photoelectric conversion unit 12-1. In this way, by providing the overflow path, the linearity of the pixel signal output from the unit pixel P can be ensured, and degradation of the captured image can be prevented.

[0047] In the photodetector 1, an overflow path OFP1 is formed between both ends of the inter-pixel isolation portion 13 and the first isolation portion 14A, and an overflow path OFP2 is formed between both ends of the inter-pixel isolation portion 13 and the second isolation portion 14B. The overflow path OFP1 and the overflow path OFP2 are configured, for example, by an n-type diffusion region 122 formed on the first surface 11S1 of the semiconductor substrate 11 (see, for example, FIGS. 9A and 9B ). The overflow path OFP1 formed in the gap G1, which is narrower than the inter-pixel isolation portion 13, requires a higher potential for transferring saturated charges than the overflow path OFP2 formed in the gap G2, which is wider than the inter-pixel isolation portion 13. Although details will be described later, in this embodiment, overflow paths OFP1 between photoelectric conversion units 12-1 and 12-2 that are adjacent in the X-axis direction and between photoelectric conversion units 12-3 and 12-4, and overflow paths OFP2 between photoelectric conversion units 12-1 and 12-4 that are adjacent in the Y-axis direction and between photoelectric conversion units 12-2 and 12-3 are formed independently. This makes it possible to easily control the potentials of overflow paths OFP1 and OFP2 in the X-axis direction and the Y-axis direction, respectively.

[0048] The difference between the gap G1 and the gap G2 is preferably, for example, 50 nm or more and 100 nm or less. This allows a sufficient difference to be provided between the potential of the overflow path OFP1 and the potential of the overflow path OFP2. Here, "sufficient difference" means that a potential difference is formed that allows operation without being affected by variations between pixels during mass production. The same applies hereinafter.

[0049] The inter-pixel isolation portion 13 and the inter-element isolation portion 14 are formed by trenches 15 that penetrate between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11 and have a so-called FTI (Full Trench Isolation) structure.

[0050] As shown in FIG. 2A , a light-transmitting electrode film 153 is embedded in the groove 15. Between the electrode film 153 and the semiconductor substrate 11, i.e., between the side and bottom surfaces of the groove 15 and the electrode film 153 embedded in the groove 15, and between the first surface 11S1 of the semiconductor substrate 11 and the electrode film 153 extending thereover, a film having a fixed charge (fixed charge film 151) and a silicon oxide (SiO ) film 152 are formed in this order from the semiconductor substrate 11 side. The fixed charge film 151 is made of, for example, a mixed film of aluminum oxide (Al O ) and tantalum oxide (Ta O ) or a mixed film of Al O and hafnium oxide (Hf O ). A voltage application unit 41 is connected to the electrode film 153, allowing desired voltages to be applied to the inter-pixel isolation portion 13 and the inter-element isolation portion 14, respectively. This allows the potentials of the overflow path OFP1 and the overflow path OFP2 to be controlled arbitrarily.

[0051] As shown in FIG. 2B , the trenches 15 may be filled with a polysilicon film 154 doped with an impurity such as boron (B). In the photodetector 1 shown in FIG. 2B , the polysilicon films 154 filled in the trenches 15 that form the inter-pixel isolation portion 13 and the inter-element isolation portion 14 are independent of each other. In this configuration, when voltages are applied to the inter-pixel isolation portion 13 and the inter-element isolation portion 14, separate electrodes are formed for each. A fixed charge film 151, for example, is formed on the second surface 11S2 of the semiconductor substrate 11.

[0052] When it is not necessary to apply a voltage to the inter-pixel isolation portion 13 and the inter-element isolation portion 14, an insulating film may be embedded in the groove 15. As an example, as shown in Fig. 2C, after a fixed charge film 151 is formed on the side and bottom surfaces of the groove 15 and on the second surface 11S2 of the semiconductor substrate 11, a SiO film 152 may be embedded in the groove 15 from the second surface 11S2 side of the semiconductor substrate 11.

[0053] 2A to 2C show an example in which the inter-pixel isolation portion 13 and the inter-element isolation portion 14 are formed by trenches 15 having an FTI structure, but the present invention is not limited to this. The inter-pixel isolation portion 13 and the inter-element isolation portion 14 may be formed by trenches having an STI (Shallow Trench Isolation) structure with their bottom surfaces inside the semiconductor substrate 11. The trenches having the STI structure may be formed from the first surface 11S1 side of the semiconductor substrate 11, or may be formed from the second surface 11S2 side of the semiconductor substrate 11.

[0054] The light collecting section 20 is provided on the light incident side S1 of the light receiving section 10 and includes, for example, a protective layer 21, a light blocking film 22, a partition wall 23, a color filter layer 24, and a lens layer 25.

[0055] The protective layer 21 serves to protect the light incident side S1 of the light receiving unit 10 and to planarize the surface. The protective layer 21 is formed using, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0056] The light-shielding film 22 is intended to prevent light obliquely incident on the color filter layer 24 from leaking into adjacent unit pixels P that detect light of different wavelengths. The light-shielding film 22 is provided, for example, above the inter-pixel isolation portion 13 and above the inter-element isolation portion 14. For example, the light-shielding film 22 is provided between adjacent unit pixels P and between adjacent photoelectric conversion portions 12 within a pixel, and is provided, for example, in a grid pattern in plan view.

[0057] Examples of materials that can be used to form the light-shielding film 22 include materials with light-shielding properties. Specific examples include tungsten (W), silver (Ag), copper (Cu), titanium (Ti), aluminum (Al), and alloys thereof. Other examples include metal compounds such as TiN. The light-shielding film 22 may be formed as a single layer film or a multilayer film.

[0058] The partitions 23 are provided to physically separate the color filter layers 24 of different colors provided for each unit pixel P. The partitions 23 are provided, for example, on the light-shielding film 22. That is, like the light-shielding film 22, the partitions 23 are provided between adjacent unit pixels P and between adjacent photoelectric conversion units 12 within a pixel, and are provided, for example, in a grid pattern in plan view. Note that, as described above, it is sufficient for the partitions 23 to be provided between the color filter layers 24 of different colors provided for each unit pixel P, and therefore the partitions 23 above the inter-element isolation unit 14 may be omitted.

[0059] The partition wall 23 is formed of, for example, a single layer film made of one of silicon oxide (SiO), tetraethoxysilane (TEOS), silicon nitride (SiN), silicon oxynitride (SiON), etc., or a laminated film made of two or more of these materials.

[0060] The color filter layer 24 selectively transmits light of a predetermined wavelength. The color filter layer 24 has, for example, a red filter 24R that selectively transmits red light (R), a green filter 24G that selectively transmits green light (G), and a blue filter 24B that selectively transmits blue light (B) (see, for example, FIG. 26B ). Alternatively, the color filter layer 24 may have filters that selectively transmit cyan, magenta, and yellow, respectively.

[0061] Each color filter 24R, 24G, and 24B is provided for each unit pixel P. For example, as shown in FIG. 26B , in four unit pixels P arranged in two rows and two columns, two green filters 24G are arranged diagonally, and one red filter 24R and one blue filter 24B are arranged on each orthogonal diagonal. The unit pixels (red pixel Pr, green pixel Pg, and blue pixel Pb) provided with each color filter detect the corresponding color light. That is, in the pixel array section 100A, the unit pixels (red pixel Pr, green pixel Pg, and blue pixel Pb) that detect red light (R), green light (G), and blue light (B), respectively, are arranged in a Bayer pattern.

[0062] The color filter layer 24 can be formed using, for example, a pigment or a dye. The thickness of the color filter layer 24 may be different for each color, taking into consideration the color reproducibility and sensor sensitivity of the spectral distribution. In black and white pixels, a layer made of a transparent material can be considered as the color filter layer 24. In infrared pixels, a layer made of a material that selectively transmits infrared light can be considered as the color filter layer 24.

[0063] The lens layer 25 is provided, for example, to cover the entire surface of the pixel array unit 100A and has multiple on-chip lenses 25L on its surface. The on-chip lenses 25L focus light incident from above toward the first surface 11S1 of the semiconductor substrate 11, which serves as the light-receiving surface, and are provided for each unit pixel P as shown in FIG. 1 . The lens layer 25 is formed, for example, using a high refractive index material, specifically, an inorganic material such as silicon nitride (SiN). Alternatively, the lens layer 25 may be formed using a high refractive index organic material such as an episulfide resin, a titanium compound, or a resin thereof. The shape of the on-chip lenses 25L is not particularly limited, and various lens shapes such as a hemispherical shape or a semi-cylindrical shape may be employed.

[0064] The multilayer wiring layer 30 is provided on the opposite side of the light receiving section 10 from the light incident side S1. The multilayer wiring layer 30 has, for example, a configuration in which a plurality of wiring layers 31, 32, and 33 are stacked with an interlayer insulating layer 34 interposed therebetween. In the multilayer wiring layer 30, for example, in addition to the readout circuit 310 described above, a vertical drive circuit 181, a column signal processing circuit 182, a horizontal drive circuit 183, an output circuit 184, a control circuit 185, an input / output terminal 186, and the like are formed.

[0065] The wiring layers 31, 32, and 33 are formed using, for example, aluminum (Al), copper (Cu), tungsten (W), etc. Alternatively, the wiring layers 31, 32, and 33 may be formed using polysilicon (Poly-Si).

[0066] The interlayer insulating layer 34 is formed of, for example, a single layer film made of one of silicon oxide (SiO), tetraethoxysilane (TEOS), silicon nitride (SiN), silicon oxynitride (SiON), etc., or a laminated film made of two or more of these materials.

[0067] [Method for Manufacturing Photodetector] FIGS. 6A to 6E show an example of a method for manufacturing the photodetector 1 shown in FIG.

[0068] First, as shown in FIG. 6A, a gate insulating film 34A and an SiO film 141 are formed in this order on the first surface 11S1 side of the semiconductor substrate 11, and then a groove 15 is formed between adjacent photoelectric conversion units 12 by photolithography and etching.

[0069] Next, although not shown, p-type impurities (e.g., boron (B)) are diffused into the semiconductor substrate 11 from the side and bottom surfaces of the trench 15 by, for example, solid-phase diffusion or plasma doping to form p-type diffusion regions 121 (see, for example, FIGS. 9A and 9B ). Subsequently, as shown in FIG. 6B , a SiO film 141 is formed on the side and bottom surfaces of the trench 15 by, for example, atomic layer deposition (ALD), and then a polysilicon film 142 is buried by chemical vapor deposition (CVD) to temporarily fill the trench 15.

[0070] Next, as shown in FIG. 6C, after forming the multi-layer wiring layer 30 including the gate electrode 31G and the like, the logic substrate 40 is bonded onto the multi-layer wiring layer 30.

[0071] 6D , the semiconductor substrate 11 is inverted and thinned by, for example, chemical mechanical polishing (CMP) to expose the trenches 15. Next, the polysilicon film 142 embedded in the trenches 15 is removed, and the SiO film 141 formed on the side surfaces of the trenches 15 is peeled off.

[0072] 6E, a fixed charge film 151 and a SiO film 152 are sequentially formed on the side and bottom surfaces of the grooves 15 and on the first surface 11S1 of the semiconductor substrate 11 using, for example, ALD. Next, an electrode film 153 is formed using, for example, ALD to fill the grooves 15. Thereafter, a protective layer 21, a light-shielding film 22, a partition wall 23, and a color filter layer 24 are sequentially formed on the electrode film 153, and then a lens layer 25 is bonded to the electrode film 153. This completes the photodetector 1 shown in FIG.

[0073] [Functions and Effects] In the photodetector 1 according to the present embodiment, unit pixels P each include a plurality of photoelectric conversion units 12 adjacent in the X-axis direction (row direction) and the Y-axis direction (column direction) and are embedded in the semiconductor substrate 11. The unit pixels P each include an inter-element isolation unit 14 that isolates the plurality of adjacent photoelectric conversion units 12 within the pixel and is embedded in the semiconductor substrate 11, similar to the inter-pixel isolation unit 13. The inter-element isolation unit 14 includes a first isolation unit 14A provided between the plurality of photoelectric conversion units 12 adjacent in the X-axis direction and a second isolation unit 14B provided between the plurality of photoelectric conversion units 12 adjacent in the Y-axis direction within the pixel. The first isolation unit 14A and the second isolation unit 14B have gaps G1 and G2 of different lengths between them and the inter-pixel isolation unit 13. This allows for easy control of the potentials of the overflow paths OFP1 and OFP2 formed in the X-axis direction and the Y-axis direction. This will be explained below.

[0074] In recent years, semiconductor imaging devices (photodetection devices) having a focus detection function using a phase difference detection method have become widespread. An example of such a photodetection device is the photodetection device 1000A shown in FIG. 7 . In the photodetection device 1000A, a unit pixel P is surrounded by an inter-pixel isolation portion 1013. The unit pixel P includes four photodiodes PD1, PD2, PD3, and PD4 arranged in two rows and two columns. These four photodiodes PD1, PD2, PD3, and PD4 are separated from adjacent photodiodes PD1, PD2, PD3, and PD4 in the row direction (X-axis direction) and column direction (Y-axis direction) by inter-element isolation portions 1014 formed of protrusions 1014A and 1014B protruding from the inter-pixel isolation portion 1013 toward the center of the pixel. This allows a single unit pixel P to acquire phase difference information in all directions.

[0075] However, in the photodetector 1000A, the overflow paths OFP1 between the photodiodes PD1 and PD2 adjacent to each other in the X-axis direction and between the photodiodes PD3 and PD4, and the overflow paths OFP2 between the photodiodes PD1 and PD4 adjacent to each other in the Y-axis direction and between the photodiodes PD2 and PD4, are formed in a concentrated manner at approximately the center of the pixel as shown in FIG.

[0076] In photodetector 1000A, the potential of each of overflow paths OFP1 and OFP2 is controlled by changing the protrusion amount of protrusions 1014A and 1014B, but it is difficult to control the protrusion amount of protrusions 1014A and 1014B due to errors in forming groove 15 and variations in the impurity concentration of p-type diffusion regions (not shown) formed on the side and bottom surfaces of groove 15. In other words, the potential of overflow paths OFP1 and OFP2 is easily affected by variations in the manufacturing process of protrusions 1014A and 1014B, which poses a problem of high difficulty in potential design.

[0077] In contrast, in the present embodiment, an inter-element isolation portion 14 consisting of a first isolation portion 14A and a second isolation portion 14B having a generally cross shape that intersect at approximately the center of the pixel isolates adjacent photoelectric conversion portions 12-1, 12-2, 12-3, and 12-4 in the X-axis direction and the Y-axis direction within the pixel. The first isolation portion 14A extends in the Y-axis direction and isolates adjacent photoelectric conversion portions 12-1 and 12-2 and adjacent photoelectric conversion portions 12-3 and 12-4 in the X-axis direction. The second isolation portion 14B extends in the X-axis direction and isolates adjacent photoelectric conversion portions 12-1 and 12-4 and adjacent photoelectric conversion portions 12-2 and 12-3 in the Y-axis direction. Gaps G1 and G2 of different lengths are provided between both ends of each of first isolation portion 14A and second isolation portion 14B and inter-pixel isolation portion 13, and overflow paths OFP1 and OFP2 are formed in these gaps G1 and G2. As a result, compared to photodetector device 1000A in which overflow paths OFP1 and OFP2 are formed in a concentrated manner substantially at the center of the pixel, even if variations occur in the manufacturing process for inter-element isolation portion 14, a difference can easily be created between the potential of overflow path OFP1 and the potential of overflow path OFP2.

[0078] As described above, in the photodetector 1 of this embodiment, it is possible to easily control the potentials of the overflow paths OFP1 and OFP2 formed in the X-axis direction and the Y-axis direction, thereby achieving both high imaging performance and phase difference detection performance.

[0079] Furthermore, in the photodetector 1 of this embodiment, the inter-element isolation portion 14 is provided approximately in the center of the pixel, thereby enabling optical isolation performance to be improved compared to the photodetector 1000A described above.

[0080] Next, second to sixth embodiments and modified examples 1 to 25 of the present disclosure, as well as application examples and applied examples, will be described. In the following, components similar to those in the first embodiment will be assigned the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0081] 8 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 1A) according to Modification 1 of the present disclosure. FIG. 9A is a diagram illustrating an example of a cross-sectional configuration corresponding to line A-A' shown in FIG. 8. FIG. 9B is a diagram illustrating an example of a cross-sectional configuration corresponding to line B-B' shown in FIG. 8. Like the photodetector 1 of the first embodiment, the photodetector 1A is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0082] In the first embodiment, an example was shown in which an electrode film 153 and an impurity-doped polysilicon film 154 are embedded in the groove 15 that constitutes the inter-element isolation portion 14, and a voltage is applied to the electrode film 153 and the polysilicon film 154 to control the potential of the overflow path OFP1 and the overflow path OFP2, but the present invention is not limited to this. In the photodetector 1A of this modified example, a transfer gate 31G1 is provided on the inter-pixel isolation portion 13 on an extension of the first isolation portion 14A, and a transfer gate 31G2 is provided on the inter-pixel isolation portion 13 on an extension of the second isolation portion 14B. In the photodetector 1A, the potential of the overflow path OFP1 and the overflow path OFP2 is controlled by applying a voltage to the transfer gates 31G1 and 31G2.

[0083] 9A and 9B illustrate a cross-sectional configuration in the vicinity of transfer gates 31G1 and 31G2 provided on the inter-pixel isolation portion 13. As an example, FIG. 9A schematically illustrates a cross-sectional configuration in the Y-axis direction in the vicinity of transfer gate 31G2 provided on inter-pixel isolation portion 13 on an extension of second isolation portion 14B. As an example, FIG. 9B schematically illustrates a cross-sectional configuration in the X-axis direction in the vicinity of transfer gate 31G2 provided on inter-pixel isolation portion 13 on an extension of second isolation portion 14B (specifically, on STI 13A forming part of inter-pixel isolation portion 13). Transfer gate 31G2 is provided across adjacent unit pixels P with inter-pixel isolation portion 13 between them. A p-type diffusion region 121 that limits the movement of saturated charges is formed in the semiconductor substrate 11 between the inter-pixel isolation portion 13 and the second isolation portion 14B, and an n-type diffusion region 122 that serves as an overflow path OFP2 is formed on the first surface 11S1 directly below the transfer gate 31G2. The transfer gate 31G1 provided on the inter-pixel isolation portion 13 on an extension of the first isolation portion 14A also has a configuration similar to that of the transfer gate 31G2.

[0084] In this way, in the photodetector 1A of this modification, the transfer gate 31G1 is provided on the inter-pixel isolation portion 13 on an extension of the first isolation portion 14A, and the transfer gate 31G2 is provided on the inter-pixel isolation portion 13 on an extension of the second isolation portion 14B, and by applying a voltage to these transfer gates 31G1 and 31G2, the potentials of the overflow paths OFP1 and OFP2 can be controlled. Even with this configuration, the same effects as in the first embodiment can be obtained.

[0085] 10 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 1B) according to a second modification of the present disclosure. Like the photodetector 1 of the first embodiment, the photodetector 1B is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0086] In the first embodiment described above, an example was shown in which the longitudinal lengths of the first isolation portion 14A and the second isolation portion 14B were changed to provide a difference in potential between the overflow path OFP1 formed in the X-axis direction and the overflow path OFP2 formed in the Y-axis direction, but this is not limiting. In the photodetector 1B of this modified example, the widths in the lateral direction of the first isolation portion 14A and the second isolation portion 14B are changed to provide a difference in potential between the overflow path OFP1 formed in the X-axis direction and the overflow path OFP2 formed in the Y-axis direction.

[0087] Specifically, in the photodetector 1B, the width W1 in the short side direction of the first isolation portion 14A, which extends in the Y-axis direction and separates the photoelectric conversion portions 12-1 and 12-2 adjacent to each other in the X-axis direction and the photoelectric conversion portions 12-3 and 12-4 adjacent to each other in the X-axis direction, is wider than the width W2 in the short side direction of the second isolation portion 14B, which extends in the X-axis direction and separates the photoelectric conversion portions 12-1 and 12-4 adjacent to each other in the Y-axis direction and the photoelectric conversion portions 12-2 and 12-3 adjacent to each other in the Y-axis direction. As a result, the potential of the overflow path OFP1 formed between the inter-pixel isolation portion 13 and both ends of the first isolation portion 14A is higher than the potential of the overflow path OFP2 formed between the inter-pixel isolation portion 13 and both ends of the second isolation portion 14B.

[0088] The difference between the width W1 and the width W2 is preferably, for example, 50 nm to 100 nm, which allows a sufficient difference to be provided between the potential of the overflow path OFP1 and the potential of the overflow path OFP2.

[0089] In this way, in photodetector 1B of this modified example, by changing the widths in the short side direction of first isolation portion 14A and second isolation portion 14B, a difference is created between the potential of overflow path OFP1 formed between inter-pixel isolation portion 13 and both ends of first isolation portion 14A and the potential of overflow path OFP2 formed between inter-pixel isolation portion 13 and both ends of second isolation portion 14B. Even with this configuration, it is possible to obtain the same effects as in the first embodiment.

[0090] 11 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P constituting a photodetector (photodetector 2) according to a second embodiment of the present disclosure. FIG. 12A is a diagram illustrating an example of a cross-sectional configuration corresponding to line II-II′ shown in FIG. 11. FIG. 12B is a diagram illustrating an example of a cross-sectional configuration corresponding to line III-III′ shown in FIG. 11. Like the photodetector 1 of the first embodiment, the photodetector 2 is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0091] The photodetector 2 has a configuration in which a plurality of pixels (unit pixels P) capable of simultaneously acquiring imaging information and parallax information (phase difference information) are arranged in a matrix in a pixel array section 100A. Each unit pixel P is embedded in a semiconductor substrate 11 and includes a plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction and the Y-axis direction. The unit pixels P are surrounded by an inter-pixel isolation section 53 that separates adjacent unit pixels P in the pixel array section 100A. Each unit pixel P further includes an inter-element isolation section 54 including a first isolation section 54A provided between adjacent photoelectric conversion units 12 in the X-axis direction within the pixel and a second isolation section 54B provided between adjacent photoelectric conversion units 12 in the Y-axis direction within the pixel. The first isolation section 54A is composed of a pair of protrusions 54X that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation section 53 facing each other in the Y-axis direction. The second separation section 54B extends in the X-axis direction between a plurality of photoelectric conversion sections 12 adjacent to each other in the Y-axis direction and between a pair of protrusions 54X that constitute the first separation section 54A, and has gaps between both ends of the second separation section 54B and the inter-pixel separation section 53.

[0092] Here, the semiconductor substrate 11 corresponds to a specific example of a "semiconductor substrate" according to an embodiment of the present disclosure. The photoelectric conversion unit 12 corresponds to a specific example of a "photoelectric conversion unit" according to an embodiment of the present disclosure. The inter-pixel isolation unit 53 corresponds to a specific example of an "inter-pixel isolation unit" according to an embodiment of the present disclosure. The inter-element isolation unit 54 corresponds to a specific example of an "inter-element isolation unit" according to an embodiment of the present disclosure. The first isolation unit 54A corresponds to a specific example of a "first isolation unit" according to an embodiment of the present disclosure, and the pair of protrusions 54X correspond to a specific example of a "pair of protrusions" according to an embodiment of the present disclosure. The second isolation unit 54B corresponds to a specific example of a "second isolation unit" according to an embodiment of the present disclosure. The X-axis direction corresponds to a specific example of a "first direction" according to an embodiment of the present disclosure, and the Y-axis direction corresponds to a specific example of a "second direction" according to an embodiment of the present disclosure.

[0093] [Configuration of Unit Pixel] As described above, the photodetector 2 is, for example, a back-illuminated photodetector. Each unit pixel P arranged two-dimensionally in a matrix in the pixel array 100A has a configuration in which, for example, a light receiving section 10, a light collecting section 20 provided on a light incident side S1 of the light receiving section 10, and a multilayer wiring layer 30 provided on the side opposite to the light incident side S1 of the light receiving section 10 are stacked.

[0094] The light receiving unit 10 includes a semiconductor substrate 11 having a first surface 11S1 and a second surface 11S2 facing each other, and a plurality of photoelectric conversion units 12 embedded in the semiconductor substrate 11. The semiconductor substrate 11 is, for example, a silicon (Si) substrate, and has a p-well in a predetermined region. The photoelectric conversion units 12 are, for example, PIN (Positive Intrinsic Negative) photodiodes (PD), and have a p-n junction in a predetermined region of the semiconductor substrate 11. As described above, four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns are embedded in the unit pixel P.

[0095] The light receiving section 10 further has an inter-pixel isolation section 53 and an inter-element isolation section 54. P-type diffusion regions 121 are formed in the semiconductor substrate 11 on the side surfaces of the inter-pixel isolation section 13 and the inter-element isolation section 14. Furthermore, n-type diffusion regions 122 that constitute overflow paths OFP1 and OFP2 are formed in, for example, the first surface 11S1 of the semiconductor substrate 11 (see, for example, FIGS. 9A and 9B ).

[0096] The inter-pixel isolation portions 53 are intended to physically and electrically isolate adjacent unit pixels P, and are embedded in the semiconductor substrate 11 so as to surround each of the unit pixels P arranged in a two-dimensional array in the pixel array section 100A. In other words, the inter-pixel isolation portions 53 are embedded in the semiconductor substrate 11 so as to isolate adjacent unit pixels P, and are provided in, for example, a lattice pattern in the pixel array section 100A. In a cross-sectional view, the inter-pixel isolation portions 53 extend, for example, from the second surface 11S2 side of the semiconductor substrate 11 toward the first surface 11S1 side.

[0097] The inter-element isolation portion 54 physically and electrically isolates adjacent photoelectric conversion portions 12 within a pixel to prevent the outputs of adjacent phase difference detection elements (photoelectric conversion portions 12) from mixing together during phase difference detection. The inter-element isolation portion 54 includes, for example, a first isolation portion 54A provided between adjacent photoelectric conversion portions 12 in the X-axis direction within the pixel, and a second isolation portion 54B provided between adjacent photoelectric conversion portions 12 in the Y-axis direction. Specifically, as shown in FIG. 11, for example, the inter-element isolation section 54 has four photoelectric conversion sections 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns in the X-axis direction (row direction) and the Y-axis direction (column direction), and the inter-element isolation section 54 has a first isolation section 54A that extends in the Y-axis direction and isolates the photoelectric conversion section 12-1 and the photoelectric conversion section 12-2 that are adjacent in the X-axis direction and the photoelectric conversion section 12-3 and the photoelectric conversion section 12-4 that are adjacent in the Y-axis direction, and a second isolation section 54B that extends in the X-axis direction and isolates the photoelectric conversion section 12-1 and the photoelectric conversion section 12-4 that are adjacent in the Y-axis direction and the photoelectric conversion section 12-2 and the photoelectric conversion section 12-3 that are adjacent in the Y-axis direction. In the photodetector 2, by providing an inter-element isolation section 54 that isolates the four photoelectric conversion sections 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns from each other, phase difference information in all directions can be obtained in one unit pixel P.

[0098] In the photodetector 2 of this embodiment, as described above, the first isolation portion 54A is composed of a pair of protrusions 54X that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation portion 53 that face each other in the Y-axis direction. As described above, the second isolation portion 54B extends in the X-axis direction between the photoelectric conversion portions 12 that are adjacent in the Y-axis direction and between the pair of protrusions 54X that constitute the first isolation portion 54A, with gaps formed between both ends of the second isolation portion 54B and the inter-pixel isolation portion 53. Specifically, the first isolation portion 54A is composed of a pair of protrusions 54X that extend from the inter-pixel isolation portions 53 that face each other in the Y-axis direction to just before the center of the pixel and that separate the photoelectric conversion portions 12-1 and 12-2 and the photoelectric conversion portions 12-3 and 12-4 that are adjacent in the X-axis direction, respectively. The pair of protrusions 54X are each continuous with the inter-pixel isolation portion 53 and are separated from each other approximately at the center of the pixel. The second isolation portion 54B extends in the X-axis direction between the pair of protrusions 54X and separates the photoelectric conversion portions 12-1 and 12-4, and the photoelectric conversion portions 12-2 and 12-3, which are adjacent in the Y-axis direction. The second isolation portion 54B is provided independently from the inter-pixel isolation portion 53, extends in the X-axis direction between the pair of separated protrusions 54X, and has a gap between both ends of the second isolation portion 54B and the inter-pixel isolation portion 53.

[0099] In the photodetector 2, a pair of protrusions 54X are separated from each other approximately at the center of the pixel, and when extending between them in the X-axis direction, an overflow path OFP1 is formed between the pair and the second isolation portion 54B, and an overflow path OFP2 is formed between the inter-pixel isolation portion 53 and both ends of the second isolation portion 54B, and these are formed independently. This makes it possible to easily control the potential of the overflow path OFP1 and the overflow path OFP2 in the X-axis direction and the Y-axis direction, respectively.

[0100] A difference in potential between overflow path OFP1 and overflow path OFP2 can be set by adjusting the gap between the pair of protrusions 54X and the second isolation portion 54B extending therebetween in the X-axis direction, and the gap between both ends of the second isolation portion 54B and the inter-pixel isolation portion 53. For example, by designing the gap between the pair of protrusions 54X and the second isolation portion 54B extending therebetween in the X-axis direction to be narrower than the gap between both ends of the second isolation portion 54B and the inter-pixel isolation portion 53, the potential required to transfer saturated charge in overflow path OFP1 becomes higher than the potential required to transfer saturated charge in overflow path OFP2.

[0101] It is preferable that the difference between the gap between the pair of protrusions 54X and the second isolation portion 54B extending in the X-axis direction and the gap between both ends of the second isolation portion 54B and the inter-pixel isolation portion 53 be 50 nm or more and 200 nm or less. This allows a sufficient difference to be created between the potential of overflow path OFP1 and the potential of overflow path OFP2.

[0102] The inter-pixel isolation portion 53 and the inter-element isolation portion 54 are formed by trenches 15 that penetrate between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11 and have a so-called FTI (Full Trench Isolation) structure.

[0103] As in the first embodiment, the groove 15 may be filled with an optically transparent electrode film or a polysilicon film doped with an impurity such as boron (B), and a predetermined voltage may be applied thereto. This allows the potential of the overflow paths OFP1 and OFP2 to be controlled as desired. When an electrode film is filled therein, an insulating film made of a single layer or a multilayer film such as an SCF film or an SiO film is formed on the side and bottom of the groove 15 from the semiconductor substrate 11 side. When it is not necessary to apply a voltage to the inter-pixel isolation portion 53 and the inter-element isolation portion 54, the groove 15 may be filled with an insulating film such as an SCF film or an SiO film, as in the first embodiment.

[0104] The trenches 15 constituting the inter-pixel isolation portion 53 and the inter-element isolation portion 54 are not limited to the FTI structure as in the first embodiment, but may be of the STI structure. The trenches 15 having the STI structure may be formed from the first surface 11S1 side of the semiconductor substrate 11, or may be formed from the second surface 11S2 side of the semiconductor substrate 11.

[0105] The light-collecting unit 20 is provided on the light incident side S1 of the light-receiving unit 10, and includes, for example, a partition wall 23, a color filter layer 24, and a lens layer 25. Although not shown, a protective layer (for example, a protective layer 21) may be provided between the second surface 11S2 of the semiconductor substrate 11 and the partition wall 23 and color filter layer 24.

[0106] As in the first embodiment, the partition wall 23 may be formed of a single layer film made of one of SiO, TEOS, SiN, SiON, etc., or a laminated film made of two or more of these materials. Alternatively, the partition wall 23 may be formed of a material having light-shielding properties, as in the light-shielding film 22 in the first embodiment. Examples of light-shielding materials include W, Ag, Cu, Ti, Al, and alloys thereof. Other examples of materials for the partition wall 23 include metal compounds such as TiN.

[0107] The multilayer wiring layer 30 is provided on the opposite side of the light receiving section 10 from the light incident side S1. The multilayer wiring layer 30 has, for example, a configuration in which a plurality of wiring layers 31, 32, and 33 are stacked with an interlayer insulating layer 34 interposed therebetween. In the multilayer wiring layer 30, for example, in addition to the readout circuit 310 described above, a vertical drive circuit 181, a column signal processing circuit 182, a horizontal drive circuit 183, an output circuit 184, a control circuit 185, an input / output terminal 186, and the like are formed.

[0108] [Functions and Effects] In the photodetector 2 of this embodiment, unit pixels P each including a plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction and the Y-axis direction and formed embedded in the semiconductor substrate 11 are surrounded by an inter-pixel isolation portion 53 formed embedded in the semiconductor substrate 11. In the unit pixel P, an inter-element isolation portion 54 is formed embedded in the semiconductor substrate 11 to isolate the plurality of adjacent photoelectric conversion units 12 within the pixel, similar to the inter-pixel isolation portion 53. The inter-element isolation portion 54 includes a first isolation portion 54A provided between the plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction within the pixel, and a second isolation portion 54B provided between the plurality of photoelectric conversion units 12 adjacent to each other in the Y-axis direction.

[0109] The first isolation portion 54A is made up of a pair of protruding portions 54X that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation portion 53 that face each other in the Y-axis direction and are separated from each other approximately at the center of the pixel. The second isolation portion 54B extends in the X-axis direction between the plurality of photoelectric conversion portions 12 adjacent to each other in the Y-axis direction and between the pair of protruding portions 54X that constitute the first isolation portion 54A, and has gaps between both ends of the second isolation portion 54B and the inter-pixel isolation portion 54B. In the photodetector 2, when the pair of protruding portions 54X that are separated from each other approximately at the center of the pixel extend in the X-axis direction between the second isolation portion 54B and the pair of protruding portions 54X that are separated from each other approximately at the center of the pixel, an overflow path OFP1 is formed between the second isolation portion 54B and the pair of protruding portions 54X that are separated from each other approximately at the center of the pixel, and an overflow path OFP2 is formed between the inter-pixel isolation portion 53 and both ends of the second isolation portion 54B, respectively. As a result, compared to the photodetector device 1000A in which the overflow paths OFP1 and OFP2 are formed in a concentrated manner approximately at the center of the pixel described above, even if variations occur in the manufacturing process of the inter-element isolation portion 54, a difference can easily be created between the potential of the overflow path OFP1 and the potential of the overflow path OFP2.

[0110] As described above, in the photodetector 2 of this embodiment, it is possible to easily control the potentials of the overflow paths OFP1 and OFP2 formed in the X-axis direction and the Y-axis direction, thereby achieving both high imaging performance and phase difference detection performance.

[0111] Furthermore, in the photodetector 2 of this embodiment, an inter-element isolation portion 14 is provided approximately in the center of the pixel, thereby improving optical isolation performance compared to the photodetector 1000A described above.

[0112] 4. Third Embodiment Fig. 13 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P constituting a photodetector (photodetector 3) according to a third embodiment of the present disclosure. Fig. 14A is a diagram illustrating an example of a cross-sectional configuration corresponding to line IV-IV' shown in Fig. 13. Fig. 14B is a diagram illustrating an example of a cross-sectional configuration corresponding to line V-V' shown in Fig. 13. Like the photodetector 1 of the first embodiment, the photodetector 3 is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0113] The photodetector 3 has a configuration in which a plurality of pixels (unit pixels P) capable of simultaneously acquiring imaging information and parallax information (phase difference information) are arranged in a matrix in a pixel array section 100A. Each unit pixel P is embedded in a semiconductor substrate 11 and includes a plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction and the Y-axis direction. The unit pixels P are surrounded by an inter-pixel isolation section 63 that isolates adjacent unit pixels P in the pixel array section 100A. Each unit pixel P further includes an inter-element isolation section 64 including a first isolation section 64A provided between adjacent photoelectric conversion units 12 in the X-axis direction within the pixel and a second isolation section 64B provided between adjacent photoelectric conversion units 12 in the Y-axis direction. The first isolation section 14A and the second isolation section 14B each have a bottom within the semiconductor substrate 11, and the respective bottoms are formed at different depths.

[0114] Here, the semiconductor substrate 11 corresponds to a specific example of a "semiconductor substrate" according to an embodiment of the present disclosure. The photoelectric conversion unit 12 corresponds to a specific example of a "photoelectric conversion unit" according to an embodiment of the present disclosure. The inter-pixel isolation unit 63 corresponds to a specific example of an "inter-pixel isolation unit" according to an embodiment of the present disclosure. The inter-element isolation unit 64 corresponds to a specific example of an "inter-element isolation unit" according to an embodiment of the present disclosure. The first isolation unit 64A corresponds to a specific example of a "first isolation unit" according to an embodiment of the present disclosure. The second isolation unit 64B corresponds to a specific example of a "second isolation unit" according to an embodiment of the present disclosure. The X-axis direction corresponds to a specific example of a "first direction" according to an embodiment of the present disclosure, and the Y-axis direction corresponds to a specific example of a "second direction" according to an embodiment of the present disclosure.

[0115] [Configuration of Unit Pixel] As described above, the photodetector 3 is, for example, a back-illuminated photodetector. Each unit pixel P arranged two-dimensionally in a matrix in the pixel array 100A has a configuration in which, for example, a light receiving section 10, a light collecting section 20 provided on a light incident side S1 of the light receiving section 10, and a multilayer wiring layer 30 provided on the side opposite to the light incident side S1 of the light receiving section 10 are stacked.

[0116] The light receiving unit 10 includes a semiconductor substrate 11 having a first surface 11S1 and a second surface 11S2 facing each other, and a plurality of photoelectric conversion units 12 embedded in the semiconductor substrate 11. The semiconductor substrate 11 is, for example, a silicon (Si) substrate, and has a p-well in a predetermined region. The photoelectric conversion units 12 are, for example, PIN (Positive Intrinsic Negative) photodiodes (PD), and have a p-n junction in a predetermined region of the semiconductor substrate 11. As described above, four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns are embedded in the unit pixel P.

[0117] The light receiving section 10 further has an inter-pixel isolation section 63 and an inter-element isolation section 64. P-type diffusion regions 121 are formed in the semiconductor substrate 11 on the side surfaces of the inter-pixel isolation section 13 and the inter-element isolation section 14 (see, for example, FIGS. 9A and 9B ). Furthermore, n-type diffusion regions 122 that constitute overflow paths OFP1 and OFP2 are formed to a predetermined depth in the semiconductor substrate 11.

[0118] The inter-pixel isolation portions 63 are intended to physically and electrically isolate adjacent unit pixels P, and are embedded in the semiconductor substrate 11 so as to surround each of the unit pixels P arranged in a two-dimensional array in the pixel array section 100A. In other words, the inter-pixel isolation portions 63 are embedded in the semiconductor substrate 11 so as to isolate adjacent unit pixels P, and are provided in, for example, a lattice pattern in the pixel array section 100A. In a cross-sectional view, the inter-pixel isolation portions 63 extend, for example, from the second surface 11S2 side of the semiconductor substrate 11 toward the first surface 11S1 side.

[0119] The inter-pixel isolation portion 63 is configured by, for example, a trench 63H having an FTI structure that penetrates between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11. Alternatively, the inter-pixel isolation portion 63 may be, for example, a trench having an STI structure that has a bottom inside the semiconductor substrate 11.

[0120] As in the first embodiment, the groove 63H may be filled with an optically transparent electrode film or a polysilicon film doped with an impurity such as boron (B), and a predetermined voltage may be applied. When the electrode film is filled, an insulating film made of a single layer film or a multilayer film such as an SCF film or an SiO film is formed on the side and bottom of the groove 63H from the semiconductor substrate 11 side. Alternatively, the groove 63H may be filled with an insulating film such as an SCF film or an SiO film.

[0121] The inter-element isolation portion 64 serves to physically and electrically isolate adjacent photoelectric conversion portions 12 within a pixel to prevent the outputs of adjacent phase difference detection elements (photoelectric conversion portions 12) from mixing together during phase difference detection. The inter-element isolation portion 64 includes, for example, a first isolation portion 64A provided between adjacent photoelectric conversion portions 12 in the X-axis direction within the pixel, and a second isolation portion 64B provided between adjacent photoelectric conversion portions 12 in the Y-axis direction. Specifically, the inter-element isolation portion 64 has a first isolation portion 64A that extends in the Y-axis direction and isolates the photoelectric conversion portions 12-1 and 12-2 that are adjacent in the X-axis direction and the photoelectric conversion portions 12-3 and 12-4 that are adjacent in the X-axis direction, and a second isolation portion 64B that extends in the X-axis direction and isolates the photoelectric conversion portions 12-1 and 12-4 that are adjacent in the Y-axis direction and the photoelectric conversion portions 12-2 and 12-3 that are adjacent in the Y-axis direction. The first isolation portion 64A and the second isolation portion 64B have a generally cross shape that intersects with each other substantially at the center of the pixel in a plan view, and both ends of each isolation portion 64A and the second isolation portion 64B are in contact with the inter-pixel isolation portion 63. In the photodetector 1, by providing an inter-element isolation section 64 that isolates the four photoelectric conversion sections 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns from each other, phase difference information in all directions can be obtained in one unit pixel P.

[0122] In the photodetector 3 of this embodiment, the first isolation portion 64A and the second isolation portion 64B are each formed by a trench 64H having a so-called STI structure that extends from the second surface 11S2 toward the first surface 11S1 of the semiconductor substrate 11 and has a bottom inside the semiconductor substrate 11. The bottoms of the trenches 64H that form the first isolation portion 64A and the second isolation portion 64B are formed at different depths. Specifically, for example, the bottom of the first isolation portion 64A is located deeper than the bottom of the second isolation portion 64B and is formed closer to the first surface 11S1 of the semiconductor substrate 11.

[0123] In the photodetector 3, overflow paths OFP1 and OFP2 made of n-type diffusion regions 122 are formed below the bottoms of the first isolation portion 64A and the second isolation portion 64B, respectively. That is, in the photodetector 3, by adjusting the positions of the bottoms of the first isolation portion 64A and the second isolation portion 64B, overflow paths OFP1 and OFP2 can be formed separately in the depth direction of the semiconductor substrate 11. This makes it possible to easily control the potentials of overflow paths OFP1 and OFP2 in the X-axis direction and the Y-axis direction, respectively.

[0124] The light-collecting unit 20 is provided on the light incident side S1 of the light-receiving unit 10, and includes, for example, a partition wall 23, a color filter layer 24, and a lens layer 25. Although not shown, a protective layer (for example, a protective layer 21) may be provided between the second surface 11S2 of the semiconductor substrate 11 and the partition wall 23 and color filter layer 24.

[0125] As in the first embodiment, the partition wall 23 may be formed of a single layer film made of one of SiO, TEOS, SiN, SiON, etc., or a laminated film made of two or more of these materials. Alternatively, the partition wall 23 may be formed of a material having light-shielding properties, as in the light-shielding film 22 in the first embodiment. Examples of light-shielding materials include W, Ag, Cu, Ti, Al, and alloys thereof. Other examples of materials for the partition wall 23 include metal compounds such as TiN.

[0126] The multilayer wiring layer 30 is provided on the opposite side of the light receiving section 10 from the light incident side S1. The multilayer wiring layer 30 has, for example, a configuration in which a plurality of wiring layers 31, 32, and 33 are stacked with an interlayer insulating layer 34 interposed therebetween. In the multilayer wiring layer 30, for example, in addition to the readout circuit 310 described above, a vertical drive circuit 181, a column signal processing circuit 182, a horizontal drive circuit 183, an output circuit 184, a control circuit 185, an input / output terminal 186, and the like are formed.

[0127] [Method for Manufacturing Inter-element Isolation Portion] Figures 15A to 15D show an example of a method for manufacturing the inter-element isolation portion 64 shown in Figure 13. Note that (B) in Figures 15A to 15D schematically shows a cross-sectional configuration corresponding to line CC' shown in (A) in each figure.

[0128] First, as shown in FIG. 15A, a trench 63H penetrating the semiconductor substrate 11 from the second surface 11S2 side of the semiconductor substrate 11 is formed by photolithography and etching.

[0129] Next, as shown in FIG. 15B, a groove 64H is formed between adjacent photoelectric conversion units 12 from the second surface 11S2 side of the semiconductor substrate 11 by photolithography and etching.

[0130] Subsequently, as shown in FIG. 15C, for example, a mask 161 is patterned on the semiconductor substrate 11 except for the groove 64H extending in the Y-axis direction.

[0131] Next, as shown in FIG. 15D, the semiconductor substrate 11 exposed from the mask 161 is etched again to deepen the trench 64H, and then the mask 161 is removed.

[0132] Thereafter, for example, an SCF film is formed on the side and bottom surfaces of the trenches 63H and 64H and on the second surface 11S2 of the semiconductor substrate 11 using ALD, and then, for example, an SiO film is formed using ALD to fill the trenches 63H and 64H. Thereafter, the SCF film and SiO film formed on the second surface 11S2 of the semiconductor substrate 11 are removed by, for example, CMP. As a result of the above, the element isolation portion 64 shown in FIG. 13 is formed.

[0133] [Functions and Effects] In the photodetector 3 of this embodiment, unit pixels P each including a plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction and the Y-axis direction and formed embedded in the semiconductor substrate 11 are surrounded by an inter-pixel isolation portion 63 formed embedded in the semiconductor substrate 11. In the unit pixels P, inter-element isolation portions 64 that isolate the plurality of adjacent photoelectric conversion units 12 within the pixel are formed embedded in the semiconductor substrate 11, similar to the inter-pixel isolation portion 63. The inter-element isolation portion 64 includes a first isolation portion 64A provided between the plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction within the pixel, and a second isolation portion 64B provided between the plurality of photoelectric conversion units 12 adjacent to each other in the Y-axis direction.

[0134] The first isolation portion 64A and the second isolation portion 64B each have a bottom within the semiconductor substrate 11, and the respective bottoms are formed at different depths. An overflow path OFP1 is formed in the semiconductor substrate 11 below the bottom of the first isolation portion 64A, and an overflow path OFP2 is formed in the semiconductor substrate 11 below each bottom of the second isolation portion 64B. This makes it easier to create a difference between the potential of overflow path OFP1 and the potential of overflow path OFP2, compared to the photodetector device 1000A described above in which the overflow paths OFP1 and OFP2 are formed in a concentrated manner approximately at the center of the pixel.

[0135] As described above, in the photodetector 3 of this embodiment, it is possible to easily control the potentials of the overflow paths OFP1 and OFP2 formed in the X-axis direction and the Y-axis direction, thereby achieving both high imaging performance and phase difference detection performance.

[0136] Furthermore, in the photodetector 3 of this embodiment, an inter-element separation section 64 is provided approximately in the center of the pixel on the second surface 11S2 side of the semiconductor substrate 11, which is the light incident surface, so that the optical separation performance can be improved compared to the photodetector 1000A described above.

[0137] Furthermore, in the photodetector 3 of this embodiment, the first separation section 64A that separates multiple photoelectric conversion sections 12 adjacent to each other in the X-axis direction and the second separation section 64B that separates multiple photoelectric conversion sections 12 adjacent to each other in the Y-axis direction are formed together, thereby reducing misalignment of the first separation section 64A and the second separation section 64B in the X-axis and Y-axis directions.

[0138] 5. Modifications (5-1. Modification 3) FIG. 16 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 3A) according to Modification 3 of the present disclosure. FIG. 17A is a diagram illustrating an example of a cross-sectional configuration corresponding to line VI-VI' shown in FIG. 16. FIG. 17B is a diagram illustrating an example of a cross-sectional configuration corresponding to line VII-VII' shown in FIG. 16. Like the photodetector 1 of the first embodiment, the photodetector 3A is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0139] In the third embodiment, the first isolation portion 64A and the second isolation portion 64B are provided extending from the second surface 11S2 side of the semiconductor substrate 11, which serves as the light incident surface, toward the first surface 11S1, and have bottoms with different depths on the first surface 11S1 side. However, this is not limiting. The photodetector 3A of this modified example is provided with the first isolation portion 64A and the second isolation portion 64B extending from the first surface 11S1 side of the semiconductor substrate 11 toward the second surface 11S2, and have bottoms with different depths on the second surface 11S2 side. In the photodetector 3A, the overflow path OFP1 and the overflow path OFP2 are formed below the bottoms of the first isolation portion 64A and the second isolation portion 64B, which are provided on the second surface 11S2 side of the semiconductor substrate 11.

[0140] As described above, in the photodetector 3A of this modification, the first separation portion 64A and the second separation portion 64B are provided, which extend from the first surface 11S1 side of the semiconductor substrate 11 opposite the light incident side S1 toward the second surface 11S2 and have bottoms with different depths on the second surface 11S2 side. While this results in inferior optical separation performance compared to the photodetector 3 of the third embodiment, it is possible to easily control the potentials of the overflow paths OFP1 and OFP2 formed in the X-axis and Y-axis directions. This makes it possible to achieve both high imaging performance and phase difference detection performance.

[0141] Furthermore, in the photodetector 3A of this modified example, similar to the photodetector 3 of the third embodiment, misalignment of the first separation portion 64A and the second separation portion 64B in the X-axis direction and the Y-axis direction can be reduced.

[0142] (5-2. Modification 4) FIG. 18 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 3B) according to Modification 4 of the present disclosure. FIG. 19A is a diagram illustrating an example of a cross-sectional configuration corresponding to line VIII-VIII′ shown in FIG. 18. FIG. 19B is a diagram illustrating an example of a cross-sectional configuration corresponding to line IX-IX′ shown in FIG. 18. Like the photodetector 1 of the first embodiment, the photodetector 3B is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0143] In the third embodiment, the first isolation portion 64A and the second isolation portion 64B are provided extending from the second surface 11S2 side of the semiconductor substrate 11, which is the light incident surface, toward the first surface 11S1, and have bottoms with different depths on the first surface 11S1 side. However, this is not limiting. In the photodetector 3B of this modified example, one of the first isolation portion 64A and the second isolation portion 64B is provided from the first surface 11S1 side of the semiconductor substrate 11, and the other is provided from the second surface 11S2 side of the semiconductor substrate 11.

[0144] Specifically, in the photodetector 3B, for example, a first separation portion 64A is provided that extends from the first surface 11S1 side toward the second surface 11S2 of the semiconductor substrate 11 and has a bottom on the second surface 11S2 side, and a second separation portion 64B is provided that extends from the second surface 11S2 side toward the first surface 11S1 of the semiconductor substrate 11 and has a bottom on the first surface 11S1 side. In the photodetector 3B, an overflow path OFP1 is formed on the second surface 11S2 side of the semiconductor substrate 11, and an overflow path OFP2 is formed on the first surface 11S1 side of the semiconductor substrate 11.

[0145] As described above, in the photodetector 3B of this modification, one of the first separator 64A and the second separator 64B is provided from the first surface 11S1 side of the semiconductor substrate 11, and the other is provided from the second surface 11S2 side of the semiconductor substrate 11. As a result, although the optical separation performance is inferior compared to the photodetector 3 of the third embodiment, the overflow paths OFP1 and OFP2 can be more clearly formed in the depth direction of the semiconductor substrate 11, and therefore, compared to the third embodiment, the potentials of the overflow paths OFP1 and OFP2 formed in the X-axis direction and the Y-axis direction can be more easily controlled. Therefore, it is possible to achieve both high imaging performance and phase difference detection performance.

[0146] (5-3. Modification 5) FIG. 20 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 3C) according to Modification 5 of the present disclosure. FIG. 21A illustrates an example of a cross-sectional configuration corresponding to line X-X' illustrated in FIG. 20. FIG. 21B illustrates an example of a cross-sectional configuration corresponding to line XI-XI' illustrated in FIG. 20. FIG. 22A illustrates another example of a cross-sectional configuration corresponding to line X-X' illustrated in FIG. 20. FIG. 22B illustrates another example of a cross-sectional configuration corresponding to line XI-XI' illustrated in FIG. 20. Like the photodetector 1 of the first embodiment, the photodetector 3C is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0147] In the third embodiment, an example was shown in which the first separation portion 64A and the second separation portion 64B were provided so as to intersect with each other substantially at the center of the pixel, but this is not limited to this. In the photodetector 3C of this modified example, one of the first separation portion 64A and the second separation portion 64B is configured as a pair of protrusions 64X that are separated from each other substantially at the center of the pixel, similar to the first separation portion 54A in the second embodiment, and the other extends between the pair of protrusions 64X and is continuous with the inter-pixel separation portion 63.

[0148] Specifically, for example, in the photodetector 3C, the second separation portion 64B is formed as a pair of protrusions 64X that protrude toward the center of the pixel from a pair of sides of the inter-pixel separation portion 63 that face each other in the X-axis direction, and the first separation portion 64A extends between the pair of protrusions 64X that are separated from each other approximately at the center of the pixel and is continuous with a pair of sides of the inter-pixel separation portion 63 that face each other in the Y-axis direction. In the photodetector 3C, the first separation portion 64A extends from the second surface 11S2 side of the semiconductor substrate 11, which is the light incident surface, toward the first surface 11S1 and has a bottom on the first surface 11S1 side. The second separation portion 64B penetrates between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11 and has a gap between it and the first separation portion 64A approximately at the center of the pixel. In the photodetector 3C, the overflow path OFP1 is formed on the first surface 11S1 side of the semiconductor substrate 11, and the overflow path OFP2 is formed in the gap between the first isolation portion 64A and the second isolation portion 64B at approximately the center of the pixel. In other words, the overflow path OFP2 can be formed arbitrarily in the depth direction of the semiconductor substrate 11.

[0149] 22A and 22B , the first separation part 64A may extend from the first surface 11S1 side of the semiconductor substrate 11 opposite to the light incident side S1 toward the second surface 11S2, and have a bottom on the first surface 11S1 side, as in the above-described modification example 3. In this case, the overflow path OFP1 is provided on the second surface 11S2 side of the semiconductor substrate 11.

[0150] As described above, in the photodetector 3C of this modification, one of the first isolation portion 64A and the second isolation portion 64B is configured as a pair of protrusions 64X separated from each other approximately at the center of the pixel, similar to the first isolation portion 54A of the second embodiment, and the other extends between the pair of protrusions 64X and is continuous with the inter-pixel isolation portion 63. As a result, although the optical isolation performance is inferior to that of the photodetector 3 of the third embodiment, the overflow paths OFP1 and OFP2 can be more clearly formed in the depth direction of the semiconductor substrate 11, and therefore, compared to the third embodiment, the potentials of the overflow paths OFP1 and OFP2 formed in the X-axis direction and the Y-axis direction can be more easily controlled. This makes it possible to achieve both high imaging performance and phase difference detection performance.

[0151] (5-4. Modification 6) FIG. 23 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 3D) according to Modification 6 of the present disclosure. FIG. 24A illustrates an example of a cross-sectional configuration corresponding to line XII-XII′ shown in FIG. 23 . FIG. 24B illustrates an example of a cross-sectional configuration corresponding to line XIII-XIII′ shown in FIG. 23 . FIG. 25A illustrates another example of a cross-sectional configuration corresponding to line XII-XII′ shown in FIG. 23 . FIG. 25B illustrates another example of a cross-sectional configuration corresponding to line XIII-XIII′ shown in FIG. 23 . Like the photodetector 1 of the first embodiment, the photodetector 3D is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0152] In the third embodiment, an example was shown in which the formation positions of overflow path OFP1 and overflow path OFP2 were differentiated by changing the depths of grooves 64H that constitute first isolation portion 64A and second isolation portion 64B, but this is not limiting. In a photodetector 3D of this modified example, grooves 64H that extend in the X-axis direction and the Y-axis direction and have bottoms at the same depth in semiconductor substrate 11 are formed, and a p-type diffusion region 641 is further provided at the bottom of groove 64H that extends in the X-axis direction or the Y-axis direction, thereby providing first isolation portion 64A and second isolation portion 64B that are substantially different in depth.

[0153] Specifically, for example, in the photodetector 3D, trenches 64H extending in the X-axis direction and the Y-axis direction and having bottoms at the same depth in the semiconductor substrate 11 are formed, and a p-type diffusion region 641 is provided at the bottom of the trench 64H extending in the Y-axis direction. As a result, the first isolation portion 64A becomes an inter-element isolation portion 64 having a bottom at a position substantially deeper than the second isolation portion 64B. In the photodetector 3D, the overflow path OFP1 is formed near the first surface 11S1 of the semiconductor substrate 11 below the p-type diffusion region 641, and the overflow path OFP2 is formed below the trench 64H extending in the X-axis direction that constitutes the second isolation portion 64B, specifically, closer to the second surface 11S2 of the semiconductor substrate 11 than the overflow path OFP1.

[0154] In addition, the first separation portion 64A and the second separation portion 64B may be configured, for example, as shown in Figures 25A and 25B, to extend from the first surface 11S1 side of the semiconductor substrate 11 opposite the light incident side S1 toward the second surface 11S2, and have a bottom on the first surface 11S1 side.

[0155] As described above, in the photodetector 3D of this modified example, grooves 64H are formed in the semiconductor substrate 11, extending in the X-axis direction and the Y-axis direction, and have bottoms at the same depth. A p-type diffusion region 641 is provided at the bottom of the groove 64H extending in the X-axis direction or the Y-axis direction. Even with this configuration, as in the third embodiment, it is possible to easily control the potential of the overflow paths OFP1 and OFP2 formed in the X-axis direction and the Y-axis direction. Therefore, it is possible to achieve both high imaging performance and phase difference detection performance.

[0156] Furthermore, in the photodetector 3D of this modified example, similar to the photodetector 3 of the third embodiment, misalignment of the first separation portion 64A and the second separation portion 64B in the X-axis direction and the Y-axis direction can be reduced.

[0157] 6. Fourth Embodiment (A) of FIG. 26A is a schematic diagram illustrating an example of a planar configuration of a unit pixel P (e.g., a green pixel Pg) constituting a photodetector (photodetector 4) according to a fourth embodiment of the present disclosure. (B) of FIG. 26A is a schematic diagram illustrating an example of a planar configuration of a unit pixel P (e.g., a red pixel Pr and a blue pixel Pb) constituting a photodetector (photodetector 4) according to the fourth embodiment of the present disclosure. FIG. 26B is a schematic plan view illustrating an example of an arrangement of the red pixel Pr, the green pixel Pg, and the blue pixel Pb in the pixel array unit 100A. Like the photodetector 1 according to the first embodiment, the photodetector 4 is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0158] The photodetector 4 has a configuration in which a plurality of pixels (unit pixels P) capable of simultaneously acquiring imaging information and parallax information (phase difference information) are arranged in a matrix in the pixel array section 100A. Each unit pixel P is embedded in the semiconductor substrate 11 and includes a plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction and the Y-axis direction. The unit pixels P are surrounded by an inter-pixel isolation section 73 that isolates adjacent unit pixels P in the pixel array section 100A. Each unit pixel P further includes an inter-element isolation section 74 including a first isolation section 74A provided between adjacent photoelectric conversion units 12 in the X-axis direction within the pixel and a second isolation section 74B provided between adjacent photoelectric conversion units 12 in the Y-axis direction within the pixel. The first isolation section 74A is composed of a pair of protrusions 74X1 that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation section 73 facing each other in the Y-axis direction. The second separation portion 74B is composed of a pair of protrusions 74X2 that protrude toward the center of the pixel from a pair of sides of the inter-pixel separation portion 73 that face each other in the X-axis direction. The first separation portion 74A and the second separation portion 74B have different circumferential lengths, and when, for example, the X-axis direction is the phase difference acquisition direction and the Y-axis direction is a direction other than the phase difference acquisition direction, the circumferential length of the second separation portion 74B is shorter than the circumferential length of the first separation portion 74A.

[0159] Here, the semiconductor substrate 11 corresponds to a specific example of a "semiconductor substrate" according to an embodiment of the present disclosure. The photoelectric conversion unit 12 corresponds to a specific example of a "photoelectric conversion unit" according to an embodiment of the present disclosure. The inter-pixel isolation unit 73 corresponds to a specific example of an "inter-pixel isolation unit" according to an embodiment of the present disclosure. The inter-element isolation unit 74 corresponds to a specific example of an "inter-element isolation unit" according to an embodiment of the present disclosure. The first isolation unit 74A corresponds to a specific example of a "first isolation unit" according to an embodiment of the present disclosure, and the pair of protrusions 74X1 correspond to a specific example of a "pair of first protrusions" according to an embodiment of the present disclosure. The second isolation unit 74B corresponds to a specific example of a "second isolation unit" according to an embodiment of the present disclosure, and the pair of protrusions 74X2 correspond to a specific example of a "pair of second protrusions" according to an embodiment of the present disclosure. The X-axis direction corresponds to a specific example of a "first direction" according to an embodiment of the present disclosure, and the Y-axis direction corresponds to a specific example of a "second direction" according to an embodiment of the present disclosure.

[0160] [Configuration of Unit Pixel] As described above, the photodetector 4 is, for example, a back-illuminated photodetector. The unit pixels P arranged two-dimensionally in a matrix in the pixel array 100A have a configuration in which, for example, a light receiving section 10, a light collecting section 20 provided on a light incident side S1 of the light receiving section 10, and a multilayer wiring layer 30 provided on the side opposite to the light incident side S1 of the light receiving section 10 are stacked.

[0161] The light receiving unit 10 includes a semiconductor substrate 11 having a first surface 11S1 and a second surface 11S2 facing each other, and a plurality of photoelectric conversion units 12 embedded in the semiconductor substrate 11. The semiconductor substrate 11 is, for example, a silicon (Si) substrate, and has a p-well in a predetermined region. The photoelectric conversion units 12 are, for example, PIN (Positive Intrinsic Negative) photodiodes (PD), and have a p-n junction in a predetermined region of the semiconductor substrate 11. As described above, four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns are embedded in the unit pixel P.

[0162] The light receiving section 10 further has an inter-pixel isolation section 73 and an inter-element isolation section 74. P-type diffusion regions 121 are formed in the semiconductor substrate 11 on the side surfaces of the inter-pixel isolation section 73 and the inter-element isolation section 74 (see, for example, FIGS. 9A and 9B ). N-type diffusion regions 122 that form overflow paths OFP1 and OFP2 are patterned approximately at the center of the pixel on, for example, the first surface 11S1 of the semiconductor substrate 11.

[0163] The inter-pixel isolation portions 73 are intended to physically and electrically isolate adjacent unit pixels P, and are embedded in the semiconductor substrate 11 so as to surround each of the unit pixels P arranged in a two-dimensional array in the pixel array section 100A. In other words, the inter-pixel isolation portions 73 are embedded in the semiconductor substrate 11 so as to isolate adjacent unit pixels P, and are provided in, for example, a lattice pattern in the pixel array section 100A. In a cross-sectional view, the inter-pixel isolation portions 73 extend, for example, from the second surface 11S2 side of the semiconductor substrate 11 toward the first surface 11S1 side.

[0164] The inter-element isolation portion 74 physically and electrically isolates adjacent photoelectric conversion portions 12 within a pixel to prevent the outputs of adjacent phase difference detection elements (photoelectric conversion portions 12) from mixing during phase difference detection. The inter-element isolation portion 74 includes, for example, a first isolation portion 74A provided between adjacent photoelectric conversion portions 12 in the X-axis direction within the pixel and a second isolation portion 74B provided between adjacent photoelectric conversion portions 12 in the Y-axis direction. As described above, the first isolation portion 74A includes a pair of protrusions 74X1 that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation portion 73 that face each other in the Y-axis direction. As described above, the second isolation portion 74B includes a pair of protrusions 74X2 that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation portion 73 that face each other in the X-axis direction.

[0165] Specifically, the first isolation portion 74A extends from a pair of sides of the inter-pixel isolation portion 73 facing each other in the Y-axis direction to just before the center of the pixel, and is composed of a pair of protrusions 74X1 that separate the photoelectric conversion portions 12-1 and 12-2, and the photoelectric conversion portions 12-3 and 12-4, which are adjacent in the X-axis direction. The second isolation portion 74B extends from the inter-pixel isolation portion 73 facing each other in the X-axis direction to just before the center of the pixel, and is composed of a pair of protrusions 74X2 that separate the photoelectric conversion portions 12-1 and 12-4, and the photoelectric conversion portions 12-2 and 12-3, which are adjacent in the Y-axis direction. The pair of protrusions 74X1 and the pair of protrusions 74X2 are each separated from each other approximately at the center of the pixel. In the photodetector 4, by providing an inter-element isolation section 74 that isolates the four photoelectric conversion sections 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns from each other, phase difference information in all directions can be obtained in one unit pixel P.

[0166] 26B , the photodetector 4 has unit pixels (red pixel Pr, green pixel Pg, and blue pixel Pb) that detect red light (R), green light (G), and blue light (B) arranged in a Bayer pattern in the pixel array section 100A. In the photodetector 4 of this embodiment, the green pixel Pg acquires parallax information (phase difference information) from the photoelectric conversion units 12-1 and 12-2, and from the photoelectric conversion units 12-3 and 12-4 that are adjacent to each other in the X-axis direction, and acquires imaging information from the photoelectric conversion units 12-1 and 12-4, and from the photoelectric conversion units 12-2 and 12-3 that are adjacent to each other in the Y-axis direction. The red pixel Pr and the blue pixel Pb acquire parallax information (phase difference information) from the photoelectric conversion units 12-1 and 12-4, and the photoelectric conversion units 12-2 and 12-3, which are adjacent in the Y-axis direction, and acquire imaging information from the photoelectric conversion units 12-1 and 12-2, and the photoelectric conversion units 12-3 and 12-4, which are adjacent in the X-axis direction.

[0167] The first separation portion 74A and the second separation portion 74B have different circumferential lengths, and are configured such that, for example, when the X-axis direction is the phase difference acquisition direction and the Y-axis direction is a direction other than the phase difference acquisition direction, the circumferential length of the second separation portion 74B is shorter than the circumferential length of the first separation portion 74A.

[0168] Specifically, for example, as shown in Figure 26B, in the green pixel Pg, the longitudinal length of a pair of protrusions 74X2 provided between adjacent photoelectric conversion units 12-1 and 12-4 and between photoelectric conversion units 12-2 and 12-3 in the Y-axis direction for acquiring imaging information is configured to be shorter than the longitudinal length of a pair of protrusions 74X1 provided between adjacent photoelectric conversion units 12-1 and 12-2 and between photoelectric conversion units 12-3 and 12-4 in the X-axis direction for acquiring phase difference information. In the red pixel Pr and the blue pixel Pb, the longitudinal lengths of a pair of protrusions 74X1 provided between adjacent photoelectric conversion units 12-1 and 12-2 and between adjacent photoelectric conversion units 12-3 and 12-4 in the X-axis direction for acquiring imaging information are configured to be shorter than the longitudinal lengths of a pair of protrusions 74X2 provided between adjacent photoelectric conversion units 12-1 and 12-4 and between adjacent photoelectric conversion units 12-2 and 12-3 in the Y-axis direction for acquiring phase difference information. This allows a difference to be created between the potential of overflow path OFP1 and the potential of overflow path OFP2 for each color pixel (red pixel Pr, green pixel Pg, and blue pixel Pb).

[0169] The inter-pixel isolation portion 73 and the inter-element isolation portion 74 are formed by trenches 15 that penetrate between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11 and have a so-called FTI (Full Trench Isolation) structure.

[0170] The trench 15 is filled with an insulating film such as an SCF film or an SiO film.

[0171] The trenches 15 constituting the inter-pixel isolation portion 73 and the inter-element isolation portion 74 are not limited to the FTI structure as in the first embodiment, but may be of the STI structure. The trenches 15 having the STI structure may be formed from the first surface 11S1 side of the semiconductor substrate 11, or may be formed from the second surface 11S2 side of the semiconductor substrate 11.

[0172] The light-collecting unit 20 is provided on the light incident side S1 of the light-receiving unit 10, and includes, for example, a partition wall 23, a color filter layer 24, and a lens layer 25. Although not shown, a protective layer (for example, a protective layer 21) may be provided between the second surface 11S2 of the semiconductor substrate 11 and the partition wall 23 and color filter layer 24.

[0173] As in the first embodiment, the partition wall 23 may be formed of a single layer film made of one of SiO, TEOS, SiN, SiON, etc., or a laminated film made of two or more of these materials. Alternatively, the partition wall 23 may be formed of a material having light-shielding properties, as in the light-shielding film 22 in the first embodiment. Examples of light-shielding materials include W, Ag, Cu, Ti, Al, and alloys thereof. Other examples of materials for the partition wall 23 include metal compounds such as TiN.

[0174] The multilayer wiring layer 30 is provided on the opposite side of the light receiving section 10 from the light incident side S1. The multilayer wiring layer 30 has, for example, a configuration in which a plurality of wiring layers 31, 32, and 33 are stacked with an interlayer insulating layer 34 interposed therebetween. In the multilayer wiring layer 30, for example, in addition to the readout circuit 310 described above, a vertical drive circuit 181, a column signal processing circuit 182, a horizontal drive circuit 183, an output circuit 184, a control circuit 185, an input / output terminal 186, and the like are formed.

[0175] [Functions and Effects] In the photodetector 4 of this embodiment, unit pixels P each including a plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction and the Y-axis direction and formed embedded in the semiconductor substrate 11 are surrounded by an inter-pixel isolation portion 73 formed embedded in the semiconductor substrate 11. In the unit pixel P, an inter-element isolation portion 74 is formed embedded in the semiconductor substrate 11 to isolate the plurality of adjacent photoelectric conversion units 12 within the pixel, similar to the inter-pixel isolation portion 73. The inter-element isolation portion 74 includes a first isolation portion 74A provided between the plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction within the pixel, and a second isolation portion 74B provided between the plurality of photoelectric conversion units 12 adjacent to each other in the Y-axis direction.

[0176] The first separator 74A includes a pair of protrusions 74X1 that protrude from a pair of sides of the inter-pixel separator 73 that face each other in the Y-axis direction toward the center of the pixel and are separated from each other approximately at the center of the pixel. The second separator 74B includes a pair of protrusions 74X2 that protrude from a pair of sides of the inter-pixel separator 73 that face each other in the X-axis direction toward the center of the pixel and are separated from each other approximately at the center of the pixel. The light-detecting device 4 acquires phase difference information from photoelectric conversion units 12 that are adjacent in one of the X-axis and Y-axis directions, and acquires imaging information from photoelectric conversion units 12 that are adjacent in the other direction. The longitudinal length of the pair of protrusions (e.g., the pair of protrusions 74X2) provided between the photoelectric conversion units 12 that are adjacent in the direction in which the imaging information is acquired is shorter than the longitudinal length of the pair of protrusions (e.g., the pair of protrusions 74X1) provided between the photoelectric conversion units 12 that are adjacent in the direction in which the phase difference information is acquired. This allows a difference to be created in the potential of the overflow paths in each direction (overflow path OFP1 and overflow path OFP2).

[0177] 27 is a schematic diagram illustrating an example of a planar configuration of a unit pixel of a photodetector 1000B as a comparative example. As shown in FIG. 27, when pairs of protrusions 1014X1 and 1014X2 are provided with the same length between adjacent pixels PD1, PD2, PD3, and PD4 in the X-axis direction and Y-axis direction, the potentials of overflow paths OFP1 and OFP2 formed in the X-axis direction and Y-axis direction are controlled by, for example, adjusting the impurity concentration of an impurity diffusion region formed on the surface of a semiconductor substrate. 27 , in a photodetector 1000B, an n-type diffusion region 1022A is provided between a pair of protrusions 1014A provided between PD1, 2 and PD3, 4 adjacent to each other in the X-axis direction, and an n-type diffusion region 1022B in which n-type impurities are diffused to a higher concentration than n-type diffusion region 1022A is provided so as to surround a pair of protrusions 1014X2 provided between PD1, 4 and PD2, 3 adjacent to each other in the Y-axis direction. In this way, an overflow path OFP1 is formed between PD1, 2 and PD3, 4 adjacent to each other in the X-axis direction, and an overflow path OFP2 having a lower potential than overflow path OFP1 is formed between PD1, 4 and PD2, 3 adjacent to each other in the Y-axis direction.

[0178] In the manufacturing process of such a photodetector 1000B, it is important to align the pair of protrusions 1014X1, 1014X2 with the n-type diffusion regions 1022A, 1022B formed by, for example, ion implantation. When the photodetector 1000B acquires imaging information and phase difference information from different directions for each color pixel, as in the photodetector 4 of the present embodiment, if there is misalignment between the pair of protrusions 1014X1, 1014X2 and the n-type diffusion regions 1022A, 1022B formed by, for example, ion implantation, there is a concern that the characteristics of each color pixel will change, and this will become apparent in the captured image.

[0179] In contrast to this, in the present embodiment, as described above, the longitudinal lengths of the pair of protrusions 74X1 and 74X2 provided between adjacent photoelectric conversion units 12 in the X-axis direction and the Y-axis direction are changed depending on the direction in which imaging information and phase difference information are acquired, thereby creating a difference in potential between the overflow paths in each direction (overflow paths OFP1 and OFP2). This eliminates the need to form n-type diffusion regions with different impurity concentrations, as in the photodetector device 1000B.

[0180] As described above, in the photodetector device 4 of this embodiment, the potentials of the overflow paths OFP1 and OFP2 formed in the X-axis direction and the Y-axis direction can be easily controlled. This makes it possible to achieve both high imaging performance and phase difference detection performance. In addition, the manufacturing process can be simplified.

[0181] 7. Modifications (7-1. Modification 7) FIG. 28 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 4A) according to Modification 7 of the present disclosure. FIG. 29A is a diagram illustrating an example of a cross-sectional configuration corresponding to line XIV-XIV′ shown in FIG. 28. FIG. 29B is a diagram illustrating an example of a cross-sectional configuration corresponding to line XV-XV′ shown in FIG. 28. Like the photodetector 1 of the first embodiment, the photodetector 4A is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0182] In the fourth embodiment described above, the longitudinal lengths of the pair of protrusions 74X1, 74X2 that constitute the first isolation unit 74A and the second isolation unit 74B and are provided between adjacent photoelectric conversion units 12 in the X-axis direction and the Y-axis direction are changed depending on the direction in which imaging information and phase difference information are acquired, thereby creating a difference in the potential of the overflow path in each direction. However, this is not limited to this. In the photodetector 4A of this modified example, the lateral widths of the pair of protrusions 74X1, 74X2 that constitute the first isolation unit 74A and the second isolation unit 74B are changed depending on the direction in which imaging information and phase difference information are acquired, thereby creating a difference in the potential of the overflow path in each direction.

[0183] Specifically, in the light detection device 4A, the width W4 in the short direction of a pair of protrusions 74X2 provided between adjacent photoelectric conversion units 12-1 and 12-4 and between adjacent photoelectric conversion units 12-2 and 12-3 in a direction other than the direction in which imaging information is acquired (Y-axis direction) is narrower than the width W3 in the short direction of a pair of protrusions 74X1 provided between adjacent photoelectric conversion units 12-1 and 12-2 and between adjacent photoelectric conversion units 12-3 and 12-4 in the direction in which imaging information is acquired (X-axis direction). As a result, the potential of overflow path OFP2 between adjacent photoelectric conversion units 12-1 and 12-4 in the Y-axis direction and between photoelectric conversion units 12-2 and 12-3 is lower than the potential of overflow path OFP1 between adjacent photoelectric conversion units 12-1 and 12-2 in the X-axis direction and between photoelectric conversion units 12-3 and 12-4.

[0184] In this way, in the photodetector 4A of this modification, the widths in the short direction of the pair of protrusions 74X1, 74X2 constituting the first separation portion 74A and the second separation portion 74B are changed depending on the direction in which imaging information and phase difference information are acquired, so that a difference can be set in the potential of the overflow paths (overflow paths OFP1 and OFP2) in each direction. Even with this configuration, the same effects as those of the fourth embodiment can be obtained.

[0185] 30 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 4B) according to Modification 8 of the present disclosure. Like the photodetector 1 of the first embodiment, the photodetector 4B is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0186] In the fourth embodiment described above, an example was shown in which the second isolation portions 74B provided between the photoelectric conversion units 12-1 and 12-4 and between the photoelectric conversion units 12-2 and 12-3 that are adjacent in a direction other than the direction in which imaging information is acquired (the Y-axis direction) are provided as a pair of protrusions 74X2 that continue from a pair of sides of the inter-pixel isolation portion 73 that face each other in the X-axis direction, but this is not limited to this. In the photodetector 4B of this modified example, the pair of protrusions 74X2 that constitute the second isolation portion 74B are respectively separated between the photoelectric conversion units 12-1 and 12-4 and between the photoelectric conversion units 12-2 and 12-3.

[0187] In the photodetector 4B having such a configuration, a difference can be set in the potential of the overflow paths in each direction (overflow path OFP1 and overflow path OFP2). Therefore, the photodetector 4B of this modification can achieve the same effects as those of the fourth embodiment.

[0188] 31A to 31C are schematic diagrams illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 4C) according to a ninth modification of the present disclosure. Like the photodetector 1 of the first embodiment, the photodetector 4C is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0189] In the fourth embodiment, the present technology has been described using as an example a unit pixel P having a substantially square shape with a pair of sides facing each other in the X-axis direction and the Y-axis direction, in which a plurality of pixels are arranged in an array in the pixel array section 100A, but this is not limited to the planar shape of the unit pixel P. The unit pixel P of the photodetector 4C of this modified example has a substantially rhombic shape with a pair of vertices facing each other in the X-axis direction and the Y-axis direction, in which a plurality of pixels are arranged in an array in the pixel array section 100A.

[0190] In the unit pixel P having an approximately diamond shape, a pair of protrusions 74X1 constituting the first separation portion 74A and a pair of protrusions 74X2 constituting the second separation portion 74B each protrude toward the center of the pixel from a pair of vertices facing each other in the Y-axis direction and a pair of vertices facing each other in the X-axis direction, as shown in Figures 31A to 31C.

[0191] In the photodetector 4C shown in Figure 31A, as in the fourth embodiment described above, the longitudinal length of a pair of protrusions 74X2 provided between adjacent photoelectric conversion units 12-1 and 12-4 and between adjacent photoelectric conversion units 12-2 and 12-3 in a direction other than the direction in which imaging information is acquired (Y-axis direction) is shorter than the longitudinal length of a pair of protrusions 74X1 provided between adjacent photoelectric conversion units 12-1 and 12-2 and between adjacent photoelectric conversion units 12-3 and 12-4 in the direction in which imaging information is acquired (X-axis direction). 31B, similar to the above-described Modification 7, the width W4 in the short-side direction of a pair of protrusions 74X2 provided between adjacent photoelectric conversion units 12-1 and 12-4 and between adjacent photoelectric conversion units 12-2 and 12-3 in a direction other than the direction in which imaging information is acquired (the Y-axis direction) is narrower than the width W3 in the short-side direction of a pair of protrusions 74X1 provided between adjacent photoelectric conversion units 12-1 and 12-2 and between adjacent photoelectric conversion units 12-3 and 12-4 in the direction in which imaging information is acquired (the X-axis direction). In the photodetector 4C shown in FIG. 31C, similar to the above-described Modification 8, the pair of protrusions 74X2 constituting the second isolation unit 74B are respectively separated between the photoelectric conversion units 12-1 and 12-4 and between the photoelectric conversion units 12-2 and 12-3.

[0192] In the photodetector 4C having any of the above configurations, a difference can be provided in the potential of the overflow paths in each direction (overflow path OFP1 and overflow path OFP2). Therefore, the photodetector 4C of this modification can achieve the same effects as those of the fourth embodiment.

[0193] Furthermore, the photodetector 4C of this modification can reduce the number of well contacts 311 compared to a photodetector (e.g., the photodetector 4) including a plurality of substantially square unit pixels P. FIG. 32 schematically illustrates an example of the arrangement of well contacts 311 in a photodetector (e.g., the photodetector 4) including a plurality of substantially square unit pixels P arranged in an array. FIG. 33 schematically illustrates an example of the arrangement of well contacts 311 in a photodetector (e.g., the photodetector 4C) including a plurality of substantially diamond-shaped unit pixels P arranged in an array. In the photodetector 4, for example, including a plurality of substantially square unit pixels P arranged in an array, one well contact 311 is connected to four elements (photoelectric conversion units 12), whereas in the photodetector 4C, including a plurality of substantially diamond-shaped unit pixels P arranged in an array, one well contact 311 can be connected to eight elements (photoelectric conversion units 12).

[0194] (7-4. Modification 10) (A) of FIG. 34 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P (e.g., a green pixel Pg) constituting a photodetector (photodetector 4D) according to Modification 10 of the present disclosure. (B) of FIG. 34 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P (e.g., a red pixel Pr and a blue pixel Pb) constituting a photodetector (photodetector 4D) according to Modification 10 of the present disclosure. FIG. 35A is a diagram illustrating an example of a cross-sectional configuration corresponding to line XVI-XVI′ shown in FIG. 34. FIG. 35B is a diagram illustrating an example of a cross-sectional configuration corresponding to line XVII-XVI′ shown in FIG. 34. The photodetector 4D is, like the photodetector 1 of the first embodiment, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0195] In the fourth embodiment, an example was shown in which an insulating film was buried in the grooves 15 that constitute the first isolation portion 74A and the second isolation portion 74B, but this is not limited to this. In a photodetector 4D of this modified example, a portion of each of the second isolation portions 74B provided between the photoelectric conversion units 12-1 and 12-4 and between the photoelectric conversion units 12-2 and 12-3 that are adjacent in a direction (the Y-axis direction) other than the direction in which imaging information is acquired is formed by a p-type diffusion region 741.

[0196] In this way, in the photodetector 4D of this modified example, a portion of each of the second isolation portions 74B provided between the photoelectric conversion units 12-1 and 12-4 and between the photoelectric conversion units 12-2 and 12-3 that are adjacent in the Y-axis direction, which is not the direction in which imaging information is acquired, is formed by the p-type diffusion region 741. As a result, in addition to the effects of the fourth embodiment, compared to the case in which the second isolation portion 74B is formed of only an insulating film as in the first embodiment, it becomes possible to easily control the potential of the overflow path OFP2 so that saturated charges move more easily than in the overflow path OFP1.

[0197] 36A to 36C are schematic diagrams illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 4E) according to Modification 11 of the present disclosure. Like the photodetector 1 of the first embodiment, the photodetector 4E is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0198] The photodetector 4E of this modification further includes a plurality of protrusions 77 that are not intended to separate the photoelectric conversion units 12 within the pixel.

[0199] The protrusions 77 are provided to compensate for the loss of saturated charge (Qs) caused by shortening the longitudinal lengths of the pair of protrusions 74X2 in order to create a difference between the potentials of overflow paths OFP1 and OFP2 in the fourth embodiment, for example. The protrusions 77 are provided to protrude from the inter-pixel isolation portion 73 toward the center of the pixel at approximately 45° with respect to the X-axis direction and the Y-axis direction.

[0200] Specifically, as shown in Fig. 36A , for example, the protrusions 77 can be formed so as to protrude from the four corners of a plurality of substantially square unit pixels P toward the center of the pixels. As shown in Fig. 36B , for example, the protrusions 77 can be formed so as to protrude from the four sides of a plurality of substantially diamond-shaped unit pixels P toward the center of the pixels. However, the protrusions 77 may also be formed so as to protrude from the four sides of a plurality of substantially square unit pixels P toward the center of the pixels, as shown in Fig. 36C .

[0201] Like the inter-pixel isolation portion 73 and the inter-element isolation portion 74, the protruding portion 77 is configured by a trench 15 having a so-called FTI structure that penetrates between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11. Alternatively, the protruding portion 77 is not limited to the FTI structure and may have an STI structure. The trench 15 having the STI structure may be formed from the first surface 11S1 side of the semiconductor substrate 11, or may be formed from the second surface 11S2 side of the semiconductor substrate 11. Like the inter-pixel isolation portion 73 and the inter-element isolation portion 74, the trench 15 that configures the protruding portion 77 is filled with an insulating film such as an SCF film or a SiO film.

[0202] In this way, in the photodetection device 4E of this modified example, by providing multiple protrusions 77 within the pixel that are not intended to separate the photoelectric conversion section 12, it is possible to compensate for the loss of saturated charge (Qs) caused by shortening the perimeter of a pair of protrusions (for example, a pair of protrusions 74X2) to create a difference between the potential of overflow path OFP1 and the potential of overflow path OFP2.

[0203] 37 is a schematic diagram illustrating the planar configuration of a pixel array unit 100A of a photodetector (for example, photodetector 4) illustrating a 12th modification of the present disclosure. Figures 38A and 38B are schematic diagrams illustrating an example of the shapes of the first isolation portion 74A and the second isolation portion 74B at a position B in the left-right direction (X-axis direction) and a position C in the up-down direction (Y-axis direction) relative to a center A of the pixel array unit 100A shown in Figure 37.

[0204] For example, at position B located to the left and right of the center A of the pixel array unit 100A, unit pixels P are arranged in which the length of a pair of protrusions constituting the second isolation unit 74B is shorter than the length of a pair of protrusions constituting the first isolation unit 74A, so that the X-axis direction is the phase difference acquisition direction and the Y-axis direction is a direction that is not the phase difference acquisition direction. At position C located above and below the center A of the pixel array unit 100A, unit pixels P are arranged in which the length of a pair of protrusions constituting the first isolation unit 74A is shorter than the length of a pair of protrusions constituting the second isolation unit 74B, so that the Y-axis direction is the phase difference acquisition direction and the X-axis direction is a direction that is not the phase difference acquisition direction.

[0205] In this way, the first isolation portion 74A and the second isolation portion 74B provided in each unit pixel P constituting the pixel array portion 100A may have different circumferential lengths depending on the position (image height) within the pixel array portion 100A, thereby making it possible to correct deviations in sensitivity differences due to image height.

[0206] 8. Fifth Embodiment Fig. 39 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P constituting a photodetector (photodetector 5) according to a fifth embodiment of the present disclosure. Fig. 40A is a diagram illustrating an example of a cross-sectional configuration corresponding to line XVIII-XVIII' shown in Fig. 39. Fig. 40B is a diagram illustrating an example of a cross-sectional configuration corresponding to line XIX-XIX' shown in Fig. 39. Like the photodetector 1 of the first embodiment, the photodetector 5 is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0207] The photodetector 5 has a configuration in which a plurality of pixels (unit pixels P) capable of simultaneously acquiring imaging information and parallax information (phase difference information) are arranged in a matrix in a pixel array section 100A. Each unit pixel P is embedded in a semiconductor substrate 11 and includes a plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction and the Y-axis direction. The unit pixels P are surrounded by an inter-pixel isolation section 83 that separates adjacent unit pixels P in the pixel array section 100A. Each unit pixel P further includes an inter-element isolation section 84 including a first isolation section 84A provided between adjacent photoelectric conversion units 12 in the X-axis direction within the pixel and a second isolation section 84B provided between adjacent photoelectric conversion units 12 in the Y-axis direction. The first isolation section 84A is composed of a pair of protrusions 84X1 that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation section 83 facing each other in the Y-axis direction. The second isolation portion 84B is composed of a pair of protrusions 84X2 that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation portion 83 that face each other in the X-axis direction. Opposing side surfaces 84S1 of the pair of protrusions 84X1 within the semiconductor substrate 11 and opposing side surfaces 84S2 of the pair of protrusions 84X2 within the semiconductor substrate 11 are tapered surfaces, and the angles formed by these tapered surfaces and the second surface 11S2 are different from each other.

[0208] Here, the semiconductor substrate 11 corresponds to a specific example of a "semiconductor substrate" according to an embodiment of the present disclosure. The photoelectric conversion unit 12 corresponds to a specific example of a "photoelectric conversion unit" according to an embodiment of the present disclosure. The inter-pixel isolation unit 83 corresponds to a specific example of an "inter-pixel isolation unit" according to an embodiment of the present disclosure. The inter-element isolation unit 84 corresponds to a specific example of an "inter-element isolation unit" according to an embodiment of the present disclosure. The first isolation unit 84A corresponds to a specific example of a "first isolation unit" according to an embodiment of the present disclosure. The pair of protrusions 84X1 correspond to a specific example of a "pair of first protrusions" according to an embodiment of the present disclosure, and the side surface 84S1 corresponds to a specific example of a "first side surface" according to an embodiment of the present disclosure. The second isolation unit 84B corresponds to a specific example of a "second isolation unit" according to an embodiment of the present disclosure. The pair of protrusions 84X2 correspond to a specific example of a "pair of second protrusions" as an embodiment of the present disclosure, and the side surface 84S2 corresponds to a specific example of a "second side surface" as an embodiment of the present disclosure. The X-axis direction corresponds to a specific example of a "first direction" as an embodiment of the present disclosure, and the Y-axis direction corresponds to a specific example of a "second direction" as an embodiment of the present disclosure.

[0209] [Configuration of Unit Pixel] As described above, the photodetector 5 is, for example, a back-illuminated photodetector. The unit pixels P arranged two-dimensionally in a matrix in the pixel array 100A have a configuration in which, for example, a light receiving section 10, a light collecting section 20 provided on a light incident side S1 of the light receiving section 10, and a multilayer wiring layer 30 provided on the side opposite to the light incident side S1 of the light receiving section 10 are stacked.

[0210] The light receiving unit 10 includes a semiconductor substrate 11 having a first surface 11S1 and a second surface 11S2 facing each other, and a plurality of photoelectric conversion units 12 embedded in the semiconductor substrate 11. The semiconductor substrate 11 is, for example, a silicon (Si) substrate, and has a p-well in a predetermined region. The photoelectric conversion units 12 are, for example, PIN (Positive Intrinsic Negative) photodiodes (PD), and have a p-n junction in a predetermined region of the semiconductor substrate 11. As described above, four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns are embedded in the unit pixel P.

[0211] The light receiving section 10 further has an inter-pixel isolation section 83 and an inter-element isolation section 84. A p-type diffusion region 121 is formed in the semiconductor substrate 11 on the side surface of each of the inter-pixel isolation section 83 and the inter-element isolation section 84 (see, for example, FIGS. 9A and 9B ). A floating diffusion FD made of, for example, an n-type diffusion region 122 is formed in the center of the pixel on the first surface 11S1 of the semiconductor substrate 11.

[0212] The inter-pixel isolation portions 83 are intended to physically and electrically isolate adjacent unit pixels P, and are embedded in the semiconductor substrate 11 so as to surround each of the unit pixels P arranged in a two-dimensional array in the pixel array section 100A. In other words, the inter-pixel isolation portions 83 are embedded in the semiconductor substrate 11 so as to isolate adjacent unit pixels P, and are provided in, for example, a lattice pattern in the pixel array section 100A. In a cross-sectional view, the inter-pixel isolation portions 83 extend, for example, from the second surface 11S2 side of the semiconductor substrate 11 toward the first surface 11S1 side.

[0213] The inter-element isolation portion 84 physically and electrically isolates adjacent photoelectric conversion portions 12 within a pixel to prevent the outputs of adjacent phase difference detection elements (photoelectric conversion portions 12) from mixing during phase difference detection. The inter-element isolation portion 84 includes, for example, a first isolation portion 84A provided between adjacent photoelectric conversion portions 12 in the X-axis direction within the pixel and a second isolation portion 84B provided between adjacent photoelectric conversion portions 12 in the Y-axis direction. As described above, the first isolation portion 84A includes a pair of protrusions 84X1 that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation portion 83 that face each other in the Y-axis direction, and their opposing side surfaces 84S1 include tapered surfaces. Similarly, as described above, the second isolation portion 84B includes a pair of protrusions 84X2 that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation portion 83 that face each other in the X-axis direction, and their opposing side surfaces 84S2 include tapered surfaces.

[0214] Specifically, as shown in FIG. 39, for example, in four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 arranged in two rows and two columns in the X-axis direction (row direction) and the Y-axis direction (column direction), the inter-element isolation unit 84 has a first isolation unit 84A extending from the inter-pixel isolation unit 83 facing each other in the Y-axis direction to just before the center of the pixel and consisting of a pair of protrusions 84X1 that isolate the photoelectric conversion unit 12-1 and the photoelectric conversion unit 12-2 that are adjacent in the X-axis direction and the photoelectric conversion unit 12-3 and the photoelectric conversion unit 12-4 that are adjacent in the Y-axis direction, and a second isolation unit 84B extending from the inter-pixel isolation unit 83 facing each other in the X-axis direction to just before the center of the pixel and consisting of a pair of protrusions 84X2 that isolate the photoelectric conversion unit 12-1 and the photoelectric conversion unit 12-4 that are adjacent in the Y-axis direction and the photoelectric conversion unit 12-2 and the photoelectric conversion unit 12-3 that are adjacent in the Y-axis direction. The pair of protrusions 84X1 and the pair of protrusions 84X2 are separated from each other at approximately the center of the pixel. In the photodetector 5, by providing an inter-element separation portion 84 that separates the four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 arranged in 2 rows and 2 columns from each other, it is possible to acquire phase difference information in all directions in one unit pixel P.

[0215] As described above, the angle θ1 formed between the side surface 84S1 of each of the pair of protrusions 84X1 and the second surface 11S2 of the semiconductor substrate 11 and the angle θ2 formed between the side surface 84S2 of each of the pair of protrusions 84X2 and the second surface 11S2 of the semiconductor substrate 11 are different from each other. This allows the overflow path OFP1 formed in the X-axis direction and the overflow path OFP2 formed in the Y-axis direction to be formed at different depths in the depth direction (Z-axis direction) of the semiconductor substrate 11, and also makes it possible to provide a difference in potential between the overflow path OFP1 and the overflow path OFP2.

[0216] 40A and 40B , the side surface 84S1 of each of the pair of protrusions 84X1 and the side surface 84S2 of each of the pair of protrusions 84X2 are forward tapered surfaces that form obtuse angles with the second surface 11S2 of the semiconductor substrate 11. In other words, the distance between the opposing side surfaces 84S1 of each of the pair of protrusions 84X1 and the distance between the opposing side surfaces 84S2 of each of the pair of protrusions 84X2 increase from the first surface 11S1 toward the second surface 11S2 of the semiconductor substrate 11. As a result, the potential of overflow path OFP1 formed in the X-axis direction and the potential of overflow path OFP2 formed in the Y-axis direction increase from the first surface 11S1 toward the second surface 11S2 of the semiconductor substrate 11 (Si substrate), as shown in FIG. The transfer potential of the signal charges to the floating diffusions FD of the four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 in the pixel is the same as shown in FIG.

[0217] Furthermore, the angle θ1 formed between the side surface 84S1 of each of the pair of protrusions 84X1 and the second surface 11S2 of the semiconductor substrate 11 is larger than the angle θ2 formed between the side surface 84S2 of each of the pair of protrusions 84X2 and the second surface 11S2 of the semiconductor substrate 11. In other words, the distance between the pair of protrusions 84X1 on the second surface 11S2 of the semiconductor substrate 11 is wider than the distance between the pair of protrusions 84X2 on the second surface 11S2 of the semiconductor substrate 11. As a result, as shown in Figure 41, the potential on the second surface 11S2 side of overflow path OFP2 formed between adjacent photoelectric conversion units 12-1 and 12-4 and between photoelectric conversion units 12-2 and 12-3 in the Y-axis direction becomes higher than the potential on the second surface 11S2 side of overflow path OFP1 formed between adjacent photoelectric conversion units 12-1 and 12-2 and between photoelectric conversion units 12-3 and 12-4 in the X-axis direction.

[0218] In Figures 40A and 40B, an example is shown in which the side surface 84S1 of each of the pair of protrusions 84X1 and the side surface 84S2 of each of the pair of protrusions 84X2 are forward tapered surfaces in which the angles θ1 and θ2 with the second surface 11S2 of the semiconductor substrate 11 are obtuse angles, respectively, but this is not limited to this.

[0219] FIG. 43A shows another example of a cross-sectional configuration corresponding to line XVIII-XVIII' shown in FIG. 39. FIG. 43B shows another example of a cross-sectional configuration corresponding to line XIX-XIX' shown in FIG. 39. One of the side surfaces 84S1 of the pair of protrusions 84X1 and the side surfaces 84S2 of the pair of protrusions 84X2 (e.g., the side surfaces 84S1 of the pair of protrusions 84X1) may be an inversely tapered surface that forms an acute angle with the second surface 11S2 of the semiconductor substrate 11, and the other (e.g., the side surfaces 84S2 of the pair of protrusions 84X2) may be a forwardly tapered surface. This allows a difference in the potential of each of overflow paths OFP1 and OFP2 to be created in the depth direction (Z-axis direction) of the semiconductor substrate 11.

[0220] FIG. 44A shows another example of a cross-sectional configuration corresponding to line XVIII-XVIII' shown in FIG. 39. FIG. 44B shows another example of a cross-sectional configuration corresponding to line XIX-XIX' shown in FIG. 39. One of the side surfaces 84S1 of each of the pair of protrusions 84X1 and the side surfaces 84S2 of each of the pair of protrusions 84X2 (e.g., the side surfaces 84S1 of each of the pair of protrusions 84X1) may be an inversely tapered surface, and the other (e.g., the side surfaces 84S2 of each of the pair of protrusions 84X2) may be a surface perpendicular to the second surface 11S2 of the semiconductor substrate 11. This allows a difference in the potential of each of the overflow paths OFP1 and OFP2 to be created in the depth direction (Z-axis direction) of the semiconductor substrate 11. In this configuration, a difference in the potential of each of the overflow paths OFP1 and OFP2 can be created.

[0221] Table 1 summarizes combinations of the shapes of the side surfaces 84S1 of each of the pair of protrusions 84X1 and the side surfaces 84S2 of each of the pair of protrusions 84X2. By appropriately designing the taper angles of the side surfaces 84S1 of each of the pair of protrusions 84X1 and the side surfaces 84S2 of each of the pair of protrusions 84X2, and the spacing between the side surfaces 84S1 of each of the pair of protrusions 84X1 and the pair of protrusions 84X2, it is possible to create a difference between the potential of overflow path OFP1 and the potential of overflow path OFP2 in any of the cases shown in Table 1.

[0222]

[0223] The inter-pixel isolation portion 83 and the inter-element isolation portion 84 are formed by trenches 15 that penetrate between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11 and have a so-called FTI (Full Trench Isolation) structure.

[0224] The trench 15 is filled with an insulating film such as an SCF film or an SiO film.

[0225] The trenches 15 constituting the inter-pixel isolation portion 83 and the inter-element isolation portion 84 are not limited to an FTI structure, but may be an STI structure, as in the first embodiment. The trenches 15 having the STI structure may be formed from the first surface 11S1 side of the semiconductor substrate 11, or may be formed from the second surface 11S2 side of the semiconductor substrate 11.

[0226] The light-collecting unit 20 is provided on the light incident side S1 of the light-receiving unit 10, and includes, for example, a partition wall 23, a color filter layer 24, and a lens layer 25. Although not shown, a protective layer (for example, a protective layer 21) may be provided between the second surface 11S2 of the semiconductor substrate 11 and the partition wall 23 and color filter layer 24.

[0227] As in the first embodiment, the partition wall 23 may be formed of a single layer film made of one of SiO, TEOS, SiN, SiON, etc., or a laminated film made of two or more of these materials. Alternatively, the partition wall 23 may be formed of a material having light-shielding properties, as in the light-shielding film 22 in the first embodiment. Examples of light-shielding materials include W, Ag, Cu, Ti, Al, and alloys thereof. Other examples of materials for the partition wall 23 include metal compounds such as TiN.

[0228] The multilayer wiring layer 30 is provided on the opposite side of the light receiving section 10 from the light incident side S1. The multilayer wiring layer 30 has, for example, a configuration in which a plurality of wiring layers 31, 32, and 33 are stacked with an interlayer insulating layer 34 interposed therebetween. In the multilayer wiring layer 30, for example, in addition to the readout circuit 310 described above, a vertical drive circuit 181, a column signal processing circuit 182, a horizontal drive circuit 183, an output circuit 184, a control circuit 185, an input / output terminal 186, and the like are formed.

[0229] [Actions and Effects] In the photodetector 5 of this embodiment, a unit pixel P including a plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction and the Y-axis direction and formed embedded in the semiconductor substrate 11 is surrounded by an inter-pixel isolation portion 83 formed embedded in the semiconductor substrate 11. In the unit pixel P, an inter-element isolation portion 84 is formed embedded in the semiconductor substrate 11 to isolate the plurality of adjacent photoelectric conversion units 12 within the pixel, similar to the inter-pixel isolation portion 83. The inter-element isolation portion 84 includes a first isolation portion 84A provided between the plurality of photoelectric conversion units 12 adjacent to each other in the X-axis direction within the pixel, and a second isolation portion 84B provided between the plurality of photoelectric conversion units 12 adjacent to each other in the Y-axis direction.

[0230] The first isolation portion 84A consists of a pair of protrusions 84X1 that protrude from a pair of sides of the inter-pixel isolation portion 83 that face each other in the Y-axis direction toward the center of the pixel and are separated from each other approximately at the center of the pixel. The second isolation portion 84B consists of a pair of protrusions 84X2 that protrude from a pair of sides of the inter-pixel isolation portion 83 that face each other in the X-axis direction toward the center of the pixel and are separated from each other approximately at the center of the pixel. Opposing side surfaces 84S1 of the pair of protrusions 84X1 within the semiconductor substrate 11 and opposing side surfaces 84S2 of the pair of protrusions 84X2 within the semiconductor substrate 11 are tapered. The angle θ1 formed between the side surface 84S1 of each pair of protrusions 84X1 and the second surface 11S2 of the semiconductor substrate 11 and the angle θ2 formed between the side surface 84S2 of each pair of protrusions 84X2 and the second surface 11S2 of the semiconductor substrate 11 are different from each other. This makes it possible to easily provide a difference between the potential of the overflow path OFP1 and the potential of the overflow path OFP2.

[0231] As described above, in the photodetector device 5 of this embodiment, it is possible to easily control the potentials of the overflow paths OFP1 and OFP2 formed in the X-axis direction and the Y-axis direction, thereby achieving both high imaging performance and phase difference detection performance.

[0232] 45 schematically illustrates an example of a planar configuration of a unit pixel P of a photodetector (photodetector 5A) according to Modification 13 of the present disclosure. Like the photodetector 1 of the first embodiment, the photodetector 5A is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0233] In the fifth embodiment, an example was shown in which one floating diffusion FD made of an n-type diffusion region 122 is provided in the center of the pixel, and this one floating diffusion FD is shared by four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 provided in the pixel, but this is not limited to this. In the photodetector 5A of this modified example, for example, polysilicon 131 doped with n-type impurities is embedded as a floating diffusion FD contact in the center of each pair of sides of the inter-pixel isolation unit 83 facing each other in the X-axis direction, so as to straddle the inter-pixel isolation unit 83, and this one floating diffusion FD is shared by two photoelectric conversion units adjacent in the Y-axis direction within the pixel and by two photoelectric conversion units adjacent in the Y-axis direction of pixels adjacent to each other across the inter-pixel isolation unit 83.

[0234] The photodetector 5A having such a configuration can also obtain the same effects as those of the fifth embodiment.

[0235] 46 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 5B) according to a 14th modification of the present disclosure. Like the photodetector 1 of the first embodiment, the photodetector 5B is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0236] In the above-described modification 13, an example was shown in which polysilicon 131 provided across inter-pixel isolation portion 83 was shared by two photoelectric conversion portions adjacent in the Y-axis direction within a pixel and by two photoelectric conversion portions adjacent in the Y-axis direction of adjacent pixels with inter-pixel isolation portion 83 in between, but the following configuration is also possible: In photodetector 5B of this modification, polysilicon 131 provided across inter-pixel isolation portion 83 is separated between adjacent pixels by inter-pixel isolation portion 83.

[0237] The photodetector 5B having such a configuration can also obtain the same effects as those of the fifth embodiment.

[0238] 47 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 5C) according to a fifteenth modification of the present disclosure. Like the photodetector 1 of the first embodiment, the photodetector 5C is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0239] In the fifth embodiment, an example was shown in which one floating diffusion FD made of an n-type diffusion region 122 is provided in the center of a pixel, and this one floating diffusion FD is shared by four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 provided in the pixel, but this is not limited to this. In the photodetector 5C of this modified example, for example, one floating diffusion FD made of an n-type diffusion region 122 is provided in each of the four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 provided in the pixel, along the inter-pixel isolation unit 83 and the inter-element isolation unit 84.

[0240] The photodetector 5C having such a configuration can also achieve the same effects as those of the fifth embodiment.

[0241] 48 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 5D) according to a 16th modification of the present disclosure. Like the photodetector 1 of the first embodiment, the photodetector 5D is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0242] In the fifth embodiment, an example was shown in which one floating diffusion FD is provided in the center of the pixel, and this one floating diffusion FD is shared by four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 provided in the pixel, but this is not limited to this. In the photodetector 5D of this modified example, for example, at the four corners of a unit pixel P having a substantially square shape, polysilicon 131 doped with n-type impurities is embedded as a contact for the floating diffusion FD so as to straddle the inter-pixel isolation portion 83, and one floating diffusion FD is shared by four photoelectric conversion units adjacent to each other in the X-axis direction and the Y-axis direction, with the inter-pixel isolation portion 83 between them.

[0243] The photodetector 5D having such a configuration can also obtain the same effects as those of the fifth embodiment.

[0244] 49 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 5E) according to Modification 17 of the present disclosure. Like the photodetector 1 of the first embodiment, the photodetector 5E is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0245] In the above-described modification 13, for example, polysilicon 131 is embedded so as to straddle the inter-pixel isolation portion 83 at the four corners of a unit pixel P having a substantially square shape, and one floating diffusion FD is shared by four adjacent photoelectric conversion portions of four unit pixels P adjacent to each other in the X-axis direction and the Y-axis direction, with the inter-pixel isolation portion 83 sandwiched between them. However, the following configuration is also possible. In the photodetector 5E of this modification, the polysilicon 131 provided straddling the inter-pixel isolation portion 83 is separated between adjacent pixels by the inter-pixel isolation portion 83.

[0246] The photodetector 5E having such a configuration can also obtain the same effects as those of the fifth embodiment.

[0247] 50 is a schematic diagram illustrating an example of a planar configuration of a unit pixel P of a photodetector (photodetector 5F) according to Modification 18 of the present disclosure. Like the photodetector 1 of the first embodiment, the photodetector 5F is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0248] In the fifth embodiment, an example was shown in which one floating diffusion FD made of an n-type diffusion region 122 is provided in the center of the pixel, and this one floating diffusion FD is shared by four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 provided in the pixel, but this is not limited to this. In the photodetector 5F of this modified example, for example, at the four corners of a unit pixel P having a substantially square shape, one floating diffusion FD made of an n-type diffusion region 122 is provided in each of the four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 provided in the pixel, along the inter-pixel isolation unit 83 and the inter-element isolation unit 84.

[0249] The photodetector 5F having such a configuration also has the same structure as the fifth embodiment.

[0250] (9-7. Modification 19) FIG. 51 schematically illustrates an example of a planar configuration of a unit pixel P of a photodetector (photodetector 5G) according to Modification 19 of the present disclosure. FIG. 52A illustrates an example of a cross-sectional configuration corresponding to line XX-XX' illustrated in FIG. 51. FIG. 52B illustrates an example of a cross-sectional configuration corresponding to line XXI-XX' illustrated in FIG. 51. Like the photodetector 1 of the first embodiment, the photodetector 5G is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0251] In the fifth embodiment, the present technology has been described using an example of a unit pixel P including four photoelectric conversion units 12-1, 12-2, 12-3, and 12-4 adjacent to each other in the X-axis direction and the Y-axis direction, but the present technology can also be applied to unit pixels having other configurations. A photodetector 5G of this modified example has a plurality of unit pixels P, each including two photoelectric conversion units 12-1 and 12-2 adjacent to each other in the X-axis direction, arranged in a two-dimensional array.

[0252] The photodetector 5F has an inter-element isolation portion 84 that separates two photoelectric conversion portions 12-1 and 12-2 that are adjacent in the X-axis direction within a pixel. The inter-element isolation portion 84 is configured by a pair of protrusions 84X that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation portion 83 that face each other in the Y-axis direction. Opposing side surfaces 84S3 of the pair of protrusions 84X within the semiconductor substrate 11 are tapered surfaces, and the distance between the opposing side surfaces 84S3 of the pair of protrusions 84X increases, for example, from the first surface 11S1 side of the semiconductor substrate 11 toward the second surface 11S2.

[0253] In the photodetector 5F, a p-type diffusion region 121 is formed in the semiconductor substrate between the opposing side surfaces 84S3, and a region is provided locally where the p-type diffusion region 121 is not formed. As a result, an overflow path OFP is formed in the region where the p-type diffusion region 121 is not formed.

[0254] In this way, by applying this technology to a photodetector device 5F in which multiple unit pixels P, each including two photoelectric conversion units 12-1 and 12-2 adjacent to each other in the X-axis direction, are arranged in a two-dimensional array, it is possible to form an overflow path OFP without separately forming an n-type diffusion region.

[0255] 10. Sixth Embodiment Fig. 59 is a schematic plan view illustrating an example of the shape of the first isolation portions 94A of the red pixels Pr, green pixels Pg, and blue pixels Pb at the center A of the pixel array unit 100A illustrated in Fig. 59 . Fig. 60A is a schematic plan view illustrating an example of the shape of the first isolation portions 94A of the red pixels Pr, green pixels Pg, and blue pixels Pb at a position B1 to the right of the center A of the pixel array unit 100A illustrated in Fig. 59 . Fig. 60C is a schematic plan view illustrating an example of the shape of the first isolation portions 94A of the red pixels Pr, green pixels Pg, and blue pixels Pb at a position C1 below the center A of the pixel array unit 100A illustrated in Fig. 59 . Fig. 60D is a schematic plan view showing an example of the shape of the first isolation portion 94A of the red pixel Pr, the green pixel Pg, and the blue pixel Pb at a position D1 diagonally downward to the right with respect to the center A of the pixel array unit 100A shown in Fig. 59. The photodetector 6 is, like the photodetector 1 of the first embodiment, a CMOS image sensor or the like used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0256] The photodetector 6 has a configuration in which a plurality of pixels (unit pixels P) capable of simultaneously acquiring imaging information and parallax information (phase difference information) are arranged in a matrix in the pixel array section 100A. As shown in FIG. 60A , the photodetector 6 includes a plurality of unit pixels P (red pixels Pr, green pixels Pg, and blue pixels Pb) that detect red light (R), green light (G), or blue light (B). The red pixels Pr, green pixels Pg, and blue pixels Pb are arranged in a Bayer pattern in the pixel array section 100A. Each of the unit pixels P is embedded in the semiconductor substrate 11 and includes two photoelectric conversion units 12-1 and 12-2 adjacent to each other in the X-axis direction. Each of the unit pixels P is surrounded by an inter-pixel isolation unit 93 that isolates adjacent unit pixels P in the pixel array section 100A. Each of the unit pixels P further includes an inter-element isolation portion 94 including a first isolation portion 94A provided between adjacent photoelectric conversion portions 12 in the X-axis direction within the pixel. The first isolation portion 94A is composed of a pair of protrusions 94A1 and 94A2 that protrude from a pair of sides of the inter-pixel isolation portion 93 facing each other in the Y-axis direction toward the center of the pixel, with a gap G1 between the protrusions 94A1 and 94A2. In the photodetector 6 of this embodiment, the positions in the X-axis direction within the pixel of the pair of protrusions 94A1 and 94A2 that constitute the first isolation portion 94A and the position of the gap G1 within the pixel are configured to differ from each other depending on the position within the pixel array portion 100A and the wavelength to be detected.

[0257] Here, the semiconductor substrate 11 corresponds to a specific example of a "semiconductor substrate" according to an embodiment of the present disclosure. The photoelectric conversion unit 12 corresponds to a specific example of a "photoelectric conversion unit" according to an embodiment of the present disclosure. The inter-pixel isolation unit 93 corresponds to a specific example of an "inter-pixel isolation unit" according to an embodiment of the present disclosure. The inter-element isolation unit 94 corresponds to a specific example of an "inter-element isolation unit" according to an embodiment of the present disclosure. The first isolation unit 94A corresponds to a specific example of a "first isolation unit" according to an embodiment of the present disclosure, and the pair of protrusions 94A1, 94A2 correspond to a specific example of a "pair of first protrusions" according to an embodiment of the present disclosure. The X-axis direction corresponds to a specific example of a "first direction" according to an embodiment of the present disclosure, and the Y-axis direction corresponds to a specific example of a "second direction" according to an embodiment of the present disclosure.

[0258] [Configuration of Unit Pixel] Figure 61 is a schematic diagram illustrating an example of the cross-sectional configuration of a unit pixel (e.g., a green pixel Pg) taken along line XXI-XXI' in Figure 60B. As described above, the photodetector 6 is, for example, a back-illuminated photodetector. The unit pixels P arranged two-dimensionally in a matrix in the pixel array section 100A have a configuration in which, for example, a light receiving section 10, a light collecting section 20 provided on the light incident side S1 of the light receiving section 10, and a multilayer wiring layer 30 provided on the side opposite the light incident side S1 of the light receiving section 10 are stacked.

[0259] The light receiving section 10 includes a semiconductor substrate 11 having a first surface 11S1 and a second surface 11S2 facing each other, and a plurality of photoelectric conversion sections 12 embedded in the semiconductor substrate 11. The semiconductor substrate 11 is, for example, a silicon (Si) substrate, and has a p-well in a predetermined region. The photoelectric conversion sections 12 are, for example, PIN (Positive Intrinsic Negative) photodiodes (PD), and have a pn junction in a predetermined region of the semiconductor substrate 11. As described above, two photoelectric conversion sections 12-1 and 12-2 arranged in one row and two columns are embedded in each unit pixel P.

[0260] The light receiving section 10 further includes an inter-pixel isolation section 93 and an inter-element isolation section 94 .

[0261] The inter-pixel isolation portions 93 are intended to physically and electrically isolate adjacent unit pixels P, and are embedded in the semiconductor substrate 11 so as to surround each of the unit pixels P arranged in a two-dimensional array in the pixel array section 100A. In other words, the inter-pixel isolation portions 93 are embedded in the semiconductor substrate 11 so as to isolate adjacent unit pixels P, and are provided in, for example, a lattice pattern in the pixel array section 100A. In a cross-sectional view, the inter-pixel isolation portions 93 extend, for example, from the second surface 11S2 side of the semiconductor substrate 11 toward the first surface 11S1 side.

[0262] The inter-element isolation portion 94 is intended to physically and electrically isolate adjacent photoelectric conversion portions 12 within a pixel to prevent the outputs of adjacent phase difference detection elements (photoelectric conversion portions 12) from mixing together during phase difference detection. The inter-element isolation portion 94 has, for example, a first isolation portion 94A provided between adjacent photoelectric conversion portions 12 in the X-axis direction within the pixel. As described above, the first isolation portion 94A is made up of a pair of protrusions 94A1 and 94A2 that protrude toward the center of the pixel from a pair of sides of the inter-pixel isolation portion 93 that face each other in the Y-axis direction.

[0263] Specifically, the first isolation portion 94A extends from a pair of sides of the inter-pixel isolation portion 93 facing each other in the Y-axis direction to just before the center of the pixel, and is composed of a pair of protrusions 94A1 and 94A2 that separate the photoelectric conversion portion 12-1 and the photoelectric conversion portion 12-2 that are adjacent in the X-axis direction, with a gap G1 between the protrusions 94A1 and 94A2 as described above. In other words, the pair of protrusions 94A1 and 94A2 are separated from each other. The photodetector 6 can acquire phase difference information in the left-right direction for one unit pixel P by providing an inter-element isolation portion 94 that separates the two photoelectric conversion portions 12-1 and 12-2 arranged in one row and two columns from each other.

[0264] The inter-pixel isolation portion 93 and the inter-element isolation portion 94 are formed by trenches 15 that penetrate between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11 and have a so-called FTI (Full Trench Isolation) structure.

[0265] The trench 15 is filled with, for example, a polysilicon film 154. Alternatively, the trench 15 may be filled with an insulating film such as an SCF film or an SiO film.

[0266] The trenches 15 that form the inter-pixel isolation portion 93 and the inter-element isolation portion 94 are not limited to an FTI structure that penetrates between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11, and may be a DTI (Deep Trench Isolation) structure as shown in Fig. 62. The trenches 15 having the DTI structure may be formed from the first surface 11S1 side of the semiconductor substrate 11, or may be formed from the second surface 11S2 side of the semiconductor substrate 11.

[0267] The light-collecting unit 20 is provided on the light incident side S1 of the light-receiving unit 10, and includes, for example, a partition wall 23, a color filter layer 24, and a lens layer 25. Between the second surface 11S2 of the semiconductor substrate 11 and the partition wall 23 and the color filter layer 24, for example, a protective layer 21 is provided.

[0268] As in the first embodiment, the partition wall 23 may be formed of a single layer film made of one of SiO, TEOS, SiN, SiON, etc., or a laminated film made of two or more of these materials. Alternatively, the partition wall 23 may be formed of a material having light-shielding properties, as in the light-shielding film 22 in the first embodiment. Examples of light-shielding materials include W, Ag, Cu, Ti, Al, and alloys thereof. Other examples of materials for the partition wall 23 include metal compounds such as TiN.

[0269] The multilayer wiring layer 30 is provided on the opposite side of the light receiving section 10 from the light incident side S1. The multilayer wiring layer 30 has, for example, a configuration in which a plurality of wiring layers 31, 32, and 33 are stacked with an interlayer insulating layer 34 interposed therebetween. In the multilayer wiring layer 30, for example, in addition to the readout circuit 310 described above, a vertical drive circuit 181, a column signal processing circuit 182, a horizontal drive circuit 183, an output circuit 184, a control circuit 185, an input / output terminal 186, and the like are formed.

[0270] In the photodetector 6 of this embodiment, pupil correction is performed on each of a plurality of unit pixels P arranged two-dimensionally in a matrix in the pixel array section 100A, depending on its position within the pixel array section 100A. In the photodetector 6, as shown in FIG. 61 , for example, the light-focusing point is corrected by shifting the color filter layer 24 and a plurality of on-chip lenses 25L on the surface of the lens layer 25 in the incident direction of the incident light L. Furthermore, in the photodetector 6, the formation position of the first separation portion 94A in the X-axis direction and the position of the gap G1 between the pair of protrusions 94A1 and 94A2 that constitute the first separation portion 94A are adjusted for each of the red pixel Pr, green pixel Pg, and blue pixel Pb according to the position of the light-focusing point.

[0271] Specifically, for example, in the central portion A of the pixel array unit 100A, incident light L is incident from above each of the red pixel Pr, green pixel Pg, and blue pixel Pb and is collected at approximately the center of each of the color pixels PR, Pg, and Pb. Therefore, in each of the red pixel Pr, green pixel Pg, and blue pixel Pb arranged in the central portion A of the pixel array unit 100A, as shown in FIG. 60A , the first separation portion 94A is provided at a position that divides the pixel approximately equally in the X-axis direction, and the gap G1 between the pair of protrusions 94A1 and 94A2 is formed approximately in the center of the pixel.

[0272] For example, at position B1 to the right of the center A of the pixel array unit 100A, incident light L is incident on the red pixel Pr, the green pixel Pg, and the blue pixel Pb from an oblique direction. At this time, the light (red light, green light, and blue light) transmitted through the on-chip lens 25L and the color filters 24R, 24G, and 24B corresponding to the color pixels Pr, Pg, and Pb shifts its focusing position in the X-axis direction according to its wavelength. Specifically, green light is focused at approximately the center of the pixel by the pupil-corrected on-chip lens 25L, whereas red light, which has a longer wavelength than green light, is focused at a position shifted to the right (toward the periphery of the pixel array unit 100A) from approximately the center of the pixel. Blue light, which has a shorter wavelength than green light, is focused at a position shifted to the left (toward the center of the pixel array unit 100A) from approximately the center of the pixel.

[0273] 60B , in the red pixel Pr disposed at position B1 to the right of the center A of the pixel array unit 100A, the gap G1 between the pair of protrusions 94A1 and 94A2 is formed approximately in the center of the pixel, but the first isolation portion 94A is provided at a position shifted to the right (toward the outer periphery of the pixel array unit 100A) from the position that divides the pixel equally in the X-axis direction. In the blue pixel Pb disposed at position B1 to the right of the center A of the pixel array unit 100A, the gap G1 between the pair of protrusions 94A1 and 94A2 is formed approximately in the center of the pixel, but the first isolation portion 94A is provided at a position shifted to the left (toward the center of the pixel array unit 100A) from the position that divides the pixel equally in the X-axis direction.

[0274] For example, at position C1 below the center A of the pixel array unit 100A, similar to position B1, incident light L is incident on the red pixel Pr, green pixel Pg, and blue pixel Pb from an oblique direction. At this time, the light (red light, green light, and blue light) transmitted through the on-chip lens 25L and the color filters 24R, 24G, and 24B corresponding to the color pixels Pr, Pg, and Pb shifts its focusing position in the Y-axis direction according to its wavelength. Specifically, green light is focused at approximately the center of the pixel by the pupil-corrected on-chip lens 25L, whereas red light, which has a longer wavelength than green light, is focused at a position shifted downward (toward the periphery of the pixel array unit 100A) from the approximately center of the pixel. Blue light, which has a shorter wavelength than green light, is focused at a position shifted upward (toward the center of the pixel array unit 100A) from the approximately center of the pixel.

[0275] 60C , in the red pixel Pr disposed at position C1 downward from the center A of the pixel array unit 100A, the first separation portion 94A is formed at a position that divides the pixel equally in the X-axis direction, but the gap G1 between the pair of protrusions 94A1, 94A2 is formed at a position shifted downward (toward the outer periphery of the pixel array unit 100A) from approximately the center of the pixel. In other words, of the pair of protrusions 94A1, 94A2, the protrusion 94A1 of the red pixel Pr protrudes more than the protrusion 94A1 of the green pixel Pg, whereas the protrusion 94A2 of the red pixel Pr protrudes less than the protrusion 94A2 of the green pixel Pg. 60C , in the blue pixel Pb arranged at position C1 below the center A of the pixel array unit 100A, the first separation portion 94A is formed at a position that divides the pixel equally in the X-axis direction, but the gap G1 between the pair of protrusions 94A1, 94A2 is formed at a position shifted upward (toward the center of the pixel array unit 100A) from approximately the center of the pixel. In other words, of the pair of protrusions 94A1, 94A2, the protrusion 94A1 of the blue pixel Pb protrudes less than the protrusion 94A1 of the green pixel Pg, whereas the protrusion 94A2 of the blue pixel Pb protrudes more than the protrusion 94A2 of the green pixel Pg.

[0276] For example, at position D1, which is diagonally downward with respect to the center A of the pixel array unit 100A, the incident light L is incident on the red pixel Pr, the green pixel Pg, and the blue pixel Pb from the diagonal direction, similar to positions B1 and C1. At this time, the light (red light, green light, and blue light) transmitted through the on-chip lens 25L and the color filters 24R, 24G, and 24B corresponding to the color pixels Pr, Pg, and Pb shifts its focusing position in the X-axis direction and the Y-axis direction according to its wavelength. Specifically, the green light is focused at approximately the center of the pixel by the pupil-corrected on-chip lens 25L, whereas the red light, which has a longer wavelength than the green light, is focused at a position shifted diagonally downward (toward the periphery of the pixel array unit 100A) from approximately the center of the pixel. The blue light, which has a shorter wavelength than the green light, is focused at a position shifted diagonally upward (toward the center of the pixel array unit 100A) from approximately the center of the pixel.

[0277] 60D , in the red pixel Pr disposed at position D1 diagonally downward with respect to the center A of the pixel array unit 100A, the first separation portion 94A is provided at a position shifted rightward (toward the periphery of the pixel array unit 100A) from the position that divides the pixel equally in the X-axis direction, and the gap G1 between the pair of protrusions 94A1 and 94A2 is formed at a position shifted downward (toward the periphery of the pixel array unit 100A) from approximately the center of the pixel. In the blue pixel Pb disposed at position D1 diagonally downward with respect to the center A of the pixel array unit 100A, the first separation portion 94A is provided at a position shifted leftward (toward the center of the pixel array unit 100A) from the position that divides the pixel equally in the X-axis direction, and the gap G1 between the pair of protrusions 94A1 and 94A2 is formed at a position shifted upward (toward the center of the pixel array unit 100A) from approximately the center of the pixel.

[0278] The first separation portion 94A provided in the green pixel Pg is provided at a position that divides the pixel approximately evenly in the X-axis direction, regardless of its position within the pixel array portion 100A, and the gap G1 between the pair of protrusions 94A1, 94A2 is formed approximately in the center of the pixel.

[0279] Furthermore, the red pixel Pr and blue pixel Pb arranged at position B2 to the left of the center A of the pixel array unit 100A have a structure obtained by flipping the configuration shown in FIG. 60B from side to side. The red pixel Pr and blue pixel Pb arranged at position C2 above the center A of the pixel array unit 100A have a structure obtained by flipping the configuration shown in FIG. 60C from side to side. The red pixel Pr and blue pixel Pb arranged at position D2 diagonally downward and to the left of the center A of the pixel array unit 100A have a structure obtained by flipping the configuration shown in FIG. 60D from side to side. The red pixel Pr and blue pixel Pb arranged at position D3 diagonally upward and to the right of the center A of the pixel array unit 100A have a structure obtained by flipping the configuration shown in FIG. 60D from side to side. The red pixel Pr and blue pixel Pb arranged at position D4 diagonally upward and to the left of the center A of the pixel array unit 100A have a structure obtained by flipping the configuration shown in FIG. 60D from side to side.

[0280] [Actions and Effects] For example, in a photodetector device in which adjacent photoelectric conversion units within a pixel are separated by a so-called plug-in structure, the plug-in structure of each pixel has the same shape regardless of its position within the pixel array unit or the detected wavelength.

[0281] In addition, in a typical photodetector, pupil correction is performed according to the image height by correcting the focal point of the incident light by shifting the positions of the on-chip lens and color filter in a predetermined direction. The amount of correction is generally set based on the pixel that detects green light (G pixel).

[0282] However, in reality, as described above, the light-collecting points at each RGB pixel differ depending on the wavelength of the collected light, which causes a difference in sensitivity between the left and right RGB pixels. As a result, the phase difference is not detected correctly, and there is a problem that the focus shifts depending on the color of the subject.

[0283] One possible way to solve this problem is to change the amount of shifting of the on-chip lens or color filter for each RGB pixel. However, in this case, there is a concern that gaps will be generated between the lenses and filters, which could result in a decrease in sensitivity or worsening color mixing.

[0284] In contrast, in the photodetector 6, the configuration of the first separator 94A is varied depending on the position of the pixel arranged in the pixel array unit 100A and the wavelength to be detected, as described above. Specifically, the focusing positions of the light of each wavelength (red light, green light, and blue light) focused on the red pixel Pr, green pixel Pg, and blue pixel Pb are approximately aligned with the position of the gap G1 between the pair of protrusions 94A1 and 94A2 provided on each pixel. This makes it possible to align the outputs of the left and right pixels in response to incident light at the principal ray angle in all unit pixels P arranged in the pixel array unit 100A. In other words, the phase difference can be accurately acquired in the red pixel Pr and blue pixel Pb, thereby improving phase-difference autofocus performance.

[0285] As described above, the photodetector 6 of this embodiment can further improve the phase difference detection performance compared to the photodetector 1 of the first embodiment.

[0286] 63A is a schematic plan view illustrating an example of the shape of the second separation portions 94B of the red pixels Pr, green pixels Pg, and blue pixels Pb at the center A (see FIG. 59 ) of the pixel array unit 100A of a photodetector (photodetector 6A) according to Modification 20 of the present disclosure. FIG. 63B is a schematic plan view illustrating an example of the shape of the second separation portions 94B of the red pixels Pr, green pixels Pg, and blue pixels Pb at a position B1 (see FIG. 59 ) to the right of the center A of the pixel array unit 100A. FIG. 63C is a schematic plan view illustrating an example of the shape of the second separation portions 94B of the red pixels Pr, green pixels Pg, and blue pixels Pb at a position C1 (see FIG. 59 ) below the center A of the pixel array unit 100A. 63D is a schematic plan view showing an example of the shape of the second isolation portion 94B of the red pixel Pr, the green pixel Pg, and the blue pixel Pb at a position D1 (see FIG. 59 ) diagonally downward to the right with respect to the center A of the pixel array unit 100A. Like the photodetector 1 of the first embodiment, the photodetector 6A is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0287] Although the sixth embodiment described above illustrates an example in which phase difference information in the left-right direction is acquired, this is not limiting. The photodetector 6A of this modified example acquires phase difference information in the up-down direction, and includes an inter-element separator 94, a second separator 94B, which is provided between a plurality of photoelectric conversion units 12 adjacent to each other in the Y-axis direction within a pixel and is composed of a pair of protrusions 94B1 and 94B2 that protrude toward the center of the pixel from a pair of sides of the inter-pixel separator 93 facing each other in the X-axis direction. A gap G2 is provided between the protrusions 94B1 and 94B2. Except for this point, the photodetector 6A has substantially the same configuration as the photodetector 6 of the sixth embodiment described above.

[0288] Here, the second separation portion 94B corresponds to a specific example of a "second separation portion" as one embodiment of the present disclosure, and the pair of protrusions 94B1, 94B2 correspond to a specific example of a "pair of second protrusions" as one embodiment of the present disclosure.

[0289] As described above, the second isolation portion 94B extends from a pair of sides of the inter-pixel isolation portion 93 facing each other in the X-axis direction to just before the center of the pixel, and is composed of a pair of protrusions 94B1 and 94B2 that separate the photoelectric conversion portion 12-1 and the photoelectric conversion portion 12-2 that are adjacent in the Y-axis direction, with a gap G2 between the protrusions 94B1 and 94B2. In the photodetector 6A, by providing the inter-element isolation portion 94 that separates the two photoelectric conversion portions 12-1 and 12-2 arranged in two rows and one column from each other, it is possible to acquire phase difference information in the left-right direction in one unit pixel P.

[0290] In the photodetector 6A, the positions at which the pair of protrusions 94B1, 94B2 constituting the second separation section 94B are formed in the X-axis direction within the pixel, and the position of the gap G2 within the pixel are configured to differ from each other depending on the position at which they are arranged within the pixel array section 100A and the wavelength to be detected.

[0291] For example, in each of the red pixel Pr, green pixel Pg, and blue pixel Pb arranged in the center A of the pixel array section 100A, as shown in Figure 63A, the second separation section 94B is provided at a position that divides the pixel approximately evenly in the Y-axis direction, and the gap G2 between the pair of protrusions 94B1, 94B2 is formed approximately in the center of the pixel.

[0292] For example, in a red pixel Pr disposed at a position B1 to the right of the center A of the pixel array unit 100A, as shown in Fig. 63B , the second separation portion 94B is formed at a position that divides the pixel equally in the Y-axis direction, but the gap G2 between the pair of protrusions 94B1, 94B2 is formed at a position shifted to the right (toward the outer periphery of the pixel array unit 100A) from approximately the center of the pixel. In a blue pixel Pb disposed at a position B1 to the right of the center A of the pixel array unit 100A, as shown in Fig. 63B , the second separation portion 94B is formed at a position that divides the pixel equally in the X-axis direction, but the second separation portion 94B is provided at a position shifted to the left (toward the center of the pixel array unit 100A) from the position that divides the pixel equally in the X-axis direction.

[0293] For example, in a red pixel Pr disposed at a position C1 below the center A of the pixel array unit 100A, as shown in Fig. 63C, the gap G2 between the pair of protrusions 94B1 and 94B2 is formed approximately in the center of the pixel, but the second separation portion 94B is provided at a position shifted downward (toward the outer periphery of the pixel array unit 100A) from the position that divides the pixel equally in the Y-axis direction. In a blue pixel Pb disposed at a position C1 below the center A of the pixel array unit 100A, as shown in Fig. 63C, the gap G2 between the pair of protrusions 94B1 and 94B2 is formed approximately in the center of the pixel, but the second separation portion 94B is provided at a position shifted upward (toward the center of the pixel array unit 100A) from the position that divides the pixel equally in the X-axis direction.

[0294] For example, in a red pixel Pr disposed at a position D1 diagonally downward with respect to the center A of the pixel array unit 100A, the second separation portion 94B is provided at a position shifted downward (toward the periphery of the pixel array unit 100A) from a position that divides the pixel equally in the Y-axis direction, and the gap G2 between the pair of protrusions 94B1 and 94B2 is formed at a position shifted rightward (toward the periphery of the pixel array unit 100A) from approximately the center of the pixel, as shown in Fig. 63D . In a blue pixel Pb disposed at a position D1 diagonally downward with respect to the center A of the pixel array unit 100A, the second separation portion 94B is provided at a position shifted upward (toward the center of the pixel array unit 100A) from a position that divides the pixel equally in the Y-axis direction, and the gap G2 between the pair of protrusions 94B1 and 94B2 is formed at a position shifted leftward (toward the center of the pixel array unit 100A) from approximately the center of the pixel, as shown in Fig. 63D .

[0295] As in the sixth embodiment, the second separation portion 94B provided in the green pixel Pg is provided at a position that divides the pixel approximately equally in the Y-axis direction, regardless of its position within the pixel array portion 100A, and the gap G2 between the pair of protrusions 94B1, 94B2 is formed approximately in the center of the pixel.

[0296] Furthermore, the red pixel Pr and blue pixel Pb arranged at position B2 to the left of the center A of the pixel array unit 100A have a structure obtained by flipping the configuration shown in FIG. 63B from side to side. The red pixel Pr and blue pixel Pb arranged at position C2 above the center A of the pixel array unit 100A have a structure obtained by flipping the configuration shown in FIG. 63C from side to side. The red pixel Pr and blue pixel Pb arranged at position D2 diagonally downward and to the left of the center A of the pixel array unit 100A have a structure obtained by flipping the configuration shown in FIG. 63D from side to side. The red pixel Pr and blue pixel Pb arranged at position D3 diagonally upward and to the right of the center A of the pixel array unit 100A have a structure obtained by flipping the configuration shown in FIG. 63D from side to side. The red pixel Pr and blue pixel Pb arranged at position D4 diagonally upward and to the left of the center A of the pixel array unit 100A have a structure obtained by flipping the configuration shown in FIG. 63D from side to side.

[0297] (11-2. Modification 21) FIG. 64A is a schematic plan view illustrating an example of the shapes of the first separation portions of the red pixel Pr, the green pixel Pg, and the blue pixel Pb at the center A (see FIG. 59 ) of the pixel array unit 100A of a photodetector (photodetector device 6B) according to Modification 21 of the present disclosure. FIG. 64B is a schematic plan view illustrating an example of the shapes of the first separation portions of the red pixel Pr, the green pixel Pg, and the blue pixel Pb at a position B1 (see FIG. 59 ) to the right of the center A of the pixel array unit 100A. FIG. 64C is a schematic plan view illustrating an example of the shapes of the first separation portions of the red pixel Pr, the green pixel Pg, and the blue pixel Pb at a position C1 (see FIG. 59 ) below the center A of the pixel array unit 100A. FIG. 64D is a schematic plan view illustrating an example of the shapes of the first separation portions of the red pixel Pr, the green pixel Pg, and the blue pixel Pb at a position D1 (see FIG. 59 ) diagonally downward to the right of the center A of the pixel array unit 100A. The photodetector 6B is, like the photodetector 1 of the first embodiment, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0298] A photodetector 6B of this modification is a combination of the sixth embodiment and modification 20, and has, as inter-element isolation portions 94, a first isolation portion 94A provided between a plurality of photoelectric conversion portions 12 adjacent in the X-axis direction and the Y-axis direction within a pixel, and consisting of a pair of protrusions 94A1 and 94A2 that respectively protrude from a pair of sides of the inter-pixel isolation portion 93 that face each other in the Y-axis direction toward the center of the pixel, and a second isolation portion 94B that is a pair of protrusions 94B1 and 94B2 that respectively protrude from a pair of sides of the inter-pixel isolation portion 93 that face each other in the X-axis direction toward the center of the pixel. Gaps G are formed between the intersecting protrusions 94A1 and 94A2 and between the intersecting protrusions 94B1 and 94B2.

[0299] The photodetector 6B can obtain phase difference information in all directions from one unit pixel.

[0300] As described above, in the photodetector 6B of this modification, the configurations of the pair of protrusions 94A1 and 94A2 that constitute the first separation unit 94A and the pair of protrusions 94B1 and 94B2 that constitute the second separation unit 94B are made different depending on the position of the pixel arranged in the pixel array unit 100A and the wavelength to be detected. As a result, in this modification, it is possible to provide a photodetector 6B that has high imaging performance and further improved phase difference detection performance in all directions.

[0301] (11-3. Modification 22) Figure 65 is a schematic diagram illustrating an example of a planar configuration of red pixels Pr, green pixels Pg, and blue pixels Pb of a photodetector (photodetector 6C) according to Modification 22 of the present disclosure. Figure 66 is a schematic diagram illustrating an example of a cross-sectional configuration of red pixels Pr, green pixels Pg, and blue pixels Pb corresponding to line XXII-XXII' shown in Figure 65. Like the photodetector 1 of the first embodiment, the photodetector 6C is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0302] In the photodetector 6C of this modification, the thickness of the first isolation portion 94A, which is made up of a pair of protrusions 94A1 and 94A2, in the in-plane direction of the semiconductor substrate 11 varies in the thickness direction (Z-axis direction) of the semiconductor substrate 11, and the variation in thickness differs among the red pixel Pr, the green pixel Pg, and the blue pixel Pb. Except for this point, the photodetector 6C has substantially the same configuration as the photodetector 6 of the sixth embodiment.

[0303] Even with this configuration, the photodetector 6C of this modified example can obtain the same effects as those of the sixth embodiment.

[0304] Furthermore, in the photodetector 6C of this modification, in the red pixel Pr and the blue pixel Pb, the thickness of the first isolation portion 94A in the in-plane direction of the semiconductor substrate 11 increases from the light incident surface (second surface 11S2) to the element formation surface (first surface 11S1) toward the center of the pixel. This reduces the volume difference between the adjacent photoelectric conversion units 12-1 and 12-2 in each of the red pixel Pr and the blue pixel Pb, and therefore makes it possible to bring the output ratio between the adjacent photoelectric conversion units 12-1 and 12-2 closer to 1:1.

[0305] (11-4. Modification 23) Fig. 67 is a schematic diagram illustrating an example of a planar configuration of red pixels Pr, green pixels Pg, and blue pixels Pb of a photodetector (photodetector 6D) according to Modification 23 of the present disclosure. Fig. 68 is a schematic diagram illustrating an example of a cross-sectional configuration of the red pixels Pr, green pixels Pg, and blue pixels Pb corresponding to line XXIII-XXIII' shown in Fig. 67. Like the photodetector 1 of the first embodiment, the photodetector 6D is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0306] In the photodetector 6D of this modification, the extension directions of the first isolation portion 94A, which is made up of a pair of protrusions 94A1 and 94A2, from the light incident surface (second surface 11S2) side of the semiconductor substrate 11 to the element forming surface (first surface 11S1) side are different among the red pixel Pr, the green pixel Pg, and the blue pixel Pb. Except for this point, the photodetector 6D has substantially the same configuration as the photodetector 6 of the sixth embodiment.

[0307] Even with this configuration, the photodetector 6D of this modified example can obtain the same effects as those of the sixth embodiment.

[0308] Furthermore, in the photodetector device 6D of this modification, in the red pixel Pr and the blue pixel Pb, the first separator 94A extends from the light incident surface (second surface 11S2) side toward the element formation surface (first surface 11S1) side of the semiconductor substrate 11 toward the center of the pixel from positions corresponding to the respective focusing points of the red light and the blue light. As in the above modification 22, this reduces the volume difference between the adjacent photoelectric conversion units 12-1 and 12-2 in each of the red pixel Pr and the blue pixel Pb, and therefore makes it possible to bring the output ratio between the adjacent photoelectric conversion units 12-1 and 12-2 closer to 1:1.

[0309] (11-5. Modification 24) Fig. 69 is a schematic diagram illustrating an example of the planar configuration of the light incident surface (second surface 11S2) side (A) and the element formation surface (first surface 11S1) side (B) of the red pixel Pr, green pixel Pg, and blue pixel Pb of a photodetector (photodetector 6E) according to Modification 24 of the present disclosure. Fig. 70 is a schematic diagram illustrating an example of the cross-sectional configuration of the red pixel Pr, green pixel Pg, and blue pixel Pb corresponding to the line XXIV-XXIV' shown in Fig. 69. The photodetector 6E is, like the photodetector 1 of the first embodiment, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0310] In the photodetector 6E of this modification, the protrusion amounts of a pair of protrusions 94A1, 94A2 are different between the red pixel Pr, the green pixel Pg, and the blue pixel Pb on the light incident surface (second surface 11S2) side, but are the same between the red pixel Pr, the green pixel Pg, and the blue pixel Pb on the element forming surface (first surface 11S1) side. Except for this point, the photodetector 6E has substantially the same configuration as the photodetector 6 of the sixth embodiment.

[0311] Even with this configuration, the photodetector 6E of this modified example can obtain the same effects as those of the sixth embodiment.

[0312] Furthermore, in the photodetector 6E of this modified example, the protrusion amounts of the pairs of protrusions 94A1, 94A2 on the element formation surface (first surface 11S1) side of the red pixel Pr, green pixel Pg, and blue pixel Pb are set to be approximately the same, so that the structure of the semiconductor substrate 11 on the element formation surface (first surface 11S1) side is unified for all unit pixels P. This facilitates the wiring design on the first surface 11S1.

[0313] (11-6. Modification 25) FIG. 71 is a schematic diagram illustrating an example of the planar configuration of the light incident surface (second surface 11S2) side (A) and the element formation surface (first surface 11S1) side (B) of the red pixel Pr, green pixel Pg, and blue pixel Pb of a photodetector (photodetector 6F) according to Modification 25 of the present disclosure. FIG. 72 is a schematic diagram illustrating an example of the cross-sectional configuration of the red pixel Pr, green pixel Pg, and blue pixel Pb corresponding to the line XXV-XXV′ shown in FIG. 71 . Like the photodetector 1 of the first embodiment, the photodetector 6F is, for example, a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and is, for example, a so-called back-illuminated photodetector.

[0314] In the photodetector 6F of this modification, the opposing side surfaces of the pair of protrusions 94A1, 94A2 are inclined, widening the gap G1 from the light incident surface (second surface 11S2) side toward the element formation surface (first surface 11S1) side of the semiconductor substrate 11. Except for this point, the photodetector 6F has substantially the same configuration as the photodetector 6 of the sixth embodiment.

[0315] Even with this configuration, the photodetector 6F of this modified example can obtain the same effects as those of the sixth embodiment.

[0316] Furthermore, in the photodetector 6F of this modified example, the p-type diffusion region 121 can be formed in a self-aligned manner in the step of forming the element isolation portion 94, so that the step of forming the overflow path OFP can be eliminated.

[0317] <12. Application Examples> (Application Example 1) The above-described light detection device 1 and the like can be applied to any type of electronic device with an imaging function, for example, a camera system such as a digital still camera or a video camera, a mobile phone with an imaging function, etc. Fig. 53 shows a schematic configuration of an electronic device 1000.

[0318] The electronic device 1000 includes, for example, a lens group 1001, a photodetector 1, a DSP (Digital Signal Processor) circuit 1002, a frame memory 1003, a display unit 1004, a memory unit 1005, an operation unit 1006, and a power supply unit 1007, which are interconnected via a bus line 1008.

[0319] The lens group 1001 takes in incident light (image light) from a subject and forms an image on the imaging surface of the photodetector 1. The photodetector 1 converts the amount of incident light formed on the imaging surface by the lens group 1001 into an electrical signal on a pixel-by-pixel basis and supplies the signal as a pixel signal to the DSP circuit 1002.

[0320] The DSP circuit 1002 is a signal processing circuit that processes signals supplied from the photodetector 1. The DSP circuit 1002 outputs image data obtained by processing the signals from the photodetector 1. The frame memory 1003 temporarily stores the image data processed by the DSP circuit 1002 on a frame-by-frame basis.

[0321] The display unit 1004 is composed of a panel-type display device such as a liquid crystal panel or an organic EL (Electro Luminescence) panel, and the memory unit 1005 records image data of moving or still images captured by the photodetector 1 on a recording medium such as a semiconductor memory or a hard disk.

[0322] In response to a user's operation, the operation unit 1006 outputs operation signals for various functions of the electronic device 1000. The power supply unit 1007 supplies various types of power to the DSP circuit 1002, frame memory 1003, display unit 1004, storage unit 1005, and operation unit 1006 as needed.

[0323] (Application Example 2) Fig. 54A schematically illustrates an example of the overall configuration of a light detection system 2000 including a light detection device (e.g., light detection device 1). Fig. 54B illustrates an example of the circuit configuration of the light detection system 2000. The light detection system 2000 includes a light emitting device 2001 serving as a light source unit that emits infrared light L2, and a light detection device 2002 serving as a light receiving unit. The light detection device 2002 may be, for example, the light detection device 1 described above. The light detection system 2000 may further include a system control unit 2003, a light source driving unit 2004, a sensor control unit 2005, a light source side optical system 2006, and a camera side optical system 2007.

[0324] The photodetector 2002 can detect light L1 and light L2. Light L1 is external ambient light reflected by the object (measurement target) 2100 ( FIG. 54A ). Light L2 is light emitted by the light-emitting device 2001 and then reflected by the object 2100. Light L1 is, for example, visible light, and light L2 is, for example, infrared light. Light L1 can be detected by a photoelectric conversion unit in the photodetector 2002, and light L2 can be detected by a photoelectric conversion region in the photodetector 2002. Image information of the object 2100 can be obtained from light L1, and distance information between the object 2100 and the photodetector system 2000 can be obtained from light L2. The photodetector system 2000 can be installed in, for example, an electronic device such as a smartphone or a mobile object such as a car. The light-emitting device 2001 can be configured, for example, by a semiconductor laser, a surface-emitting semiconductor laser, or a vertical-cavity surface-emitting laser (VCSEL). The method of detecting the light L2 emitted from the light-emitting device 2001 by the photodetector 2002 can be, for example, an iTOF method, but is not limited to this. In the iTOF method, the photoelectric conversion unit can measure the distance to the subject 2100, for example, by using the time-of-flight (TOF) of light. The method of detecting the light L2 emitted from the light-emitting device 2001 by the photodetector 2002 can also be, for example, a structured light method or a stereo vision method. For example, in the structured light method, a predetermined pattern of light is projected onto the subject 2100, and the distance between the photodetector system 2000 and the subject 2100 can be measured by analyzing the distortion of the pattern. In addition, in the stereo vision method, for example, two or more cameras are used to acquire two or more images of the subject 2100 viewed from two or more different viewpoints, thereby measuring the distance between the photodetector system 2000 and the subject. The light emitting device 2001 and the light detecting device 2002 can be controlled synchronously by a system control unit 2003 .

[0325] 13. Application Examples (Application Examples to Mobile Bodies) The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0326] FIG. 55 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology of the present disclosure can be applied.

[0327] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 55, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053.

[0328] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0329] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0330] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0331] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0332] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0333] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0334] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0335] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0336] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to vehicle occupants or the outside of the vehicle. In the example of Fig. 55, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0337] FIG. 56 is a diagram showing an example of the installation position of the imaging unit 12031.

[0338] In FIG. 56 , a vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as the imaging unit 12031.

[0339] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The forward images acquired by the imaging units 12101 and 12105 are mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0340] 56 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0341] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0342] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which runs autonomously without relying on driver operation.

[0343] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0344] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0345] The foregoing has described an example of a mobile object control system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the imaging unit 12031 of the above-described configuration. Specifically, the imaging device 100 can be applied to the imaging unit 12031. By applying the technology according to the present disclosure to the imaging unit 12031, it is possible to obtain high-resolution captured images with little noise, thereby enabling high-precision control using the captured images in the mobile object control system.

[0346] (Application Example to Endoscopic Surgery System) The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0347] FIG. 57 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

[0348] Figure 57 shows an operator (doctor) 11131 performing surgery on a patient 11132 on a patient bed 11153 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0349] The endoscope 11100 is composed of a lens barrel 11101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the example shown, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible scope having a flexible lens barrel.

[0350] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens toward an object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0351] An optical system and an image sensor are provided inside the camera head 11102, and light reflected from the object of observation (observation light) is collected by the optical system onto the image sensor. The observation light is photoelectrically converted by the image sensor to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is sent to a camera control unit (CCU) 11201 as RAW data.

[0352] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and comprehensively controls the operations of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102 and performs various types of image processing on the image signal, such as development processing (demosaic processing), to display an image based on the image signal.

[0353] Under the control of the CCU 11201, the display device 11202 displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

[0354] The light source device 11203 is composed of a light source such as an LED (Light Emitting Diode), and supplies the endoscope 11100 with irradiation light when photographing the surgical site, etc.

[0355] The input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) of the endoscope 11100.

[0356] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 inflates the body cavity of the patient 11132 through the insufflation tube 11111 in order to ensure a clear field of view for the endoscope 11100 and a working space for the surgeon. The recorder 11207 is a device capable of recording various types of information related to the surgery. The printer 11208 is a device capable of printing various types of information related to the surgery in various formats such as text, images, or graphs.

[0357] The light source device 11203, which supplies illumination light to the endoscope 11100 when photographing the surgical site, can be configured from a white light source, such as an LED, a laser light source, or a combination of these. When the white light source is configured from a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, allowing the light source device 11203 to adjust the white balance of the captured image. In this case, it is also possible to time-share images corresponding to each RGB by irradiating the object of observation with laser light from each RGB laser light source and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, color images can be obtained without providing a color filter to the image sensor.

[0358] Furthermore, the light source device 11203 may be controlled to change the intensity of light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity to acquire images in a time-division manner and combining the images, it is possible to generate an image with a high dynamic range that is free from so-called blocked-up shadows and blown-out highlights.

[0359] The light source device 11203 may also be configured to supply light in a predetermined wavelength band corresponding to special light observation. Special light observation, for example, utilizes the wavelength dependence of light absorption in body tissues to irradiate light in a narrower band than the light irradiated during normal observation (i.e., white light) to capture high-contrast images of specific tissues, such as blood vessels on the surface of mucous membranes, in what is known as narrow band imaging. Alternatively, special light observation may involve fluorescence observation, in which images are obtained using fluorescence generated by irradiating excitation light. Fluorescence observation may involve irradiating excitation light onto body tissues and observing the fluorescence from the tissues (autofluorescence observation), or may involve locally injecting a reagent such as indocyanine green (ICG) into the body tissue and irradiating the tissues with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 11203 may be configured to supply narrow band light and / or excitation light corresponding to such special light observation.

[0360] FIG. 58 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0361] The camera head 11102 has a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 has a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 so that they can communicate with each other.

[0362] The lens unit 11401 is an optical system provided at the connection portion with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses including a zoom lens and a focus lens.

[0363] The imaging unit 11402 is composed of an imaging element. The imaging element constituting the imaging unit 11402 may be a single (so-called single-chip type) or multiple (so-called multi-chip type). When the imaging unit 11402 is composed of a multi-chip type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining these signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to 3D (dimensional) display. The 3D display allows the surgeon 11131 to more accurately grasp the depth of the biological tissue at the surgical site. Note that when the imaging unit 11402 is composed of a multi-chip type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0364] Furthermore, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the lens barrel 11101, immediately after the objective lens.

[0365] The driving unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted appropriately.

[0366] The communication unit 11404 is configured by a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0367] Furthermore, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201 and supplies the control signal to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of imaging, and / or information specifying the magnification and focus of the captured image.

[0368] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by the user, or may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0369] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 via the communication unit 11404 .

[0370] The communication unit 11411 is configured by a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0371] Furthermore, the communication unit 11411 transmits to the camera head 11102 a control signal for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

[0372] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0373] The control unit 11413 performs various controls related to the imaging of the surgical site, etc. by the endoscope 11100 and the display of the captured image obtained by imaging the surgical site, etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0374] Furthermore, the control unit 11413 displays the captured image showing the surgical site, etc., on the display device 11202 based on the image signal subjected to image processing by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition technologies. For example, the control unit 11413 can recognize surgical tools such as forceps, specific biological parts, bleeding, mist generated when using the energy treatment tool 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When displaying the captured image on the display device 11202, the control unit 11413 may use the recognition results to superimpose various surgical support information on the image of the surgical site. By superimposing the surgical support information and presenting it to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

[0375] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for electrical signal communication, an optical fiber for optical communication, or a composite cable of these.

[0376] In the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0377] The above describes an example of an endoscopic surgery system to which the technology according to the present disclosure can be applied. Of the configurations described above, the technology according to the present disclosure can be suitably applied to the imaging unit 11402 provided in the camera head 11102 of the endoscope 11100. By applying the technology according to the present disclosure to the imaging unit 11402, it is possible to reduce the size or increase the resolution of the imaging unit 11402, thereby providing a compact or high-resolution endoscope 11100.

[0378] Although the present disclosure has been described above with reference to the first to sixth embodiments, modifications 1 to 25, and application examples, the present technology is not limited to the above-described embodiments, etc., and various modifications are possible. For example, the components constituting the photodetector (photodetector 1) of the above-described embodiments, etc. may be omitted as appropriate, or other components may be provided.

[0379] The effects described in this specification are merely examples and are not limited to those described, and other effects may also be obtained.

[0380] The present disclosure may also be configured as follows. According to the present technology configured as follows, it is easy to control the potential of the overflow path in each of a first direction and a second direction. Therefore, it is possible to achieve both high imaging performance and phase difference detection performance. (1) A photodetector device comprising: a semiconductor substrate having opposing first and second surfaces, in which a plurality of pixels are arranged in a two-dimensional array, and in which a plurality of photoelectric conversion units adjacent to each other in a first direction and a second direction orthogonal to the first direction are embedded for each pixel; an inter-pixel isolation portion embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and an inter-element isolation portion embedded in the semiconductor substrate, the inter-element isolation portion including a first isolation portion provided between the plurality of photoelectric conversion units adjacent to each other in the first direction and a second isolation portion provided between the plurality of photoelectric conversion units adjacent to each other in the second direction, wherein at least one of the first isolation portion and the second isolation portion has a gap between itself and the inter-pixel isolation portion. (2) The photodetector according to (1), wherein the first isolation portion and the second isolation portion each have the gap between themselves and the inter-pixel isolation portion and intersect with each other approximately at the center of the pixel. (3) The photodetector according to (2), wherein the first isolation portion extends in the second direction and has a first gap between itself and the inter-pixel isolation portion at both ends as the gap, the second isolation portion extends in the first direction and has a second gap between itself and the inter-pixel isolation portion at both ends as the gap, and the lengths of the first gap and the second gap are different from each other. (4) The photodetector according to (2) or (3), wherein the first isolation portion extends in the second direction, the second isolation portion extends in the first direction, and the widths of the first isolation portion in the lateral direction and the widths of the second isolation portion in the lateral direction are different from each other.(5) The photodetector according to any one of (2) to (4), further comprising: a first overflow path provided on the first surface of the semiconductor substrate between the first isolation portion and the inter-pixel isolation portion, for exchanging saturated charge between the plurality of photoelectric conversion portions adjacent in the first direction; and a second overflow path provided on the first surface of the semiconductor substrate between the second isolation portion and the inter-pixel isolation portion, for exchanging saturated charge between the plurality of photoelectric conversion portions adjacent in the second direction. (6) The photodetector according to (5), further comprising: a first gate electrode provided on the first surface side of the semiconductor substrate, for controlling a potential of the first overflow path; and a second gate electrode provided on the first surface side of the semiconductor substrate, for controlling a potential of the second overflow path. (7) The photodetector according to (6), wherein the first gate electrode and the second gate electrode are each provided across the inter-pixel isolation portion between adjacent pixels. (8) The photodetector according to any one of (1) to (7), wherein the first isolation portion comprises a pair of protrusions extending from a pair of opposing sides of the inter-pixel isolation portion between the plurality of photoelectric conversion portions adjacent in the first direction to approximately just before the center of the pixel, and the second isolation portion extends in the first direction between the plurality of photoelectric conversion portions adjacent in the second direction and between the pair of protrusions, and has the gap between both ends and the inter-pixel isolation portion. (9) The photodetector according to (8), further comprising: first overflow paths provided between the pair of protrusions and the second isolation portion, respectively, for exchanging saturated charge between the plurality of photoelectric conversion portions adjacent in the first direction; and second overflow paths provided on the first surface of the semiconductor substrate between the second isolation portion and the inter-pixel isolation portion, for exchanging saturated charge between the plurality of photoelectric conversion portions adjacent in the second direction. (10) The photodetector according to any one of (1) to (9), wherein the inter-pixel isolation portion and the inter-element isolation portion are formed by a groove provided in the semiconductor substrate.(11) The photodetector according to (10), wherein the groove is filled with a light-transmitting conductive film, a polysilicon film doped with impurities, or an insulating film. (12) The photodetector according to (11), further comprising a voltage application unit that applies a predetermined voltage to the inter-pixel isolation unit and the inter-element isolation unit formed by filling the conductive film or the polysilicon film. (13) A photodetector device comprising: a semiconductor substrate having opposing first and second surfaces, a plurality of pixels arranged in a two-dimensional array, and a plurality of photoelectric conversion units embedded in each pixel, the photoelectric conversion units being adjacent to each other in a first direction and a second direction perpendicular to the first direction; inter-pixel isolation units embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and inter-element isolation units embedded in the semiconductor substrate, the inter-element isolation units including first isolation units provided between the plurality of photoelectric conversion units adjacent to each other in the first direction and second isolation units provided between the plurality of photoelectric conversion units adjacent to each other in the second direction, the first isolation units having a first bottom within the semiconductor substrate and the second isolation units having a second bottom within the semiconductor substrate, the first bottom and the second bottom being formed at different depths within the semiconductor substrate. (14) The photodetector according to (13), wherein the first isolation portion and the second isolation portion extend from the first surface toward the second surface of the semiconductor substrate, and the first bottom portion and the second bottom portion are respectively provided on the second surface side. (15) The photodetector according to (13) or (14), wherein the first isolation portion and the second isolation portion extend from the second surface toward the first surface of the semiconductor substrate, and the first bottom portion and the second bottom portion are respectively provided on the first surface side. (16) The photodetector according to any one of (13) to (15), wherein the first isolation portion extends from the first surface toward the second surface of the semiconductor substrate, and the second isolation portion extends from the second surface toward the first surface of the semiconductor substrate, and the first bottom portion is provided on the second surface side and the second bottom portion is provided on the first surface side.(17) The photodetector according to any one of (13) to (16), wherein the first isolation portion and the second isolation portion intersect with each other at approximately the center of the pixel. (18) The photodetector according to any one of (13) to (17), wherein one of the first isolation portion and the second isolation portion comprises a pair of protrusions extending from a pair of opposing sides of the inter-pixel isolation portion to approximately just before the center of the pixel between the plurality of photoelectric conversion portions adjacent in the first direction or the second direction, and the other of the first isolation portion and the second isolation portion extends between the pair of protrusions and separates the plurality of photoelectric conversion portions adjacent in the second direction or the first direction. (19) The photodetector according to any one of (13) to (18), wherein the first isolation portion and the second isolation portion are formed by a groove provided in the semiconductor substrate, and the difference in depth between the first bottom portion and the second bottom portion is formed by an impurity diffusion region. (20) A photodetector comprising: a semiconductor substrate having opposing first and second surfaces, in which a plurality of pixels are arranged in a two-dimensional array, and in which a plurality of photoelectric conversion units adjacent to each other in a first direction and a second direction perpendicular to the first direction are embedded for each pixel; inter-pixel isolation units embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and inter-element isolation units embedded in the semiconductor substrate, including first isolation units provided between the plurality of photoelectric conversion units adjacent to each other in the first direction and having a first perimeter in a planar view, and second isolation units provided between the plurality of photoelectric conversion units adjacent to each other in the second direction and having a second perimeter in a planar view, wherein when the first direction is a phase difference acquisition direction and the second direction is a direction other than the phase difference acquisition direction, the second perimeter is shorter than the first perimeter.(21) The photodetector according to (20), wherein the pixel has a substantially square shape consisting of a pair of sides opposing the first direction and a pair of sides opposing the second direction, the first isolation portion comprises a pair of first protrusions extending from each of the pair of sides opposing the second direction of the inter-pixel isolation portion between the plurality of photoelectric conversion units adjacent in the first direction to approximately just before the center of the pixel, the second isolation portion comprises a pair of second protrusions extending from each of the pair of sides opposing the first direction of the inter-pixel isolation portion between the plurality of photoelectric conversion units adjacent in the second direction to approximately just before the center of the pixel, and the longitudinal length of the pair of first protrusions is longer than the longitudinal length of the pair of second protrusions. (22) The photodetector according to (20) or (21), wherein the pixel has a substantially square shape consisting of a pair of sides opposing the first direction and a pair of sides opposing the second direction, the first isolation portion comprises a pair of first protrusions extending from each of the pair of sides opposing the second direction of the inter-pixel isolation portion between the plurality of photoelectric conversion units adjacent in the first direction to approximately just before the center of the pixel, the second isolation portion comprises a pair of second protrusions extending from each of the pair of sides opposing the first direction of the inter-pixel isolation portion between the plurality of photoelectric conversion units adjacent in the second direction to approximately just before the center of the pixel, and the width of the pair of second protrusions in the short side direction is narrower than the width of the pair of first protrusions. (23) The photodetector according to any one of (20) to (22), wherein the pixel has a generally rhombic shape consisting of a pair of vertices opposing each other in the first direction and a pair of vertices opposing each other in the second direction, the first isolation portion is made up of a pair of first protrusions extending from each of the pair of vertices opposing each other in the second direction of the inter-pixel isolation portion between the plurality of photoelectric conversion units adjacent in the first direction to approximately just before the center of the pixel, the second isolation portion is made up of a pair of second protrusions extending from each of the pair of vertices opposing each other in the first direction of the inter-pixel isolation portion between the plurality of photoelectric conversion units adjacent in the second direction to approximately just before the center of the pixel, and the longitudinal length of the pair of first protrusions is longer than the longitudinal length of the pair of second protrusions.(24) The photodetector according to any one of (20) to (23), wherein the pixel has a generally rhombic shape consisting of a pair of vertices facing each other in the first direction and a pair of vertices facing each other in the second direction, the first isolation portion is made up of a pair of first protrusions extending from each of the pair of vertices facing each other in the second direction of the inter-pixel isolation portion to approximately just before the center of the pixel between the plurality of photoelectric conversion units adjacent in the first direction, the second isolation portion is made up of a pair of second protrusions extending from each of the pair of vertices facing each other in the first direction of the inter-pixel isolation portion to approximately just before the center of the pixel between the plurality of photoelectric conversion units adjacent in the second direction, and the width of the pair of second protrusions in the short side direction is narrower than the width of the pair of first protrusions in the short side direction. (25) The photodetector according to any one of (20) to (24), wherein the first isolation portion is a trench provided in the semiconductor substrate and filled with an insulating material, and the second isolation portion is an impurity diffusion region provided in the semiconductor substrate. (26) The photodetector according to any one of (20) to (25), further comprising a plurality of third isolation portions extending from the inter-pixel isolation portion toward approximately the center of the pixel in a direction at approximately 45° with respect to the first direction and the second direction.(27) A semiconductor substrate having opposing first and second surfaces, in which a plurality of pixels are arranged in a two-dimensional array, and in which a plurality of photoelectric conversion units adjacent to each other in a first direction and a second direction orthogonal to the first direction are embedded for each pixel; an inter-pixel isolation unit embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and an inter-element isolation unit embedded in the semiconductor substrate, including: a first isolation unit made of a pair of first protrusions extending from each of a pair of sides of the inter-pixel isolation unit opposing each other in the second direction between the plurality of photoelectric conversion units adjacent to each other in the first direction to approximately just before the center of the pixel; and a second isolation unit made of a pair of second protrusions extending from each of a pair of sides of the inter-pixel isolation unit opposing each other in the first direction between the plurality of photoelectric conversion units adjacent to each other in the second direction to approximately just before the center of the pixel, wherein the pair of first protrusions each have first side surfaces opposing each other in the semiconductor substrate, The photodetector, wherein the pair of second protrusions each have second side surfaces opposing each other in the semiconductor substrate, and the first side surface and the second side surface form different angles with the second surface of the semiconductor substrate. (28) The photodetector according to (27), wherein the spacing between the pair of first protrusions on the first surface side is narrower than the spacing between the pair of first protrusions on the second surface side, and the spacing between the pair of second protrusions on the first surface side is narrower than the spacing between the pair of second protrusions on the second surface side. (29) The photodetector according to (27) or (28), wherein the spacing between the pair of first protrusions on the first surface side is wider than the spacing between the pair of first protrusions on the second surface side, and the spacing between the pair of second protrusions on the first surface side is wider than the spacing between the pair of second protrusions on the second surface side. (30) The optical detection device according to any one of (27) to (29), wherein the spacing between the pair of first protrusions on the first surface side is narrower than the spacing between the pair of first protrusions on the second surface side, and the spacing between the pair of second protrusions on the first surface side is wider than the spacing between the pair of second protrusions on the second surface side.(31) The photodetector according to any one of (27) to (30), wherein the first isolation portion and the second isolation portion are formed by a trench provided in the semiconductor substrate and filled with an insulating material, and an impurity diffusion region provided on a side surface of the trench. (32) A photodetector comprising: a semiconductor substrate having opposing first and second surfaces, a plurality of pixels arranged in a two-dimensional array, and a plurality of photoelectric conversion units adjacent in at least a first direction embedded in each of the pixels; an inter-pixel isolation unit embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and an inter-element isolation unit embedded in the semiconductor substrate, including, within the pixel, a first isolation unit made of a pair of first protrusions extending from each of a pair of sides of the inter-pixel isolation unit opposing in a second direction orthogonal to the first direction toward approximately the center of the pixel between the plurality of photoelectric conversion units adjacent in the first direction, wherein the plurality of pixels include a first pixel and a second pixel having detection wavelengths different from each other, the pair of first protrusions having a first gap therebetween, and the pair of first protrusions provided in the first pixel and the second pixel, respectively, differ from each other in at least one of the formation positions in the first direction within the pixel and the position of the first gap within the pixel. (33) The photodetector according to (32), wherein the plurality of pixels further include a third pixel having a detection wavelength different from that of the first pixel and the second pixel, and the pair of first protrusions provided on the first pixel, the second pixel, and the third pixel, respectively, are different from each other in at least one of the formation positions in the pixel in the first direction and the position of the first gap in the pixel.(34) The photodetector according to (33), wherein the first pixel is a red pixel that detects wavelengths in a red band, the second pixel is a green pixel that detects wavelengths in a green band, and the third pixel is a blue pixel that detects wavelengths in a blue band, wherein the green pixel has the pair of first protrusions formed at positions that divide the pixel approximately evenly in the first direction and the first gap formed at approximately the center of the pixel, and wherein the red pixel and the blue pixel have the pair of first protrusions formed at positions that divide the pixel unevenly in the first direction and the first gap formed at a position shifted from approximately the center of the pixel in a predetermined direction. (35) The photodetector according to any one of (32) to (34), wherein the inter-element isolation portions provided in the first pixel and the second pixel have thicknesses different from each other in an in-plane direction of the semiconductor substrate. (36) The photodetector according to any one of (32) to (35), wherein the first pixel and the second pixel have inter-element isolation portions that extend in different directions between the first surface and the second surface of the semiconductor substrate. (37) The photodetector according to any one of (32) to (36), wherein the pair of first protrusions provided in the first pixel have different protrusion amounts on the first surface side and the second surface side of the semiconductor substrate. (38) The photodetector device according to any one of (32) to (37), wherein the pixel includes the plurality of photoelectric conversion units adjacent in the first direction and the second direction, the inter-element isolation unit further includes a second isolation unit embedded in the semiconductor substrate within the pixel, the second isolation unit including a pair of second protrusions extending from each of a pair of sides of the inter-pixel isolation unit facing each other in the first direction toward approximately the center of the pixel between the plurality of photoelectric conversion units adjacent in the second direction, the pair of second protrusions having a second gap therebetween, and the pair of second protrusions provided in the first pixel and the second pixel, respectively, are different from each other in at least one of the formation positions in the second direction within the pixel and the position of the second gap within the pixel.(39) The photodetector according to any one of (32) to (38), wherein the semiconductor substrate further includes a pixel array section in which the plurality of pixels are arranged in a two-dimensional array, and at least one of positions in the first direction within the pixels of the pair of first protrusions provided in the first pixel and the second pixel, respectively, and a position of the first gap within the pixels are different from each other in a peripheral portion of the pixel array section. (40) The photodetector according to any one of (32) to (39), wherein the first gap approximately coincides with a focusing position of light incident on the first pixel and the second pixel, respectively.

[0381] This application claims priority based on Japanese Patent Application No. 2024-018490, filed on February 9, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0382] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. A photodetector comprising: a semiconductor substrate having opposing first and second surfaces, a plurality of pixels arranged in a two-dimensional array, and a plurality of photoelectric conversion units embedded in each pixel, the photoelectric conversion units being adjacent to each other in a first direction and a second direction perpendicular to the first direction; inter-pixel isolation units embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and inter-element isolation units embedded in the semiconductor substrate, the inter-element isolation units including first isolation units provided between the plurality of photoelectric conversion units adjacent to each other in the first direction and second isolation units provided between the plurality of photoelectric conversion units adjacent to each other in the second direction, and at least one of the first isolation units and the second isolation units having a gap between them and the inter-pixel isolation unit.

2. The photodetector device according to claim 1, wherein the first isolation portion and the second isolation portion each have the gap between them and the inter-pixel isolation portion, and intersect with each other substantially at the center of the pixel.

3. The photodetector device of claim 2, wherein the first separation portion extends in the second direction and has a first gap between itself and the inter-pixel separation portion at both ends as the gap, the second separation portion extends in the first direction and has a second gap between itself and the inter-pixel separation portion at both ends as the gap, and the length of the first gap and the length of the second gap are different from each other.

4. The optical detection device described in claim 2, wherein the first separation portion extends in the second direction, the second separation portion extends in the first direction, and the width of the short side of the first separation portion and the width of the short side of the second separation portion are different from each other.

5. The photodetector device of claim 2, further comprising: a first overflow path provided on the first surface of the semiconductor substrate between the first isolation section and the inter-pixel isolation section, for transferring saturated charges between the plurality of photoelectric conversion sections adjacent in the first direction; and a second overflow path provided on the first surface of the semiconductor substrate between the second isolation section and the inter-pixel isolation section, for transferring saturated charges between the plurality of photoelectric conversion sections adjacent in the second direction.

6. The photodetector device according to claim 5, further comprising: a first gate electrode provided on the first surface side of the semiconductor substrate, for controlling the potential of the first overflow path; and a second gate electrode provided on the first surface side of the semiconductor substrate, for controlling the potential of the second overflow path.

7. The photodetector according to claim 6, wherein the first gate electrode and the second gate electrode are each provided across the inter-pixel isolation portion between adjacent pixels.

8. The photodetector device of claim 1, wherein the first separation section comprises a pair of protrusions extending from each of a pair of opposing sides of the inter-pixel separation section to approximately just before the center of the pixel between the plurality of photoelectric conversion sections adjacent in the first direction, and the second separation section extends in the first direction between the plurality of photoelectric conversion sections adjacent in the second direction and between the pair of protrusions, and has the gap between both ends and the inter-pixel separation section.

9. The photodetector device described in claim 8, further comprising: first overflow paths provided between the pair of protrusions and the second isolation portion, respectively, for transferring saturated charges between the plurality of photoelectric conversion portions adjacent in the first direction; and second overflow paths provided on the first surface of the semiconductor substrate between the second isolation portion and the inter-pixel isolation portion, for transferring saturated charges between the plurality of photoelectric conversion portions adjacent in the second direction.

10. The photodetector according to claim 1, wherein the inter-pixel isolation portion and the inter-element isolation portion are formed by trenches provided in the semiconductor substrate.

11. The photodetector according to claim 10, wherein the groove is filled with a light-transmitting conductive film, a polysilicon film doped with impurities, or an insulating film.

12. The photodetector according to claim 11, further comprising a voltage application section that applies a predetermined voltage to the inter-pixel isolation section and the inter-element isolation section formed by embedding the conductive film or the polysilicon film.

13. A photodetector comprising: a semiconductor substrate having opposing first and second surfaces, a plurality of pixels arranged in a two-dimensional array, and a plurality of photoelectric conversion units embedded in each pixel, the photoelectric conversion units being adjacent to each other in a first direction and a second direction perpendicular to the first direction; inter-pixel isolation units embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and inter-element isolation units embedded in the semiconductor substrate, the inter-element isolation units including a first isolation unit provided between the plurality of photoelectric conversion units adjacent to each other in the first direction and a second isolation unit provided between the plurality of photoelectric conversion units adjacent to each other in the second direction, the first isolation unit having a first bottom within the semiconductor substrate and the second isolation unit having a second bottom within the semiconductor substrate, the first bottom and the second bottom being formed at different depths within the semiconductor substrate.

14. A photodetector device as described in claim 13, wherein the first isolation portion and the second isolation portion extend from the first surface of the semiconductor substrate toward the second surface, and the first bottom portion and the second bottom portion are respectively provided on the second surface side.

15. A photodetector device as described in claim 13, wherein the first isolation portion and the second isolation portion extend from the second surface of the semiconductor substrate toward the first surface, and the first bottom portion and the second bottom portion are respectively provided on the first surface side.

16. The photodetector device described in claim 13, wherein the first isolation portion extends from the first surface of the semiconductor substrate toward the second surface, the second isolation portion extends from the second surface of the semiconductor substrate toward the first surface, and the first bottom portion is provided on the second surface side, and the second bottom portion is provided on the first surface side.

17. The photodetector device according to claim 13, wherein the first isolation portion and the second isolation portion intersect with each other substantially at the center of the pixel.

18. The photodetector device described in claim 13, wherein one of the first isolation portion and the second isolation portion comprises a pair of protrusions extending from each of a pair of opposing sides of the inter-pixel isolation portion to approximately just before the center of the pixel between the plurality of photoelectric conversion portions adjacent in the first direction or the second direction, and the other of the first isolation portion and the second isolation portion extends between the pair of protrusions and separates the plurality of photoelectric conversion portions adjacent in the second direction or the first direction.

19. The photodetector device described in claim 13, wherein the first isolation portion and the second isolation portion are formed by trenches provided in the semiconductor substrate, and the difference in depth between the first bottom portion and the second bottom portion is formed by an impurity diffusion region.

20. A photodetector comprising: a semiconductor substrate having opposing first and second surfaces, in which a plurality of pixels are arranged in a two-dimensional array, and in which a plurality of photoelectric conversion units are embedded for each pixel, the photoelectric conversion units being adjacent to each other in a first direction and a second direction perpendicular to the first direction; inter-pixel isolation units embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and inter-element isolation units embedded in the semiconductor substrate, the inter-element isolation units including: first isolation units provided between the plurality of photoelectric conversion units adjacent to each other in the first direction and having a first perimeter in a plan view; and second isolation units provided between the plurality of photoelectric conversion units adjacent to each other in the second direction and having a second perimeter in a plan view; wherein when the first direction is a phase difference acquisition direction and the second direction is a direction other than a phase difference acquisition direction, the second perimeter is shorter than the first perimeter.

21. The photodetector device of claim 20, wherein the pixel has a substantially square shape consisting of a pair of sides opposing the first direction and a pair of sides opposing the second direction, the first isolation portion comprises a pair of first protrusions extending from each of the pair of sides opposing the second direction of the inter-pixel isolation portion between the plurality of photoelectric conversion portions adjacent in the first direction to approximately just before the center of the pixel, the second isolation portion comprises a pair of second protrusions extending from each of the pair of sides opposing the first direction of the inter-pixel isolation portion between the plurality of photoelectric conversion portions adjacent in the second direction to approximately just before the center of the pixel, and the longitudinal length of the pair of first protrusions is longer than the longitudinal length of the pair of second protrusions.

22. The photodetector device of claim 20, wherein the pixel has a substantially square shape consisting of a pair of sides opposing the first direction and a pair of sides opposing the second direction, the first isolation portion comprises a pair of first protrusions extending from each of the pair of sides opposing the second direction of the inter-pixel isolation portion between the plurality of photoelectric conversion portions adjacent in the first direction to approximately just before the center of the pixel, the second isolation portion comprises a pair of second protrusions extending from each of the pair of sides opposing the first direction of the inter-pixel isolation portion between the plurality of photoelectric conversion portions adjacent in the second direction to approximately just before the center of the pixel, and the width in the short side of the pair of second protrusions is narrower than the width in the short side of the pair of first protrusions.

23. The photodetector device of claim 20, wherein the pixel has a generally rhombic shape consisting of a pair of vertices opposing each other in the first direction and a pair of vertices opposing each other in the second direction, the first isolation portion comprises a pair of first protrusions extending from each of the pair of vertices opposing each other in the second direction of the inter-pixel isolation portion to approximately just before the center of the pixel between the plurality of photoelectric conversion portions adjacent in the first direction, the second isolation portion comprises a pair of second protrusions extending from each of the pair of vertices opposing each other in the first direction of the inter-pixel isolation portion to approximately just before the center of the pixel between the plurality of photoelectric conversion portions adjacent in the second direction, and the longitudinal length of the pair of first protrusions is longer than the longitudinal length of the pair of second protrusions.

24. The photodetector device of claim 20, wherein the pixel has a generally rhombic shape consisting of a pair of vertices opposing each other in the first direction and a pair of vertices opposing each other in the second direction, the first isolation portion comprises a pair of first protrusions extending from each of the pair of vertices opposing each other in the second direction of the inter-pixel isolation portion to approximately just before the center of the pixel between the plurality of photoelectric conversion portions adjacent in the first direction, the second isolation portion comprises a pair of second protrusions extending from each of the pair of vertices opposing each other in the first direction of the inter-pixel isolation portion to approximately just before the center of the pixel between the plurality of photoelectric conversion portions adjacent in the second direction, and the width in the short side of the pair of second protrusions is narrower than the width in the short side of the pair of first protrusions.

25. The photodetector device according to claim 20, wherein the first isolation portion is a trench provided in the semiconductor substrate and filled with an insulating material, and the second isolation portion is an impurity diffusion region provided in the semiconductor substrate.

26. The photodetector device according to claim 20, further comprising a plurality of third isolation portions extending from the inter-pixel isolation portion toward approximately the center of the pixel in a direction at approximately 45° to the first direction and the second direction.

27. A semiconductor substrate having opposing first and second surfaces, in which a plurality of pixels are arranged in a two-dimensional array, and in which a plurality of photoelectric conversion units adjacent to each other in a first direction and a second direction perpendicular to the first direction are embedded for each pixel; an inter-pixel isolation portion embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and an inter-element isolation portion embedded in the semiconductor substrate, the inter-element isolation portion including: a first isolation portion consisting of a pair of first protrusions extending from each of a pair of sides of the inter-pixel isolation portion opposing each other in the second direction between the plurality of photoelectric conversion units adjacent to each other in the first direction to approximately just before the center of the pixel; and a second isolation portion consisting of a pair of second protrusions extending from each of a pair of sides of the inter-pixel isolation portion opposing each other in the first direction between the plurality of photoelectric conversion units adjacent to each other in the second direction to approximately just before the center of the pixel, wherein the pair of first protrusions each have first side surfaces opposing each other in the semiconductor substrate, the pair of second protrusions each have a second side surface that faces each other in the semiconductor substrate, and the first side surface and the second side surface form angles that are different from each other with respect to the second surface of the semiconductor substrate.

28. A light detection device as described in claim 27, wherein the distance between the pair of first protrusions on the first surface side is narrower than the distance between the pair of first protrusions on the second surface side, and the distance between the pair of second protrusions on the first surface side is narrower than the distance between the pair of second protrusions on the second surface side.

29. A light detection device as described in claim 27, wherein the distance between the pair of first protrusions on the first surface side is wider than the distance between the pair of first protrusions on the second surface side, and the distance between the pair of second protrusions on the first surface side is wider than the distance between the pair of second protrusions on the second surface side.

30. An optical detection device as described in claim 27, wherein the distance between the pair of first protrusions on the first surface side is narrower than the distance between the pair of first protrusions on the second surface side, and the distance between the pair of second protrusions on the first surface side is wider than the distance between the pair of second protrusions on the second surface side.

31. The photodetector device according to claim 27, wherein the first isolation portion and the second isolation portion are formed by a trench provided in the semiconductor substrate and filled with an insulating material, and an impurity diffusion region provided on the side surface of the trench.

32. A photodetector comprising: a semiconductor substrate having opposing first and second surfaces, a plurality of pixels arranged in a two-dimensional array, and a plurality of photoelectric conversion units adjacent in at least a first direction embedded in each of the pixels; an inter-pixel isolation portion embedded in the semiconductor substrate so as to surround each of the plurality of pixels; and an inter-element isolation portion embedded in the semiconductor substrate, including, within each of the pixels, a first isolation portion consisting of a pair of first protrusions extending from each of a pair of opposing sides of the inter-pixel isolation portion in a second direction perpendicular to the first direction toward approximately the center of the pixel between the plurality of photoelectric conversion units adjacent in the first direction, wherein the plurality of pixels include a first pixel and a second pixel having detection wavelengths different from each other, the pair of first protrusions having a first gap therebetween, and the pair of first protrusions provided on the first pixel and the second pixel, respectively, differ from each other in at least one of the formation positions in the first direction within the pixel and the position of the first gap within the pixel.

33. The photodetector device of claim 32, wherein the plurality of pixels further includes a third pixel having a detection wavelength different from that of the first pixel and the second pixel, and the pair of first protrusions provided on the first pixel, the second pixel, and the third pixel, respectively, are different from each other in at least one of the formation positions in the first direction within the pixel and the position of the first gap within the pixel.

34. The photodetector device of claim 33, wherein the first pixel is a red pixel that detects wavelengths in a red band, the second pixel is a green pixel that detects wavelengths in a green band, and the third pixel is a blue pixel that detects wavelengths in a blue band, and the green pixel has the pair of first protrusions formed at positions that divide the pixel approximately evenly in the first direction, and the first gap formed at approximately the center of the pixel, and the red pixel and the blue pixel have the pair of first protrusions formed at positions that divide the pixel unevenly in the first direction, and the first gap formed at a position shifted in a predetermined direction from approximately the center of the pixel.

35. The photodetector according to claim 32, wherein the inter-element isolation portions provided in the first pixel and the second pixel respectively have different thicknesses in the in-plane direction of the semiconductor substrate.

36. The photodetector device according to claim 32, wherein the first pixel and the second pixel have inter-element isolation portions that extend in different directions between the first surface and the second surface of the semiconductor substrate.

37. A photodetector according to claim 32, wherein the pair of first protrusions provided in the first pixel have different protrusion amounts on the first surface side and the second surface side of the semiconductor substrate.

38. The photodetector device of claim 32, wherein the pixel includes the plurality of photoelectric conversion units adjacent in the first direction and the second direction, the inter-element isolation unit further includes a second isolation unit embedded in the semiconductor substrate within the pixel, the second isolation unit comprising a pair of second protrusions extending from each of a pair of sides of the inter-pixel isolation unit opposing each other in the first direction toward approximately the center of the pixel between the plurality of photoelectric conversion units adjacent in the second direction, the pair of second protrusions having a second gap therebetween, and the pair of second protrusions provided in the first pixel and the second pixel, respectively, differ from each other in at least one of their formation positions in the second direction within the pixel and the position of the second gap within the pixel.

39. The photodetector device described in claim 32, wherein the semiconductor substrate further has a pixel array section in which the plurality of pixels are arranged in a two-dimensional array, and at least one of the formation positions in the first direction within the pixels of the pair of first protrusions provided on the first pixel and the second pixel, respectively, and the position of the first gap within the pixels, are different from each other in the peripheral portion of the pixel array section.

40. The light detection device according to claim 32, wherein the first gap substantially coincides with the focusing position of light incident on each of the first pixel and the second pixel.

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