Solid-state imaging device and electronic device

Abstract

To improve the accuracy of phase difference detection while suppressing the deterioration of a photographed image.SOLUTION: A solid state image pickup device includes a pixel array part in which a plurality of pixels including the pixels forming a plurality of photoelectric conversion elements to one on-chip lens are arrayed in the two-dimensional shape. A portion of at least one of an inter-pixel separation part and an inter-pixel light shielding part formed between the pixels protrudes toward the center of the pixels to form a protrusion part. The technique can be applied to a CMOS image sensor having the pixels for phase difference detection.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present technology relates to a solid-state imaging device and an electronic device, and more particularly to a solid-state imaging device and an electronic device that are capable of improving the accuracy of phase difference detection while suppressing degradation of a captured image. [Background technology]

[0002] In recent years, solid-state imaging devices in which image surface phase difference detection pixels are arranged have been used in order to improve the speed of autofocus.

[0003] In this type of solid-state imaging device, a method of partially blocking light using a metal film or the like is commonly adopted in order to divide the light focused by the on-chip lens into pupils. However, the information obtained from the light-blocking pixels cannot be used as information for the captured image, and therefore must be interpolated using information obtained from the surrounding pixels.

[0004] In addition, since the light-shielding pixels cannot be disposed over the entire surface of the effective pixels, the amount of light received by the entire phase difference pixels is reduced, which is a drawback in that the accuracy of phase difference detection is reduced especially when the amount of light is weak.

[0005] One technique to avoid this is to embed multiple photoelectric conversion elements under a single on-chip lens to perform pupil division. This method is adopted, for example, as solid-state imaging devices for single-lens reflex cameras and built-in cameras in smartphones (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-165126 A Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, in a solid-state imaging device having two photoelectric conversion elements directly under a single on-chip lens, the output of one photoelectric conversion element may be mixed with the output of the other photoelectric conversion element, which may result in a decrease in accuracy of phase difference detection.

[0008] One technique to avoid this is to provide a physical separator between the two photoelectric conversion elements. However, particularly when the focus is coincident, this separator can impede photoelectric conversion in the photoelectric conversion elements, reducing sensitivity. In addition, light scattering occurs in the separator, degrading the spectral characteristics, which can result in a deterioration in the image quality of the captured image.

[0009] The present technology has been made in consideration of such circumstances, and is intended to improve the accuracy of phase difference detection while suppressing degradation of a captured image. [Means for solving the problem]

[0010] In the solid-state imaging device according to one aspect of the present technology, No. 1 Photoelectric conversion element and a second photoelectric conversion element a pixel array section in which a plurality of pixels including a pixel formed with the above-mentioned is arranged in a two-dimensional manner, The pixel separation portion a part of the first protrusion and a second protrusion protrude toward a center of the pixel, the inter-pixel isolation portion physically isolates adjacent pixels from each other by a first material embedded in a groove formed in a semiconductor layer in which the first photoelectric conversion element and the second photoelectric conversion element are formed, and the inter-pixel light shielding portion shields adjacent pixels from light by a second material formed in a region between the on-chip lens and the semiconductor layer; The above No. 1 Photoelectric conversion element and the second photoelectric conversion element is formed as a first conductive type region, and the first protrusion and the second protrusion are No. 1 Photoelectric conversion element and the second photoelectric conversion element and the first protrusion and the second protrusion are formed in a second conductive type region between the first protrusion and the second protrusion. and charges stored in the first photoelectric conversion element and the second photoelectric conversion element can be exchanged. It is a solid-state imaging device.

[0011] In the solid-state imaging device according to one aspect of the present technology, No. 1 Photoelectric conversion element and a second photoelectric conversion elementA pixel array section is provided in which a plurality of pixels including a pixel having the above-mentioned structure are arranged in a two-dimensional manner, and an inter-pixel isolation section and an inter-pixel light shielding section are formed between the pixels. The pixel separation portion A part of the first protrusion and the second protrusion are formed by protruding toward the center of the pixel. the inter-pixel isolation portion physically isolates adjacent pixels from each other by a first material embedded in a groove formed in a semiconductor layer in which the first photoelectric conversion element and the second photoelectric conversion element are formed, and the inter-pixel light shielding portion shields adjacent pixels from light by a second material formed in a region between the on-chip lens and the semiconductor layer; The above No. 1 Photoelectric conversion element and the second photoelectric conversion element is formed as a first conductive type region, and the first protrusion and the second protrusion are No. 1 Photoelectric conversion element and the second photoelectric conversion element and the first protrusion and the second protrusion are formed in a second conductive type region between the first protrusion and the second protrusion. and capable of exchanging charges stored in the first photoelectric conversion element and the second photoelectric conversion element. It is a structure.

[0014] According to one aspect of the present technology, an electronic device is No. 1 Photoelectric conversion element and a second photoelectric conversion element a pixel array section in which a plurality of pixels including a pixel having the above-mentioned structure are arranged in a two-dimensional manner, and The pixel separation portion a part of the first protrusion and a second protrusion protrude toward a center of the pixel, the inter-pixel isolation portion physically isolates adjacent pixels from each other by a first material embedded in a groove formed in a semiconductor layer in which the first photoelectric conversion element and the second photoelectric conversion element are formed, and the inter-pixel light shielding portion shields adjacent pixels from light by a second material formed in a region between the on-chip lens and the semiconductor layer; The above No. 1 Photoelectric conversion element and the second photoelectric conversion element is formed as a first conductive type region, and the first protrusion and the second protrusion are No. 1 Photoelectric conversion element and the second photoelectric conversion element and the first protrusion and the second protrusion are formed in a second conductive type region between the first protrusion and the second protrusion. and charges stored in the first photoelectric conversion element and the second photoelectric conversion element can be exchanged. The solid-state imaging device is mounted on an electronic device.

[0015] In a solid-state imaging device mounted on an electronic device according to one aspect of the present technology, No. 1 Photoelectric conversion element and a second photoelectric conversion element A pixel array section is provided in which a plurality of pixels including a pixel having the above-mentioned structure are arranged in a two-dimensional manner, and an inter-pixel isolation section and an inter-pixel light shielding section are formed between the pixels. The pixel separation portion A part of the first protrusion and the second protrusion are formed by protruding toward the center of the pixel. the inter-pixel isolation portion physically isolates adjacent pixels from each other by a first material embedded in a groove formed in a semiconductor layer in which the first photoelectric conversion element and the second photoelectric conversion element are formed, and the inter-pixel light shielding portion shields adjacent pixels from light by a second material formed in a region between the on-chip lens and the semiconductor layer; The above No. 1 Photoelectric conversion element and the second photoelectric conversion element is formed as a first conductive type region, and the first protrusion and the second protrusion are No. 1 Photoelectric conversion element and the second photoelectric conversion element and the first protrusion and the second protrusion are formed in a second conductive type region between the first protrusion and the second protrusion. and capable of exchanging charges stored in the first photoelectric conversion element and the second photoelectric conversion element. It is a structure. Effect of the Invention

[0016] According to one aspect of the present technology, it is possible to improve the accuracy of phase difference detection while suppressing deterioration of a captured image.

[0017] Note that the effects described herein are not necessarily limited to those described herein, and may be any of the effects described in this disclosure. [Brief description of the drawings]

[0018] [Figure 1] 1 is a diagram showing an example of the configuration of an embodiment of a solid-state imaging device to which the present technology is applied; [Diagram 2] FIG. 2 is a cross-sectional view showing the structure of a pixel having two photoelectric conversion elements directly under one on-chip lens. [Diagram 3] FIG. 11 is a diagram showing output results according to the incident angle of light for each photoelectric conversion element. [Figure 4] FIG. 1 is a diagram showing a structure of a pixel having two photoelectric conversion elements directly under one on-chip lens. [Diagram 5] FIG. 13 is a diagram showing a pixel structure for improving the accuracy of phase difference detection. [Figure 6] FIG. 1 is a diagram showing a planar layout of a general pixel. [Figure 7] FIG. 1 is a cross-sectional view showing a structure of a general pixel. [Figure 8] FIG. 1 is a diagram illustrating an N-type potential inside a silicon layer of a typical pixel. [Figure 9] FIG. 2 is a diagram showing a planar layout of a pixel according to the first embodiment. [Figure 10]4A and 4B are diagrams for explaining an N-type potential inside a silicon layer of a pixel according to the first embodiment; [Figure 11] FIG. 2 is a first cross-sectional view showing a structure of a pixel according to the first embodiment. [Figure 12] FIG. 4 is a second cross-sectional view showing the structure of the pixel according to the first embodiment. [Figure 13] FIG. 4 is a third cross-sectional view showing the structure of the pixel according to the first embodiment. [Figure 14] FIG. 2 is a three-dimensional diagram showing the structure of a pixel according to the first embodiment. [Figure 15] FIG. 11 is a three-dimensional diagram showing the structure of a pixel according to the second embodiment. [Figure 16] FIG. 13 is a three-dimensional diagram showing the structure of a pixel according to the third embodiment. [Figure 17] FIG. 13 is a plan view showing a structure of a pixel according to a fourth embodiment. [Figure 18] FIG. 13 is a plan view showing a first modified example of the pixel structure according to the fourth embodiment. [Figure 19] FIG. 13 is a plan view showing a second modified example of the pixel structure according to the fourth embodiment. [Figure 20] FIG. 13 is a plan view showing a third modified example of the pixel structure according to the fourth embodiment. [Figure 21] FIG. 13 is a plan view showing a fourth modified example of the pixel structure according to the fourth embodiment. [Figure 22] FIG. 13 is a plan view showing a structure of a pixel according to a fifth embodiment. [Diagram 23] 11 is a diagram illustrating the relationship between the diameter of the spot of incident light and the length of a protrusion. FIG. [Figure 24] FIG. 13 is a plan view showing a structure of a pixel according to a sixth embodiment. [Diagram 25] FIG. 23 is a plan view showing a pixel structure according to the seventh embodiment. [Figure 26] FIG. 23 is a plan view showing a modified example of the pixel structure according to the seventh embodiment. [Figure 27] FIG. 23 is a plan view showing a pixel structure according to the eighth embodiment. [Figure 28] FIG. 23 is a diagram showing a planar layout of a pixel according to a ninth embodiment. [Figure 29] FIG. 23 is a diagram for explaining an N-type potential inside a silicon layer of a pixel according to the ninth embodiment. [Diagram 30] FIG. 13 is a cross-sectional view showing a structure of a pixel according to a ninth embodiment. [Diagram 31] FIG. 23 is a cross-sectional view showing a first example of a pixel structure according to a tenth embodiment. [Diagram 32] FIG. 23 is a cross-sectional view showing a second example of the pixel structure according to the tenth embodiment. [Diagram 33] FIG. 23 is a cross-sectional view showing a third example of a pixel structure according to the tenth embodiment. [Diagram 34] FIG. 23 is a cross-sectional view showing a fourth example of a pixel structure according to the tenth embodiment. [Diagram 35] FIG. 23 is a cross-sectional view showing a fifth example of a pixel structure according to the tenth embodiment. [Diagram 36] FIG. 23 is a cross-sectional view showing a sixth example of a pixel structure according to the tenth embodiment. [Figure 37] FIG. 23 is a cross-sectional view showing a seventh example of a pixel structure according to the tenth embodiment. [Figure 38] FIG. 23 is a cross-sectional view showing an eighth example of a pixel structure according to the tenth embodiment. [Figure 39] FIG. 23 is a cross-sectional view showing a ninth example of a pixel structure according to the tenth embodiment. [Diagram 40] FIG. 16 is a cross-sectional view showing a tenth example of a pixel structure according to the tenth embodiment. [Diagram 41] FIG. 23 is a cross-sectional view showing an eleventh example of the pixel structure according to the tenth embodiment. [Diagram 42] FIG. 23 is a diagram showing a schematic diagram of a potential distribution of a pixel according to a tenth embodiment. [Diagram 43] FIG. 23 is a cross-sectional view showing a first example of a pixel structure according to an eleventh embodiment. [Diagram 44] FIG. 23 is a cross-sectional view showing a second example of the pixel structure according to the eleventh embodiment. [Diagram 45] FIG. 23 is a cross-sectional view showing a third example of a pixel structure according to the eleventh embodiment. [Figure 46]FIG. 23 is a plan view showing a fourth example of a pixel structure according to the eleventh embodiment. [Figure 47] FIG. 23 is a plan view showing a fifth example of a pixel structure according to the eleventh embodiment. [Figure 48] FIG. 23 is a cross-sectional view showing a sixth example of a pixel structure according to the eleventh embodiment. [Figure 49] FIG. 26 is a cross-sectional view showing a first example of a pixel structure according to a twelfth embodiment. [Figure 50] FIG. 11 is a diagram showing output results according to the incident angle of light for each photoelectric conversion element. [Figure 51] FIG. 23 is a cross-sectional view showing a second example of the pixel structure according to the twelfth embodiment. [Figure 52] FIG. 23 is a cross-sectional view showing a third example of a pixel structure according to the twelfth embodiment. [Figure 53] FIG. 23 is a cross-sectional view showing a fourth example of a pixel structure according to the twelfth embodiment. [Figure 54] FIG. 23 is a cross-sectional view showing a fifth example of a pixel structure according to the twelfth embodiment. [Figure 55] FIG. 23 is a plan view showing a sixth example of a pixel structure according to the twelfth embodiment. [Figure 56] FIG. 23 is a plan view showing a seventh example of a pixel structure according to the twelfth embodiment. [Figure 57] 23A and 23B are diagrams illustrating an example of a planar layout and a cross section of a pixel according to a thirteenth embodiment; [Figure 58] FIG. 1 is a cross-sectional view showing a structure of a general pixel. [Figure 59] FIG. 23 is a cross-sectional view showing a first example of a pixel structure according to a thirteenth embodiment. [Figure 60] FIG. 23 is a cross-sectional view showing a second example of the pixel structure according to the thirteenth embodiment. [Figure 61] FIG. 23 is a cross-sectional view showing a third example of a pixel structure according to the thirteenth embodiment. [Figure 62] FIG. 2 is a diagram showing a circuit configuration of a pixel according to each embodiment. [Figure 63] 1 is a block diagram showing an example of the configuration of an electronic device including a solid-state imaging device to which the present technology is applied. [Figure 64]1A to 1C are diagrams illustrating examples of use of a solid-state imaging device to which the present technology is applied. [Figure 65] 1 is a diagram showing an outline of a configuration example of a stacked solid-state imaging device to which the technology according to the present disclosure can be applied; [Figure 66] 1 is a cross-sectional view showing a first configuration example of a stacked solid-state imaging device. [Figure 67] FIG. 11 is a cross-sectional view showing a second configuration example of a stacked solid-state imaging device. [Figure 68] FIG. 11 is a cross-sectional view showing a third configuration example of a stacked solid-state imaging device. [Figure 69] 11 is a cross-sectional view showing another configuration example of a stacked solid-state imaging device to which the technology according to the present disclosure can be applied. [Figure 70] 1 is a block diagram showing an example of a schematic configuration of a vehicle control system; [Figure 71] 4 is an explanatory diagram showing an example of the installation positions of an outside-vehicle information detection unit and an imaging unit; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present technology will be described with reference to the drawings. The description will be given in the following order.

[0020] 1. Structure of solid-state imaging device 2. Prerequisite Technology 3. Embodiments of the present technology (1) First embodiment: Structure with protrusions in inter-pixel Si isolation (basic structure) (2) Second embodiment: Structure with protrusions for inter-pixel light shielding (3) Third embodiment: Structure with inter-pixel silicon isolation and protrusions for inter-pixel light shielding (4) Fourth embodiment: Structure in which protrusions are formed for each R, G, and B pixel (5) Fifth embodiment: Structure with adjusted length of protrusion (6) Sixth embodiment: Structure in which the length of the protrusion is adjusted for each pixel (7) Seventh embodiment: Structure using elliptical on-chip lens (8) Eighth embodiment: Structure in which multiple pixels are arranged on a single on-chip lens (9) Ninth embodiment: Structure physically separated from the surface opposite the light incident side (10) Tenth embodiment: Structure in which the amount of fixed charge is different between the central part of the PD and the other parts (11) Eleventh embodiment: A structure in which the central portion of the PD of the same color is a low refractive area and the central portion of the PD of a different color is a metal area. (12) Twelfth embodiment: Structure in which OCL is made of multiple materials with different refractive indices (13) Thirteenth embodiment: A structure in which a vertical transistor is formed in the center of a PD of the same color 4. Pixel circuit configuration 5. Variations 6. Configuration of Electronic Devices 7. Examples of use of solid-state imaging devices 8. Configuration example of stacked solid-state imaging device to which the technology disclosed herein can be applied 9. Application examples for mobile objects

[0021] <1. Configuration of solid-state imaging device>

[0022] (Example of the configuration of a solid-state imaging device) FIG. 1 is a diagram showing an example of the configuration of an embodiment of a solid-state imaging device to which the present technology is applied.

[0023] The CMOS image sensor 10 in Fig. 1 is an example of a solid-state imaging device using a CMOS (Complementary Metal Oxide Semiconductor). The CMOS image sensor 10 captures incident light (image light) from a subject via an optical lens system (not shown), converts the amount of incident light focused on an imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs the electrical signal as a pixel signal.

[0024] In FIG. 1, a CMOS image sensor 10 includes a pixel array section 11, a vertical drive circuit 12, a column signal processing circuit 13, a horizontal drive circuit 14, an output circuit 15, a control circuit 16, and an input / output terminal 17.

[0025] A plurality of pixels 100 are arranged two-dimensionally (in a matrix) in the pixel array section 11. Each pixel 100 includes a photodiode (PD) as a photoelectric conversion element and a plurality of pixel transistors. For example, the pixel transistor includes a transfer transistor, a reset transistor, an amplification transistor, and a selection transistor.

[0026] In the following description, in addition to the pixel 100, the pixel 200, pixel 300, pixel 400, and pixel 500 will also be described as pixels arranged in the pixel array unit 11.

[0027] The vertical drive circuit 12 is configured with, for example, a shift register, selects a predetermined pixel drive line 21, and supplies a pulse for driving the pixels 100 to the selected pixel drive line 21, thereby driving the pixels 100 row by row. That is, the vertical drive circuit 12 sequentially selects and scans each pixel 100 of the pixel array unit 11 row by row in the vertical direction, and supplies a pixel signal based on a signal charge (electric charge) generated in the photoelectric conversion element of each pixel 100 according to the amount of received light to the column signal processing circuit 13 through the vertical signal line 22.

[0028] The column signal processing circuit 13 is arranged for each column of the pixels 100, and performs signal processing such as noise removal for each pixel column on signals output from one row of the pixels 100. For example, the column signal processing circuit 13 performs signal processing such as correlated double sampling (CDS) for removing fixed pattern noise specific to each pixel and AD (Analog-Digital) conversion.

[0029] The horizontal drive circuit 14 is configured, for example, by a shift register, and sequentially outputs horizontal scanning pulses to select each of the column signal processing circuits 13 in turn, and cause each of the column signal processing circuits 13 to output a pixel signal to the horizontal signal line 23.

[0030] The output circuit 15 processes and outputs the signals sequentially supplied from each of the column signal processing circuits 13 through the horizontal signal line 23. Note that the output circuit 15 may perform only buffering, or may perform black level adjustment, column variation correction, various digital signal processing, and the like.

[0031] The control circuit 16 controls the operation of each part of the CMOS image sensor 10 .

[0032] Furthermore, the control circuit 16 generates clock signals and control signals that serve as a reference for the operations of the vertical drive circuit 12, the column signal processing circuit 13, the horizontal drive circuit 14, etc., based on the vertical synchronization signal, the horizontal synchronization signal, and the master clock signal. The control circuit 16 outputs the generated clock signals and control signals to the vertical drive circuit 12, the column signal processing circuit 13, the horizontal drive circuit 14, etc.

[0033] The input / output terminal 17 exchanges signals with the outside.

[0034] The CMOS image sensor 10 in Fig. 1 configured as above is a CMOS image sensor called a column AD type in which a column signal processing circuit 13 that performs CDS processing and AD conversion processing is arranged for each pixel column. Also, the CMOS image sensor 10 in Fig. 1 can be, for example, a back-illuminated CMOS image sensor.

[0035] <2. Prerequisite Technology>

[0036] (Pixel structure) 2 is a cross-sectional view showing the structure of a pixel 700 having two photoelectric conversion elements 713A and 713B directly below one on-chip lens 711. In addition to the on-chip lens 711 and the photoelectric conversion elements 713A and 713B, the pixel 700 is configured to include a color filter 712, an inter-pixel light shielding portion 714, an inter-pixel isolation portion 715, and transfer gates 151A and 151B.

[0037] 2, the pixel 700 has a structure in which two photoelectric conversion elements, a photoelectric conversion element 713A and a photoelectric conversion element 713B, are provided for one on-chip lens 711. In the following description, such a structure is also referred to as a 2PD structure.

[0038] In the pixel 700, incident light IL collected by the on-chip lens 711 passes through a color filter 712 and is irradiated onto a photoelectric conversion region of the photoelectric conversion element 713A or the photoelectric conversion element 713B.

[0039] 2, incident light IL is intensively irradiated onto the photoelectric conversion region of photoelectric conversion element 713A according to the incident angle θi. Ideally, then, if the output of photoelectric conversion element 713A is 100, the output of photoelectric conversion element 713B should be 0, but in reality, a certain amount of output is also produced from photoelectric conversion element 713B.

[0040] Fig. 3 shows output results according to the incident angle θi of light for each photoelectric conversion element 713. In Fig. 3, the output of photoelectric conversion element 713A is represented by a solid curve A, and the output of photoelectric conversion element 713B is represented by a dotted curve B.

[0041] 3, the output values ​​of curve A corresponding to the output of photoelectric conversion element 713A and curve B corresponding to the output of photoelectric conversion element 713B match when the incident angle θi is 0 degrees, that is, when light is incident from directly above. That is, curve A and curve B have a line-symmetric relationship with the output when the incident angle θi = 0 as the axis of symmetry.

[0042] Due to this relationship, for example, when incident light IL is intensively irradiated onto the photoelectric conversion region of photoelectric conversion element 713A as shown in Fig. 2, if not only the output of photoelectric conversion element 713A but also the output of photoelectric conversion element 713B increases, the accuracy of phase difference detection will decrease. For example, in Fig. 3, when attention is paid to the incident angle θa, not only the output from photoelectric conversion element 713A but also the output from photoelectric conversion element 713B is produced.

[0043] That is, the photoelectric conversion element 713A and the photoelectric conversion element 713B are used as a pair to detect the phase difference, but if the output of one photoelectric conversion element 713 (713A or 713B) is mixed with the output of the other photoelectric conversion element 713 (713B or 713A), this will lead to a decrease in detection accuracy.

[0044] Here, as a structure for preventing the output of one photoelectric conversion element 713 from being mixed with the output of the other photoelectric conversion element 713, a structure is envisaged in which a physical separator is formed between photoelectric conversion element 713A and photoelectric conversion element 713B formed in a silicon (Si) layer.

[0045] Specifically, Figure 4 shows a pixel 700 having a 2PD structure corresponding to Figure 2, and as shown in the plan view and the X-X' cross-sectional view, an inter-pixel light-shielding portion 714 and an inter-pixel separation portion 715 are formed, but no physical separation portion is formed between photoelectric conversion element 713A and photoelectric conversion element 713B.

[0046] In contrast, Fig. 5 shows a pixel 800 in which a physical separator is provided between photoelectric conversion elements. In the pixel 800 in Fig. 5, an inter-element separator 816 is formed in a silicon layer between photoelectric conversion elements 813A and 813B, and the photoelectric conversion elements 813A and 813B are physically separated from each other.

[0047] In this way, in a pixel 800 having a 2PD structure, by forming an inter-element separation portion 816, the output of one photoelectric conversion element 813 (813A or 813B) is prevented from being mixed with the output of the other photoelectric conversion element 813 (813B or 813A), thereby improving the accuracy of phase difference detection.

[0048] However, when the inter-element isolation portion 816 is formed in the pixel 800 shown in Fig. 5, the inter-element isolation portion 816 may impede photoelectric conversion in the photoelectric conversion region of the photoelectric conversion element 813A or the photoelectric conversion element 813B, particularly when the focus is matched, and may result in a decrease in sensitivity. Also, it has been confirmed that light scattering ("SL" in Fig. 5) occurs in the inter-element isolation portion 816, deteriorating the spectral characteristics and causing a decrease in the image quality of the captured image.

[0049] 3. Embodiments of the present technology

[0050] Next, the structure of a pixel 100 to which the present technology is applied will be described. For comparison, the structure of a general pixel 900 will be described with reference to Figures 6 to 8, and then the structure of a pixel 100 to which the present technology is applied will be described with reference to Figures 9 to 62.

[0051] (General pixel structure) First, the structure of a general pixel 900 will be described with reference to Fig. 6 to Fig. 8. Fig. 6 is a diagram showing a planar layout of a general pixel 900. The pixel 900 includes an on-chip lens 911, a color filter 912, photoelectric conversion elements 913A and 913B, an inter-pixel light shielding portion 914, an inter-pixel isolation portion 915, and transfer gates 951A and 951B.

[0052] 6, of the multiple pixels 900 arranged two-dimensionally (in a matrix) in the pixel array section, 4 rows and 4 columns of pixels 900 arranged in a partial region are shown as a representative example. In addition, in FIG. 6, the i-th row and j-th column of the pixels 900 arranged in the pixel array section is represented as pixel 900-ij.

[0053] In this pixel array section, a plurality of pixels 900 are arranged two-dimensionally in a Bayer array. Here, the Bayer array is an array pattern in which green (G) pixels are arranged in a checkerboard pattern, and red (R) pixels and blue (B) pixels are arranged alternately in rows in the remaining portion.

[0054] In the following description, an R color filter that transmits red (R) wavelength components is provided as a color filter, and a pixel that obtains an electric charge corresponding to R component light from light that has passed through the R color filter is referred to as an R pixel. A pixel that obtains an electric charge corresponding to G component light from light that has passed through a G color filter that transmits green (G) wavelength components is referred to as a G pixel. A pixel that obtains an electric charge corresponding to B component light from light that has passed through a B color filter that transmits blue (B) wavelength components is referred to as a B pixel.

[0055] In the pixel array section, each pixel 900 is a square unit pixel having a 2PD structure, and is physically separated in a silicon layer by inter-pixel isolation sections 915 arranged in a square lattice (square lattice). Although not shown in Fig. 6, in this pixel array section, inter-pixel light shielding sections 914 are arranged in a square lattice, similar to the inter-pixel isolation sections 915.

[0056] In addition, since each pixel 900 has a 2PD structure, a photoelectric conversion region of a photoelectric conversion element 913A and a photoelectric conversion region of a photoelectric conversion element 913B are formed in a silicon layer. These photoelectric conversion regions are separated by impurities in the silicon layer, as shown by dotted lines in the column direction in the figure.

[0057] Here, the X-X' cross section in the plan view shown in Fig. 6 can be expressed as a cross section as shown in Fig. 7. However, here, it is assumed that the upper left pixel 900 in the 4-row, 4-column pixel array shown in Fig. 6 is pixel 900-11. Therefore, the pixels 900 that are the subject of the X-X' cross section are G pixel 900-41, B pixel 900-42, G pixel 900-43, and B pixel 900-44.

[0058] 7, the G pixel 900-41 has a 2PD structure having a photoelectric conversion element 913A and a photoelectric conversion element 913B. In the photoelectric conversion element 913A, a charge corresponding to the G component light is generated from the light that is collected by the on-chip lens 911 and transmitted through the G color filter 912. In addition, in the photoelectric conversion element 913B, a charge corresponding to the G component light is generated in the same manner as in the photoelectric conversion element 913A.

[0059] In the G pixel 900-43, similar to the G pixel 900-41, a charge corresponding to the G component is generated by the photoelectric conversion element 913A and the photoelectric conversion element 913B. In the B pixels 900-42 and 900-44, a charge corresponding to the B component is generated by the photoelectric conversion element 913A and the photoelectric conversion element 913B.

[0060] In this manner, in each pixel 900, the charges generated by the photoelectric conversion element 913A and the photoelectric conversion element 913B are read out via the transfer gate 951A and the transfer gate 951B and used as information for phase difference detection.

[0061] 8 is a plan view of the light incident surface (light incident surface) of pixel 900, and shows the N-type potential inside the silicon layer. That is, in pixel 900 physically separated by inter-pixel separation portion 915 formed in a square lattice shape, the photoelectric conversion region of photoelectric conversion element 913A and the photoelectric conversion region of photoelectric conversion element 913B are formed as N-type regions, and the region excluding these photoelectric conversion regions is formed as a P-type region.

[0062] In the pixel 900 having such a structure, since electric charges are not accumulated in the P-type region excluding the photoelectric conversion region, it is not clear whether the electric charges generated in the P-type region should move to the photoelectric conversion region side of the photoelectric conversion element 913A or the photoelectric conversion element 913B. In addition, in the N-type photoelectric conversion region, when the cross section is taken into consideration, the concentration increases toward the transfer gate 951 side, and the concentration is low on the light incident surface side. Therefore, in the photoelectric conversion region, it is difficult to draw in the electric charges generated on the light incident surface side where the N-type concentration is low.

[0063] That is, in Figure 8, since the contribution of isolation between the photoelectric conversion elements in the P-type regions A1 and A2 is low, it is desirable to isolate photoelectric conversion element 913A from photoelectric conversion element 913B. However, as described above, simply providing a physical isolation portion (inter-element isolation portion 816 in Figure 5) between photoelectric conversion element 913A and photoelectric conversion element 913B results in a degradation in image quality of the captured image.

[0064] Therefore, in the technology disclosed herein (the present technology), a protrusion protruding from the inter-pixel separation portion or the inter-pixel light shielding portion is provided in the P-type regions A1 and A2, and the destination of the electric charge generated in the P-type region is separated, thereby making it possible to improve the accuracy of phase difference detection while suppressing deterioration of the captured image.

[0065] The specific contents of the present technology will be described below with reference to the first to thirteenth embodiments. First, the first to ninth embodiments will describe structures having protrusions, and then the tenth to thirteenth embodiments will describe other structures.

[0066] (1) First embodiment

[0067] (Plane layout of pixels) FIG. 9 is a diagram showing a planar layout of the pixel 100 according to the first embodiment.

[0068] 9, a 4-row, 4-column array of pixels 100 arranged in a partial region is illustrated as a representative example of the multiple pixels 100 arranged two-dimensionally in the pixel array section 11. In the pixel array section 11, the multiple pixels 100 are arranged two-dimensionally in a Bayer array.

[0069] 9, the pixel 100 in the i-th row and j-th column arranged in the pixel array unit 11 is represented as pixel 100-ij. This representation is also used in other embodiments described later.

[0070] In the pixel array section 11, each pixel 100 is a square unit pixel having a 2PD structure, and is physically separated in a silicon layer (semiconductor layer) by inter-pixel separation sections 115 arranged in a square lattice pattern.

[0071] However, among the pixels 100 arranged in the pixel array section 11, in the G pixel 100, a part of the inter-pixel separation section 115 is formed so as to protrude in a protruding manner toward the center of the G pixel 100. In the following description, this protruding part is referred to as a protruding portion 115P.

[0072] For example, in the 4 row, 4 column pixel arrangement in the pixel array section 11 shown in Figure 9, if the upper left pixel 100 is pixel 100-11, then G pixel 100-12, G pixel 100-14, G pixel 100-21, G pixel 100-23, G pixel 100-32, G pixel 100-34, G pixel 100-41, and G pixel 100-43 are the G pixels 100 on which the protrusion 115P is to be formed.

[0073] That is, in these G pixels 100, a part of the inter-pixel isolation portion 115 protrudes in a protruding manner toward the center of the G pixel 100 to form a protruding portion 115P. Here, as shown in Fig. 10, the region in which the protruding portion 115P is formed corresponds to the P-type regions A1 and A2 in Fig. 8 described above, which are considered to have a low contribution to isolation between photoelectric conversion elements.

[0074] By forming protrusions 115P protruding from the inter-pixel separation portion 115 in two regions corresponding to the P-type regions A1 and A2, the destination of the charges generated in the P-type regions is separated, thereby improving the accuracy of phase difference detection while suppressing a decrease in sensitivity and an increase in color mixing.

[0075] Furthermore, since the G pixel 100 has a 2PD structure, a photoelectric conversion region of the photoelectric conversion element 113A and a photoelectric conversion region of the photoelectric conversion element 113B are formed in the silicon layer. These photoelectric conversion regions are separated by impurities in the silicon layer, as shown by the dotted lines in the column direction in Fig. 9. In other words, no physical separation section (inter-element separation section 816 in Fig. 5) is formed in the center of the G pixel 100 responsible for pupil division, and the photoelectric conversion regions are separated by the impurity distribution inside the silicon layer.

[0076] Here, the X1-X1' cross section in the plan view shown in Fig. 9 can be represented as a cross section as shown in Fig. 11. However, even here, if the upper left pixel 100 in the 4-row, 4-column pixel array is pixel 100-11, the X1-X1' cross section covers four pixels: G pixel 100-41, B pixel 100-42, G pixel 100-43, and B pixel 100-44.

[0077] 11, the G pixel 100-41 has a 2PD structure having a photoelectric conversion element 113A and a photoelectric conversion element 113B. In the photoelectric conversion element 113A, a charge corresponding to the G component light is generated from the light that is collected by the on-chip lens 111 and transmitted through the G color filter 112. Similarly to the photoelectric conversion element 113A, the photoelectric conversion element 113B generates a charge corresponding to the G component light.

[0078] In the G pixel 100-43, similar to the G pixel 100-41, a charge corresponding to the G component is generated by the photoelectric conversion element 113A and the photoelectric conversion element 113B. In the B pixels 100-42 and 100-44, a charge corresponding to the B component is generated by the photoelectric conversion element 113A and the photoelectric conversion element 113B.

[0079] In this manner, in each pixel 100, the charges generated by the photoelectric conversion element 113A and the photoelectric conversion element 113B are read out via the transfer gate 151A and the transfer gate 151B and used as information for phase difference detection.

[0080] The pixels 100-41 to 100-44 are square unit pixels having a 2PD structure, and adjacent pixels are shielded from light by inter-pixel light shielding portions 114 arranged in a square lattice pattern. The inter-pixel light shielding portions 114 are formed of a material such as a metal containing tungsten (W) or aluminum (Al), and are arranged in a region between the on-chip lens 111 and the silicon layer in which the photoelectric conversion region is formed.

[0081] In addition, the pixels 100-41 to 100-44 are physically separated from adjacent pixels in the silicon layer by inter-pixel isolation sections 115 arranged in a square lattice pattern. That is, for example, by using DTI (Deep Trench Isolation) technology, the inter-pixel isolation sections 115 are formed by filling a material such as an oxide film or a metal into a groove section (trench) that is dug in a square lattice pattern according to the shape of a square unit pixel from a light incident side surface (light incident surface) in a silicon layer in which a photoelectric conversion region is formed.

[0082] Here, in the G pixel 100-41 and the G pixel 100-43, a protrusion 115P is formed between the photoelectric conversion element 113A and the photoelectric conversion element 113B. That is, in the G pixel 100-41 and the G pixel 100-43 shown in FIG. 11, a part of the inter-pixel separation portion 115 protrudes in a protruding shape toward the center of the G pixel 100, thereby forming the protrusion 115P.

[0083] Furthermore, the X2-X2' cross section in the plan view shown in Fig. 9 can be expressed as a cross section as shown in Fig. 12. However, in Fig. 12, similarly to Fig. 11, G pixel 100-41, B pixel 100-42, G pixel 100-43, and B pixel 100-44 are the subjects of the X2-X2' cross section.

[0084] Here, the X2-X2' cross section is a cross section including the center of the G pixel 100, and does not include the protrusion 115P that protrudes in a protruding manner toward the center. That is, in the G pixels 100-41 and 100-43 shown in FIG. 12, the protrusion 115P is not formed between the photoelectric conversion element 113A and the photoelectric conversion element 113B.

[0085] Furthermore, the Y-Y' cross section in the plan view shown in Fig. 9 can be expressed as a cross section as shown in Fig. 13. However, even here, if the upper left pixel 100 in the 4-row, 4-column pixel array is pixel 100-11, the pixels that are the subject of the Y-Y' cross section are G pixel 100-12, B pixel 100-22, G pixel 100-32, and B pixel 100-42.

[0086] 13, in the G pixel 100-12 and the G pixel 100-32, a part of the inter-pixel separation portion 115 protrudes in a protruding manner toward the center of the G pixel 100, forming a protruding portion 115P. However, in the protruding portion 115P shown in FIG. 13, the depth of each protruding portion is different (the depth is not uniform).

[0087] That is, when viewed in the plan view shown in Figure 9, the protrusion 115P can be seen to be formed in a T-shape with respect to the inter-pixel separation portion 115, but as shown in Figure 13, the base portion of the protrusion 115P has the same depth as the inter-pixel separation portion 115, and the depth gradually becomes shallower toward the tip side of the protrusion 115P.

[0088] As described above, in the G pixel 100, a part of the inter-pixel separation portion 115 protrudes in a protruding manner toward the center of the G pixel 100, forming a protrusion 115P. However, as shown in Figures 11 to 13, the presence or absence of the protrusion 115P and its shape (depth) vary depending on the cross-sectional cut.

[0089] In other words, when the protrusion 115P of the inter-pixel separation portion 115 is formed in a pixel 100 having a 2PD structure, in a first cross-section (e.g., the cross-section of Figure 11) that does not include the center of the pixel 100, the cross-section of the protrusion 115P is included between the two photoelectric conversion regions, but in a second cross-section (e.g., the cross-section of Figure 12) that includes the center of the pixel 100, the cross-section of the protrusion 115P is not included between the two photoelectric conversion regions.

[0090] (Pixel structure of the first embodiment) FIG. 14 is a three-dimensional diagram showing the spatial structure of the pixel 100 according to the first embodiment.

[0091] 14 illustrates an arbitrary pixel 100 (for example, a G pixel 100 having a protrusion 115P) among a plurality of pixels 100 arranged two-dimensionally in the pixel array section 11. In the pixel array section 11, inter-pixel light shielding sections 114 and inter-pixel isolation sections 115 are formed in a square lattice pattern between adjacent pixels.

[0092] The inter-pixel light shielding portions 114 are formed in a square lattice pattern from metals such as tungsten (W) or aluminum (Al) to provide light shielding between adjacent pixels. The inter-pixel isolation portions 115 are formed from oxide films, metals, or the like embedded in square lattice grooves (trenches) dug into the silicon layer to physically isolate adjacent pixels.

[0093] In the first embodiment, for a pixel 100 which is a square unit having a 2PD structure, among the inter-pixel light shielding portions 114 and inter-pixel isolation portions 115 which are formed in a square lattice pattern, a portion of the inter-pixel isolation portion 115 protrudes in a protruding manner toward the center of the pixel 100 to form a protrusion portion 115P.

[0094] The material of the protrusion 115P may be the same as or different from that of the inter-pixel isolation portion 115. For example, when the inter-pixel isolation portion 115 is made of an oxide film, the protrusion 115P may also be made of an oxide film. Furthermore, when the inter-pixel isolation portion 115 is made of a metal, the protrusion 115P may also be made of an oxide film.

[0095] In this manner, in pixel 100, protrusions 115P formed in two locations on inter-pixel separation portion 115 are formed in regions within the silicon layer that contribute little to isolation. By forming protrusions 115P in such regions, it is possible to improve the accuracy of phase difference detection while suppressing a decrease in sensitivity and an increase in color mixing.

[0096] The details will be described later with reference to Figures 22 and 23, but in order to prevent physical separation (silicon separation) by the protrusion 115P directly below the on-chip lens 111, for example, the length of the protruding portion of the protrusion 115P can be determined depending on the diameter of the focused spot by the on-chip lens 111.

[0097] The first embodiment has been described above.

[0098] (2) Second embodiment

[0099] (Pixel structure of the second embodiment) FIG. 15 is a three-dimensional diagram showing the spatial structure of the pixel 100 according to the second embodiment.

[0100] 15, similarly to the above-described Fig. 14, an arbitrary pixel 100 is shown among a plurality of pixels 100 arranged two-dimensionally in the pixel array section 11. In the pixel array section 11, inter-pixel light shielding sections 114 and inter-pixel isolation sections 115 are formed in a square lattice pattern between adjacent pixels.

[0101] In the second embodiment, for a pixel 100 which is a square unit having a 2PD structure, inter-pixel light-shielding portions 114 and inter-pixel isolation portions 115 which are formed in a square lattice pattern, a portion of the inter-pixel light-shielding portion 114 protrudes in a protruding manner toward the center of the pixel 100 to form a protrusion 114P.

[0102] The material of the protrusion 114P may be the same as that of the inter-pixel light shielding portion 114, or may be a different material.

[0103] In this manner, in the above-described first embodiment, a protrusion 115P is formed on the inter-pixel isolation portion 115, but in the second embodiment, a protrusion 114P is formed on the inter-pixel light shielding portion 114.

[0104] That is, in pixel 100, protrusions 114P formed in two locations on inter-pixel light shielding portion 114 are formed in regions within the silicon layer that contribute little to separation, and by forming protrusions 114P in such regions, it is possible to improve the accuracy of phase difference detection while suppressing a decrease in sensitivity and an increase in color mixing.

[0105] Details will be described later with reference to FIGS. 22 and 23, but for example, the length of the protruding portion of the protrusion 114P can be determined according to the diameter of the light spot focused by the on-chip lens 111.

[0106] The second embodiment has been described above.

[0107] (3) Third embodiment

[0108] (Pixel structure of the third embodiment) FIG. 16 is a three-dimensional diagram showing the spatial structure of the pixel 100 according to the third embodiment.

[0109] 16, similarly to the above-described Fig. 14 and Fig. 15, an arbitrary pixel 100 is shown among a plurality of pixels 100 arranged two-dimensionally in the pixel array section 11. In the pixel array section 11, inter-pixel light shielding sections 114 and inter-pixel isolation sections 115 are formed in a square lattice pattern between adjacent pixels.

[0110] In the third embodiment, for a pixel 100 which is a square unit consisting of a 2PD structure, a portion of both the inter-pixel light-shielding portion 114 and the inter-pixel separation portion 115 which are formed in a square lattice pattern protrude in a protruding manner toward the center of the pixel 100, thereby forming a protrusion portion 114P and a protrusion portion 115P.

[0111] The material of the protrusion 114P may be the same as or a different material from that of the inter-pixel light shielding portion 114. The material of the protrusion 115P may be the same as or a different material from that of the inter-pixel isolation portion 115.

[0112] In this manner, in the above-described first embodiment, a case was described in which protrusion portion 115P was formed on inter-pixel isolation portion 115, and in the above-described second embodiment, a case was described in which protrusion portion 114P was formed on inter-pixel light shielding portion 114, whereas in the third embodiment, protrusion portion 114P and protrusion portion 115P are formed on both inter-pixel light shielding portion 114 and inter-pixel isolation portion 115, respectively.

[0113] That is, in the pixel 100, the protrusions 114P formed in two places on the inter-pixel light shielding portion 114 are formed in a region in the silicon layer that contributes less to separation. Also, in the pixel 100, the protrusions 115P formed in two places on the inter-pixel isolation portion 115 are formed in a region in the silicon layer that contributes less to separation. By forming the protrusions 114P and 115P in such a region, it is possible to improve the accuracy of phase difference detection while suppressing a decrease in sensitivity and an increase in color mixing.

[0114] The details will be described later with reference to Figures 22 and 23, but for example, the length of the protruding portions of the protrusions 114P and 115P can be determined depending on the diameter of the focused spot by the on-chip lens 111.

[0115] The third embodiment has been described above.

[0116] (4) Fourth embodiment

[0117] (Protrusions are formed only on the G pixels) FIG. 17 is a plan view showing the structure of a pixel 100 according to the fourth embodiment.

[0118] In Figure 17, of the multiple pixels 100 arranged two-dimensionally in the pixel array section 11, a 4-row, 4-column array of pixels 100 arranged in a partial region is shown as a representative example, and of the pixels 100 arranged in the Bayer array, only the G pixels 100 have a protrusion 115P formed with respect to the inter-pixel separation section 115.

[0119] For example, in the 4 row by 4 column pixel array shown in Figure 17, if the upper left pixel 100 is pixel 100-11, then G pixel 100-12, G pixel 100-14, G pixel 100-21, G pixel 100-23, G pixel 100-32, G pixel 100-34, G pixel 100-41, and G pixel 100-43 are considered to be the G pixels 100 for which protrusion 115P is formed.

[0120] Here, when comparing the information obtained from the output of the G pixel 100 with the information obtained from the output of the R pixel 100 and the B pixel 100, if the information obtained from the output of the G pixel 100 is the greatest, and for example, when obtaining information for phase difference detection, the information obtained from the output of the G pixel 100 is dominant, then a configuration can be adopted in which the protrusion 115P is formed only on the G pixel 100, as shown in Figure 17.

[0121] Note that the structure in which the protrusion 115P is formed on the inter-pixel isolation portion 115 only in the G pixel 100 shown in Fig. 17 is similar to the structure shown in Fig. 9. Also, as shown by the dotted line in the column direction in the figure for the pixel 100, the photoelectric conversion region of the photoelectric conversion element 113A and the photoelectric conversion region of the photoelectric conversion element 113B are separated by impurities in the silicon layer.

[0122] 17 illustrates a case in which the protrusion 115P is formed on the inter-pixel isolation portion 115 in accordance with the first embodiment described above, but in accordance with the second embodiment described above, the protrusion 114P may be formed on the inter-pixel light shielding portion 114 only in the G pixel 100. Furthermore, in accordance with the third embodiment described above, protrusions may be formed on both the inter-pixel light shielding portion 114 and the inter-pixel isolation portion 115 only in the G pixel 100.

[0123] (A structure in which protrusions are formed on all pixels) FIG. 18 is a plan view showing a first modified example of the structure of the pixel 100 according to the fourth embodiment.

[0124] Figure 18 shows an example of an arbitrary set of four rows and four columns of pixels 100 among the multiple pixels 100 arranged in a Bayer array in the pixel array section 11, and in all of the pixels 100, a protrusion portion 115P is formed on the inter-pixel separation portion 115.

[0125] For example, in the 4-row, 4-column pixel array shown in FIG. 18, if the upper left pixel 100 is pixel 100-11, then the R pixels 100 (100-11, 100-13, 100-31, 100-33), the G pixels 100 (100-12, 100-14, 100-21, 100-23, 100-32, 100-34, 100-41, 100-43), and the B pixels 100 (100-22, 100-24, 100-42, 100-44) are the pixels 100 for which the protrusion 115P is formed.

[0126] Here, when protrusions 115P are formed in the R pixel 100, the G pixel 100, and the B pixel 100, phase difference detection information can be obtained from the output of all the pixels 100. Therefore, for example, when it is desired to obtain phase difference detection information from all the pixels 100, a configuration can be adopted in which protrusions 115P are formed for all the pixels 100, as shown in FIG. 18.

[0127] 18 has been described in relation to the case where the protrusion 115P is formed on the inter-pixel isolation portion 115 in accordance with the above-described first embodiment, but in accordance with the above-described second embodiment, the protrusion 114P may be formed on the inter-pixel light shielding portion 114 in all pixels 100. Furthermore, in accordance with the above-described third embodiment, the protrusions may be formed on both the inter-pixel light shielding portion 114 and the inter-pixel isolation portion 115 in all pixels 100.

[0128] (Protrusions are formed only on the R pixels) FIG. 19 is a plan view showing a second modified example of the structure of the pixel 100 according to the fourth embodiment.

[0129] Figure 19 shows an example of an arbitrary set of 4 rows and 4 columns of pixels 100 among the multiple pixels 100 arranged in a Bayer array in the pixel array section 11, and a protrusion portion 115P is formed on the inter-pixel separation portion 115 only in the R pixel 100.

[0130] For example, in the 4-row, 4-column pixel array shown in Figure 19, if the upper left pixel 100 is pixel 100-11, R pixel 100-11, R pixel 100-13, R pixel 100-31, and R pixel 100-33 are the R pixels 100 for which protrusion 115P is formed.

[0131] 19, a case has been described in which the protrusion 115P is formed on the inter-pixel isolation portion 115 in accordance with the above-described first embodiment, but in accordance with the above-described second embodiment, the protrusion 114P may be formed on the inter-pixel light shielding portion 114 only in the R pixel 100. Furthermore, in accordance with the above-described third embodiment, protrusions may be formed on both the inter-pixel light shielding portion 114 and the inter-pixel isolation portion 115 only in the R pixel 100.

[0132] (Structure with protrusions formed only on B pixels) FIG. 20 is a plan view showing a third modified example of the structure of the pixel 100 according to the fourth embodiment.

[0133] In Figure 20, of the multiple pixels 100 arranged in a Bayer array in the pixel array section 11, an arbitrary set of 4 rows and 4 columns of pixels 100 is shown as an example, and a protrusion portion 115P is formed on the inter-pixel separation portion 115 only in the B pixel 100.

[0134] For example, in the 4-row, 4-column pixel array shown in Figure 20, if the upper left pixel 100 is pixel 100-11, then B pixel 100-22, B pixel 100-24, B pixel 100-42, and B pixel 100-44 are the B pixels 100 for which protrusion 115P is formed.

[0135] 20 illustrates a case where the protrusion 115P is formed on the inter-pixel isolation portion 115 in accordance with the first embodiment described above, but in accordance with the second embodiment described above, the protrusion 114P may be formed on the inter-pixel light shielding portion 114 only in the B pixel 100. Furthermore, in accordance with the third embodiment described above, protrusions may be formed on both the inter-pixel light shielding portion 114 and the inter-pixel isolation portion 115 only in the B pixel 100.

[0136] (Structure with protrusions formed only on G and B pixels) FIG. 21 is a plan view showing a fourth modified example of the structure of the pixel 100 according to the fourth embodiment.

[0137] In Figure 21, an example of any 4 rows and 4 columns of pixels 100 among the multiple pixels 100 arranged in a Bayer array in the pixel array section 11 is shown, and a protrusion portion 115P is formed on the inter-pixel separation portion 115 only in the G pixel 100 and the B pixel 100.

[0138] For example, in the 4-row, 4-column pixel array shown in Figure 21, if the upper left pixel 100 is pixel 100-11, then the G pixels 100 (100-12, 100-14, 100-21, 100-23, 100-32, 100-34, 100-41, 100-43) and the B pixels 100 (100-22, 100-24, 100-42, 100-44) are the pixels 100 for which the protrusion 115P is formed.

[0139] 21 illustrates a case where the protrusion 115P is formed on the inter-pixel isolation portion 115 in accordance with the first embodiment described above, but in accordance with the second embodiment described above, the protrusion 114P may be formed on the inter-pixel light shielding portion 114 only on the G pixel 100 and the B pixel 100. Furthermore, in accordance with the third embodiment described above, the protrusions may be formed on both the inter-pixel light shielding portion 114 and the inter-pixel isolation portion 115 only on the G pixel 100 and the B pixel 100.

[0140] Further, although a combination of a G pixel 100 and a B pixel 100 has been exemplified here as a combination of pixels 100 forming a protrusion 115P, the combination pattern of pixels 100 forming the protrusion 115P is arbitrary, for example, a combination of an R pixel 100 and a G pixel 100, or a combination of an R pixel 100 and a B pixel 100.

[0141] The fourth embodiment has been described above.

[0142] (5) Fifth embodiment

[0143] (Determination of the length of the protrusion) FIG. 22 is a plan view showing the structure of a pixel 100 according to the fifth embodiment.

[0144] 22, in pixel 100, a part of inter-pixel separator 115 arranged in a square lattice pattern protrudes toward the center of pixel 100 to form protrusion 115P. The length of the protruding part of protrusion 115P (hereinafter also referred to as protrusion length) may be any length, but can be determined, for example, as follows.

[0145] That is, for example, when changing the height of the on-chip lens 111 in the optical axis direction (stacking direction), if the diameter of the focused spot S on the light incident surface of the silicon (Si) layer on which the photoelectric conversion elements 113A, 113B are formed becomes large for some reason, it is necessary to shorten the protruding length of the protrusion 115P in order to avoid scattering of light.

[0146] In this way, since the protrusion length of the protrusion 115P correlates with the diameter of the focused spot S of the on-chip lens 111, the protrusion length of the protrusion 115P can be determined according to the diameter of the focused spot S of the on-chip lens 111.

[0147] For example, the inventor of the present technology conducted detailed simulations and found that when the protrusion length of the protrusion portion 115P is L1 and the length of one side of the pitch of the on-chip lens 111 is L2, it is preferable for L1 to be approximately 1 / 7 to 1 / 4 of L2.

[0148] 23 shows a structure in which the position of the on-chip lens 111 is higher than the light incident surface of the silicon layer in the cross-sectional view of A in Fig. 23, and a structure in which the position of the on-chip lens 111 is lower in the cross-sectional view of B in Fig. 23. The cross-sectional view of Fig. 23 corresponds to the Y-Y' cross section in the plan view shown in Fig. 9.

[0149] In FIG. 23A, the height of the on-chip lens 111 in the optical axis direction with respect to the light incident surface of the silicon layer is H A The incident light IL A The focal spot on the light incident surface by AOn the other hand, in B of FIG. 23, the height of the on-chip lens 111 in the optical axis direction with respect to the light incident surface of the silicon layer is represented by H B The incident light IL B The focal spot on the light incident surface by B It is expressed as:

[0150] Comparing the height of the on-chip lens 111 in FIG. 23A and FIG. 23B, H A > H B Since the height of the on-chip lens 111 has such a relationship, when the diameter of the focused spot is compared between FIG. 23A and FIG. 23B, S A < S B This results in the following relationship.

[0151] Based on this relationship, in A of FIG. 23, the focused spot S A The protruding length L1 of the protruding portion 115P depends on the diameter of the A is adjusted, and in FIG. 23B, the focused spot S B The protruding length L1 of the protruding portion 115P depends on the diameter of the B However, as mentioned above, the larger the diameter of the focused spot, the shorter the projection length must be to avoid scattering of light. A < S B Depending on the relationship between L1 A > L1 B This results in the following relationship.

[0152] Note that, although a method for determining the protruding length of the protrusion 115P of the inter-pixel separation portion 115 in accordance with the diameter of the focused spot S of the on-chip lens 111 has been described here, the length (protruding length) of the protruding portion of the protrusion 114P of the inter-pixel light shielding portion 114 can also be determined in a similar manner in accordance with the diameter of the focused spot S of the on-chip lens 111.

[0153] Furthermore, the above-mentioned method of determining the protrusion length of the protrusion 115P is just one example, and the protrusion length of the protrusion 115P may be determined by a method other than the method using the diameter of the focused spot S of the on-chip lens 111.

[0154] The fifth embodiment has been described above.

[0155] (6) Sixth embodiment

[0156] (The length of the protrusions varies for each pixel.) FIG. 24 is a plan view showing the structure of a pixel 100 according to the sixth embodiment.

[0157] Figure 24 shows an example of an arbitrary set of four rows and four columns of pixels 100 among the multiple pixels 100 arranged in a Bayer array in the pixel array section 11, and in all of the pixels 100, a protrusion portion 115P is formed on the inter-pixel separation portion 115.

[0158] For example, in the 4-row, 4-column pixel array shown in FIG. 24, if the upper left pixel 100 is pixel 100-11, then the R pixels 100 (100-11, 100-13, 100-31, 100-33), the G pixels 100 (100-12, 100-14, 100-21, 100-23, 100-32, 100-34, 100-41, 100-43), and the B pixels 100 (100-22, 100-24, 100-42, 100-44) are the pixels 100 for which the protrusion 115P is formed.

[0159] 24, the protrusion length of the protrusion 115P differs for each of the color pixels, the R pixel 100, the G pixel 100, and the B pixel 100. That is, in FIG. 24, compared to the protrusion length of the protrusion 115P formed in the G pixel 100, the protrusion length of the protrusion 115P formed in the R pixel 100 is shorter, whereas the protrusion length of the protrusion 115P formed in the B pixel 100 is longer.

[0160] That is, the protrusion length of the protrusion 115P of the R pixel 100 is set to L1 R The protruding length of the protruding portion 115P of the G pixel 100 is L1 G The protruding length of the protruding portion 115P of the B pixel 100 is L1 B Then, L1 B> L1 G > L1 R This results in the following relationship.

[0161] For example, since the wavelength of red (R) is longer than the wavelengths of green (G) and blue (B), there is a higher probability of light scattering occurring in the R pixel 100 compared to the G pixel 100 and the B pixel 100. Therefore, it is conceivable to take measures such as making the protrusion length of the protrusion portion 115P of the R pixel 100 shorter than the protrusion length of the G pixel 100 and the B pixel 100.

[0162] Note that, although the case where the protrusion length of the protrusion portion 115P of the inter-pixel separation portion 115 is changed for each pixel 100 has been described here, the length (protrusion length) of the protruding portion of the protrusion portion 114P of the inter-pixel light shielding portion 114 may also be changed for each pixel 100 in a similar manner.

[0163] In the above description, the protrusion length of the protrusion 115P is changed for all of the R, G and B pixels 100, but any combination of pixels 100 for which the protrusion length of the protrusion 115P is changed may be used, for example, the protrusion lengths of the protrusions 115P of the G and B pixels 100 may be the same, and only the protrusion length of the protrusion 115P of the R pixel 100 may be shortened. Furthermore, the protrusion length of the protrusion 115P may be changed not only for pixels 100 of different colors, but also for pixels 100 of the same color.

[0164] The sixth embodiment has been described above.

[0165] (7) Seventh embodiment

[0166] (Structure using elliptical on-chip lenses in the row direction) FIG. 25 is a plan view showing the structure of a pixel 100 according to the seventh embodiment.

[0167] 25 illustrates an example of an arbitrary set of 4 rows and 4 columns of pixels 100 among a plurality of pixels 100 arranged two-dimensionally in the pixel array section 11. However, in the 4 rows and 4 columns pixel array shown in FIG. 25, each pixel 100 has a structure including one photoelectric conversion element 113. That is, in FIG. 25, each pixel 100 has a so-called 1PD structure, not a 2PD structure. Here, in order to distinguish it from the pixel 100 having the above-mentioned 2PD structure, the pixel 100 having the 1PD structure will be referred to as pixel 100 (1PD).

[0168] 25, if the upper left pixel 100(1PD) is pixel 100-11(1PD), an elliptical on-chip lens 111E is formed for G pixels 100-21(1PD) and 100-22(1PD) arranged in the same row. Although not shown, one photoelectric conversion element 113 is formed for each on-chip lens 111 in the other pixels 100(1PD) except for the G pixels 100-21(1PD) and 100-22(1PD).

[0169] That is, in a pixel composed of two pixels (G pixels 100-21(1PD) and 100-22(1PD)) arranged in the same row, the photoelectric conversion element 113 of the G pixel 100-21(1PD) and the photoelectric conversion element 113 of the G pixel 100-22(1PD) are provided for one on-chip lens 111E. Here, phase difference detection is performed by using the outputs of the photoelectric conversion element 113 of the G pixel 100-21(1PD) and the photoelectric conversion element 113 of the G pixel 100-22(1PD) arranged in the same row.

[0170] Also, here, when the elliptical on-chip lens 111E has a structure spanning the G pixels 100-21 (1PD) and 100-22 (1PD) in the row direction, the protrusion 115P formed in the inter-pixel separation portion 115 is formed between the G pixels 100-21 (1PD) and 100-22 (1PD).

[0171] Even in this case, a part of the inter-pixel separation portion 115 protrudes in a protruding shape toward the center of the area consisting of the G pixel 100-21 (1PD) and the G pixel 100-22 (1PD), thereby forming protrusions 115P in two places. Furthermore, the protruding length of the protrusions 115P can be determined according to, for example, the diameter of the light-focus spot of the elliptical on-chip lens 111E.

[0172] (Structure using elliptical on-chip lenses in the column direction) FIG. 26 is a plan view showing a modified example of the structure of the pixel 100 according to the seventh embodiment.

[0173] Fig. 26 illustrates an arbitrary arrangement of 4 rows and 4 columns of pixels 100 among a plurality of pixels 100 arranged two-dimensionally in the pixel array section 11. However, the pixels 100 in the 4 rows and 4 columns pixel arrangement shown in Fig. 26 have a 1PD structure, similar to the pixels 100 shown in Fig. 25 described above, and the pixels 100 having this 1PD structure will be referred to as pixels 100 (1PD).

[0174] 26, for example, an elliptical on-chip lens 111E is formed for the G pixel 100-12 (1PD) and the G pixel 100-22 (1PD) arranged in the same column. Although not shown, one photoelectric conversion element 113 is formed for each on-chip lens 111 in the other pixels 100 (1PD) except for the G pixel 100-12 (1PD) and the G pixel 100-22 (1PD).

[0175] That is, in a pixel composed of two pixels (G pixels 100-12(1PD) and 100-22(1PD)) arranged in the same column, the photoelectric conversion element 113 of the G pixel 100-12(1PD) and the photoelectric conversion element 113 of the G pixel 100-22(1PD) are provided for one on-chip lens 111E. Here, phase difference detection is performed by using the outputs of the photoelectric conversion element 113 of the G pixel 100-12(1PD) and the photoelectric conversion element 113 of the G pixel 100-22(1PD) arranged in the same column.

[0176] Also, here, when the elliptical on-chip lens 111E has a structure spanning the G pixel 100-12 (1PD) and the G pixel 100-22 (1PD) in the column direction, the protrusion 115P formed in the inter-pixel separation portion 115 is formed between the G pixel 100-12 (1PD) and the G pixel 100-22 (1PD).

[0177] Even in this case, a part of the inter-pixel isolation portion 115 protrudes in a protruding shape toward the center of the region consisting of the G pixel 100-12 (1PD) and the G pixel 100-22 (1PD), thereby forming protrusions 115P in two places. Furthermore, the protruding length of the protrusions 115P can be determined according to, for example, the diameter of the light-focus spot of the elliptical on-chip lens 111E.

[0178] Note that, here, the case has been described in which the protrusion portion 115P of the inter-pixel separation portion 115 is formed for two pixels 100 (1PD) in the same row or two pixels 100 (1PD) in the same column arranged for each elliptical on-chip lens 111E, but the protrusion portion 114P of the inter-pixel light shielding portion 114 may be formed.

[0179] In the above description, two G pixels 100 (1PD) are arranged relative to the elliptical on-chip lens 111E. However, the arrangement is not limited to the G pixel 100 (1PD), and an R pixel 100 (1PD) or a B pixel 100 (1PD) may be arranged relative to the elliptical on-chip lens 111E.

[0180] The seventh embodiment has been described above.

[0181] (8) Eighth embodiment

[0182] (A structure in which multiple pixels are arranged on a single on-chip lens) FIG. 27 is a plan view showing the structure of a pixel 100 according to the eighth embodiment.

[0183] Fig. 27 illustrates an arbitrary arrangement of 4 rows and 4 columns of pixels 100 among a plurality of pixels 100 arranged two-dimensionally in the pixel array section 11. However, the pixels 100 in the 4 rows and 4 columns pixel arrangement shown in Fig. 27 have a 1PD structure, similar to the pixels 100 shown in Fig. 25 and Fig. 26 described above, and the pixels 100 having this 1PD structure will be referred to as pixels 100 (1PD).

[0184] In the pixel array of 4 rows and 4 columns shown in FIG. 27, a circular on-chip lens 111 is formed for every four pixels 100 (1PD) of the same color.

[0185] For example, in the 4-row, 4-column pixel array shown in FIG. 27, if the upper left pixel 100(1PD) is pixel 100-11(1PD), then one on-chip lens 111-11 is formed for (a pixel consisting of) four R pixels 100(1PD) consisting of R pixel 100-11(1PD), R pixel 100-12(1PD), R pixel 100-21(1PD), and R pixel 100-22(1PD).

[0186] Furthermore, in the case where the circular on-chip lens 111-11 has a structure spanning four R pixels 100(1PD) (100-11(1PD), 100-12(1PD), 100-21(1PD), 100-22(1PD)), a part of the inter-pixel separation portion 115 protrudes in a protruding manner toward the center of the area consisting of the four R pixels 100(1PD), so that protrusions 115P are formed in four places.

[0187] 27, one on-chip lens 111-12 is formed for (a pixel consisting of) four G pixels 100(1PD) consisting of G pixels 100-13(1PD), G pixels 100-14(1PD), G pixels 100-23(1PD), and G pixels 100-24(1PD). In addition, when the circular on-chip lens 111-12 has a structure spanning the four G pixels 100(1PD) (100-13(1PD), 100-14(1PD), 100-23(1PD), 100-24(1PD)), a part of the inter-pixel separation portion 115 protrudes in a protruding shape toward the center of the area consisting of the four G pixels 100(1PD), so that protrusions 115P are formed in four places.

[0188] 27, one on-chip lens 111-21 is formed for (a pixel consisting of) four G pixels 100(1PD) consisting of G pixels 100-31(1PD), G pixels 100-32(1PD), G pixels 100-41(1PD), and G pixels 100-42(1PD). In the case where the circular on-chip lens 111-21 has a structure spanning the four G pixels 100(1PD) (100-31(1PD), 100-32(1PD), 100-41(1PD), 100-42(1PD)), a part of the inter-pixel separation portion 115 protrudes in a protruding shape toward the center of the area consisting of the four G pixels 100(1PD), so that protrusions 115P are formed in four places.

[0189] 27, one on-chip lens 111-22 is formed for (a pixel composed of) four B pixels 100(1PD) consisting of B pixels 100-33(1PD), B pixels 100-34(1PD), B pixels 100-43(1PD), and B pixels 100-44(1PD). In the case where the circular on-chip lens 111-22 has a structure spanning the four B pixels 100(1PD) (100-33(1PD), 100-34(1PD), 100-43(1PD), 100-44(1PD)), a part of the inter-pixel isolation portion 115 protrudes in a protruding shape toward the center of the region consisting of the four G pixels 100(1PD), so that protrusions 115P are formed in four places.

[0190] 27, a pixel (a pixel composed of four pixels 100 (1PD)) provided with one on-chip lens 111 and one color filter 112 is provided with photoelectric conversion elements 113 of four pixels 100 (1PD). In this case, phase difference detection is performed by using the outputs of the photoelectric conversion elements 113 of the four pixels 100 (1PD) sharing one on-chip lens 111 and one color filter 112. In this case, since two rows and two columns of pixels 100 (1PD) are arranged for one on-chip lens 111, it is possible to obtain information on phase difference detection in both the row direction and the column direction, for example.

[0191] Note that, although the case has been described here in which the protrusion 115P of the inter-pixel isolation portion 115 is formed for two rows and two columns of pixels 100 (1PD) arranged for each on-chip lens 111, the protrusion 114P of the inter-pixel light shielding portion 114 may also be formed.

[0192] The eighth embodiment has been described above.

[0193] (9) Ninth embodiment

[0194] (Plane layout of pixels) FIG. 28 is a diagram showing a planar layout of the pixel 100 according to the ninth embodiment.

[0195] 28 illustrates an example of arbitrary 4-row, 4-column pixels 100 among the multiple pixels 100 arranged in a Bayer array in the pixel array unit 11. However, the pixels 100 in the 4-row, 4-column pixel array shown in Fig. 28 have a 2PD structure, similar to the pixels 100 shown in Fig. 9 and the like described above.

[0196] 28, as in the above-mentioned Fig. 9 etc., in the pixels 100 in the pixel array of 4 rows and 4 columns, in the G pixel 100, a part of the inter-pixel isolation portion 115 protrudes in a protruding manner toward the center of the G pixel 100, forming a protrusion 115P. More specifically, as shown in Fig. 29, the protrusion 115P of the inter-pixel isolation portion 115 is formed in an area corresponding to the P-type areas A1 and A2 which are considered to contribute less to the isolation between the photoelectric conversion elements in the above-mentioned Fig. 8.

[0197] Here, the X-X' cross section in the plan view shown in Fig. 28 can be represented as a cross section as shown in Fig. 30. However, in this case, if the upper left pixel 100 in a 4-row, 4-column pixel array is pixel 100-11, the X-X' cross section covers four pixels: G pixel 100-41, B pixel 100-42, G pixel 100-43, and B pixel 100-44.

[0198] The cross-sectional view of FIG. 30 has a structure basically similar to that of the cross-sectional view of FIG. 11 described above, but the method of processing the inter-pixel isolation portion 115 (manufacturing process) is different.

[0199] 11 described above, a groove (trench) is dug into the silicon layer from the surface on the light incident side (light incident surface) using the DTI technology, and a substance such as an oxide film or a metal is filled into the groove, thereby forming the inter-pixel isolation section 115. On the other hand, in Fig. 30, a groove (trench) is dug into the silicon layer from the surface on the opposite side to the light incident side (the surface on the transfer gates 151A and 151B side), and a substance such as an oxide film or a metal is filled into the groove, thereby forming the inter-pixel isolation section 115.

[0200] The ninth embodiment has been described above.

[0201] (10) Tenth embodiment

[0202] Incidentally, in a solid-state imaging device such as a CMOS image sensor, when inter-element isolation between two photoelectric conversion elements directly below a single on-chip lens is realized by injecting impurities by an implantation method (hereinafter referred to as impurity implantation), the following problem is expected to occur: That is, charges (negative charges, i.e., electrons (carriers)) generated near the silicon interface of the light incident surface (e.g., the back side) where it is difficult to apply an electric field by impurity implantation, or at a location where the electric field of the inter-element isolation section is weak, are not accumulated in the desired left and right photoelectric conversion elements, resulting in a decrease in the accuracy of phase difference detection.

[0203] Therefore, in the tenth embodiment, a structure is adopted for the pixels 200 arranged two-dimensionally in the pixel array section 11 of the CMOS image sensor 10 (FIG. 1), in which the amount of fixed charge at the silicon interface between the center part of the left and right photoelectric conversion elements and the other parts is changed to form a potential gradient from the center part to the left and right photoelectric conversion elements. By adopting such a structure, charges (electrons) photoelectrically converted near the silicon interface can be accumulated in the desired left and right photoelectric conversion elements, thereby improving the detection accuracy of the phase difference.

[0204] The pixel structure of the tenth embodiment will be described below with reference to FIGS.

[0205] (First example of structure) FIG. 31 is a cross-sectional view showing a first example of a pixel structure according to the tenth embodiment.

[0206] 31, the pixel 200 has a 2PD structure, and includes an on-chip lens 211, a color filter 212, photoelectric conversion elements 213A and 213B, an inter-pixel light shielding portion 214, and an inter-pixel isolation portion 215.

[0207] In the pixel 200, the on-chip lens 211 to the inter-pixel isolation portion 215 correspond to the on-chip lens 111, the color filter 112, the photoelectric conversion elements 113A and 113B, the inter-pixel light shielding portion 114, and the inter-pixel isolation portion 115 constituting the pixel 100 (FIG. 11, etc.) of the above-described embodiment, respectively, and therefore the description thereof will be omitted here as appropriate. However, in the pixel 200 in FIG. 31, the inter-pixel isolation portion 215 is formed of an oxide film.

[0208] In the pixel 200, incident light IL collected by the on-chip lens 211 passes through the color filter 212 and is irradiated onto the photoelectric conversion region of the photoelectric conversion element 213A or the photoelectric conversion element 213B.

[0209] A in FIG. 31 shows the incident light IL A 31B shows a case where the focused light spot of the incident light IL is shifted to the left from the center of the left and right photoelectric conversion elements 213A and 213B, that is, a case where there is a phase difference shift. B 13 shows a case where the focused spot is located at the center between the left and right photoelectric conversion elements 213A and 213B, that is, where there is no deviation in phase difference.

[0210] Here, in the silicon layer (semiconductor layer), the amount of fixed charge at the silicon interface on the light incident side differs between the central parts of the left and right photoelectric conversion elements 213A, 213B and the other parts.

[0211] Specifically, when comparing the amount of fixed charge in central region 221 (first region), which is the central region, at the silicon interface on the light incident side, with the amount of fixed charge in left and right regions 222 (second regions), which are the regions excluding the central region (regions to the left and right of the central region), the amount of fixed charge in central region 221 is greater than the amount of fixed charge in left and right regions 222.

[0212] In this way, by changing the amount of fixed charge between the central region 221 and the left and right regions 222 at the silicon interface on the light incident side and forming a potential gradient from the center between the left and right photoelectric conversion elements 213A, 213B to the left and right photoelectric conversion elements 213A, 213B, electrons photoelectrically converted at the silicon interface can be accumulated in the desired left and right photoelectric conversion elements 213A, 213B.

[0213] For example, in the pixel 200 of A in FIG. 31, the incident light IL A When there is a phase difference shift as shown in FIG. 1, electrons photoelectrically converted near the silicon interface are accumulated in the desired left and right photoelectric conversion elements 213A, 213B due to the potential gradient, and the separation ratio is improved, thereby improving the detection accuracy of the phase difference.

[0214] (Second example of structure) FIG. 32 is a cross-sectional view showing a second example of the pixel structure according to the tenth embodiment.

[0215] Fig. 32 shows an enlarged view of a region including a central region 221 and left and right regions 222 at the silicon interface on the light incident side in the cross section of pixel 200 shown in Fig. 31. As shown in this enlarged view, in insulating layer 230 formed on (interface layer 220 of) silicon layer 210, a layer made of High-k film 232A and High-k film 232B is laminated on oxide film 231 and oxide film 233.

[0216] High-k films are made of silicon dioxide (SiO 2 It is a high dielectric constant insulating film (high dielectric constant film) made of a material having a higher relative dielectric constant than insulating films such as SiO 2 .

[0217] Here, in the insulating layer 230, the High-k film 232A is formed on the oxide film 231 so as to correspond to the left and right regions 222 in the interface layer 220. Also, in the insulating layer 230, the High-k film 232B is formed on the oxide film 231 so as to correspond to the central region 221 in the interface layer 220. In the insulating layer 230, an oxide film 233 is formed above the layer consisting of the High-k film 232A and the High-k film 232B.

[0218] The high-k film 232A and the high-k film 232B are different high-dielectric constant films, and are, for example, aluminum oxide (Al 2 O 3 ) and hafnium oxide (HfO 2 The oxide film 231 and the oxide film 233 may be, for example, silicon dioxide (SiO 2 ) can be used.

[0219] Thus, in the pixel 200 of FIG. 32, the insulating layer 230 has a structure in which a High-k film 232B is formed in a portion corresponding to a central region 221 having a large amount of fixed charge in the central portion of the left and right photoelectric conversion elements 213A, 213B, and a High-k film 232A is formed in a portion corresponding to left and right regions 222 having a small amount of fixed charge excluding the central portion.

[0220] By having such a structure, in the pixel 200 of Figure 32, when there is a phase difference shift as shown by the incident light IL in the figure, electrons photoelectrically converted near the silicon interface are accumulated in the desired left and right photoelectric conversion elements 213A, 213B, thereby improving the detection accuracy of the phase difference.

[0221] (Third example of structure) FIG. 33 is a cross-sectional view showing a third example of the pixel structure according to the tenth embodiment.

[0222] FIG. 33, like FIG. 32 described above, shows an enlarged view of a region in the cross section of pixel 200 shown in FIG. 31 that includes central region 221 and left and right regions 222 of the silicon interface, but the cross-sectional structure of insulating layer 230 is different from that in the enlarged view of FIG. 32 described above.

[0223] That is, in insulating layer 230 of FIG. 33, the layer formed between oxide film 231 and oxide film 233 has a structure in which a lower layer consisting of only High-k film 232A and an upper layer consisting of High-k film 232A and High-k film 232B are laminated, and High-k film 232B is embedded in the concave portion of High-k film 232A, which has a concave shape.

[0224] Thus, in the pixel 200 of Figure 33, the insulating layer 230 has a structure in which High-k films 232A, 232B (A+B) are formed in portions corresponding to the central region 221, where the amount of fixed charge is large, of the left and right photoelectric conversion elements 213A, 213B, and High-k films 232A (A) are formed in portions corresponding to the left and right regions 222, excluding the central portions, where the amount of fixed charge is small.

[0225] In other words, at least one of the High-k film in the portion corresponding to the central region 221 and the High-k film in the portions corresponding to the left and right regions 222 can be said to be a laminate of two or more different high dielectric constant films.

[0226] By having such a structure, in the pixel 200 of Figure 33, when there is a phase difference shift as shown by the incident light IL in the figure, electrons photoelectrically converted near the silicon interface are accumulated in the desired left and right photoelectric conversion elements 213A, 213B, thereby improving the detection accuracy of the phase difference.

[0227] (Fourth example of structure) FIG. 34 is a cross-sectional view showing a fourth example of the pixel structure according to the tenth embodiment.

[0228] Figure 34, like Figure 32 described above, shows an enlarged view of a region in the cross section of pixel 200 shown in Figure 31 that includes central region 221 and left and right regions 222 of the silicon interface, but the cross-sectional structure of insulating layer 230 is different from the enlarged view of Figure 32 described above.

[0229] 34, the layer formed between the oxide film 231 and the oxide film 233 has a structure in which a lower layer made of only the High-k film 232A and an upper layer made of the High-k film 232B and the High-k film 232C are laminated together. Here, the High-k film 232C is a high dielectric constant film different from the High-k films 232A and 232B.

[0230] Thus, in the pixel 200 of Figure 34, the insulating layer 230 has a structure in which High-k films 232A, 232C (A+C) are formed in a portion corresponding to the central region 221, where the amount of fixed charge is large, of the left and right photoelectric conversion elements 213A, 213B, and High-k films 232A, 232B (A+B) are formed in portions corresponding to the left and right regions 222, excluding the central portions, where the amount of fixed charge is small.

[0231] In other words, at least one of the High-k film in the portion corresponding to the central region 221 and the High-k film in the portions corresponding to the left and right regions 222 can be said to be a laminate of two or more different high dielectric constant films.

[0232] By having such a structure, in the pixel 200 of Figure 34, when there is a phase difference shift as shown by the incident light IL in the figure, electrons photoelectrically converted near the silicon interface are accumulated in the desired left and right photoelectric conversion elements 213A, 213B, thereby improving the detection accuracy of the phase difference.

[0233] (Fifth example of structure) FIG. 35 is a cross-sectional view showing a fifth example of the pixel structure according to the tenth embodiment.

[0234] Figure 35, like Figure 32 described above, shows an enlarged view of a region in the cross section of pixel 200 shown in Figure 31, including central region 221 and left and right regions 222 of the silicon interface, but the cross-sectional structure of insulating layer 230 is different from the enlarged view of Figure 32 described above.

[0235] That is, in the insulating layer 230 of FIG. 35, the layer formed between the oxide film 231 and the oxide film 233 has a laminated structure including a first layer consisting only of the High-k film 232A, a second layer consisting of the High-k film 232B and the High-k film 232C, and a third layer partially including the High-k film 232D.

[0236] Here, the High-k film 232D is a high dielectric constant film different from the High-k films 232A to 232C. In addition, in the insulating layer 230, the portion of the third layer excluding the High-k film 232D is formed including a part of the oxide film 233 which is the layer thereover.

[0237] Thus, in the pixel 200 of Figure 35, the insulating layer 230 has a structure in which High-k films 232A, 232C, 232D (A+C+D) are formed in a portion corresponding to the central region 221 where the amount of fixed charge is large in the center of the left and right photoelectric conversion elements 213A, 213B, and High-k films 232A, 232B (A+B) are formed in portions corresponding to the left and right regions 222 where the amount of fixed charge is small excluding the central portion.

[0238] In other words, at least one of the High-k film in the portion corresponding to the central region 221 and the High-k film in the portions corresponding to the left and right regions 222 is formed by stacking two or more different high dielectric constant films. It can also be said that the High-k film in the portion corresponding to the central region 221 has a greater number of stacked High-k films than the High-k film in the portions corresponding to the left and right regions 222.

[0239] By having such a structure, in the pixel 200 of Figure 35, when there is a phase difference shift as shown by the incident light IL in the figure, electrons photoelectrically converted near the silicon interface are accumulated in the desired left and right photoelectric conversion elements 213A, 213B, thereby improving the detection accuracy of the phase difference.

[0240] (Sixth example of structure) FIG. 36 is a cross-sectional view showing a sixth example of the pixel structure according to the tenth embodiment.

[0241] Figure 36, like Figure 32 described above, shows an enlarged view of a region in the cross section of pixel 200 shown in Figure 31 that includes central region 221 and left and right regions 222 of the silicon interface, but the cross-sectional structure of insulating layer 230 is different from the enlarged view of Figure 32 described above.

[0242] 36, the layer formed between the oxide film 231 and the oxide film 233 has a laminated structure including a first layer made of only the High-k film 232A, a second layer made of the High-k film 232B and the High-k film 232C, and a third layer made of the High-k film 232D and the High-k film 232E. Here, the High-k film 232E is a high dielectric constant film different from the High-k films 232A to 232D.

[0243] Thus, in the pixel 200 of Figure 36, the insulating layer 230 has a structure in which High-k films 232A, 232C, 232D (A+C+D) are formed in a portion corresponding to the central region 221 where the amount of fixed charge is large in the center of the left and right photoelectric conversion elements 213A, 213B, and High-k films 232A, 232B, 232E (A+B+E) are formed in portions corresponding to the left and right regions 222 where the amount of fixed charge is small excluding the central portion.

[0244] In other words, at least one of the High-k film in the portion corresponding to the central region 221 and the High-k film in the portions corresponding to the left and right regions 222 can be said to be made up of two or more different high dielectric constant films stacked together. It can also be said that the High-k film in the portion corresponding to the central region 221 and the High-k film in the portions corresponding to the left and right regions 222 have the same number of stacked layers.

[0245] By having such a structure, in the pixel 200 of Figure 36, when there is a phase difference shift as shown by the incident light IL in the figure, electrons photoelectrically converted near the silicon interface are accumulated in the desired left and right photoelectric conversion elements 213A, 213B, thereby improving the detection accuracy of the phase difference.

[0246] (Seventh example of structure) FIG. 37 is a cross-sectional view showing a seventh example of the pixel structure according to the tenth embodiment.

[0247] Figure 37, like Figure 32 described above, shows an enlarged view of a region in the cross section of pixel 200 shown in Figure 31 that includes central region 221 and left and right regions 222 of the silicon interface, but the cross-sectional structure of insulating layer 230 is different from the enlarged view of Figure 32 described above.

[0248] 37, the layer formed between oxide film 231 and oxide film 233 has a structure in which a first layer consisting of only High-k film 232A and a second layer partially including High-k film 232A are laminated. Also, in insulating layer 230, the portion of the second layer excluding High-k film 232A is formed including a portion of oxide film 233 which is the upper layer.

[0249] As described above, in the pixel 200 of FIG. 37, the insulating layer 230 has a structure in which high-k films 232A of different heights are formed in a portion corresponding to a central region 221 having a large amount of fixed charge at the center of the left and right photoelectric conversion elements 213A, 213B, and in a portion corresponding to left and right regions 222 having a small amount of fixed charge excluding the central regions.

[0250] 37, the portion of the High-k film 232A corresponding to the central region 221 in the center is higher than the portions corresponding to the left and right regions 222 excluding the central region, forming a convex structure. From this structure, it can also be said that the thickness of the oxide film 233 is different between the portion corresponding to the central region 221 and the portions corresponding to the left and right regions 222 in the insulating layer 230 in FIG.

[0251] By having such a structure, in the pixel 200 of Figure 37, when there is a phase difference shift as shown by the incident light IL in the figure, electrons photoelectrically converted near the silicon interface are accumulated in the desired left and right photoelectric conversion elements 213A, 213B, thereby improving the detection accuracy of the phase difference.

[0252] (8th example of structure) FIG. 38 is a cross-sectional view showing an eighth example of the pixel structure according to the tenth embodiment.

[0253] Figure 38, like Figure 32 described above, shows an enlarged view of a region in the cross section of pixel 200 shown in Figure 31 that includes central region 221 and left and right regions 222 of the silicon interface, but the cross-sectional structure of insulating layer 230 is different from the enlarged view of Figure 32 described above.

[0254] That is, in the insulating layer 230 of FIG. 38, the layer formed between the oxide film 231 and the oxide film 233 forms a layer consisting of only the High-k film 232A, but a part of that layer, which corresponds to the central region 221 in the center, has a structure in which it protrudes downward relative to the parts corresponding to the left and right regions 222 excluding the central portion.

[0255] As described above, in the pixel 200 of FIG. 38, the insulating layer 230 has a structure in which the thickness of the oxide film 231 differs between a portion corresponding to a central region 221 having a large amount of fixed charge at the center of the left and right photoelectric conversion elements 213A, 213B and a portion corresponding to left and right regions 222 having a small amount of fixed charge excluding the central portion.

[0256] By having such a structure, in the pixel 200 of Figure 38, when there is a phase difference shift as shown by the incident light IL in the figure, electrons photoelectrically converted near the silicon interface are accumulated in the desired left and right photoelectric conversion elements 213A, 213B, thereby improving the detection accuracy of the phase difference.

[0257] (9th example of structure) FIG. 39 is a cross-sectional view showing a ninth example of the pixel structure according to the tenth embodiment.

[0258] 31 to 38, the inter-pixel isolation portion 215 is formed of an oxide film, but the material for the inter-pixel isolation portion 215 is not limited to an oxide film and other materials such as metal can be used. Fig. 39 shows a structure in which the inter-pixel isolation portion 215A is formed by embedding a metal in place of the inter-pixel isolation portion 215 described above in the pixel 200.

[0259] Here, for example, by using DTI technology, a metal is embedded in a groove (trenches) that is dug in a square lattice shape according to the shape of a square unit pixel from the light incident surface side in a silicon layer in which a photoelectric conversion region is formed, thereby forming the inter-pixel separation section 215A. Here, for example, tungsten (W), aluminum (Al), silver (Ag), rhodium (Rh), etc. can be used as the metal.

[0260] For example, in the pixel 200 of A in FIG. 39, the incident light IL A When there is a phase difference shift as shown in FIG. 39B, when electrons photoelectrically converted near the silicon interface are accumulated in the desired left and right photoelectric conversion elements 213A, 213B due to the potential gradient, the adjacent pixels are physically separated in the silicon layer by the inter-pixel separation portion 215A, so that it is possible to prevent the electrons from flowing into the adjacent pixels. Note that, as shown in FIG. 39B, even when there is no phase difference, it is possible to similarly prevent the electrons from flowing into the adjacent pixels.

[0261] 39, by forming inter-pixel isolation portion 215A and isolating pixels of different colors with metal, it is possible to suppress color mixing in the bulk and improve the separation ratio. Note that, although oxide film and metal are described above as materials for inter-pixel isolation portion 215 (215A), other substances may be used.

[0262] In the pixel 200 of FIG. 39, when forming the inter-pixel isolation portion 215A, a groove is dug from the light incident surface side in the silicon layer 210 in which the photoelectric conversion region is formed, and a metal is embedded therein. At this time, a pinning film (negative fixed charge film) and an insulating film can be provided on the side wall of the groove. Here, the pinning film can be, for example, hafnium oxide (HfO 2 ) and tantalum oxide (Ta 2 O 5 ) can be used as the insulating film. 2 ) etc. can be used.

[0263] (10th example of structure) FIG. 40 is a cross-sectional view showing a tenth example of the pixel structure according to the tenth embodiment.

[0264] In the above-mentioned Figures 31 to 38 and Figure 39, a structure has been shown in which adjacent pixels are physically separated by inter-pixel separation portion 215 made of an oxide film or inter-pixel separation portion 215A made of a metal, but separation may also be achieved by impurities in a silicon layer.

[0265] The pixel 200 in Fig. 40 has a structure in which adjacent pixels are separated by impurity distribution inside a silicon layer without forming a physical separation part (inter-pixel separation part) between adjacent pixels. Here, in A of Fig. 40, incident light IL A FIG. 40B shows a case where the phase difference is shifted by the incident light IL B 1 shows a case where there is no phase difference deviation due to the

[0266] (11th example of structure) FIG. 41 is a cross-sectional view showing an eleventh example of the pixel structure according to the tenth embodiment.

[0267] Fig. 41 shows a cross section of the pixel 200, similar to Fig. 31 described above, but is different from the cross section of Fig. 31 described above in that a transparent electrode 241 is formed in the center of the left and right photoelectric conversion elements 213A and 213B. A FIG. 41B shows a case where the phase difference is shifted by the incident light IL B 1 shows a case where there is no phase difference deviation due to the

[0268] 41, a potential gradient can be formed from the center of the left and right photoelectric conversion elements 213A, 213B to the left and right photoelectric conversion elements 213A, 213B by applying a negative bias to the transparent electrode 241. As a result, in the pixel 200 of FIG 41, electrons photoelectrically converted near the silicon interface can be accumulated in the desired left and right photoelectric conversion elements 213A, 213B.

[0269] For example, in the pixel 200 of A in FIG. 41, the incident light IL A When there is a phase difference shift as shown in FIG. 1, a negative bias is applied to the transparent electrode 241 to form a potential gradient, whereby electrons photoelectrically converted near the silicon interface are accumulated in the desired left and right photoelectric conversion elements 213A, 213B, thereby improving the detection accuracy of the phase difference.

[0270] (Schematic diagram of electric potential distribution) FIG. 42 is a diagram showing a schematic diagram of a potential distribution of a pixel according to the tenth embodiment.

[0271] For comparison, Fig. 42B shows the potential distribution of a pixel 200 to which the present technology is applied, and Fig. 42A shows the potential distribution of a general pixel 900. Here, the potential distribution is represented by lines drawn on the left and right photoelectric conversion elements and the area between them, and the denser these lines are, the greater the potential gradient.

[0272] As shown in the potential distribution of pixel 900 in FIG. 42A, it is generally difficult to create a potential gradient in a silicon layer on the light incident surface (eg, the back side) or in the central regions of left and right photoelectric conversion elements 913A, 913B.

[0273] In contrast, in pixel 200, by changing the amount of fixed charge between central region 221 and left and right regions 222 at the silicon interface of the light incident surface (e.g., the back side), it becomes easier to create a potential gradient in the light incident surface and central region, and a potential gradient is formed from the center between the left and right photoelectric conversion elements 213A, 213B to the left and right photoelectric conversion elements 213A, 213B.

[0274] In addition, the transfer path P shown in A of FIG. A and the transfer path P shown in FIG. B respectively show the transfer paths derived from the potential distribution of pixel 900 and pixel 200. Here, when transferring electrons, there are potential and diffusion effects, and it is assumed that if the transfer takes a long time, the electrons will diffuse accordingly, and it will not be possible to accumulate the electrons in the desired photoelectric conversion element 213 (213A or 213B).

[0275] For example, in A of FIG. A However, the transfer path P is a combination of a downward path and a left-diagonally downward path, and it may take time for the electrons to be transferred and they may diffuse. B However, the path is only diagonally downward to the left, allowing electrons to be transferred quickly.

[0276] That is, in the pixel 200 in FIG. 42B, a potential gradient is created by changing the amount of fixed charge between the central region 221 and the left and right regions 222 at the silicon interface of the light incident surface (for example, the back surface side). Therefore, the transfer path P B42B, electrons photoelectrically converted near the silicon interface can be stored in the desired photoelectric conversion element 213 (213A or 213B).

[0277] The tenth embodiment has been described above.

[0278] (11) Eleventh embodiment

[0279] As described above, in solid-state imaging devices such as CMOS image sensors, a pixel structure in which multiple photoelectric conversion elements are formed directly under a single on-chip lens is adopted, and distance information is obtained based on a phase difference detection signal obtained from each pixel, making it possible to simultaneously perform imaging and distance measurement. In addition, in the pixel, an isolation structure using impurity implantation can be used between the left and right photoelectric conversion elements.

[0280] By adopting such a structure, it is possible to simultaneously obtain signals for imaging and signals for phase difference detection. However, when light incident from one on-chip lens is photoelectrically converted, a component that is subject to photoelectric conversion is generated in the part that serves as the separation wall located in the center of the left and right photoelectric conversion elements.

[0281] Since this separation wall is formed by implantation separation and has a certain width, the charges (electrons) photoelectrically converted in that region may flow to the photoelectric conversion element on the opposite side to the photoelectric conversion element on the side expected to produce a phase difference, resulting in an insufficient separation ratio and a decrease in the accuracy of phase difference detection.

[0282] Furthermore, for example, if in a pixel the separation wall located at the center of the left and right photoelectric conversion elements is made into a separation structure using a low refractive index material or the like rather than implant separation, the light incident on that area will be refracted and become more angled light, making it more likely to be incident on the photoelectric conversion elements of other adjacent pixels, which may result in optical mixing of different colors.

[0283] Therefore, in the eleventh embodiment, a structure is adopted in which a buried element isolation region with low refractive index is formed in the center portion of photoelectric conversion elements of the same color (center portion between same colors) and a buried element isolation region of metal is formed in the center portion of photoelectric conversion elements of different colors (center portion between different colors) for the pixels 300 arranged two-dimensionally in the pixel array portion 11 of the CMOS image sensor 10 (FIG. 1). By adopting such a structure, it is possible to improve the separation ratio and prevent color mixing.

[0284] The pixel structure of the eleventh embodiment will be described below with reference to FIGS.

[0285] (First example of structure) FIG. 43 is a cross-sectional view showing a first example of a pixel structure according to the eleventh embodiment.

[0286] 43, the pixel 300 has a 2PD structure, and includes an on-chip lens 311, a color filter 312, photoelectric conversion elements 313A and 313B, an inter-pixel light shielding portion 314, and an inter-pixel isolating portion 315. In FIG.

[0287] In the pixel 300, the on-chip lens 311 to the inter-pixel isolation portion 315 correspond to the on-chip lens 111, the color filter 112, the photoelectric conversion elements 113A and 113B, the inter-pixel light shielding portion 114, and the inter-pixel isolation portion 115 constituting the pixel 100 (FIG. 11, etc.) of the above-described embodiment, respectively, and therefore the description thereof will be omitted here as appropriate.

[0288] Also, for convenience of explanation, when it is necessary to particularly distinguish the color of each pixel 300, the R pixel 300 will be written as "300(R)" and the G pixel 300 will be written as "300(G)".

[0289] In the pixel 300, incident light IL collected by the on-chip lens 311 passes through a color filter 312 and is irradiated onto a photoelectric conversion region of the photoelectric conversion element 313A or the photoelectric conversion element 313B.

[0290] Here, in the G pixel 300, a low refractive index material (embedded element) is embedded on the light incident surface side of the same-color central portion 321 between the photoelectric conversion element 313A and the photoelectric conversion element 313B to form a low refractive index region 331 as an element isolation region. As the low refractive index material, for example, an oxide film, glass, or other low refractive index material can be used. More specifically, as the low refractive index material, for example, a material having a low refractive index relative to the silicon layer 310 (semiconductor layer) in which the photoelectric conversion region is formed can be used.

[0291] The cross-sectional shape of the low refractive index region 331 is tapered, forming a triangle whose width increases as it approaches the light incident surface. In the same-color central portion 321, the low refractive index material (embedded element) serving as a separation material disappears at a predetermined bulk depth (for example, about several hundreds of nm) from the light incident surface, and the region below that is separated by impurities.

[0292] Furthermore, when a G pixel 300 and an R pixel 300 are adjacent to each other on the left and right, in a different-color central portion 322 between a photoelectric conversion element 313B on the right side of the G pixel 300 and a photoelectric conversion element 313A on the left side of the R pixel 300, a groove (trench) dug from the light incident surface side according to the shape of the pixel 300 is filled with metal to form an inter-pixel separation portion 315. Here, examples of the metal that can be used include tungsten (W), aluminum (Al), silver (Ag), and rhodium (Rh).

[0293] 43 has a structure in which low refraction region 331 having an inverted triangular cross section is formed in same-color central portion 321, so that the direction of travel of light incident on low refraction region 331 is bent by the refraction surface. For example, in pixel 300, of the light incident on low refraction region 331 from an upper right direction, light is refracted by refraction surface 331A and enters photoelectric conversion element 313A on the left side, while light is refracted by refraction surface 331B and enters photoelectric conversion element 313B (arrow in the figure).

[0294] Therefore, when a focused spot of light focused by the on-chip lens 311 is incident on the low refractive index region 331 formed in the same-color central portion 321 between the left and right photoelectric conversion elements 313A and 313B, the incident light travels directly to a certain depth without being photoelectrically converted, and when it reaches the certain depth, it is incident on the photoelectric conversion element 313A or the photoelectric conversion element 313B and is photoelectrically converted. In particular, in the pixel 300 in FIG. 43, it is possible to split the light incident on the center of the light incident surface in the same-color central portion 321 into the left and right photoelectric conversion elements 313A and 313B.

[0295] Here, as mentioned above, if a separation wall is formed by implantation separation in the same-color central portion 321, there is a risk that the accuracy of phase difference detection will decrease due to electrons photoelectrically converted in the region that will become the separation wall flowing to the photoelectric conversion element on the opposite side to the photoelectric conversion element on the side expected to produce a phase difference.

[0296] 43 has a separation structure using a low refractive index region 331 formed in the same-color central portion 321, and incident light IL incident on the low refractive index region 331 is incident directly on the left and right photoelectric conversion elements 313A and 313B without being photoelectrically converted up to a certain depth, thereby making it possible to avoid such an event. As a result, in the pixel 300 in FIG. 43, the separation ratio can be improved optically and electrically, and the detection accuracy of the phase difference can be improved.

[0297] On the other hand, as mentioned above, if a separation structure is formed using a low refractive index region 331 in the same-color central portion 321, there is a risk that light incident on the low refractive index region 331 will be refracted and become light at a greater angle, which may then enter the photoelectric conversion element 313 of the adjacent pixel 300 of a different color.

[0298] 43, a separation structure using low refractive index region 331 is provided in same-color central portion 321, and inter-pixel separation portion 315 made of metal is formed in different-color central portion 322, so that light refracted by low refractive index region 331 formed in same-color central portion 321 is reflected by inter-pixel separation portion 315. As a result, optical mixture of different colors can be prevented in pixel 300 in FIG.

[0299] In the pixel 300 of FIG. 43, a groove (trench) is dug from the light incident surface side in the silicon layer 310 in which the photoelectric conversion region is formed, and a metal is filled in to form the inter-pixel separation section 315. A pinning film (negative fixed charge film) and an insulating film can be provided on the side wall of the groove. Here, the pinning film can be, for example, hafnium oxide (HfO 2 ) and tantalum oxide (Ta 2 O 5 ) can be used as the insulating film. 2 ) etc. can be used.

[0300] (Second example of structure) FIG. 44 is a cross-sectional view showing a second example of the pixel structure according to the eleventh embodiment.

[0301] The pixel 300 in Fig. 44 has a different cross-sectional shape of the same-color central portion 321 from the pixel 300 in Fig. 43. That is, in the same-color central portion 321 of the pixel 300 in Fig. 44, the separation shape (cross-sectional shape) of the tapered low refractive index region 331 extends downward with a certain width to a predetermined bulk depth (for example, about several hundreds of nm) from the light incident surface, and the shape of the region below is rectangular (vertically long).

[0302] That is, in the same-color central portion 321 of pixel 300 in FIG. 43, the region below low refractive index region 331 is not formed with a low refractive index material as a separating material, but is separated by impurities, whereas in the same-color central portion 321 of pixel 300 in FIG. 44, low refractive index region 331 extends downward by a constant width, and photoelectric conversion element 313A and photoelectric conversion element 313B are separated by the rectangular (vertically long) portion below.

[0303] 44, the triangular portion of the low refractive index region 331 and its downwardly extending portion form an inter-element separation portion, so to speak, which physically separates the photoelectric conversion element 313A from the photoelectric conversion element 313B. This prevents the output of one photoelectric conversion element 313 (313A or 313B) from being mixed with the output of the other photoelectric conversion element 313 (313B or 313A) in the pixel 300 of FIG. 44, thereby improving the accuracy of phase difference detection.

[0304] (Third example of structure) FIG. 45 is a cross-sectional view showing a third example of the pixel structure according to the eleventh embodiment.

[0305] The pixel 300 in Fig. 45 has a different cross-sectional shape of the same-color central portion 321 from the pixel 300 in Fig. 43. That is, in the same-color central portion 321 of the pixel 300 in Fig. 45, the separation shape (cross-sectional shape) of the low refractive index region 331 is tapered from the light incident surface to the opposite surface (the transistor element surface side), and is trapezoidal (a trapezoid whose lower base is shorter than its upper base).

[0306] 45, the photoelectric conversion element 313A and the photoelectric conversion element 313B are physically separated from each other by forming an inter-element separation portion, so to speak, using the trapezoidal portion in the low refractive index region 331. This prevents the output of one photoelectric conversion element 313 from being mixed with the output of the other photoelectric conversion element 313 in the pixel 300 in FIG. 45, thereby improving the accuracy of phase difference detection.

[0307] (Fourth example of structure) FIG. 46 is a plan view showing a fourth example of the pixel structure according to the eleventh embodiment.

[0308] In the plan view shown in Fig. 46, the X-X' cross section corresponds to the cross section of pixel 300 in Fig. 43. That is, in pixel 300 in Fig. 46, same-color central portion 321 including low refractive index region 331 is formed between photoelectric conversion element 313A and photoelectric conversion element 313B, and has a rectangular shape (vertically long shape) when viewed from the light incident surface side.

[0309] Here, the dotted line in the figure represents incident light IL. When the light collected by the on-chip lens 311 enters the low refractive index region 331, the incident light travels directly without being photoelectrically converted up to a certain depth, and when it reaches the certain depth, it enters the photoelectric conversion element 313A or the photoelectric conversion element 313B and is photoelectrically converted.

[0310] Note that here, the plan view shown in Figure 46 corresponds to the cross-sectional view of pixel 300 in Figure 43, but similarly, in pixel 300 in Figure 44 or pixel 300 in Figure 45, same-color central portion 321 (low refractive index region 331) is formed between photoelectric conversion element 313A and photoelectric conversion element 313B.

[0311] (Fifth example of structure) FIG. 47 is a plan view showing a fifth example of the pixel structure according to the eleventh embodiment.

[0312] In the plan view shown in Fig. 47, the X-X' cross section corresponds to the cross section of pixel 300 in Fig. 43. That is, in pixel 300 in Fig. 47, same-color central portion 321 including low refractive index region 331 is formed for four photoelectric conversion elements 313, namely photoelectric conversion element 313A, photoelectric conversion element 313B, photoelectric conversion element 313C, and photoelectric conversion element 313D, and has a rhombus shape when viewed from the light incident surface side.

[0313] Here, the dotted line in the figure represents incident light IL. When the light focused by the on-chip lens 311 enters the low refractive index region 331, the incident light travels directly without being photoelectrically converted up to a certain depth, and when it reaches the certain depth, it enters one of the photoelectric conversion elements 313A to 313D and is photoelectrically converted.

[0314] Note that, here, the plan view shown in Figure 47 corresponds to the cross-sectional view of pixel 300 in Figure 43, but the same-color central portion 321 (low refractive area 331) can be formed for the four photoelectric conversion elements 313 in the same manner for pixel 300 in Figure 44 or pixel 300 in Figure 45.

[0315] Furthermore, the separation layout by the same-color central portion 321 (the low refractive index region 331) shown in Figures 46 and 47 is just one example, and other separation layouts other than a rectangular shape for two photoelectric conversion elements 313 or a diamond shape for four photoelectric conversion elements 313 may be used.

[0316] (Sixth example of structure) FIG. 48 is a cross-sectional view showing a sixth example of the pixel structure according to the eleventh embodiment.

[0317] The pixel 300 in Fig. 48 has a different cross-sectional shape of the different color central portion 322 from the pixel 300 in Fig. 44. That is, in the different color central portion 322 of the pixel 300 in Fig. 48, a low refractive index region 341 made of a low refractive index material is formed in the region (region in the depth direction) below the inter-pixel separation portion 315 made of metal.

[0318] More specifically, a separation section for separating pixels of different colors is formed by filling a material into a groove (trench) dug into silicon in which a photoelectric conversion region is formed. In pixel 300 of FIG. 48, low refractive index region 341 is formed by filling a front side trench with a low refractive index material, and inter-pixel separation section 315 is formed by filling a back side trench with a metal.

[0319] In the pixel 300 of FIG. 48, the different color central portion 322 has a structure that combines the inter-pixel separation portion 315 and the low refractive index region 341, thereby providing separation between pixels of different colors, such as between the photoelectric conversion element 313B on the right side of the G pixel 300 and the photoelectric conversion element 313A on the left side of the R pixel 300 shown in FIG. 48.

[0320] The eleventh embodiment has been described above.

[0321] (12) Twelfth embodiment

[0322] As described above, in a solid-state imaging device having pixels in which a plurality of photoelectric conversion elements are formed directly under a single on-chip lens, distance information can be obtained based on a signal for detecting a phase difference obtained from each pixel.

[0323] However, in a typical pixel structure, a trade-off occurs between the separation ratio and color mixing, making it difficult to improve the accuracy of phase difference detection while suppressing color mixing. Conventionally, to resolve this trade-off, phase difference information is simply obtained using only the bulk, or for high-precision detection, the separation ratio is increased by using an optical waveguide without using an on-chip lens. However, there has been a demand for further improvement in the accuracy of phase difference detection while suppressing color mixing.

[0324] Therefore, in the twelfth embodiment, a structure in which an on-chip lens is made of a plurality of materials having different refractive indices is adopted as the pixels 400 arranged two-dimensionally in the pixel array unit 11 of the CMOS image sensor 10 (FIG. 1). By adopting such a structure, it is possible to improve the accuracy of phase difference detection while suppressing color mixing. Here, the color mixing includes color mixing between a plurality of photoelectric conversion elements formed directly under a single on-chip lens.

[0325] The pixel structure of the twelfth embodiment will be described below with reference to FIGS.

[0326] (First example of structure) FIG. 49 is a cross-sectional view showing a first example of a pixel structure according to the twelfth embodiment.

[0327] In FIG. 49, the pixel 400 has a 2PD structure, and includes an on-chip lens 411, a color filter 412, photoelectric conversion elements 413A and 413B, an inter-pixel light shielding portion 414, and an inter-pixel isolation portion 415.

[0328] In the pixel 400, the on-chip lens 411 to the inter-pixel isolation portion 415 correspond to the on-chip lens 111, the color filter 112, the photoelectric conversion elements 113A and 113B, the inter-pixel light shielding portion 114, and the inter-pixel isolation portion 115 constituting the pixel 100 (FIG. 11, etc.) of the above-described embodiment, respectively, and therefore the description thereof will be omitted here as appropriate.

[0329] Also, for ease of explanation, when it is necessary to particularly distinguish the colors of each pixel 400, the R pixel 400 will be represented as "400(R)", the G pixel 400 as "400(G)", and the B pixel 400 as "400(B)".

[0330] In the pixel 400, the on-chip lens 411 is composed of a member 411A and a member 411B, which are two types of materials with different refractive indices. In the on-chip lens 411, the member 411B has a V-shaped recess, and a part of the member 411A (the part opposite the light incident surface) is embedded in the V-shaped portion.

[0331] That is, member 411A (first member) includes a curved surface onto which light is incident and a portion corresponding to the V-shaped portion of member 411B, and member 411B (second member) includes a surface opposite to the curved surface onto which light is incident and a portion having a V-shape. Note that, although a case where the joint between members 411A and 411B is V-shaped will be described here, the shape of the joint may be other shapes than a V-shape.

[0332] For example, the member 411A is made of a high-refractive index material (high-n material) having a higher refractive index than the member 411B. On the other hand, for example, the member 411B is made of a low-refractive index material (low-n material) having a lower refractive index than the member 411A. In addition, an anti-reflection film 431 is formed on the light incident surface of the on-chip lens 411.

[0333] In the pixel 400, incident light IL incident on the on-chip lens 411 is refracted at the light incident surface of the member 411A, as shown by the arrow in FIG. 49, and then refracted at the boundary between the members 411A and 411B, and is irradiated to the photoelectric conversion region of the photoelectric conversion element 413A.

[0334] As described above, in the pixel 400 of FIG. 49, the on-chip lens 411 is composed of members 411A and 411B having different refractive indices, so that the light incident on each of the photoelectric conversion elements 413A and 413B is accumulated in the desired left or right photoelectric conversion element 413A or 413B without mixing (without color mixing).

[0335] FIG. 50 shows the output results according to the incident angle of light for each photoelectric conversion element 413 in the pixel 400 in FIG.

[0336] 50, for comparison, output results of left and right photoelectric conversion elements 913A and 913B (conventional structure) of a general pixel 900 are also shown along with output results of the photoelectric conversion elements 413A and 413B (structure of the present technology) of the pixel 400 in FIG. 49. However, in the pixel 900, the structure of the on-chip lens 911 is different from the structure of the on-chip lens 411 of the pixel 400. That is, in the pixel 900, the on-chip lens 911 is not composed of a plurality of materials having different refractive indices.

[0337] That is, in Fig. 50, for pixel 400 in Fig. 49, the output of left photoelectric conversion element 413A is represented by solid curve A1, and the output of right photoelectric conversion element 413B is represented by dotted curve B1. Also, for general pixel 900, the output of left photoelectric conversion element 913A is represented by solid curve A2, and the output of right photoelectric conversion element 913B is represented by dotted curve B2.

[0338] Here, the curve A1 corresponding to the output of the left photoelectric conversion element 413A and the curve B1 corresponding to the output of the right photoelectric conversion element 413B have the same output value when the incident angle θi is 0 degrees, that is, when light is incident from directly above. In other words, the curves A1 and B1 have a line-symmetrical relationship with the output when the incident angle θi = 0 as the axis of symmetry.

[0339] Similarly, curve A2 corresponding to the output of photoelectric conversion element 913A on the left side and curve B2 corresponding to the output of photoelectric conversion element 913B on the right side are in an axisymmetric relationship with respect to the output when the incident angle θi = 0.

[0340] In this case, when the curves A1 and B1 of the pixel 400 in FIG. 49 are compared with the curves A2 and B2 of the general pixel 900, the following relationship is found.

[0341] In other words, when the incident angle θi is negative and attention is paid to curves A1 and A2, the peak values ​​of the output of photoelectric conversion element 413A and the output of photoelectric conversion element 913A are approximately the same, but the output of photoelectric conversion element 413A is mixed with the output of photoelectric conversion element 413B, while the output of photoelectric conversion element 913A is mixed with the output of photoelectric conversion element 913B.

[0342] At this time, if we look at curves B1 and B2, the output of photoelectric conversion element 413B is smaller than the output of photoelectric conversion element 913B, and therefore the output of photoelectric conversion element 413B mixed with the output of photoelectric conversion element 413A is reduced.

[0343] On the other hand, when the incident angle θi is positive and attention is paid to curves B1 and B2, the peak values ​​of the output of photoelectric conversion element 413B and the output of photoelectric conversion element 913B are approximately the same, but the output of photoelectric conversion element 413A is mixed into the output of photoelectric conversion element 413B, while the output of photoelectric conversion element 913B is mixed with the output of photoelectric conversion element 913A.

[0344] At this time, if we look at curves A1 and A2, the output of photoelectric conversion element 413A is smaller than the output of photoelectric conversion element 913A, and therefore the output of photoelectric conversion element 413A mixed with the output of photoelectric conversion element 413B is reduced.

[0345] 49, by configuring the on-chip lens 411 with members 411A and 411B having different refractive indices, the output of one photoelectric conversion element 413 (413A or 413B) is not mixed with the output of the other photoelectric conversion element 413 (413B or 413A), thereby improving the accuracy of phase difference detection. As a result, an electronic device equipped with the CMOS image sensor 10 can achieve more accurate autofocus.

[0346] (Second example of structure) FIG. 51 is a cross-sectional view showing a second example of the pixel structure according to the twelfth embodiment.

[0347] 51 is different from the pixel 400 in Fig. 49 in that an inter-element isolation portion 416 is formed between left and right photoelectric conversion elements 413A and 413B, and the cross-sectional shape of the on-chip lens 411 is different. That is, in the pixel 400 in Fig. 51, the on-chip lens 411 includes a member 411A and a member 411B, which are two types of materials with different refractive indexes, and further includes a member 411C made of a different material.

[0348] In the on-chip lens 411, the member 411B has a V-shaped recess on the light incident surface side, and a part of the member 411A (the part opposite the light incident surface) is embedded in the V-shaped portion. In the on-chip lens 411, the member 411B also has a V-shaped recess on the opposite side to the light incident surface, and the member 411C (all of it) is embedded in the V-shaped portion.

[0349] Here, when members 411A and 411C are formed to have a V-shaped cross section relative to member 411B, the apexes of the V-shapes are in contact with each other and the V-shaped cross section of member 411C is smaller than the V-shaped cross section of member 411A; however, the cross-sectional shape shown in FIG. 51 is only one example, and other shapes may be adopted.

[0350] Furthermore, in the on-chip lens 411, when the member 411A is made of a high refractive index material (high-n material) and the member 411B is made of a low refractive index material (low-n material), the member 411C can be made of a material with a refractive index that can reduce the amount of light incident on the inter-element isolation portion 416 formed in the silicon layer 410. In this case, the refractive index of the member 411C can be different from those of the members 411A and 411B. The refractive index of the member 411C may be the same as that of the member 411A.

[0351] In this manner, in the pixel 400 of FIG. 51, when an inter-element isolation portion 416 is provided between the left and right photoelectric conversion elements 413A and 413B, the on-chip lens 411 has a structure including the member 411C in addition to the members 411A and 411B, so that the amount of light incident on the inter-element isolation portion 416 can be reduced.

[0352] (Third example of structure) FIG. 52 is a cross-sectional view showing a third example of the pixel structure according to the twelfth embodiment.

[0353] The pixel 400 in FIG. 52 is the same as the pixel 400 in FIG. 51 in that an inter-element isolation portion 416 is provided and the on-chip lens 411 is composed of components 411A to 411C, but differs in that the height of the on-chip lens 411 in the optical axis direction (stacking direction) is optimized for each color depending on the material of the on-chip lens 411.

[0354] In FIG. 52, the refractive indexes of the members 411A, 411B, and 411C in each pixel 400 are n 1 ,n 2 ,n 3 In the G pixel 400, the on-chip lens 411 has a radius of curvature r G and its height is h G Similarly, in the R pixel 400, the radius of curvature and the height of the on-chip lens 411 are expressed as r R ,h R In the B pixel 400, the radius of curvature and the height of the on-chip lens 411 are expressed as r B ,h B It is expressed as:

[0355] Here, the height h G and the height h at R pixel 400 R and the height h at the B pixel 400 B is the refractive index n of the material of the on-chip lens 411, that is, the members 411A to 411C. 1 ,n 2 ,n 3 Each color is optimized to suit your needs.

[0356] For example, the height h of the on-chip lens 411 for each color G ,h R ,h B However, if chromatic aberration is taken into consideration, the relationship can be expressed as the following formula (1).

[0357] h R > h G > h B (1)

[0358] Although the above describes an example in which the height h of the on-chip lens 411 is adjusted as a parameter for optimizing for each color, other parameters may be used. For example, when adjusting the radius of curvature r of the on-chip lens 411, a relationship such as the following formula (2) can be established in consideration of chromatic aberration.

[0359] r R > r G > r B (2)

[0360] In this manner, in the pixel 400 of FIG. 52, by optimizing parameters such as the height and radius of curvature of the on-chip lens 411 for each color according to the material (the refractive index of multiple types of components) of the on-chip lens 411, it is possible to improve the quantum efficiency and separation ratio of each color, or suppress color mixing, for example.

[0361] In FIG. 52, the angle between the boundary surface of the member 411B with the member 411A and the horizontal plane is θ G Similarly, in the R pixel 400 and the B pixel 400, the angle between the boundary surface of the member 411B with the member 411A and the horizontal plane is represented as θ R ,θ B For example, these angles θ G ,θ R ,θ B may be optimized using as a parameter other than the height h and the curvature radius r of the on-chip lens 411 described above.

[0362] (Fourth example of structure) FIG. 53 is a cross-sectional view showing a fourth example of the pixel structure according to the twelfth embodiment.

[0363] The pixel 400 in FIG. 53 differs from the pixel 400 in FIG. 49 in that an inter-element isolation part 416 is provided, and a control member 421 is provided between the member 411A and the member 411B in the on-chip lens 411.

[0364] The control member 421 is composed of, for example, a photonic crystal. A photonic crystal is a nanostructure in which the refractive index changes periodically. In the on-chip lens 411, the control member 421 is formed between the member 411A and the member 411B, thereby forming a structure capable of controlling the incidence angle dependency of light.

[0365] That is, by providing control member 421 as a photonic crystal in pixel 400, for example, it is possible to provide a structure in which incident light from the left side in the figure is totally reflected so that the light does not enter photoelectric conversion element 413A on the left side, or a structure in which incident light from the right side in the figure is totally reflected so that the light does not enter photoelectric conversion element 413B on the right side. That is, pixel 400 has a structure that efficiently utilizes the incidence angle dependency of the photonic crystal to further enhance the incidence angle dependency.

[0366] As described above, in the pixel 400 of FIG. 53, the control member 421 as a photonic crystal is formed between the member 411A and the member 411B of the on-chip lens 411 to provide a structure capable of controlling the incidence angle dependence of light, thereby making it possible to improve the accuracy of phase difference detection while suppressing color mixing.

[0367] (Fifth example of structure) FIG. 54 is a cross-sectional view showing a fifth example of the pixel structure according to the twelfth embodiment.

[0368] Pixel 400 in FIG. 54 differs from pixel 400 in FIG. 53 in that color filters 412 corresponding to the respective colors are removed and control members 421 (421R, 421G, 421B) have a light separation function.

[0369] The control members 421 (421R, 421G, 421B) are composed of, for example, photonic crystals. In a photonic crystal, only light of a specific wavelength resonates with a periodic structure and is reflected or transmitted, and this characteristic can be utilized to provide the control members with a spectroscopic function similar to that of a color filter.

[0370] That is, in the G pixel 400 of FIG. 54, when the control member 421G as a photonic crystal is formed between the members 411A and 411B, the photonic crystal structure is made to function as a filter that transmits green (G) wavelength components, thereby eliminating the need for a G color filter 412.

[0371] Similarly, in the R pixel 400 in Fig. 54, when the control member 421R is formed, the photonic crystal structure is made to function as a filter that transmits red (R) wavelength components, resulting in a structure without an R color filter 412. Similarly, in the B pixel 400 in Fig. 54, the photonic crystal structure is made to function as a filter that transmits blue (B) wavelength components, resulting in a structure without a B color filter 412.

[0372] In this way, in pixel 400 of FIG. 54, when control member 421 as a photonic crystal is provided, a photonic crystal structure is used to make it function equivalently to color filters of each color, thereby making it possible to efficiently utilize the incidence angle dependence of the photonic crystal and not only to obtain a structure that further enhances the incidence angle dependence, but also to obtain a structure that does not require color filter 412.

[0373] (Sixth example of structure) FIG. 55 is a plan view showing a sixth example of the pixel structure according to the twelfth embodiment.

[0374] The pixels 400 are arranged two-dimensionally (in a matrix) in the pixel array section 11 (FIG. 1). Of the pixels arranged in the pixel array section 11 (FIG. 1), it is possible that not only all the pixels have the same structure as the pixel 400, but also some of the pixels have the same structure as the pixel 400.

[0375] For example, as shown in FIG. 55, even when a pixel array section 11 adopts an arrangement pattern in which shared pixels, in which neighboring pixels of the same color (4 pixels of the same color, 2 × 2) share a pixel circuit, are regularly arranged, some of the pixels can have a structure similar to that of pixel 400.

[0376] However, in the pixel array shown in Fig. 55, each pixel 400 has a structure having one photoelectric conversion element (1PD structure). Here, in order to distinguish it from the pixel 400 having the above-mentioned 2PD structure, the pixel 400 having the 1PD structure will be referred to as pixel 400 (1PD).

[0377] Here, for example, in the pixel array shown in Fig. 55, an elliptical on-chip lens 411E is formed for G pixel 400-11 (1PD) and G pixel 400-12 (1PD) arranged in the same row. This on-chip lens 411E has a structure made of multiple types of materials with different refractive indices, similar to the above-mentioned on-chip lens 411 (Fig. 49, etc.).

[0378] That is, one on-chip lens 411E is provided with one photoelectric conversion element 413 of G pixel 400-11 (1PD) (e.g., equivalent to photoelectric conversion element 413A in FIG. 49) and one photoelectric conversion element 413 of G pixel 400-12 (1PD) (e.g., equivalent to photoelectric conversion element 413B in FIG. 49). In this case, phase difference detection is performed using the outputs of the photoelectric conversion element 413 of G pixel 400-11 (1PD) and the photoelectric conversion element 413 of G pixel 400-12 (1PD) arranged in the same row.

[0379] Similarly, for G pixels 400-21 (1PD) and 400-22 (1PD) arranged in the same row, an elliptical on-chip lens 411E is formed, and phase difference detection is performed using the outputs of the photoelectric conversion elements 413 (e.g., corresponding to photoelectric conversion elements 413A and 413B in FIG. 49) of those G pixels 400 (1PD).

[0380] Furthermore, for example, an elliptical on-chip lens 411E may be formed in the column direction, such as G pixel 400-33 (1PD) and G pixel 400-43 (1PD) or G pixel 400-34 (1PD) and G pixel 400-44 (1PD) arranged in the same column.

[0381] In the pixel array shown in FIG. 55, the case has been described in which two G pixels 400 (1PD) are arranged relative to the elliptical on-chip lens 411E. However, an R pixel 400 (1PD) and a B pixel 400 (1PD) may be arranged relative to the elliptical on-chip lens 411E in the row direction or column direction.

[0382] (Seventh example of structure) FIG. 56 is a plan view showing a seventh example of the pixel structure according to the twelfth embodiment.

[0383] As shown in Fig. 56, even when the Bayer arrangement is adopted in the pixel array unit 11 (Fig. 1), some pixels can have the same structure as the pixel 400. However, even in the pixel arrangement shown in Fig. 56, each pixel 400 has a structure having one photoelectric conversion element (1PD structure), and the pixel 400 of this 1PD structure will be referred to as pixel 400 (1PD).

[0384] Here, for example, in the pixel array shown in Fig. 56, an elliptical on-chip lens 411E is formed for the G pixel 400-22 (1PD) and the G pixel 400-32 (1PD) arranged in the same column. This on-chip lens 411E has a structure made of multiple types of materials with different refractive indices, similar to the above-mentioned on-chip lens 411 (Fig. 49, etc.).

[0385] That is, one on-chip lens 411E is provided with one photoelectric conversion element 413 of a G pixel 400-22 (1PD) (e.g., corresponding to photoelectric conversion element 413A in FIG. 49) and one photoelectric conversion element 413 of a G pixel 400-32 (1PD) (e.g., corresponding to photoelectric conversion element 413B in FIG. 49), and phase difference detection is performed using the outputs of the photoelectric conversion elements 413 of the G pixels 400 (1PD).

[0386] Similarly, for G pixel 400-27 (1PD) and G pixel 400-37 (1PD) arranged in the same column, an elliptical on-chip lens 411E is formed, and phase difference detection is performed using the outputs of the photoelectric conversion elements 413 of those G pixels 400 (e.g., corresponding to photoelectric conversion elements 413A and 413B in FIG. 49).

[0387] Furthermore, an elliptical on-chip lens 411E may be formed in the row direction, such as G pixel 400-71 (1PD) and G pixel 400-72 (1PD) or G pixel 400-66 (1PD) and G pixel 400-67 (1PD) arranged in the same row.

[0388] In the Bayer array shown in FIG. 56, the case has been described in which two G pixels 400 (1PD) are arranged relative to the elliptical on-chip lens 411E. However, an R pixel 400 (1PD) and a B pixel 400 (1PD) may be arranged relative to the elliptical on-chip lens 411E in the row direction or column direction.

[0389] The twelfth embodiment has been described above.

[0390] (13) Thirteenth embodiment

[0391] FIG. 57 shows a structure of pixels arranged two-dimensionally in a pixel array portion of a CMOS image sensor.

[0392] 57, a pixel 900 has a 2PD structure having a photoelectric conversion element 913A and a photoelectric conversion element 913B. In the photoelectric conversion elements 913A and 913B, charges corresponding to each color component are generated from light that is collected by an on-chip lens 911 and transmitted through a color filter that transmits the wavelengths of each color of red (R), green (G), or blue (B).

[0393] In the pixel 900, the charges generated by the photoelectric conversion element 913A and the photoelectric conversion element 913B are read out via a transfer gate and used as information for phase difference detection.

[0394] Incidentally, in pixel 900, a structure can be adopted in which a physical separator is formed between the left and right photoelectric conversion elements 913 in order to prevent the output of one photoelectric conversion element 913 from being mixed with the output of the other photoelectric conversion element 913.

[0395] FIG. 58 shows a pixel structure in which a physical separator is provided between the left and right photoelectric conversion elements.

[0396] 58, an inter-element separator 916 is formed between photoelectric conversion element 913A and photoelectric conversion element 913B, physically separating them. By forming the inter-element separator 916 in this manner, the output of one photoelectric conversion element 913 is prevented from being mixed with the output of the other photoelectric conversion element 913, thereby improving the accuracy of phase difference detection.

[0397] However, in pixel 900, if an inter-element isolation portion 916 is formed between photoelectric conversion element 913A and photoelectric conversion element 913B from the light incident surface side (rear surface side) using DTI technology in order to improve the phase difference characteristics, the focused spot is located directly above the processed surface, and light scattering (arrow SL in Figure 58) occurs from the processed interface, which may degrade the spectral characteristics and result in a degraded captured image.

[0398] Therefore, in the thirteenth embodiment, a structure is adopted in which a vertical transistor is formed in the center portion (center portion between same colors) of photoelectric conversion elements of the same color as the pixels 500 arranged two-dimensionally in the pixel array portion 11 of the CMOS image sensor 10 (FIG. 1). By adopting such a structure, it is possible to optically separate the incident light into the desired left and right photoelectric conversion elements more efficiently.

[0399] The pixel structure of the thirteenth embodiment will be described below with reference to FIGS.

[0400] (First example of structure) FIG. 59 is a cross-sectional view showing a first example of a pixel structure according to the thirteenth embodiment.

[0401] 59, the pixel 500 has a 2PD structure, and includes an on-chip lens 511, a color filter 512, photoelectric conversion elements 513A and 513B, an inter-pixel light shielding portion 514, and an inter-pixel isolation portion 515.

[0402] In the pixel 500, the on-chip lens 511 to the inter-pixel isolation portion 515 correspond to the on-chip lens 111, the color filter 112, the photoelectric conversion elements 113A and 113B, the inter-pixel light shielding portion 114, and the inter-pixel isolation portion 115 constituting the pixel 100 (FIG. 11, etc.) of the embodiment described above, respectively, and therefore, description thereof will be omitted here as appropriate.

[0403] In the pixel 500, incident light IL collected by the on-chip lens 511 passes through a color filter 512 and is irradiated onto a photoelectric conversion region of the photoelectric conversion element 513A or the photoelectric conversion element 513B.

[0404] Here, in the pixel 500, in the same-color central portion 521 between the photoelectric conversion element 513A and the photoelectric conversion element 513B, a vertical transistor 531 is formed in the silicon layer 510 from the surface (front surface side) opposite to the light incident surface. That is, here, in addition to the transfer transistors 151 provided for each of the photoelectric conversion elements 513A and 513B, the vertical transistor 531 is provided between these elements.

[0405] In this way, in the same-color central portion 521, instead of forming an inter-element separation portion from the light incident surface (rear side), the vertical transistor 531 is formed from the opposite surface (front side), thereby achieving efficient optical separation for the left and right photoelectric conversion elements 513A, 513B without concentrating light directly above the processing surface.

[0406] Here, the function of the vertical transistor 531 formed in the same-color central portion 521 may be utilized. That is, by applying a voltage (for example, a positive voltage) to the vertical transistor 531, it becomes possible to generate a blooming path (channel) between the photoelectric conversion element 513A and the photoelectric conversion element 513B (above the vertical transistor 531). In the pixel 500, the charges accumulated in the left and right photoelectric conversion elements 513A and 513B can be exchanged via this blooming path.

[0407] Here, pixel 500 can be used both as a pixel for image acquisition and as a pixel for phase difference detection, and therefore functions as a pixel for phase difference detection during autofocusing, while functioning as a pixel for image acquisition during imaging after autofocusing is completed.

[0408] When the pixel 500 functions as a pixel for acquiring an image, for example, when the charge stored in one of the left and right photoelectric conversion elements 513 (513A or 513B) of the left and right photoelectric conversion elements 513A and 513B is about to saturate (when the charges generated by the left and right photoelectric conversion elements 513A and 513B are unbalanced), the charge is stored in the other photoelectric conversion element 513 (513B or 513A) via the blooming path, thereby preventing the charge from saturating. This makes it possible to control the output linearity in the pixel 500 by controlling the voltage to the vertical transistor 531.

[0409] In the pixel 500, in the different color central portion 522 between the photoelectric conversion elements 513A and 513B and the photoelectric conversion elements of the adjacent pixels, an inter-pixel separator 515 made of metal or the like is formed from the light incident surface (rear surface side) in the silicon layer 510. Here, the metal may be, for example, tungsten (W), aluminum (Al), silver (Ag), or rhodium (Rh).

[0410] In the pixel 500 of FIG. 59, when forming the inter-pixel separation portion 515, a groove is dug from the light incident surface side in the silicon layer 510 in which the photoelectric conversion region is formed, and a metal is embedded therein. At this time, a pinning film (negative fixed charge film) and an insulating film can be provided on the side wall of the groove. Here, the pinning film can be, for example, hafnium oxide (HfO 2 ) and tantalum oxide (Ta 2 O 5 ) can be used as the insulating film. 2 ) etc. can be used.

[0411] In this manner, in the pixel 500 of FIG. 59, by forming the vertical transistor 531 on the surface opposite the light incident surface (front surface side) in the same-color central portion 521 between the photoelectric conversion element 513A and the photoelectric conversion element 513B, a groove portion (trench) can be formed without exposing the processed surface on the light receiving surface side of the photoelectric conversion elements 513A and 513B, thereby obtaining high phase difference separation characteristics.

[0412] (Second example of structure) FIG. 60 is a cross-sectional view showing a second example of the pixel structure according to the thirteenth embodiment.

[0413] 60 is different from the pixel 500 in FIG. 59 in that a vertical transistor 532 is formed in the central portion 522 between different colors instead of the inter-pixel isolation portion 515. In the pixel 500 in FIG.

[0414] That is, in the pixel 500 of Figure 60, a vertical transistor 531 is formed in the same-color central portion 521 from the surface opposite the light incident surface (front side), and a vertical transistor 532 is also formed in the different-color central portion 522 from the surface opposite the light incident surface (front side).

[0415] In the different color central portion 522, instead of forming an inter-pixel separation portion from the light incident surface (rear side), a vertical transistor 532 is formed from the opposite surface (front side). Although this is inferior to a structure in which an inter-pixel separation portion is formed, it is possible to maintain the effect of suppressing color mixing caused by long wavelength light.

[0416] Here, the function of the vertical transistor 532 formed in the central portion 522 between different colors may be utilized. That is, by applying a voltage (e.g., a negative voltage) to the vertical transistor 532, an electric charge (negative electric charge) is generated in the silicon layer 510, and pinning can be strengthened. As a result, white spots can be suppressed. Furthermore, here too, by applying a voltage (e.g., a positive voltage) to the vertical transistor 531 formed in the central portion 521 between the same colors, it becomes possible to control the output linearity of the left and right photoelectric conversion elements 513A and 513B.

[0417] In this manner, in the pixel 500 of FIG. 60, by forming the vertical transistor 531 and the vertical transistor 532, respectively, on the surface opposite to the light incident surface (front surface side) in the same-color central portion 521 and the different-color central portion 522, it is possible to obtain high phase difference separation characteristics, and to achieve enhanced pinning and control of output linearity while maintaining the effect of suppressing color mixing due to long-wavelength light.

[0418] (Third example of structure) FIG. 61 is a cross-sectional view showing a third example of the pixel structure according to the thirteenth embodiment.

[0419] 59, the pixel 500 in FIG. 61 has a vertical transistor 532 formed not only in the same-color central portion 521 but also in the different-color central portion 522. In the pixel 500 in FIG.

[0420] That is, in the pixel 500 of Figure 61, in the central portion 522 between different colors, an inter-pixel separator 515 made of metal or the like is formed on the light incident surface (rear side), and a vertical transistor 532 is formed on the opposite surface (front side).

[0421] By adopting such a structure, the effect of suppressing color mixing can be improved by the amount of the vertical transistor 532 further formed in the different-color central portion 522, compared to the case where only the inter-pixel separation portion 541 is simply formed.

[0422] Also here, pinning can be strengthened and white spots can be suppressed by applying a voltage (e.g., a negative voltage) to the vertical transistor 532 using the function of the vertical transistor 532 formed in the different-color central portion 522. Note that, by applying a voltage (e.g., a positive voltage) to the vertical transistor 531 formed in the same-color central portion 521, it is possible to control the output linearity of the left and right photoelectric conversion elements 513A and 513B.

[0423] In this manner, in the pixel 500 of FIG. 61, a pixel separation section 515 is formed in the different color central section 522 from the light incident surface (rear side), and vertical transistors 531 and 532 are formed in the same color central section 521 and the different color central section 522 from the surface opposite the light incident surface (front side), thereby obtaining high phase difference separation characteristics, further enhancing the effect of suppressing color mixing, and further realizing enhanced pinning and control of output linearity.

[0424] The thirteenth embodiment has been described above.

[0425] <4. Pixel circuit configuration>

[0426] FIG. 62 is a diagram showing a circuit configuration of the pixel 100 in each embodiment.

[0427] 62, a floating diffusion region (FD) is shared by two pixels 100 provided at the top and bottom of the figure. However, each pixel 100 has a 2PD structure having a photoelectric conversion element 113A and a photoelectric conversion element 113B, and shares one on-chip lens 111 and one color filter 112. Also, the transfer transistors 151A and 151B correspond to the transfer gates 151A and 151B described above.

[0428] The anode of the photodiode serving as the photoelectric conversion element 113A is grounded, and the cathode of the photodiode is connected to the source of the transfer transistor 151A. The drain of the transfer transistor 151A is connected to the source of the reset transistor 152 and the gate of the amplification transistor 153, respectively.

[0429] The anode of the photodiode serving as the photoelectric conversion element 113B is grounded, and the cathode of the photodiode is connected to the source of the transfer transistor 151B. The drain of the transfer transistor 151B is connected to the source of the reset transistor 152 and the gate of the amplification transistor 153, respectively.

[0430] The connection points between the drains of the transfer transistors 151A and 151B of the two upper pixels, the source of the reset transistor 152, and the gate of the amplification transistor 153 form a floating diffusion region (FD) 161. Similarly, the connection points between the drains of the transfer transistors 151A and 151B of the two lower pixels, the source of the reset transistor 152, and the gate of the amplification transistor 153 form a floating diffusion region (FD) 161.

[0431] The drain of the reset transistor 152 and the source of the amplification transistor 153 are connected to a power supply. The drain of the amplification transistor 153 is connected to the source of the selection transistor 154, and the drain of the selection transistor 154 is connected to the vertical signal line 22.

[0432] The gates of the transfer transistors 151A and 151B, the gate of the reset transistor 152, and the gate of the selection transistor 154 are each connected to the vertical drive circuit 12 (FIG. 1) via a pixel drive line 21, and are each supplied with a pulse as a drive signal.

[0433] Next, the basic function of the pixel 100 shown in FIG. 62 will be described.

[0434] The reset transistor 152 turns on / off the discharge of the charge accumulated in the floating diffusion region (FD) 161 in accordance with a drive signal RST input to the gate of the reset transistor 152.

[0435] The photoelectric conversion element 113A converts incident light into an electric charge, generates an electric charge according to the amount of light, and accumulates the electric charge. The transfer transistor 151A turns on / off the transfer of the electric charge from the photoelectric conversion element 113A to the floating diffusion region (FD) 161 in accordance with a drive signal TRG input to the gate of the transfer transistor 151A.

[0436] The photoelectric conversion element 113B converts incident light into an electric charge, generates an electric charge according to the amount of light, and accumulates the electric charge. The transfer transistor 151B turns on / off the transfer of the electric charge from the photoelectric conversion element 113B to the floating diffusion region (FD) 161 in accordance with a drive signal TRG input to the gate of the transfer transistor 151B.

[0437] The floating diffusion region (FD) 161 has a function of accumulating charges transferred from the photoelectric conversion element 113A via the transfer transistor 151A or charges transferred from the photoelectric conversion element 113B via the transfer transistor 151B. The potential of the floating diffusion region (FD) 161 is modulated according to the amount of accumulated charges.

[0438] The amplifying transistor 153 operates as an amplifier that receives as an input signal the potential fluctuation of a floating diffusion region (FD) 161 connected to its gate, and outputs an output signal voltage to the vertical signal line 22 via the selection transistor 154 .

[0439] The selection transistor 154 turns on / off the output of the voltage signal from the amplification transistor 153 to the vertical signal line 22 in accordance with a drive signal SEL input to the gate of the selection transistor 154.

[0440] As described above, the pixel 100 having the 2PD structure is driven in accordance with the drive signals (TRG, RST, SEL) supplied from the vertical drive circuit 12 (FIG. 1).

[0441] In addition, in Figure 62, the circuit configuration of the pixel 100 of the first to ninth embodiments has been described, but a similar circuit configuration can be adopted for the pixel 200 of the tenth embodiment, the pixel 300 of the eleventh embodiment, the pixel 400 of the twelfth embodiment, or the pixel 500 of the thirteenth embodiment.

[0442] <5. Modifications>

[0443] (Examples of combinations of embodiments) Of the nine embodiments described above, each may of course stand alone as an independent embodiment, and it is also possible to adopt a form in which all or part of multiple embodiments are combined to the extent possible.

[0444] For example, by combining the seventh embodiment described above with the second embodiment, a configuration can be achieved in which a plurality of pixels 100 (pixels 100 having a 1PD structure) are arranged in the row or column direction relative to an elliptical on-chip lens 111E in the row or column direction, and protrusions 114P can be formed in the plurality of pixels 100 by the inter-pixel light shielding portion 114.

[0445] Furthermore, for example, by combining the seventh embodiment described above with the third embodiment, a configuration can be achieved in which a plurality of pixels 100 (pixels 100 having a 1PD structure) are arranged in the row or column direction relative to an elliptical on-chip lens 111E in the row or column direction, and in the plurality of pixels 100, protrusions 115P are formed by the inter-pixel isolation portions 115, as well as protrusions 114P are formed by the inter-pixel light shielding portions 114.

[0446] For example, by combining the above-described eighth embodiment with the second embodiment, a configuration can be achieved in which two rows and two columns of pixels 100 (pixels 100 having a 1PD structure) are arranged for one on-chip lens 111, and protrusions 114P can be formed in the two rows and two columns of pixels 100 by the inter-pixel light shielding portions 114.

[0447] Furthermore, for example, by combining the eighth embodiment described above with the third embodiment, a configuration can be achieved in which two rows and two columns of pixels 100 (pixels 100 having a 1PD structure) are arranged relative to one on-chip lens 111, and in the two rows and two columns of pixels 100, protrusions 115P are formed by the inter-pixel isolation portions 115, as well as protrusions 114P are formed by the inter-pixel light shielding portions 114.

[0448] Furthermore, for example, by combining any of the tenth to thirteenth embodiments with any of the first to ninth embodiments described above, for example, in pixel 200 (pixel 300, pixel 400, or pixel 500), protrusion 215P (protrusion 315P, protrusion 415P, or protrusion 515P) may be formed by inter-pixel separation portion 215 (inter-pixel separation portion 315, inter-pixel separation portion 415, or inter-pixel separation portion 515).

[0449] In this case, for example, in pixel 200 (pixel 300, pixel 400, or pixel 500), protrusion 214P (protrusion 314P, protrusion 414P, or protrusion 514P) may be formed by inter-pixel light shielding portion 214 (inter-pixel light shielding portion 314, inter-pixel light shielding portion 414, or inter-pixel light shielding portion 514).

[0450] In the above description, the pixel 100 has been described as having a structure (2PD structure) in which left and right photoelectric conversion elements 113A, 113B are provided for one on-chip lens 111, but the left and right photoelectric conversion elements 113A, 113B may be regarded as a left pixel 100A and a right pixel 100B. In other words, the pixel 100 can be said to be a pixel unit composed of the left pixel 100A having the photoelectric conversion element 113A and the right pixel 100B having the photoelectric conversion element 113B.

[0451] Similarly, pixel 200 (pixel 300, pixel 400, or pixel 500) can be considered to be a pixel portion composed of a left pixel 200A (left pixel 300A, left pixel 400A, or left pixel 500A) having a photoelectric conversion element 213A (photoelectric conversion element 313A, photoelectric conversion element 413A, or photoelectric conversion element 513A), and a right pixel 200B (right pixel 300B, right pixel 400B, or right pixel 500B) having a photoelectric conversion element 213B (photoelectric conversion element 313B, photoelectric conversion element 413B, or photoelectric conversion element 513B).

[0452] In the above description, a case has been described in which photodiodes (PD) are used as the photoelectric conversion elements 113A and 113B of the pixel 100, but other members (elements) such as a photoelectric conversion film may be used. Also, the on-chip lens 111 is a lens on a pixel that performs focus detection, and can be said to be a microlens. The same applies to the pixel 200, pixel 300, pixel 400, or pixel 500.

[0453] In the above description, the inter-pixel light shielding portion 114 and the inter-pixel separating portion 115 are formed in a square lattice pattern for the pixel 100, but the shape is not limited to a square lattice pattern and may be other shapes, such as a rectangle including a rectangle. Furthermore, the pixel 100 is not limited to being formed in a square unit and may be formed in other units. The same applies to the pixel 200, pixel 300, pixel 400, or pixel 500.

[0454] In the above description, R pixels, G pixels, and B pixels are shown as the pixels 100 (pixels 200, 300, 400, or 500) two-dimensionally arranged in the pixel array section 11 (FIG. 1). However, pixels other than RGB pixels, such as W pixels corresponding to white (W) and IR pixels corresponding to infrared (IR), may also be included. The W pixels are pixels that transmit light in all wavelength ranges and obtain charges corresponding to the light. The IR pixels are pixels that transmit infrared (IR) light and have sensitivity to the wavelength band of infrared light.

[0455] (Another Example of a Solid-State Imaging Device) In the above-described embodiment, the present technology is applied to a CMOS image sensor in which pixels are arranged two-dimensionally, but the present technology is not limited to the application to a CMOS image sensor. In other words, the present technology is applicable to all solid-state imaging devices of the XY address type in which pixels are arranged two-dimensionally, such as a CCD (Charge Coupled Device) image sensor.

[0456] Furthermore, the present technology is not limited to application to a solid-state imaging device that detects the distribution of the amount of incident visible light and captures it as an image, but can be applied to all solid-state imaging devices that capture the distribution of the amount of incident infrared rays, X-rays, particles, etc., as an image. In addition, the above-mentioned embodiment has been described mainly with respect to the pixel 100 having a 2PD structure in which two photoelectric conversion elements 113 are formed for one on-chip lens 111, but the present technology can be similarly applied to the pixel 100 in which a plurality of photoelectric conversion elements 113 are formed for one on-chip lens 111.

[0457] <6. Configuration of electronic devices>

[0458] FIG. 63 is a block diagram showing a configuration example of an electronic device having a solid-state imaging device to which the present technology is applied.

[0459] The electronic device 1000 is, for example, an imaging device such as a digital still camera or a video camera, or a mobile terminal device such as a smartphone or a tablet terminal.

[0460] The electronic device 1000 is composed of a solid-state imaging device 1001, a DSP circuit 1002, a frame memory 1003, a display unit 1004, a recording unit 1005, an operation unit 1006, and a power supply unit 1007. In the electronic device 1000, the DSP circuit 1002, the frame memory 1003, the display unit 1004, the recording unit 1005, the operation unit 1006, and the power supply unit 1007 are connected to each other via a bus line 1008.

[0461] The solid-state imaging device 1001 corresponds to the above-mentioned CMOS image sensor 10 (FIG. 1), and can employ the pixels 100 shown in the first to ninth embodiments as the pixels 100 arranged two-dimensionally in the pixel array section 11 (FIG. 1). This allows the electronic device 1000 to detect a phase difference based on a signal for phase difference detection obtained from the pixel 100 (image surface phase difference detection pixel) shown in the first to ninth embodiments, and perform control to adjust the focus on a focusing object.

[0462] Furthermore, the pixels 200, 300, 400, or 500 shown in the tenth to thirteenth embodiments may be arranged as pixels two-dimensionally arranged in the pixel array unit 11 (FIG. 1). Even in this case, the electronic device 1000 can detect a phase difference based on a phase difference detection signal obtained from the pixel 200, pixel 300, pixel 400, or pixel 500, and perform control to adjust the focus on an object to be focused.

[0463] Since pixel 100 has a structure (2PD structure) in which two photoelectric conversion elements 113A and 113B are provided for one on-chip lens 111, a pixel signal (A+B signal) generated by adding up the charges accumulated in photoelectric conversion elements 113A and 113B is used as a signal for image acquisition, and a pixel signal (A signal) obtained from the charges accumulated in photoelectric conversion element 113A and a pixel signal (B signal) obtained from the charges accumulated in photoelectric conversion element 113B can be read out independently and used as signals for phase difference detection.

[0464] In this way, the pixel 100 has a 2PD structure and can be used both as a pixel for image acquisition and as a pixel for phase difference detection (image surface phase difference detection pixel). Although detailed explanation is omitted, the pixels 200, 300, 400, and 500 also have a 2PD structure and can be used both as a pixel for image acquisition and as a pixel for phase difference detection.

[0465] The DSP circuit 1002 is a camera signal processing circuit that processes signals supplied from the solid-state imaging device 1001. The DSP circuit 1002 outputs image data obtained by processing the signals from the solid-state imaging device 1001. The frame memory 1003 temporarily holds the image data processed by the DSP circuit 1002 on a frame-by-frame basis.

[0466] The display unit 1004 is formed of a panel-type display device such as a liquid crystal panel or an organic EL (Electro Luminescence) panel, and displays moving images or still images captured by the solid-state imaging device 1001. The recording unit 1005 records image data of the moving images or still images captured by the solid-state imaging device 1001 in a recording medium such as a semiconductor memory or a hard disk.

[0467] In response to a user's operation, the operation unit 1006 outputs operation commands for various functions of the electronic device 1000. The power supply unit 1007 appropriately supplies various types of power to the DSP circuit 1002, the frame memory 1003, the display unit 1004, the recording unit 1005, and the operation unit 1006 as operating power sources to these power sources.

[0468] The electronic device 1000 is configured as described above. As described above, the present technology is applied to the solid-state imaging device 1001. Specifically, the CMOS image sensor 10 (FIG. 1) can be applied to the solid-state imaging device 1001. By applying the present technology to the solid-state imaging device 1001, a protrusion is formed by the inter-pixel light shielding portion 114 or the inter-pixel isolating portion 115 in an area of ​​the pixel 100 that has a low contribution to isolation, thereby making it possible to improve the accuracy of phase difference detection while suppressing deterioration of the captured image.

[0469] <7. Examples of use of solid-state imaging devices>

[0470] FIG. 64 is a diagram showing an example of use of a solid-state imaging device to which the present technology is applied.

[0471] The CMOS image sensor 10 (FIG. 1) can be used in various cases for sensing light such as visible light, infrared light, ultraviolet light, X-rays, etc., as described below. That is, as shown in FIG. 64, the CMOS image sensor 10 can be used not only in the field of appreciation for capturing images for appreciation, but also in devices used in the fields of transportation, home appliances, medicine and health care, security, beauty, sports, agriculture, etc.

[0472] Specifically, in the field of appreciation, the CMOS image sensor 10 can be used in devices for capturing images for appreciation purposes (e.g., electronic device 1000 in FIG. 63), such as digital cameras, smartphones, and mobile phones with camera functions.

[0473] In the field of transportation, the CMOS image sensor 10 can be used in devices used for transportation purposes, such as in-vehicle sensors that capture images of the front, rear, surroundings, and interior of a vehicle for safe driving such as automatic stopping and for recognition of the driver's condition, surveillance cameras that monitor moving vehicles and roads, and distance measuring sensors that measure distances between vehicles, etc.

[0474] In the field of home appliances, for example, the CMOS image sensor 10 can be used in devices provided for home appliances such as television receivers, refrigerators, and air conditioners to capture images of user gestures and operate the appliances in accordance with the gestures. Also, in the field of medicine and healthcare, for example, the CMOS image sensor 10 can be used in devices provided for medical and healthcare purposes such as endoscopes and devices for capturing images of blood vessels by receiving infrared light.

[0475] In the field of security, the CMOS image sensor 10 can be used in devices for security purposes, such as surveillance cameras for crime prevention, cameras for person authentication, etc. In the field of beauty, the CMOS image sensor 10 can be used in devices for beauty purposes, such as skin measuring devices for photographing the skin, and microscopes for photographing the scalp.

[0476] In the field of sports, the CMOS image sensor 10 can be used in devices for sports, such as action cameras and wearable cameras for sports applications, etc. In the field of agriculture, the CMOS image sensor 10 can be used in devices for agricultural purposes, such as cameras for monitoring the condition of fields and crops.

[0477] 8. Configuration Examples of Stacked Solid-State Imaging Devices to Which the Technology of the Present Disclosure Can Be Applied>

[0478] FIG. 65 is a diagram showing an outline of a configuration example of a stacked solid-state imaging device to which the technology according to the present disclosure can be applied.

[0479] A of Fig. 65 shows a schematic configuration example of a non-stacked solid-state imaging device. As shown in A of Fig. 65, a solid-state imaging device 23010 has one die (semiconductor substrate) 23011. This die 23011 is equipped with a pixel region 23012 in which pixels are arranged in an array, a control circuit 23013 that drives the pixels and performs various other controls, and a logic circuit 23014 that processes signals.

[0480] B and C of Fig. 65 show a schematic configuration example of a stacked type solid-state imaging device. As shown in B and C of Fig. 65, the solid-state imaging device 23020 is configured as one semiconductor chip by stacking two dies, a sensor die 23021 and a logic die 23024, and electrically connecting them.

[0481] In B of FIG. 65, a pixel region 23012 and a control circuit 23013 are mounted on a sensor die 23021, and a logic circuit 23014 including a signal processing circuit that performs signal processing is mounted on a logic die 23024.

[0482] In FIG. 65C, a pixel region 23012 is mounted on a sensor die 23021, and a control circuit 23013 and a logic circuit 23014 are mounted on a logic die 23024.

[0483] FIG. 66 is a cross-sectional view showing a first configuration example of a stacked solid-state imaging device 23020.

[0484] The sensor die 23021 is formed with a PD (photodiode), an FD (floating diffusion), a Tr (MOS FET), and a Tr that constitute a pixel that becomes a pixel region 23012, and a Tr that constitutes a control circuit 23013. Furthermore, the sensor die 23021 is formed with a wiring layer 23101 having multiple layers, three layers in this example, of wiring 23110. Note that the control circuit 23013 (Tr that constitutes the control circuit) can be formed in the logic die 23024, not in the sensor die 23021.

[0485] The logic die 23024 is formed with transistors that constitute the logic circuit 23014. Furthermore, the logic die 23024 is formed with a wiring layer 23161 having multiple layers, three layers in this example, of wiring 23170. Furthermore, the logic die 23024 is formed with a connection hole 23171 having an insulating film 23172 formed on its inner wall surface, and a connection conductor 23173 that is connected to the wiring 23170 and the like is embedded in the connection hole 23171.

[0486] The sensor die 23021 and the logic die 23024 are bonded together so that their wiring layers 23101 and 23161 face each other, thereby forming a stacked solid-state imaging device 23020 in which the sensor die 23021 and the logic die 23024 are stacked. A film 23191 such as a protective film is formed on the surface where the sensor die 23021 and the logic die 23024 are bonded together.

[0487] The sensor die 23021 is formed with a connection hole 23111 penetrating the sensor die 23021 from the rear side (the side where light is incident on the PD) (upper side) of the sensor die 23021 to the wiring 23170 of the top layer of the logic die 23024. Furthermore, the sensor die 23021 is formed with a connection hole 23121 adjacent to the connection hole 23111, the connection hole 23121 reaching the wiring 23110 of the first layer from the rear side of the sensor die 23021. An insulating film 23112 is formed on the inner wall surface of the connection hole 23111, and an insulating film 23122 is formed on the inner wall surface of the connection hole 23121. Then, connection conductors 23113 and 23123 are embedded in the connection holes 23111 and 23121, respectively. The connection conductor 23113 and the connection conductor 23123 are electrically connected on the back side of the sensor die 23021, thereby electrically connecting the sensor die 23021 and the logic die 23024 via the wiring layer 23101, the connection hole 23121, the connection hole 23111, and the wiring layer 23161.

[0488] FIG. 67 is a cross-sectional view showing a second configuration example of the stacked solid-state imaging device 23020. As shown in FIG.

[0489] In a second configuration example of the solid-state imaging device 23020, a single connection hole 23211 formed in the sensor die 23021 electrically connects the sensor die 23021 (the wiring layer 23101 (the wiring 23110)) and the logic die 23024 (the wiring layer 23161 (the wiring 23170)).

[0490] 67, the connection hole 23211 is formed so as to penetrate the sensor die 23021 from the back surface side of the sensor die 23021, reach the uppermost wiring 23170 of the logic die 23024, and reach the uppermost wiring 23110 of the sensor die 23021. An insulating film 23212 is formed on the inner wall surface of the connection hole 23211, and a connection conductor 23213 is embedded in the connection hole 23211. In the above-mentioned FIG. 66, the sensor die 23021 and the logic die 23024 are electrically connected by two connection holes 23111 and 23121, but in FIG. 67, the sensor die 23021 and the logic die 23024 are electrically connected by one connection hole 23211.

[0491] FIG. 68 is a cross-sectional view showing a third configuration example of the stacked solid-state imaging device 23020.

[0492] The solid-state imaging device 23020 in Figure 68 differs from the case of Figure 66 in that a film 23191 such as a protective film is not formed on the surface where the sensor die 23021 and the logic die 23024 are bonded to each other, in that a film 23191 such as a protective film is not formed on the surface where the sensor die 23021 and the logic die 23024 are bonded to each other.

[0493] The solid-state imaging device 23020 in FIG. 68 is constructed by overlapping a sensor die 23021 and a logic die 23024 so that the wirings 23110 and 23170 are in direct contact with each other, and heating them while applying a required load, thereby directly bonding the wirings 23110 and 23170.

[0494] FIG. 69 is a cross-sectional view showing another configuration example of a stacked solid-state imaging device to which the technology according to the present disclosure can be applied.

[0495] In FIG. 69, a solid-state imaging device 23401 has a three-layer stacked structure in which three dies, a sensor die 23411, a logic die 23412, and a memory die 23413, are stacked.

[0496] The memory die 23413 has, for example, a memory circuit that stores data temporarily required for signal processing performed in the logic die 23412.

[0497] In FIG. 69, the logic die 23412 and the memory die 23413 are stacked in that order below the sensor die 23411, but the logic die 23412 and the memory die 23413 can be stacked below the sensor die 23411 in the reverse order, i.e., the memory die 23413 and the logic die 23412.

[0498] In addition, in FIG. 69, the sensor die 23411 has PDs which are photoelectric conversion units of pixels and source / drain regions of pixel Tr formed thereon.

[0499] A gate electrode is formed around the PD with a gate insulating film interposed therebetween, and pixels Tr23421 and Tr23422 are formed by the gate electrode and a pair of source / drain regions.

[0500] The pixel Tr2 3421 adjacent to the PD is a transfer Tr, and one of the pair of source / drain regions constituting the pixel Tr2 3421 is an FD.

[0501] An interlayer insulating film is formed on the sensor die 23411, and a connection hole is formed in the interlayer insulating film. A connection conductor 23431 connected to the pixel Tr23421 and the pixel Tr23422 is formed in the connection hole.

[0502] Furthermore, the sensor die 23411 is formed with a wiring layer 23433 having multiple layers of wiring 23432 connected to each of the connection conductors 23431 .

[0503] Furthermore, an aluminum pad 23434 serving as an electrode for external connection is formed on the bottom layer of the wiring layer 23433 of the sensor die 23411. That is, on the sensor die 23411, the aluminum pad 23434 is formed at a position closer to the bonding surface 23440 with the logic die 23412 than the wiring 23432. The aluminum pad 23434 is used as one end of a wiring related to input / output of a signal to / from the outside.

[0504] Furthermore, a contact 23441 used for electrical connection with the logic die 23412 is formed on the sensor die 23411. The contact 23441 is connected to a contact 23451 of the logic die 23412 and is also connected to an aluminum pad 23442 of the sensor die 23411.

[0505] The sensor die 23411 has a pad hole 23443 formed therein so as to reach the aluminum pad 23442 from the rear surface side (upper side) of the sensor die 23411 .

[0506] The technology according to the present disclosure can be applied to the above-described solid-state imaging device.

[0507] <9. Application examples for mobile devices>

[0508] 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 moving body such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, a robot, etc.

[0509] FIG. 70 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a moving object control system to which the technology of the present disclosure can be applied.

[0510] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 70, 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, as functional configurations of the integrated control unit 12050, a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (Interface) 12053 are illustrated.

[0511] 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.

[0512] The body system control unit 12020 controls the operation of various devices mounted on 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 head lamps, back lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves or signals of various switches transmitted from a portable device that replaces a key may be input to the body system control unit 12020. The body system control unit 12020 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, and the like of the vehicle.

[0513] 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 an image outside the vehicle and receives the captured image. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for a person, a car, an obstacle, a sign, or characters on a road surface, based on the received image.

[0514] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according 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.

[0515] 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.

[0516] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the outside-of-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output a control command 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.

[0517] 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 the driver's operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle acquired by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0518] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12030 based on the information outside the vehicle acquired by the outside-vehicle 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-vehicle information detection unit 12030, and perform cooperative control for the purpose of preventing glare, such as switching from high beams to low beams.

[0519] The audio / video output unit 12052 transmits at least one output signal of audio and video to an output device capable of visually or audibly notifying information to passengers in the vehicle or the outside of the vehicle. In the example of Fig. 70, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as the output device. The display unit 12062 may include at least one of an on-board display and a head-up display, for example.

[0520] FIG. 71 is a diagram showing an example of the installation position of the imaging unit 12031.

[0521] In FIG. 71, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0522] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided at positions such as the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield in the vehicle interior of the vehicle 12100. The imaging unit 12101 provided at the front nose and the imaging unit 12105 provided at the upper part of the windshield in the vehicle interior mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided at the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided at the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided at the upper part of the windshield in the vehicle interior is mainly used to detect a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

[0523] 71 shows an example of the imaging ranges of the imaging units 12101 to 12104. An 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 an imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, an overhead image of the vehicle 12100 viewed from above is obtained by superimposing the image data captured by the imaging units 12101 to 12104.

[0524] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera made up of a plurality of imaging elements, or may be an imaging element having pixels for detecting a phase difference.

[0525] For example, the microcomputer 12051 can extract, as a preceding vehicle, a three-dimensional object that is the closest three-dimensional object on the travel path of the vehicle 12100 and travels at a predetermined speed (for example, 0 km / h or more) in approximately the same direction as the vehicle 12100, by calculating the distance to each three-dimensional object in the imaging ranges 12111 to 12114 and the change over time of this distance (relative speed with respect to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104. Furthermore, the microcomputer 12051 can set a vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including follow-up stop control) and automatic acceleration control (including follow-up start control). In this way, cooperative control can be performed for the purpose of automatic driving that travels autonomously without relying on the driver's operation.

[0526] For example, the microcomputer 12051 classifies and extracts three-dimensional object data on 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. Then, the microcomputer 12051 determines a collision risk indicating 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.

[0527] At least one of the imaging 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 or not a pedestrian is present in the captured images of the imaging units 12101 to 12104. The recognition of such a pedestrian is performed, for example, by a procedure of extracting feature points in the captured images of the imaging units 12101 to 12104 as infrared cameras, and a procedure of performing pattern matching processing on a series of feature points that indicate the contour of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the captured images of the imaging units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

[0528] An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 12031 among the configurations described above. Specifically, the CMOS image sensor 10 in FIG. 1 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 improve the accuracy of phase difference detection while suppressing deterioration of the captured image, so that, for example, it is possible to obtain a captured image of higher quality and more accurately recognize obstacles such as pedestrians.

[0529] The embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present technology.

[0530] The present technology can also be configured as follows.

[0531] (1) a pixel array unit in which a plurality of pixels, including a pixel in which a plurality of photoelectric conversion elements are formed for one on-chip lens, are two-dimensionally arranged; At least one of the inter-pixel isolation portion and the inter-pixel light shielding portion formed between the pixels has a part that protrudes toward the center of the pixel to form a protrusion. Solid-state imaging device. (2) The pixel is a square unit pixel, The protrusion is formed toward the center of the pixel of the square unit. The solid-state imaging device according to (1) above. (3) the inter-pixel isolation portion physically isolates adjacent pixels from each other by a material filled in a groove portion that is dug in a square lattice shape in a semiconductor layer in which the plurality of photoelectric conversion elements are formed, A part of the inter-pixel separation portion protrudes in a protruding shape toward the center of the square unit pixel to form the protrusion. The solid-state imaging device according to (2) above. (4) the inter-pixel light shielding portion shields light between adjacent pixels by a material formed in a square lattice shape in a region between the on-chip lens and a semiconductor layer in which the plurality of photoelectric conversion elements are formed, A part of the inter-pixel light shielding portion protrudes in a protruding shape toward the center of the pixel of the square unit to form the protruding portion. The solid-state imaging device according to (2) above. (5) the inter-pixel isolation portion physically isolates adjacent pixels from each other by a material filled in a groove portion that is dug in a square lattice shape in a semiconductor layer in which the plurality of photoelectric conversion elements are formed, the inter-pixel light shielding portion shields light between adjacent pixels by a material formed in a square lattice shape in a region between the on-chip lens and a semiconductor layer in which the plurality of photoelectric conversion elements are formed, A part of each of the inter-pixel isolation portion and the inter-pixel light shielding portion protrudes in a protruding shape toward the center of the pixel of the square unit to form the protruding portion. The solid-state imaging device according to (2) above. (6) the pixels of the square unit are configured as R pixels, G pixels, or B pixels according to a red (R), green (G), or blue (B) color filter disposed directly under the on-chip lens; The protrusion portion is formed on at least one of the R pixels, the G pixels, and the B pixels among the plurality of pixels arranged in the pixel array portion. The solid-state imaging device according to any one of (1) to (5). (7) The protrusion is formed only on the R pixel, only on the G pixel, or only on the B pixel. The solid-state imaging device according to (6) above. (8) The protrusion is formed in all of the R pixels, the G pixels, and the B pixels. The solid-state imaging device according to (6) above. (9) The protrusion is formed on two of the R pixel, the G pixel, and the B pixel that are combined. The solid-state imaging device according to (6) above. (10) The length of the protruding portion of the protrusion is different for each pixel including the R pixel, the G pixel, and the B pixel. The solid-state imaging device according to any one of (6) to (9). (11) The length of the protruding portion of the protrusion is determined according to the diameter of the light spot focused by the on-chip lens. The solid-state imaging device according to any one of (2) to (10) above. (12) The length of the protruding portion of the protrusion corresponds to 1 / 7 to 1 / 4 of the length of one side of the pitch of the on-chip lens. The solid-state imaging device according to (11) above. (13) The cross section of the protrusion with respect to the light incident surface has a different depth for each protruding portion. The solid-state imaging device according to any one of (2) to (12). (14) The grooves are dug from a first surface, which is a surface on the light incident side, or from a second surface, which is a surface on the opposite side to the light incident side. The solid-state imaging device according to (3) or (5). (15) In the square unit pixel, the plurality of photoelectric conversion elements formed in the semiconductor layer are separated by impurities. The solid-state imaging device according to any one of (2) to (14). (16) The outputs of the plurality of photoelectric conversion elements are used for phase difference detection. The solid-state imaging device according to any one of (2) to (15) above. (17) A pixel array unit is provided in which a plurality of pixels, including a pixel having one photoelectric conversion element, are arranged two-dimensionally, the pixel array unit includes a plurality of pixels arranged for one on-chip lens, At least one of the inter-pixel isolation portion and the inter-pixel light shielding portion formed between the pixels constituting the plurality of pixels has a part protruding in a protruding shape toward the center of the plurality of pixels to form a protruding portion. Solid-state imaging device. (18) the on-chip lens has an elliptical shape spanning two consecutive pixels in a row or column direction, At least one of the inter-pixel separating portion and the inter-pixel light shielding portion has a portion protruding between the two pixels to form the protrusion. The solid-state imaging device according to (17) above. (19) The on-chip lens has a circular shape spanning four pixels in two rows and two columns, At least one of the inter-pixel isolation portion and the inter-pixel light shielding portion has a portion protruding toward the center of the four pixels to form the protrusion portion. The solid-state imaging device according to (17) above. (20) a pixel array section in which a plurality of pixels, including a pixel in which a plurality of photoelectric conversion elements are formed for one on-chip lens, are two-dimensionally arranged; At least one of the inter-pixel isolation portion and the inter-pixel light shielding portion formed between the pixels has a part that protrudes toward the center of the pixel to form a protrusion. Solid-state imaging device Equipped with electronic equipment. (twenty one) a pixel array unit in which a plurality of pixels, including a pixel in which a plurality of photoelectric conversion elements are formed for one on-chip lens, are two-dimensionally arranged; At or near an interface on a light incident surface side of the semiconductor layer in which the plurality of photoelectric conversion elements are formed, a first region between the plurality of photoelectric conversion elements and a second region excluding the first region have different amounts of fixed charge. Solid-state imaging device. (twenty two) The amount of fixed charge in the first region is greater than the amount of fixed charge in the second region. The solid-state imaging device according to (21) above. (twenty three) an insulating layer formed on the semiconductor layer includes, together with an oxide film, a first film in a portion corresponding to the first region and a second film in a portion corresponding to the second region; The first film and the second film are formed of different high dielectric constant films. The solid-state imaging device according to (21) or (22). (twenty four) At least one of the first film and the second film is a laminate of two or more different high dielectric constant films. The solid-state imaging device according to (23) above. (twenty five) The first film has a larger number of layers than the second film. The solid-state imaging device according to (24) above. (26) the insulating layer formed on the semiconductor layer includes an oxide film and a high dielectric constant film; In the insulating layer, a portion corresponding to the first region and a portion corresponding to the second region have different thicknesses of the oxide film. The solid-state imaging device according to (21) or (22). (27) The pixels are configured as pixels of a color corresponding to a color filter disposed directly under the on-chip lens. The solid-state imaging device according to any one of (21) to (26). (28) A first photoelectric conversion element formed in a pixel corresponding to a first color and a second photoelectric conversion element formed in a pixel corresponding to a second color different from the first color are separated by an impurity. The solid-state imaging device according to (27) above. (29) A first photoelectric conversion element formed in a pixel corresponding to a first color and a second photoelectric conversion element formed in a pixel corresponding to a second color different from the first color are separated by an inter-pixel separation portion including an oxide film or a metal. The solid-state imaging device according to (27) above. (30) A transparent electrode is formed between the plurality of photoelectric conversion elements formed in pixels corresponding to a specific color. The solid-state imaging device according to (27) above. (31) The pixels include an R pixel, a G pixel, and a B pixel. The solid-state imaging device according to any one of (27) to (30). (32) a pixel array unit in which a plurality of pixels, including a pixel in which a plurality of photoelectric conversion elements are formed for one on-chip lens, are two-dimensionally arranged; At or near an interface on a light incident surface side of the semiconductor layer in which the plurality of photoelectric conversion elements are formed, a first region between the plurality of photoelectric conversion elements and a second region excluding the first region have different amounts of fixed charge. Solid-state imaging device Equipped with electronic equipment. (33) a pixel array unit in which a plurality of pixels, including a pixel in which a plurality of photoelectric conversion elements are formed for one on-chip lens, are two-dimensionally arranged; forming a first isolation region in which a first embedded element containing a low refractive index material is embedded between the plurality of photoelectric conversion elements formed in a pixel corresponding to a specific color; A second isolation region in which a second embedded element containing a metal is embedded is formed between a first photoelectric conversion element formed in a pixel corresponding to a first color and a second photoelectric conversion element formed in a pixel corresponding to a second color different from the first color. Solid-state imaging device. (34) The cross section of the first separation region has a tapered shape that widens toward the light incident surface. The solid-state imaging device according to (33) above. (35) The cross section of the first isolation region is triangular. The solid-state imaging device according to (34) above. (36) a cross section of the first isolation region in which the first embedded element disappears at a predetermined depth from a light incident surface, The region below the first isolation region is isolated by an impurity. The solid-state imaging device according to (35) above. (37) The cross section of the first separation region is triangular from the light incident surface to a predetermined depth, and is rectangular beyond the predetermined depth. The solid-state imaging device according to (34) above. (38) The cross section of the first separation region is trapezoidal and tapered from the surface on the light incident side to the surface on the opposite side to the light incident side. The solid-state imaging device according to (34) above. (39) The plane of the first separation region has a rectangular shape when viewed from the light incident side. The solid-state imaging device according to any one of (33) to (38). (40) The plane of the first separation region is shaped like a rhombus when viewed from the light incident side. The solid-state imaging device according to any one of (33) to (38). (41) the second embedded element further comprises a low refractive index material; In the cross section of the second separation region, the metal is embedded to a predetermined depth from the surface on the light incident side, and the low refractive index material is embedded to a predetermined depth from the surface on the opposite side to the light incident side. The solid-state imaging device according to any one of (33) to (40). (42) A fixed charge film is formed on a side wall of the second isolation region. The solid-state imaging device according to any one of (33) to (41). (43) The pixels are configured as pixels of a color corresponding to a color filter disposed directly under the on-chip lens. The solid-state imaging device according to any one of (33) to (42). (44) The pixels include an R pixel, a G pixel, and a B pixel. The solid-state imaging device according to (43) above. (45) a pixel array unit in which a plurality of pixels, including a pixel in which a plurality of photoelectric conversion elements are formed for one on-chip lens, are two-dimensionally arranged; forming a first isolation region in which a first embedded element containing a low refractive index material is embedded between the plurality of photoelectric conversion elements formed in a pixel corresponding to a specific color; A second isolation region in which a second embedded element containing a metal is embedded is formed between a first photoelectric conversion element formed in a pixel corresponding to a first color and a second photoelectric conversion element formed in a pixel corresponding to a second color different from the first color. Solid-state imaging device Equipped with electronic equipment. (46) a pixel array unit in which a plurality of pixels, including a pixel in which a plurality of photoelectric conversion elements are formed for one on-chip lens, are two-dimensionally arranged; The on-chip lens is formed of a plurality of types of materials. Solid-state imaging device. (47) The on-chip lens is formed of two types of materials with different refractive indices. The solid-state imaging device according to (46) above. (48) the on-chip lens is composed of a first member having a first refractive index and a second member having a second refractive index lower than the first refractive index; the first member includes a curved surface onto which light is incident and a portion corresponding to the V-shaped portion of the second member, The second member includes a surface opposite to the curved surface into which light is incident and a V-shaped portion. The solid-state imaging device according to (47) above. (49) The on-chip lens is made of three materials with different refractive indices. The solid-state imaging device according to (46) above. (50) the on-chip lens is composed of a first member having a first refractive index, a second member having a second refractive index, and a third member having a third refractive index; the plurality of photoelectric conversion elements formed in the pixel are physically separated by an inter-element separation portion; the first member includes a curved surface onto which light is incident and a portion corresponding to the V-shaped portion of the second member, the second member includes a surface opposite to the curved surface into which light is incident and a V-shaped portion; The third member is formed in a region corresponding to the element isolation portion. The solid-state imaging device according to (49) above. (51) The pixels are configured as pixels corresponding to specific colors, The height of the on-chip lens at the pixel varies for each specific color. The solid-state imaging device according to (49) above. (52) The pixels include an R pixel, a G pixel, and a B pixel, The height of the on-chip lens decreases in the order of the R pixel, the G pixel, and the B pixel. The solid-state imaging device according to (51) above. (53) The pixels are configured as pixels corresponding to specific colors, The radius of curvature of the on-chip lens in the pixel varies for each specific color. The solid-state imaging device according to (49) above. (54) The pixels include an R pixel, a G pixel, and a B pixel, The radius of curvature of the on-chip lens decreases in the order of the R pixel, the G pixel, and the B pixel. The solid-state imaging device according to (53) above. (55) The pixels are configured as pixels of a color corresponding to a color filter disposed directly under the on-chip lens. The solid-state imaging device according to any one of (46) to (54). (56) A control member for controlling the incidence angle dependency of light is formed on the member forming the on-chip lens. The solid-state imaging device according to (46) above. (57) the on-chip lens is composed of a first member having a first refractive index and a second member having a second refractive index lower than the first refractive index; the first member includes a curved surface onto which light is incident and a portion corresponding to the V-shaped portion of the second member, the second member includes a surface opposite to the curved surface into which light is incident and a V-shaped portion; The control member is formed between the first member and the second member. The solid-state imaging device according to (56) above. (58) The control member is a photonic crystal. The solid-state imaging device according to (56) or (57) above. (59) The pixels are configured as pixels of a color corresponding to the spectrum determined by the control member. The solid-state imaging device according to any one of (56) to (58). (60) The pixels include an R pixel, a G pixel, and a B pixel. The solid-state imaging device according to (59) above. (61) a pixel array unit in which a plurality of pixels, including a pixel in which a plurality of photoelectric conversion elements are formed for one on-chip lens, are two-dimensionally arranged; The on-chip lens is formed of a plurality of types of materials. Solid-state imaging device Equipped with electronic equipment. (62) a pixel array unit in which a plurality of pixels, including a pixel in which a plurality of photoelectric conversion elements are formed for one on-chip lens, are two-dimensionally arranged; A first vertical transistor is formed between the plurality of photoelectric conversion elements formed in a pixel corresponding to a specific color, from the surface opposite to the light incident side. Solid-state imaging device. (63) A voltage is applied to the first vertical transistor to generate a blooming path between the plurality of photoelectric conversion elements. The solid-state imaging device according to (62) above. (64) A second vertical transistor is formed between a first photoelectric conversion element formed in a pixel corresponding to a first color and a second photoelectric conversion element formed in a pixel corresponding to a second color different from the first color, from a surface opposite to the light incident side. The solid-state imaging device according to (62) or (63). (65) A voltage is applied to the second vertical transistor to generate a charge. The solid-state imaging device according to (64) above. (66) An inter-pixel separation portion is formed between the first photoelectric conversion element and the second photoelectric conversion element from the light incident surface. The solid-state imaging device according to (64) or (65) above. (67) The pixels are configured as pixels of a color corresponding to a color filter disposed directly under the on-chip lens. The solid-state imaging device according to any one of (62) to (66). (68) The pixels include an R pixel, a G pixel, and a B pixel. The solid-state imaging device according to (67) above. (69) a pixel array unit in which a plurality of pixels, including a pixel in which a plurality of photoelectric conversion elements are formed for one on-chip lens, are two-dimensionally arranged; A first vertical transistor is formed between the plurality of photoelectric conversion elements formed in a pixel corresponding to a specific color from a surface opposite to the light incident side. Solid-state imaging device Equipped with electronic equipment. [Explanation of symbols]

[0532] 10 CMOS image sensor, 11 pixel array section, 100,100-ij pixel, 111,111E on-chip lens, 112 color filter, 113A,113B photoelectric conversion element, 114 inter-pixel light shielding section, 114P protrusion, 115 inter-pixel isolation section, 115P protrusion, 151A,151B transfer gate section, 200 pixel, 210 silicon layer, 211 on-chip lens, 212 color filter, 213A,213B photoelectric conversion element, 214 inter-pixel light shielding section, 215 inter-pixel isolation section, 220 interface layer, 221 central region, 222 left and right regions, 230 insulating layer, 231 oxide film, 232A,232B,232C,232D,232E High-k film, 233 Oxide film, 241 Transparent electrode, 300 Pixel, 310 Silicon layer, 311 On-chip lens, 312 Color filter, 313A,313B Photoelectric conversion element, 314 Light shielding part between pixels, 315 Inter-pixel separation part, 321 Center part between same colors, 322 Center part between different colors, 331 Low refractive index area, 341 Low refractive index area, 400 Pixel, 410 Silicon layer, 411,411E On-chip lens, 411A,411B,411C Member, 412 Color filter, 413A,413B Photoelectric conversion element, 414 Light shielding part between pixels, 415 Inter-pixel separation section, 416 Inter-element separation section, 421, 421R, 421G, 421B Control member, 500 Pixel, 510 Silicon layer, 511 On-chip lens, 512 Color filter, 513A, 513B Photoelectric conversion element, 514 Inter-pixel light shielding section, 515 Inter-pixel separation section, 521 Center section between same colors, 522 Center section between different colors, 531 Vertical transistor, 532 Vertical transistor, 1000 Electronic device, 1001 Solid-state imaging device, 12031 Imaging section

Claims

1. a pixel array unit in which a plurality of pixels including a pixel in which a first photoelectric conversion element and a second photoelectric conversion element are formed for one on-chip lens are two-dimensionally arranged; a part of the inter-pixel isolation portion of the inter-pixel light shielding portion formed between the pixels protrudes toward a center of the pixel to form a first protrusion and a second protrusion, the inter-pixel isolation portion physically isolates adjacent pixels from each other by a first substance embedded in a groove formed in a semiconductor layer in which the first photoelectric conversion element and the second photoelectric conversion element are formed; the inter-pixel light shielding portion shields light between adjacent pixels by a second material formed in a region between the on-chip lens and the semiconductor layer, The first photoelectric conversion element and the second photoelectric conversion element are formed as a first conductivity type region, the first protrusion and the second protrusion are formed in a second conductivity type region between the first photoelectric conversion element and the second photoelectric conversion element, The first protrusion and the second protrusion are not in contact with each other and are capable of exchanging electric charges stored in the first photoelectric conversion element and the second photoelectric conversion element. Solid-state imaging device.

2. The pixel is a square unit pixel, The first protrusion and the second protrusion are formed toward the center of the pixel of the square unit. The solid-state imaging device according to claim 1 .

3. the inter-pixel isolation portion and the inter-pixel light shielding portion are formed corresponding to the pixels of the square unit, The first protrusion and the second protrusion are formed by protruding parts of opposing sides of the inter-pixel separator. The solid-state imaging device according to claim 2 .

4. The first protrusion and the second protrusion are formed of the same material as the inter-pixel separation portion or a different material. The solid-state imaging device according to claim 1 .

5. the pixel of the square unit is configured as an R pixel, a G pixel, or a B pixel according to a red (R), green (G), or blue (B) color filter disposed directly under the on-chip lens; The first protrusion and the second protrusion are formed for at least one of the R pixel, the G pixel, and the B pixel among a plurality of pixels arranged in the pixel array unit. The solid-state imaging device according to claim 2 .

6. The first protrusion and the second protrusion are formed only in the R pixel, only in the G pixel, or only in the B pixel. The solid-state imaging device according to claim 5 .

7. The first protrusion and the second protrusion are formed in all of the R pixel, the G pixel, and the B pixel. The solid-state imaging device according to claim 5 .

8. The first protrusion and the second protrusion are formed in two pixels that are combined among the R pixel, the G pixel, and the B pixel. The solid-state imaging device according to claim 5 .

9. The lengths of the protruding portions of the first protrusion and the second protrusion are different for each pixel including the R pixel, the G pixel, and the B pixel. The solid-state imaging device according to claim 5 .

10. The length of the protruding portion of the first protrusion and the second protrusion is determined according to the diameter of the light spot focused by the on-chip lens. The solid-state imaging device according to claim 2 .

11. The length of the protruding portion of the first protrusion and the second protrusion corresponds to 1 / 7 to 1 / 4 of the length of one side of the pitch of the on-chip lens. The solid-state imaging device according to claim 10.

12. The cross sections of the first protrusion and the second protrusion with respect to the light incident surface have different depths for each protruding portion. The solid-state imaging device according to claim 2 .

13. The grooves are dug from a first surface, which is a surface on the light incident side, or from a second surface, which is a surface on the opposite side to the light incident side. The solid-state imaging device according to claim 1 .

14. In the square unit pixel, the first photoelectric conversion element and the second photoelectric conversion element formed in the semiconductor layer are separated by an impurity. The solid-state imaging device according to claim 2 .

15. The outputs of the first photoelectric conversion element and the second photoelectric conversion element are used for phase difference detection. The solid-state imaging device according to claim 2 .

16. the first conductivity type is N-type, The second conductivity type is P type. The solid-state imaging device according to claim 1 .

17. a pixel array section in which a plurality of pixels including a pixel in which a first photoelectric conversion element and a second photoelectric conversion element are formed for one on-chip lens are two-dimensionally arranged; a part of the inter-pixel isolation portion of the inter-pixel light shielding portion formed between the pixels protrudes toward a center of the pixel to form a first protrusion and a second protrusion, the inter-pixel isolation portion physically isolates adjacent pixels from each other by a first substance embedded in a groove formed in a semiconductor layer in which the first photoelectric conversion element and the second photoelectric conversion element are formed; the inter-pixel light shielding portion shields light between adjacent pixels by a second material formed in a region between the on-chip lens and the semiconductor layer, The first photoelectric conversion element and the second photoelectric conversion element are formed as a first conductivity type region, the first protrusion and the second protrusion are formed in a second conductivity type region between the first photoelectric conversion element and the second photoelectric conversion element, The first protrusion and the second protrusion are not in contact with each other and are capable of exchanging electric charges stored in the first photoelectric conversion element and the second photoelectric conversion element. Solid-state imaging device Equipped with electronic equipment.

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