Light detection device and electronic device

Abstract

The present disclosure relates to a light detection device capable of improving the quantum efficiency of photoelectric conversion, and an electronic device. Provided is a light detection device comprising a pixel array unit in which a plurality of pixels including a pixel in which a plurality of photoelectric conversion units are formed with respect to one microlens are disposed in a two-dimensional array, wherein in the pixel, a first member constituting a waveguide which guides, to the center of the pixel, light focused by the microlens is disposed so as to avoid an in-pixel separation unit which is the light incident surface-side upper part of a semiconductor substrate having formed thereon the plurality of photoelectric conversion units in a cross-sectional view and which physically separates the plurality of photoelectric conversion units in a plan view.

Description

Photodetection device and electronic apparatus

[0001] The present disclosure relates to a photodetection device and an electronic apparatus, and particularly relates to a photodetection device and an electronic apparatus that can improve the quantum efficiency of photoelectric conversion.

[0002] As one autofocus method, a so-called image plane phase difference method is known, which performs phase difference type focus detection using pixels for phase difference detection. As the pixel for phase difference detection, a pixel in which a plurality of photoelectric conversion units are formed for one microlens can be used (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-open No.2013-211413

[0004] In a pixel for phase difference detection, when a configuration in which a plurality of photoelectric conversion units are formed for one microlens is employed, light is absorbed by the separation section that separates the photoelectric conversion units in the pixel, which may cause a reduction in the quantum efficiency of photoelectric conversion. Therefore, when a pixel for phase difference detection is used, it has been required to improve the quantum efficiency of photoelectric conversion.

[0005] The present disclosure has been made in view of such circumstances, and is intended to make it possible to improve the quantum efficiency of photoelectric conversion.

[0006] A photodetection device according to one aspect of the present disclosure includes a pixel array unit in which a plurality of pixels including pixels each having a plurality of photoelectric conversion units formed for one microlens are arranged in a two-dimensional array, wherein the pixel has a first member configuring a waveguide that guides light condensed by the microlens to the center of the pixel, the first member is disposed on an upper portion on a light incident surface side of a semiconductor substrate in which the plurality of photoelectric conversion units are formed in cross-sectional view, and is disposed so as to avoid an in-pixel separation section that physically separates the plurality of photoelectric conversion units in plan view.

[0007] One aspect of the present disclosure is an electronic device comprising a light detection unit and a control unit that performs autofocus control based on phase difference information obtained from the light detection unit, wherein the light detection unit comprises a pixel array unit in which a plurality of pixels, including a pixel on which a plurality of photoelectric conversion units are formed for a single microlens, are arranged in a two-dimensional array, and the pixels are electronic devices in which a first member constituting a waveguide that guides the light focused by the microlens to the center of the pixel is arranged in a cross-sectional view on the upper part of the light incident surface side of the semiconductor substrate on which the plurality of photoelectric conversion units are formed, and in a plan view avoids an intra-pixel separation unit that physically separates the plurality of photoelectric conversion units.

[0008] Furthermore, the optical detection device and electronic equipment, which are aspects of this disclosure, may be independent devices or internal blocks constituting a single device.

[0009] This figure shows an example configuration of one embodiment of a photodetector to which the present disclosure is applied. This figure shows a first example of the pixel configuration. This figure shows a second example of the pixel configuration. This figure shows a third example of the pixel configuration. This figure shows a fourth example of the pixel configuration. This figure shows a fifth example of the pixel configuration. This figure shows a sixth example of the pixel configuration. This figure shows a modified version of the first example of the pixel configuration. This figure shows a modified version of the first example of the pixel configuration. This figure shows a seventh example of the pixel configuration. This figure shows an eighth example of the pixel configuration. This figure shows a ninth example of the pixel configuration. This figure shows a tenth example of the pixel configuration. This figure shows a modified version of the tenth example of the pixel configuration. This figure shows an eleventh example of the pixel configuration. This figure shows a modified version of the eleventh example of the pixel configuration. This figure shows a twelfth example of the pixel configuration. This figure shows a modified version of the twelfth example of the pixel configuration. This figure shows an example of the layout of pixels arranged in a two-dimensional array in the pixel array section. This figure shows a thirteenth example of the pixel configuration. This figure shows a modified version of the thirteenth example of the pixel configuration. This figure shows a fourteenth example of the pixel configuration. This figure shows a modified version of the fourteenth example of the pixel configuration. This figure shows a modified version of the fourteenth example of the pixel configuration. This figure illustrates the advantages of the pixel structure to which this disclosure applies. This figure illustrates the problems of the conventional pixel structure. This figure shows an example of a profile when the conventional pixel structure is adopted. This figure shows an example of a profile when the pixel structure to which this disclosure applies is adopted. This figure shows an example configuration of an embodiment of an electronic device equipped with a photodetector to which this disclosure applies.

[0010] <Configuration of the Photodetector> Figure 1 is a diagram showing an example configuration of one embodiment of a photodetector to which the present disclosure is applied. The photodetector 1 is configured as a solid-state imaging device such as a CMOS (Complementary Metal Oxide Semiconductor) type image sensor. As shown in Figure 1, the photodetector 1 consists of a pixel array unit 21, a vertical drive unit 22, a column signal processing unit 23, a horizontal drive unit 24, an output unit 25, and a control unit 26.

[0011] The pixel array section 21 has a plurality of pixels 31 arranged in a two-dimensional array on a semiconductor substrate made of silicon (Si) or the like. Each pixel 31 has a photoelectric conversion section composed of a photodiode (PD), a pixel transistor, and the like. For each row of the plurality of pixels 31 arranged in a two-dimensional array in the pixel array section 21, a pixel drive line 32 is formed and connected to a vertical drive section 22, and a vertical signal line 33 is formed for each column and connected to a column signal processing section 23.

[0012] The vertical drive unit 22 consists of a shift register, an address decoder, etc., and drives each pixel 31 arranged in the pixel array unit 21. The signals output from the pixels 31 selected and scanned by the vertical drive unit 22 are supplied to the column signal processing unit 23 through the vertical signal line 33. The column signal processing unit 23 performs predetermined signal processing (for example, AD conversion) on the signals output from each pixel 31 in the selected row through the vertical signal line 33 for each pixel column of the pixel array unit 21, and temporarily holds the signal after signal processing.

[0013] The horizontal drive unit 24 consists of a shift register, an address decoder, etc., and sequentially selects the unit circuits corresponding to the pixel sequences of the column signal processing unit 23. Through the selection scan by the horizontal drive unit 24, the signals processed by the column signal processing unit 23 are output to the output unit 25 via the horizontal signal line 34. The output unit 25 performs predetermined signal processing on the signals sequentially input from each of the column signal processing units 23 via the horizontal signal line 34, and outputs the resulting signal.

[0014] The control unit 26 consists of a timing generator and the like that generates various timing signals, and controls the drive of the vertical drive unit 22, the column signal processing unit 23, and the horizontal drive unit 24 based on the various timing signals generated by the timing generator.

[0015] <Pixel Configuration> The configuration of the pixels 31 arranged in a two-dimensional array in the pixel array section 21 of the light detection device 1 will be described below.

[0016] <<First Embodiment>> Figure 2 is a diagram showing a first example of the configuration of a pixel 31. In Figure 2, examples of the cross-sectional and planar configurations of pixels 31R, 31G, and 31B, which are located in a specific region among a plurality of pixels 31 arranged in a two-dimensional array in the pixel array section 21, are shown. The cross-sectional configuration on the left side of the figure corresponds to the A-A' cross-section in the planar configuration on the right side of the figure, and the planar configuration on the right side shows the planar configuration when focusing on the high refractive index member 44 in the cross-sectional configuration on the left side. In other words, in the planar configuration on the right side of the figure, structures that exist in layers different from the layer in which the high refractive index member 44 is formed are represented by dashed lines. These relationships are the same in other figures described later.

[0017] Pixel 31R is equipped with a color filter 45R corresponding to the red wavelength band, and is a pixel that generates an electric charge corresponding to the red wavelength component from light transmitted through the color filter 45R. Pixel 31G is equipped with a color filter 45G corresponding to the green wavelength band, and is a pixel that generates an electric charge corresponding to the green wavelength component from light transmitted through the color filter 45G. Pixel 31B is equipped with a color filter corresponding to the blue wavelength band, and is a pixel that generates an electric charge corresponding to the blue wavelength component from light transmitted through the color filter.

[0018] As shown in the planar configuration of Figure 2, in the pixel array section 21, the color filters of the pixels 31 are arranged in a Bayer array, with pixels 31G arranged in a checkerboard pattern, and pixels 31R and pixels 31B arranged alternately in rows in the remaining area. In Figure 2, a 2x2 area of ​​pixels is shown as a pixel for phase difference detection, but all pixels arranged in the pixel array section 21 can be used as pixels for phase difference detection. The light detection device 1 can generate a signal for autofocus (AF) control using the image plane phase difference method as a signal obtained from the pixels for phase difference detection.

[0019] Furthermore, pixels arranged in a portion of the pixel array 21 may be designated as pixels for phase difference detection, while pixels arranged in the remaining portion may be designated as ordinary pixels. In other words, in the pixel array 21, pixels for phase difference detection can be arranged together with ordinary pixels. Specifically, in the pixel array 21, pixels 31R, 31G, and 31B, each consisting of a structure in which one photoelectric conversion unit is provided for one microlens, can be arranged in a Bayer array as ordinary pixels. In addition, the pixels arranged in the pixel array 21 may include pixels 31R, 31G, and 31B, each consisting of a structure in which multiple photoelectric conversion units are provided for one microlens, as pixels for phase difference detection.

[0020] Pixel 31R has a structure in which two photoelectric conversion units 61-1 and 61-2 are provided for one microlens 46. In pixel 31R, light focused by the microlens 46 passes through the color filter 45R and is incident on the photoelectric conversion unit 61-1 and the photoelectric conversion unit 61-2, respectively. The microlens 46 is a lens (on-chip lens) with a circular shape in plan view, and it focuses the light incident on it. The photoelectric conversion units 61-1 and 61-2 are composed of, for example, n-type photodiodes (PDs) formed on a semiconductor substrate 41. In pixels 31G and 31B, similar to pixel 31R, a structure is provided in which two photoelectric conversion units are provided for one microlens, and light focused by the microlens passes through color filters corresponding to each color and is incident on each of the two photoelectric conversion units.

[0021] In Figure 2, in a plan view, inter-pixel isolation sections 51 are formed in a grid pattern surrounding each pixel (photoelectric conversion section), including pixels 31R, 31G, and 31B. The inter-pixel isolation sections 51 are formed, for example, by embedding a substance (material) in trenches formed in the semiconductor substrate 41 on which the photoelectric conversion sections are formed. Here, if the side of the main surface of the semiconductor substrate 41 on which the wiring layer is provided is considered the front surface, and the side opposite to the front surface (light incident surface) is considered the back surface, then, for example, the inter-pixel isolation sections 51 can be formed by embedding a substance in trenches formed from the back surface side of the semiconductor substrate 41. These trenches may be non-penetrating trenches that do not penetrate to the front surface side of the semiconductor substrate 41. Walls 52 are provided between color filters, such as between color filter 45R and color filter 45G, to avoid color mixing. By forming a film 42 having a fixed charge on the semiconductor substrate 41, the dark current generated in the photoelectric conversion sections 61-1 and 61-2 can be suppressed. For example, tantalum oxide (TaO) can be used as the material for the film 42.

[0022] In the pixel 31R, an intrapixel separation section 62 is formed on the semiconductor substrate 41 to separate the photoelectric conversion section 61-1 and the photoelectric conversion section 61-2, which are formed with respect to the microlens 46, into left and right sections within the pixel. The intrapixel separation section 62 is a separation section that physically separates the photoelectric conversion section 61-1 and the photoelectric conversion section 61-2, and is made of polysilicon (Poly Si) or the like. The intrapixel separation section 62 is formed as a protrusion that extends outwards toward the center of the pixel 31R. That is, the intrapixel separation section 62 is formed as a protrusion that extends outwards from a predetermined part of the interpixel separation section 51 which is formed in a grid pattern in a plan view, and the protrusions extending from opposing parts do not contact the central part of the pixel 31R, creating a structure that looks like a region (central region) corresponding to the light-gathering position (light-gathering point) by the microlens 46 has been cut out.

[0023] In the pixel 31R, a peripheral member 43 and a high refractive index member 44 are formed in the intermediate layer between the color filter 45R and the semiconductor substrate 41. The high refractive index member 44 is configured as a waveguide that guides the light focused by the microlens 46 to the central part of the pixel 31R. The high refractive index member 44 has a higher refractive index than the peripheral member 43 formed around it. The high refractive index member 44 can be formed using a dielectric material such as silicon nitride (SiN), titanium oxide (TiO2), or tantalum oxide (Ta2O5). In addition, the high refractive index member 44 can be made of a material with a refractive index n ≥ 1.9. The high refractive index member 44 has a rectangular parallelepiped shape, and in a plan view, it is positioned so that the second direction (horizontal direction in the figure), which is perpendicular to the first direction (vertical direction in the figure) in which the pixel separation portion 62 is located, is the longitudinal direction, corresponding to the portion in which the pixel separation portion 62 is cut out within the pixel 31R. The high refractive index member 44 has at least a length that allows it to straddle the photoelectric conversion unit 61-1 and the photoelectric conversion unit 61-2 in a plan view.

[0024] In other words, the high refractive index member 44 is positioned between the color filter 45R and the semiconductor substrate 41 in cross-sectional view, and is arranged to avoid the in-pixel separation portion 62 that physically separates the photoelectric conversion portion 61-1 and the photoelectric conversion portion 61-2 in plan view. Specifically, the inter-pixel separation portion 51 separates the portion of the pixel 31R excluding the area corresponding to the center of the pixel 31R in plan view by a physical separation portion formed on the semiconductor substrate 41 (separating the photoelectric conversion portion 61-1 and the photoelectric conversion portion 61-2), and the high refractive index member 44 is positioned in the area corresponding to the center of the pixel 31R in plan view. In the pixel 31R, by positioning the high refractive index member 44 to avoid the in-pixel separation portion 62 in plan view, it becomes possible to concentrate the light from the microlens 46 in a way that crushes it in the first direction (vertical direction in the figure) where the in-pixel separation portion 62 is located, thereby suppressing the absorption of light by the in-pixel separation portion 62 which contains polysilicon.

[0025] In pixels 31G and 31B, similar to pixel 31R, the high refractive index member 44 is positioned between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view, and avoids the in-pixel separation section 62 that physically separates the photoelectric conversion section in a plan view. In pixels 31G and 31B as well, the high refractive index member 44 can suppress the absorption of light from the microlens 46 by the in-pixel separation section 62.

[0026] In this way, in pixels 31R, 31G, and 31B, which are configured as pixels for phase difference detection, the high refractive index member 44 is positioned between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view, and avoids the in-pixel separation section 62 that physically separates the photoelectric conversion section in a plan view. This suppresses the absorption of light from the microlens 46 by the in-pixel separation section 62, thereby improving the quantum efficiency (QE) of photoelectric conversion.

[0027] Figure 3 shows a second example of the configuration of pixel 31. In Figure 3, parts corresponding to those in Figure 2 are denoted by the same reference numerals, and their explanations are omitted as appropriate.

[0028] In Figure 3, in pixels 31R, 31G, and 31B, the high refractive index members 44 are positioned between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view, and avoid the pixel separation portion 62 in a plan view. The high refractive index members 44 have a rectangular parallelepiped shape and a refractive index higher than that of the surrounding members 43.

[0029] In Figure 3, the high refractive index member 44 is formed such that its width is greater than the width of the cut-out portion of the pixel separation portion 62. That is, as shown in the planar configuration of Figure 3, a part of the high refractive index member 44 overlaps with the pixel separation portion 62. Specifically, in Figure 3, when the width of the cut-out portion of the pixel separation portion 62 is W1 and the width of the high refractive index member 44 is W3, the relationship is as shown in the following equation (1).

[0030] W3 > W1 ... (1)

[0031] In Figure 2, when the width of the cut-out portion of the pixel separation portion 62 is denoted as W1 and the width of the high refractive index member 44 is denoted as W2, the relationship shown in the following equation (2) holds true, and the width of the high refractive index member 44 is either the same as the width of the cut-out portion of the pixel separation portion 62, or narrower than the width of the cut-out portion of the pixel separation portion 62.

[0032] W2 ≤ W1 ... (2)

[0033] Thus, in pixels 31R, 31G, and 31B configured as pixels for phase difference detection, the width of the high refractive index member 44 can be less than or equal to the width of the pixel separation portion 62, or it may be wider than the width of the pixel separation portion 62. Even if a part of the high refractive index member 44 overlaps with the pixel separation portion 62 in the pixels for phase difference detection, the high refractive index member 44 can suppress the absorption of light from the microlens 46 by the pixel separation portion 62.

[0034] Figure 4 shows a third example of the configuration of pixel 31. In Figure 4, parts corresponding to those in Figure 2 are denoted by the same reference numerals, and their explanations are omitted as appropriate.

[0035] In Figure 4, in pixels 31R, 31G, and 31B, the high refractive index members 44 are positioned between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view, and avoid the pixel separation portion 62 in a plan view. The high refractive index members 44 have a rectangular parallelepiped shape and a refractive index higher than that of the surrounding members 43.

[0036] In Figure 4, the high refractive index member 44 is arranged across multiple pixels adjacent to each other on the left and right. Specifically, as shown in the upper part of the planar configuration of Figure 4, one high refractive index member 44 is commonly arranged in adjacent pixels 31G and 31R, corresponding to the portion where the pixel separation portion 62 within each pixel is cut out. Also, as shown in the lower part of the planar configuration of Figure 4, one high refractive index member 44 is commonly arranged in adjacent pixels 31B and 31G, corresponding to the portion where the pixel separation portion 62 within each pixel is cut out.

[0037] Thus, in pixels 31R, 31G, and 31B, which are configured as pixels for phase difference detection, the high refractive index member 44 may be provided for each pixel, or it may be provided in common for adjacent pixels. Even when one high refractive index member 44 is provided in common for multiple pixels for phase difference detection, the high refractive index member 44 in each pixel can suppress the absorption of light from the microlens 46 by the pixel separation section 62. In Figure 4, a configuration is shown in which a high refractive index member 44 is provided in common for two adjacent pixels for phase difference detection, but the high refractive index member 44 may be provided in common for three or more pixels for phase difference detection. A single high refractive index member 44 may include a structure in which multiple high refractive index members 44 are connected.

[0038] Figure 5 shows a fourth example of the configuration of the pixel 31. In Figure 5, parts corresponding to those in Figure 2 are denoted by the same reference numerals, and their explanations are omitted as appropriate.

[0039] In Figure 5, in pixels 31R, 31G, and 31B, the high refractive index member 44 is positioned between the color filter of each color and the semiconductor substrate 41 in a cross-sectional view, and avoids the pixel separation portion 62 in a plan view.

[0040] As shown in the cross-sectional configuration of Figure 5, in pixel 31R, the high refractive index member 44 is formed to have a tapered shape, narrowing in width from the color filter 45R side toward the semiconductor substrate 41 side. That is, in cross-sectional view, the high refractive index member 44 has a shape in which the slope is inclined with respect to the direction normal to the back surface of the semiconductor substrate 41. The high refractive index member 44 has a higher refractive index than the surrounding member 43. In pixels 31G and 31B, a high refractive index member 44 with a tapered shape is provided, similar to pixel 31R.

[0041] As described above, in the pixels 31R, 31G, and 31B configured as phase difference detection pixels, the shape of the high refractive index member 44 in each pixel is not limited to a rectangular parallelepiped shape, and may be a tapered shape. Even when the high refractive index member 44 is formed in a tapered shape in a phase difference detection pixel, the high refractive index member 44 can suppress the light from the microlens 46 from being absorbed by the in-pixel isolation portion 62.

[0042] FIG. 6 is a diagram showing a fifth example of the configuration of the pixel 31. In FIG. 6, portions corresponding to those in FIG. 2 are denoted by the same reference numerals, and descriptions thereof are omitted as appropriate.

[0043] In FIG. 6, in the pixels 31R, 31G, and 31B, the high refractive index member 44 is disposed between the color filter of each color and the semiconductor substrate 41 in a cross-sectional view, and is arranged so as to avoid the in-pixel isolation portion 62 in a plan view.

[0044] As shown by the cross-sectional configuration and planar configuration in FIG. 6, in the pixel 31R, the high refractive index member 44 is configured as a cylindrical lens having a shape obtained by cutting out a part of a cylinder. That is, the high refractive index member 44 has a shape of a convex lens (plano-convex lens) in a cross-sectional view. The high refractive index member 44 has a refractive index higher than that of the surrounding member 43. In the pixel 31R, light is condensed in two stages by the microlens 46 and the high refractive index member 44 configured as a cylindrical lens. In the pixels 31G and 31B, similarly to the pixel 31R, the high refractive index member 44 configured as a cylindrical lens is provided.

[0045] As described above, in the pixels 31R, 31G, and 31B configured as phase difference detection pixels, the shape of the high refractive index member 44 in each pixel may be a convex lens. Even when the high refractive index member 44 is formed in a convex lens shape in a phase difference detection pixel, the high refractive index member 44 can suppress the light from the microlens 46 from being absorbed by the in-pixel isolation portion 62.

[0046] FIG. 7 is a diagram showing a sixth example of the configuration of the pixel 31. In FIG. 7, portions corresponding to those in FIG. 2 are denoted by the same reference numerals, and descriptions thereof are omitted as appropriate.

[0047] In FIG. 7, in the pixel 31R, pixel 31G, and pixel 31B, a high-refractive-index member 44 is disposed between the color filter of each color and the semiconductor substrate 41 in a cross-sectional view, so as to avoid the intra-pixel separation portion 62 within the pixel in a plan view.

[0048] As shown in the cross-sectional configuration and planar configuration of FIG. 7, in the pixel 31R, the high-refractive-index member 44 is configured as a metalens. The metalens has a structure composed of pillars arranged in a predetermined pattern and a filler filled in portions excluding the pillars. Here, the high-refractive-index member 44 is used as the pillars, and the surrounding member 43 is used as the filler. The pillars are made of a high-refractive-index material, and the filler is made of a material having a refractive index lower than that of the pillars. Therefore, the high-refractive-index member 44 has a refractive index higher than that of the surrounding member 43. In the pixel 31R, light is condensed in two stages by the microlens 46 and the high-refractive-index member 44 configured as a metalens. In the pixel 31G and pixel 31B, similarly to the pixel 31R, the high-refractive-index member 44 configured as a metalens is provided.

[0049] In the pixel 31R, pixel 31G, and pixel 31B configured as phase difference detection pixels, the shape of the high-refractive-index member 44 in each pixel may be a shape corresponding to (the pillars of) the metalens. Even when the shape of the high-refractive-index member 44 in each pixel is set to a shape corresponding to the metalens, the high-refractive-index member 44 can suppress the light from the microlens 46 from being absorbed by the intra-pixel separation portion 62.

[0050] FIG. 8 is a diagram illustrating a modification of the first example of the configuration of the pixel 31. In FIG. 8, portions corresponding to those in FIG. 2 are denoted by the same reference numerals, and descriptions thereof are omitted as appropriate.

[0051] In FIG. 8, in the pixel 31R, pixel 31G, and pixel 31B, a high-refractive-index member 44 is disposed between the color filter of each color and the semiconductor substrate 41 in a cross-sectional view, so as to avoid the intra-pixel separation portion 62 within the pixel in a plan view. The high-refractive-index member 44 has a rectangular parallelepiped shape and has a refractive index higher than that of the surrounding member 43.

[0052] As shown in the cross-sectional configuration of Figure 8, films 71 and 42 are stacked on the light incident surface side of the semiconductor substrate 41. That is, in pixel 31R, a film 71 that acts as a stopper during etching is formed below the high refractive index member 44. For example, aluminum oxide (AlO) can be used as the material for film 71. In pixels 31G and 31B, similar to pixel 31R, a film 71 acting as a stopper film is provided below the high refractive index member 44.

[0053] Figure 9 shows a modified example of the first example of the configuration of the pixel 31. In Figure 9, parts corresponding to those in Figure 8 are given the same reference numerals, and their explanations are omitted as appropriate.

[0054] In Figure 9, in pixels 31R, 31G, and 31B, the high refractive index members 44 are positioned between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view, and avoid the pixel separation portion 62 in a plan view. The high refractive index members 44 have a rectangular parallelepiped shape and a refractive index higher than that of the surrounding members 43.

[0055] As shown in the cross-sectional view of Figure 9, in the pixel 31R, the high refractive index member 44 has a multilayer film structure in which a first layer 44-1, a second layer 44-2, and a third layer 44-3 are stacked in that order. The first layer 44-1 can be made of a dielectric material such as silicon nitride (SiN), titanium oxide (TiO2), or tantalum oxide (Ta2O5). The second layer 44-2 can be made of a dielectric material such as silicon nitride (SiN), but a different material from that used for the first layer 44-1 is used. The third layer 44-3 can be made of a dielectric material such as silicon nitride (SiN), but a different material from that used for the second layer 44-2 is used. The third layer 44-3 may be made of the same material as the first layer 44-1.

[0056] In pixels 31G and 31B, similar to pixel 31R, the high refractive index member 44 has a multilayer film structure in which the first layer 44-1 to the third layer 44-3 are stacked. In the cross-sectional view of Figure 9, a structure in which three layers of film are stacked is shown as the multilayer film structure of the high refractive index member 44, but two or more layers of film may be stacked. Also, in the cross-sectional view of Figure 9, a structure in which a film 71 as a stopper film is provided on the light incident surface side of the semiconductor substrate 41 is shown, but the film 71 is not required.

[0057] As described above, in the light detection device 1, the pixel array section 21 has a plurality of pixels arranged in a two-dimensional array, including pixels for phase difference detection, each having photoelectric conversion sections 61-1 and 61-2 formed on a single microlens 46. In the pixels for phase difference detection, a high refractive index member 44, which constitutes a waveguide that guides the light focused by the microlens 46 to the center of the pixel, is positioned in a cross-sectional view on the upper part of the light incident surface side of the semiconductor substrate 41 on which the photoelectric conversion sections 61-1 and 61-2 are formed, and avoids the in-pixel separation section 62 that physically separates the photoelectric conversion sections 61-1 and 61-2 in a plan view. With this structure, the high refractive index member 44 can suppress the absorption of light from the microlens 46 by the in-pixel separation section 62, thereby improving the quantum efficiency (QE) of photoelectric conversion.

[0058] <<Second Embodiment>> Figure 10 shows a seventh example of the configuration of the pixel 31. In Figure 10, parts corresponding to those in Figure 2 are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0059] In Figure 10, in pixels 31G and 31B, the high refractive index member 44 is positioned between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view, and avoids the pixel separation portion 62 in a plan view. The high refractive index member 44 has a rectangular parallelepiped shape and a refractive index higher than that of the surrounding member 43.

[0060] Comparing the high refractive index member 44 located in pixel 31G with the high refractive index member 44 located in pixel 31B, the length of the high refractive index member 44 in pixel 31G is formed to be longer than the length of the high refractive index member 44 in pixel 31B. Specifically, when the length of the high refractive index member 44 in pixel 31G is L1 and the length of the high refractive index member 44 in pixel 31B is L2, the relationship is as shown in the following equation (3).

[0061] L1 > L2 ... (3)

[0062] Furthermore, in Figure 10, in pixel 31R, the high refractive index member 44 is not provided in the portion where the pixel separation part 62 is cut out. In this way, in pixels 31R, 31G, and 31B, the presence or absence of the high refractive index member 44 and the shape (size) of the high refractive index member 44 can be changed in accordance with the color filters of each color. For example, since the red wavelength component has a higher reflectivity than the green and blue wavelength components, reflection can be suppressed by not providing the high refractive index member 44 in pixel 31R. Also, the size of the high refractive index members 44 placed in pixels 31G and 31B can be adjusted according to the characteristics of the green and blue wavelength components.

[0063] Note that the presence or absence and size of the high refractive index member 44 in each pixel shown in Figure 10 are examples, and other structures may be adopted. For example, a high refractive index member 44 may be provided in pixel 31R (for example, by providing a high refractive index member 44 that is shorter than that of other pixels), or the length of the high refractive index member 44 in pixel 31G may be shorter than or the same as the length of the high refractive index member 44 in pixel 31B.

[0064] Figure 11 shows an eighth example of the configuration of the pixel 31. In Figure 11, parts corresponding to those in Figure 2 are denoted by the same reference numerals, and their explanations are omitted as appropriate.

[0065] In Figure 11, in pixels 31R, 31G, and 31B, the high refractive index member 44 is positioned between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view, and avoids the pixel separation portion 62 in a plan view. As shown in the planar configuration of Figure 11, in pixel 31R, the high refractive index member 44 has an H-shaped form in a plan view, which is point-symmetric with respect to the center of pixel 31R. The high refractive index member 44 has a higher refractive index than the surrounding member 43. In pixels 31G and 31B, a high refractive index member 44 with an H-shaped form is provided, similar to pixel 31R.

[0066] In the autofocus system using the image plane phase difference method, autofocus is controlled using the power ratio of the light photoelectrically converted by two photoelectric conversion units 61-1 and 61-2, each provided for a single microlens 46 in a pixel for phase difference detection. The separation ratio is an indicator of autofocus performance. In the pixels for phase difference detection arranged in the pixel array 21, an in-pixel separation unit 62 is provided, and oblique light corresponding to the image height position on a two-dimensional plane is incident on the photoelectric conversion unit 61-1 and the photoelectric conversion unit 61-2. At this time, if the oblique incident light is biased towards one of the photoelectric conversion units 61-1 and the photoelectric conversion unit 61-2, autofocus performance can be improved. To achieve this balance with the separation ratio (so that the incident light is biased towards one of the photoelectric conversion units), the high refractive index member 44 is arranged to form an H shape in plan view.

[0067] Thus, in pixels 31R, 31G, and 31B, which are configured as pixels for phase difference detection, a structure can be adopted in which the shape of the high refractive index member 44 within each pixel is H-shaped in plan view. By adopting such a structure, the high refractive index member 44 having an H-shape suppresses the absorption of light from the microlens 46 by the pixel separation section 62, and a separation ratio that improves autofocus performance can be achieved. Note that the shape of the high refractive index member 44 is not limited to an H-shape; other shapes are also acceptable as long as they can achieve a separation ratio that improves autofocus performance.

[0068] Figure 12 shows a ninth example of the configuration of the pixel 31. In Figure 12, parts corresponding to those in Figure 2 are denoted by the same reference numerals, and their explanations are omitted as appropriate.

[0069] As shown in the cross-sectional configuration of Figure 12, in pixels 31R, 31G, and 31B, the high refractive index member 44 is positioned between the microlens 46 and the color filters of each color. Also, as shown in the planar configuration of Figure 12, in pixels 31R, 31G, and 31B, the high refractive index member 44 is positioned to avoid the pixel separation portion 62. In pixels 31R, 31G, and 31B, the high refractive index member 44 has a rectangular parallelepiped shape and a refractive index higher than that of the surrounding member 43.

[0070] Thus, in pixels 31R, 31G, and 31B, which are configured as pixels for phase difference detection, a structure can be adopted in which the high refractive index member 44 is placed between the microlens 46 and each color filter, rather than between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view. Even when such a structure is adopted, the high refractive index member 44 provided on top of each color filter can suppress the absorption of light from the microlens 46 by the pixel separation section 62.

[0071] Figure 13 shows a tenth example of the configuration of the pixel 31. In Figure 13, parts corresponding to those in Figure 2 are denoted by the same reference numerals, and their explanations are omitted as appropriate.

[0072] As shown in the cross-sectional and planar configurations of Figure 13, the color filters for each color are arranged such that, among the 4x4 pixels arranged in a specific region of the pixel array 21, the 2x2 pixels in the upper right region are designated as pixel 31R, the 2x2 pixels in the upper left and lower right regions are designated as pixel 31G, and the 2x2 pixels in the lower left region are designated as pixel 31B.

[0073] In Figure 13, in pixels 31R, 31G, and 31B, the high refractive index members 44 are positioned between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view, and avoid the pixel separation portion 62 in a plan view. The high refractive index members 44 have a rectangular parallelepiped shape and a refractive index higher than that of the surrounding members 43.

[0074] If we compare the lengths of the high refractive index members 44 placed in pixels 31R, 31G, and 31B, we find that the lengths of the high refractive index members 44 differ to correspond to the color filters of each color. Specifically, if we let L1 be the length of the high refractive index member 44 in pixel 31R, L2 be the length of the high refractive index member 44 in pixel 31G, and L3 be the length of the high refractive index member 44 in pixel 31B, then, for example, the relationship shown in equation (4) below holds.

[0075] L3 > L2 > L1...(4)

[0076] Furthermore, as shown in the planar configuration of Figure 14, in the 2x2 pixels 31R located in the upper right region, the high refractive index members 44, which are positioned to avoid the pixel separation portion 62 within the left and right pixels 31R, may be positioned offset in a direction perpendicular to the direction in which the pixel separation portion 62 is positioned (the direction of arrow D1 in the figure). Similarly, in the 2x2 pixels 31G located in the upper left and lower right regions, the high refractive index members 44, which are positioned to avoid the pixel separation portion 62 within the left and right pixels 31G, may be positioned offset in a direction perpendicular to the direction in which the pixel separation portion 62 is positioned (the direction of arrow D2 in the figure). In other words, in pixels 31R and 31G, the high refractive index members 44 are positioned offset from the center of each pixel.

[0077] In the planar configuration of Figure 14, the high refractive index member 44 is not offset within the 2x2 pixel 31B located in the lower left region, but it may be offset from the center of the pixel 31B. Alternatively, the high refractive index member 44 may be placed without offset within pixel 31R or pixel 31G. In other words, the high refractive index member 44 can be offset in at least one of the pixels 31R, pixel 31G, and pixel 31B. Furthermore, the relationship between L1, L2, and L3 described above is not limited to the relationship shown in equation (4), but for example, the magnitude relationship may be changed for each color according to the optical characteristics, or the relationship may be L1 = L2 = L3.

[0078] Thus, the multiple pixels 31 arranged in a two-dimensional array in the pixel array section 21 are not limited to a Bayer array, but may be arranged in other array patterns, and a structure can be adopted in which the high refractive index members 44 arranged in pixels 31R, 31G, and 31B, which are configured as pixels for phase difference detection, have their shape and position changed to correspond to the color filters of each color. Even when such a structure is adopted, the high refractive index members 44, whose shape and position are changed to correspond to the color filters of each color, can suppress the absorption of light from the microlenses 46 by the pixel separation section 62.

[0079] <<Third Embodiment>> Figure 15 shows an eleventh example of the configuration of the pixel 31. In Figure 15, the same reference numerals are used for parts corresponding to those in Figure 2, and their descriptions are omitted as appropriate.

[0080] As shown in the planar configuration of Figure 15, in the pixel 31R, the internal pixel separation portion 62 is provided in a cross shape, and the internal pixel separation portion 62 provided in a cross shape has a structure that looks like the central area of ​​the pixel has been hollowed out. The high refractive index member 44 has the shape of a rectangular parallelepiped and, in a plan view, is positioned corresponding to the hollowed-out portion of the internal pixel separation portion 62 in the pixel 31R. The high refractive index member 44 has a refractive index higher than that of the surrounding member 43.

[0081] In pixels 31G and 31B, similar to pixel 31R, a high refractive index member 44 in the shape of a rectangular parallelepiped is positioned corresponding to the cut-out portion of the pixel separation section 62, which is arranged in a cross shape in a plan view. In Figure 15, in pixels 31R, 31G, and 31B, the high refractive index member 44 is positioned between the color filters of each color and the semiconductor substrate 41 in a cross view, and avoids the pixel separation section 62 in a plan view.

[0082] Furthermore, as shown in the planar configuration of Figure 16, the shape of the high refractive index member 44, which is positioned in pixels 31R, 31G, and 31B corresponding to the portion where the internal separation part 62 of the pixel is cut out, is not limited to a rectangular parallelepiped shape, but may be other shapes such as a convex lens, a cylindrical shape, or a cross shape. Moreover, in pixels 31R, 31G, and 31B, the high refractive index member 44 may have a structure in which its shape, position, and presence or absence are changed to correspond to the color filters of each color.

[0083] As described above, in pixels 31R, 31G, and 31B, which are configured as pixels for phase difference detection, a structure can be adopted in which a high refractive index member 44 is placed in a portion that is cut out from the central area of ​​the pixel in the pixel separation portion 62, which is arranged in a cross shape in a plan view, so as to avoid the pixel separation portion 62. Even when such a structure is adopted, the high refractive index member 44, which is placed so as to avoid the pixel separation portion 62, can suppress the absorption of light from the microlens 46 by the pixel separation portion 62.

[0084] <<Fourth Embodiment>> Figure 17 shows a twelfth example of the configuration of the pixel 31. In Figure 17, parts corresponding to those in Figure 2 are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0085] As shown in the planar configuration of Figure 17, each pixel 31R, which has a rectangular shape, has an internal pixel separation portion 62 provided on its diagonal. The internal pixel separation portion 62, which is provided in a cross shape corresponding to the diagonal, has a structure that looks like the central area of ​​the pixel has been hollowed out. The high refractive index member 44 has a rectangular parallelepiped shape and, in a planar view, is positioned corresponding to the portion of the pixel 31R where the internal pixel separation portion 62 has been hollowed out. The high refractive index member 44 has a refractive index higher than that of the surrounding member 43.

[0086] In pixels 31G and 31B, similar to pixel 31R, a high refractive index member 44 in the shape of a rectangular parallelepiped is positioned to correspond to the cut-out portion of the pixel separation section 62, which is provided in a cross shape corresponding to the diagonal in a plan view. In Figure 17, in pixels 31R, 31G, and 31B, the high refractive index member 44 is positioned between the color filters of each color and the semiconductor substrate 41 in a cross view, and avoids the pixel separation section 62 that physically separates the photoelectric conversion sections 61-1 to 61-4 in a plan view.

[0087] Furthermore, as shown in the planar configuration of Figure 18, the shape of the high refractive index member 44, which is positioned in pixels 31R, 31G, and 31B corresponding to the portion where the internal separation part 62 of the pixel is cut out, is not limited to a rectangular parallelepiped shape, but may be other shapes, such as a cylindrical shape. Moreover, in pixels 31R, 31G, and 31B, the high refractive index member 44 may have a structure in which its shape, position, and presence or absence are changed to correspond to the color filters of each color.

[0088] As described above, in pixels 31R, 31G, and 31B, which are configured as pixels for phase difference detection, various shapes and arrangements can be adopted for the shape and arrangement of the in-pixel separation section 62 that physically separates the multiple photoelectric conversion sections, and the high refractive index member 44 can be arranged to avoid the in-pixel separation section 62 which have various shapes and arrangements. By arranging the high refractive index member 44 to avoid the in-pixel separation section 62 which have various shapes and arrangements, it is possible to suppress the absorption of light from the microlens 46 by the in-pixel separation section 62.

[0089] <<Fifth Embodiment>> Figure 19 is a diagram showing an example of the layout of pixels 31 arranged in a two-dimensional array in the pixel array section 21. As shown in Figure 19, in the pixel array section 21, an in-pixel separation section 62 is provided in an oblique direction to physically separate the photoelectric conversion section 61-1 and the photoelectric conversion section 61-2 within the pixel for phase difference detection. For example, in the pixels 31 arranged in the pixel array section 21, the in-pixel separation section 62 is provided in an oblique direction that is downward to the left in a plan view for the pixels for phase difference detection arranged in the right region in the figure, and the in-pixel separation section 62 is provided in an oblique direction that is downward to the right in a plan view for the pixels for phase difference detection.

[0090] In the pixel array section 21, the inclination of the in-pixel separation section 62, which is provided diagonally within the pixel for phase difference detection, may be changed according to the image height position (image height coordinate) on the two-dimensional plane. Figures 20 to 22 show the configuration when the inclination of the in-pixel separation section 62 is changed according to the image height position.

[0091] Figure 20 shows a thirteenth example of the configuration of the pixel 31. In Figure 20, parts corresponding to those in Figure 2 are denoted by the same reference numerals, and their explanations are omitted as appropriate.

[0092] In the planar configuration of Figure 20, pixels 31R-1 and 31G-1 shown in the upper section and pixels 31R-2 and 31G-2 shown in the lower section are located in different areas on the pixel array 21, and the inclination of the pixel separation section 62 differs depending on the image height position of the area in which it is located. Specifically, the pixel separation section 62 provided in pixels 31R-1 and 31G-1 has a greater inclination than the pixel separation section 62 provided in pixels 31R-2 and 31G-2. For example, on the two-dimensional plane of the pixel array 21, the inclination of the pixel separation section 62 may be made smaller for pixels for phase difference detection located in the center, and larger for pixels for phase difference detection located in the periphery.

[0093] In the pixels used for phase difference detection, even when the inclination of the pixel separation portion 62 is changed according to the image height position, the portion of the pixel separation portion 62 corresponding to the pixel center is hollowed out, and a high refractive index member 44 is positioned corresponding to the hollowed-out portion. In Figure 20, the high refractive index member 44 has a rectangular parallelepiped shape and a refractive index higher than that of the surrounding member 43. That is, the high refractive index member 44 is positioned between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view, and is positioned to avoid the pixel separation portion 62 in a plan view.

[0094] Furthermore, as shown in the planar configuration of Figure 21, the shape of the high refractive index member 44 is not limited to a rectangular parallelepiped, but may be other shapes such as a convex lens. Moreover, as shown in the planar configuration of Figure 22, when the pixels 31R-1 and 31G-1 shown in the upper section and the pixels 31G-2 and 31B-2 shown in the lower section are arranged in different regions on the pixel array section 21, the shape, placement position, and presence or absence of the high refractive index member 44 may be changed to correspond to the color filters of each color. For example, as shown in the planar configuration of Figure 22, the high refractive index member 44 may not be provided for pixel 31R-1, but may be provided for pixels 31G-1, 31G-2, and 31B-2, with the length of the high refractive index member 44 of pixel 31B-2 being longer than the length of the high refractive index member 44 of pixels 31G-1 and 31G-2.

[0095] Thus, in pixels 31R, 31G, and 31B, which are configured as pixels for phase difference detection, the inclination can be changed according to the image height position when the pixel separation portion 62 is positioned diagonally in a plan view, and the high refractive index member 44 may be a color filter of each color or a structure whose shape is changed according to the image height position, as long as it is positioned corresponding to the center of the pixel (the light-gathering position by the microlens 46).

[0096] Figure 23 shows a 14th example of the configuration of the pixel 31. In Figure 23, the same reference numerals are used for parts corresponding to the cross-sectional configuration in Figure 2, and their explanations are omitted as appropriate.

[0097] In Figure 23, the left cross-sectional view shows the cross-sectional structure of pixels located at the image height center, i.e., the central part of the pixel array 21. The right cross-sectional view shows the cross-sectional structure of pixels located at the high image height, i.e., the peripheral part of the pixel array 21. Here, in the pixel array 21, the image height increases from the center to the periphery on a two-dimensional plane, so the pixels located at the periphery shown in the right cross-sectional view are high image height pixels.

[0098] In the pixel array section 21, incident light that has passed through the imaging lens is irradiated, so the pixels located at the periphery are illuminated by light from the subject at an oblique angle. As a result, the light-collecting position by the microlenses 46 is shifted from the photoelectric conversion section in the pixels located at the periphery of the pixel array section 21. In the pixel array section 21, the microlenses 46 of each pixel 31 are arranged to be continuously shifted toward the center according to the image height position on the two-dimensional plane. That is, the microlenses 46 of each pixel 31 are arranged to be eccentric toward the center as the image height increases. Specifically, as shown in the cross-sectional configuration on the right side of Figure 23, the microlenses 46 and color filters 45R and 45G of pixels 31R and 31G located at the periphery of the pixel array section 21 are arranged to be eccentric toward the center.

[0099] In Figure 23, the high refractive index member 44 is positioned between the color filters of each color and the semiconductor substrate 41 in a cross-sectional view, and is arranged to avoid the pixel separation portion 62 in a plan view. The shape of the high refractive index member 44 differs between the pixels for phase difference detection located in the center of the pixel array 21 and the pixels for phase difference detection located at the periphery. Specifically, as shown in the cross-sectional configuration on the left side of Figure 23, the high refractive index member 44 is shaped like a rectangular parallelepiped in the pixels 31R and 31G located in the center. On the other hand, as shown in the cross-sectional configuration on the right side of Figure 23, the high refractive index member 44 is shaped like a rectangular parallelepiped with a part cut out (a trapezoidal shape in cross-section) in the pixels 31R and 31G located at the periphery, depending on the light L incident at a predetermined angle. In the pixels for phase difference detection, pupil correction can be performed in a similar manner to a microlens 46 by changing the shape of the high refractive index member 44 according to the incident light.

[0100] The shape of the high refractive index member 44 for the phase difference detection pixels (high image height pixels) arranged at the periphery can be any shape corresponding to the incident light. For example, as shown in the cross-sectional configuration on the left side of Figure 24, it may be a right-angled trapezoid in cross-sectional view, or as shown in the cross-sectional configuration on the right side of Figure 24, it may be a parallelogram in cross-sectional view. Furthermore, as shown in the cross-sectional configuration of Figure 25, the shape of the high refractive index member 44 for the phase difference detection pixels (high image height pixels) arranged at the periphery may be changed to correspond to each color filter. Specifically, in the cross-sectional configuration on the left side of Figure 25, the shape of the high refractive index member 44, which is a right-angled trapezoid (width of the right-angled trapezoid and inclination of the slope), is different for pixels 31R and 31G. Also, in the cross-sectional configuration on the right side of Figure 25, the shape of the high refractive index member 44, which is a rectangular shape (width of the rectangle), is different for pixels 31R and 31G. In pixels used for phase difference detection, wavelength dispersion can be suppressed by changing the shape of the high refractive index member 44 according to the color filter of each color. For example, in a pixel used for phase difference detection (e.g., pixel 31R) where a color filter corresponding to a longer wavelength band (e.g., color filter 45R) is placed, the incident light in the longer wavelength band can be focused by placing a high refractive index member 44 with a larger shape.

[0101] As described above, in pixels 31R, 31G, and 31B, which are configured as pixels for phase difference detection, a structure can be adopted in which the shape of the high refractive index member 44 is shaped according to the image height position or according to the angle of incidence of light incident from the microlens 46. Even when such a structure is adopted, the high refractive index member 44, which has a shape according to the image height position and incident light, can suppress the absorption of light from the microlens 46 by the pixel separation section 62.

[0102] <Effects> Figure 26 illustrates the advantages of the pixel structure to which this disclosure is applied. As shown in Figure 26, in a pixel 31 configured as a pixel for phase difference detection, the high refractive index member 44, which constitutes a waveguide that guides the light focused by the microlens 46 to the center of the pixel, is positioned in a cross-sectional view at the upper part of the light incident surface side of the semiconductor substrate 41 on which the photoelectric conversion units 61-1 and 61-2 are formed, and is arranged to avoid the in-pixel separation unit 62 that physically separates the photoelectric conversion units 61-1 and 61-2 in a plan view. With such a structure, as shown in the plan view of Figure 26, the high refractive index member 44 makes it possible to focus the light focusing position S by the microlens 46 in a way that compresses (narrows) it in the first direction (vertical direction in the figure) where the in-pixel separation unit 62 is located, thereby enabling stronger focusing and suppressing light absorption by the in-pixel separation unit 62 which contains polysilicon. As a result, absorption by polysilicon can be significantly reduced, and the quantum efficiency (QE) of photoelectric conversion can be improved.

[0103] Here, for comparison, the problems of the conventional pixel structure will be explained with reference to Figure 27. As shown in Figure 27, in the pixel 31 configured as a pixel for phase difference detection, a high refractive index member 44 is not provided. Therefore, light is absorbed by the in-pixel separation section 62 that physically separates the photoelectric conversion sections 61-1 and 61-2 within the pixel, which may reduce the quantum efficiency of photoelectric conversion. As shown in the planar configuration of Figure 27, the in-pixel separation section 62 containing polysilicon is located at the light focusing position S by the microlens 46. As a result, light is absorbed by the polysilicon, reducing the quantum efficiency of photoelectric conversion. Although a method of adjusting the focusing position using a microlens with a high refractive index is conceivable, it is not possible to focus the light without overlapping the in-pixel separation section 62 due to the diffraction limit, and it becomes necessary to reduce the volume of the in-pixel separation section 62. Therefore, when using a pixel for phase difference detection, there is a need for a structure that can improve the quantum efficiency of photoelectric conversion, and this disclosure proposes the structure shown in Figure 26.

[0104] The simulation results by the inventors of this disclosure are shown in Figures 28 and 29. Figure 28 shows an example of a profile when a conventional pixel structure is adopted. Figure 29 shows an example of a profile when a pixel structure to which this disclosure is applied is adopted. In Figures 28 and 29, the horizontal axis represents the y-axis corresponding to the first direction (for example, the vertical direction in the planar configuration of Figure 26) in which the in-pixel separation portion 62 is arranged when viewing the pixel for phase difference detection in a planar view, with the area around y = 500 nm corresponding to the center of the pixel. The vertical axis represents the optical power, and the light focused by the microlens 46 has the greatest optical power at the center of the pixel.

[0105] Comparing the profile in Figure 28 with the profile in Figure 29, the waveform in Figure 29 has a steeper peak than the waveform in Figure 28, and is narrowed in the y-axis direction with respect to around y = 500 nm. In other words, the profile in Figure 29 shows that by adopting the pixel structure to which this disclosure is applied and providing a high refractive index member 44, the light focusing position S by the microlens 46 can be narrowed in the first direction (for example, the vertical direction of the planar configuration in Figure 26). In this way, by providing the high refractive index member 44, the overlap between the light focusing position S by the microlens 46 and the pixel isolation portion 62 is greatly improved, so that absorption by polysilicon contained in the pixel isolation portion 62 can be greatly reduced and the quantum efficiency (QE) of photoelectric conversion can be improved.

[0106] In the above explanation, a pixel for phase difference detection was described as having a structure in which multiple photoelectric conversion units are provided for a single microlens. However, it is also possible to consider the structure containing each of the photoelectric conversion units as a pixel. For example, a structure in which two photoelectric conversion units 61-1 and 61-2 are provided for a single microlens 46 may be composed of a pair of pixels consisting of a first pixel having photoelectric conversion unit 61-1 and a second pixel having photoelectric conversion unit 61-2.

[0107] <Configuration of the electronic device> Figure 30 shows an example of the configuration of one embodiment of an electronic device equipped with a light detection device to which the present disclosure is applied. The electronic device 101 is configured as a device having an imaging function, such as a camera, smartphone, tablet terminal, or mobile phone. As shown in Figure 30, the electronic device 101 consists of a photographic lens 121, a light detection unit 122, a signal processing unit 123, a compression / decompression unit 124, a control unit 125, an operation unit 126, a display unit 127, and a storage unit 128.

[0108] The photographic lens 121 focuses (forms an image) light (optical image) from the subject onto the light detection surface of the light detection unit 122. The photographic lens 121 is configured, for example, as a lens unit included in an optical lens barrel, and the optical mechanism (AF mechanism, etc.) is driven by a drive circuit under the control of the control unit 125 to realize functions such as autofocus. The light detection unit 122 detects the light incident from the photographic lens 121 and outputs a signal. The light detection unit 122 is configured, for example, as a light detection device 1 (Figure 1) including a solid-state imaging device such as a CMOS type image sensor. In the light detection unit 122, all pixels arranged in the pixel array can be used as pixels for phase difference detection as described above. That is, the light detection unit 122 can generate a signal for AF control using the image plane phase difference method as a signal obtained from the pixels for phase difference detection. In addition, the light detection unit 122 can generate a signal for generating image data as a signal obtained from the pixels for phase difference detection.

[0109] The signal processing unit 123, in accordance with the control unit 125, performs predetermined signal processing (e.g., white balance adjustment processing, color correction processing, etc.) on the signal output from the light detection unit 122 and outputs it as image data to the compression / decompression unit 124. The compression / decompression unit 124, in accordance with the control unit 125, performs compression encoding processing on the image data output from the signal processing unit 123 using a predetermined method. The compression / decompression unit 124 also performs decompression / decoding processing on the encoded image data supplied by the control unit 125 using a predetermined method, in accordance with the control unit 125. The predetermined method includes, for example, the JPEG (Joint Photographic Experts Group) method and the MPEG (Moving Picture Experts Group) method.

[0110] The control unit 125 is composed of a microcontroller having, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The CPU controls each part of the electronic device 101 by executing a program stored in the ROM. For example, the control unit 125 performs autofocus control based on phase difference information obtained from the light detection unit 122. The operation unit 126 is composed of, for example, buttons, and outputs signals to the control unit 125 according to user input operations. The display unit 127 is composed of, for example, an LCD (Liquid Crystal Display), an organic EL display, etc., and displays an image corresponding to the image data supplied from the control unit 125. The storage unit 128 is a recording medium such as a portable semiconductor memory, and stores image data compressed and encoded by the compression / decompression unit 124. The storage unit 128 also supplies the stored image data to the control unit 125 according to control from the control unit 125.

[0111] <Examples of Use of the Light Detection Device> Figure 30 shows a configuration in which the light detection device 1 to which the present disclosure is applied is mounted on an electronic device 101. However, the light detection device 1 to which the present disclosure is applied can be used in various cases for sensing light such as visible light, infrared light, ultraviolet light, and X-rays. In other words, the light detection device 1 to which the present disclosure is applied can be used not only in the field of appreciation, where images for appreciation are taken, but also in devices used in fields such as transportation, home appliances, medical care and healthcare, security, beauty, sports, or agriculture.

[0112] Specifically, in the field of appreciation, for example, the light detection device 1 to which this disclosure is applied can be used in devices for capturing images for appreciation, such as digital cameras, smartphones, and mobile phones with camera functions. In the field of traffic, for example, the light detection device 1 to which this disclosure is applied can be used in devices used for traffic, 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, or for recognizing the driver's condition, surveillance cameras that monitor moving vehicles and roads, and distance measuring sensors that measure distances between vehicles.

[0113] In the field of home appliances, for example, the photodetector 1 to which this disclosure is applied can be used in devices used in home appliances such as television sets, refrigerators, and air conditioners to capture user gestures and operate the device according to those gestures. In the field of medical and healthcare, for example, the photodetector 1 to which this disclosure is applied can be used in devices used for medical and healthcare purposes, such as endoscopes and devices that perform angiography by receiving infrared light. In the field of security, for example, the photodetector 1 to which this disclosure is applied can be used in devices used for security purposes, such as surveillance cameras for crime prevention and cameras for person authentication.

[0114] In the field of beauty, for example, the light detection device 1 to which this disclosure is applied can be used in devices used for beauty purposes, such as skin measuring devices for photographing skin or microscopes for photographing the scalp. In the field of sports, for example, the light detection device 1 to which this disclosure is applied can be used in devices used for sports purposes, such as action cameras and wearable cameras for sports use. In the field of agriculture, for example, the light detection device 1 to which this disclosure is applied can be used in devices used for agriculture, such as cameras for monitoring the condition of fields and crops.

[0115] The embodiments described herein are not limited to those described above, and various modifications are possible without departing from the spirit of this disclosure. For example, the embodiments described above may be implemented individually or in combination with other embodiments. Furthermore, the effects described herein are merely illustrative and not limiting, and other effects may also occur.

[0116] Furthermore, this disclosure can take the following form.

[0117] (1) A light detection device comprising a pixel array portion in which a plurality of pixels, including a pixel having a plurality of photoelectric conversion units formed on a single microlens, are arranged in a two-dimensional array, wherein the pixels have a first member which constitutes a waveguide that guides the light focused by the microlens to the center of the pixel, and the first member is positioned in a cross-sectional view on the upper part of the light incident surface side of the semiconductor substrate on which the plurality of photoelectric conversion units are formed, and in a plan view avoids an intra-pixel separation portion that physically separates the plurality of photoelectric conversion units. (2) The light detection device according to (1), wherein in a plan view the intra-pixel separation portion is separated in part from the region corresponding to the center of the pixel by a physical separation portion formed on the semiconductor substrate, and the first member is positioned in the region corresponding to the center of the pixel in a plan view. (3) The light detection device according to (1) or (2), wherein in a cross-sectional view the first member is provided between a filter corresponding to the wavelength band for each color and the semiconductor substrate. (4) The light detection device according to (1) or (2), wherein the first member is provided between the microlens and a filter corresponding to the wavelength band for each color in cross-sectional view. (5) The light detection device according to any one of (1) to (4), wherein the first member is formed of a dielectric material having a refractive index higher than the refractive index of a second member provided around the first member. (6) The light detection device according to any one of (1) to (5), wherein the first member is a rectangular parallelepiped, a convex lens, a metalens, a cylinder, or a tapered shape. (7) The light detection device according to any one of (1) to (6), wherein the first member is arranged in a second direction which is perpendicular to the first direction in which the pixel separation portion is arranged in plan view, and the width of the first member is less than or equal to the width of the cut-out portion of the pixel separation portion. (8) The light detection device according to any one of (1) to (6), wherein the first member is arranged in a second direction which is perpendicular to the first direction in which the pixel-in-separation portion is arranged in a plan view, and the width of the first member is greater than the width of the cut-out portion of the pixel-in-separation portion. (9) The light detection device according to any one of (1) to (8), wherein the first member has at least a length that can straddle the plurality of photoelectric conversion portions in a plan view. (10) The light detection device according to any one of (1) to (8), wherein the first member is arranged to straddle the plurality of pixels.(11) The photodetector according to any one of (1) to (9), wherein the first member is provided on a specific pixel among a plurality of pixels that is provided with a filter corresponding to a wavelength band of a specific color. (12) The photodetector according to any one of (1) to (9), wherein the first member has a different shape depending on the filter corresponding to the wavelength band of each color. (13) The photodetector according to any one of (1) to (12), wherein a stopper film is formed on the light incident surface side of the semiconductor substrate. (14) The photodetector according to any one of (1) to (13), wherein the first member is composed of a multilayer film consisting of at least two or more layers. (15) The photodetector according to any one of (1) to (9), wherein the first member has a shape corresponding to the image height position on a two-dimensional plane in the pixel array. (16) The photodetector according to (15), wherein the first member has a shape corresponding to the incident light from the microlens. (17) The light detection device according to (15) or (16), wherein the first member has a different shape for the pixels located in the central part of the pixel array 21 and for the pixels located in the peripheral part. (18) The light detection device according to any one of (15) to (17), wherein the first member has a different shape depending on the filter corresponding to the wavelength band for each color. (19) The light detection device according to any one of (1) to (9), wherein the pixel separation part is arranged diagonally in a plan view and has an inclination corresponding to the image height position on the two-dimensional plane in the pixel array. (20) An electronic device comprising: a light detection unit and a control unit that performs autofocus control based on phase difference information obtained from the light detection unit, wherein the light detection unit comprises a pixel array unit in which a plurality of pixels, including a pixel on which a plurality of photoelectric conversion units are formed for a single microlens, are arranged in a two-dimensional array, and the pixels are configured such that a first member constituting a waveguide that guides the light focused by the microlens to the center of the pixel is positioned in the upper part of the light incident surface side of the semiconductor substrate on which the plurality of photoelectric conversion units are formed in cross-sectional view, and avoids an intra-pixel separation unit that physically separates the plurality of photoelectric conversion units in plan view.

[0118] 1. Photodetector, 21. Pixel array section, 22. Vertical drive section, 23. Column signal processing section, 24. Horizontal drive section, 25. Output section, 26. Control section, 31. Pixel, 31R, 31G, 31B. Pixel, 41. Semiconductor substrate, 42. Film, 43. Surrounding member, 44. High refractive index member, 44-1. First layer, 44-2. Second layer, 44-3. Third layer, 45R, 45G. Color filter, 46. Microlens, 51. Inter-pixel separation section, 52. Wall section, 61-1, 61-2. Photoelectric conversion section, 62. Intra-pixel separation section, 71. Film, 101. Electronic equipment, 121. Imaging lens, 122. Photodetector, 123. Signal processing section, 124. Compression / expansion section, 125. Control section, 126. Operation unit, 127 Display unit, 128 Storage unit

Claims

1. A light detection device comprising a pixel array section in which a plurality of pixels, each having a plurality of photoelectric conversion units formed on a single microlens, are arranged in a two-dimensional array, wherein each pixel has a first member that constitutes a waveguide for guiding the light focused by the microlens to the center of the pixel, and the first member is positioned in a cross-sectional view on the upper part of the light incident surface side of the semiconductor substrate on which the plurality of photoelectric conversion units are formed, and in a plan view avoids an intra-pixel separation section that physically separates the plurality of photoelectric conversion units.

2. The photodetector according to claim 1, wherein the pixel separation portion is separated in a plan view from the region corresponding to the center of the pixel by a physical separation portion formed on the semiconductor substrate, and the first member is positioned in a region corresponding to the center of the pixel in a plan view.

3. The photodetector according to claim 1, wherein the first member is provided between a filter corresponding to a wavelength band for each color and the semiconductor substrate in a cross-sectional view.

4. The light detection device according to claim 1, wherein the first member is provided between the microlens and a filter corresponding to the wavelength band for each color in a cross-sectional view.

5. The photodetector according to claim 1, wherein the first member is made of a dielectric material having a refractive index higher than that of the second member provided around the first member.

6. The light detection device according to claim 1, wherein the first member is a rectangular parallelepiped, a convex lens, a metalens, a cylinder, or a tapered shape.

7. The light detection device according to claim 1, wherein the first member is arranged in a second direction which is perpendicular to the first direction in which the pixel separation portion is arranged when viewed from above, and the width of the first member is less than or equal to the width of the cut-out portion of the pixel separation portion.

8. The light detection device according to claim 1, wherein the first member is arranged in a second direction which is perpendicular to the first direction in which the pixel separation portion is arranged when viewed from above, and the width of the first member is greater than the width of the cut-out portion of the pixel separation portion.

9. The photodetector according to claim 1, wherein the first member has at least a length that can span the plurality of photoelectric conversion units in a plan view.

10. The light detection device according to claim 1, wherein the first member is arranged across a plurality of pixels.

11. The light detection device according to claim 1, wherein the first member is provided on a specific pixel among the plurality of pixels that is provided with a filter corresponding to a specific wavelength band of a specific color.

12. The photodetector according to claim 1, wherein the first member has a different shape depending on the filter corresponding to the wavelength band of each color.

13. The photodetector according to claim 1, wherein a stopper film is formed on the light incident surface side of the semiconductor substrate.

14. The photodetector according to claim 1, wherein the first member is composed of a multilayer film consisting of at least two or more layers.

15. The light detection device according to claim 1, wherein the first member has a shape corresponding to the image height position on a two-dimensional plane in the pixel array portion.

16. The light detection device according to claim 15, wherein the first member has a shape corresponding to the incident light from the microlens.

17. The light detection device according to claim 16, wherein the first member has different shapes for the pixels located in the central part of the pixel array 21 and the pixels located in the peripheral part.

18. The photodetector according to claim 16, wherein the first member has a different shape depending on the filter corresponding to the wavelength band of each color.

19. The photodetector according to claim 1, wherein the pixel separation portion is arranged obliquely in a plan view and has an inclination corresponding to the image height position on a two-dimensional plane in the pixel array portion.

20. An electronic device comprising a light detection unit and a control unit that performs autofocus control based on phase difference information obtained from the light detection unit, wherein the light detection unit comprises a pixel array unit in which a plurality of pixels, including a pixel on which a plurality of photoelectric conversion units are formed for a single microlens, are arranged in a two-dimensional array, and the pixels have a first member that constitutes a waveguide for guiding the light focused by the microlens to the center of the pixel, which is arranged in a cross-sectional view on the upper part of the light incident surface side of the semiconductor substrate on which the plurality of photoelectric conversion units are formed, and avoids an intra-pixel separation unit that physically separates the plurality of photoelectric conversion units in a plan view.

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