Light detection device and electronic apparatus

Abstract

The present disclosure relates to a light detection device and an electronic device that improve charge transfer within a photoelectric conversion region in a pixel including an inter-pixel separation portion. The light detection device includes: a photoelectric conversion region formed in a semiconductor substrate; and a pixel separation part penetrating the semiconductor substrate and separating the photoelectric conversion region for each pixel. The pixel separation portion includes a first separation wall on a first surface side of the semiconductor substrate and a second separation wall on a second surface side of the semiconductor substrate, the second surface being opposite to the first surface. The first separation wall and the second separation wall have different widths, and with respect to a width from the photoelectric conversion region to the second separation wall in a direction perpendicular to the center line, a first width of a side center portion of the pixel is configured to be larger than a second width of a corner vicinity portion of the pixel, the photoelectric conversion area is divided into two parts in the horizontal direction or the vertical direction by the center line. The present disclosure is applicable, for example, to a solid-state imaging device, a ToF-type distance measurement sensor, or the like.

Description

Technical Field

[0001] This disclosure relates to light detection apparatuses and electronic devices, and more particularly, to light detection apparatuses and electronic devices for improving charge transfer in photoelectric conversion regions within pixels, including inter-pixel separation portions. Background Technology

[0002] In related technologies, there are solid-state imaging devices that form trenches between adjacent pixels and form an accumulation layer along the sidewalls of the trenches to suppress the generation of dark current (see, for example, Patent Document 1). Furthermore, there are solid-state imaging devices that form trenches of different widths on the front and back sides for pixel separation (see, for example, Patent Document 2). Reference List Patent documents

[0003] Patent Document 1: JP 2018-181910 A Patent Document 2: JP 2021-166304 A Summary of the Invention The technical problem that the invention aims to solve

[0004] When a P-type or N-type layer is formed on the sidewall of a trench, it is difficult to design charge transport when a potential difference is generated between the corner and the center of the edge of a pixel in a planar diagram.

[0005] This disclosure is made in view of this situation, and the purpose of this disclosure is to improve charge transport in the photoelectric conversion region of a pixel including an inter-pixel separation portion. Technical solutions to solve technical problems

[0006] A photodetector according to a first aspect of this disclosure includes: a photoelectric conversion region formed in a semiconductor substrate; and a pixel separation portion extending through the semiconductor substrate and separating the photoelectric conversion region for each pixel. The pixel separation portion includes a first separation wall on a first surface side of the semiconductor substrate and a second separation wall on a second surface side of the semiconductor substrate, the second surface being opposite to the first surface. The first separation wall and the second separation wall have different widths, and regarding the width of the photoelectric conversion region to the second separation wall in a direction perpendicular to a centerline, a first width at the edge center of the pixel is configured to be greater than a second width near the corner of the pixel, the centerline dividing the photoelectric conversion region in two in a horizontal or vertical direction.

[0007] An electronic device according to a second aspect of this disclosure includes a light detection device comprising: a photoelectric conversion region formed in a semiconductor substrate; and a pixel separation portion extending through the semiconductor substrate and separating the photoelectric conversion region for each pixel. The pixel separation portion includes a first separation wall on a first surface side of the semiconductor substrate and a second separation wall on a second surface side of the semiconductor substrate, the second surface being opposite to the first surface. The first separation wall and the second separation wall have different widths, and regarding the width of the photoelectric conversion region to the second separation wall in a direction perpendicular to a centerline, a first width at the edge center of the pixel is configured to be greater than a second width near the corner of the pixel, the centerline dividing the photoelectric conversion region in two in a horizontal or vertical direction.

[0008] In the first and second aspects of this disclosure, a photoelectric conversion region formed in a semiconductor substrate and a pixel separation portion extending through the semiconductor substrate and separating the photoelectric conversion region for each pixel are provided. The pixel separation portion includes a first separation wall on a first surface side of the semiconductor substrate and a second separation wall on a second surface side of the semiconductor substrate, the second surface being opposite to the first surface. The first separation wall and the second separation wall have different widths, and regarding the width of the photoelectric conversion region to the second separation wall in a direction perpendicular to the centerline, a first width at the edge center of the pixel is configured to be greater than a second width near the corner of the pixel, the centerline dividing the photoelectric conversion region in two in a horizontal or vertical direction.

[0009] Optical detection devices and electronic devices can be standalone devices or modules integrated into other devices. Attached Figure Description

[0010] Figure 1 This is a diagram illustrating a schematic configuration of a solid-state camera device according to an embodiment of the present disclosure. Figure 2 This is a diagram showing an example of the circuit configuration of a pixel. Figure 3 This is a cross-sectional view showing a first structural example of a pixel. Figure 4 This is a plan view of the pixel separation section of a first structural example of a pixel. Figure 5 This is a plan view of the pixel separation section of a modified example of the first structure example of a pixel. Figure 6 This is a diagram illustrating the effect of pixel separation in a first structural example of pixels. Figure 7 This is a diagram used to describe a method for forming the pixel separation portion of a pixel according to the first structural example. Figure 8 This is a diagram used to describe a method for forming the pixel separation portion of a pixel according to the first structural example. Figure 9 This is a diagram used to describe a method for forming the pixel separation portion of a pixel according to the first structural example. Figure 10 This is a cross-sectional view showing a second structural example of a pixel. Figure 11 This is a plan view of the pixel separation section, which is an example of the second structure of a pixel. Figure 12 This is a diagram illustrating the effect of pixel separation in a second structural example of pixels. Figure 13 This is a planar view showing a variation of a pixel. Figure 14 This is a planar view showing a variation of a pixel. Figure 15 This is a planar view showing a variation of a pixel. Figure 16 It is a graph used to describe the migration that occurs within a rectangular pixel. Figure 17 It is a diagram used to describe a repeating array of rectangular pixels. Figure 18 This is a schematic diagram used to describe the staggered arrangement of rectangular pixels. Figure 19 This is a diagram showing other examples of interlaced arrays of pixels. Figure 20 This is a planar diagram used to describe an example of a color filter array for rectangular pixels. Figure 21 This is a planar diagram used to describe an example of a color filter array for rectangular pixels. Figure 22 This is a diagram used to illustrate an example of the use of an image sensor. Figure 23 This is a block diagram illustrating an example configuration of a camera device as an electronic device applying the technology disclosed herein. Figure 24 This is a block diagram illustrating an example of a schematic configuration of a vehicle control system. Figure 25 This is an explanatory diagram showing an example of the installation location of the vehicle exterior information detection unit and the camera unit. Detailed Implementation

[0011] In the following description, modes for implementing the technology of this disclosure (hereinafter referred to as embodiments) will be described with reference to the accompanying drawings. The descriptions will proceed in the following order. 1. Illustrative configuration example of a solid-state camera device 2. Example of Pixel Circuit Configuration 3. Example of the first structure of a pixel 4. Method for forming the pixel separation section in the first structural example 5. Example of a second structure for a pixel 6. Examples of pixel deformation 7. Staggered arrangement of rectangular pixels 8. Examples of Image Sensor Usage 9. Examples of applications of electronic devices 10. Examples of applications involving moving objects

[0012] In the accompanying drawings referenced in the following description, the same or similar reference numerals are used to denote the same or similar parts, and redundant descriptions will be omitted where appropriate. The drawings are schematic, and the relationships between thicknesses and planar dimensions, as well as the ratios of thicknesses of different layers, may differ from actual conditions. Furthermore, the drawings may include parts with different dimensional relationships or ratios between the drawings.

[0013] Furthermore, the definitions of directions such as up and down in the following description are merely for ease of description and do not limit the technical concept of this disclosure. For example, when the target is rotated 90° for observation, up and down is converted and understood as left and right; when the target is rotated 180° for observation, up and down is understood as reversed.

[0014] The technology disclosed herein can be applied to a general light detection device including a pixel array section, in which pixels are arranged in a two-dimensional matrix shape to perform photoelectric conversion on incident light and output a pixel signal corresponding to the amount of light. For example, the technology disclosed herein can be applied to a solid-state imaging device that generates and outputs an image signal based on the amount of incident light, and to a light receiving device (distance measurement sensor) of a distance measurement system that receives infrared light emitted as active light and measures the distance to a subject using a direct ToF method or an indirect ToF method. In the following, examples of the application of the technology disclosed herein to an XY address-type solid-state imaging device (also known as a complementary metal-oxide-semiconductor (CMOS) image sensor) will be described.

[0015] 1. Illustrative configuration example of a solid-state camera device Figure 1 This is a diagram illustrating a schematic configuration of a solid-state camera device according to an embodiment of the present disclosure.

[0016] Figure 1 The solid-state camera device 1 includes a pixel array unit 11 and a peripheral circuit unit. The peripheral circuit unit includes, for example, a vertical drive unit 12, a column processing unit 13, a horizontal drive unit 14, and a system control unit 15.

[0017] The solid-state imaging device 1 also includes a signal processing unit 16 and a data storage unit 17. The signal processing unit 16 and the data storage unit 17 can be mounted on the same substrate as the substrate of the pixel array section 11 and the vertical drive unit 12, or they can be arranged on a different substrate. Furthermore, the signal processing unit 16 and the data storage unit 17 can be located in a semiconductor chip different from the semiconductor chip of the solid-state imaging device 1.

[0018] The pixel array section 11 has the following configuration: a plurality of pixels 21 are arranged in a matrix shape in two dimensions in the row direction and the column direction. Here, the row direction refers to the pixel row in the pixel array section 11, that is, the array direction in the horizontal direction, and the column direction refers to the pixel column in the pixel array section 11, that is, the array direction in the vertical direction.

[0019] Pixel 21 includes a photoelectric conversion unit that generates and accumulates a charge corresponding to the amount of received light, and multiple pixel transistors (so-called MOS transistors). Note that reference will be made below. Figure 2 The following describes a specific circuit configuration example for pixel 21.

[0020] Furthermore, in the pixel array section 11, pixel drive lines 22, which serve as row signal lines, are routed in the row direction for each pixel row, and vertical signal lines 23, which serve as column signal lines, are routed in the column direction for each pixel column. When a signal is read from a pixel 21, the pixel drive lines 22 transmit drive signals for driving. Figure 1 In the diagram, pixel driving line 22 is shown as a single wiring, but it is not limited to a single wiring. One end of pixel driving line 22 is connected to the row-corresponding output terminal of vertical driving unit 12.

[0021] The vertical drive unit 12 is configured with a shift register and an address decoder, and drives each pixel of the pixel array 11 simultaneously for all pixels, row by row. The vertical drive unit 12 and the system control unit 15 together constitute a drive unit that controls the operation of each pixel of the pixel array 11. Although a detailed configuration is omitted from the illustration, the vertical drive unit 12 typically includes two scanning systems: a readout scanning system and a scanout scanning system.

[0022] The readout scanning system selectively scans the pixels 21 of the pixel array 11 row by row to read out signals from the pixels 21. The signals read out from the pixels 21 are analog signals. The scan scan system performs a scan scan on the readout rows that will be scanned by the readout scanning system during an exposure time period earlier than the readout scan.

[0023] The scanning outgoing scan of this scanning system resets the photoelectric conversion units of each pixel 21 by scanning out unnecessary charges from the photoelectric conversion units of the readout rows. Then, by scanning out (resetting) unnecessary charges through the scanning outgoing scan system, a so-called electronic shutter operation is performed. Here, electronic shutter operation refers to the operation of discarding the charges of the photoelectric conversion units and restarting exposure (starting charge accumulation).

[0024] The signal read out by the readout scan system corresponds to the amount of light received immediately after the preceding readout operation or electronic shutter operation. The time interval from the readout timing of the preceding readout operation or the scan timing of the electronic shutter operation to the readout timing of the current readout operation is the exposure time interval of pixel 21.

[0025] The signals output from each pixel 21 of the pixel row selectively scanned by the vertical drive unit 12 are input to the column processing unit 13 via each vertical signal line 23 for each pixel column. The column processing unit 13 performs predetermined signal processing on the signals output from each pixel 21 of the selected row via the vertical signal line 23 for each pixel column of the pixel array section 11, and temporarily holds the processed pixel signals.

[0026] Specifically, as signal processing, the column processing unit 13 performs at least noise removal processing, such as correlated double sampling (CDS) processing. CDS processing removes reset noise and pixel-specific fixed-pattern noise caused by threshold variations in the amplifying transistors within the pixel. In addition to noise removal processing, the column processing unit 13 may also have, for example, analog-to-digital (AD) conversion functionality, and can convert analog pixel signals into digital signals and output digital signals.

[0027] The horizontal drive unit 14 is configured with a shift register and an address decoder, and sequentially selects the unit circuits corresponding to the pixel columns in the column processing unit 13. Through the selective scanning of the horizontal drive unit 14, the pixel signals that have undergone signal processing for each unit circuit in the column processing unit 13 are sequentially output.

[0028] The system control unit 15 is configured with a timing generator that generates various timing signals, and performs drive control of the vertical drive unit 12, column processing unit 13, and horizontal drive unit 14 based on the various timing signals generated by the timing generator.

[0029] The signal processing unit 16 has at least arithmetic processing capabilities and performs various signal processing operations, such as arithmetic processing, on the pixel signals output from the column processing unit 13. When signal processing is performed in the signal processing unit 16, the data storage unit 17 temporarily stores the data required for processing. The pixel signals that have undergone signal processing in the signal processing unit 16 are converted into a predetermined format and output from the output unit 18 to the outside of the device.

[0030] 2. Example of Pixel Circuit Configuration Figure 2 An example of the circuit configuration of each pixel 21 arranged in a matrix shape in the pixel array section 11 is shown.

[0031] like Figure 2 As shown, for example, each pixel 21 has a shared pixel structure, wherein the readout circuit for reading the signal of each pixel is shared by four (2×2) pixels, of which two pixels are arranged in the row direction and two in the column direction.

[0032] Specifically, in the pixel array section 11, the photodiode PD and the transmission transistor TG, which serve as photoelectric conversion sections, are arranged on a pixel-by-pixel basis, and the floating diffusion region FD, the reset transistor RST, the amplification transistor AMP, and the selection transistor SEL are shared and used by four pixels as shared units. Each pixel transistor, such as the transmission transistor TG, the reset transistor RST, the amplification transistor AMP, and the selection transistor SEL, is configured with an N-type MOS transistor (MOS FET) and forms a readout circuit.

[0033] In the attached diagram, the numbers 1 to 4 are added to distinguish the four pixels of the shared readout circuit, such as photodiodes PD1 to PD4 and transmission transistors TG1 to TG4.

[0034] A photodiode (PD) generates and accumulates a charge (signal charge) corresponding to the amount of light received. In a photodiode (PD), the anode terminal is grounded, and the cathode terminal is connected to the floating diffusion region (FD) via a transfer transistor (TG).

[0035] When the transfer transistor TG is turned on by the transfer drive signal provided to the gate electrode, the charge generated by the photodiode PD is read out and transferred to the floating diffusion region FD. The floating diffusion region FD holds the charge read out from at least one of the four photodiodes PD.

[0036] When the reset transistor RST is turned on by the reset drive signal provided to the gate electrode, the charge accumulated in the floating diffusion region FD is discharged to the drain (supply voltage VDD), and the potential of the floating diffusion region FD is reset.

[0037] The amplifying transistor AMP outputs a signal corresponding to the potential of the floating diffusion region FD. That is, the amplifying transistor AMP and the load MOS transistor (not shown) connected via vertical signal line 23 as a constant current source form a source follower circuit, and the signal VSL indicating the level corresponding to the charge accumulated in the floating diffusion region FD is output from the amplifying transistor AMP to the column processing unit 13 via the selection transistor SEL. Figure 1 ).

[0038] When a shared unit is selected via the selection drive signal provided to the gate electrode, the selection transistor SEL is turned on, and the signal VSL generated in each pixel 21 of the shared unit is output to the column processing unit 13 via the vertical signal line 23. The transmission drive signal, selection drive signal, and reset drive signal are transmitted via... Figure 1 The pixel driving line 22 is provided from the vertical driving unit 12.

[0039] As described above, the four (2×2) pixels 21, which are shared units, share and use individual pixel transistors such as the reset transistor RST, the amplification transistor AMP, and the selection transistor SEL.

[0040] For example, the solid-state camera device 1 can appropriately select and execute drives such as the following drives according to the operating mode.

[0041] For example, as a first operating mode, the solid-state camera device 1 may have the following mode: the four transmission transistors TG of the four pixels as a shared unit are turned on sequentially in units of one pixel, and the charge generated in the photodiode PD of one pixel is transferred to the floating diffusion region FD and output as a signal VSL to the column processing unit 13 via the vertical signal line 23.

[0042] For example, as a second operating mode, the solid-state camera device 1 may have the following mode: in four pixels that are shared units, the transmission transistor TG is turned on in units of two adjacent pixels in the row direction or column direction, and the charge generated in the photodiode PD of the two pixels is simultaneously transferred to the floating diffusion region FD and output as a signal VSL to the column processing unit 13 via the vertical signal line 23.

[0043] For example, as a third operating mode, the solid-state camera device 1 may have the following mode: the transmission transistors TG of all four pixels as shared units are turned on simultaneously, and the charges generated in the photodiodes PD of the four pixels are simultaneously transferred to the floating diffusion region FD and output as a signal VSL to the column processing unit 13 via the vertical signal line 23.

[0044] Note that the shared unit of the readout circuit for pixel 21 is not limited to four pixels. For example, a circuit configuration of eight (4×2) pixels or eight (2×4) pixels sharing the readout circuit can be used. Of course, pixel 21 can also be configured so that pixel 21 does not share the readout circuit, and the readout circuit is set separately for each pixel unit.

[0045] 3. Example of the first structure of a pixel Figure 3 This is a cross-sectional view showing a first structural example of pixel 21.

[0046] The following description of pixel 21 will use a back-illuminated case as an example, but this technique can also be applied to front-illuminated cases.

[0047] For example, Figure 3 The pixel 21 shown is formed in a semiconductor substrate 51 using silicon (Si) as the semiconductor material. Figure 3 In the diagram, the upper first surface 51a of the semiconductor substrate 51 is the front side of the semiconductor substrate 51. Pixel transistors such as the transmission transistor TG, the amplification transistor AMP, and the reset transistor RST, as well as a multilayer wiring layer, are formed on the first surface 51a, but their illustrations are omitted. The multilayer wiring layer is a layer comprising one or more wiring layers made of a metal material such as copper (Cu), tungsten (W), or aluminum (Al) and an interlayer insulating film made of a silicon oxide film, etc. On the other hand, the lower second surface 51b of the semiconductor substrate 51 is the back side of the semiconductor substrate 51 and is the light incident surface.

[0048] In the semiconductor substrate 51, a P-type semiconductor region 61 is formed on the first surface 51a side and an N-type semiconductor region 62 is formed on the second surface 51b side for each pixel, and a photodiode PD utilizing the PN junction formed by the P-type semiconductor region 61 and the N-type semiconductor region 62 is formed. The P-type semiconductor region 61 and the N-type semiconductor region 62 are part of the photoelectric conversion region of the pixel 21.

[0049] Furthermore, a pixel separation section 71 is formed in the boundary between adjacent pixels 21 on the semiconductor substrate 51. This pixel separation section 71 separates the photoelectric conversion area formed for each pixel on a pixel-by-pixel basis. The pixel separation section 71 is composed of a first separation wall 71a and a second separation wall 71b with different widths, and extends through the semiconductor substrate 51, thereby completely separating the photoelectric conversion area formed for each pixel. Specifically, the width of the first separation wall 71a on the front side of the semiconductor substrate 51 is formed to be greater than the width of the second separation wall 71b on the back side (width of the first separation wall 71a > width of the second separation wall 71b). The first separation wall 71a is configured by embedding a sidewall 72 and an insulating film 73, and the second separation wall 71b is configured by embedding only the insulating film 73. The sidewall 72 is formed of an oxide film (SiO2), a nitride film (SiN), or a laminate thereof. The insulating film 73 is formed of, for example, SiO2, SiN, undoped polysilicon, or Al2O3.

[0050] On the sidewall of the second separation wall 71b, a P-type semiconductor region 74 and an N-type semiconductor region 75 are sequentially formed toward the center (inside) of the pixel 21. The P-type semiconductor region 74 and the N-type semiconductor region 75 are also part of the photoelectric conversion region of the pixel 21. The N-type semiconductor region 62 and the N-type semiconductor region 75 have different impurity concentrations, and the N-type semiconductor region 75 is a region with a concentration higher than that of the N-type semiconductor region 62. The P-type semiconductor region 74 is formed at a high concentration along the sidewall of the second separation wall 71b, thereby suppressing electrons from the interface of the second separation wall 71b. In addition, by forming a high-concentration N-type semiconductor region 75 inside (pixel center side) the high-concentration P-type semiconductor region 74, the saturation charge amount Qs can be increased. The P-type semiconductor region 74 and the N-type semiconductor region 75 are formed by, for example, conformal doping. Conformal doping is a method for forming impurity regions, including, for example, solid-phase diffusion method and plasma doping method, etc.

[0051] A planarization film 81 is formed on the second surface 51b which is the light incident surface of the semiconductor substrate 51. A light-shielding film 82 is formed in the pixel boundary portion within the planarization film 81. The light-shielding film 82 is provided to prevent light leakage into adjacent pixels 21. For example, the light-shielding film 82 is made of a metal material such as tungsten (W).

[0052] An on-chip lens (OCL) 83 for converging incident light on the photodiode PD is formed outside the planarization film 81. The OCL 83 can be formed of an inorganic material. For example, SiN, SiO or SiO can be used. x N y (where 0 < x ≤ 1 and 0 < y ≤ 1).

[0053] Although not shown in Figure 3 , a configuration in which a cover glass or a transparent plate made of resin or the like is bonded to the OCL 83 can be adopted. In addition, although not shown in Figure 3 , a configuration in which a color filter layer is formed between the OCL 83 and the planarization film 81 can be adopted. In the case of forming a color filter layer, the color filter array can be arranged, for example, in a Bayer array obtained by arranging red (R), green (G), green (G) and blue (B) color filters in four (2×2) pixels, or can be arranged in a Quad Bayer array obtained by arranging each of the R, G, G and B color filters in a Bayer array in units of four (2×2) pixels. In the Quad Bayer array, the arrangement unit of a color filter is four (2×2) pixels.

[0054] As described above, pixel 21 includes a pixel separation portion 71, which is composed of a first separation wall 71a and a second separation wall 71b formed with different widths according to their depth positions in the semiconductor substrate 51. The first separation wall 71a and the second separation wall 71b are configured with different planar shapes.

[0055] Figure 4 It is a plan view schematically showing the planar shapes of the first separation wall 71a and the second separation wall 71b.

[0056] Figure 4 The first separating wall 71a' in the middle represents in Figure 3 The boundary between the first separation wall 71a and the N-type semiconductor region 62 at line X-X'. Figure 4 The second separation wall 71b' in the middle represents the second separation wall 71b' in the middle. Figure 3 The boundary between the second separation wall 71b and the P-type semiconductor region 74 at line Y-Y'.

[0057] The first separation wall 71a' is the boundary between the pixel separation section 71 and the photoelectric conversion region on the first surface 51a side, which is the front side of the semiconductor substrate 51, and the second separation wall 71b' is the boundary between the pixel separation section 71 and the photoelectric conversion region on the second surface 51b side, which is the back side of the semiconductor substrate 51. Therefore, the pixel 21 is formed such that the planar shape of the pixel separation section 71 is configured to be different when viewed from the front side of the semiconductor substrate 51 and when viewed from the back side.

[0058] Except for the corners of the photoelectric conversion region, the first separation wall 71a' is formed in a straight line and has a generally rectangular planar shape. On the other hand, the second separation wall 71b' has a generally circular planar shape. The distance DSa between the first separation walls 71a' of adjacent pixels 21 is greater than (wider than) the distance DSb between the second separation walls 71b'. Although the manufacturing method of the pixel separation section 71 will be described below, this difference in planar shape occurs due to the presence or absence of the sidewalls 72 during the manufacturing process and the migration of the semiconductor layer (Si) when hydrogen baking (H2 baking) is performed.

[0059] Assume the centerline 101h is defined in the horizontal direction ( Figure 4 The line that divides the photoelectric conversion area of ​​pixel 21 in two along the left-right direction is as follows: When comparing the width HUa of the photoelectric conversion area to the first separation wall 71a' in the direction perpendicular to the center line 101h at the center of the edge and near the corner, the first width HUa1 to the first separation wall 71a' at the center of the edge and the second width HUa2 to the first separation wall 71a' at the near corner are basically the same (first width HUa1 = second width HUa2).

[0060] On the other hand, when comparing the width HLb of the photoelectric conversion region to the second separation wall 71b' in the direction perpendicular to the center line 101h at the edge center and near the corner of pixel 21, the first width HLb1 to the second separation wall 71b' at the edge center is greater than the second width HLb2 to the second separation wall 71b' near the corner (first width HLb1 > second width HLb2). When comparing the first width HUa1 to the first separation wall 71a' and the first width HLb1 to the second separation wall 71b' at the edge center of the photoelectric conversion region, the first width HLb1 to the second separation wall 71b' at the edge center is greater than the first width HUa1 to the first separation wall 71a' (first width HLb1 > first width HUa1). The width HLb of the photoelectric conversion region in the direction perpendicular to the center line 101h gradually decreases from the edge center of the photoelectric conversion region toward the corner (first width HLb1 → second width HLb2). When comparing the second width HUa2 to the first separation wall 71a' and the second width HLb2 to the second separation wall 71b' near the corner of the photoelectric conversion region, the second width HLb2 to the second separation wall 71b' is less than the second width HUa2 to the first separation wall 71a' (second width HLb2 < second width HUa2).

[0061] Assume the centerline 101v is defined in the vertical direction ( Figure 4 The line that divides the photoelectric conversion region in two along the vertical direction (in the center line 101v) can be used to similarly describe the relationship between the widths of the photoelectric conversion region at its center and near its corners in the direction perpendicular to the center line 101v. That is, when comparing the width VUa of the photoelectric conversion region from the center to the first separating wall 71a' in the direction perpendicular to the center line 101v at the center and near its corners, the first width VUa1 at the center and the second width VUa2 at the corner are essentially the same (first width VUa1 = second width VUa2).

[0062] On the other hand, when comparing the width VLb of the photoelectric conversion region to the second separation wall 71b' in the direction perpendicular to the center line 101v at the center of the photoelectric conversion region and near the corner, the first width VLb1 to the second separation wall 71b' at the center of the side is greater than the second width VLb2 to the second separation wall 71b' near the corner (first width VLb1 > second width VLb2). When comparing the first width VUa1 to the first separation wall 71a' and the first width VLb1 to the second separation wall 71b' at the center of the side of the photoelectric conversion region, the first width VLb1 to the second separation wall 71b' is greater than the first width VUa1 to the first separation wall 71a' (first width VLb1 > first width VUa1). The width VLb of the photoelectric conversion region in the direction perpendicular to the center line 101v gradually decreases from the center of the side of the photoelectric conversion region toward the corner (first width VLb1 → second width VLb2). When comparing the second width VUa2 to the first separation wall 71a' and the second width VLb2 to the second separation wall 71b' near the corner of the photoelectric conversion region, the second width VUa2 to the first separation wall 71a' is greater than the second width VLb2 to the second separation wall 71b' (second width VUa2 > second width VLb2).

[0063] Figure 5 A variation of the first structural example of pixel 21 is shown, and it is similar to... Figure 4 , Figure 5 It is a plan view schematically showing the planar shapes of the first separation wall 71a and the second separation wall 71b.

[0064] Depending on the conditions at the time of manufacture, such as Figure 5 As shown, the planar shape of the second separating wall 71b' can be closer to an approximately octagonal shape than an approximately circular shape. In this case, similarly, the widths HUa (HUa1 and HUa2), HUb (HUb1 and HUb2), VUa (VUa1 and VUa2), and VUb (VUb1 and VUb2) based on the center line 101h or 101v that vertically or horizontally divides the photoelectric conversion region in two have the above-described relationships. As the photoelectric conversion region moves from the center of its edge towards the corner (first width HLb1 → second width HLb2), the width HLb of the photoelectric conversion region in the direction perpendicular to the center line 101h is equal to or less than the width of the center of its edge. As the photoelectric conversion region moves from the center of its edge towards the corner (first width VLb1 → second width VLb2), the width VLb of the photoelectric conversion region in the direction perpendicular to the center line 101v is equal to or less than the width of the center of its edge.

[0065] As described above, in the pixel 21 according to the first structure example, the planar shape of the pixel separation portion 71, which is the photoelectric conversion region that completely separates each pixel, is such that the first separation wall 71a, which is close to the first surface 51a, which is the front side of the semiconductor substrate 51, has a generally rectangular planar shape, while the second separation wall 71b, which is located deeper than the first separation wall 71a, has a generally circular or generally octagonal planar shape.

[0066] Now refer to Figure 6 This describes the effect of the second separation wall 71b having a planar shape that is not approximately rectangular but approximately circular.

[0067] Figure 6 Figure A shows a plan view and potential diagram of the photoelectric conversion region in the case that the photoelectric conversion region separated by the second separation wall 71b of the pixel separation section 71 is formed into a rectangular shape.

[0068] Figure 6 Figure B shows a plan view and a potential diagram of the photoelectric conversion region when the photoelectric conversion region separated by the second separation wall 71b of the pixel separation section 71 is formed into a circular shape.

[0069] P-type semiconductor region 74 and N-type semiconductor region 75 are formed along the second separation wall 71b through conformal doping. When P-type semiconductor region 74 and N-type semiconductor region 75 are formed through conformal doping, Figure 6 At the corner of the photoelectric conversion region in A, doping is performed both horizontally from the second separation wall 71b and vertically. Therefore, when comparing the potential 121X indicated by arrow 121X from the corner towards the pixel center... p and the potential 121Y indicated by arrow 121Y in the direction from the edge center towards the pixel center. p At that time, a region with deep potential is formed at the corner. Due to potential 121X p and potential 121Y p The differences make it difficult to design charge transport.

[0070] In contrast, the photoelectric conversion region is formed as follows Figure 6 In the case of a circular shape in B, conformal doping is uniformly performed from the second separation wall 71b on all sidewalls, thus the potential 121X from the corner toward the pixel center direction. p and the potential 121Y from the center of the edge towards the center of the pixel p It is uniform. Because the potential is 121X p and potential 121Y p It is uniform, so it is easy to design the charge transfer, which helps to design a relatively increased saturation charge Qs for pixel 21.

[0071] As described above, in pixel 21 of the first structural example, the first separation wall 71a, which is near the front side of the semiconductor substrate 51, has a generally rectangular planar shape as the planar shape of the pixel separation portion 71, while the second separation wall 71b, located deeper than the first separation wall 71a, has a generally circular or generally octagonal planar shape, which improves charge transport within the photoelectric conversion region. On the other hand, in order to form the transport transistor TG and the floating diffusion region FD, a straight shape is preferred on the front side of the semiconductor substrate 51, and the planar shape of the first separation wall 71a is generally rectangular, which is therefore suitable.

[0072] 4. Method for forming the pixel separation section in the first structural example Now refer to Figures 7 to 9 The method for forming the pixel separation portion 71 of pixel 21 according to the first structure example is described. Figure 7 and Figure 8 A cross-sectional view is shown when three pixel separation portions 71 are arranged in the horizontal or vertical direction of the pixel array portion 11.

[0073] First, such as Figure 7 As shown in Figure A, a hard mask 201, made of SiN or SiO2, is formed in a predetermined area of ​​the first surface 51a, which is the front side of the semiconductor substrate 51. The area where the hard mask 201 is formed is the area other than the area where the first separation wall 71a of the pixel separation portion 71 is formed. Then, a portion of the semiconductor substrate 51 is removed by dry etching based on the hard mask 201, and a trench 202 with a depth corresponding to the first separation wall 71a is formed. The planar shape of the trench 202 is a lattice shape along the pixel boundary.

[0074] Subsequently, as Figure 7 As shown in B, a sidewall 72 is formed on the sidewall of trench 202. The sidewall 72 can be formed by, for example, stacking oxide films or nitride films using chemical vapor deposition (CVD) or atomic layer deposition (ALD), and then etching back the oxide films or nitride films using reactive ion etching (RIE).

[0075] Subsequently, as Figure 7 As shown in Figure C, dry etching is performed using a hard mask 201 and sidewall 72 as masks to form a trench 203 with a depth corresponding to the second separation wall 71b. The planar shape of the trench 203 is as follows: Figure 9 As shown in A.

[0076] Subsequently, as Figure 7As shown in Figure D, an N-type semiconductor region 75 is formed in the sidewalls of trench 203 by conformal doping with an N-type impurity such as phosphorus (P). As a conformal doping method, for example, solid-state diffusion or plasma doping can be used.

[0077] Subsequently, as Figure 8 As shown in Figure A, in-situ hydrogen baking (H2 baking) is performed. Through hydrogen baking, the silicon layer of the semiconductor substrate 51 near the sidewalls of trench 203 not covered by sidewall 72 migrates, and the planar shape of trench 203, which becomes the second separation wall 71b located deeper from the front side of the semiconductor substrate 51, changes as shown in Figure A. Figure 9 The planar shape, roughly circular or roughly octagonal, is shown by the dashed line in B. If the hydrogen baking process is insufficient, streak defects will occur at the interface between the silicon layer of the semiconductor substrate 51 and the silicon layer 221 formed by epitaxial growth in the next process due to residual native oxide film and other factors, which leads to deterioration of dark properties.

[0078] Subsequently, as Figure 8 As shown in Figure B, a silicon layer 221 is formed on the sidewalls of trench 203 by epitaxial growth. Conformal doping using a P-type impurity such as boron (B) is performed on the silicon layer 221, thereby achieving... Figure 8 As shown in Figure C, a P-type semiconductor region 74 is formed in the sidewall of trench 203.

[0079] Finally, as Figure 8 As shown in Figure D, an insulating film 73, such as SiO2 or SiN, is embedded in the trench 203 to form the first separation wall 71a and the second separation wall 71b constituting the pixel separation section 71. Subsequently, the second surface 51b, which is the back side of the semiconductor substrate 51, is thinned to a thickness that exposes the second separation wall 71b.

[0080] The pixel separation section 71 in the first structural example can be formed as described above.

[0081] 5. Example of a second structure for a pixel Figure 10 This is a cross-sectional view showing a second structural example of pixel 21.

[0082] exist Figure 10 In the figures, the same reference numerals are used to denote the same figures as those in the figures below. Figure 3 In the first structural example shown, the same parts will be omitted from the description, and the different parts will be described.

[0083] Figure 10The second structural example differs from the first structural example in that a conductive material 241, instead of an insulating film 73, is embedded in the center of the first separation wall 71a and the second separation wall 71b constituting the pixel separation portion 71, and a predetermined bias voltage (e.g., a negative bias voltage) is applied to the conductive material 241. All other aspects are the same as in the first structural example. The conductive material 241 is formed of, for example, polysilicon, doped polysilicon doped with N-type or P-type impurities, or a transparent electrode such as indium tin oxide (ITO) or ZnO. The conductive material 241 is embedded as part of the pixel separation portion 71, and a predetermined bias voltage (e.g., a negative bias voltage) is applied to the conductive material 241, thereby enhancing the pinning at the sidewalls of the pixel separation portion 71 and improving dark characteristics.

[0084] Note that, although in Figure 10 In the second separation wall 71b, no insulating film 73 is formed between the conductive material 241 and the P-type semiconductor region 74, but an insulating film 73 can be formed similarly to that of the first separation wall 71a. In this case, the second separation wall 71b is configured by embedding the conductive material 241 in the central portion sandwiched by the insulating film 73 in the plan view.

[0085] Figure 11 This is a plan view schematically showing the planar shape of the conductive material 241, which is part of the pixel separation section 71.

[0086] exist Figure 10 The conductive material 241 in the first separation wall 71a at line X-X' has a generally rectangular planar shape as shown by the solid line. Figure 10 The conductive material 241 in the second separation wall 71b at line Y-Y' has a generally circular planar shape as shown by the dashed line.

[0087] Now refer to Figure 12 The effect is described when the conductive material 241 is embedded as part of the pixel separation part 71, and the planar shape of the second separation wall 71b is formed into a roughly circular shape.

[0088] Assuming the planar shape of the conductive material 241 in the pixel separation section 71 is formed as follows Figure 12 In the case of the rectangular shape shown in Figure A, the electric field from the conductive material 241, which is subjected to a negative bias, is generated from both the horizontal and vertical sides (sidewalls). This causes the electric field to concentrate in the corners of the photoelectric conversion region, resulting in reliability drawbacks such as deterioration of time-dependent dielectric breakdown (TDDB) lifetime. Figure 12As shown in B, since the electric field generated by the conductive material 241 is uniform when the planar shape of the conductive material 241 is formed into a circular shape, the electric field concentration is reduced and the withstand voltage is improved by making the planar shape close to a circular shape. Therefore, by forming the planar shape of the conductive material 241, which is part of the pixel separation section 71, into a roughly circular or roughly octagonal shape, the reliability of the solid-state imaging device 1 can be improved.

[0089] As described above, according to the second structural example, pixel 21 can improve reliability in addition to improving charge transport in the photoelectric conversion region as in the first structural example.

[0090] 6. Examples of pixel deformation Figure 13 This is a plan view showing a modified example of pixel 21.

[0091] The first and second structural examples of pixel 21 described above are examples where the planar shape of the photodiode PD, which serves as the photoelectric conversion region, is as follows: Figure 13 The pixel structure shown in Figure A is a square shape.

[0092] However, the structure of the pixel separation section 71 described above is also applicable to the planar shape of the photodiode PD, which serves as the photoelectric conversion region, as shown in the description. Figure 13 The rectangular pixel structure shown in B and C.

[0093] Figure 13 B and C show the following structure: the planar shape of the photodiode PD is rectangular, and an overflow path 301 is formed between the two photodiodes PD arranged in the left-right direction. Figure 13 B corresponds to the pixel separation section 71 in the first structural example in which the periphery of the photodiode PD is composed of an insulating film 73, and Figure 13 C corresponds to the pixel separation section 71 in the second structural example in which a conductive material 241 is formed on the periphery of the photodiode PD.

[0094] In a pixel structure where the planar shape of the photodiode PD is rectangular and the overflow path 301 is formed between two photodiodes PDs arranged in the left-right direction, such as... Figure 14 As shown, each pixel 21 has a rectangular planar shape, and is formed by two adjacent pixel regions in the row direction to form a square shape. Then, an on-chip lens 311 is arranged for the two pixels with square shapes. In each pixel 21, the floating diffusion region FD is shared by four (2×2) pixels, and the floating diffusion region FD is arranged in the center of the four pixel regions constituting the shared unit. The transmission transistors TG (TG1, TG2, TG3, and TG4) of each pixel 21 are arranged near the floating diffusion region FD.

[0095] In such a pixel configuration example, when the vertical drive unit 12 of the solid-state imaging device 1 outputs signals from two pixels sharing an on-chip lens 311 on a per-pixel basis, for example, the R pixel signal received by the pixel 21 (R pixel) to the right of the on-chip lens 311 and the L pixel signal received by the pixel 21 (L pixel) to the left of the on-chip lens 311 have a phase difference, and can therefore be used as a phase difference signal. On the other hand, when the phase difference is not detected and the signal is used as the signal for the captured image, the transmission transistors TG of the two pixels sharing the on-chip lens 311 are simultaneously turned on.

[0096] An overflow path 301 is formed between photodiodes PDs of two pixels sharing an on-chip lens 311. The overflow path 301 separates the left pixel 21 and the right pixel 21 from each other with a predetermined barrier (separation potential). Before the signal charge reaches the barrier height of the overflow path 301, the signal charge of the left pixel 21 and the right pixel 21 accumulates independently in their respective photodiodes PDs. When the signal charge exceeds the barrier height of the overflow path 301, the signal charge flows from one of the two photodiodes PDs to the other via the overflow path 301. Figure 15 As shown in A and B, the overflow path 301 formed between the photodiodes PD of the two pixels can be set at the end (top or bottom) of the long side, instead of as shown in Figures A and B. Figure 13 At the center of the long side shown. Figure 15 An example is shown below: overflow path 301 is placed at a symmetrical position in two pixels that are perpendicular to each other, but overflow paths can also be placed at the same position at the top or bottom of the long side in each pixel.

[0097] 7. Staggered arrangement of rectangular pixels In the following text, such as Figures 13 to 15 One of the pixels shown has a rectangular planar shape, and the pixel 21 formed by two pixel regions including the overflow path 301 to form a square shape is called rectangular pixel 21. Furthermore, it shares an on-chip lens 311 ( Figure 14 Two rectangular pixels (21) are called square unit pixels.

[0098] In rectangular pixel 21, when migration of the semiconductor layer (Si) occurs, the photoelectric conversion region with a rectangular shape is as follows: Figure 16The changes are as shown. That is, the photoelectric conversion region expands due to migration, thereby reducing the size of the recess between the two photodiodes (PDs), and also expanding the area of ​​the overflow path 301. In the rectangular photoelectric conversion region, the side facing outwards along the longer side expands more, while the side facing outwards along the shorter side expands less. Note that migration refers to the phenomenon where the semiconductor layer (Si) changes due to the heat from the hydrogen baking process, resulting in a decrease in the surface area of ​​the sidewalls while maintaining the volume of the photoelectric conversion region of the photodiode (PD) constant.

[0099] When the photoelectric conversion area of ​​rectangular pixel 21 expands in the left-right direction due to migration, the photoelectric conversion area of ​​the square unit pixel composed of two rectangular pixels 21 becomes nearly circular, thus having a near-circular shape. Figure 14 The shape of the on-chip lens 311 shown facilitates the convergence of incident light. Furthermore, as the photoelectric conversion region of the rectangular pixel 21 expands in the left-right direction, the distance from the overflow path 301 to the center portion of the photoelectric conversion region of the rectangular pixel 21 increases, reducing the influence of P-type ion diffusion during P-type ion implantation to form the separation potential of the overflow path 301. This facilitates the transmission design of the photodiode PD. Additionally, the corner of the photoelectric conversion region of the rectangular pixel 21 near the overflow path 301 moves in the direction of the expansion of the recess due to migration, thereby facilitating pixel separation of the two photodiodes PDs outside the overflow path 301.

[0100] On the other hand, when migration occurs, the long side of the photoelectric conversion region of the photodiode (PD) bulges outward, therefore, as Figure 17 As shown, in a pixel array in which rectangular pixels 21 are repeatedly arranged along the row and column directions in the pixel array section 11, adjacent pixel separation sections 71 in the left-right direction (row direction) are separated by a pixel separation section 71. Figure 17 The linewidth (not shown) is reduced as in region 321 surrounded by solid lines. To ensure pixel region separation, when the linewidth of adjacent pixel separation portions 71 in the left-right direction is expected to decrease and the linewidth of the pixel separation portion 71 is pre-formed to be larger (wider), the volume of the photoelectric conversion region of each pixel decreases, thereby reducing the saturation charge Qs. Conversely, in the intersections of the pixel separation portions 71, such as region 322, the linewidth of the pixel separation portion 71 increases, making it difficult to embed the insulating film 73 or conductive material 241 to be embedded into the pixel separation portion 71.

[0101] Therefore, when the pixel structure of the pixel array section 11 is a rectangular pixel 21, such as Figure 18As shown, the solid-state imaging device 1 is configured by arranging square unit pixels in an interleaved manner, in which the pixel position of the square unit pixel is offset from the adjacent square unit pixel of another pixel column by half the pixel size in the column direction. Therefore, as shown in region 341, the arrangement is such that in adjacent first and second pixel columns, the protruding long side of the photoelectric conversion region of the photodiode PD of a rectangular pixel 21 in one first pixel column is close to the concave corner of the photoelectric conversion region of the photodiode PD of a rectangular pixel 21 in another second pixel column, so that the photodiode PD of the rectangular pixel 21 can be efficiently arranged throughout the entire pixel array 11. Figure 18 In the interlaced array of rectangular pixels 21, with Figure 17 Compared to the repeating array of rectangular pixel matrix 21 shown, with the same pixel size, the saturation charge Qs can be increased by increasing the volume of the photoelectric conversion region of the photodiode PD. When the volume of the photoelectric conversion region of the photodiode PD is the same, comparison... Figure 18 interlaced array and Figure 17 Repeating array, Figure 18 The pixel spacing in the staggered array can be smaller, thus allowing for finer pixels. Furthermore, defects such as those in the pixel separation section 71 can be eliminated. Figure 17 The linewidth extension of region 322 and other areas can also improve problems related to material embedding.

[0102] Figure 19 This is a diagram showing other examples of interlaced arrays of pixels.

[0103] Figure 19 A is another example where square unit pixels are arranged in an alternating pattern. Figure 19 In A, the long side of the rectangular pixel 21 is parallel to the row direction, and the two rectangular pixels 21 that constitute the square unit pixel are arranged in the vertical direction (column direction) rather than the horizontal direction (row direction). Furthermore, the square unit pixels are arranged by offsetting the pixel position of the square unit pixel from the vertically adjacent square unit pixel of another pixel row by half the pixel size in the row direction.

[0104] Figure 19 B shows that it has Figure 13 The example shown in A illustrates a square pixel structure in which pixels 21 are arranged in an interleaved manner, in which the pixel position of pixel 21 is offset from the pixel 21 of another adjacent pixel column by half the pixel size in the column direction.

[0105] Figure 19 C shows that it has Figure 13The example shown in A illustrates a square pixel structure in which pixels 21 are arranged in an interleaved manner, in which the pixel position of a pixel is offset from the pixel 21 of another adjacent pixel row by half the pixel size in the row direction.

[0106] Figure 19 The D is shown in the following example: having Figure 13 The square pixel structure shown in A is rotated 45 degrees relative to the row and column directions and arranged in a 45-degree tilt direction, which is called the ClearVid array. The pixel positions are offset by half the pixel size relative to the pixel 21 of another adjacent pixel column in the 45-degree tilt direction.

[0107] Figure 20 and Figure 21 This is a diagram illustrating an example of a color filter array where color filters are arranged for rectangular pixels 21.

[0108] Figure 20 The rectangular pixel 21 is shown in the figure. Figure 18 The example shown is a color filter array arranged in an alternating pattern.

[0109] For example, in rectangle pixel 21 Figure 18 In the case of an alternating arrangement, such as Figure 20 As shown, color filters 341R, 341G, and 341B can be arranged similarly to the color filter array in a cellular array configuration. Specifically, one of the even-numbered or odd-numbered columns of square unit pixels is a column containing only the green (G) color filter 341G, and the other is a column alternating between green (G) color filters 341G and red (R) color filters 341R, or alternating between blue (B) color filters 341B and green (G) color filters 341G. The blue color filter 341B and the red color filter 341R are surrounded by square unit pixels containing the green color filter 341G. The columns containing the blue color filter 341B and the columns containing the red color filter 341R are arranged such that they sandwich the columns containing only the green color filter 341G.

[0110] Figure 21 An example of a color filter array with a four-Bayer array is shown.

[0111] Figure 21 The four Bayer array in the image is a color filter array as follows: green filter 341G, red filter 341R, and blue filter 341B are arranged in a Bayer array, and the arrangement unit of the color filters for each color is a 2×2 square unit pixel. For example, the color filter array in rectangular pixel 21 is as follows. Figure 21In the case of the quad Bayer array shown, square unit pixels including color filters 341 of the same color are arranged such that the direction of the rectangular pixel 21 in which the blue color filter 341B is arranged and the direction of the rectangular pixel 21 in which the red color filter 341R is arranged are orthogonal to the direction of the rectangular pixel 21 in which the green color filter 341G is arranged.

[0112] Notice, Figure 20 and Figure 21 This is a diagram used to describe the arrangement of color filters 341R, 341G, and 341B, and... Figure 20 and Figure 21 In the diagram, color filters 341R, 341G, and 341B are only shown inside the photodiode PD. However, in reality, color filters 341R, 341G, and 341B are formed to cover the entire pixel area.

[0113] As a color filter array, filters of complementary colors such as yellow, magenta, and cyan can be arranged instead of filters of the three primary colors R, G, and B mentioned above.

[0114] Method for forming the staggered arrangement of rectangular pixels Method and reference for forming rectangular pixels 21 by staggered arrangement Figures 7 to 9 The pixel separation portion 71 of pixel 21 described in the first structure example is formed in the same way. In short, Figure 7 The pattern of the hard mask 201 in A is a pattern that matches the staggered arrangement of the rectangular pixels 21. Then, through Figure 8 As shown in Figure A, the hydrogen baking process causes the silicon layer of the semiconductor substrate 51 to migrate, and the planar shape of the trench 203, located at a deeper portion from the front side of the semiconductor substrate 51, changes. Figure 16 The shape shown on the right. Next, as... Figure 8 As shown in Figure B, a silicon layer 221 is formed on the sidewalls of trench 203 by epitaxial growth, and a P-type semiconductor region 74 is formed in the sidewalls of trench 203 by conformal doping using a P-type impurity. This configuration is an example of the case where the signal charge is electrons. However, when the signal charge is holes, conformal doping using an N-type impurity is performed on the silicon layer 221 formed by epitaxial growth. Without forming the P-type semiconductor region 74, the epitaxial growth process and the conformal doping process are omitted.

[0115] 8. Examples of Image Sensor Usage Figure 22 This is a diagram showing an example of using the image sensor of the solid-state camera device 1 described above.

[0116] The solid-state camera device 1 described above can be used as an image sensor in various situations where it senses light such as visible light, infrared light, ultraviolet light, and X-rays, as described below.

[0117] • Devices used for taking images for appreciation, such as digital cameras and portable devices with camera functions. • Equipment used for transportation purposes, such as: in-vehicle sensors that capture images of the front, rear, surroundings, and interior of a car for safe driving purposes such as automatic parking and driver status recognition; surveillance cameras used to monitor moving vehicles or roads; and distance measuring sensors for measuring distances between vehicles, etc. • Devices used in home appliances such as televisions, refrigerators, and air conditioners to capture images of user gestures and thus operate the device based on those gestures. • Devices used for healthcare purposes, such as endoscopes and devices that perform angiography by receiving infrared light, etc. • Security equipment, such as surveillance cameras for crime prevention and cameras for personnel authentication. • Devices used in beauty treatments, such as dermatographs for photographing the skin and microscopes for photographing the scalp. • Devices for sports, such as action cameras and wearable cameras for sports applications. • Equipment used in agriculture, such as cameras used to monitor the condition of fields or crops.

[0118] 9. Examples of applications of electronic devices The technology disclosed herein is not limited to solid-state imaging devices. That is, the technology disclosed herein is applicable to general electronic devices that use solid-state imaging devices in their image capturing unit (photoelectric conversion unit), such as imaging devices like digital still cameras or video cameras, portable terminal devices with imaging capabilities, or copiers that use solid-state imaging devices in their image reading units. The solid-state imaging device can be formed as a chip or as a module with imaging capabilities, with the imaging unit and signal processing unit or optical system jointly packaged within the module.

[0119] Figure 23 This is a block diagram illustrating an example configuration of a camera device as an electronic device applying the technology disclosed herein.

[0120] Figure 23 The imaging device 600 includes an optical unit 601, a solid-state imaging device (camera device) 602, and a digital signal processor (DSP) circuit 603. The optical unit 601 includes a lens group, etc., and the solid-state imaging device 602 employs... Figure 1The solid-state camera device 1 is configured in the image, and the DSP circuit 603 is a camera signal processing circuit. The camera device 600 also includes a frame memory 604, a display unit 605, a recording unit 606, an operation unit 607, and a power supply unit 608. The DSP circuit 603, frame memory 604, display unit 605, recording unit 606, operation unit 607, and power supply unit 608 are connected to each other via a bus 609.

[0121] The optical unit 601 captures incident light (image light) from the subject and images it on the imaging surface of the solid-state imaging device 602. The solid-state imaging device 602 converts the amount of incident light imaged on the imaging surface by the optical unit 601 into an electrical signal in pixels and outputs this electrical signal as a pixel signal. The solid-state imaging device 602 uses... Figure 1 The solid-state imaging device 1, namely, the pixel separation section 71 has a generally rectangular planar shape in the first separation wall 71a near the front side of the semiconductor substrate 51, and a generally circular or generally octagonal planar shape in the second separation wall 71b located at a deeper position than the first separation wall 71a, is a solid-state imaging device with a planar shape.

[0122] For example, the display unit 605 is configured with a thin-film display such as a liquid crystal display (LCD) or an organic electroluminescent (EL) display, and displays moving or still images captured by the solid-state imaging device 602. The recording unit 606 records the moving or still images captured by the solid-state imaging device 602 into a recording medium such as a hard disk or a semiconductor memory.

[0123] The operation unit 607 issues operation commands for various functions of the camera device 600 under the user's operation. The power supply unit 608 appropriately supplies various power supplies for operation to the DSP circuit 603, frame memory 604, display unit 605, recording unit 606, and operation unit 607.

[0124] As described above, by using a solid-state imaging device 1 including the pixel separation section 71 as a solid-state imaging device 602, the transmission design of the photodiode PD can be improved and the saturation charge Qs can be increased. Therefore, even in imaging devices 600 such as video cameras, digital still cameras, or camera modules for mobile devices such as mobile phones, high-quality images can be acquired.

[0125] 10. Examples of applications involving moving objects The technology disclosed herein (the Technology) can be applied to a variety of products. For example, the Technology disclosed herein can be implemented as a device that can be installed on any type of mobile body such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, and robots.

[0126] Figure 24 This is a block diagram illustrating a schematic configuration example of a vehicle control system, which is an example of a mobile body control system to which the technology according to embodiments of the present disclosure can be applied.

[0127] The vehicle control system 12000 includes multiple electronic control units interconnected via a communication network 12001. Figure 24 In the example shown, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and a comprehensive control unit 12050. Furthermore, as part of the functional configuration of the comprehensive control unit 12050, a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown.

[0128] The drive system control unit 12010 controls the operation of devices related to the vehicle's drive system according to various types of programs. For example, the drive system control unit 12010 is used as a control device for devices such as an internal combustion engine or drive motor for generating vehicle driving force, a drive force transmission mechanism for transmitting driving force to the wheels, a steering mechanism for adjusting the vehicle's steering angle, and a braking device for generating vehicle braking force.

[0129] The body system control unit 12020 controls the operation of various types of devices installed on the vehicle body according to various types of programs. For example, the body system control unit 12020 is used as a control device for keyless entry systems, smart key systems, power windows, or various lights such as headlights, reversing lights, brake lights, turn signals, or fog lights. In this case, radio waves or signals of various types of switches sent from a keyless entry device can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signal inputs and controls the vehicle's door locks, power windows, lights, etc.

[0130] The exterior information detection unit 12030 detects information about the exterior of the vehicle, including information from the vehicle control system 12000. For example, the exterior information detection unit 12030 is connected to a camera unit 12031. The exterior information detection unit 12030 causes the camera unit 12031 to capture images of the exterior of the vehicle and receives the captured images. Based on the received images, the exterior information detection unit 12030 can perform detection processing for objects such as people, vehicles, obstacles, signs, or characters on the road surface, or it can perform distance detection processing to these objects.

[0131] The camera unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The camera unit 12031 can output the electrical signal as an image or as ranging information. Furthermore, the light received by the camera unit 12031 can be visible light or invisible light such as infrared light.

[0132] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected, for example, to a driver state detection unit 12041 that detects the driver's state. The driver state detection unit 12041 includes, for example, a camera that captures images of the driver. Based on the detection information input from the driver state detection unit 12041, the in-vehicle information detection unit 12040 can calculate the driver's fatigue level or concentration level, or determine whether the driver is dozing off.

[0133] The microcomputer 12051 can calculate control target values ​​for the drive force generating device, steering mechanism, or braking device based on information about the exterior or interior of the vehicle obtained by the exterior information detection unit 12030 or the interior information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing advanced driver assistance system (ADAS) functions, including collision avoidance or impact mitigation, distance-based following, speed maintenance, collision warning, or lane departure warning.

[0134] Furthermore, by controlling the drive force generating device, steering mechanism, or braking device based on information about the exterior or interior of the vehicle obtained by the exterior information detection unit 12030 or the interior information detection unit 12040, the microcomputer 12051 can perform coordinated control aimed at achieving autonomous driving, etc., which enables the vehicle to drive autonomously without relying on the driver's operation.

[0135] Furthermore, based on the information about the exterior of the vehicle obtained by the exterior information detection unit 12030, the microcomputer 12051 can output control commands to the body system control unit 12020. For example, the microcomputer 12051 can, for instance, perform coordinated control aimed at preventing glare by controlling the headlights to switch from high beam to low beam, based on the position of the vehicle ahead or oncoming vehicle detected by the exterior information detection unit 12030.

[0136] The sound / image output unit 12052 sends an output signal of at least one of sound and image to an output device capable of visually or audibly notifying vehicle occupants or the outside of the vehicle. Figure 24In the example, an audio speaker 12061, a display unit 12062, and a dashboard 12063 are shown as output devices. For example, the display unit 12062 may include at least one of an in-vehicle display and a head-up display.

[0137] Figure 25 This is a diagram showing an example of the mounting position of the camera unit 12031.

[0138] exist Figure 25 In the vehicle 12100, camera units 12101, 12102, 12103, 12104 and 12105 are used as camera unit 12031.

[0139] Cameras 12101, 12102, 12103, 12104, and 12105 are installed, for example, at the front nose, rearview mirrors, rear bumper, and rear door of vehicle 12100, as well as at the upper part of the windshield inside the passenger compartment. Camera 12101 at the front nose and camera 12105 at the upper part of the windshield inside the passenger compartment primarily acquire images of the front of vehicle 12100. Cameras 12102 and 12103 at the rearview mirrors primarily acquire images of the sides of vehicle 12100. Camera 12104 at the rear bumper or rear door primarily acquires images of the rear of vehicle 12100. The images of the front acquired by cameras 12101 and 12105 are mainly used to detect vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes ahead.

[0140] Incidentally, Figure 25 Examples of the camera ranges of camera units 12101 to 12104 are shown. Camera range 12111 represents the camera range of camera unit 12101 located at the front nose. Camera ranges 12112 and 12113 represent the camera ranges of camera units 12102 and 12103 located at the rearview mirrors, respectively. Camera range 12114 represents the camera range of camera unit 12104 located at the rear bumper or rear door. For example, by overlaying the image data captured by camera units 12101 to 12104, a bird's-eye view of vehicle 12100 from above is obtained.

[0141] At least one of the camera units 12101 to 12104 may have the function of obtaining distance information. For example, at least one of the camera units 12101 to 12104 may be a stereo camera composed of multiple camera elements, or may be a camera element having pixels for phase difference detection.

[0142] For example, based on distance information obtained from cameras 12101 to 12104, microcomputer 12051 can determine the distance to each three-dimensional object within the camera range 12111 to 12114 and the time change of said distance (relative speed to vehicle 12100), thereby extracting the nearest three-dimensional object as the vehicle ahead. Specifically, this three-dimensional object exists on the driving path of vehicle 12100 and is traveling in approximately the same direction as vehicle 12100 at a predetermined speed (e.g., equal to or greater than 0 km / h). Furthermore, microcomputer 12051 can preset the distance to be maintained between itself and the vehicle ahead, and execute automatic braking control (including follow-stop control) or automatic acceleration control (including follow-start control), etc. Therefore, cooperative control, such as autonomous driving, which aims to enable the vehicle to drive autonomously without relying on driver operation, can be performed.

[0143] For example, based on distance information obtained from cameras 12101 to 12104, microcomputer 12051 can classify three-dimensional object data into three-dimensional object data for two-wheeled vehicles, standard vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects, extract the classified three-dimensional object data, and use the extracted three-dimensional object data to automatically avoid obstacles. For example, microcomputer 12051 identifies obstacles around vehicle 12100 as obstacles that the driver of vehicle 12100 can visually recognize and obstacles that the driver of vehicle 12100 cannot visually recognize. Then, microcomputer 12051 determines the collision risk to indicate the degree of danger of colliding with each obstacle. If the collision risk is equal to or higher than a set value and there is therefore a possibility of collision, microcomputer 12051 outputs a warning to the driver via audio speaker 12061 or display unit 12062, and performs forced deceleration or evasive steering via drive system control unit 12010. Therefore, microcomputer 12051 can assist driving to avoid collisions.

[0144] At least one of the camera units 12101 to 12104 can be an infrared camera that detects infrared light. The microcomputer 12051 can identify a pedestrian, for example, by determining whether a pedestrian exists in the captured images of the camera units 12101 to 12104. This pedestrian identification is performed, for example, by the following steps: extracting feature points from the captured images of the camera units 12101 to 12104, which are infrared cameras; and determining whether it is a pedestrian by performing pattern matching processing on a series of feature points representing the outline of an object. If the microcomputer 12051 determines that a pedestrian exists in the captured images of the camera units 12101 to 12104 and thus identifies the pedestrian, the sound / image output unit 12052 controls the display unit 12062 so that a square outline for emphasis is displayed superimposed on the identified pedestrian. The sound / image output unit 12052 can also control the display unit 12062 so that an icon or similar representing a pedestrian is displayed at a desired location.

[0145] Examples of vehicle control systems to which the technology according to this disclosure can be applied have been described above. The technology according to this disclosure can be applied to the camera unit 12031 in the above configuration. Specifically, the solid-state camera device 1 can be used as the camera unit 12031. By applying the technology according to this disclosure to the camera unit 12031, easier-to-view camera images and distance information can be obtained while reducing its size. Furthermore, by using the obtained camera images and distance information, driver fatigue can be reduced, and the safety of the driver and the vehicle can be improved.

[0146] In the above examples, a solid-state imaging device has been described in which the first conductivity type is P-type, the second conductivity type is N-type, and electrons are used as signal charges. However, this disclosure can also be applied to solid-state imaging devices in which holes are used as signal charges. That is, the first conductivity type can be N-type, the second conductivity type can be P-type, and the aforementioned semiconductor region can be composed of semiconductor regions of opposite conductivity types.

[0147] Furthermore, although examples of applying the technology of this disclosure to solid-state imaging devices that output image signals have been described, the technology of this disclosure can be applied not only to solid-state imaging devices but also to general light detection devices including pixels that receive incident light and perform photoelectric conversion on the incident light. For example, the technology of this disclosure can be applied to light receiving devices (distance measurement sensors) of distance measurement systems that receive infrared light emitted as active light and measure the distance to a subject using a direct ToF method or an indirect ToF method. Furthermore, the technology of this disclosure is not limited to solid-state imaging devices that detect the distribution of incident visible light and capture an image of that distribution, but can also be applied to solid-state imaging devices that capture an image of the distribution of incident infrared, X-ray, or particle light, or more broadly, to general solid-state imaging devices (physical quantity distribution detection devices), such as fingerprint sensors that detect the distribution of other physical quantities such as pressure or electrostatic capacitance and capture an image of that distribution.

[0148] The embodiments disclosed herein are not limited to the above embodiments, and various modifications can be made without departing from the technical essence of this disclosure. For example, a combination of all or some of the above configuration examples can be used.

[0149] The effects described in this specification are merely illustrative and not limited, and may provide effects beyond those described in this specification.

[0150] Note that the technology disclosed herein can also be configured as follows. (1) A light detection device, comprising: A photoelectric conversion region, which is formed in a semiconductor substrate; and A pixel separation section extends through the semiconductor substrate and separates the photoelectric conversion region for each pixel. The pixel separation section includes a first separation wall on the first surface side of the semiconductor substrate and a second separation wall on the second surface side of the semiconductor substrate, wherein the second surface is opposite to the first surface. The first separation wall and the second separation wall have different widths, and Regarding the width of the photoelectric conversion region to the second separation wall in the direction perpendicular to the center line, the first width of the edge center of the pixel is configured to be greater than the second width of the corner near the pixel, and the center line divides the photoelectric conversion region in two in the horizontal or vertical direction. (2) The optical detection device according to (1), wherein, Assuming that the width from the center of the edge of the photoelectric conversion region to the first separation wall in a direction perpendicular to the center line is defined as the third width, and the width from the corner of the photoelectric conversion region to the first separation wall is defined as the fourth width, the first width from the center of the edge to the second separation wall is configured to be greater than the third width to the first separation wall. (3) The optical detection device according to (1) or (2), wherein, Assume that the width from the center of the edge of the photoelectric conversion region to the first separation wall in the direction perpendicular to the center line is defined as the third width, and the width from the corner of the photoelectric conversion region to the first separation wall is defined as the fourth width, and the second width from the corner to the second separation wall is configured to be smaller than the fourth width to the first separation wall. (4) The light detection device according to any one of (1) to (3), wherein, The planar shape of the pixel separation section is configured to be different when viewed from the first surface side of the semiconductor substrate and when viewed from the second surface side. (5) The light detection apparatus according to any one of (1) to (4), wherein, The width of the first separation wall is configured to be greater than the width of the second separation wall. (6) The light detection apparatus according to any one of (1) to (5), wherein, The first surface of the semiconductor substrate is the front surface of the semiconductor substrate, and The second surface of the semiconductor substrate is the back surface of the semiconductor substrate. (7) The light detection apparatus according to any one of (1) to (6), wherein, The first separating wall has a generally rectangular planar shape, and The second separation wall has a generally circular or generally octagonal planar shape. (8) The light detection apparatus according to any one of (1) to (7), wherein, On the sidewall of the second separation wall, semiconductor regions of a first conductivity type and semiconductor regions of a second conductivity type opposite to the first conductivity type are arranged sequentially toward the center of the pixel. (9) The light detection apparatus according to any one of (1) to (8), wherein, The pixel separation section is configured by embedding a conductive material and is configured to apply a predetermined bias voltage to the conductive material. (10) The light detection apparatus according to any one of (1) to (8), wherein, The pixel separation section is configured by embedding conductive material in a central portion sandwiched by an insulating film in a planar view, and is configured to apply a predetermined bias voltage to the conductive material. (11) The light detection apparatus according to any one of (1) to (8), wherein, The pixel separation section is configured by embedding an insulating film. (12) The light detection apparatus according to any one of (1) to (11) further comprises: Overflow path between the two photoelectric conversion regions. (13) The light detection apparatus according to any one of (1) to (12) further comprises: Overflow path, where The planar shape of the pixel, including the photoelectric conversion region, is configured as a rectangular shape. The two pixel regions form a square shape, and The overflow path is formed between the photoelectric conversion regions of the two pixels having the square shape. (14) The light detection apparatus according to any one of (1) to (13), wherein, The planar shape of the pixel including the photoelectric conversion region is configured as a rectangular shape, and the square unit pixel is arranged by offsetting the pixel position of the square unit pixel having a square shape formed by two pixel regions from the square unit pixel of another adjacent pixel column or another adjacent pixel row by half the pixel size. (15) The optical detection device according to (14), wherein, The pixel column is any one of the following: a pixel column with only a green filter, a pixel column with alternating green and red filters, and a pixel column with alternating green and blue filters. (16) The light detection apparatus according to any one of (1) to (12), wherein, The planar shape of the pixel including the photoelectric conversion region is configured as a rectangular shape, and the square unit pixel having a square shape formed by two pixel regions has a filter array in which the red color filter, green color filter or blue color filter is arranged in units of 2×2 square unit pixels. (17) The light detection apparatus according to any one of (1) to (12), wherein, The pixel is arranged by offsetting the pixel position of the pixel including the photoelectric conversion region from the pixel position of another adjacent pixel column or another adjacent pixel row by half the pixel size. (18) An electronic device comprising a light detection device, the light detection device comprising: A photoelectric conversion region, which is formed in a semiconductor substrate; and A pixel separation section extends through the semiconductor substrate and separates the photoelectric conversion region for each pixel. The pixel separation section includes a first separation wall on the first surface side of the semiconductor substrate and a second separation wall on the second surface side of the semiconductor substrate, wherein the second surface is opposite to the first surface. The first separation wall and the second separation wall have different widths, and Regarding the width of the photoelectric conversion region to the second separation wall in the direction perpendicular to the center line, the first width of the edge center of the pixel is configured to be greater than the second width of the corner near the pixel, and the center line divides the photoelectric conversion region in two in the horizontal or vertical direction. List of reference numerals

[0151] 1. Solid-state imaging device, 11-pixel array, 21 pixels, 51 semiconductor substrate, 51a first surface, 51b second surface, 61 P-type semiconductor region, 62 N-type semiconductor region, 71 pixel separation section, 71a, 71a' first separation wall, 71b, 71b' second separation wall, 72 sidewall, 73 insulating film, 74 P-type semiconductor region, 75 N-type semiconductor region, 81 planarization film, 82 light-shielding film, 241 conductive material, 301 overflow path, 311 on-chip lens, 341 color filter, 600 imaging device, 602 solid-state imaging device, HLb1 first width, HLb2 second width, HUa1 first width, HUa2 second width, VLb1 first width, VLb2 second width, VUa1 first width, VUa2 second width, PD photodiode, RST reset transistor, SEL select transistor, TG transfer transistor, AMP Amplifying transistor, FD floating diffusion region

Claims

1. A light detection device, comprising: The photoelectric conversion region is formed in the semiconductor substrate; as well as A pixel separation section extends through the semiconductor substrate and separates the photoelectric conversion region for each pixel. The pixel separation section includes a first separation wall on the first surface side of the semiconductor substrate and a second separation wall on the second surface side of the semiconductor substrate, wherein the second surface is opposite to the first surface. The first separation wall and the second separation wall have different widths, and Regarding the width of the photoelectric conversion region to the second separation wall in the direction perpendicular to the center line, the first width of the edge center of the pixel is configured to be greater than the second width of the corner near the pixel, and the center line divides the photoelectric conversion region in two in the horizontal or vertical direction.

2. The optical detection device according to claim 1, wherein, Assuming that the width from the center of the edge of the photoelectric conversion region to the first separation wall in a direction perpendicular to the center line is defined as the third width, and the width from the corner of the photoelectric conversion region to the first separation wall is defined as the fourth width, the first width from the center of the edge to the second separation wall is configured to be greater than the third width to the first separation wall.

3. The optical detection device according to claim 1, wherein, Assume that the width from the center of the edge of the photoelectric conversion region to the first separation wall in the direction perpendicular to the center line is defined as the third width, and the width from the corner of the photoelectric conversion region to the first separation wall is defined as the fourth width, and the second width from the corner to the second separation wall is configured to be smaller than the fourth width to the first separation wall.

4. The optical detection device according to claim 1, wherein, The planar shape of the pixel separation section is configured to be different when viewed from the first surface side of the semiconductor substrate and when viewed from the second surface side.

5. The optical detection device according to claim 1, wherein, The width of the first separation wall is configured to be greater than the width of the second separation wall.

6. The optical detection device according to claim 1, wherein, The first surface of the semiconductor substrate is the front surface of the semiconductor substrate, and The second surface of the semiconductor substrate is the back surface of the semiconductor substrate.

7. The optical detection device according to claim 1, wherein, The first separating wall has a generally rectangular planar shape, and The second separation wall has a generally circular or generally octagonal planar shape.

8. The optical detection device according to claim 1, wherein, On the sidewall of the second separation wall, semiconductor regions of a first conductivity type and semiconductor regions of a second conductivity type opposite to the first conductivity type are arranged sequentially toward the center of the pixel.

9. The optical detection device according to claim 1, wherein, The pixel separation section is configured by embedding a conductive material and is configured to apply a predetermined bias voltage to the conductive material.

10. The optical detection device according to claim 1, wherein, The pixel separation section is configured by embedding conductive material in a central portion sandwiched by an insulating film in a planar view, and is configured to apply a predetermined bias voltage to the conductive material.

11. The optical detection device according to claim 1, wherein, The pixel separation section is configured by embedding an insulating film.

12. The optical detection device according to claim 1, further comprising: Overflow path between the two photoelectric conversion regions.

13. The optical detection device according to claim 1, further comprising: Overflow path, where The planar shape of the pixel, including the photoelectric conversion region, is configured as a rectangular shape. The two pixel regions form a square shape, and The overflow path is formed between the photoelectric conversion regions of the two pixels having the square shape.

14. The optical detection device according to claim 1, wherein, The planar shape of the pixel including the photoelectric conversion region is configured as a rectangular shape, and the square unit pixel is arranged by offsetting the pixel position of the square unit pixel having a square shape formed by two pixel regions from the square unit pixel of another adjacent pixel column or another adjacent pixel row by half the pixel size.

15. The optical detection device according to claim 14, wherein, The pixel column is any one of the following: a pixel column with only a green filter, a pixel column with alternating green and red filters, and a pixel column with alternating green and blue filters.

16. The optical detection device according to claim 1, wherein, The planar shape of the pixel including the photoelectric conversion region is configured as a rectangular shape, and the square unit pixel having a square shape formed by two pixel regions has a filter array in which the red color filter, green color filter or blue color filter is arranged in units of 2×2 square unit pixels.

17. The optical detection device according to claim 1, wherein, The pixel is arranged by offsetting the pixel position of the pixel including the photoelectric conversion region from the pixel position of another adjacent pixel column or another adjacent pixel row by half the pixel size.

18. An electronic device comprising a light detection device, the light detection device comprising: The photoelectric conversion region is formed in the semiconductor substrate; as well as A pixel separation section extends through the semiconductor substrate and separates the photoelectric conversion region for each pixel. The pixel separation section includes a first separation wall on the first surface side of the semiconductor substrate and a second separation wall on the second surface side of the semiconductor substrate, wherein the second surface is opposite to the first surface. The first separation wall and the second separation wall have different widths, and Regarding the width of the photoelectric conversion region to the second separation wall in the direction perpendicular to the center line, the first width of the edge center of the pixel is configured to be greater than the second width of the corner near the pixel, and the center line divides the photoelectric conversion region in two in the horizontal or vertical direction.

Images