Solid-state imaging device and electronic device

Abstract

Provided is a solid-state imaging element with which it is possible to obtain higher quality captured images. Also provided is an electronic device. A solid-state imaging element according to the present disclosure is provided with a pixel array (11) in which pixels are arranged in a matrix arrangement, said pixels each including: a photoelectric conversion section (21) that converts light into electric charge by means of photoelectric conversion; and an electric charge accumulation section (24) that abuts the photoelectric conversion section and accumulates electric charge transferred from the photoelectric conversion section. The pixels are arranged such that the direction of the abutment between the photoelectric conversion section and the electric charge accumulation section relative to the pixel array faces a direction that corresponds to the position within the pixel array.

Description

[Technical field]

[0001] The present disclosure relates to a solid-state imaging device and an electronic device. [Background technology]

[0002] Solid-state imaging devices, such as back-illuminated CMOS (Complementary Metal Oxide Semiconductor) image sensors having a global shutter function, are known. In such CMOS image sensors, a charge storage section that temporarily stores charges generated in a photoelectric conversion section is provided in a semiconductor substrate. When light is incident on this charge storage section, unnecessary charges are generated. The unnecessary charges cause optical noise, which degrades image quality.

[0003] In order to suppress the incidence of light into the charge storage section, a structure has been proposed in which a light shielding section for separating the photoelectric conversion section and the charge storage section is formed by digging a non-penetrating light shielding section non-penetratingly from the back surface side (the irradiation surface side) in the structure in the layer direction of the pixel (for example, Patent Document 1). The charge accumulated in the photoelectric conversion section is transferred to the charge storage section via the non-penetrating part of the light shielding section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO 19 / 069556 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the configuration of Patent Document 1, there is a risk that light may leak into the charge storage section from the charge transfer section from the photoelectric conversion section to the charge storage section, that is, from the non-penetrating section of the light-shielding section, due to diffraction, reflection, etc. This leakage of light into the charge storage section causes noise and leads to a degradation of the global shutter function, such as deterioration of the image quality of the captured image.

[0006] An object of the present disclosure is to provide a solid-state imaging device and an electronic device capable of acquiring higher quality images. [Means for solving the problem]

[0007] The solid-state imaging element according to the present disclosure includes a pixel array in which pixels, each including a photoelectric conversion unit that converts light into an electric charge by photoelectric conversion and a charge accumulation unit adjacent to the photoelectric conversion unit and that accumulates the electric charge transferred from the photoelectric conversion unit, are arranged in a matrix, and the pixel is arranged such that a direction in which the photoelectric conversion unit is adjacent to the charge accumulation unit is determined as a direction according to a position within the pixel array. and a direction in which the photoelectric conversion unit is located outside the pixel array with respect to the charge accumulation unit; is positioned towards. [Brief description of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an example of the configuration of a CMOS image sensor which is an example of a solid-state imaging element applicable to each embodiment. [Diagram 2] 1 is a diagram illustrating an outline of a configuration example of a unit pixel applicable to each embodiment. [Diagram 3] FIG. 2 is a cross-sectional view illustrating a basic structure of a light blocking structure that can be applied to each embodiment. [Figure 4A] FIG. 2 is a diagram for roughly explaining the optical configuration of a CMOS image sensor applicable to each embodiment. [Figure 4B] FIG. 2 is a diagram for roughly explaining the optical configuration of a CMOS image sensor applicable to each embodiment. [Figure 5A] FIG. 1 is a cross-sectional view illustrating a schematic structure of an example of a pixel according to an existing technique. [Figure 5B] 4A to 4C are schematic diagrams illustrating examples of arrangements of non-penetrating light-shielding portions and penetrating light-shielding portions in a pixel, as viewed from the incident surface side. [Figure 6] FIG. 1 is a diagram illustrating an example of an arrangement of pixels in a pixel array unit according to existing technology. [Figure 7] FIG. 2 is a diagram illustrating an example of an arrangement of pixels in a pixel array portion according to the first embodiment. [Figure 8A] FIG. 4 is a schematic diagram showing a more specific example of a pixel arrangement according to the first embodiment. [Figure 8B] FIG. 4 is a schematic diagram showing a more specific example of a pixel arrangement according to the first embodiment. [Figure 9A] FIG. 4 is a schematic diagram for explaining an optical waveguide according to a first modified example of the first embodiment. [Figure 9B] FIG. 4 is a schematic diagram for explaining an optical waveguide according to a first modified example of the first embodiment. [Figure 9C] FIG. 4 is a schematic diagram for explaining an optical waveguide according to a first modified example of the first embodiment. [Figure 10] FIG. 11 is a schematic diagram showing an example of wiring to each pixel according to a second modified example of the first embodiment. [Figure 11A] 13 is a schematic diagram showing a second example of an arrangement of non-penetrating light-shielding parts and penetrating light-shielding parts in a pixel according to the third modified example of the first embodiment, as viewed from the incident surface side. FIG. [Figure 11B] 13 is a schematic diagram of a third example of an arrangement of non-penetrating light-shielding parts and penetrating light-shielding parts in a pixel according to a third modified example of the first embodiment, as viewed from the incident surface side. FIG. [Figure 12] FIG. 11 is a schematic diagram showing a more specific example of the arrangement of the pixels 20 according to the second embodiment. [Figure 13A] FIG. 11 is a schematic diagram for explaining an optical waveguide according to a modified example of the second embodiment. [Figure 13B] FIG. 11 is a schematic diagram for explaining an optical waveguide according to a modified example of the second embodiment. [Figure 13C] FIG. 11 is a schematic diagram for explaining an optical waveguide according to a modified example of the second embodiment. [Figure 14] FIG. 11 is a block diagram illustrating a schematic configuration of an example of an imaging device as an electronic device according to a third embodiment. [Figure 15] 1A to 1C are diagrams showing examples of use of a CMOS image sensor 10 according to a first embodiment, a second embodiment, and each of the modifications thereof. [Figure 16]1 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied. [Figure 17] 2 is a block diagram showing an example of a functional configuration of a camera head and a CCU. FIG. [Figure 18] 1 is a block diagram showing a schematic configuration example of a vehicle control system that is an example of a mobile object control system to which the technology according to the present disclosure can be applied. [Figure 19] FIG. 4 is a diagram showing an example of an installation position of an imaging unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following embodiments, the same components are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0010] Hereinafter, embodiments of the present disclosure will be described in the following order. 1. Configurations Applicable to Each Embodiment 1-1. Solid-state imaging device applicable to each embodiment 1-2. Configuration examples of unit pixels applicable to each embodiment 1-3. Light-shielding structure in unit pixel applicable to each embodiment 1-4. Optical configuration of CMOS image sensor applicable to each embodiment 2. Description of existing technology 3. First embodiment 3-1. First modified example of the first embodiment 3-2. Second Modification of the First Embodiment 3-3. Third Modification of the First Embodiment 4. Second embodiment 4-1. Modification of the second embodiment 5. Third embodiment 6. Fourth embodiment 6-1. Application examples for endoscopic surgery systems 6-2. Application examples for moving objects

[0011] [1. Configuration applicable to each embodiment] First, an example of an apparatus configuration applicable to each embodiment of the present disclosure will be described. A solid-state imaging device according to the present disclosure is suitable for use in an imaging device having a global shutter function.

[0012] (1-1. Solid-state imaging device applicable to each embodiment) FIG. 1 is a block diagram showing an example of the configuration of a CMOS (Complementary Metal Oxide Semiconductor) image sensor, which is an example of a solid-state imaging device applicable to each embodiment.

[0013] 1, a CMOS image sensor 10 includes a pixel array section 11, a vertical drive section 12, a column processing section 13, a horizontal drive section 14, and a system control section 15. The pixel array section 11, the vertical drive section 12, the column processing section 13, the horizontal drive section 14, and the system control section 15 are formed on a semiconductor substrate (chip) not shown.

[0014] In the pixel array section 11, unit pixels 20 each having a photoelectric conversion section that generates and internally accumulates photocharges whose amount corresponds to the amount of incident light are two-dimensionally arranged in a matrix array. The unit pixels 20 have a back-illuminated pixel structure (see FIG. 3). Hereinafter, the photocharge whose amount corresponds to the amount of incident light may be simply referred to as "charge", and the unit pixel may be simply referred to as "pixel".

[0015] The pixel array unit 11 further includes pixel drive lines 16 (161 to 166) for each row of a pixel array of m rows by n columns (m and n are each an integer of 1 or more). m ) are formed in the left-right direction of the figure (the direction in which the pixels in the pixel row are arranged), and vertical signal lines 17 (171 to 17 n ) are formed in the vertical direction of the figure (the direction in which the pixels in the pixel column are arranged). The vertical signal lines 17 are also called VSL. One end of the pixel drive line 16 is connected to an output terminal of the vertical drive unit 12 corresponding to each row.

[0016] The CMOS image sensor 10 further includes a signal processing unit 18 and a data storage unit 19. The signal processing unit 18 and the data storage unit 19 may be an external signal processing unit provided on a substrate separate from the CMOS image sensor 10, such as a DSP (Digital Signal Processor) or software processing, or may be mounted on the same substrate as the CMOS image sensor 10.

[0017] The vertical drive unit 12 is a pixel drive unit that is composed of a shift register, an address decoder, etc., and drives each pixel 20 of the pixel array unit 11 all at once or in units of rows, etc. Although the specific configuration of this vertical drive unit 12 is not shown in the figure, it is configured to have a read scanning system and a sweep-out scanning system, and can perform batch sweep-out and batch transfer under the driving of these scanning systems.

[0018] The readout scanning system sequentially selects and scans the unit pixels 20 of the pixel array section 11 row by row to read out signals from the unit pixels 20. In the case of row driving (rolling shutter operation), sweep-out scanning is performed for the readout row on which read-out scanning is performed by the readout scanning system, the sweep-out scanning is performed a time period equal to the shutter speed prior to the readout scanning. In the case of global exposure (global shutter operation), sweep-out is performed a time period equal to the shutter speed prior to the batch transfer.

[0019] This sweeping out sweeps out (resets) unnecessary charges from the photoelectric conversion units of the unit pixels 20 in the readout row. Then, the sweeping out (resetting) of unnecessary charges performs a so-called electronic shutter operation. Here, the electronic shutter operation refers to an operation of discarding the photoelectric charges in the photoelectric conversion units and starting a new exposure (starting the accumulation of photoelectric charges).

[0020] The signal read by the readout operation by the readout scanning system corresponds to the amount of light that has entered since the previous readout operation or electronic shutter operation. In the case of row driving, the period from the readout timing of the previous readout operation or the sweep timing of the electronic shutter operation to the readout timing of the current readout operation is the accumulation period (exposure period) of the photocharge in the unit pixel. In the case of global exposure, the period from the batch sweep to the batch transfer is the accumulation period (exposure period).

[0021] The pixel signals output from each unit pixel 20 in a pixel row selected and scanned by the vertical drive section 12 are supplied to the column processing section 13 through each vertical signal line 17. The column processing section 13 performs predetermined signal processing on the pixel signals output from each unit pixel 20 in the selected row through the vertical signal line 17 for each pixel column in the pixel array section 11, and temporarily holds the pixel signals after signal processing.

[0022] Specifically, the column processing unit 13 performs at least a noise removal process, such as a CDS (Correlated Double Sampling) process, as signal processing. The correlated double sampling by the column processing unit 13 removes pixel-specific fixed pattern noise such as reset noise and threshold variation of an amplifier transistor (see FIG. 2). Note that, in addition to the noise removal process, the column processing unit 13 may also be provided with an AD (analog-digital) conversion function, for example, to output the signal level as a digital signal.

[0023] The horizontal driving unit 14 is composed of a shift register, an address decoder, etc., and sequentially selects unit circuits corresponding to pixel columns in the column processing unit 13. By selective scanning by this horizontal driving unit 14, pixel signals that have been signal-processed in the column processing unit 13 are sequentially output to the signal processing unit 18.

[0024] The system control unit 15 is composed of a timing generator that generates various timing signals, and controls the driving of the vertical driving unit 12, the column processing unit 13, the horizontal driving unit 14, etc. based on the various timing signals generated by the timing generator.

[0025] The signal processing unit 18 has at least an addition processing function, and performs various signal processing such as addition processing on the pixel signals output from the column processing unit 13. The data storage unit 19 temporarily stores data necessary for the signal processing in the signal processing unit 18.

[0026] (1-2. Configuration Examples of Unit Pixels Applicable to Each Embodiment) Next, a specific configuration of the unit pixel 20 applicable to each embodiment will be described. Fig. 2 is a diagram showing an outline of a configuration example of the unit pixel 20 applicable to each embodiment. The unit pixel 20 has, for example, a photodiode (PD) 21 as a photoelectric conversion section. The photodiode 21 is, for example, a buried type photodiode formed by forming a p-type layer 211 on the substrate surface side of a p-type well layer 32 formed on an n-type semiconductor substrate 31 and burying an n-type buried layer 212. Note that the n-type buried layer 212 has an impurity concentration that causes a depletion state when electric charges are discharged.

[0027] In addition to a photodiode 21, the unit pixel 20 includes a first transfer gate section 22, a second transfer gate section 23, and a charge holding section (MEM) 24. The first transfer gate section 22 has a gate electrode 221 arranged at a position spanning the photodiode 21 and the charge holding section 24. The second transfer gate section 23 has a gate electrode 231 arranged in the vicinity of the charge holding section 24.

[0028] In the unit pixel 20 of this example, the charge retention portion 24 is configured to be formed of a buried n-type diffusion region 242 with a p-type layer 241 as the surface. In this way, even when the charge retention portion 24 is formed of the n-type diffusion region 242, it is possible to obtain the same effects and advantages as when the charge retention portion 24 is formed of a buried channel. Specifically, by forming the n-type diffusion region 242 inside the p-type well layer 32 and forming the p-type layer 241 on the substrate surface side, it is possible to prevent the dark current generated at the Si-SiO2 interface from accumulating in the n-type diffusion region 242 of the charge retention portion 24, which contributes to improving image quality.

[0029] When a drive signal TRY is applied to the gate electrode 221, the first transfer gate unit 22 transfers the charge that has been photoelectrically converted by the photodiode 21 and accumulated inside the photodiode 21 to the charge holding unit 24. The first transfer gate unit 22 also functions as a gate for preventing the backflow of charge from the charge holding unit 24 to the photodiode 21.

[0030] In the second transfer gate unit 23, the gate electrode 221 functions as a gate when transferring charges from the photodiode 21 to the charge holding unit 24, and also functions as a gate for holding charges in the charge holding unit 24. The gate electrode 221 functions as a gate when transferring charges from the charge holding unit 24 to a floating diffusion region (FD: Floating Diffusion) 25, and also functions as a gate for holding charges in the charge holding unit 24. The floating diffusion region 25 is a charge-voltage conversion unit made of an n-type layer.

[0031] In the second transfer gate unit 23, a driving signal TX is applied to the gate electrode 231, thereby modulating the charge holding unit 24. That is, the potential of the charge holding unit 24 deepens by applying the driving signal TX to the gate electrode 231. This makes it possible to increase the amount of saturated charge in the charge holding unit 24 compared to the case where modulation is not applied.

[0032] The unit pixel 20 further has a third transfer gate section 26. When a drive signal TRG is applied to a gate electrode 261, the third transfer gate section 26 transfers the charges stored in the charge holding section 24 to the floating diffusion region 25. The floating diffusion region 25 converts the charges transferred from the charge holding section 24 by the third transfer gate section 26 into a voltage.

[0033] The unit pixel 20 further includes a reset transistor 27, an amplifying transistor 28, and a selecting transistor 29. Note that, although an example in which n-channel MOS transistors are used for the reset transistor 27, the amplifying transistor 28, and the selecting transistor 29 is shown in Fig. 2, the combination of the conductivity types of the reset transistor 27, the amplifying transistor 28, and the selecting transistor 29 is not limited to this combination.

[0034] The reset transistor 27 is connected to the power supply voltage V rst The amplifier transistor 28 is connected between the node and the floating diffusion region 25, and resets the floating diffusion region 25 by applying a drive signal RST to the gate electrode. dd The gate electrode is connected to the floating diffusion region 25 and reads out the voltage of the floating diffusion region 25.

[0035] The selection transistor 29 has, for example, a drain electrode connected to the source electrode of the amplification transistor 28 and a source electrode connected to the vertical signal line 17 (VSL), and selects the unit pixel 20 from which a pixel signal is to be read out by applying a drive signal SEL to the gate electrode. dd It is also possible to adopt a configuration in which the node is connected between the drain electrode of the amplifier transistor 28.

[0036] In the configuration example of the unit pixel 20 described above, one or more of the reset transistor 27, the amplifying transistor 28, and the selection transistor 29 may be omitted depending on the method of reading out the pixel signal.

[0037] 2, an n-type buried channel is formed in the p-type well layer 32, but the opposite conductivity type may be used. In this case, all of the potential relationships are reversed.

[0038] 2 is also provided with an overflow gate section 33 for preventing blooming. When a drive signal OFG is applied to a gate electrode 331 of the overflow gate section 33 at the start of exposure, the overflow gate section 33 discharges the charge of the photodiode 21 to an n-type layer 34. A predetermined voltage V dd is applied.

[0039] The CMOS image sensor 10 according to this embodiment having the unit pixels 20 described above realizes a global shutter operation (global exposure) by starting and ending exposure for all pixels simultaneously and transferring the charge accumulated in the photodiode 21 to the light-shielded charge holding unit 24. This global shutter operation makes it possible to realize distortion-free imaging due to the same exposure period for all pixels.

[0040] (1-3. Light-shielding structure in unit pixel applicable to each embodiment) Next, a light blocking structure in the unit pixel 20 that can be applied to each embodiment will be described.

[0041] Fig. 3 is a cross-sectional view showing a basic structure of a light-shielding structure applicable to each embodiment. As shown in Fig. 3, the CMOS image sensor 10 has a structure in which a semiconductor substrate 51, an insulating film layer 52, a first light-shielding film 53, and a wiring layer 54 are laminated from the upper side of the figure. The CMOS image sensor 10 is a back-illuminated solid-state imaging element that takes in light irradiated from the back side of the semiconductor substrate 51, which is the opposite side to the front side on which the wiring layer 54 is laminated, into the photodiode 21.

[0042] That is, the CMOS image sensor 10 is configured such that an insulating film layer 52, a first light-shielding film 53, and a wiring layer 54 are laminated on a second surface (front surface) of the semiconductor substrate 51 opposite to a first surface (back surface) on which light is incident, from the side closer to the second surface. The CMOS image sensor 10 is also configured such that a second light-shielding film 57 is formed between the incident surface of the semiconductor substrate 51 and the photodiode 21 and the charge storage unit 24 via a multilayer film 56. The multilayer film 56 is, for example, made of a three-layer film including a fixed charge film, an anti-reflection film, and an insulating film. The insulating film is, for example, made of an oxide film such as a SiO2 film.

[0043] Although not shown, for example, a passivation film, a color filter, a microlens, etc. are laminated on the back surface side of the semiconductor substrate 51. In addition, for example, a support substrate is laminated under the wiring layer .

[0044] Hereinafter, the back surface of the semiconductor substrate 51 may be referred to as the incident surface. A surface of the semiconductor substrate 51 that is disposed at the boundary with the wiring layer 54 is referred to as the boundary surface. A surface of the photodiode 21 on the incident surface side of the semiconductor substrate 51 is referred to as the light receiving surface, and a surface opposite the light receiving surface is referred to as the bottom surface. A surface of the charge holding unit 24 on the incident surface side of the semiconductor substrate 51 is referred to as the top surface, and a surface opposite the top surface is referred to as the bottom surface.

[0045] The semiconductor substrate 51 is made of, for example, a silicon substrate. A photodiode 21 and a charge holding portion 24 are formed in the semiconductor substrate 51. Note that the photodiode 21 and charge holding portion 24 on the left side of the drawing are arranged in the same pixel 20, and the photodiode 21 and charge holding portion 24 on the right side are arranged in an adjacent different pixel 20.

[0046] The insulating film layer 52 is made of, for example, three insulating films, a first insulating film 52A, a second insulating film 52B, and a third insulating film 52C (three-layer structure). The first insulating film 52A and the third insulating film 52C are made of, for example, an oxide film such as a SiO2 film, and the second insulating film 52B is made of, for example, a nitride film such as a SiN film. The first insulating film 52A also serves as an insulating film between the gate electrode 55 and the semiconductor substrate 51. The gate electrode 55 corresponds to, for example, the gate electrode 221 of the first transfer gate unit 22 in FIG. 2.

[0047] The first light-shielding film 53 is made of a metal having light-shielding properties, such as tungsten. The first light-shielding film 53 is provided on the wiring layer 54 side so as to cover at least the formation region of the charge retention portion 24, preferably so as to cover the formation region of the photodiode 21 and the charge retention portion 24. The first light-shielding film 53 is provided for the purpose of preventing light that has been transmitted through the semiconductor substrate 51 without being absorbed by the photodiode 21 from entering the wiring layer 54. The action of this first light-shielding film 53 prevents the light that has been transmitted through the semiconductor substrate 51 from entering the wiring layer 54, being reflected by the wiring layer 54, and entering the charge retention portion 24.

[0048] Here, light transmitted through the semiconductor substrate 51 may be reflected by a surface of the flat portion 53C, which is the main body of the first light-shielding film 53, parallel to the semiconductor substrate 51, and may enter the charge retention portion 24. Therefore, the first light-shielding film 53 has a protrusion protruding from the flat portion 53C toward the semiconductor substrate 51 at a portion corresponding to the formation position of the second light-shielding film 57. More specifically, the first light-shielding film 53 has a protrusion 53A and a protrusion 53B at a portion corresponding to the formation position of at least one, preferably both, of a non-penetrating light-shielding portion 57B and a penetrating light-shielding portion 57C of the second light-shielding film 57, which will be described later. The protrusion 53A and the protrusion 53B are formed integrally with the flat portion 53C of the first light-shielding film 53 by a metal having light-shielding properties, such as tungsten.

[0049] The protrusions 53A and 53B are formed along the longitudinal direction of the charge retention portion 24 at a position closer to the photodiode 21 than directly below the positions where the non-penetrating light shielding portion 57B and the penetrating light shielding portion 57C of the second light shielding film 57 are formed. That is, the protrusion 53A is provided in a state where it protrudes from the flat portion 53C toward the semiconductor substrate 51 at a position closer to the photodiode 21 in the same pixel than directly below the position where the non-penetrating light shielding portion 57B is formed. The protrusion 53B is provided in a state where it protrudes from the flat portion 53C toward the semiconductor substrate 51 at a position closer to the photodiode 21 in an adjacent pixel than directly below the position where the penetrating light shielding portion 57C is formed.

[0050] The protrusions 53A and 53B act to prevent light reflected by the upper surface of the flat portion 53C of the first light-shielding film 53 from entering the charge retention portion 24. In order to prevent the light reflected by the flat portion 53C of the first light-shielding film 53 from entering the charge retention portion 24, it is preferable that the protrusion amount, i.e., the height, of the protrusions 53A and 53B is as large as possible. On the other hand, if the height of the protrusions 53A and 53B is too high, it is considered that this may cause deterioration of characteristics such as white spots due to the influence of plasma damage, etc., during processing of the protrusions 53A and 53B.

[0051] From this viewpoint, the height positions of the protrusions 53A and 53B are preferably set within the second insulating film 52B made of a nitride film such as a SiN film, which is an intermediate layer in the insulating film layer 52 having a three-layer structure, as shown in Fig. 3. However, while it is preferable that the height positions of the protrusions 53A and 53B be set within the second insulating film 52B, which is an intermediate layer, the present invention is not limited to this, and the protrusions 53A and 53B may be set within the first insulating film 52A, which is the first layer, or within the third insulating film 52C, which is the third layer.

[0052] The second light-shielding film 57 is made of a metal having light-shielding properties, such as tungsten. The second light-shielding film 57 mainly prevents light incident from the incident surface of the semiconductor substrate 51 from directly or indirectly entering the charge retention portion 24. The second light-shielding film 57 is composed of a front light-shielding portion 57A, a non-penetrating light-shielding portion 57B, and a penetrating light-shielding portion 57C.

[0053] The front surface light shielding portion 57A is a third light shielding portion, and covers the area of ​​the incident surface of the semiconductor substrate 51 excluding an area above the light receiving surface of the photodiode 21. In other words, the front surface light shielding portion 57A covers the area of ​​the light receiving surface of the semiconductor substrate 51 excluding the area where light is incident on the photodiode 21.

[0054] The non-penetrating light-shielding portion 57B is a first light-shielding portion, and extends from the incident surface of the semiconductor substrate 51 to partway through the semiconductor substrate 51. In this example, the non-penetrating light-shielding portion 57B is disposed at least between the photodiode 21 and the charge retention portion 24 in the same pixel 20.

[0055] The through-hole light shielding portion 57C is a second light shielding portion, which penetrates the semiconductor substrate 51 and extends partway through the insulating film layer 52, and in this example, penetrates the first insulating film 52A and extends to the second insulating film 52B. That is, the through-hole light shielding portion 57C extends longer than the non-through-hole light shielding portion 57B. Also, in this example, the through-hole light shielding portion 57C is disposed between the photodiode 21 and the charge holding portion 24 disposed in different pixels 20. That is, the through-hole light shielding portion 57C is disposed at least between one photodiode 21 and the other charge holding portion 24 of adjacent pixels 20.

[0056] The non-penetrating light shielding portion 57B, which is a first light shielding portion, and the penetrating light shielding portion 57C, which is a second light shielding portion, are connected via the front surface light shielding portion 57A, which is a third light shielding portion, in a direction parallel to the incident surface (first surface) of the semiconductor substrate 51. In addition, the side surface of the photodiode 21 is surrounded by the non-penetrating light shielding portion 57B and the penetrating light shielding portion 57C. In the cross section shown in FIG. 3, the photodiode 21 and the charge retention portion 24 in the same pixel 20 are adjacent to each other with the non-penetrating light shielding portion 57B interposed therebetween.

[0057] Both the non-penetrating light shielding portion 57B and the penetrating light shielding portion 57C are trench light shielding portions formed by digging down from the incident surface (first surface) of the semiconductor substrate 51 toward the boundary surface.

[0058] Here, examples of the thicknesses of the first insulating film 52A, the second insulating film 52B, and the third insulating film 52C of the insulating film layer 52 will be described.

[0059] The first insulating film 52A is set to a thickness of, for example, 10 [nm] or more. This is a thickness necessary for processing adjustment of the depth of a groove penetrating the semiconductor substrate 51 to form the penetrating light shielding portion 57C. However, since the first insulating film 52A also serves as an insulating film between the gate electrode 55 and the semiconductor substrate 51, it is not desirable to make the film too thick. Therefore, the thickness of the first insulating film 52A is preferably set to a range of, for example, 10 [nm] to 20 [nm].

[0060] The second insulating film 52B is set to a thickness of, for example, 50 [nm] or more. This is a thickness necessary for, for example, adjusting the processing of the contacts formed in the wiring layer 54 and controlling the processing of the grooves penetrating the semiconductor substrate 51 to form the through-hole light shielding portion 57C. For example, this is a thickness necessary to prevent the grooves for forming the contacts from reaching the semiconductor substrate 51, to prevent the semiconductor substrate 51 from being damaged by the processing of the contacts, and to stop the grooves penetrating the semiconductor substrate 51 to form the through-hole light shielding portion 57C with the second insulating film 52B. However, from the viewpoint of thinning the CMOS image sensor 10, it is not desirable for the second insulating film 52B to be too thick. Therefore, the thickness of the second insulating film 52B is preferably set within a range of, for example, 50 [nm] to 100 [nm].

[0061] The third insulating film 52C is set to a thickness of, for example, 25 [nm] or more. This is a thickness necessary to prevent the third insulating film 52C from being damaged and the second insulating film 52B from being exposed when, for example, the first light-shielding film 53 is processed. However, from the viewpoint of thinning the CMOS image sensor 10, it is not desirable for the third insulating film 52C to be too thick. Therefore, it is preferable that the thickness of the third insulating film 52C is set to, for example, within a range of 30 [nm] to 100 [nm].

[0062] (1-4. Optical Configuration of CMOS Image Sensor Applicable to Each Embodiment) Next, the optical configuration of the CMOS image sensor 10 applicable to each embodiment will be described in brief with reference to Figures 4A and 4B. Figure 4A is a top view of an example of the pixel array section 11 of the CMOS image sensor 10 as viewed from the incident surface side. Figure 4B is a side view of an example of the pixel array section 11 as viewed from a surface perpendicular to the incident surface.

[0063] As shown in Fig. 4A, a lens 60 is disposed with respect to a pixel array section 11 in which the pixels 20 are arranged in a matrix. The lens 60 irradiates incident light onto each pixel 20 of the pixel array section 11, and is hereinafter referred to as a main lens 60. In the examples of Figs. 4A and 4B, the position of an optical axis 61 of the main lens 60 coincides with the center position of the pixel array section 11. Also, as shown in Fig. 4B, each pixel 20 is provided with a color filter 101 and an OCL (On Chip Lens) 100 stacked on the incident surface.

[0064] 4A and 4B, light is incident from the main lens 60 in a direction approximately perpendicular to the incident surface on the pixels 20 arranged at and near the optical axis 61 of the main lens 60 in the pixel array unit 11. On the other hand, light is incident from a more oblique direction to the incident surface on the pixels 20 arranged at positions away from the optical axis 61 of the main lens 60 as the pixels move away from the optical axis 61. In order to suppress a change in the entrance pupil diameter caused by a change in the angle of incidence of light to the pixels 20 depending on the position on the pixel array unit 11, pupil correction may be performed. Pupil correction is performed, for example, by adjusting the position and shape of the OCL 100 depending on the position of the pixel 20 on the pixel array unit 11.

[0065] Light incident on the CMOS image sensor 10 is irradiated to each pixel 20 through the main lens 60. In each pixel 20, the light irradiated from the main lens 60 is incident on the semiconductor substrate 51 from the incident surface thereof through the OCL 100 and the color filter 101 into the semiconductor substrate 51. This light is received by the photodiode 21, which performs photoelectric conversion according to the received light to generate charges. The charges generated by the photodiode 21 are transferred to the charge holding section 24 through a portion where the non-penetrating light shielding section 57B is not provided, from directly below the non-penetrating light shielding section 57B to the first insulating film 52A, by applying a drive signal TRY to the gate electrode 221. The charge holding section 24 accumulates the transferred charges until the drive signal TRG is applied to the gate electrode 261. In this manner, the charge holding section 24 functions as a charge accumulation section that accumulates charges.

[0066] Hereinafter, the portion from directly below non-penetrating light-shielding portion 57B to first insulating film 52A where non-penetrating light-shielding portion 57B is not provided will be referred to as a transfer portion, as appropriate.

[0067] [2. Description of existing technology] Next, prior to the description of the present disclosure, an outline of the existing technology will be described for ease of understanding. In the arrangement of pixels 20 in pixel array section 11 according to the existing technology, a phenomenon in which light incident on photodiode 21 leaks into charge holding section 24 may occur. The leakage of light from photodiode 21 to charge holding section 24 in the pixel structure according to the existing technology will be described with reference to Figures 5A and 5B.

[0068] Fig. 5A is a cross-sectional view showing a schematic structure of an example of pixel 20 according to the existing technology, and corresponds to the structure shown in Fig. 3 described above. In Fig. 5A, semiconductor layer 110 corresponds to semiconductor substrate 51 in Fig. 3, and wiring layer 111 corresponds to wiring layer 54 and insulating film layer 52 in Fig. 3. In the example of Fig. 5A, pixel 20 is provided with an optical waveguide structure 102 for guiding light incident from OCL 100 through color filter 101 to photodiode (PD) 21 with respect to the incident surface of semiconductor substrate 51.

[0069] Fig. 5B is a schematic diagram of an example of the arrangement of trench light shielding portions, i.e., non-penetrating light shielding portion 57B and penetrating light shielding portion 57C, in pixel 20 shown in Fig. 5A, as viewed from the incident surface side. In the example of Fig. 5B, in pixel 20, penetrating light shielding portion 57C is provided around pixel 20 and is provided on a side of photodiode (PD) 21 adjacent to charge storage portion (MEM) 24.

[0070] 5B, a non-penetrating light shielding portion 57B is provided on the charge holding portion 24 side of the outer periphery of the photodiode 21 that is not adjacent to the charge holding portion 24 and that does not constitute the outer periphery of the pixel 20, and a penetrating light shielding portion 57C is provided in a portion other than the non-penetrating light shielding portion 57B. Furthermore, on a side of the charge holding portion 24 that is partially adjacent to the photodiode 21, the non-penetrating light shielding portion 57B is provided in a portion not adjacent to the photodiode 21. Charges generated by photoelectric conversion in the photodiode 21 are transferred to the charge holding portion 24 via the transfer portions of the non-penetrating light shielding portion 57B.

[0071] In the following, unless otherwise specified, "an edge of the outer periphery of the photodiode 21 that is not adjacent to the charge retention portion 24 and that does not constitute the outer periphery of the pixel 20" will be described as "an edge that is not adjacent to the charge retention portion 24 of the photodiode 21."

[0072] 5A, the leakage of light incident on the photodiode 21 into the charge holding section 24 will be described in more detail. For example, as shown by arrow A, the light incident on the photodiode 21 may be reflected by the insulating film layer 52 or the like and leak into the charge holding section 24 via the transfer section of the non-penetrating light shielding section 57B. Also, as shown by arrow B, the light incident on the photodiode 21 and reaching the non-penetrating light shielding section 57B may leak into the charge holding section 24 as diffracted light through the non-penetrating light shielding section 57B. The light leaking into the charge holding section 24 in this way becomes noise for the charge accumulated in the charge holding section 24.

[0073] Fig. 6 is a diagram illustrating an example of an arrangement of pixels 20 in a pixel array unit 11 according to an existing technique. In Fig. 6, pixel 20cn is a pixel arranged at a position corresponding to optical axis 61. Moreover, pixels 20ru, 20rd, 20lu, and 20ld are pixels arranged at the four corners of the pixel array unit 11, namely, the upper right, lower right, upper left, and lower left in Fig. 6, respectively.

[0074] 6, the pixels 20cn, 20ru, 20rd, 20lu, and 20ld are arranged in the pixel array section 11 with the direction in which the photodiode 21 and the charge holding section 24 are adjacent being uniform throughout the pixel array section 11. More specifically, in the figure, the charge holding section 24 is arranged in the upper part of the pixel 20, and the photodiode 21 is arranged toward the left side at the lower part of the pixel 20. That is, in the figure, the adjacent direction from the charge holding section 24 to the photodiode 21 of each of the pixels 20cn, 20ru, 20rd, 20lu, and 20ld is a diagonal direction diagonally downward and to the left.

[0075] In each of the pixels 20cn, 20ru, 20rd, 20lu, and 20ld, light incident on the pixel 20 is directed toward the light-condensing spots 70cn, 70ru, 70rd, 70lu, and 70ld, respectively, by the main lens 60. At this time, for example, in the pixels 20ru and 20rd arranged on the right side of the pixel array section 11, there is a possibility that the light incident on the photodiode 21 leaks into the charge holding section 24 via the transfer section of the non-penetrating light-shielding section 57B, as shown by arrows C and D, respectively.

[0076] On the other hand, in the pixels 20lu and 20ld arranged on the left side of the pixel array section 11, the light incident on the photodiode 21 is prevented from leaking into the charge holding section 24 by the penetrating light shielding section 57C.

[0077] It should be noted that by changing the light collection position of the main lens 60 along the direction of the optical axis 61, it is possible to improve to some extent the PLS (Parasitic Light Sensitivity) value, which indicates the noise components in the charge holding unit 24. However, when light is incident from the photodiode 21 toward a transfer unit that transfers charges to the charge holding unit 24, the PLS value deteriorates regardless of the light collection position.

[0078] In each embodiment of the present disclosure, each pixel 20 is arranged in the pixel array section 11 in an orientation according to its position in the pixel array section 11, thereby suppressing leakage of light from the photodiode 21 to the charge holding section 24.

[0079] In the following, the orientation of the pixel 20 is defined by the direction in which the photodiode 21 and the charge holding unit 24 are adjacent to each other. In Fig. 6, for example, in each pixel 20cn, the photodiode 21 is disposed toward the lower left of the pixel 20cn, and the photodiode 21 is adjacent to the charge holding unit 24 in a diagonally downward left direction. In this case, the pixel 20cn is considered to face in a diagonally downward left direction of the pixel array unit 11 in Fig. 6.

[0080] [3. First embodiment] Next, a first embodiment of the present disclosure will be described. Fig. 7 corresponds to Fig. 6 described above, and is a diagram that illustrates an example of an arrangement of pixels 20 in a pixel array section 11 according to the first embodiment. In the following description, the upper part of Fig. 7 is the upper part of the pixel array section 11.

[0081] In the first embodiment, the pixels 20 are arranged in the pixel array section 11 such that the positions of the photodiode 21 and the charge holding section 24 are symmetrical in the vertical and horizontal directions in the pixel array section 11.

[0082] That is, as shown in FIG. 7, the pixel 20ru in the upper right part of the pixel array section 11 is arranged with the charge holding section 24 at the bottom and the photodiode 21 at the upper right side. That is, the pixel 20ru is arranged in the pixel array section 11 facing a diagonally upward right direction. The pixel 20rd in the lower right part of the pixel array section 11 is arranged with the charge holding section 24 at the top and the photodiode 21 at the lower right side. That is, the pixel 20rd is arranged in the pixel array section 11 facing a diagonally downward right direction. The pixel 20lu in the upper left part of the pixel array section 11 is arranged with the charge holding section 24 at the bottom and the photodiode 21 at the upper left side. That is, the pixel 20lu is arranged in the pixel array section 11 facing a diagonally upward left direction. Also, the pixel 20ld in the lower left part of the pixel array section 11 is arranged with the charge holding section 24 at the top and the photodiode 21 at the lower left side. That is, the pixel 20ld is arranged in the pixel array section 11 facing a diagonally downward left direction.

[0083] 7, in other words, in each pixel 20, the photodiode 21 is disposed on the back side of the charge holding section 24 as viewed from the position of the optical axis 61. In this manner, by rotating the orientation of each pixel 20 in accordance with its position in the pixel array section 11 and disposing the photodiode 21 so as to be located on the back side of the charge holding section 24 as viewed from the position of the optical axis 61, it is possible to suppress leakage of light incident on the photodiode 21 into the charge holding section 24.

[0084] 8A and 8B are schematic diagrams showing a more specific example of the arrangement of the pixels 20 according to the first embodiment. For the sake of explanation, it is assumed here that the pixel array section 11 is arranged in a matrix of 6 pixels by 6 pixels, with the pixels 20 arranged in the matrix. It is also assumed that the optical axis 61 of the main lens 60 passes through the center of the pixel array section 11 perpendicularly to the light receiving surface of the pixel array section 11. A line passing through a position on the pixel array section 11 corresponding to the optical axis 61 (referred to as a position corresponding to the optical axis 61) in the column direction of the pixel array section 11 is referred to as a vertical center line, and similarly, a line passing through a position corresponding to the optical axis 61 in the row direction of the pixel array section 11 is referred to as a horizontal center line.

[0085] As shown in FIG. 8A, the pixel array unit 11 is divided into four regions that are vertically and horizontally symmetrical with respect to the position corresponding to the optical axis 61. Of the four regions, the upper left region is group #1, the upper right region is group #2, the lower left region is group #3, and the lower right region is group #4. In the example of FIG. 8A, each of the groups #1, #2, #3, and #4 includes pixels 201, 202, 203, and 204 in an array of 3 pixels by 3 pixels. The groups #1 and #3 and the groups #2 and #4 are arranged symmetrically with respect to the vertical center line. The groups #1 and #2 and the groups #3 and #4 are arranged symmetrically with respect to the horizontal center line.

[0086] 7, the photodiode 21 is disposed on the upper left side in the figure, and the charge retention portion 24 is disposed on the lower side. The non-penetrating light shielding portion 57B is provided on the lower side of the side that does not contact the charge retention portion 24 of the photodiode 21, and the penetrating light shielding portion 57C is provided on the upper side of the side and the side that contacts the charge retention portion 24 of the photodiode 21.

[0087] 7, the photodiode 21 is disposed on the upper right side in the figure, and the charge retention portion 24 is disposed on the lower side. The non-penetrating light shielding portion 57B is provided on the lower side of the side that does not contact the charge retention portion 24 of the photodiode 21, and the penetrating light shielding portion 57C is provided on the upper side of the side and the side that contacts the charge retention portion 24 of the photodiode 21.

[0088] 7, the photodiode 21 is disposed on the lower left side in the figure, and the charge retention portion 24 is disposed on the upper part. The non-penetrating light shielding portion 57B is provided on the upper side of the side that does not contact the charge retention portion 24 of the photodiode 21, and the penetrating light shielding portion 57C is provided on the lower side of the side and the side that contacts the charge retention portion 24 of the photodiode 21.

[0089] 7, the photodiode 21 is disposed on the lower right side in the figure, and the charge retention portion 24 is disposed on the upper part. The non-penetrating light shielding portion 57B is provided on the upper side of the side that does not contact the charge retention portion 24 of the photodiode 21, and the penetrating light shielding portion 57C is provided on the lower side of the side and the side that contacts the charge retention portion 24 of the photodiode 21.

[0090] Fig. 8B is a diagram illustrating the pixels 201-204 of each of groups #1-#4 in more detail, extracting the vicinity of the position of the optical axis 61 in Fig. 8A. Fig. 8B illustrates the third transfer gate portion 26, the reset transistor 27, the amplification transistor 28, and the selection transistor 29 included in each of the pixels 201-204. In the example of Fig. 8B, in each of the pixels 201-204, the third transfer gate portion 26 is disposed at the position of the charge holding portion 24, and the reset transistor 27, the amplification transistor 28, and the selection transistor 29 are disposed at the position of the photodiode 21.

[0091] 8B, the third transfer gate portion 26, the reset transistor 27, the amplification transistor 28, and the selection transistor 29 are asymmetrically disposed in each of the pixels 201 to 204. For example, in the pixel 201, the third transfer gate portion 26 is disposed close to the left end of the charge holding portion 24. Furthermore, with respect to the photodiode 21, the reset transistor 27 is disposed close to the lower left side, the amplification transistor 28 is disposed close to the upper center, and the selection transistor 29 is disposed close to the middle right side.

[0092] Here, the positional relationships of the third transfer gate portion 26, the reset transistor 27, the amplifying transistor 28 and the selection transistor 29, the photodiode 21 and the charge holding portion 24, as well as the non-penetrating light shielding portion 57B and the penetrating light shielding portion 57C within each of the pixels 201 to 204 included in each of the groups #1 to #4 are the same.

[0093] The positions of the third transfer gate portion 26, the reset transistor 27, the amplifying transistor 28, and the selection transistor 29 in the pixels 201 to 204 are merely an example, and the present invention is not limited to this example.

[0094] Taking the third transfer gate unit 26, the reset transistor 27, the amplification transistor 28, and the selection transistor 29 as an example, for example, in a pixel 202 included in group #2 located symmetrically to group #1 including pixel 201 with respect to the vertical center line, the third transfer gate unit 26, the reset transistor 27, the amplification transistor 28, and the selection transistor 29 are also disposed symmetrically to the third transfer gate unit 26, the reset transistor 27, the amplification transistor 28, and the selection transistor 29 of pixel 201 with respect to the vertical center line. That is, in pixel 202, the third transfer gate unit 26 is disposed close to the right end of the charge holding unit 24. Also, with respect to the photodiode 21, the reset transistor 27 is disposed close to the lower right side, the amplification transistor 28 is disposed close to the upper center, and the selection transistor 29 is disposed close to the middle left side.

[0095] On the other hand, in the pixel 203 included in the group #3 which is symmetrical to the group #1 with respect to the horizontal center line, the third transfer gate unit 26, the reset transistor 27, the amplification transistor 28, and the selection transistor 29 are also disposed symmetrically to the third transfer gate unit 26, the reset transistor 27, the amplification transistor 28, and the selection transistor 29 of the pixel 201 with respect to the horizontal center line. That is, in the pixel 203, the third transfer gate unit 26 is disposed close to the right end of the charge holding unit 24. Also, with respect to the photodiode 21, the reset transistor 27 is disposed close to the upper right side, the amplification transistor 28 is disposed close to the lower center, and the selection transistor 29 is disposed close to the middle left side.

[0096] Similarly, in the pixel 204 included in group #4 which is symmetrical to group #2 with respect to the horizontal center line, the third transfer gate unit 26, the reset transistor 27, the amplification transistor 28, and the selection transistor 29 are also disposed symmetrically to the third transfer gate unit 26, the reset transistor 27, the amplification transistor 28, and the selection transistor 29 of the pixel 201 with respect to the horizontal center line. That is, in the pixel 204, the third transfer gate unit 26 is disposed closer to the right end of the charge holding unit 24. Also, with respect to the photodiode 21, the reset transistor 27 is disposed closer to the upper right side, the amplification transistor 28 is disposed closer to the lower center, and the selection transistor 29 is disposed closer to the middle left side.

[0097] In this manner, in the first embodiment, the pixels 20 are arranged in the pixel array section 11 in a symmetrical direction with respect to the vertical center line and the horizontal center line of the pixel array section 11. At this time, in each pixel 20, the photodiode 21 is arranged so as to be located on the back side of the charge holding section 24 when viewed from a position corresponding to the optical axis 61 of the pixel array section 11. A surface light shielding section 57A is provided on the incident surface side of the charge holding section 24, and a through light shielding section 57C is provided between the charge holding section 24 and the photodiode 21. Therefore, it is possible to suppress leakage of light incident on the photodiode 21 into the charge holding section 24. Also, therefore, the CMOS image sensor 10 including the pixel array section 11 prevents a deterioration in the global shutter function due to leakage of light into the charge holding section 24.

[0098] (3-1. First Modification of the First Embodiment) Next, a first modified example of the first embodiment will be described. In the above-mentioned first embodiment, the pixel array section 11 is divided into four regions (groups #1 to #4) symmetrical with respect to the vertical center line and the horizontal center line, and the pixels 201 to 204 included in each of the four regions are arranged in a direction symmetrical with respect to the vertical center line and the horizontal center line. Therefore, in each of the pixels 201 to 204, the positional relationship between the photodiode 21 and the OCL 100 when viewed from the position of the optical axis 61 on the pixel array section 11 is different.

[0099] Specifically, in the column direction of the pixel array unit 11, two charge retention units 24 are arranged side by side in pixels 201 and 202, which are located at positions where groups #1 and #2 and groups #3 and #4 are adjacent, and in pixels 203 and 204. For example, in pixels 201 and 203, which are located on both sides of the horizontal center line, the charge retention unit 24 of pixel 201 and the charge retention unit 24 of pixel 203 are arranged side by side.

[0100] In addition, in the pixels 201 and 203 and the pixels 202 and 204 at positions where the groups #1 and #3 and the groups #2 and #4 contact in the row direction of the pixel array section 11, the photodiodes 21 are closer to positions facing each other.

[0101] With this arrangement, the distance between the photodiodes 21 of the pixels 201-204 across the vertical center line and the horizontal center line at the positions where the groups #1-#4 contact each other is longer than the distance between the photodiodes 21 of the pixels 201-204 in each of the groups #1-#4. This may cause discontinuity at the boundaries between the groups #1-#4 in an image based on pixel signals output from the pixel array section 11.

[0102] Therefore, in a first modification of the first embodiment, an optical waveguide for guiding light emitted from OCL 100 to photodiode 21 is provided between OCL 100 and photodiode 21 (semiconductor substrate 51). At this time, the surface of the optical waveguide in contact with OCL 100 (incident surface) has a size corresponding to OCL 100, and the surface in contact with semiconductor substrate 51 (exit surface) has a size corresponding to an opening for photodiode 21, and is connected to the opening.

[0103] 9A to 9C are schematic diagrams for explaining an optical waveguide according to a first modified example of the first embodiment. Fig. 9A corresponds to Fig. 8B described above, and shows how the OCLs 100 and the optical waveguides 801 to 804 are provided in a one-to-one correspondence with the pixels 201 to 204. Fig. 9B is a schematic cross-sectional view taken along line E-E' in the column direction in Fig. 9A, and Fig. 9C is a schematic cross-sectional view taken along line F-F' in the row direction in Fig. 9A.

[0104] Taking pixel 202 included in group #2 as an example, in the example of Fig. 9A, OCL 100 is provided so as to cover the entire incident surface of pixel 202. In this example, optical waveguide 802 has a mortar shape in which the cross-sectional area decreases stepwise from the incident surface to the exit surface, as shown in Fig. 9B and Fig. 9C.

[0105] The optical waveguide 802 is provided such that its bottom surface 812 substantially coincides in position and shape with the opening 104 for the photodiode 21 in the front-surface light-shielding portion 57A and contacts the semiconductor substrate 51 at the opening 104. That is, the optical waveguide 802 is provided such that its bottom surface 812 is positioned toward the upper right side of the pixel 202 in Fig. 9A (at a position toward the left side of the pixel 202 in Fig. 9B, which is a cross section in the column direction).

[0106] On the other hand, in pixel 204 included in group #4, optical waveguide 804 is provided with its bottom surface 814 positioned toward the right side of the lower portion of pixel 204 in FIG. 9A (positioned toward the right side of pixel 204 in FIG. 9B, which is a cross section in the column direction, and positioned toward the right side of pixel 204 in the example of FIG. 9C, which is a cross section in the row direction).

[0107] Similarly, in pixel 201 included in group #1, optical waveguide 801 is provided with its bottom surface positioned toward the upper left side of pixel 201 in Fig. 9A. In pixel 203 included in group #3, optical waveguide 803 is provided with its bottom surface 813 positioned toward the lower left side of pixel 203 in Fig. 9A (position toward the left side of pixel 203 in Fig. 9C, which is a cross section in the row direction).

[0108] The optical waveguides 801-804 are formed by being embedded in the protective film 103, and are made of a material having a higher refractive index than the protective film 103. For example, when the protective film 103 is made of SiO2, the optical waveguides 801-804 can be made of SiN, SiON, or the like.

[0109] 9A and 9B, the optical waveguides 801-804 are provided in the column direction of the pixel array section 11 so as to guide light to the rear side (i.e., the photodiode 21 side) of each of the pixels 201-204 as viewed from the horizontal center line. Similarly, as shown in Fig. 9A and 9C, the optical waveguides 801-804 are provided in the row direction of the pixel array section 11 so as to guide light to the rear side (i.e., the photodiode 21 side) of each of the pixels 201-204 as viewed from the vertical center line.

[0110] In this way, the pixels 201-204 included in each of the groups #1-#4 on the pixel array section 11 are subjected to pupil correction in a direction corresponding to the position on the pixel array section 11 by each of the optical waveguides 801-804. This makes it possible to correct variations in the incidence of light on the photodiode 21 when the pixels 201-204 are arranged facing in a direction corresponding to the position on the pixel array section 11.

[0111] (3-2. Second Modification of the First Embodiment) Next, a second modified example of the first embodiment will be described. As described above, in the first embodiment, the pixels 20 are rotated according to the groups #1 to #4 into which the pixel array section 11 is divided into four, and are arranged in different directions in each of the groups #1 to #4. Therefore, in the pixel array section 11, the intervals between the pixels 20 of the elements (the third transfer gate section 26, the reset transistor 27, the amplifying transistor 28, and the selection transistor 29) included in each pixel 20 aligned in the column direction and the row direction are no longer equal.

[0112] In the following description, when there is no need to particularly distinguish between the pixels 201 to 204, the pixels 201 to 204 will be represented by the pixel 20.

[0113] 8, for example, the third transfer gate section 26, the reset transistor 27, and the amplification transistor 28 are arranged toward one side in the row direction in the pixel 20. Therefore, the interval between the corresponding elements (the third transfer gate section 26, the reset transistor 27, and the amplification transistor 28) of the adjacent pixel 20 across the vertical center line is wider than the interval between the corresponding elements in the other pixels 20. On the other hand, the third transfer gate section 26 is arranged toward one side in the column direction (the lower side in the figure) in the pixel 20. Therefore, the interval between the corresponding elements (the third transfer gate section 26) of the adjacent pixel 20 across the horizontal center line is narrower than the interval between the corresponding elements in the other pixels 20. Due to this difference in the interval between the elements, the wiring capacitance of the wiring arranged along the row direction or column direction connected to the elements becomes non-uniform.

[0114] In the second modification of the first embodiment, the unevenness of the wiring capacitance caused by the difference in the spacing between the elements is suppressed by providing dummy wiring. Fig. 10 is a schematic diagram showing an example of wiring to each pixel according to the second modification of the first embodiment.

[0115] 10, the third transfer gate unit 26, the reset transistor 27, and the selection transistor 29 are supplied with drive signals TRG, RST, and SEL from the outside (vertical drive unit 12) via wiring arranged along the row direction. Specifically, the drive signal TRG is supplied to each third transfer gate unit 26 via wiring 92 arranged along the row direction. The drive signal SEL is supplied to each selection transistor 29 via wiring 91 arranged along the row direction. Note that in FIG. 10, to avoid complexity, the wiring that supplies the drive signal RST to each reset transistor 27 is omitted.

[0116] In addition, a power supply voltage V rst and V ddis supplied via wiring arranged in the column direction. A power supply voltage Vdd is supplied to each amplification transistor 28 via wiring 90 arranged in the column direction. In FIG. 10, in order to avoid complication, the power supply voltage V rst The wiring for supplying the reset transistors 27 is omitted.

[0117] Furthermore, the selection transistor 29 is connected to a vertical signal line 17 (VSL) arranged along the column direction, which transfers the read pixel signal to the outside (column processing unit 13).

[0118] 10, the third transfer gate unit 26 is spaced apart from the third transfer gate unit 26 of the adjacent pixel 20 across the vertical center line by a larger distance than the distance in the other pixels 20. Therefore, for example, a dummy wiring Dmy2 is provided in accordance with the difference in the distance for the wiring 92 arranged along the row direction that supplies the drive signal TRG to the third transfer gate unit 26. Also, the amplification transistor 28 is spaced apart from the amplification transistor 28 of the adjacent pixel 20 across the vertical center line by a larger distance than the distance in the other pixels 20. Therefore, when the power supply voltage V dd For example, a dummy wiring Dmy1 corresponding to the difference in the interval is provided for the wiring 90 arranged in the column direction, which supplies the amplifier transistor 28 with the signal.

[0119] On the other hand, in the example of Figure 10, the selection transistor 29 is arranged in approximately the center of the pixel 20 in the column direction, so that the spacing even in the portion straddling the horizontal center line is approximately the same as the spacing in other portions, and therefore no dummy wiring is provided for the vertical signal line 17 (VSL).

[0120] In this way, when each pixel 20 is rotated and arranged in a direction corresponding to its position on the pixel array section 11, unevenness in the wiring capacitance between elements occurs when dummy wiring is provided, so that unevenness in the wiring capacitance can be suppressed.

[0121] (3-3. Third Modification of the First Embodiment) Next, a third modified example of the first embodiment will be described. The third modified example of the first embodiment is another example of the arrangement of the non-penetrating light shielding portion 57B and the penetrating light shielding portion 57C in the pixel 20. Figures 11A and 11B are schematic diagrams of an example of the arrangement of the non-penetrating light shielding portion 57B and the penetrating light shielding portion 57C in the pixel 20 according to the third modified example of the first embodiment, as viewed from the incident surface side.

[0122] Here, the arrangement of non-penetrating light-shielding portion 57B and penetrating light-shielding portion 57C in pixel 20 described using Figure 5B is taken as a first example, and Figure 11A shows a second example of the arrangement, and Figure 11B shows a third example of the arrangement.

[0123] Fig. 11A is an example of pixel 20a in which non-penetrating light shielding portion 57B is provided in the center of one side that is not in contact with charge retention portion 24 of photodiode 21, and penetrating light shielding portion 57C is provided in the remaining portion. Fig. 11B is an example of pixel 20b in which non-penetrating light shielding portion 57B is provided at the end opposite to charge retention portion 24 of one side that is not in contact with charge retention portion 24 of photodiode 21, and penetrating light shielding portion 57C is provided in the remaining portion.

[0124] As already described, in the present disclosure, the pixels 20 are arranged in the pixel array section 11 so as to face in a direction corresponding to the position of the pixel array section 11. Therefore, in this manner, no matter where the non-penetrating light shielding section 57B for forming a transfer section that transfers charge from the photodiode 21 to the charge holding section 24 is arranged on the side of the photodiode 21 that is not in contact with the charge holding section 24, leakage of light from the photodiode 21 to the charge holding section 24 can be suppressed.

[0125] [4. Second embodiment] Next, a second embodiment of the present disclosure will be described. In the above-mentioned first embodiment, the arrangement of the pixels 20 on the pixel array section 11 is divided into four in the vertical and horizontal directions, and in each divided region, the pixels 20 are arranged facing a direction corresponding to the position of the region. In contrast, in the second embodiment, the arrangement of the pixels 20 on the pixel array section 11 is divided into two in the vertical or horizontal direction, and in each divided region, the pixels 20 are arranged facing a direction corresponding to the position of the region.

[0126] Fig. 12 is a schematic diagram showing a more specific example of the arrangement of the pixels 20 according to the second embodiment. For the sake of explanation, it is assumed in Fig. 12 that the pixel array unit 11 has a matrix arrangement of 4 pixels x 4 pixels, and the pixels 20 are arranged in the matrix arrangement.

[0127] In the example of Fig. 12, the pixel array section 11 is divided into two regions that are symmetrical vertically with respect to the position corresponding to the optical axis 61. That is, in Fig. 12, the pixel array section 11 is divided into two regions by the horizontal center line. Of the two regions, the upper region in Fig. 12 is group #5, and the lower region is group #6. In the example of Fig. 12, each of groups #5 and #6 includes pixels 205 and 206 in an array of 4 pixels x 2 pixels.

[0128] 7, the photodiode 21 is disposed on the upper left side in the figure, and the charge retention portion 24 is disposed on the lower side. In the pixel 205, the non-penetrating light shielding portion 57B is provided on the lower side of the side that does not contact the charge retention portion 24 of the photodiode 21, and the penetrating light shielding portion 57C is provided on the upper side of the side and the side that contacts the charge retention portion 24 of the photodiode 21.

[0129] 7, the photodiode 21 is disposed on the lower left side in the figure, and the charge retention portion 24 is disposed on the upper part. In the pixel 206, the non-penetrating light shielding portion 57B is provided on the upper side of the side that does not contact the charge retention portion 24 of the photodiode 21, and the penetrating light shielding portion 57C is provided on the lower side of the side and the side that contacts the charge retention portion 24 of the photodiode 21.

[0130] 12, the photodiode 21 is disposed so as to be located on the rear side of the charge holding unit 24 when viewed from a position corresponding to the optical axis 61 of the pixel array unit 11. This makes it possible to suppress leakage of light incident on the photodiode 21 into the charge holding unit 24. This also makes it possible to prevent degradation of the global shutter function of the CMOS image sensor 10 including the pixel array unit 11 due to leakage of light into the charge holding unit 24.

[0131] Even if the pixel array section 11 is divided into two regions in this manner, by arranging the pixel 20 in a direction corresponding to its position on the pixel array section 11, it is possible to suppress leakage of light incident on the photodiode 21 into the charge holding section 24.

[0132] 12, for example, in each pixel 206 included in group #6, the photodiode 21 is disposed on the lower left side in the figure, and the charge storage unit 24 is disposed on the upper part, but this is not limited to this example. For example, each pixel 206 in group #6 may have the photodiode 21 disposed on the lower right side in the figure, and the charge storage unit 24 disposed on the upper part.

[0133] (4-1. Modification of the second embodiment) Next, a modified example of the second embodiment will be described. In the modified example of the second embodiment, similarly to the first modified example of the first embodiment described above, an optical waveguide for guiding light emitted from the OCL 100 to the photodiode 21 is provided between the OCL 100 and the photodiode 21 (semiconductor substrate 51).

[0134] Fig. 13A to Fig. 13C are schematic diagrams for explaining an optical waveguide according to a modified example of the second embodiment. Fig. 13A corresponds to Fig. 9A described above, and shows how each OCL 100 and each optical waveguide 805 and 806 are provided in a one-to-one correspondence with each of the pixels 205 and 206. Fig. 13B is a schematic cross-sectional view taken along line G-G' in the column direction in Fig. 13A, and Fig. 13C is a schematic cross-sectional view taken along line H-H' in the row direction in Fig. 13A.

[0135] The positional relationship between the OCL 100, the optical waveguides 805 and 806, and the photodiode 21 is the same as in the first modification of the first embodiment described above.

[0136] Taking pixel 206 included in group #6 as an example, OCL 100 is provided so as to cover the entire incident surface of pixel 206. Also, as shown in Figures 13B and 13C, optical waveguide 806 has a mortar shape in which the cross-sectional area decreases stepwise from the incident surface to the exit surface.

[0137] The optical waveguide 806 is provided such that its bottom surface 816 substantially coincides in position and shape with the opening 104 for the photodiode 21 in the front-surface light-shielding portion 57A and contacts the semiconductor substrate 51 at the opening 104. That is, the optical waveguide 806 is provided such that its bottom surface 816 is positioned toward the upper right side of the pixel 206 in Fig. 13A (a position toward the right side of the pixel 206 in Fig. 13B which is a cross section in the column direction, and a position toward the left side of the pixel 206 in Fig. 13C which is a cross section in the row direction).

[0138] On the other hand, in the pixel 205 included in group #5, the optical waveguide 805 has its bottom surface 815 positioned toward the lower right side of the pixel 205 in FIG. 13A (to the right side of the pixel 205 in FIG. 13B, which is a cross section in the column direction).

[0139] In this way, even if the arrangement of the pixels 20 on the pixel array section 11 is divided into two in the vertical or horizontal direction, each of the pixels 205 and 206 included in each of the groups #5 to #6 on the pixel array section 11 undergoes pupil correction in a direction according to the position on the pixel array section 11 by each of the optical waveguides 805 and 806. This makes it possible to correct the variation in the incidence of light on the photodiode 21 when each of the pixels 205 to 206 is arranged facing a direction according to the position on the pixel array section 11.

[0140] [5. Third embodiment] Next, a third embodiment of the present disclosure will be described. The third embodiment of the present disclosure is an example in which the solid-state imaging device according to the first embodiment, the second embodiment, and each of the modified examples thereof is applied to an electronic device.

[0141] Fig. 14 is a block diagram showing a schematic configuration of an example of an imaging device as an electronic device according to the third embodiment. In Fig. 14, the imaging device 1000 includes an imaging optical system 1001 including a lens group and the like, an imaging unit 1002, a DSP circuit 1003, a frame memory 1004, a display device 1005, a recording device 1006, an operation system 1007, and a power supply system 1008. The DSP circuit 1003, the frame memory 1004, the display device 1005, the recording device 1006, the operation system 1007, and the power supply system 1008 are connected to each other via a bus line 1009.

[0142] The imaging optical system 1001 captures incident light (image light) from a subject and forms an image on the imaging surface of the imaging unit 1002. The imaging unit 1002 converts the amount of incident light imaged on the imaging surface by the imaging optical system 1001 into an electrical signal on a pixel-by-pixel basis and outputs the signal as a pixel signal. A DSP (Digital Signal Processor) circuit 1003 performs general camera signal processing, such as white balance processing, demosaic processing, and gamma correction processing.

[0143] The frame memory 1004 is used to store data as appropriate during signal processing in the DSP circuit 1003. The display device 1005 can be a panel-type display device such as a liquid crystal display device or an organic EL (electro luminescence) display device, and displays moving images or still images captured by the imaging unit 1002. The recording device 1006 records the moving images or still images captured by the imaging unit 1002 in a recording medium such as a portable semiconductor memory, an optical disc, or an HDD (Hard Disk Drive).

[0144] In response to operations by a user, an operation system 1007 issues operation commands for various functions of the imaging device 1000. A power supply system 1008 appropriately supplies various types of power to these devices as operating power sources for the DSP circuit 1003, frame memory 1004, display device 1005, recording device 1006, and operation system 1007.

[0145] In the imaging device 1000 having the above-mentioned configuration, the CMOS image sensor 10 to which the technology according to the present disclosure is applied can be used as the imaging unit 1002. According to the CMOS image sensor 10 to which the technology according to the present disclosure is applied, in a back-illuminated type having a charge retention unit 24, it is possible to suppress incidence of light into the charge retention unit 24, thereby obtaining a captured image with low noise and high image quality.

[0146] [6. Fourth embodiment] Next, as a fourth embodiment, an application example of the CMOS image sensor 10 according to the first and second embodiments and their respective modified examples according to the present disclosure will be described. Fig. 15 is a diagram showing a usage example of the CMOS image sensor 10 according to the above-mentioned first and second embodiments and their respective modified examples.

[0147] The above-described CMOS image sensor 10 can be used in various cases for sensing light such as visible light, infrared light, ultraviolet light, and X-rays, for example, as described below.

[0148] -Digital cameras, mobile devices with camera functions, and other devices that take images for viewing. Devices used for traffic purposes, such as on-board sensors that photograph the front, rear, surroundings, and interior of a vehicle for safe driving such as automatic stopping, and for recognition of the driver's condition, surveillance cameras that monitor moving vehicles and roads, and distance measuring sensors that measure distances between vehicles. A device used in home appliances such as TVs, refrigerators, and air conditioners to capture user gestures and operate the appliance in accordance with those gestures. - Equipment used for medical or healthcare purposes, such as endoscopes and devices that take blood vessel images by receiving infrared light. - Equipment used for security purposes, such as surveillance cameras for crime prevention and cameras for person authentication. - Equipment used for beauty purposes, such as skin measuring devices that take pictures of the skin and microscopes that take pictures of the scalp. Equipment used for sports, such as action cameras and wearable cameras for sports purposes. Agricultural equipment, such as cameras for monitoring fields and crop conditions.

[0149] [Further application examples of the technology disclosed herein] (6-1. Application examples for endoscopic surgery systems) The technology according to the present disclosure (the technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0150] FIG. 16 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

[0151] 16 shows a state in which an operator (doctor) 11131 is performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0152] The endoscope 11100 is composed of a lens barrel 11101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the illustrated example, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may be configured as a so-called flexible scope having a flexible lens barrel.

[0153] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens toward an observation target in the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0154] An optical system and an image sensor are provided inside the camera head 11102, and reflected light (observation light) from an observation target is collected on the image sensor by the optical system. The observation light is photoelectrically converted by the image sensor to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to an observation image. The image signal is transmitted to a camera control unit (CCU) 11201 as RAW data.

[0155] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and performs overall control of the operations of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102, and performs various types of image processing on the image signal, such as development processing (demosaic processing), for displaying an image based on the image signal.

[0156] Under the control of the CCU 11201, the display device 11202 displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

[0157] The light source device 11203 is composed of a light source such as an LED (Light Emitting Diode), and supplies the endoscope 11100 with irradiation light when photographing an operation site or the like.

[0158] The input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to change the imaging conditions (type of irradiated light, magnification, focal length, etc.) of the endoscope 11100.

[0159] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 sends gas into the body cavity of the patient 11132 via the insufflation tube 11111 to inflate the body cavity for the purpose of securing the field of view of the endoscope 11100 and securing the working space of the surgeon. The recorder 11207 is a device capable of recording various information related to the surgery. The printer 11208 is a device capable of printing various information related to the surgery in various formats such as text, image, or graph.

[0160] The light source device 11203 that supplies irradiation light to the endoscope 11100 when photographing the surgical site can be composed of a white light source composed of, for example, an LED, a laser light source, or a combination of these. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so that the white balance of the captured image can be adjusted in the light source device 11203. In this case, it is also possible to capture images corresponding to each of the RGB colors in a time-division manner by irradiating the observation object with laser light from each of the RGB laser light sources in a time-division manner and controlling the driving of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter to the image sensor.

[0161] The light source device 11203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. The driving of the image sensor of the camera head 11102 may be controlled in synchronization with the timing of the change in the light intensity to obtain images in a time-division manner, and the images may be synthesized to generate an image with a high dynamic range that is free of so-called blackout and whiteout.

[0162] The light source device 11203 may be configured to supply light of a predetermined wavelength band corresponding to the special light observation. In the special light observation, for example, by utilizing the wavelength dependency of light absorption in body tissue, a narrow band light is irradiated compared to the irradiated light (i.e., white light) during normal observation, and a predetermined tissue such as blood vessels on the mucous membrane surface is photographed with high contrast, so-called narrow band imaging is performed. Alternatively, in the special light observation, a fluorescent observation may be performed in which an image is obtained by fluorescence generated by irradiating an excitation light. In the fluorescent observation, it is possible to irradiate an excitation light to a body tissue and observe the fluorescence from the body tissue (autofluorescence observation), or to locally inject a reagent such as indocyanine green (ICG) into the body tissue and irradiate the body tissue with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 11203 may be configured to supply narrow band light and / or excitation light corresponding to such special light observation.

[0163] FIG. 17 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0164] The camera head 11102 has a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 has a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other by a transmission cable 11400 so as to be able to communicate with each other.

[0165] The lens unit 11401 is an optical system provided at the connection portion with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is configured by combining a plurality of lenses including a zoom lens and a focus lens.

[0166] The imaging unit 11402 is composed of an imaging element. The imaging element constituting the imaging unit 11402 may be one (so-called single-plate type) or multiple (so-called multi-plate type). When the imaging unit 11402 is composed of a multi-plate type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining the image signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to 3D (Dimensional) display. By performing 3D display, the surgeon 11131 can more accurately grasp the depth of the biological tissue in the surgical site. Note that when the imaging unit 11402 is composed of a multi-plate type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0167] Furthermore, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the lens barrel 11101, immediately behind the objective lens.

[0168] The driving unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be appropriately adjusted.

[0169] The communication unit 11404 is configured by a communication device for transmitting and receiving various information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0170] Furthermore, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201, and supplies the control signal to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of capturing the image, and / or information specifying the magnification and focus of the captured image.

[0171] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by a user, or may be automatically set by the control unit 11413 of the CCU 11201 based on an acquired image signal. In the latter case, the endoscope 11100 is equipped with a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0172] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 via the communication unit 11404.

[0173] The communication unit 11411 is configured with a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0174] Furthermore, the communication unit 11411 transmits, to the camera head 11102, a control signal for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

[0175] The image processing unit 11412 performs various types of image processing on the image signal, which is RAW data sent from the camera head 11102 .

[0176] The control unit 11413 performs various controls related to imaging of the surgical site etc. by the endoscope 11100 and display of the captured image obtained by imaging the surgical site etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0177] Further, the control unit 11413 causes the display device 11202 to display the captured image showing the surgical site, etc., based on the image signal that has been image-processed by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition techniques. For example, the control unit 11413 can recognize surgical tools such as forceps, specific living body parts, bleeding, mist when the energy treatment tool 11112 is used, etc., by detecting the shape and color of the edge of an object included in the captured image. When the control unit 11413 causes the display device 11202 to display the captured image, it may use the recognition result to superimpose various types of surgery support information on the image of the surgical site. By superimposing and presenting the surgery support information to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

[0178] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for communication of electrical signals, an optical fiber for optical communication, or a composite cable of these.

[0179] Here, in the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0180] An example of an endoscopic surgery system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to, for example, the lens unit 11401 and the imaging unit 11402 of the camera head 11102 among the above-described configurations. This enables the captured image to have low noise and high image quality, and a clearer image of the surgical site can be obtained, allowing the surgeon to reliably check the surgical site.

[0181] (6-2. Application examples to moving objects) The technology according to the present disclosure can be further applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving object, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, or a robot.

[0182] FIG. 18 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a moving object control system to which the technology according to the present disclosure can be applied.

[0183] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 18, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also, as functional configurations of the integrated control unit 12050, a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053 are illustrated.

[0184] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0185] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as head lamps, back lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves or signals of various switches transmitted from a portable device that replaces a key may be input to the body system control unit 12020. The body system control unit 12020 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, and the like of the vehicle.

[0186] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture an image outside the vehicle and receives the captured image. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for a person, a car, an obstacle, a sign, or characters on a road surface, based on the received image.

[0187] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according to the amount of light received. The imaging unit 12031 can output the electrical signal as an image, or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0188] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing.

[0189] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, the steering mechanism, or the braking device based on the information inside and outside the vehicle acquired by the outside-of-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output a control command to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0190] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on the driver's operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle acquired by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0191] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside-vehicle information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside-vehicle information detection unit 12030, and perform cooperative control for the purpose of preventing glare, such as switching from high beams to low beams.

[0192] The audio / video output unit 12052 transmits at least one output signal of audio and video to an output device capable of visually or audibly notifying information to passengers in the vehicle or the outside of the vehicle. In the example of Fig. 18, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are exemplified as the output device. The display unit 12062 may include at least one of an on-board display and a head-up display, for example.

[0193] FIG. 19 is a diagram showing an example of the installation position of the imaging unit 12031.

[0194] In FIG. 19, a vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as an imaging unit 12031.

[0195] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided at positions such as the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided at the front nose and the imaging unit 12105 provided at the upper part of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided at the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided at the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The images of the front acquired by the imaging units 12101 and 12105 are mainly used to detect a preceding vehicle, a pedestrian, an obstacle, a traffic light, a traffic sign, a lane, or the like.

[0196] 19 shows an example of the imaging ranges of the imaging units 12101 to 12104. An imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and an imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, an overhead image of the vehicle 12100 viewed from above is obtained by superimposing the image data captured by the imaging units 12101 to 12104.

[0197] At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera made up of a plurality of imaging elements, or may be an imaging element having pixels for detecting a phase difference.

[0198] For example, the microcomputer 12051 can extract, as a preceding vehicle, a three-dimensional object that is the closest three-dimensional object on the travel path of the vehicle 12100 and travels at a predetermined speed (for example, 0 km / h or more) in approximately the same direction as the vehicle 12100, by calculating the distance to each three-dimensional object in the imaging ranges 12111 to 12114 and the change over time of this distance (relative speed with respect to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104. Furthermore, the microcomputer 12051 can set a vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including follow-up stop control) and automatic acceleration control (including follow-up start control). In this way, cooperative control can be performed for the purpose of automatic driving that travels autonomously without relying on the driver's operation.

[0199] For example, the microcomputer 12051 classifies and extracts three-dimensional object data on three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. Then, the microcomputer 12051 determines a collision risk indicating the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0200] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not a pedestrian is present in the captured images of the imaging units 12101 to 12104. The recognition of such a pedestrian is performed, for example, by a procedure of extracting feature points in the captured images of the imaging units 12101 to 12104 as infrared cameras, and a procedure of performing pattern matching processing on a series of feature points that indicate the contour of an object to determine whether or not the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the captured images of the imaging units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

[0201] An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to, for example, the imaging unit 12031 among the above-described configurations. By applying the technology according to the present disclosure to the imaging unit 12031, it is possible to reduce noise and improve image quality of the captured image, and it is possible to obtain a captured image that is easier to see, thereby reducing the fatigue of the driver.

[0202] The present technology can also be configured as follows. (1) a photoelectric conversion unit that converts light into an electric charge by photoelectric conversion; a charge accumulation section adjacent to the photoelectric conversion section and configured to accumulate the charge transferred from the photoelectric conversion section; a pixel array in which pixels including The pixel is The photoelectric conversion unit is disposed in the pixel array such that a direction in which the photoelectric conversion unit is adjacent to the charge accumulation unit is oriented in a direction corresponding to the position of the photoelectric conversion unit in the pixel array. Solid-state imaging element. (2) The pixel is the photoelectric conversion unit is disposed in the pixel array so as to face a direction in which the photoelectric conversion unit is positioned outside the pixel array with respect to the charge accumulation unit; The solid-state imaging device according to (1) above. (3) Each of the pixels included in the pixel array has the photoelectric conversion unit is disposed so that a direction in which the photoelectric conversion unit is adjacent to the charge accumulation unit is symmetrical with respect to a first line passing through a predetermined position of the pixel array; The solid-state imaging device according to (1) or (2). (4) Each of the pixels included in the pixel array has and arranged in a direction further symmetrical with respect to a second line perpendicular to the first line at the predetermined position of the pixel array. The solid-state imaging device according to (3) above. (5) the predetermined position is a substantially central position in the arrangement of the pixel array, The solid-state imaging device according to (3) or (4). (6) The predetermined position is A position corresponding to an optical axis of a lens for irradiating light onto a light receiving surface of the pixel array, The solid-state imaging device according to any one of (3) to (5). (7) The pixel is a trench light shielding portion that is dug down from an irradiation surface side where light is irradiated in the pixel, on an outer periphery of the photoelectric conversion portion; The trench light shielding portion is In the pixel, a part of the pixel is a non-penetrating part that does not penetrate from the irradiation surface to a surface opposite to the irradiation surface, and the remaining part is a penetrating part that penetrates the pixel. The solid-state imaging device according to any one of (1) to (6). (8) The non-penetrating portion is the trench light-shielding portion is provided on a side of the periphery of the photoelectric conversion portion that is not adjacent to the charge accumulation portion and does not constitute a side of the periphery of the pixel, The solid-state imaging device according to (7) above. (9) The non-penetrating portion is provided on the side of the charge storage unit, The solid-state imaging device according to (8) above. (10) The non-penetrating portion is Provided at the center portion of the side, The solid-state imaging device according to (8) above. (11) The non-penetrating portion is The charge accumulation portion is provided on the side opposite to the side where the charge accumulation portion is provided. The solid-state imaging device according to (8) above. (12) The pixel array includes: The pixel array further includes wiring connected to an element for driving the pixels included in each of the pixels aligned in a row direction or a column direction of the pixel array, The wiring is a dummy wiring corresponding to a difference between a distance between the elements corresponding to each other included in a first pixel and a second pixel that are arranged adjacent to each other and facing different directions in the alignment direction among the pixels, and a distance between the first pixels adjacent to each other or a distance between the second pixels adjacent to each other; The solid-state imaging device according to any one of (1) to (11) above. (13) The pixel is Further comprising an optical waveguide for guiding light incident on the first surface to the photoelectric conversion unit, The optical waveguide is the first surface has a shape corresponding to an irradiation section through which light is irradiated onto the pixel, the second surface from which light incident from the first surface is emitted has a shape corresponding to an incident section through which light is incident onto the photoelectric conversion section, and the second surface is connected to the incident section. The solid-state imaging device according to any one of (1) to (12) above. (14) A lens is provided for the first surface of the optical waveguide. The solid-state imaging device according to (13) above. (15) a photoelectric conversion unit that converts light into an electric charge by photoelectric conversion; a charge accumulation section adjacent to the photoelectric conversion section and configured to accumulate the charge transferred from the photoelectric conversion section; a pixel array in which pixels including a solid-state imaging element in which the pixels are arranged with respect to the pixel array such that a direction in which the photoelectric conversion unit is adjacent to the charge accumulation unit is oriented in a direction corresponding to a position within the pixel array; a signal processing unit that performs signal processing on pixel signals read from the solid-state imaging device to generate image data; a storage unit that stores the image data generated by the signal processing unit; An electronic device having the [Explanation of symbols]

[0203] 10 CMOS image sensor 11 Pixel array section 12 Vertical drive unit 13 Column processing section 17 Vertical signal line 20,201,202,203,204,205,206,20a,20b,20cn,20ld,20lu,20rd,20ru pixels 21 Photodiode 24 Charge holding section 26 Third transfer gate section 27 Reset transistor 28 Amplifying transistor 29 Select transistor 51 Semiconductor Substrate 54,111 wiring layer 57B Non-penetrating light shielding part 57C Penetration light shielding part 60 Primary Lens 61 Optical axis 801,802,803,804,805,806 optical waveguide 90,91,92 Wiring 100 OCL 1000 Imaging device

Claims

1. a photoelectric conversion unit that converts light into an electric charge by photoelectric conversion; a charge accumulation section adjacent to the photoelectric conversion section and configured to accumulate the charge transferred from the photoelectric conversion section; a pixel array in which pixels including The pixel is The photoelectric conversion unit is disposed with respect to the pixel array such that a direction in which the photoelectric conversion unit is adjacent to the charge accumulation unit corresponds to a position in the pixel array, and the photoelectric conversion unit is disposed with respect to the charge accumulation unit so as to face a direction in which the photoelectric conversion unit is located outside the pixel array with respect to the charge accumulation unit. Solid-state imaging element.

2. Each of the pixels included in the pixel array has the photoelectric conversion unit is disposed so that a direction in which the photoelectric conversion unit is adjacent to the charge accumulation unit is symmetrical with respect to a first line passing through a predetermined position of the pixel array; The solid-state imaging device according to claim 1 .

3. Each of the pixels included in the pixel array has the first line is disposed at the predetermined position of the pixel array in a direction that is further symmetrical with respect to a second line perpendicular to the first line; The solid-state imaging device according to claim 2 .

4. the predetermined position is a substantially central position in the arrangement of the pixel array, The solid-state imaging device according to claim 2 .

5. The predetermined position is A position corresponding to an optical axis of a lens for irradiating light onto a light receiving surface of the pixel array, The solid-state imaging device according to claim 2 .

6. The pixel is a trench light shielding portion that is dug down from an irradiation surface side where light is irradiated in the pixel, on an outer periphery of the photoelectric conversion portion; The trench light shielding portion is In the pixel, a part of the pixel is a non-penetrating part that does not penetrate from the irradiation surface to a surface opposite to the irradiation surface, and the remaining part is a penetrating part that penetrates the pixel. The solid-state imaging device according to claim 1 .

7. The non-penetrating portion is the trench light-shielding portion is provided on a side of the periphery of the photoelectric conversion portion that is not adjacent to the charge accumulation portion and does not constitute a side of the periphery of the pixel, The solid-state imaging device according to claim 6 .

8. The non-penetrating portion is provided on the side of the charge storage unit, The solid-state imaging device according to claim 7 .

9. The non-penetrating portion is Provided at the center portion of the side, The solid-state imaging device according to claim 7 .

10. The non-penetrating portion is The charge accumulation portion is provided on the side opposite to the side where the charge accumulation portion is provided. The solid-state imaging device according to claim 7 .

11. The pixel array includes: The pixel array further includes wiring connected to an element for driving the pixels included in each of the pixels aligned in a row direction or a column direction of the pixel array, The wiring is a dummy wiring corresponding to a difference between a distance between the elements corresponding to each other included in a first pixel and a second pixel that are arranged adjacent to each other and facing different directions in the alignment direction, and a distance between the first pixels adjacent to each other or a distance between the second pixels adjacent to each other; The solid-state imaging device according to claim 1 .

12. The pixel is Further comprising an optical waveguide for guiding light incident on the first surface to the photoelectric conversion unit; The optical waveguide is the first surface has a shape corresponding to an irradiation portion through which the pixel is irradiated with light, the second surface from which the light incident from the first surface is emitted has a shape corresponding to an incident portion through which the light is incident on the photoelectric conversion portion, and the second surface is connected to the incident portion; The solid-state imaging device according to claim 1 .

13. A lens is provided for the first surface of the optical waveguide. The solid-state imaging device according to claim 12.

14. a photoelectric conversion unit that converts light into an electric charge by photoelectric conversion; a charge accumulation section adjacent to the photoelectric conversion section and configured to accumulate the charge transferred from the photoelectric conversion section; a pixel array in which pixels including a solid-state imaging element in which the pixels are arranged with respect to the pixel array such that a direction in which the photoelectric conversion unit is adjacent to the charge accumulation unit corresponds to a position in the pixel array, and the photoelectric conversion unit is positioned outside the pixel array with respect to the charge accumulation unit; a signal processing unit that performs signal processing on pixel signals read from the solid-state imaging device to generate image data; a storage unit that stores the image data generated by the signal processing unit; An electronic device having the

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