Light detection device and electronic apparatus

Abstract

To provide a light detection device capable of realizing a desired pixel characteristic while suppressing generation of dark current.SOLUTION: A light detection device comprises: a semiconductor substrate; a plurality of photoelectric conversion units formed in a two-dimensional array on the semiconductor substrate; and an inter-pixel separation structure formed in a region between the photoelectric conversion units of the semiconductor substrate. The inter-pixel separation structure includes: a first inter-pixel separation structure that is a part in an effective pixel region; and a second inter-pixel separation structure that is a part in a light-shielding pixel region surrounding a circumference of the effective pixel region. In the first inter-pixel separation structure, a first conductor is arranged. In the second inter-pixel separation structure, a second conductor which is electrically connected to the first conductor, and to which a negative bias voltage is applied is arranged. In addition, the first and second conductors are formed using different conductive materials.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present technology (technology related to the present disclosure) relates to a light detection device and an electronic device. [Background technology]

[0002] Conventionally, for example, a photodetector has been proposed that includes a semiconductor substrate having a plurality of photoelectric conversion units, a trench portion formed in a region between the photoelectric conversion units of the semiconductor substrate, and an inter-pixel isolation structure having a conductor disposed in the trench portion (see, for example, Patent Document 1). In the photodetector described in Patent Document 1, a negative bias voltage is applied to the conductor to bring the peripheral portion of the inter-pixel isolation structure into a high hole concentration state, thereby suppressing the generation of dark current. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-148841 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a photodetector, it is required to suppress the generation of dark current and also to make it possible to realize desired pixel characteristics.

[0005] An object of the present disclosure is to provide a photodetector and electronic device capable of realizing desired pixel characteristics while suppressing the generation of dark current. [Means for solving the problem]

[0006] The photodetection device disclosed herein comprises (a) a semiconductor substrate; (b) a plurality of photoelectric conversion units formed in a two-dimensional array on the semiconductor substrate; and (c) an inter-pixel isolation structure formed in a region between the photoelectric conversion units on the semiconductor substrate, (d) the inter-pixel isolation structure has a first inter-pixel isolation structure which is a portion within an effective pixel region and a second inter-pixel isolation structure which is a portion within a light-shielding pixel region surrounding the effective pixel region, (e) a first conductor is disposed within the first inter-pixel isolation structure, (f) a second conductor is disposed within the second inter-pixel isolation structure and is electrically connected to the first conductor and has a negative bias voltage applied thereto, and (g) the first conductor and the second conductor are formed using different conductive materials.

[0007] The electronic device disclosed herein comprises (a) a semiconductor substrate, (b) a plurality of photoelectric conversion units formed in a two-dimensional array on the semiconductor substrate, (c) and an inter-pixel isolation structure formed in a region between the photoelectric conversion units of the semiconductor substrate, (d) the inter-pixel isolation structure has a first inter-pixel isolation structure which is a portion within an effective pixel region and a second inter-pixel isolation structure which is a portion within a light-shielded pixel region surrounding the effective pixel region, (e) a first conductor is disposed within the first inter-pixel isolation structure, (f) a second conductor is disposed within the second inter-pixel isolation structure and is electrically connected to the first conductor and has a negative bias voltage applied thereto, and (g) a photodetector device in which the first conductor and the second conductor are formed using different conductive materials. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing an overall configuration of a solid-state imaging device according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing a planar configuration of one of the four corners of a pixel area. [Diagram 3] 3 is a diagram showing a cross-sectional configuration of the solid-state imaging device taken along line AA in FIG. 2. FIG. [Figure 4] 3 is a diagram showing a cross-sectional configuration of the solid-state imaging device taken along line BB in FIG. 2. [Diagram 5] 1A to 1C are diagrams illustrating a method for manufacturing a solid-state imaging device. [Figure 6] 1A to 1C are diagrams illustrating a method for manufacturing a solid-state imaging device. [Figure 7] 1A to 1C are diagrams illustrating a method for manufacturing a solid-state imaging device. [Figure 8] 1A to 1C are diagrams illustrating a method for manufacturing a solid-state imaging device. [Figure 9] 1A to 1C are diagrams illustrating a method for manufacturing a solid-state imaging device. [Figure 10] 13 is a diagram showing a planar configuration of one of the four corners of a pixel region 2 of a solid-state imaging device according to a second embodiment. FIG. [Figure 11] 11 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a second embodiment when cut along line CC in FIG. [Figure 12] 11 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a second embodiment when cut along line DD in FIG. [Figure 13] 3 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a third embodiment, taken along line AA in FIG. 2. FIG. [Figure 14] 3 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a third embodiment when cut along line BB in FIG. 2. [Figure 15] FIG. 13 is a diagram showing a schematic configuration of an electronic device according to a fourth embodiment. [Figure 16] FIG. 1 is a diagram illustrating an example of a schematic configuration of an endoscope system. [Figure 17] 17 is a block diagram showing an example of a functional configuration of the camera and the CCU shown in FIG. 16. [Figure 18] FIG. 1 is a diagram illustrating an example of a schematic configuration of a microsurgery system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An example of a light detection device and an electronic device according to an embodiment of the present disclosure will be described below with reference to FIGS. 1 to 18. The embodiment of the present disclosure will be described in the following order. Note that the present disclosure is not limited to the following example. Also, the effects described in this specification are merely examples and are not limiting, and other effects may be present.

[0010] 1. First embodiment: solid-state imaging device 1-1 Overall configuration of solid-state imaging device 1-2 Main components 1-3 Manufacturing method of solid-state imaging device 2. Second embodiment: Solid-state imaging device 2-1 Main components 3. Third embodiment: Solid-state imaging device 3-1 Main components 3-2 Variations 4. Fourth embodiment: Application to electronic devices 5. Fifth embodiment: Application to a moving object

[0011] 1. First embodiment [1-1 Overall configuration of solid-state imaging device] A solid-state imaging device 1 (or, in a broader sense, a "photodetector") according to a first embodiment of the present disclosure will be described below. Fig. 1 is a diagram showing the overall configuration of the solid-state imaging device 1 according to the first embodiment. The solid-state imaging device 1 in Fig. 1 is a back-illuminated CMOS (Complementary Metal Oxide Semiconductor) image sensor. As shown in Fig. 15, the solid-state imaging device 1 (1002) captures image light (incident light) from a subject via a lens group 1001, converts the amount of incident light focused on an imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs the electrical signal. As shown in FIG. 1, the solid-state imaging device 1 includes a pixel region 2, a vertical drive circuit 3, a column signal processing circuit 4, a horizontal drive circuit 5, an output circuit 6, and a control circuit .

[0012] The pixel region 2 has a plurality of pixels 8 arranged in a two-dimensional array. Each pixel 8 has a photoelectric conversion unit PD (see FIG. 3) and a plurality of pixel transistors (e.g., a transfer transistor, a reset transistor, an amplification transistor, and a selection transistor). As shown in FIG. 2, the pixel region 2 includes an effective pixel region 12 and a light-shielded pixel region 13 located around the effective pixel region 12. The light-shielded pixel region 13 has, as light-shielded pixels, OPB (Optical Black) pixels and dummy pixels for obtaining a reference signal of an optical black level. The vertical drive circuit 3 is configured, for example, by a shift register, and sequentially selects each pixel 8 in the pixel region 2 on a row-by-row basis by, for example, sequentially outputting selection pulses to pixel drive wiring 9, and outputs pixel signals of the selected pixels 8 to the column signal processing circuit 4 through vertical signal lines 10. Examples of pixel signals include signals obtained from charges (for example, electrons) generated in the photoelectric conversion unit PD.

[0013] The column signal processing circuit 4 is arranged, for example, for each column of pixels 8, and performs signal processing such as noise removal for each pixel column on signals output from one row of pixels 8. For the signal processing, for example, correlated double sampling (CDS) for removing fixed pattern noise specific to each pixel and AD (Analog Digital) conversion can be adopted. The horizontal drive circuit 5 is, for example, composed of a shift register, and sequentially outputs horizontal scanning pulses to the column signal processing circuits 4, selects the column signal processing circuits 4 in order, and causes the selected column signal processing circuit 4 to output pixel signals that have been subjected to signal processing to the horizontal signal line 11.

[0014] The output circuit 6 performs signal processing on the pixel signals sequentially output from each of the column signal processing circuits 4 through the horizontal signal line 11, and outputs the processed signals. As the signal processing, various types of digital signal processing such as buffering, black level adjustment, column variation correction, etc. As the black level adjustment, for example, a process of correcting the black level of the pixel signal to "0" by subtracting a reference signal of an optical black level obtained from the pixel 8 (OPB pixel) in the light-shielded pixel region 13 from the pixel signal obtained from the pixel 8 (effective pixel) in the effective pixel region 12 can be adopted. The control circuit 7 generates clock signals and control signals that serve as a reference for the operation of the vertical drive circuit 3, the column signal processing circuit 4, the horizontal drive circuit 5, etc., based on a vertical synchronization signal, a horizontal synchronization signal, and a master clock signal (not shown). Then, the control circuit 7 outputs the generated clock signals and control signals to the vertical drive circuit 3, the column signal processing circuit 4, the horizontal drive circuit 5, etc.

[0015] [1-2 Main components] Next, the detailed structure of the solid-state imaging device 1 will be described. FIG. 2 is a diagram showing a planar configuration of one of the four corners of the pixel region 2. In FIG. 2, the structure above the light-shielding metals 18, 19 is omitted so that the light-shielding metals 18, 19 can be clearly seen. FIG. 3 is a diagram showing a cross-sectional configuration of the solid-state imaging device 1 when cut along line AA in FIG. 2. Note that FIG. 3 illustrates a case in which pupil correction is performed to shift the position of the light-shielding metal 18 toward the center of the pixel region 2 (the lower side in FIG. 3), and the photoelectric conversion unit PD is located below the light-shielding metal 18. FIG. 4 is a diagram showing a cross-sectional configuration of the solid-state imaging device 1 when cut along line BB in FIG. 2. As shown in FIG. 2, the pixel region 2 has an effective pixel region 12 located in the center of the pixel region 2 and a light-shielded pixel region 13 surrounding the effective pixel region 12. The effective pixel region 12 is a region where an object is imaged. As shown in FIG. 3, in the effective pixel region 12, the solid-state imaging device 1 has a semiconductor substrate 14, and an insulator 15, a first conductor 16, an insulating film 17, and a light-shielding metal 18 are laminated in this order on a light-receiving surface (hereinafter also referred to as a "rear surface S1" or in a broader sense) of the semiconductor substrate 14. Although nothing is shown on the light-receiving surface (hereinafter also referred to as a "rear surface S2") side of the light-shielding metal 18a in FIG. 3, a color filter, an on-chip lens, or the like may be formed thereon. In addition, a wiring layer 20 is disposed on a surface (hereinafter also referred to as a "front surface S3" or in a broader sense also referred to as a "second surface") of the semiconductor substrate 14 opposite to the rear surface S1. In addition, the light-shielding pixel region 13 is a region surrounding the periphery of the effective pixel region 12. In the light-shielded pixel region 13, the solid-state imaging device 1 has a semiconductor substrate 14 shared with the effective pixel region 12, and a light-shielding metal 19 is disposed on a back surface S1 of the semiconductor substrate 14. In addition, a wiring layer 20 is disposed on a front surface S3 of the semiconductor substrate 14.

[0016] The semiconductor substrate 14 is a substrate made of, for example, silicon (Si). The semiconductor substrate 14 is shared by the effective pixel region 12 and the light-shielded pixel region 13, and a photoelectric conversion unit PD is formed in each region corresponding to each pixel 8. That is, a plurality of photoelectric conversion units PD are formed in a two-dimensional array on the semiconductor substrate 14. The photoelectric conversion unit PD forms a photodiode by a pn junction of a p-type semiconductor region and an n-type semiconductor region, and photoelectrically converts incident light to generate electric charges. The generated electric charges are stored in an electrostatic capacitance generated by the pn junction. In addition, in the semiconductor substrate 14, an inter-pixel isolation structure 21 is formed in a region between the photoelectric conversion units PD. That is, the inter-pixel isolation structure 21 is formed in a lattice shape so as to surround each photoelectric conversion unit PD. In addition, the inter-pixel isolation structure 21 has a first inter-pixel isolation structure 22 which is a part in the effective pixel region 12, and a second inter-pixel isolation structure 23 which is a part in the light-shielding pixel region 13. The first inter-pixel isolation structure 22 is formed from the back surface S1 of the semiconductor substrate 14 to a partway between the back surface S1 and the front surface S3. In addition, in the first inter-pixel isolation structure 22, a first conductor 16 is arranged from the back surface S1 to a partway between the back surface S1 and the front surface S3. Specifically, the first inter-pixel isolation structure 22 has a trench portion 24, and an insulator 15 and a first conductor 16 arranged in the trench portion 24. The trench portion 24 is formed from the back surface S1 of the semiconductor substrate 14 to partway between the back surface S1 and the front surface S3, and its sidewall surface and bottom surface form the outline of the first inter-pixel isolation structure 22. The insulator 15 continuously covers the sidewall surface of the trench portion 24 and the back surface S1 of the semiconductor substrate 14 in the effective pixel region 12. The formation range of the insulator 15 on the back surface S1 side of the semiconductor substrate 14 is up to the boundary between the effective pixel region 12 and the light-shielding pixel region 13 so that the insulator 15 does not cover the back surface S1 of the light-shielding pixel region 13. As the material (insulating material) of the insulator 15, for example, silicon oxide (SiO) can be used.

[0017] The first conductor 16 is embedded in the space in the trench portion 24, that is, in the space between the sidewall surfaces covered with the insulator 15. As a result, each part of the first conductor 16 in the trench portion 24 is electrically integrated. The first conductor 16 is disposed from the back surface S1 of the semiconductor substrate 14 to the bottom surface of the trench portion 24. The first conductor 16 also covers the space in the trench portion 24, as well as the region (lattice region) along the photoelectric conversion units PD on the light receiving surface (hereinafter also referred to as the "back surface S6") of the insulator 15 located on the back surface S1 of the semiconductor substrate 14. That is, the first conductor 16 is disposed continuously in the first inter-pixel separation structure 22 and in the region along the photoelectric conversion units PD on the back surface S1 of the semiconductor substrate 14 in the effective pixel region 12. The formation range of the first conductor 16 on the back surface S6 side of the insulator 15 is up to the boundary between the effective pixel region 12 and the light-shielded pixel region 13 so as not to reach the light-shielded pixel region 13. A conductive material can be used as the material of the first conductor 16. For example, ITO (Indium Tin Oxide) can be used. In addition, between the end of the first inter-pixel isolation structure 22 on the surface S3 side and the surface S3 of the semiconductor substrate 14, STI 50 is formed in a lattice shape along the first inter-pixel isolation structure 22.

[0018] The second pixel isolation structure 23 is formed so as to penetrate the semiconductor substrate 14 from the back surface S1 to the front surface S3 of the semiconductor substrate 14. A conductor (hereinafter also referred to as a "second conductor 25") is disposed in the second pixel isolation structure from the back surface S1 to the front surface S3. Specifically, the second pixel isolation structure 23 has a trench portion 26, and an insulator 27 and the second conductor 25 disposed in the trench portion 26. The trench portion 26 penetrates the semiconductor substrate 14 from the back surface S1 to the front surface S3 of the semiconductor substrate 14, and the sidewall surface forms the outer shape of the second pixel isolation structure 23. The insulator 27 continuously covers the sidewall surface of the trench portion 26. For example, silicon oxide (SiO) can be used as the material of the insulator 27. The second conductor 25 is embedded in the space in the trench portion 26, that is, the space between the sidewall surfaces covered with the insulator 27. As a result, each part of the second conductor 25 in the trench portion 26 is electrically integrated. The space between the sidewall surfaces covered with the insulator 27 (that is, the space in the second inter-pixel isolation structure 23) and the space between the insulators 15 in the first inter-pixel isolation structure 22 are connected to each other, and the second conductor 25 and the first conductor 16 are electrically connected by contacting each other at their ends. The second conductor 25 is disposed so as to penetrate the semiconductor substrate 14 from the back surface S1 to the front surface S3 of the semiconductor substrate 14. By penetrating the semiconductor substrate 14, the second conductor 25 is exposed on each of the front surface S3 and the back surface S1 of the semiconductor substrate 14. A conductive material can be used as the material of the second conductor 25. For example, doped polysilicon doped with boron (B) or the like can be used. That is, in the first embodiment, the first conductor 16 and the second conductor 25 are formed using different conductive materials. More specifically, the first conductor 16 is formed using a conductive material having a lower light absorptance than the second conductor 25. The relationship between the light absorptance of ITO and the light absorptance of doped polysilicon is: light absorptance of ITO<light absorptance of doped polysilicon.

[0019] Further, the second conductor 25 has a surface S3 side electrically connected to a negative bias voltage supply source, and a negative bias voltage is applied from the surface S3 side. By applying a negative bias voltage, the peripheral portion of the second inter-pixel separation structure 23 can be made to have a high hole concentration in the light-shielded pixel region 13, and the generation of dark current can be suppressed. FIG. 3 illustrates an example in which a contact 28 formed on a portion of the second conductor 25 on the surface S3 side is connected to the second conductor 25, and the second conductor 25 is connected to the negative bias voltage supply source via the contact 28. The insulating film 17 is formed so as to continuously cover the light receiving surface of the first conductor 16 (hereinafter also referred to as "rear surface S4") and the portion of the rear surface S6 of the insulator 15 where the first conductor 16 is not present.

[0020] The light-shielding metal 18 is disposed on the light-receiving surface (hereinafter also referred to as "rear surface S5") of the insulating film 17 in the effective pixel region 12, and is formed so as to cover the region along the rear surface S5 of the insulating film 17 between the photoelectric conversion units PD in the effective pixel region 12. The light-shielding metal 19 is disposed on the rear surface S1 of the semiconductor substrate 14 in the light-shielding pixel region 13, and is formed so as to cover the entire rear surface S1 of the semiconductor substrate 14 in the light-shielding pixel region 13. The opposing surface (hereinafter also referred to as "front surface S7") of the light-shielding metal 19 facing the rear surface S1 of the semiconductor substrate 14 is in contact with and electrically connected to the second conductor 25 (i.e., the end of the second conductor 25 on the rear surface S1 side) exposed on the rear surface S1 of the semiconductor substrate 14. The end of the light-shielding metal 19 on the effective pixel region 12 side is in contact with and electrically connected to the end of the first conductor 16 on the rear surface S1 on the light-shielding pixel region 13 side. As a result, the first conductor 16 and the second conductor 25 are electrically connected to each other via the light-shielding metal 19. Therefore, a negative bias voltage applied to the second conductor 25 from the surface S3 side is applied to the first conductor 16 via the second conductor 25 and the light-shielding metal 19. That is, a transmission path for the negative bias voltage is formed using the light-shielding metal 19 used for shading the photoelectric conversion unit PD in the light-shielding pixel region 13. Therefore, in the effective pixel region 12, the periphery of the first inter-pixel separation structure 22 can be made into a high hole concentration state, and the generation of dark current can be suppressed. For example, tungsten (W), aluminum (Al), and copper (Cu) can be used as the material for the light-shielding metals 18 and 19. The light-shielding metals 18 and 19 are separated at the boundary between the effective pixel region 12 and the light-shielding pixel region 13 and are not electrically connected. The wiring layer 20 has an interlayer insulating film and wiring (not shown) stacked in multiple layers with the interlayer insulating film interposed therebetween, and drives a pixel transistor (not shown) of each pixel 8 via the multiple layers of wiring.

[0021] In the solid-state imaging device 1 having the above configuration, light is incident from the rear surface S1 side of the semiconductor substrate 14, the incident light is transmitted through an on-chip lens and a color filter (not shown), and the transmitted light is photoelectrically converted in the photoelectric conversion unit PD to generate electric charges. Then, the generated electric charges are output as pixel signals from vertical signal lines 10 (see FIG. 1) formed by wiring of the wiring layer 20. Furthermore, in the solid-state imaging device 1 according to the first embodiment, an end portion on the surface S3 side of the second conductor 25 in the second inter-pixel isolation structure 23 in the light-shielded pixel region 13 is electrically connected to a supply source of a negative bias voltage. As a result, a negative bias voltage is applied to the first conductor 16 in the first inter-pixel isolation structure 22 in the effective pixel region 12 via the second conductor 25 and the light-shielding metal 19, and the peripheral portion of the first inter-pixel isolation structure 22 is brought into a high hole concentration state, suppressing the generation of dark current.

[0022] Here, for example, consider a case where the same conductive material as the second conductor 25 in the second inter-pixel isolation structure 23 in the light-shielded pixel region 13 is embedded in the first conductor 16 in the first inter-pixel isolation structure 22 in the effective pixel region 12. That is, assume that doped polysilicon is also used as the material for the first conductor 16. In this case, since polysilicon has the property of absorbing light, incident light is absorbed in the first inter-pixel isolation structure 22 in the effective pixel region 12. As a result, the amount of light photoelectrically converted by the photoelectric conversion unit PD in the effective pixel region 12 decreases, and there is a possibility that the sensitivity will decrease. In contrast, in the solid-state imaging device 1 according to the first embodiment, the first conductor 16 in the first inter-pixel isolation structure 22 in the effective pixel region 12 and the second conductor 25 in the second inter-pixel isolation structure 23 in the light-shielding pixel region 13 are formed using different conductive materials. Therefore, by selecting a conductive material according to desired pixel characteristics as the conductive material of the first conductor 16 in the first inter-pixel isolation structure 22 in the effective pixel region 12, the characteristics of the pixel 8 can be improved. More specifically, in the first embodiment, the first conductor 16 is formed using a conductive material (ITO) having a lower light absorption rate than the second conductor 25. Therefore, in the effective pixel region 12, the absorption of incident light by the first inter-pixel isolation structure 22 can be suppressed, and a decrease in the sensitivity of the pixel 8 can be suppressed. In addition, the second conductor 25 is made of doped polysilicon. Here, doped polysilicon has better embedding properties than ITO. Therefore, during the manufacture of the solid-state imaging device 1, the process of embedding the second conductor 25 in the space within the trench portion 26 of the second inter-pixel isolation structure 23, that is, the narrow space penetrating the semiconductor substrate 14, can be performed relatively easily.

[0023] [1-3 Manufacturing method of solid-state imaging device] Next, a method for manufacturing the solid-state imaging device 1 according to the first embodiment will be described. First, as shown in Fig. 5, a semiconductor substrate 14 on which a second pixel isolation structure 23 and a wiring layer 20 are formed is prepared. Doped polysilicon is embedded as a second conductor 25 in the second pixel isolation structure 23. Then, a trench portion 24 of the first pixel isolation structure 22 is formed on the rear surface S1 of the prepared semiconductor substrate 14 using lithography and dry etching. Then, an insulator 27 is formed so as to continuously cover the sidewall surface of the formed trench portion 24 and the rear surface S1 of the semiconductor substrate 14. The insulator 27 can be formed by, for example, chemical vapor deposition (CVD) or thermal oxidation.

[0024] 6, the first conductor 16 is formed so as to continuously cover the space between the sidewall surfaces covered with the insulator 15 and the back surface S6 of the insulator 27. ITO, which has a lower light absorption rate than doped polysilicon, is used as the material of the first conductor 16. Then, as shown in FIG. 7, an insulating film 17 is formed on the back surface S4 of the first conductor 16, and then a resist mask 29 having an opening at a position where the light-shielding metal 19 (see FIG. 3) is to be formed is formed. Then, as shown in FIG. 8, etching is performed through the resist mask 29 to remove a part of the first conductor 16 and the insulator 15 to expose the back surface S1 of the semiconductor substrate 14. This exposes the second conductor 25 on the back surface S1. Then, the resist mask 29 is removed, and as shown in FIG. 9, a film of a constant thickness is formed on the entire back surface S1 side of the semiconductor substrate 14 using the material of the light-shielding metal 19 (for example, tungsten (W)). As a result, the surface S7 of the light-shielding metal 19 is electrically connected to the second conductor 25, and the end of the light-shielding metal 19 on the effective pixel region 12 side is electrically connected to the first conductor 16. Then, a contact 28 connected to a supply source of a negative bias voltage is connected to the first conductor 16 via the second conductor 25 and the light-shielding metal 19. Next, the material of the light-shielding metal 19 that has been formed is removed from the back surface S5 of the insulating film 17 in the effective pixel region 12 to form the light-shielding metal 19. Thereafter, the light-shielding metal 18 (see FIG. 3), a color filter, an on-chip lens, and the like are formed on the back surface S5 of the insulating film 17 in the effective pixel region 12. Through these steps, the solid-state imaging device 1 shown in FIG. 3 is manufactured.

[0025] 2. Second embodiment [2-1 Configuration of main parts] Next, a solid-state imaging device 1 according to a second embodiment of the present disclosure will be described. The overall configuration of the solid-state imaging device 1 according to the second embodiment is the same as that shown in FIG. 1, and therefore will not be illustrated. FIG. 10 is a diagram corresponding to FIG. 2 of the first embodiment, and is a diagram showing a planar configuration of one of the four corners of the pixel region 2 of the solid-state imaging device 1 according to the second embodiment. FIG. 11 is a diagram corresponding to FIG. 3 of the first embodiment, and is a diagram showing a cross-sectional configuration of the solid-state imaging device 1 when cut along the line CC in FIG. 10. FIG. 12 is a diagram corresponding to FIG. 4 of the first embodiment, and is a diagram showing a cross-sectional configuration of the solid-state imaging device 1 when cut along the line DD in FIG. 10. In FIGS. 10, 11, and 12, the same reference numerals are attached to parts corresponding to FIGS. 2, 3, and 4, and duplicated explanations will be omitted. The solid-state imaging device 1 according to the second embodiment is different from the solid-state imaging device 1 according to the first embodiment in the configurations and materials of the first conductor 16 and the second conductor 25, and the configuration of the light-shielding metal 18. Moreover, in the solid-state imaging device 1 according to the third embodiment, the insulating film 17 is omitted.

[0026] 11 and 12, the first conductors 16 are disposed in the space within the trench portion 24, i.e., in the space between the sidewall surfaces covered with the insulator 15, from the back surface S1 to the bottom surface of the trench portion 24. As a result, the first conductors 16 in each portion within the trench portion 24 are electrically integrated, and the back surface S1 side of the first conductors 16 is exposed to the back surface S1 of the semiconductor substrate 14. As the material (conductive material) of the first conductors 16, for example, doped polysilicon can be used. The second conductor 25 is embedded in the space in the trench portion 26, that is, in the space between the sidewall surfaces covered with the insulator 27. As a result, each portion of the second conductor 25 in the trench portion 26 is electrically integrated. The second conductor 25 is disposed so as to penetrate the semiconductor substrate 14 from the back surface S1 to the front surface S3 of the semiconductor substrate 14. By penetrating the semiconductor substrate 14, the second conductor 25 is exposed on each of the front surface S3 and the back surface S1 of the semiconductor substrate 14. The material (conductive material) of the second conductor 25 can be the same material as the light-shielding metal 19, and for example, tungsten (W) can be adopted. That is, in the second embodiment, the first conductor 16 is formed of a conductive material having a higher light absorption rate than the second conductor 25. The relationship between the light absorption rate of doped polysilicon and the light absorption rate of tungsten (W) is as follows: light absorption rate of doped polysilicon>light absorption rate of tungsten (W). Moreover, the second conductor 25 has its surface S3 electrically connected to a negative bias voltage source via the contact 28, and a negative bias voltage is applied from the surface S3. By applying the negative bias voltage, the peripheral portion of the second inter-pixel separation structure 23 in the light-shielded pixel region 13 can be brought into a high hole concentration state, and the generation of dark current can be suppressed.

[0027] The light-shielding metal 18 is disposed on the back surface S6 side of the insulator 15 in the effective pixel region 12, and is formed so as to cover the region along the photoelectric conversion unit PD on the back surface S6 of the insulator 15 in the effective pixel region 12. The surface of the light-shielding metal 18 facing the insulator 15 (hereinafter also referred to as the "front surface S8") has a convex portion 30 penetrating the insulator 15 at a portion facing the first conductor 16, and is in contact with and electrically connected to the first conductor 16 exposed on the back surface S1 of the semiconductor substrate 14 (i.e., the end of the first conductor 16 on the back surface S1 side). The light-shielding metal 19 is disposed on the back surface S1 side of the semiconductor substrate 14 in the light-shielding pixel region 13, and is formed so as to cover the entire back surface S1 of the semiconductor substrate 14 in the light-shielding pixel region 13. The front surface S7 of the light-shielding metal 19 is in contact with and electrically connected to the second conductor 25 exposed on the back surface S1 of the semiconductor substrate 14 (i.e., the end of the second conductor 25 on the back surface S1 side). As a result, the first conductor 16 and the second conductor 25 are electrically connected to each other via the light-shielding metals 18 and 19 . Therefore, the negative bias voltage applied to the second conductor 25 from the surface S3 side is applied to the first conductor 16 via the second conductor 25 and the light-shielding metals 18 and 19. That is, a transmission path of the negative bias voltage is formed using the light-shielding metal 18 and the light-shielding metal 19 used for shading the photoelectric conversion unit PD in the light-shielding pixel region 13. Therefore, in the effective pixel region 12, the peripheral portion of the first inter-pixel separation structure 22 can be made into a high hole concentration state, and the generation of dark current can be suppressed. For example, tungsten (W), aluminum (Al), and copper (Cu) can be used as the material of the light-shielding metals 18 and 19. FIG. 11 illustrates a case where the light-shielding metals 18 and 19 and the second conductor 25 are integrally formed using the same material. The light-shielding metal 18 and the light-shielding metal 19 are connected at the boundary between the effective pixel region 12 and the light-shielding pixel region 13 and integrally formed.

[0028] With the above configuration, in the solid-state imaging device 1 according to the second embodiment, the first conductor 16 in the first inter-pixel isolation structure 22 in the effective pixel region 12 and the second conductor 25 in the second inter-pixel isolation structure 23 in the light-shielding pixel region 13 are formed using different conductive materials. Therefore, by selecting a conductive material according to desired pixel characteristics as the conductive material of the first conductor 16 in the first inter-pixel isolation structure 22 in the effective pixel region 12, the characteristics of the pixel 8 can be improved. More specifically, in the second embodiment, the first conductor 16 is formed using a conductive material (doped polysilicon) having a higher light absorption rate than the second conductor 25. Therefore, in the effective pixel region 12, the absorption of incident light by the first inter-pixel isolation structure 22 can be improved, and optical color mixing can be more appropriately suppressed. Therefore, it is preferable in a configuration where color mixing is more of a problem than sensitivity, such as when a SPAD (Single Photon Avalanche Diode), in which avalanche multiplication occurs in response to incident photons and a current flows, is used as the photoelectric conversion unit PD.

[0029] 3. Third embodiment [3-1 Configuration of main parts] Next, a solid-state imaging device 1 according to a third embodiment of the present disclosure will be described. The overall configuration of the solid-state imaging device 1 of the third embodiment is the same as that of FIG. 1, and is therefore omitted from the illustration. FIG. 13 is a diagram corresponding to FIG. 3 of the first embodiment, and is a diagram showing a cross-sectional configuration of the solid-state imaging device 1 when cut along line AA in FIG. 2. FIG. 14 is a diagram corresponding to FIG. 4 of the first embodiment, and is a diagram showing a cross-sectional configuration of the solid-state imaging device 1 when cut along line BB in FIG. 2. In FIG. 13 and FIG. 14, parts corresponding to FIG. 3 and FIG. 4 are given the same reference numerals, and duplicated explanations will be omitted. The solid-state imaging device 1 according to the third embodiment differs from the solid-state imaging device 1 according to the first embodiment in the configuration of the insulator 15 and the materials and configurations of the first conductor 16 and the second conductor 25.

[0030] The insulator 15 continuously covers the sidewall surfaces of the trench portions 24 in the effective pixel region 12 and the entire back surface S1 of the semiconductor substrate 14 (both the effective pixel region 12 and the light-shielded pixel region 13). As shown in Figs. 13 and 14, the first conductor 16 is disposed in the space in the trench portion 24, that is, in the space between the sidewall surfaces covered with the insulator 15, from the back surface S1 to the bottom surface of the trench portion 24. This electrically integrates each portion of the first conductor 16 in the trench portion 24. In addition to the space in the trench portion 24, the first conductor 16 continuously covers a region (lattice region) along the photoelectric conversion units PD on the back surface S6 of the insulator 15 in the effective pixel region 12, and the entire back surface S6 of the insulator 15 in the light-shielded pixel region 13. That is, the first conductor 16 is continuously disposed in the first inter-pixel separation structure 22, a region along the photoelectric conversion units PD on the back surface S1 of the semiconductor substrate 14 in the effective pixel region 12, and the entire back surface S1 of the semiconductor substrate 14 in the light-shielded pixel region 13. In the light-shielded pixel region 13, the surface of the first conductor 16 facing the insulator 15 (hereinafter also referred to as "surface S9") has a protrusion 31 penetrating the insulator 15 at a portion facing the second conductor 25, and is in contact with the rear surface S1 of the semiconductor substrate 14. As the material (conductive material) of the first conductor 16, for example, ITO can be used.

[0031] The second conductor 25 is embedded in the space in the trench portion 26, that is, in the space between the sidewall surfaces covered with the insulator 27. As a result, each portion of the second conductor 25 in the trench portion 26 is electrically integrated. The second conductor 25 is disposed so as to penetrate the semiconductor substrate 14 from the back surface S1 to the front surface S3 of the semiconductor substrate 14. By penetrating the semiconductor substrate 14, the second conductor 25 is exposed on each of the front surface S3 and the back surface S1 of the semiconductor substrate 14. The end of the second conductor 25 exposed from the front surface S3 side is electrically connected to a negative bias voltage supply source via the contact 28, and a negative bias voltage is applied from the front surface S3 side. By applying the negative bias voltage, the peripheral portion of the second inter-pixel separation structure 23 can be brought into a high hole concentration state in the light-shielded pixel region 13, and the generation of dark current can be suppressed.

[0032] Moreover, the end of the second conductor 25 exposed from the back surface S1 side is in contact with and electrically connected to the first conductor 16 located on the back surface S1 side of the semiconductor substrate 14 in the light-shielding pixel region 13. As a result, the first conductor 16 and the second conductor 25 are electrically connected to each other without the light-shielding metals 18 and 19. Therefore, a negative bias voltage applied to the second conductor 25 from the front surface S3 side is applied to the first conductor 16 in the first pixel isolation structure 22 via the second conductor 25 and the first conductor 16 located on the back surface S1 side. That is, a transmission path of the negative bias voltage to the first conductor 16 in the first pixel isolation structure 22 is formed using the first conductor 16 located on the back surface S1 side. Therefore, in the effective pixel region 12, the peripheral portion of the first pixel isolation structure 22 can be brought into a high hole concentration state, and the generation of dark current can be suppressed. Moreover, for example, tungsten (W) can be used as the material (conductive material) of the second conductor 25. That is, in the third embodiment, the first conductor 16 is formed of a conductive material having a lower light absorptance than the second conductor 25. The relationship between the light absorptance of ITO and the light absorptance of tungsten (W) is: light absorptance of ITO<light absorptance of tungsten.

[0033] With the above configuration, in the solid-state imaging device 1 according to the third embodiment, the first conductor 16 in the first inter-pixel isolation structure 22 in the effective pixel region 12 and the second conductor 25 in the second inter-pixel isolation structure 23 in the light-shielding pixel region 13 are formed using different conductive materials. Therefore, by selecting a conductive material according to desired pixel characteristics as the conductive material of the first conductor 16 in the first inter-pixel isolation structure 22 in the effective pixel region 12, the characteristics of the pixel 8 can be improved. More specifically, in the third embodiment, the first conductor 16 is formed using a conductive material (ITO) having a lower light absorption rate than the second conductor 25. Therefore, in the effective pixel region 12, the absorption of incident light by the first inter-pixel isolation structure 22 can be suppressed, and the sensitivity can be improved. Also, the first conductor 16 located on the back surface S1 side of the semiconductor substrate 14 in the light-shielded pixel region 13 is configured to be used as a transmission path for a negative bias voltage. Therefore, compared to the case where the light-shielding metal 19 is used as the transmission path, for example, it is not necessary to prepare a material for forming the transmission path separately from the material for the first conductor 16, and an increase in the number of steps associated with the formation of the transmission path can be suppressed.

[0034] [3-2 Modifications] (1) In the first, second and third embodiments, an example has been shown in which a transmission path for a negative bias voltage is formed on the rear surface S1 side of the semiconductor substrate 14, but other configurations may also be adopted. For example, a configuration may be used in which a location at the boundary between the trench portion 24 of the first inter-pixel isolation structure 22 and the trench portion 26 of the second inter-pixel isolation structure 23 where the first conductor 16 and the second conductor 25 in the trench portions 24, 26 are in direct contact with each other is used as the transmission path for a negative bias voltage. (2) In the first, second and third embodiments, an example is shown in which a negative bias voltage is applied from the front surface S3 side of the second conductor 25, but other configurations may be adopted. For example, a configuration in which a negative bias voltage is applied from the back surface S1 side of the second conductor 25 may be adopted.

[0035] (3) Furthermore, the present technology can be applied to photodetection devices in general, including distance measuring sensors that measure distance, also called ToF (Time of Flight) sensors, in addition to the solid-state imaging device 1 as the image sensor described above. A distance measuring sensor is a sensor that emits irradiation light toward an object, detects the reflected light that is reflected by the surface of the object, and calculates the distance to the object based on the flight time from when the irradiation light is emitted to when the reflected light is received. The structure of pixel 8 described above can be adopted as the light receiving pixel structure of this distance measuring sensor.

[0036] 4. Fourth embodiment The technology according to the present disclosure (the present technology) can be applied to various electronic devices. FIG. 15 is a diagram showing an example of a schematic configuration of an imaging device (such as a video camera or a digital still camera) as an electronic device to which the present technology is applied. 15, the imaging device 1000 includes a lens group 1001, a solid-state imaging device 1002 (solid-state imaging device 1 according to the first embodiment), a DSP (Digital Signal Processor) circuit 1003, a frame memory 1004, a monitor 1005, and a memory 1006. The DSP circuit 1003, the frame memory 1004, the monitor 1005, and the memory 1006 are connected to each other via a bus line 1007.

[0037] A lens group 1001 guides incident light (image light) from a subject to a solid-state imaging device 1002 , and forms an image on a light receiving surface (pixel region) of the solid-state imaging device 1002 . The solid-state imaging device 1002 is made up of the CMOS image sensor according to the first embodiment described above. The solid-state imaging device 1002 converts the amount of incident light focused on the light receiving surface by the lens group 1001 into an electrical signal on a pixel-by-pixel basis and supplies the signal to the DSP circuit 1003 as a pixel signal. The DSP circuit 1003 performs predetermined image processing on the pixel signals supplied from the solid-state imaging device 1002. Then, the DSP circuit 1003 supplies the image signals after the image processing to a frame memory 1004 on a frame-by-frame basis, and causes the image signals to be temporarily stored in the frame memory 1004. The monitor 1005 is formed of a panel-type display device such as a liquid crystal panel, an organic EL (Electro Luminescence) panel, etc. The monitor 1005 displays an image (moving image) of a subject based on pixel signals temporarily stored in a frame memory 1004 on a frame-by-frame basis. The memory 1006 is composed of a DVD, a flash memory, etc. The memory 1006 reads out and records the pixel signals temporarily stored in the frame memory 1004 on a frame-by-frame basis.

[0038] Note that the electronic device to which the solid-state imaging device 1 can be applied is not limited to the imaging device 1000, but can also be applied to other electronic devices. In addition, although the solid-state imaging device 1 according to the first embodiment is used as the solid-state imaging device 1002, other configurations can also be adopted. For example, the solid-state imaging device 1 according to the second or third embodiment, the solid-state imaging device 1 according to a modification, or another photodetector to which the present technology is applied may be used.

[0039] 5. Fifth embodiment The technology according to the present disclosure (the present technology) can be applied to a medical imaging system. The medical imaging system is a medical system that uses imaging technology, such as an endoscope system or a microscope system.

[0040] [Endoscope system] An example of an endoscope system will be described with reference to Figs. 16 and 17. Fig. 16 is a diagram showing an example of a schematic configuration of an endoscope system 5000 to which the technology according to the present disclosure can be applied. Fig. 17 is a diagram showing an example of the configuration of an endoscope 5001 and a CCU (Camera Control Unit) 5039. Fig. 16 shows a state in which an operator (e.g., a doctor) 5067, who is a participant in the operation, performs an operation on a patient 5071 on a patient bed 5069 using the endoscope system 5000. As shown in Fig. 16, the endoscope system 5000 includes an endoscope 5001, which is a medical imaging device, a CCU 5039, a light source device 5043, a recording device 5053, an output device 5055, and a support device 5027 that supports the endoscope 5001.

[0041] In endoscopic surgery, an insertion aid called a trocar 5025 is inserted into a patient 5071. Then, a scope 5003 and a surgical tool 5021 connected to an endoscope 5001 are inserted into the body of the patient 5071 via the trocar 5025. The surgical tool 5021 is, for example, an energy device such as an electric scalpel, forceps, etc.

[0042] A surgical image, which is a medical image showing the inside of a patient 5071 taken by an endoscope 5001, is displayed on a display device 5041. An operator 5067 performs a procedure on a surgical target using a surgical tool 5021 while viewing the surgical image displayed on the display device 5041. Note that the medical image is not limited to a surgical image, and may be a diagnostic image taken during a diagnosis.

[0043] [Endoscopy] The endoscope 5001 is an imaging unit that images the inside of the body of the patient 5071, and is, for example, a camera 5005 including a light collecting optical system 50051 that collects incident light, a zoom optical system 50052 that changes the focal length of the imaging unit to enable optical zoom, a focus optical system 50053 that changes the focal length of the imaging unit to enable focus adjustment, and a light receiving element 50054, as shown in FIG. 17. The endoscope 5001 generates a pixel signal by collecting light on the light receiving element 50054 via the connected scope 5003, and outputs the pixel signal to the CCU 5039 through a transmission system. The scope 5003 has an objective lens at its tip, and is an insertion part that guides light from the connected light source device 5043 into the body of the patient 5071. The scope 5003 is, for example, a rigid scope in the case of a rigid endoscope, or a flexible scope in the case of a flexible endoscope. The scope 5003 may be a direct endoscope or an oblique endoscope. The pixel signal may be a signal based on a signal output from a pixel, for example, a RAW signal or an image signal. A memory may be mounted on the transmission system connecting the endoscope 5001 and the CCU 5039, and parameters related to the endoscope 5001 and the CCU 5039 may be stored in the memory. The memory may be disposed on, for example, a connection part or a cable of the transmission system. For example, the parameters at the time of shipment of the endoscope 5001 and the parameters changed when the power is applied may be stored in the memory of the transmission system, and the operation of the endoscope may be changed based on the parameters read from the memory. The endoscope and the transmission system may be referred to as an endoscope as a set. The light receiving element 50054 is a sensor that converts received light into a pixel signal, and is, for example, a CMOS (Complementary Metal Oxide Semiconductor) type imaging element. The light receiving element 50054 is preferably an imaging element having a Bayer array and capable of color photography. Also, the light receiving element 50054 is preferably an imaging element having a number of pixels corresponding to a resolution of, for example, 4K (3840 horizontal pixels x 2160 vertical pixels), 8K (7680 horizontal pixels x 4320 vertical pixels), or square 4K (3840 or more horizontal pixels x 3840 or more vertical pixels). The light receiving element 50054 may be a single sensor chip or multiple sensor chips.For example, a prism may be provided to separate the incident light into predetermined wavelength bands, and each wavelength band may be imaged by a different light receiving element. A plurality of light receiving elements may be provided for stereoscopic vision. The light receiving element 50054 may be a sensor including an arithmetic processing circuit for image processing in a chip structure, or may be a ToF (Time of Flight) sensor. The transmission system may be, for example, an optical fiber cable or wireless transmission. For wireless transmission, it is sufficient if the pixel signal generated by the endoscope 5001 can be transmitted. For example, the endoscope 5001 and the CCU 5039 may be wirelessly connected, or the endoscope 5001 and the CCU 5039 may be connected via a base station in the operating room. At this time, the endoscope 5001 may transmit not only the pixel signal but also information related to the pixel signal (for example, the processing priority of the pixel signal, a synchronization signal, etc.) at the same time. The endoscope may be configured such that the scope and the camera are integrated, or a light receiving element is provided at the tip of the scope.

[0044] [CCU (Camera Control Unit)] The CCU 5039 is a control device that comprehensively controls the connected endoscope 5001 and light source device 5043, and is, for example, an information processing device having an FPGA 50391, a CPU 50392, a RAM 50393, a ROM 50394, a GPU 50395, and an I / F 50396, as shown in FIG. 17. The CCU 5039 may also comprehensively control the connected display device 5041, recording device 5053, and output device 5055. For example, the CCU 5039 controls the irradiation timing and irradiation intensity of the light source device 5043, and the type of irradiation light source. The CCU 5039 also performs image processing such as development processing (e.g., demosaic processing) and correction processing on pixel signals output from the endoscope 5001, and outputs the processed pixel signals (e.g., images) to an external device such as the display device 5041. The CCU 5039 also transmits control signals to the endoscope 5001 to control the driving of the endoscope 5001. The control signal is, for example, information on imaging conditions such as the magnification and focal length of the imaging unit. The CCU 5039 may have an image down-conversion function and may be configured to simultaneously output a high-resolution (e.g., 4K) image to the display device 5041 and a low-resolution (e.g., HD) image to the recording device 5053.

[0045] The CCU 5039 may also be connected to an external device (e.g., a recording device, a display device, an output device, a support device) via an IP converter that converts a signal into a predetermined communication protocol (e.g., IP (Internet Protocol)). The connection between the IP converter and the external device may be configured as a wired network, or a part or all of the network may be constructed as a wireless network. For example, the IP converter on the CCU 5039 side may have a wireless communication function, and may transmit the received video to an IP switcher or an output-side IP converter via a wireless communication network such as a fifth-generation mobile communication system (5G) or a sixth-generation mobile communication system (6G).

[0046] [Light source device] The light source device 5043 is a device capable of emitting light in a predetermined wavelength band, and includes, for example, a plurality of light sources and a light source optical system that guides the light from the plurality of light sources. The light sources are, for example, a xenon lamp, an LED light source, or an LD light source. The light source device 5043 has, for example, LED light sources corresponding to each of the three primary colors R, G, and B, and emits white light by controlling the output intensity and output timing of each light source. The light source device 5043 may also have a light source capable of emitting special light used in special light observation, in addition to a light source that emits normal light used in normal light observation. The special light is light in a predetermined wavelength band different from normal light, which is light for normal light observation, and is, for example, near-infrared light (light with a wavelength of 760 nm or more), infrared light, blue light, or ultraviolet light. The normal light is, for example, white light or green light. In narrowband light observation, which is a type of special light observation, blue light and green light are alternately irradiated to utilize the wavelength dependency of light absorption in body tissue, and a predetermined tissue such as blood vessels on the surface of the mucous membrane can be photographed with high contrast. In addition, in a fluorescent observation, which is a type of special light observation, excitation light that excites a drug injected into a body tissue is irradiated, and fluorescence emitted by the body tissue or the drug as a marker is received to obtain a fluorescent image, thereby making it easier for the surgeon to visually recognize body tissues that are difficult for the surgeon to visually recognize under normal light. For example, in a fluorescent observation using infrared light, infrared light having an excitation wavelength band is irradiated to a drug such as indocyanine green (ICG) injected into the body tissue, and the fluorescence of the drug is received, making it easier to visually recognize the structure of the body tissue and the affected area. In addition, in a fluorescent observation, a drug (e.g., 5-ALA) that is excited by special light in a blue wavelength band and emits fluorescence in a red wavelength band may be used. The type of irradiation light is set for the light source device 5043 under the control of the CCU 5039. The CCU 5039 may have a mode in which normal light observation and special light observation are alternately performed by controlling the light source device 5043 and the endoscope 5001. At this time, it is preferable that information based on a pixel signal obtained by special light observation is superimposed on a pixel signal obtained by normal light observation. The special light observation may be infrared observation in which infrared light is irradiated to view the inside of an organ from its surface, or multispectral observation using hyperspectral spectroscopy. Photodynamic therapy may also be combined.

[0047] [Recording device] The recording device 5053 is a device that records pixel signals (e.g., images) acquired from the CCU 5039, and is, for example, a recorder. The recording device 5053 records images acquired from the CCU 5039 in a HDD, an SDD, or an optical disk. The recording device 5053 may be connected to a network within the hospital and may be accessible from devices outside the operating room. The recording device 5053 may also have an image down-conversion or up-conversion function.

[0048] [Display device] The display device 5041 is a device capable of displaying an image, such as a display monitor. The display device 5041 displays a display image based on a pixel signal acquired from the CCU 5039. The display device 5041 may also function as an input device that enables gaze recognition, voice recognition, and instruction input by gestures by including a camera and a microphone.

[0049] [Output device] The output device 5055 is a device, such as a printer, that outputs information acquired from the CCU 5039. The output device 5055 prints, for example, a print image based on a pixel signal acquired from the CCU 5039 onto paper.

[0050] [Support device] The support device 5027 is a multi-joint arm including a base section 5029 having an arm control device 5045, an arm section 5031 extending from the base section 5029, and a holding section 5032 attached to the tip of the arm section 5031. The arm control device 5045 is configured by a processor such as a CPU, and controls the driving of the arm section 5031 by operating according to a predetermined program. The support device 5027 controls the position and posture of the endoscope 5001 held by the holding section 5032, for example, by controlling parameters such as the length of each link 5035 constituting the arm section 5031 and the rotation angle and torque of each joint 5033 by the arm control device 5045. This allows the endoscope 5001 to be changed to a desired position or posture, the scope 5003 to be inserted into the patient 5071, and the observation area inside the body to be changed. The support device 5027 functions as an endoscope support arm that supports the endoscope 5001 during surgery. Thereby, the support device 5027 can take the place of a scopist who is an assistant holding the endoscope 5001. The support device 5027 may be a device that supports a microscope device 5301 described later, and may be called a medical support arm. The control of the support device 5027 may be an autonomous control method by the arm control device 5045, or a control method in which the arm control device 5045 controls based on a user's input. For example, the control method may be a master-slave method in which the support device 5027 as a slave device (replica device) that is a patient cart is controlled based on the movement of a master device (primary device) that is an operator console at the user's hand. The control of the support device 5027 may be remotely controlled from outside the operating room.

[0051] The above describes an example of the endoscope system 5000 to which the technology according to the present disclosure can be applied. For example, the technology according to the present disclosure may be applied to a microscope system.

[0052] [Microscope system] 18 is a diagram showing an example of a schematic configuration of a microsurgery system to which the technology according to the present disclosure can be applied. In the following description, the same components as those in the endoscope system 5000 are denoted by the same reference numerals, and duplicated descriptions thereof will be omitted.

[0053] 18 shows a schematic diagram of an operator 5067 performing surgery on a patient 5071 on a patient bed 5069 using a microsurgery system 5300. For simplicity, the cart 5037 of the microsurgery system 5300 is not shown in FIG. 18, and a microscope device 5301 replacing the endoscope 5001 is shown in a simplified form. However, the microscope device 5301 in this description may refer to the microscope unit 5303 provided at the tip of the link 5035, or may refer to the entire configuration including the microscope unit 5303 and the support device 5027.

[0054] 18, during surgery, a microsurgery system 5300 is used to display an image of the surgical site captured by a microscope device 5301 on a display device 5041 installed in an operating room in an enlarged scale. The display device 5041 is installed in a position facing an operator 5067, who performs various treatments on the surgical site, such as resection of the affected area, while observing the state of the surgical site using the image displayed on the display device 5041. The microsurgery system is used, for example, in ophthalmic surgery or brain surgery.

[0055] Above, examples of the endoscopic system 5000 and the microsurgery system 5300 to which the technology according to the present disclosure can be applied have been described. Note that the systems to which the technology according to the present disclosure can be applied are not limited to these examples. For example, the support device 5027 may support other observation devices or other surgical tools at its tip instead of the endoscope 5001 or the microscope unit 5303. As the other observation devices, for example, forceps, a pneumoperitoneum tube for pneumoperitoneum, or an energy treatment tool for incising tissue or sealing blood vessels by cauterization may be applied. By supporting these observation devices and surgical tools with the support device, it is possible to fix the positions more stably and reduce the burden on the medical staff compared to when the medical staff supports them manually. The technology according to the present disclosure may be applied to a support device that supports a configuration other than the microscope unit.

[0056] The technology according to the present disclosure can be suitably applied to the light receiving element among the above-described configurations. By applying the technology according to the present disclosure to the light receiving element, a clearer image of the surgical site can be obtained, so that the surgery can be performed safely and reliably.

[0057] The present technology can also be configured as follows. (1) A semiconductor substrate; A plurality of photoelectric conversion units formed in a two-dimensional array on the semiconductor substrate; an inter-pixel isolation structure formed in a region between the photoelectric conversion units of the semiconductor substrate, the inter-pixel isolation structure has a first inter-pixel isolation structure which is a portion within an effective pixel area, and a second inter-pixel isolation structure which is a portion within a light-shielding pixel area surrounding the periphery of the effective pixel area, a first conductor is disposed in the first inter-pixel isolation structure; a second conductor electrically connected to the first conductor and to which a negative bias voltage is applied is disposed in the second inter-pixel separation structure; The first conductor and the second conductor are formed using different conductive materials. Light detection device. (2) a light-shielding metal disposed on the first surface side of the semiconductor substrate, the first surface being a light-receiving surface of the semiconductor substrate, the light-shielding metal covering the first surface of the semiconductor substrate in the light-shielding pixel region; the first conductor and the second conductor are electrically connected to each other via the light-shielding metal, The second conductor is applied with the negative bias voltage from the second surface side. The light detection device according to (1) above. (3) The first conductor is made of a conductive material having a lower light absorption rate than the second conductor. The optical detection device according to (2) above. (4) the material of the first conductor is ITO; The material of the second conductor is doped polysilicon. The optical detection device according to (3) above. (5) the first inter-pixel separation structure and the first conductor are formed from the first surface to a midpoint between the first surface and a second surface that is an opposite surface to the first surface, The second inter-pixel isolation structure and the second conductor are formed to penetrate the semiconductor substrate from the first surface to the second surface. The optical detection device according to (3) or (4). (6) the first conductor is continuously disposed in the first inter-pixel isolation structure and in a region along between the photoelectric conversion units on the first surface of the semiconductor substrate in the effective pixel region, and an end portion of the first conductor located on the first surface on the light-shielding pixel region side is in contact with and electrically connected to an end portion of the light-shielding metal on the effective pixel region side; The second conductor has an end portion on the first surface side in contact with and electrically connected to an opposing surface of the light-shielding metal that faces the first surface. The optical detection device according to (5) above. (7) The first conductor is formed of a conductive material having a higher light absorption rate than the second conductor. The optical detection device according to (2) above. (8) the first conductor material is doped polysilicon; The material of the second conductor is tungsten. The light detection device according to (7) above. (9) the first inter-pixel separation structure and the first conductor are formed from the first surface to a midpoint between the first surface and a second surface that is an opposite surface to the first surface, The second inter-pixel isolation structure and the second conductor are formed to penetrate the semiconductor substrate from the first surface to the second surface. The optical detection device according to (7) or (8). (10) the light-shielding metal covers the entire first surface of the semiconductor substrate in the light-shielding pixel region and a region of the first surface of the semiconductor substrate along a gap between the photoelectric conversion units in the effective pixel region, The first and second conductors have ends on the first surface side in contact with and electrically connected to an opposing surface of the light-shielding metal that faces the first surface. The light detection device according to (9) above. (11) the first inter-pixel isolation structure and the first conductor are formed from a first surface, which is a light receiving surface of the semiconductor substrate, to a midway point between the first surface and a second surface, which is a surface opposite to the first surface; the second inter-pixel isolation structure and the second conductor are formed to penetrate the semiconductor substrate from the first surface to the second surface, the first conductor is continuously disposed in the first inter-pixel isolation structure, in a region along between the photoelectric conversion units on a first surface that is a light receiving surface of the semiconductor substrate in the effective pixel region, and over the entire first surface of the semiconductor substrate in the light-shielded pixel region; an end portion of the second conductor on the first surface side is in contact with and electrically connected to an opposing surface of the first conductor that faces the first surface; The second conductor is applied with the negative bias voltage from the second surface side. The light detection device according to (1) above. (12) The first conductor is made of a conductive material having a lower light absorption rate than the second conductor. The optical detection device according to (11) above. (13) the material of the first conductor is ITO; The material of the second conductor is tungsten. The light detection device according to (12) above. (14) a photodetector including a semiconductor substrate, a plurality of photoelectric conversion units formed in a two-dimensional array on the semiconductor substrate, and an inter-pixel isolation structure formed in a region between the photoelectric conversion units of the semiconductor substrate, the inter-pixel isolation structure including a first inter-pixel isolation structure which is a portion within an effective pixel region, and a second inter-pixel isolation structure which is a portion within a light-shielded pixel region surrounding the periphery of the effective pixel region, a first conductor is disposed within the first inter-pixel isolation structure, and a second conductor is disposed within the second inter-pixel isolation structure, the second conductor being electrically connected to the first conductor and receiving a negative bias voltage, the first conductor and the second conductor being formed using mutually different conductive materials; electronic equipment. [Explanation of symbols]

[0058] 1...solid-state imaging device, 2...pixel region, 3...vertical drive circuit, 4...column signal processing circuit, 5...horizontal drive circuit, 6...output circuit, 7...control circuit, 8...pixel, 9...pixel drive wiring, 10...vertical signal line, 11...horizontal signal line, 12...effective pixel region, 13...light-shielding pixel region, 14...semiconductor substrate, 15...insulator, 16...first conductor, 17...insulating film, 18, 19...light-shielding metal, 20...wiring layer, 21...inter-pixel isolation structure, 22...first inter-pixel isolation structure, 23...second inter-pixel isolation structure, 24...trench portion, 25...second conductor, 26...trench portion, 27...insulator, 28...contact, 29...resist mask, 30, 31...protruding portion

Claims

1. A semiconductor substrate; A plurality of photoelectric conversion units formed in a two-dimensional array on the semiconductor substrate; an inter-pixel isolation structure formed in a region between the photoelectric conversion units of the semiconductor substrate, the inter-pixel isolation structure has a first inter-pixel isolation structure which is a portion within an effective pixel area, and a second inter-pixel isolation structure which is a portion within a light-shielding pixel area surrounding a periphery of the effective pixel area, a first conductor is disposed in the first inter-pixel isolation structure; a second conductor electrically connected to the first conductor and to which a negative bias voltage is applied is disposed in the second pixel separation structure; The first conductor and the second conductor are formed using different conductive materials. Light detection device.

2. a light-shielding metal disposed on a first surface side, which is a light-receiving surface of the semiconductor substrate, and covering the first surface of the semiconductor substrate in the light-shielding pixel region; The first conductor and the second conductor are electrically connected to each other via the light-shielding metal.

2. The optical detection device according to claim 1.

3. The first conductor is formed of a conductive material having a lower light absorption rate than the second conductor.

3. The optical detection device according to claim 2.

4. the material of the first conductor is ITO; The material of the second conductor is doped polysilicon.

4. The optical detection device according to claim 3.

5. the first inter-pixel isolation structure and the first conductor are formed from the first surface to a midpoint between the first surface and a second surface that is an opposite surface to the first surface, The second inter-pixel isolation structure and the second conductor are formed to penetrate the semiconductor substrate from the first surface to the second surface.

4. The optical detection device according to claim 3.

6. the first conductor is continuously disposed in the first inter-pixel isolation structure and in a region along between the photoelectric conversion units on the first surface of the semiconductor substrate in the effective pixel region, and an end portion of the first conductor located on the first surface on the light-shielding pixel region side is in contact with and electrically connected to an end portion of the light-shielding metal on the effective pixel region side; an end portion of the second conductor on the first surface side is in contact with and electrically connected to an opposing surface of the light-shielding metal that faces the first surface; The negative bias voltage is applied to the second conductor from the second surface side.

6. The optical detection device according to claim 5.

7. The first conductor is formed of a conductive material having a higher light absorption rate than the second conductor.

3. The optical detection device according to claim 2.

8. the first conductor material is doped polysilicon; The material of the second conductor is tungsten.

8. The optical detection device according to claim 7.

9. the first inter-pixel isolation structure and the first conductor are formed from the first surface to a midpoint between the first surface and a second surface that is an opposite surface to the first surface, The second inter-pixel isolation structure and the second conductor are formed to penetrate the semiconductor substrate from the first surface to the second surface.

8. The optical detection device according to claim 7.

10. the light-shielding metal covers the entire first surface of the semiconductor substrate in the light-shielding pixel region and a region of the first surface of the semiconductor substrate along a gap between the photoelectric conversion units in the effective pixel region, the first conductor and the second conductor have ends on the first surface side in contact with and electrically connected to an opposing surface of the light-shielding metal that faces the first surface, The negative bias voltage is applied to the second conductor from the second surface side.

10. The optical detection device according to claim 9.

11. the first inter-pixel isolation structure and the first conductor are formed from a first surface, which is a light receiving surface of the semiconductor substrate, to a middle point between the first surface and a second surface, which is a surface opposite to the first surface; the second inter-pixel isolation structure and the second conductor are formed to penetrate the semiconductor substrate from the first surface to the second surface, the first conductor is continuously disposed in the first inter-pixel isolation structure, in a region along between the photoelectric conversion units on a first surface that is a light receiving surface of the semiconductor substrate in the effective pixel region, and over the entire first surface of the semiconductor substrate in the light-shielded pixel region; an end portion of the second conductor on the first surface side is in contact with and electrically connected to an opposing surface of the first conductor that faces the first surface; The negative bias voltage is applied to the second conductor from the second surface side.

2. The optical detection device according to claim 1.

12. The first conductor is formed of a conductive material having a lower light absorption rate than the second conductor. The optical detection device according to claim 11.

13. the material of the first conductor is ITO; The material of the second conductor is tungsten.

13. The optical detection device of claim 12.

14. a photodetector including a semiconductor substrate, a plurality of photoelectric conversion units formed in a two-dimensional array on the semiconductor substrate, and an inter-pixel isolation structure formed in a region between the photoelectric conversion units of the semiconductor substrate, the inter-pixel isolation structure including a first inter-pixel isolation structure which is a portion within an effective pixel region, and a second inter-pixel isolation structure which is a portion within a light-shielded pixel region surrounding the periphery of the effective pixel region, a first conductor is disposed within the first inter-pixel isolation structure, and a second conductor is disposed within the second inter-pixel isolation structure, the second conductor being electrically connected to the first conductor and having a negative bias voltage applied thereto, the first conductor and the second conductor being formed using mutually different conductive materials; electronic equipment.

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