Solid-state imaging device and electronic device

Abstract

Provided is a solid-state imaging device with which incident light that passes through an effective pixel region and infiltrates into an optical black pixel region can be weakened. The present invention is configured such that: from among a plurality of linear grooves that constitute trenches, a specific linear groove is formed with a different shape than that of a third linear groove formed between photoelectric conversion parts in the effective pixel region, the specific linear groove being either a first linear groove formed in a boundary between the effective pixel region and the optical black pixel region (OPB pixel region), or a plurality of second linear grooves formed in the OPB pixel region parallel to the boundary in a plan view; and a light-shielding material is embedded in the specific linear groove.

Description

[Technical field]

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

[0002] Conventionally, a solid-state imaging device has been proposed that has an effective pixel area and an optical black pixel area (hereinafter also referred to as an "OPB pixel area") that is adjacent to the effective pixel area and has a light receiving surface side shielded from light by a light shielding film (see, for example, Patent Document 1). The solid-state imaging device described in Patent Document 1 is configured to obtain a reference signal for an optical black level by pixels in the OPB pixel area. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-211413 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, near the boundary between the effective pixel area and the OPB pixel area, the incident light that enters the effective pixel area is inclined so as to proceed toward the OPB pixel area, so that it passes through the effective pixel area and enters the OPB pixel area. Therefore, the pixel used to acquire the reference signal (hereinafter also referred to as the "OPB pixel") had to be sufficiently far away from the boundary between the effective pixel area and the OPB pixel area. Therefore, it was necessary to arrange invalid pixels whose pixel signals were not used between the effective pixel area and the OPB pixel. There were about 10 to 20 rows of invalid pixels. As a result, the OPB pixel area expanded, the chip area expanded, and the manufacturing cost increased. Alternatively, it was necessary to reduce the effective pixel area by the amount of the expansion of the OPB pixel area. An object of the present disclosure is to provide a solid-state imaging device and electronic device capable of attenuating incident light that passes through an effective pixel area and enters an optical black pixel area. [Means for solving the problem]

[0005] The solid-state imaging device of the present disclosure comprises: (a) a pixel region formed on a substrate and having a plurality of photoelectric conversion units arranged in an array; and (b) a pixel separation portion including trench portions formed in a lattice pattern between the photoelectric conversion units; (c) the pixel region is partitioned into an effective pixel region having photoelectric conversion units for obtaining pixel signals corresponding to incident light, and an optical black pixel region adjacent to the effective pixel region, the light receiving surface side of which is covered with a light-shielding film, and having photoelectric conversion units for obtaining a reference signal for an optical black level; and (d) of the plurality of linear groove portions constituting the trench portion, a specific linear groove portion which is either a first linear groove portion formed at the boundary between the effective pixel region and the optical black pixel region or a plurality of second linear groove portions formed in the optical black pixel region and parallel to the boundary in a planar view has a different shape from a third linear groove portion formed between pixels in the effective pixel region, and has a light-shielding material embedded therein.

[0006] The electronic device of the present disclosure further comprises: (a) a pixel region formed on a substrate and having a plurality of photoelectric conversion units arranged in an array; and a pixel separation unit including a trench portion formed in a lattice shape between the photoelectric conversion units, the pixel region being partitioned into an effective pixel region having a photoelectric conversion unit for obtaining a pixel signal corresponding to incident light, and an optical black pixel region adjacent to the effective pixel region, the light receiving surface side of which is covered with a light shielding film, and having a photoelectric conversion unit for obtaining a reference signal for an optical black level; and The specific straight groove portion, which is either a first straight groove portion formed at the boundary with the optical black pixel region or a plurality of second straight groove portions formed within the optical black pixel region and parallel to the boundary in a planar view, has a shape different from that of a third straight groove portion formed between pixels in the effective pixel region, and has a light-shielding material embedded therein. The solid-state imaging device is provided with: (b) an optical lens that focuses image light from a subject on the imaging surface of the solid-state imaging device; and (c) a signal processing circuit that performs signal processing on a signal output from the solid-state imaging device. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an overall configuration of a solid-state imaging device according to a first embodiment. [Figure 2A] 2 is a diagram showing a cross-sectional configuration of a pixel region when cut along line AA in FIG. 1. FIG. [Figure 2B] 2B is a diagram showing a cross-sectional configuration of a pixel region when cut along line BB in FIG. 2A. FIG. [Diagram 3] FIG. 13 is a diagram showing a cross-sectional configuration of a pixel region according to a modified example. [Figure 4] FIG. 13 is a diagram showing a cross-sectional configuration of a pixel region according to a modified example. [Diagram 5] FIG. 11 is a diagram showing a cross-sectional configuration of a pixel region according to a second embodiment. [Figure 6A] 13A and 13B are diagrams illustrating the shape of a photoelectric conversion unit according to a modified example. [Figure 6B] 13A and 13B are diagrams illustrating the shape of a photoelectric conversion unit according to a modified example. [Figure 7] FIG. 1 is a diagram illustrating an example of a schematic configuration of an electronic device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An example of a solid-state imaging device 1 and an electronic device according to an embodiment of the present disclosure will be described below with reference to FIGS. 1 to 7. The embodiments of the present disclosure will be described in the following order. Note that the present disclosure is not limited to the following examples. Also, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0009] 1. First embodiment: solid-state imaging device 1-1 Overall configuration of solid-state imaging device 1-2 Main components 2. Second embodiment: Solid-state imaging device 2-1 Main components 2-2 Variations 3. Application examples to electronic devices

[0010] 1. First embodiment: solid-state imaging device [1-1 Overall configuration of solid-state imaging device] A solid-state imaging device 1 according to a first embodiment of the present disclosure will be described below. Fig. 1 is a schematic configuration diagram showing the entire solid-state imaging device 1 according to the first embodiment of the present disclosure. The solid-state imaging device 1 in Fig. 1 is a back-illuminated CMOS (Complementary Metal Oxide Semiconductor) image sensor. As shown in Fig. 7, the solid-state imaging device 1 (101) captures image light (incident light 106) from a subject via an optical lens 102, converts the amount of incident light 106 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 of the first embodiment includes a substrate 2, a pixel region 3, a vertical drive circuit 4, a column signal processing circuit 5, a horizontal drive circuit 6, an output circuit 7, and a control circuit 8.

[0011] The pixel region 3 has a plurality of pixels 9 arranged in a two-dimensional array on the substrate 2. The pixel 9 has a photoelectric conversion unit 17 shown in Fig. 2A and Fig. 2B and a plurality of pixel transistors (not shown). As the plurality of pixel transistors, for example, four transistors can be used: a transfer transistor, a reset transistor, a selection transistor, and an amplifier transistor. Alternatively, for example, three transistors excluding the selection transistor may be used.

[0012] The vertical drive circuit 4 is configured with, for example, a shift register, selects a desired pixel drive wiring 10, supplies a pulse for driving the pixels 9 to the selected pixel drive wiring 10, and drives each pixel 9 row by row. That is, the vertical drive circuit 4 selects and scans each pixel 9 in the pixel region 3 row by row in the vertical direction, and supplies a pixel signal based on a signal charge generated in the photoelectric conversion unit 17 of each pixel 9 according to the amount of received light to the column signal processing circuit 5 through the vertical signal line 11.

[0013] The column signal processing circuit 5 is arranged, for example, for each column of pixels 9, and performs signal processing such as noise removal for each pixel column on signals output from one row of pixels 9. For example, the column signal processing circuit 5 performs signal processing such as CDS (Correlated Double Sampling) and AD (Analog Digital) conversion for removing fixed pattern noise specific to each pixel. The horizontal drive circuit 6 is, for example, composed of a shift register, and sequentially outputs horizontal scanning pulses to the column signal processing circuits 5, selects each of the column signal processing circuits 5 in turn, and outputs pixel signals that have been subjected to signal processing from each of the column signal processing circuits 5 to the horizontal signal line 12.

[0014] The output circuit 7 performs signal processing on the pixel signals sequentially supplied from each of the column signal processing circuits 5 through the horizontal signal line 12, and outputs the processed signal. For example, the signal processing may include buffering, optical black level adjustment, column variation correction, various digital signal processing, etc. For example, the optical black level adjustment may be a process of correcting the black level of the pixel signal to "0" by subtracting a reference signal of the optical black level obtained from the pixels 9 in the optical black pixel area 20 from the pixel signal obtained from the pixels 9 in the effective pixel area 19. The control circuit 8 generates clock signals and control signals that serve as a reference for the operation of the vertical drive circuit 4, the column signal processing circuit 5, the horizontal drive circuit 6, etc., based on the vertical synchronization signal, the horizontal synchronization signal, and the master clock signal. Then, the control circuit 8 outputs the generated clock signals and control signals to the vertical drive circuit 4, the column signal processing circuit 5, the horizontal drive circuit 6, etc.

[0015] [1-2 Configuration of main parts] Next, a detailed structure of the solid-state imaging device 1 in Fig. 1 will be described. Fig. 2A is a diagram showing a cross-sectional configuration of a pixel region 3 of the solid-state imaging device 1. Fig. 2B is a diagram showing a planar configuration of the substrate 2 when cut along line BB in Fig. 2A. In Figs. 2A and 2B, a back-illuminated CMOS image sensor (CMOS solid-state imaging device) is used as the solid-state imaging device 1.

[0016] As shown in FIGS. 2A and 2B, the solid-state imaging device 1 of the first embodiment includes a light receiving layer 16 formed by laminating a substrate 2, an insulating film 13, a light shielding film 14, and a planarizing film 15 in this order. The substrate 2 is configured by a semiconductor substrate made of, for example, silicon (Si), and forms the pixel region 3 shown in Fig. 1. In the pixel region 3, as shown in Fig. 2A and Fig. 2B, a plurality of pixels 9 including a plurality of photoelectric conversion units 17 formed on the substrate 2, i.e., a plurality of photoelectric conversion units 17 embedded in the substrate 2, are arranged in a two-dimensional array. In the photoelectric conversion units 17, signal charges according to the amount of incident light 18 are generated, and the generated signal charges are accumulated.

[0017] 1, the pixel region 3 is divided into an effective pixel region 19 and an optical black pixel region 20 (hereinafter also referred to as "OPB pixel region 20"). The effective pixel region 19 is a region in which a photoelectric conversion unit 17 for obtaining a pixel signal corresponding to incident light 18 is formed. The OPB pixel region 20 is adjacent to the effective pixel region 19, has a light receiving surface side covered with a light shielding film 14, and is a region in which a photoelectric conversion unit 17 for obtaining a pixel signal of an optical black level (hereinafter also referred to as "reference signal") is formed. FIG. 1 illustrates a configuration in which the effective pixel region 19 is located in the center of the pixel region 3 and the OPB pixel region 20 is located on the periphery of the pixel region 3. When the OPB pixel region 20 is located on the periphery of the pixel region 3, the pixels 9 (OPB pixels 9) used to obtain a reference signal for the optical black level can be, among the pixels 9 in the OPB pixel region 20, a plurality of pixel rows 21a arranged parallel to the top edge of the effective pixel region 19 in a planar view at a position away from the top edge, a plurality of pixel rows 21b arranged parallel to the bottom edge of the effective pixel region 19 in a planar view at a position away from the bottom edge, a plurality of pixel rows 21c arranged parallel to the left edge of the effective pixel region 19 in a planar view at a position away from the left edge, and a plurality of pixel rows 21d arranged parallel to the right edge of the effective pixel region 19 in a planar view.

[0018] Moreover, each photoelectric conversion unit 17 is physically separated by a pixel separation unit 22. The pixel separation unit 22 is formed in a lattice shape so as to surround each photoelectric conversion unit 17. The pixel separation unit 22 has a trench unit 23 (groove unit) formed in the depth direction from the surface of the substrate 2 facing the insulating film 13 (hereinafter also referred to as the "rear surface S1"). That is, the trench unit 23 is formed between adjacent photoelectric conversion units 17 on the rear surface S1 side of the substrate 2. Similarly to the pixel separation unit 22, the trench unit 23 is formed in a lattice shape so as to surround each photoelectric conversion unit 17.

[0019] Among the multiple linear grooves 24 constituting the trench portion 23, the linear grooves 24 (hereinafter also referred to as "first linear grooves 24a") formed on the boundary between the effective pixel region 19 and the OPB pixel region 20 have a different shape from the linear grooves 24 formed between the photoelectric conversion sections 17 in the effective pixel region 19. Specifically, the first linear grooves 24a are deeper than the linear grooves 24 (hereinafter also referred to as "third linear grooves 24c") disposed between the pixels 9 in the effective pixel region 19. The sidewall surfaces and bottom surface of the first linear grooves 24a are covered with an insulating film 13 covering the rear surface S1 side of the substrate 2. The insulating film 13 has a uniform thickness so as not to fill the entire first linear grooves 24a in order to form a space in the first linear grooves 24a.

[0020] Also, a light-shielding material 25 is embedded in the space surrounded by the insulating film 13 in the first linear groove portion 24a. As the light-shielding material 25, metals such as aluminum (Al), tungsten (W), and copper (Cu) can be used. By using aluminum, tungsten, or copper, the light-shielding property can be improved. In this way, by making the depth of the first linear groove portion 24a deeper than the depth of the third linear groove portion 24c and embedding the light-shielding material 25 in the first linear groove portion 24a, the incident light 18 that enters the effective pixel region 19 near the boundary between the effective pixel region 19 and the OPB pixel region 20, passes through the effective pixel region 19, and enters the OPB pixel region 20 through the effective pixel region 19, can be weakened by the pixel separation portion 22 (light-shielding material 25) formed by the first linear groove portion 24a. The linear grooves 24 other than the first linear groove 24a, i.e., the second linear groove 24b and the third linear groove 24c, have the same depth. The insulating film 13 is embedded in the second linear groove 24b and the third linear groove 24c. That is, the light-shielding material 25 is embedded only in the first linear groove 24a, and is not embedded in the linear grooves 24 other than the first linear groove 24a (the second linear groove 24b and the third linear groove 24c).

[0021] Here, in the first embodiment, the depth of the first linear groove portion 24a is made deeper than the depth of the third linear groove portion 24c, so that the dark current generated at the interface between the first linear groove portion 24a and the photoelectric conversion portion 17 of the effective pixel region 19 becomes larger than the dark current generated at the interface between the third linear groove portion 24c and the photoelectric conversion portion 17. Therefore, the pixel signal obtained from the photoelectric conversion portion 17 of the effective pixel region 19 adjacent to the OPB pixel region 20 cannot be used. That is, the pixel 9 of the effective pixel region 19 adjacent to the OPB pixel region 20 is an unusable pixel. Similarly, the pixel 9 of the OPB pixel region 20 adjacent to the effective pixel region 19 is also an unusable pixel.

[0022] In the first embodiment, an example is shown in which the shape (depth) of the first linear groove portion 24a is different from the shape (depth) of the third linear groove portion 24c, but other configurations can also be adopted. For example, the shape of any one of the linear groove portions 24 (hereinafter also referred to as "specific linear groove portion 26") among the plurality of linear groove portions 24 constituting the trench portion 23, the first linear groove portion 24a, or the plurality of second linear groove portions 24b formed in the OPB pixel region 20 and parallel to the boundary between the effective pixel region 19 and the OPB pixel region 20 in a plan view, may be different from the shape of the third linear groove portion 24c.

[0023] Specifically, as shown in FIG. 3, the specific straight groove portion 26 may be configured to include only one of the plurality of second straight groove portions 24b without including the first straight groove portion 24a. In this case, the depth of the first straight groove portion 24a is set to be the same as the depth of the third straight groove portion 24c (the straight groove portion 24 of the effective pixel region 19). This makes it possible to make the dark current generated at the interface between the first straight groove portion 24a and the photoelectric conversion portion 17 of the effective pixel region 19 approximately the same as the dark current generated at the interface between the third straight groove portion 24c and the photoelectric conversion portion 17 of the effective pixel region 19. Therefore, the pixel signal obtained from the photoelectric conversion portion 17 of the effective pixel region 19 adjacent to the OPB pixel region 20 can be used in the same way as the pixel signal obtained from the photoelectric conversion portion 17 of the effective pixel region 19 that is not adjacent to the boundary. That is, the pixel 9 of the effective pixel region 19 adjacent to the OPB pixel region 20 becomes a usable pixel. As a result, it is possible to prevent the effective pixel region 19 from being reduced in size. FIG. 3 illustrates an example in which the second straight groove portion 24b closest to the first straight groove portion 24a is set as the specific straight groove portion 26.

[0024] Also, for example, as shown in FIG. 4, the specific straight groove portion 26 may be configured to be any two or more of the first straight groove portion 24a and the multiple second straight groove portions 24b. This can further weaken the incident light 18 that passes through the effective pixel region 19 and enters the OPB pixel region 20, and can reduce the number of pixels 9 that cannot be used to obtain a reference signal for the optical black level. FIG. 4 illustrates a case in which the first straight groove portion 24a and the second straight groove portion 24b closest to the first straight groove portion 24a are used as the specific straight groove portion 26. FIG. 4 also illustrates a case in which the width of the photoelectric conversion portion 17 (pixel 9) of the OPB pixel region 20 adjacent to the specific straight groove portion 26 is narrowed by providing two specific straight groove portions 26 (wide groove portions). When there are two or more specific straight grooves 26, for example, the light-shielding material 25 embedded in the specific straight groove 26 closest to the effective pixel region 19 may be a first material 25a that reflects light, and the light-shielding material 25 embedded in the other specific straight grooves 26 may be a second material 25b that absorbs light. For example, aluminum (Al) or ruthenium (Ru) may be used as the first material 25a. For example, tungsten (W) or titanium (Ti) may be used as the second material 25b. This allows the incident light 18 that passes through the effective pixel region 19 and enters the OPB pixel region 20 to be reflected back to the effective pixel region 19, and the reduction in the charge generated in the photoelectric conversion unit 17 of the effective pixel region 19 adjacent to the OPB pixel region 20 can be suppressed. In addition, it is possible to prevent reflection of incident light 18 that passes through the specific straight groove portion 26 closest to the effective pixel area 19 and enters the OPB pixel area 20, and to suppress an increase in the charge generated in the photoelectric conversion section 17 of the OPB pixel area 20 due to the reflected incident light 18.

[0025] Incidentally, for example, in a method in which the light-shielding material 25 of the specific straight groove portion 26 closest to the effective pixel region 19 is the second material 25b, the charge generated in the photoelectric conversion portion 17 of the effective pixel region 19 adjacent to the OPB pixel region 20 is reduced. Also, for example, in a method in which the light-shielding material 25 of the other specific straight groove portions 26 is the first material 25a, the incident light 18 that passes through the specific straight groove portion 26 closest to the effective pixel region 19 and enters the OPB pixel region 20 is reflected, and the charge generated in the photoelectric conversion portion 17 of the OPB pixel region 20 by the reflected incident light 18 is increased.

[0026] In the first embodiment, for example, as shown in FIG. 2A, in addition to deepening the depth of the specific straight groove portion 26, the width of the specific straight groove portion 26 may be wider than the width of the third straight groove portion 24c. Also, for example, the depth of the specific straight groove portion 26 may not be deepened, and only the width of the specific straight groove portion 26 may be wider (wider than the width of the third straight groove portion 24c). This can further improve the light shielding property of the specific straight groove portion 26, and can more reliably weaken the incident light 18 that penetrates into the OPB pixel region 20 through the specific straight groove portion 26. In addition, it becomes easier to fill the light shielding material 25 inside the specific straight groove portion 26, and it is possible to prevent voids (air gaps) from occurring in the light shielding material 25. In particular, this is suitable for a solid-state imaging device 1 in which the photoelectric conversion portion 17 is deep (the substrate 2 is thick) and the trench portion 23 is formed deeper in order to detect IR (infrared). In addition, since only the specific straight groove portion 26 is made wider, warping of the substrate 2 can be suppressed. FIG. 2A illustrates a case in which the width of the photoelectric conversion section 17 (pixel 9) in the OPB pixel region 20 adjacent to the specific straight groove section 26 is narrowed as the width of the specific straight groove section 26 is increased. Incidentally, for example, if the width of all of the straight grooves 24 constituting the trench portion 23 is increased, the width of the opening side of the straight grooves 24 increases, causing warping of the substrate 2. In addition, the area of ​​the light receiving surface side of the photoelectric conversion portion 17 decreases, reducing the sensitivity of the photoelectric conversion portion 17.

[0027] The insulating film 13 continuously covers the sidewall surfaces and bottom surfaces of the linear groove portions 24 and the entire back surface S1 side (the entire light-receiving surface side) of the substrate 2. The insulating film 13 may be formed by laminating a large number of fixed charge films or the like having negative charges that can generate fixed charges and strengthen pinning. The light-shielding film 14 continuously covers the entire back surface S2 side (the entire light-receiving surface side) of the insulating film 13. Specifically, in the effective pixel region 19, the light-shielding film 14 is formed in a lattice shape so as to open the light-receiving surface of each photoelectric conversion unit 17. In the OPB pixel region 20, there are no openings corresponding to the light-receiving surfaces of the photoelectric conversion units 17, and light is completely blocked. Examples of materials that can be used for the light-shielding film 14 include metals such as aluminum (Al), tungsten (W), and copper (Cu). Planarization film 15 continuously covers the entire back surface S2 side (the entire light receiving surface side) of insulating film 13 including light shielding film 14. This makes back surface S1 of light receiving layer 16 a flat surface without irregularities. Planarization film 15 can be made of an organic material such as a resin.

[0028] In the solid-state imaging device 1 of the first embodiment, a light collecting layer 29 made of a color filter 27 and a microlens 28 (on-chip lens) laminated in this order is formed on a portion of the surface of the light receiving layer 16 facing the planarization film 15 (hereinafter also referred to as the "rear surface S3") that corresponds to the effective pixel region 19. Furthermore, a wiring layer 30 and a support substrate 31 are laminated in this order over the entire surface of the light receiving layer 16 facing the substrate 2 (hereinafter also referred to as the "front surface S4"). The color filters 27 are formed on the rear surface S3 side (light receiving surface side) of the planarization film 15 in correspondence with each photoelectric conversion unit 17. That is, one color filter 27 is formed for one photoelectric conversion unit 17. As a result, the color filters 27 are regularly arranged in a two-dimensional array to form a color filter array 32. Each of the color filters 27 transmits a specific wavelength of the incident light 18 that is to be received by each photoelectric conversion unit 17, such as red R, green G, or blue B, and allows the transmitted incident light 18 to enter the photoelectric conversion unit 17.

[0029] The microlenses 28 are formed on the back surface S5 side (light receiving surface side) of the color filter 27 in correspondence with each photoelectric conversion unit 17. That is, one microlens 28 is formed for one photoelectric conversion unit 17. As a result, the microlenses 28 are regularly arranged in a two-dimensional array to form a microlens array 33. Each of the microlenses 28 is configured to collect image light (incident light 18) from a subject and guide the collected incident light 18 to the vicinity of the back surface (light receiving surface) of the photoelectric conversion unit 17 via the color filter 27.

[0030] The wiring layer 30 is formed on the surface S4 side of the substrate 2, and includes an interlayer insulating film 34 and wirings 35 stacked in multiple layers with the interlayer insulating film 34 interposed therebetween. The wiring layer 30 drives pixel transistors that configure each pixel 9 via the multiple layers of wirings 35. The support substrate 31 is formed on the surface of the wiring layer 30 opposite to the surface facing the substrate 2. The support substrate 31 is a substrate for ensuring the strength of the substrate 2 during the manufacturing stage of the solid-state imaging device 1. The support substrate 31 may be made of, for example, silicon (Si).

[0031] As described above, in the solid-state imaging device 1 of the first embodiment, among the plurality of linear grooves 24 constituting the trench portion 23, the specific linear groove portion 26, which is either the first linear groove portion 24a formed at the boundary between the effective pixel region 19 and the optical black pixel region 20 (OPB pixel region 20) or the plurality of second linear groove portions 24b formed in the OPB pixel region 20 and parallel to the boundary in a plan view, is configured to have a different shape from the third linear groove portion 24c formed between the photoelectric conversion portions 17 in the effective pixel region 19 and to have a light-shielding material 25 embedded therein. As a result, for example, by making the shape of the specific linear groove portion 26 to have a better light-shielding property than the shape of the third linear groove portion 24c, the incident light 18 that passes through the effective pixel region 19 and enters the OPB pixel region 20 near the boundary between the effective pixel region 19 and the OPB pixel region 20 can be weakened by the pixel separation portion 22 constituted by the specific linear groove portion 26. Therefore, the number of rows of the photoelectric conversion units 17 (pixels 9) in the OPB pixel region 20, to which the incident light 18 from the effective pixel region 19 reaches, can be reduced. That is, the number of rows of the pixels 9 (invalid pixels 9) that cannot be used to acquire a reference signal for the optical black level can be reduced. Specifically, the number of invalid pixels 9 arranged between the effective pixel region 19 and the OPB pixels 9 (pixels 9 used to acquire a reference signal) that conventionally required 10 to 20 rows can be reduced to 2 to 3 rows. As a result, the OPB pixel region 20 can be reduced, the chip area can be reduced, and the manufacturing cost can be reduced. Alternatively, the effective pixel region 19 can be expanded by the amount of reduction of the OPB pixel region 20 while maintaining the chip area.

[0032] 2. Second embodiment: solid-state imaging device [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 according to the second embodiment is the same as that in Fig. 1, and therefore will not be illustrated. Fig. 5 is a cross-sectional configuration diagram of a main part of the solid-state imaging device 1 according to the second embodiment. In Fig. 5, parts corresponding to those in Fig. 2A are given the same reference numerals, and duplicated explanations will be omitted.

[0033] The solid-state imaging device 1 according to the second embodiment differs from the solid-state imaging device 1 according to the first embodiment in the configuration of the pixel separation section 22. In the second embodiment, as shown in FIG. 5, each of the multiple linear grooves 24 (first linear groove 24a, second linear groove 24b, and third linear groove 24c) constituting the trench section 23 is formed penetrating the substrate 2. That is, the depth of all the linear grooves 24 is the same. Also, the width of the specific linear groove 26 is wider than the width of the third linear groove 24c. FIG. 5 illustrates a configuration in which the first linear groove 24a is the specific linear groove 26. Also, the light-shielding material 25 is embedded only in the specific linear groove 26, and is not embedded in the linear grooves 24 other than the specific linear groove 26.

[0034] As described above, in the solid-state imaging device 1 of the second embodiment, each of the linear grooves 24 is formed penetrating the substrate 2, and the width of the specific linear groove 26 is wider than the width of the third linear groove 24c. This can further improve the light-shielding property of the specific linear groove 26, and can more reliably weaken the incident light 18 that penetrates into the OPB pixel region 20 through the specific linear groove 26. In addition, it becomes easier to fill the light-shielding material 25 inside the specific linear groove 26, and it is possible to prevent voids (air gaps) from occurring in the light-shielding material 25. In addition, since only the specific linear groove 26 is made wider, warping of the substrate 2 can be suppressed. Incidentally, for example, if the width of all of the straight grooves 24 constituting the trench portion 23 is increased, the width of the opening side of the straight grooves 24 increases, causing warping of the substrate 2. In addition, the area of ​​the light receiving surface side of the photoelectric conversion portion 17 decreases, reducing the sensitivity of the photoelectric conversion portion 17.

[0035] Furthermore, in the solid-state imaging device 1 of the second embodiment, since all the straight grooves 24 have the same depth, the dark current generated at the interface between the first straight groove 24a and the photoelectric conversion section 17 of the effective pixel region 19 is approximately the same as the dark current generated at the interface between the third straight groove 24c and the photoelectric conversion section 17. Therefore, the pixel signal obtained from the photoelectric conversion section 17 of the effective pixel region 19 adjacent to the OPB pixel region 20 can be used. That is, the pixels 9 of the effective pixel region 19 adjacent to the OPB pixel region 20 become pixels 9 that can be used to obtain pixel signals (hereinafter also referred to as "effective pixels 9"). As a result, the effective pixel region 19 can be maintained while the effective pixel region 19 is increased.

[0036] [2-2 Modified Example] In the first and second embodiments, the shape of the light receiving surface side of the photoelectric conversion unit 17 is rectangular, but other configurations can be adopted. For example, it may be octagonal as shown in Fig. 6A, or circular as shown in Fig. 6B. When the shape of the light receiving surface side of the photoelectric conversion unit 17 is octagonal or circular, the side surface of the linear groove portion 24 constituting the trench portion 23 has an uneven shape that follows the side surface of the octagonal or circular photoelectric conversion unit 17.

[0037] 3. Application examples to electronic devices The technology according to the present disclosure (the present technology) may be applied to various electronic devices such as imaging devices such as digital still cameras and digital video cameras, mobile phones with imaging functions, or other devices with imaging functions. FIG. 7 is a diagram showing an example of a schematic configuration of an electronic device (for example, a camera) to which the technology according to the present disclosure (the present technology) can be applied. As shown in FIG. 7, the electronic device 100 includes a solid-state imaging device 101, an optical lens 102, a shutter device 103, a drive circuit 104, and a signal processing circuit 105.

[0038] The optical lens 102 focuses image light (incident light 106) from a subject on the imaging surface of the solid-state imaging device 101. This causes signal charges to accumulate in the solid-state imaging device 101 for a certain period of time. The shutter device 103 controls the light irradiation period and light blocking period of the solid-state imaging device 101. The drive circuit 104 supplies a drive signal that controls the transfer operation of the solid-state imaging device 101 and the shutter operation of the shutter device 103. The drive signal (timing signal) supplied from the drive circuit 104 transfers signals from the solid-state imaging device 101. The signal processing circuit 105 performs various signal processing on signals (pixel signals) output from the solid-state imaging device 101. The video signal that has undergone signal processing is stored in a storage medium such as a memory, or output to a monitor. The electronic device 100 to which the solid-state imaging device 1 can be applied is not limited to a camera, but may be applied to other electronic devices. For example, the solid-state imaging device 1 may be applied to an imaging device such as a camera module for a mobile device such as a mobile phone or a tablet terminal.

[0039] An example of an electronic device to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the solid-state imaging device 101 among the configurations described above. Specifically, the solid-state imaging device 1 in FIG. 1 can be applied to the solid-state imaging device 101. By applying the technology according to the present disclosure to the solid-state imaging device 101, a better captured image can be obtained.

[0040] The present technology can be configured as follows. (1) A pixel region formed on a substrate and including a plurality of photoelectric conversion units arranged in an array; a pixel separating section including a trench section formed in a lattice shape between the photoelectric conversion sections, the pixel region is partitioned into an effective pixel region having the photoelectric conversion unit for obtaining a pixel signal corresponding to incident light, and an optical black pixel region adjacent to the effective pixel region, the light receiving surface side of which is covered with a light shielding film, and the optical black pixel region having the photoelectric conversion unit for obtaining a reference signal of an optical black level; Among the plurality of linear grooves constituting the trench portion, a specific linear groove, which is either a first linear groove formed at the boundary between the effective pixel region and the optical black pixel region or a plurality of second linear grooves formed in the optical black pixel region and parallel to the boundary in a plan view, has a shape different from that of a third linear groove formed between pixels in the effective pixel region, and has a light-shielding material embedded therein. Solid-state imaging device. (2) The depth of the specific straight groove portion is greater than the depth of the third straight groove portion. The solid-state imaging device according to (1) above. (3) The specific straight groove portion does not include the first straight groove portion, and includes only any one of the plurality of second straight groove portions. The solid-state imaging device according to (2) above. (4) The width of the specific linear groove portion is wider than the width of the third linear groove portion. A solid-state imaging device according to any one of (1) to (3). (5) Each of the linear grooves is formed penetrating the substrate, The width of the specific linear groove portion is wider than the width of the third linear groove portion. The solid-state imaging device according to (1) above. (6) The specific straight groove portion is any two or more of the first straight groove portion and the plurality of second straight groove portions. A solid-state imaging device according to any one of (1) to (5). (7) The light-shielding material embedded in the specific straight groove portion closest to the effective pixel area is a first material that reflects light, and the light-shielding materials embedded in the other specific straight groove portions are a second material that absorbs light. The solid-state imaging device according to (6) above. (8) The light-shielding material is aluminum, tungsten or copper. A solid-state imaging device according to any one of (1) to (6). (9) a pixel region formed on a substrate and having a plurality of photoelectric conversion units arranged in an array; and a pixel separation unit including trenches formed in a lattice shape between the photoelectric conversion units, the pixel region being partitioned into an effective pixel region having the photoelectric conversion units for obtaining pixel signals corresponding to incident light, and an optical black pixel region adjacent to the effective pixel region, the light receiving surface side of which is covered with a light shielding film, and having the photoelectric conversion units for obtaining a reference signal for an optical black level, and a plurality of linear grooves constituting the trench portion, the specific linear groove being any one of a first linear groove portion formed at the boundary between the effective pixel region and the optical black pixel region and a plurality of second linear grooves formed in the optical black pixel region and parallel to the boundary in a plan view, has a different shape from a third linear groove portion formed between pixels in the effective pixel region, and has a light shielding material embedded therein; an optical lens that forms an image of image light from a subject on an imaging surface of the solid-state imaging device; a signal processing circuit for performing signal processing on a signal output from the solid-state imaging device; electronic equipment. [Explanation of symbols]

[0041] 1...solid-state imaging device, 2...substrate, 3...pixel region, 4...vertical drive circuit, 5...column signal processing circuit, 6...horizontal drive circuit, 7...output circuit, 8...control circuit, 9...pixel (effective pixel, OPB pixel), 10...pixel drive wiring, 11...vertical signal line, 12...horizontal signal line, 13...insulating film, 14...light-shielding film, 15...planarization film, 16...light-receiving layer, 17...photoelectric conversion section, 18...incident light, 19...effective pixel region, 20...optical black pixel region (OPB pixel region), 21a, 21b, 21c, 21d...pixel row, 22...pixel separation section, 23...trench section, 24... Linear groove portion, 24a...first linear groove portion, 24b...second linear groove portion, 24c...third linear groove portion, 25...light-shielding material, 25a...first material, 25b...second material, 26...specific linear groove portion, 27...color filter, 28...microlens, 29...light-collecting layer, 30...wiring layer, 31...support substrate, 32...color filter array, 33...microlens array, 34...interlayer insulating film, 35...wiring, 100...electronic device, 101...solid-state imaging device, 102...optical lens, 103...shutter device, 104...drive circuit, 105...signal processing circuit, 106...incident light

Claims

1. A pixel region formed on a substrate and including a plurality of photoelectric conversion units arranged in an array; a pixel separating section including a trench section formed in a lattice shape between the photoelectric conversion sections, the pixel region is partitioned into an effective pixel region having the photoelectric conversion unit for obtaining a pixel signal corresponding to incident light, and an optical black pixel region adjacent to the effective pixel region, the light receiving surface side of which is covered with a light shielding film, and the optical black pixel region having the photoelectric conversion unit for obtaining a reference signal of an optical black level; a specific linear groove portion, which is any one of a first linear groove portion formed on the boundary between the effective pixel region and the optical black pixel region and a plurality of second linear groove portions formed in the optical black pixel region and parallel to the boundary in a plan view, among the plurality of linear groove portions constituting the trench portion, has a shape different from a third linear groove portion formed between pixels in the effective pixel region, and has a light-shielding material embedded therein; The depth of the specific linear groove portion is deeper than the depth of the third linear groove portion, The specific linear groove portion does not include the first linear groove portion, and includes only any one of the plurality of second linear groove portions. Solid-state imaging device.

2. The width of the specific linear groove portion is wider than the width of the third linear groove portion. The solid-state imaging device according to claim 1 .

3. A pixel region formed on a substrate and having a plurality of photoelectric conversion units arranged in an array; a pixel separating section including a trench section formed in a lattice shape between the photoelectric conversion sections, the pixel region is partitioned into an effective pixel region having the photoelectric conversion unit for obtaining a pixel signal corresponding to incident light, and an optical black pixel region adjacent to the effective pixel region, the light receiving surface side of which is covered with a light shielding film, and the optical black pixel region having the photoelectric conversion unit for obtaining a reference signal of an optical black level; a specific linear groove portion, which is any one of a first linear groove portion formed on the boundary between the effective pixel region and the optical black pixel region and a plurality of second linear groove portions formed in the optical black pixel region and parallel to the boundary in a plan view, among the plurality of linear groove portions constituting the trench portion, has a shape different from a third linear groove portion formed between pixels in the effective pixel region, and has a light-shielding material embedded therein; The specific linear groove portion is any two or more of the first linear groove portion and the plurality of second linear groove portions. Solid-state imaging device.

4. The light-shielding material embedded in the specific straight groove portion closest to the effective pixel area is a first material that reflects light, and the light-shielding materials embedded in the other specific straight groove portions are a second material that absorbs light. The solid-state imaging device according to claim 3 .

5. The light-shielding material is aluminum, tungsten or copper. The solid-state imaging device according to claim 1 .

6. The pixel region is formed on a substrate and has a plurality of photoelectric conversion units arranged in an array, and a pixel separation unit including a trench portion formed in a lattice shape between the photoelectric conversion units, the pixel region being partitioned into an effective pixel region having the photoelectric conversion units for obtaining a pixel signal corresponding to incident light, and an optical black pixel region adjacent to the effective pixel region, the light receiving surface side of which is covered with a light shielding film, and the optical black pixel region having the photoelectric conversion units for obtaining a reference signal for an optical black level, and among a plurality of linear grooves constituting the trench portion, a linear groove portion between the effective pixel region and the optical black pixel region is formed. a specific linear groove portion, which is any one of a first linear groove portion formed at a boundary between the effective pixel region and an optical black pixel region and a plurality of second linear groove portions formed in the optical black pixel region and parallel to the boundary in a plan view, has a shape different from a third linear groove portion formed between pixels in the effective pixel region and has a light-shielding material embedded therein, the specific linear groove portion is deeper than the third linear groove portion, and the specific linear groove portion does not include the first linear groove portion but includes only any one of the plurality of second linear groove portions; an optical lens that forms an image of image light from a subject on an imaging surface of the solid-state imaging device; a signal processing circuit for performing signal processing on a signal output from the solid-state imaging device; electronic equipment.

7. A solid-state imaging device comprising: a pixel region formed on a substrate and having a plurality of photoelectric conversion units arranged in an array; and a pixel separation section including trench sections formed in a lattice pattern between the photoelectric conversion units, the pixel region being partitioned into an effective pixel region having the photoelectric conversion units for obtaining a pixel signal corresponding to incident light, and an optical black pixel region adjacent to the effective pixel region, the light receiving surface side of which is covered with a light-shielding film, and having the photoelectric conversion units for obtaining a reference signal for an optical black level, wherein a specific linear groove portion among a plurality of linear groove portions constituting the trench portion is any one of a first linear groove portion formed at the boundary between the effective pixel region and the optical black pixel region and a plurality of second linear groove portions formed within the optical black pixel region and parallel to the boundary in a plan view, the specific linear groove portion having a shape different from a third linear groove portion formed between pixels in the effective pixel region and having a light-shielding material embedded therein; an optical lens that forms an image of image light from a subject on an imaging surface of the solid-state imaging device; a signal processing circuit for performing signal processing on a signal output from the solid-state imaging device; electronic equipment.

Images