Solid-state imaging device and electronic apparatus

Abstract

The present invention provides a solid-state imaging device capable of reducing incident light that passes through an effective pixel region and intrudes into an optical black pixel region. The present invention is configured such that, among a plurality of straight groove portions constituting a channel portion, a first straight groove portion is formed at a boundary between the effective pixel region and the optical black pixel region (OPB pixel region), a plurality of second straight groove portions are formed within the OPB region and are parallel to the boundary in a plan view, and a third straight groove portion is formed between photoelectric conversion portions within the effective pixel region. A specific straight groove portion is at least one of the first straight groove portion and / or the plurality of second straight groove portions, the specific straight groove portion is formed to have a shape different from that of the third straight groove portion, and a light-shielding material is buried inside the specific straight groove portion.

Description

Technical Field

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

[0002] In the past, a solid-state imaging device having an effective pixel region and an optical black (hereinafter also referred to as "OPB pixel region") pixel region has been proposed, in which the optical black pixel region is adjacent to the effective pixel region and the light receiving surface side of the optical black pixel region is shielded by a light shielding film (for example, refer to Patent Document 1). The solid-state imaging device described in Patent Document 1 uses pixels in the OPB pixel region to obtain a reference signal for the optical black level.

[0003] Citation List

[0004] Patent Document

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. JP 2013-211413 A Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] Incidentally, near the boundary between the effective pixel region and the OPB pixel region, since the incident light incident on the effective pixel region is inclined and travels toward the OPB pixel region, the incident light passes through the effective pixel region and intrudes into the OPB pixel region. Therefore, the pixels used for obtaining the reference signal (hereinafter also referred to as "OPB pixels") need to be sufficiently separated from the boundary between the effective pixel region and the OPB pixel region. Thus, dummy pixels whose pixel signals are not used need to be arranged between the effective pixel region and the OPB pixels. There are approximately 10 to 20 rows of dummy pixels. As a result, the OPB pixel region is enlarged, the chip area is enlarged, and the manufacturing cost is increased. Alternatively, the effective pixel region needs to be reduced by the enlarged amount of the OPB pixel region.

[0008] An object of the present invention is to provide a solid-state imaging device and an electronic device capable of attenuating incident light that passes through the effective pixel region and intrudes into the optical black pixel region.

[0009] Technical Solution for Solving the Technical Problem

[0010] A solid-state imaging device according to the present invention, (a) includes a pixel region formed on a substrate and including a plurality of photoelectric conversion portions arranged in an array; and (b) further includes a pixel separation portion including channel portions formed in a lattice shape between the photoelectric conversion portions; (c) wherein the pixel region is divided into an effective pixel region and an optical black pixel region, the effective pixel region includes the photoelectric conversion portions for obtaining pixel signals corresponding to incident light, the optical black pixel region is adjacent to the effective pixel region, a light receiving surface side of the optical black pixel region is covered with a light-shielding film, and the optical black pixel region includes the photoelectric conversion portions for obtaining reference signals of optical black levels; and (d) among a plurality of straight groove portions constituting the channel portions, a first straight groove portion is formed at a boundary between the effective pixel region and the optical black pixel region, a plurality of second straight groove portions are formed in the optical black pixel region and are parallel to the boundary in a plan view, a third straight groove portion is formed between pixels in the effective pixel region, a specific straight groove portion is at least one of the first straight groove portion and / or the plurality of second straight groove portions, the specific straight groove portion has a shape different from that of the third straight groove portion, and a light-shielding material is embedded inside the specific straight groove portion.

[0011] In addition, the electronic device of the present invention includes (a) a solid-state imaging device, (b) an optical lens, and (c) a signal processing circuit. The solid-state imaging device includes a pixel region and a pixel separation portion. The pixel region is formed on a substrate and includes a plurality of photoelectric conversion portions arranged in an array. The pixel separation portion includes channel portions formed in a lattice pattern between the photoelectric conversion portions. The pixel region is divided into an effective pixel region and an optical black pixel region. The effective pixel region includes the photoelectric conversion portions for obtaining pixel signals corresponding to incident light, and the optical black pixel region is adjacent to the effective pixel region. The light-receiving surface side of the optical black pixel region is covered with a light-shielding film, and the optical black pixel region includes the photoelectric conversion portions for obtaining reference signals of optical black levels. Among the plurality of straight groove portions constituting the channel portions, a first straight groove portion is formed at the boundary between the effective pixel region and the optical black pixel region, a plurality of second straight groove portions are formed within the optical black pixel region and are parallel to the boundary in a plan view, and a third straight groove portion is formed between pixels within the effective pixel region. A specific straight groove portion is at least one of the first straight groove portion and / or the plurality of second straight groove portions. The specific straight groove portion has a shape different from that of the third straight groove portion, and a light-shielding material is buried inside the specific straight groove portion. The optical lens is configured to form image light from a subject on the imaging surface of the solid-state imaging device. The signal processing circuit is configured to perform signal processing on signals output from the solid-state imaging device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a diagram showing the overall configuration of a solid-state imaging device according to a first embodiment.

[0013] Figure 2A is a diagram showing the cross-sectional structure of a pixel region when cut along line A-A Figure 1 of.

[0014] Figure 2B is a diagram showing the cross-sectional structure of a pixel region when cut along line B-B Figure 2A of.

[0015] Figure 3 is a diagram showing the cross-sectional structure of a pixel region according to a modification.

[0016] Figure 4 is a diagram showing the cross-sectional structure of a pixel region according to a modification.

[0017] Figure 5 is a diagram showing the cross-sectional structure of a pixel region according to a second embodiment.

[0018] Figure 6A This is a diagram showing the shape of the photoelectric conversion section according to a modified example.

[0019] Figure 6B This is a diagram showing the shape of the photoelectric conversion section according to a modified example.

[0020] Figure 7 This is a diagram showing an example of the schematic configuration of an electronic device. Specific Embodiments

[0021] Hereinafter, examples of the solid-state imaging device 1 and the electronic device according to the embodiments of the present invention will be described with reference to Figures 1 to 7 Examples of the solid-state imaging device 1 and the electronic device according to the embodiments of the present invention will be described below in the following order. However, the present invention is not limited to the following examples. In addition, the effects described in this specification are exemplary and not restrictive, and there may be other effects.

[0022] 1. First Embodiment: Solid-State Imaging Device

[0023] 1-1 Overall Configuration of the Solid-State Imaging Device

[0024] 1-2 Configuration of Main Parts

[0025] 2. Second Embodiment: Solid-State Imaging Device

[0026] 2-1 Configuration of Main Parts

[0027] 2-2 Modified Example

[0028] 3. Application Example of the Electronic Device

[0029] <1. First Embodiment: Solid-State Imaging Device>

[0030] [1-1 Overall Configuration of the Solid-State Imaging Device]

[0031] The solid-state imaging device 1 according to the first embodiment of the present invention will be described below. Figure 1 This is a schematic configuration diagram showing the entire solid-state imaging device 1 according to the first embodiment of the present invention.

[0032] Figure 1 The solid-state imaging device 1 is a back-illuminated CMOS (Complementary Metal Oxide Semiconductor) image sensor. As Figure 7 shown, the solid-state imaging device 1 (101) captures image light (incident light 106) from a subject through an optical lens 102, converts the amount of incident light 106 imaged on the imaging surface into an electrical signal in units of pixels, and outputs the electrical signal as a pixel signal.

[0033] As Figure 1 shown, 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.

[0034] The pixel region 3 includes a plurality of pixels 9 arranged in a two-dimensional array on the substrate 2. The pixel 9 includes: Figure 2A and Figure 2B the photoelectric conversion section 17 shown; and a plurality of pixel transistors (not shown). As the plurality of pixel transistors, for example, four types of transistors such as a transfer transistor, a reset transistor, a selection transistor, and an amplifier transistor can be employed. In addition, for example, three types of transistors other than the selection transistor can be used.

[0035] The vertical drive circuit 4 is constituted by, for example, a shift register, which selects a desired pixel drive wiring 10, supplies a pulse for driving the pixel 9 to the selected pixel drive wiring 10, and drives each pixel 9 in units of rows. That is, the vertical drive circuit 4 selectively scans each pixel 9 in the pixel region 3 in the vertical direction in units of rows, and supplies a pixel signal based on signal charges generated corresponding to the amount of light received by the photoelectric conversion section 17 of each pixel 9 to the column signal processing circuit 5 via the vertical signal line 11.

[0036] The column signal processing circuit 5 is arranged corresponding to each column of the pixels 9, for example, and performs signal processing such as noise removal on the signals output from the pixels 9 in one row, pixel column by pixel column. For example, the column signal processing circuit 5 performs signal processing such as correlated double sampling (CDS: Correlated Double Sampling) for removing fixed pattern noise inherent to the pixels and analog-digital (AD) conversion.

[0037] The horizontal drive circuit 6 is constituted by, for example, a shift register, and sequentially outputs horizontal scan pulses to the column signal processing circuit 5, thereby sequentially selecting each of the column signal processing circuits 5, and causing each of the column signal processing circuits 5 to output the pixel signals that have undergone signal processing to the horizontal signal line 12.

[0038] The output circuit 7 performs signal processing on the pixel signals sequentially supplied from each of the column signal processing circuits 5 via the horizontal signal lines 12, and then outputs the pixel signals after the signal processing. For example, as this signal processing, buffering, optical black level adjustment, column difference correction, various digital signal processing, etc. can be employed. As the optical black level adjustment, for example, the following processing can be used: subtracting the reference signal of the optical black level obtained from the pixel 9 in the optical black pixel region 20 from the pixel signal obtained from the pixel 9 in the effective pixel region 19 to correct the black level of the pixel signal to "0".

[0039] The control circuit 8 generates a clock signal or a control signal serving as a reference for the operations 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 main clock signal. Then, the control circuit 8 outputs the generated clock signal or control signal to the vertical drive circuit 4, the column signal processing circuit 5, the horizontal drive circuit 6, etc.

[0040] [Structure of Main Parts 1-2]

[0041] Next, the Figure 1 detailed structure of the solid-state imaging device 1 will be described. Figure 2A is a diagram showing a cross-sectional structure of the pixel region 3 of the solid-state imaging device 1. Figure 2B is a diagram showing a planar structure of the substrate 2 in the case of being cut along the Figure 2A line B-B. In Figure 2A and Figure 2B , a back-illuminated CMOS image sensor (CMOS type solid-state imaging device) is used as the solid-state imaging device 1.

[0042] As Figure 2A and Figure 2B shown, the solid-state imaging device 1 of the first embodiment includes a light receiving layer 16, in which a substrate 2, an insulating film 13, a light shielding film 14, and a planarization film 15 are sequentially stacked.

[0043] The substrate 2 is constituted of, for example, a semiconductor substrate made of silicon (Si), and forms Figure 1 the pixel region 3 shown. In the pixel region 3, as Figure 2A and Figure 2B shown, a plurality of pixels 9 formed by including a plurality of photoelectric conversion portions 17 (i.e., a plurality of photoelectric conversion portions 17 buried in the substrate 2) formed on the substrate 2 are arranged in a two-dimensional array. In the photoelectric conversion portion 17, a signal charge corresponding to the amount of incident light 18 is generated, and the generated signal charge is accumulated.

[0044] In addition, as Figure 1As shown, the pixel region 3 is divided into an effective pixel region 19 and an optically black pixel region 20 (hereinafter, also referred to as the "OPB pixel region 20"). The effective pixel region 19 is a region in which a photoelectric conversion section 17 for obtaining a pixel signal corresponding to incident light 18 is formed. In addition, the OPB pixel region 20 is a region adjacent to the effective pixel region 19. The light receiving surface side of the OPB pixel region 20 is covered with a light shielding film 14, and a photoelectric conversion section 17 for obtaining a pixel signal (hereinafter, also referred to as a "reference signal") of an optically black level is formed in the OPB pixel region 20. Figure 1 An example of a structure is illustrated in which the effective pixel region 19 is located at the center of the pixel region 3 and the OPB pixel region 20 is located at the peripheral portion of the pixel region 3.

[0045] In the case where the OPB pixel region 20 is located at the peripheral portion of the pixel region 3, as the pixels 9 (OPB pixels 9) used when obtaining the reference signal of the optically black level, the following pixel columns of the pixels 9 within the OPB pixel region 20 can be adopted: a plurality of pixel columns 21a arranged at a position far from the upper side of the effective pixel region 19 and parallel to the upper side in a plan view; a plurality of pixel columns 21b arranged at a position far from the lower side of the effective pixel region 19 and parallel to the lower side in a plan view; a plurality of pixel columns 21c arranged at a position far from the left side of the effective pixel region 19 and parallel to the left side in a plan view; and a plurality of pixel columns 21d arranged at a position far from the right side of the effective pixel region 19 and parallel to the right side in a plan view.

[0046] In addition, each photoelectric conversion section 17 is physically separated by a pixel separation section 22. The pixel separation section 22 is formed in a lattice shape so as to surround each photoelectric conversion section 17. The pixel separation section 22 includes a channel section 23 (groove section) formed along the depth direction from the surface (hereinafter, also referred to as the "back surface S1") side of the substrate 2 on the insulating film 13 side. That is, the channel section 23 is formed between the adjacent photoelectric conversion sections 17 on the back surface S1 side of the substrate 2. In addition, similar to the pixel separation section 22, the channel section 23 is formed in a lattice shape so as to surround each photoelectric conversion section 17.

[0047] In addition, among the plurality of straight groove portions 24 that constitute the channel portion 23, the shape of the straight groove portion 24 formed at the boundary between the effective pixel region 19 and the OPB pixel region 20 (hereinafter, also referred to as "first straight groove portion 24a") is different from the shape of the straight groove portion 24 between the photoelectric conversion portion 17 within the effective pixel region 19. Specifically, the depth of the first straight groove portion 24a is greater than the depth of the straight groove portion 24 (hereinafter, also referred to as "third straight groove portion 24c") between the pixels 9 arranged within the effective pixel region 19. In addition, the side wall surface and the bottom surface of the first straight groove portion 24a are covered with the insulating film 13 for covering the back surface S1 side of the substrate 2. The film thickness of the insulating film 13 is the uniform film thickness of the insulating film that forms a space inside the first straight groove portion 24a and thus does not completely fill the inside of the first straight groove portion 24a.

[0048] In addition, the light-shielding material 25 is buried in the space surrounded by the insulating film 13 inside the first straight groove portion 24a. As the light-shielding material 25, metals such as aluminum (Al), tungsten (W), or copper (Cu) can be used. By using aluminum, tungsten, and copper, the light-shielding property can be improved. Thus, by making the depth of the first straight groove portion 24a greater than the depth of the third straight groove portion 24c and burying the light-shielding material 25 in the first straight groove portion 24a, it is possible to weaken the incident light 18 that enters the effective pixel region 19, passes through the effective pixel region 19, and intrudes into the OPB pixel region 20 and that intrudes into the OPB pixel region 20 through the deeper part of the effective pixel region 19 (substrate 2) near the boundary between the effective pixel region 19 and the OPB pixel region 20 by using the pixel separation portion 22 (light-shielding material 25) constituted by the first straight groove portion 24a.

[0049] In addition, the depths of the straight groove portions 24 other than the first straight groove portion 24a (i.e., the second straight groove portion 24b and the third straight groove portion 24c) are the same as each other. In addition, the insulating film 13 is buried in the second straight groove portion 24b and the third straight groove portion 24c. That is, the light-shielding material 25 is only buried in the first straight groove portion 24a and is not buried in the straight groove portions 24 (second straight groove portion 24b and third straight groove portion 24c) other than the first straight groove portion 24a.

[0050] Here, in the first embodiment, since the depth of the first straight groove portion 24a is greater than the depth of the third straight groove portion 24c, 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 is greater than the dark current generated at the interface between the third straight groove portion 24c and the photoelectric conversion portion 17. Thus, the pixel signal obtained from the photoelectric conversion portion 17 within the effective pixel region 19 adjacent to the OPB pixel region 20 cannot be used. That is, the pixel 9 within the effective pixel region 19 adjacent to the OPB pixel region is a pixel that cannot be used. Similarly, the pixel 9 within the OPB pixel region 20 adjacent to the effective pixel region 19 is also a pixel that cannot be used.

[0051] In the first embodiment, an example is shown in which the shape (depth) of the first straight groove portion 24a is different from the shape (depth) of the third straight groove portion 24c, but other configurations may also be adopted. For example, among the plurality of straight groove portions 24 constituting the channel portion 23, a plurality of second straight groove portions 24b are formed within the OPB pixel region 20 and are parallel to the boundary between the effective pixel region 19 and the OPB pixel region 20 in the plan view, and the shape of at least one straight groove portion 24 (hereinafter, also referred to as "specific straight groove portion 26") among the first straight groove portion 24a or the plurality of second straight groove portions 24b may be different from the shape of the third straight groove portion 24c.

[0052] Specifically, as Figure 3 shown, the specific straight groove portion 26 may be configured to not include the first straight groove portion 24a and only include one of the plurality of second straight groove portions 24b. In this case, the depth of the first straight groove portion 24a is the same as the depth of the third straight groove portion 24c (the straight groove portion 24 within the effective pixel region 19). This enables the dark current generated at the interface between the first straight groove portion 24a and the photoelectric conversion portion 17 within the effective pixel region 19 to be substantially the same as the dark current generated at the interface between the third straight groove portion 24c and the photoelectric conversion portion 17 within the effective pixel region 19. Therefore, similar to the pixel signal obtained from the photoelectric conversion portion 17 within the effective pixel region 19 not adjacent to the boundary, the pixel signal obtained from the photoelectric conversion portion 17 within the effective pixel region 19 adjacent to the OPB pixel region 20 can be used. That is, the pixel 9 within the effective pixel region 19 adjacent to the OPB pixel region 20 is an available pixel. As a result, it is possible to prevent the size of the effective pixel region 19 from being reduced. Figure 3 The case where the second straight groove portion 24b closest to the first straight groove portion 24a is the specific straight groove portion 26 is shown.

[0053] In addition, for example, as Figure 4As shown, the specific straight groove portion 26 can be configured to include the first straight groove portion 24a and any two or more of the plurality of second straight groove portions 24b. This makes it possible to further attenuate the incident light 18 that passes through the effective pixel region 19 and penetrates into the OPB pixel region 20, and to reduce the number of pixels 9 that cannot be used to obtain the reference signal for the optical black level. In Figure 4 it shows a case where both the first straight groove portion 24a and the second straight groove portion 24b closest to the first straight groove portion 24a constitute the specific straight groove portion 26. In addition, in Figure 4 it illustrates a case where when two specific straight groove portions 26 (wide groove portions) are provided, the width of the photoelectric conversion portion 17 (pixel 9) in the OPB pixel region 20 adjacent to the specific straight groove portion 26 becomes narrow.

[0054] When there are two or more specific straight groove portions 26, for example, the light-shielding material 25 embedded in the specific straight groove portion 26 closest to the effective pixel region 19 can be the first material 25a capable of reflecting light, and the light-shielding material 25 embedded in the other specific straight groove portions 26 can be the second material 25b capable of absorbing light. For example, as the first material 25a, aluminum (Al) or ruthenium (Ru) can be used. In addition, for example, as the second material 25b, tungsten (W) or titanium (Ti) can be used. This makes it possible to reflect the incident light 18 that passes through the effective pixel region 19 and penetrates into the OPB pixel region 20 back to the effective pixel region 19, and to suppress the reduction of the charge generated by the photoelectric conversion portion 17 in the effective pixel region 19 adjacent to the OPB pixel region 20. In addition, it is also possible to prevent the reflection of the incident light 18 that passes through the specific straight groove portion 26 closest to the effective pixel region 19 and penetrates into the OPB pixel region 20, and to suppress the increase of the charge generated in the photoelectric conversion portion 17 in the OPB pixel region 20 due to the reflected incident light 18.

[0055] Incidentally, for example, in the method where the light-shielding material 25 in 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 in the effective pixel region 19 adjacent to the OPB pixel region 20 is reduced. In addition, for example, in the method where the light-shielding material 25 in 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 penetrates into the OPB pixel region 20 is reflected, and the charge generated in the photoelectric conversion portion 17 in the OPB pixel region 20 due to the reflected incident light 18 increases.

[0056] In addition, in the first embodiment, for example, as Figure 2AAs shown, in addition to increasing the depth of the specific straight groove portion 26, the width of the specific straight groove portion 26 is also greater than the width of the third straight groove portion 24c. In addition, for example, instead of increasing the depth of the specific straight groove portion 26, only the width of the specific straight groove portion 26 can be increased (it can be made greater than the width of the third straight groove portion 24c). This makes it possible to further improve the light-shielding property of the specific straight groove portion 26 and to more reliably attenuate the incident light 18 that enters the OPB pixel region 20 through the specific straight groove portion 26. In addition, this makes it easy to bury the light-shielding material 25 into the specific straight groove portion 26 and to prevent voids from being generated in the light-shielding material 25. In particular, the first embodiment is applicable to a solid-state imaging device 1 in which the photoelectric conversion unit 17 is deep (the substrate 2 is thick) and the channel portion 23 is formed deeply in order to detect infrared rays (IR). In addition, since only the width of the specific straight groove portion 26 is increased, warping of the substrate 2 can be suppressed. In Figure 2A it is shown that when the width of the specific straight groove portion 26 is increased, the width of the photoelectric conversion portion 17 (pixel 9) in the OPB pixel region 20 adjacent to the specific straight groove portion 26 is decreased.

[0057] Incidentally, for example, according to the method of increasing the widths of all the straight groove portions 24 that constitute the channel portion 23, the width of the opening side of the straight groove portion 24 will increase and the substrate 2 will warp. In addition, the area of the light-receiving surface side of the photoelectric conversion portion 17 will become smaller and the sensitivity of the photoelectric conversion portion 17 will decrease.

[0058] The insulating film 13 continuously covers the side wall surface and the bottom surface of the straight groove portion 24 and the entire back surface S1 side (the entire light-receiving surface side) of the substrate 2. The insulating film 13 can be formed by, for example, laminating a plurality of fixed charge thin films having negative charges that can generate fixed charges and can strengthen pinning.

[0059] 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, the light-shielding film 14 is formed in a lattice shape so as to have openings corresponding to the light-receiving surfaces of the respective photoelectric conversions 17 in the effective pixel region 19. In addition, in the OPB pixel region 20, there are no openings corresponding to the light-receiving surfaces of the photoelectric conversion portions 17 and it is completely light-shielded. As the material of the light-shielding film 14, for example, metals such as aluminum (Al), tungsten (W), or copper (Cu) can be used.

[0060] The planarization film 15 continuously covers the entire back surface S2 side (the entire light-receiving surface side) of the insulating film 13 including the light-shielding film 14. Therefore, the back surface S1 side of the light-receiving layer 16 is a flat surface without irregularities. As the material of the planarization film 15, for example, an organic material such as a resin can be used.

[0061] In addition, in the solid-state imaging device 1 of the first embodiment, a condensing layer 29 obtained by sequentially laminating a color filter 27 and a microlens 28 (on-chip lens) is formed on the surface on the flattening film 15 side of the light-receiving layer 16 (hereinafter, also referred to as “back surface S3”) at a portion corresponding to the effective pixel region 19. In addition, a wiring layer 30 and a support substrate 31 are sequentially laminated on the entire surface on the substrate 2 side of the light-receiving layer 16 (hereinafter, also referred to as “front surface S4”).

[0062] The color filter 27 is formed on the back surface S3 side (light-receiving surface side) of the flattening film 15 corresponding to each photoelectric conversion unit 17. That is, one color filter 27 is formed for one photoelectric conversion unit 17. Therefore, a color filter array 32 in which the color filters 27 are regularly arranged in a two-dimensional array is formed by the color filter 27. Each of the color filters 27 is configured to allow a specific wavelength of incident light 18 to be received by each photoelectric conversion unit 17, such as red R, green G, and blue B, to pass through, and to cause the transmitted incident light 18 to be incident on the photoelectric conversion unit 17.

[0063] The microlens 28 is formed on the back surface S5 side (light-receiving surface side) of the color filter 27 corresponding to each photoelectric conversion unit 17. That is, one microlens 28 is formed for one photoelectric conversion unit 17. Therefore, a microlens array 33 in which the microlenses 28 are regularly arranged in a two-dimensional array is formed by the microlens 28. Each of the microlenses 28 is configured to converge image light (incident light 18) from the subject, and to guide the converged incident light 18 to the vicinity of the back surface (light-receiving surface) of the photoelectric conversion unit 17 via the color filter 27.

[0064] The wiring layer 30 is formed on the front surface S4 side of the substrate 2, and is configured to include an interlayer insulating film 34 and wirings 35 laminated in multiple layers with the interlayer insulating film 34 interposed therebetween. The wiring layer 30 drives pixel transistors for constituting each pixel 9 via the multiple-layer wirings 35.

[0065] The support substrate 31 is formed on the surface of the wiring layer 30 on the side opposite to the side facing the substrate 2. The support substrate 31 is a substrate for ensuring the strength of the substrate 2 in the manufacturing stage of the solid-state imaging device 1. As the material of the support substrate 31, for example, silicon (Si) can be used.

[0066] According to the above description, in the solid-state imaging device 1 of the first embodiment, among the plurality of straight groove portions 24 constituting the channel portion 23, the first straight groove portion 24a is formed at the boundary between the effective pixel region 19 and the optical black pixel region 20 (OPB pixel region 20), the plurality of second straight groove portions 24b are formed within the OPB pixel region 20 and are parallel to the above boundary in the plan view, and the third straight groove portion 24c is formed between the photoelectric conversion portions 17 within the effective pixel region 19. Here, the specific straight groove portion 26 is at least one of the first straight groove portion 24a and / or the plurality of second straight groove portions 24b. The specific straight groove portion 26 has a shape different from that of the third straight groove portion 24c, and a light-shielding material 25 is buried inside the specific straight groove portion 26. Therefore, for example, by making the shape of the specific straight groove portion 26 a shape with better light-shielding property compared to the shape of the third straight groove portion 24c, it is possible to weaken the incident light 18 that intrudes into the OPB pixel region 20 through the effective pixel region 19 by using the pixel separation portion 22 constituted by the specific straight groove portion 26 near the boundary between the effective pixel region 19 and the OPB pixel region 20. Therefore, it is possible to reduce the number of rows of the photoelectric conversion portions 17 (pixels 9) in the OPB pixel region 20 that the incident light 18 from the effective pixel region 19 reaches. That is, it is possible to reduce the number of rows of pixels 9 (invalid pixels 9) that cannot be used to obtain the reference signal of the optical black level. Specifically, the number of invalid pixels 9 arranged between the effective pixel region 19 and the OPB pixel 9 (the pixel 9 used when obtaining the reference signal) requires 10 to 20 rows in the prior art, but here there can be only 2 or 3 rows of invalid pixels 9. As a result, the OPB pixel region 20 is reduced, thereby enabling the chip area to be reduced and the manufacturing cost to be lowered. Alternatively, while maintaining the chip area, the effective pixel region 19 can be enlarged according to the reduction amount of the OPB pixel region 20.

[0067] <2. Second Embodiment: Solid-State Imaging Device>

[0068] [2-1 Structure of Main Portion]

[0069] Next, the solid-state imaging device 1 according to the second embodiment of the present invention will be described. Since the overall structure of the solid-state imaging device according to the second embodiment is the same as that in Figure 1 , its illustration is omitted. Figure 5 is a cross-sectional structure diagram of the main portion of the solid-state imaging device 1 according to the second embodiment. In Figure 5 , the parts corresponding to Figure 2A are denoted by the same reference numerals, and repeated descriptions will be omitted.

[0070] In the solid-state imaging device 1 according to the second embodiment, the structure of the pixel separation section 22 is different from that in the solid-state imaging device 1 according to the first embodiment. In the second embodiment, as Figure 5 shown, each of the plurality of straight groove portions 24 (first straight groove portion 24a, second straight groove portion 24b, third straight groove portion 24c) constituting the channel portion 23 is formed to penetrate the substrate 2. That is, the depths of all the straight groove portions 24 are the same. In addition, the width of the specific straight groove portion 26 is larger than the width of the third straight groove portion 24c. In Figure 5 it, the structure in which the first straight groove portion 24a is the specific straight groove portion 26 is shown. In addition, the light-shielding material 25 is buried only in the specific straight groove portion 26 and is not buried in the straight groove portions 24 other than the specific straight groove portion 26.

[0071] As described above, in the solid-state imaging device 1 of the second embodiment, each of the plurality of straight groove portions 24 is formed to penetrate the substrate 2, and the width of the specific straight groove portion 26 is larger than the width of the third straight groove portion 24c. This makes it possible to further improve the light-shielding property of the specific straight groove portion 26 and to more reliably attenuate the incident light 18 that enters the OPB pixel region 20 through the specific straight groove portion 26. In addition, it becomes easy to bury the light-shielding material 25 inside the specific straight groove portion 26, and voids can be prevented from being generated in the light-shielding material 25. In addition, since only the width of the specific straight groove portion 26 is increased, warping of the substrate 2 can be suppressed.

[0072] Incidentally, for example, according to the method of increasing the widths of all the straight groove portions 24 constituting the channel portion 23, the width of the opening side of the straight groove portion 24 is increased and the substrate 2 warps. In addition, the area on the light-receiving surface side of the photoelectric conversion portion 17 becomes smaller, and the sensitivity of the photoelectric conversion portion 17 decreases.

[0073] In addition, in the solid-state imaging device 1 of the second embodiment, since the depths of all the straight groove portions 24 are the same, it is made such that: the dark current generated at the interface between the first straight groove portion 24a and the photoelectric conversion portion 17 in the effective pixel region 19 is substantially the same as the dark current generated at the interface between the third straight groove portion 24c and the photoelectric conversion portion 17. Therefore, the pixel signal obtained from the photoelectric conversion portion 17 in the effective pixel region 19 adjacent to the OPB pixel region 20 can be used. That is, the pixel 9 in the effective pixel region 19 adjacent to the OPB pixel region 20 becomes a pixel 9 that can be used when acquiring a pixel signal (hereinafter, also referred to as "effective pixel 9"). Therefore, while maintaining the effective pixel region 19, the number of effective pixels 9 can be increased.

[0074] [2-2 Modification Example]

[0075] Although an example in which the shape of the light-receiving surface side of the photoelectric conversion unit 17 is a quadrilateral has been shown in the first embodiment and the second embodiment, other configurations may also be adopted. For example, the shape may be an octagon as shown in Figure 6A or may be a circle as shown in Figure 6B . When the shape of the light-receiving surface side of the photoelectric conversion unit 17 is an octagon or a circle, the side surfaces of the straight groove portions 24 constituting the channel portion 23 have a shape with irregularities along the side surfaces of the octagonal or circular photoelectric conversion unit 17.

[0076] <3. Application Examples of Electronic Devices>

[0077] The technology according to the present invention (this technology) can be applied to various electronic devices, such as: imaging devices such as digital cameras and digital video cameras, mobile phones with an imaging function, or other devices with an imaging function.

[0078] Figure 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 invention (this technology) can be applied.

[0079] As shown in Figure 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.

[0080] The optical lens 102 forms an image of the image light (incident light 106) from the subject on the imaging surface of the solid-state imaging device 101. Therefore, signal charges are accumulated in the solid-state imaging device 101 for a certain period. The shutter device 103 controls the light exposure period and the light shielding period of the solid-state imaging device 101. The drive circuit 104 provides drive signals for controlling the transfer operation of the solid-state imaging device 101 and the shutter operation of the shutter device 103. The signal transfer of the solid-state imaging device 101 is performed using the drive signals (timing signals) provided by the drive circuit 104. The signal processing circuit 105 performs various signal processes on the signals (pixel signals) output from the solid-state imaging device 101. The video signal after signal processing is stored in a storage medium such as a memory or output to a monitor.

[0081] The electronic device 100 to which the solid-state imaging device 1 can be applied is not limited to a camera, and the solid-state imaging device 1 can also be applied to other electronic devices. For example, the solid-state imaging device 1 can be applied to imaging devices such as camera modules for mobile devices such as mobile phones or tablet terminals.

[0082] Examples of electronic devices to which the technology according to the present invention can be applied have been described. The technology according to the present invention can be applied to the solid-state imaging device 101 in the above configuration. Specifically, Figure 1The solid-state imaging device 1 can be applied to the solid-state imaging device 101. By applying the technology according to the present invention to the solid-state imaging device 101, better captured images can be obtained.

[0083] The present technology may have the following technical solutions.

[0084] (1) A solid-state imaging device, comprising a pixel region and a pixel separation portion,

[0085] The pixel region is formed on a substrate and includes a plurality of photoelectric conversion portions arranged in an array, and the pixel separation portion includes channel portions formed in a lattice pattern between the photoelectric conversion portions.

[0086] Among them, the pixel region is divided into an effective pixel region and an optical black pixel region. The effective pixel region includes the photoelectric conversion portions for obtaining pixel signals corresponding to incident light, and

[0087] The optical black pixel region is adjacent to the effective pixel region. The light receiving surface side of the optical black pixel region is covered with a light-shielding film, and the optical black pixel region includes the photoelectric conversion portions for obtaining reference signals of optical black levels.

[0088] Among the plurality of straight groove portions constituting the channel portion, a first straight groove portion is formed at the boundary between the effective pixel region and the optical black pixel region. A plurality of second straight groove portions are formed within the optical black pixel region and are parallel to the boundary in a plan view, and a third straight groove portion is formed between the pixels within the effective pixel region.

[0089] A specific straight groove portion is at least one of the first straight groove portion and / or at least one of the plurality of second straight groove portions. The specific straight groove portion has a shape different from that of the third straight groove portion, and a light-shielding material is buried inside the specific straight groove portion.

[0090] (2) The solid-state imaging device according to (1), wherein

[0091] The depth of the specific straight groove portion is greater than the depth of the third straight groove portion.

[0092] (3) The solid-state imaging device according to (2), wherein

[0093] The specific straight groove portion does not include the first straight groove portion and only includes one of the plurality of second straight groove portions.

[0094] (4) The solid-state imaging device according to any one of (1) to (3), wherein

[0095] The width of the specific straight groove portion is greater than the width of the third straight groove portion.

[0096] (5) The solid-state imaging device according to (1), wherein,

[0097] each of the plurality of straight groove portions is formed to penetrate the substrate, and

[0098] the width of the specific straight groove portion is greater than the width of the third straight groove portion.

[0099] (6) The solid-state imaging device according to any one of (1) to (5), wherein,

[0100] the specific straight groove portion includes the first straight groove portion and two or more of the plurality of second straight groove portions.

[0101] (7) The solid-state imaging device according to (6), wherein,

[0102] the light-shielding material buried in the specific straight groove portion closest to the effective pixel region is a first material capable of reflecting light, and

[0103] the light-shielding material buried in the other specific straight groove portions is a second material capable of absorbing light.

[0104] (8) The solid-state imaging device according to any one of (1) to (6), wherein,

[0105] the light-shielding material is aluminum, tungsten or copper.

[0106] (9) An electronic device, comprising a solid-state imaging device, an optical lens and a signal processing circuit,

[0107] the solid-state imaging device includes a pixel region and a pixel separation portion,

[0108] the pixel region is formed on a substrate and includes a plurality of photoelectric conversion portions arranged in an array, and the pixel separation portion includes channel portions formed in a lattice pattern between the photoelectric conversion portions,

[0109] the pixel region is divided into an effective pixel region and an optical black pixel region,

[0110] the effective pixel region includes the photoelectric conversion portions for obtaining pixel signals corresponding to incident light, and

[0111] the optical black pixel region is adjacent to the effective pixel region, the light receiving surface side of the optical black pixel region is covered with a light-shielding film, and the optical black pixel region includes the photoelectric conversion portions for obtaining reference signals of optical black levels,

[0112] Among the plurality of straight groove portions constituting the channel portion, the first straight groove portion is formed at the boundary between the effective pixel region and the optical black pixel region, the plurality of second straight groove portions are formed within the optical black pixel region and are parallel to the boundary in a plan view, and the third straight groove portion is formed between the pixels within the effective pixel region.

[0113] The specific straight groove portion is at least one of the first straight groove portion and / or the plurality of second straight groove portions. The specific straight groove portion has a shape different from that of the third straight groove portion, and a light-shielding material is buried inside the specific straight groove portion.

[0114] The optical lens is configured to form an image of subject light on the imaging surface of the solid-state imaging device, and

[0115] The signal processing circuit is configured to perform signal processing on the signal output from the solid-state imaging device.

[0116] List of Reference Numerals

[0117] 1: Solid-state imaging device

[0118] 2: Substrate

[0119] 3: Pixel region

[0120] 4: Vertical drive circuit

[0121] 5: Column signal processing circuit

[0122] 6: Horizontal drive circuit

[0123] 7: Output circuit

[0124] 8: Control circuit

[0125] 9: Pixel (effective pixel, OPB pixel)

[0126] 10: Pixel drive wiring

[0127] 11: Vertical signal line

[0128] 12: Horizontal signal line

[0129] 13: Insulating film

[0130] 14: Light-shielding film

[0131] 15: Planarization film

[0132] 16: Light-receiving layer

[0133] 17: Photoelectric conversion portion

[0134] 18: Incident light

[0135] 19: Effective pixel area

[0136] 20: Optical black pixel area (OPB pixel area)

[0137] 21a, 21b, 21c, 21d: Multiple pixel columns

[0138] 22: Pixel separation section

[0139] 23: Channel section

[0140] 24: Straight groove section

[0141] 24a: First straight groove section

[0142] 24b: Second straight groove section

[0143] 24c: Third straight groove section

[0144] 25: Light-shielding material

[0145] 25a: First material

[0146] 25b: Second material

[0147] 26: Specific straight groove section

[0148] 27: Color filter

[0149] 28: Microlens

[0150] 29: Condensing layer

[0151] 30: Wiring layer

[0152] 31: Support substrate

[0153] 32: Color filter array

[0154] 33: Microlens array

[0155] 34: Interlayer insulating film

[0156] 35: Wiring

[0157] 100: Electronic device

[0158] 101: Solid-state imaging device

[0159] 102: Optical lens

[0160] 103: Shutter device

[0161] 104: Driving circuit

[0162] 105: Signal processing circuit

[0163] 106: Incident light

Claims

1. A solid-state imaging device, comprising a pixel region and a pixel isolation section, wherein the pixel region is formed on a substrate and includes a plurality of photoelectric conversion sections arranged in an array, and the pixel isolation section includes channel sections formed in a lattice pattern between the photoelectric conversion sections, Among them, the pixel region is divided into an effective pixel region and an optical black pixel region, the effective pixel region includes the photoelectric conversion sections for obtaining pixel signals corresponding to incident light, and the optical black pixel region is adjacent to the effective pixel region, a light-receiving surface side of the optical black pixel region is covered with a light-shielding film, and the optical black pixel region includes the photoelectric conversion sections for obtaining reference signals of optical black levels, among a plurality of straight groove sections constituting the channel section, a first groove section is formed at a boundary between the effective pixel region and the optical black pixel region, a plurality of second groove sections are formed within the optical black pixel region and are parallel to the boundary in a plan view, a third groove section is formed between pixels within the effective pixel region, a specific groove section is at least one of the first groove section and / or the plurality of second groove sections, the specific groove section has a shape different from that of the third groove section, and a part of the specific groove section is buried inside an insulating film.

2. The solid-state imaging device according to claim 1, wherein a depth of the specific groove section is greater than a depth of the third groove section.

3. The solid-state imaging device according to claim 2, wherein the specific groove section does not include the first groove section and includes only one of the plurality of second groove sections.

4. The solid-state imaging device according to claim 1, wherein a width of the specific groove section is greater than a width of the third groove section.

5. The solid-state imaging device according to claim 1, wherein each of the plurality of straight groove sections is formed to penetrate the substrate, and a width of the specific groove section is greater than a width of the third groove section.

6. The solid-state imaging device according to claim 1, wherein the specific groove section includes the first groove section and includes any two or more of the plurality of second groove sections.

7. The solid-state imaging device according to claim 6, wherein a light-shielding material is buried inside the specific groove section.

8. The solid-state imaging device according to claim 7, wherein the light-shielding material buried in the specific groove section closest to the effective pixel region is a first material for reflecting light, and the light-shielding material buried in other specific groove sections is a second material for absorbing light.

9. The solid-state imaging device according to any one of claims 1 to 8, wherein the light-shielding material is aluminum, tungsten, or copper.

10. An electronic device, comprising a solid-state imaging device, an optical lens, and a signal processing circuit, wherein the solid-state imaging device is the solid-state imaging device according to any one of claims 1 to 9, the optical lens is configured to form an image of object light on an imaging surface of the solid-state imaging device, and the signal processing circuit is configured to perform signal processing on signals output from the solid-state imaging device.

Images