Solid-state imaging device and electronic apparatus

Abstract

A solid-state imaging device capable of suppressing color mixture between different colors while reducing sensitivity difference between the same colors is provided. The solid-state imaging device includes: a plurality of photoelectric conversion units formed on a substrate and generating signal charges according to light quantity of incident light; a microlens array including microlenses formed for a photoelectric conversion unit group including at least two or more photoelectric conversion units (21) adjacent to each other and guiding the incident light to the photoelectric conversion unit group; a scatterer arranged on an optical path of the incident light converged by the microlens; and an inter-pixel light shielding portion including a trench and an insulating material filled in the trench, the trench being formed between a photoelectric conversion unit of the photoelectric conversion unit group and a photoelectric conversion unit adjacent to the photoelectric conversion unit group. An opening side of an inner side surface of the trench on the scatterer side is a plane inclined in a manner that a trench width narrows toward a bottom of the trench.

Description

Technical Field

[0001] This technology relates to solid-state imaging devices and electronic devices. Background Technology

[0002] In related technologies, a solid-state imaging device has been proposed that can calculate the distance to the subject based on the signal charge generated by the four photoelectric conversion units sharing a microlens structure (see, for example, Patent Document 1). In the solid-state imaging device disclosed in Patent Document 1, a scatterer is provided at the focusing point of the microlens, causing the converged light to be scattered by the scatterer and distributed to the four adjacent photoelectric conversion units. Furthermore, differences in light receiving sensitivity between photoelectric conversion units (sensitivity differences between the same color) caused by pupil correction, etc., are suppressed.

[0003] Reference List

[0004] Patent documents

[0005] Patent Document 1: JP 2013-211413 A Summary of the Invention

[0006] Technical issues

[0007] However, in the solid-state imaging device disclosed in Patent Document 1, light is scattered by a scatterer, and thus the scattered light can intrude into the surrounding photoelectric conversion unit, leading to the possibility of mixing between different colors. Therefore, there is a possibility that the quality of the image obtained by the solid-state imaging device will degrade.

[0008] The purpose of this disclosure is to provide a solid-state imaging device and electronic device capable of reducing sensitivity differences between the same colors while suppressing color mixing between different colors.

[0009] Solutions to technical problems

[0010] The solid-state imaging apparatus disclosed herein includes: (a) a plurality of photoelectric conversion units formed on a substrate and generating signal charges according to the amount of incident light; (b) a microlens array including microlenses formed for a group of photoelectric conversion units including at least two adjacent photoelectric conversion units and guiding incident light to the group of photoelectric conversion units; (c) a scatterer arranged in the optical path of the incident light converged by the microlenses; and (d) an inter-pixel light-shielding portion including a groove and an insulating material filled in the groove, the groove being formed between the photoelectric conversion units of the group of photoelectric conversion units and the photoelectric conversion units adjacent to the group of photoelectric conversion units, wherein (e) the opening side of the inner surface of the groove on the scatterer side is a plane or a curved surface that is inclined in such a way that the groove width narrows toward the bottom of the groove.

[0011] Furthermore, the electronic device disclosed herein includes: (a) a solid-state imaging device, comprising: a plurality of photoelectric conversion units formed on a substrate and generating signal charges according to the amount of incident light; a microlens array, including microlenses formed for a group of photoelectric conversion units including at least two adjacent photoelectric conversion units and guiding incident light to the group of photoelectric conversion units; a scatterer arranged in the optical path of the incident light converged by the microlenses; and an inter-pixel light-shielding portion, including a groove and an insulating material filled in the groove, the groove being formed between the photoelectric conversion units of the group of photoelectric conversion units and the photoelectric conversion units adjacent to the group of photoelectric conversion units, the opening side of the inner surface of the groove on the scatterer side being a plane or a curved surface inclined in such a way that the groove width narrows toward the bottom of the groove; (b) an optical lens for forming image light from a subject on the imaging surface of the solid-state imaging device; and (c) a signal processing circuit for processing signals output from the solid-state imaging device. Attached Figure Description

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

[0013] Figure 2A The diagram illustrates the pixel area along... Figure 1 The diagram shows the cross-section constructed by the line AA in the diagram.

[0014] Figure 2B The diagram illustrates the pixel area along... Figure 2A The diagram shows the cross-section constructed by cutting line BB.

[0015] Figure 3A This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0016] Figure 3B This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0017] Figure 3C This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0018] Figure 3D This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0019] Figure 3E This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0020] Figure 3F This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0021] Figure 3G This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0022] Figure 3H This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0023] Figure 4 This is a cross-sectional view illustrating the structure of the pixel region of the solid-state imaging device according to the second embodiment.

[0024] Figure 5A This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0025] Figure 5B This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0026] Figure 5C This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0027] Figure 5D This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0028] Figure 5E This is an explanatory diagram illustrating the method of forming the light-blocking part between the scatterer and the pixel.

[0029] Figure 6A This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0030] Figure 6B The diagram illustrates the pixel area along... Figure 6A The cross-sectional view of the structure is obtained by cutting line CC in the middle.

[0031] Figure 7 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0032] Figure 8 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0033] Figure 9 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0034] Figure 10 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0035] Figure 11 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0036] Figure 12 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0037] Figure 13 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0038] Figure 14 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0039] Figure 15 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0040] Figure 16 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0041] Figure 17 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0042] Figure 18 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0043] Figure 19 This is a cross-sectional view illustrating the structure of the pixel region of a solid-state imaging device according to a variant example.

[0044] Figure 20 This is a diagram illustrating an example of the schematic construction of an electronic device.

[0045] Figure 21 This is a block diagram illustrating an example of a schematic construction of a vehicle control system.

[0046] Figure 22 This is an explanatory diagram showing an example of the installation location of the vehicle exterior information detection unit and the imaging unit.

[0047] Figure 23 This is a diagram illustrating an example of a schematic construction of an endoscopic surgical system.

[0048] Figure 24 This is a block diagram illustrating an example of the functional structure of the camera head and CCU. Detailed Implementation

[0049] In the following text, reference will be made to Figures 1 to 24Examples of a solid-state imaging apparatus 1 and an electronic device according to embodiments of the present disclosure are described below. Embodiments of the present disclosure will be described in the following order. However, it should be noted that the present disclosure is not limited to the following examples. Furthermore, the effects described in this specification are exemplary and not limiting, and may provide other effects.

[0050] 1. First embodiment: Solid-state imaging device

[0051] 1-1 Overall Structure of Solid State Imaging Device

[0052] Construction of the main parts 1-2

[0053] Methods for forming 1-3 scatterers and inter-pixel light-blocking parts

[0054] 2. Second embodiment: Solid-state imaging device

[0055] 2-1 Construction of the main parts

[0056] 2-2 Method for forming scatterers and light-blocking parts between pixels

[0057] 2-3 Variation Examples

[0058] 3. Examples of applications in electronic devices

[0059] 4. Examples of application to moving bodies

[0060] 5. Examples of applications in endoscopic surgical systems

[0061] <1. First Embodiment: Solid-State Imaging Device>

[0062] [1-1 Overall Structure of Solid-State Imaging Device]

[0063] A solid-state imaging apparatus 1 according to a first embodiment of the present disclosure will be described. Figure 1 This is a schematic structural diagram illustrating the overall structure of a solid-state imaging apparatus 1 according to a first embodiment of the present disclosure.

[0064] Figure 1 The solid-state imaging device 1 in the image is a back-illuminated CMOS (complementary metal-oxide-semiconductor) image sensor. For example... Figure 20 As shown, the solid-state imaging device 1 (101) receives image light (incident light 106) from the subject through an optical lens 102, converts the amount of light of the incident light 106 that is imaged on the imaging surface into an electrical signal in units of pixels, and outputs the electrical signal as a pixel signal.

[0065] like Figure 1 As shown, the solid-state imaging device 1 according to the first embodiment includes a substrate 2, a pixel region 3, a vertical driving circuit 4, a column signal processing circuit 5, a horizontal driving circuit 6, an output circuit 7, and a control circuit 8.

[0066] Pixel region 3 includes a plurality of pixels 9 arranged regularly on substrate 2 in a two-dimensional array. Pixel 9 includes, for example... Figure 2A and Figure 2B The photoelectric conversion unit 21 shown includes multiple pixel transistors (not shown). For example, four transistors—a transmission transistor, a reset transistor, a selection transistor, and an amplifier transistor—can be used as the multiple pixel transistors. Alternatively, three transistors other than the selection transistor can also be used.

[0067] The vertical driving circuit 4, for example, is composed of a shift register. It selects the desired pixel driving wiring 10, supplies pulses for driving the pixel 9 to the selected pixel driving wiring 10, and drives the pixel 9 row by row. That is, the vertical driving circuit 4 selectively scans the pixels 9 in the pixel region 3 row by row in the vertical direction, and supplies the pixel signal based on the signal charge generated according to the amount of light received in the photoelectric conversion unit 21 of each pixel 9 to the column signal processing circuit 5 through the vertical signal line 11.

[0068] The column signal processing circuit 5 is arranged for each column of pixels 9, and performs signal processing such as noise removal on the signal output from the pixel 9 corresponding to each row for each pixel column. For example, the column signal processing circuit 5 performs signal processing such as CDS (correlated double sampling) and AD (analog-to-digital) conversion to remove pixel-specific fixed-pattern noise.

[0069] The horizontal drive circuit 6 is, for example, composed of a shift register, which sequentially outputs horizontal scanning pulses to the column signal processing circuit 5 to sequentially select each column signal processing circuit 5, and outputs the processed pixel signal from each column signal processing circuit 5 to the horizontal signal line 12.

[0070] Output circuit 7 processes the pixel signals sequentially supplied from each column signal processing circuit 5 via horizontal signal lines 12 and outputs the pixel signals. Examples of signal processing that can be used include buffering, black level adjustment, column change correction, and various digital signal processing techniques.

[0071] The control circuit 8 generates a clock signal or control signal based on the vertical synchronization signal, the horizontal synchronization signal, and the master clock signal. This clock signal or control signal serves as a reference for the operation of the vertical drive circuit 4, the column signal processing circuit 5, and the horizontal drive circuit 6. Furthermore, the control circuit 8 outputs the generated clock signal or control signal to the vertical drive circuit 4, the column signal processing circuit 5, and the horizontal drive circuit 6.

[0072] [Construction of the main parts 1-2]

[0073] Next, the explanation will be... Figure 1The detailed structure of the solid-state imaging device 1 in the paper. Figure 2A This is a diagram illustrating the cross-sectional structure of the pixel region 3 of the solid-state imaging device 1. Figure 2B The illustration shows substrate 2 along... Figure 2A The diagram shows the plane constructed by the line BB in the middle. Figure 2A and Figure 2B In this study, a back-illuminated CMOS image sensor (CMOS solid-state imaging device) is used as a solid-state imaging device 1.

[0074] like Figure 2A and Figure 2B As shown, the solid-state imaging apparatus 1 according to the first embodiment includes a light-receiving layer 15, wherein a substrate 2, an insulating film 13, and a light-shielding film 14 are sequentially stacked. Furthermore, a light-concentrating layer 18 is formed on the surface of the light-receiving layer 15 on the side of the insulating film 13 (hereinafter also referred to as "back surface S1"), and a color filter 16 and a microlens 17 (on-chip lens, wafer lens) are sequentially stacked in the light-concentrating layer 18. Furthermore, a wiring layer 19 and a support substrate 20 are sequentially stacked on the surface of the light-receiving layer 15 on the side of the substrate 2 (hereinafter also referred to as "surface S2"). Meanwhile, the back surface S1 of the light-receiving layer 15 and the back surface of the insulating film 13 are the same surface; therefore, the back surface of the insulating film 13 will also be referred to as "back surface S1" in the following description. Furthermore, the surface S2 of the light-receiving layer 15 and the surface of the substrate 2 are the same surface; therefore, the surface of the substrate 2 will also be referred to as "surface S2" in the following description.

[0075] Substrate 2 is made of, for example, a semiconductor substrate formed of silicon (Si), and forms Figure 1 Pixel region 3 is shown. (As shown in the image) Figure 2A and Figure 2B As shown, multiple photoelectric conversion units 21 formed on the substrate 2 are arranged in a two-dimensional array in the pixel region 3, that is, multiple pixels 9 are constructed to include multiple photoelectric conversion units 21 embedded in the substrate 2. In the photoelectric conversion unit 21, a signal charge corresponding to the amount of incident light 24 is generated, and the generated signal charge is accumulated.

[0076] Regarding the photoelectric conversion unit 21, at least two adjacent photoelectric conversion units 21 constitute a photoelectric conversion unit group 23. In the first embodiment, the photoelectric conversion unit group 23 consists of four photoelectric conversion units 21 arranged in 2 rows and 2 columns. Multiple photoelectric conversion unit groups 23 are constructed using all the photoelectric conversion units 21. In this way, the photoelectric conversion unit groups 23 are arranged in a two-dimensional array.

[0077] A scatterer 25, which scatters the incident light 24, is formed between the photoelectric conversion units 21 constituting the photoelectric conversion unit group 23, that is, it is formed in the optical path of the incident light 24 converged by the microlens 17. By scattering the incident light 24 through the scatterer 25, the scattered incident light 24 can be distributed to the four photoelectric conversion units 21 adjacent to the scatterer 25. Therefore, the difference in light receiving sensitivity (the difference in sensitivity between the same color) between the four photoelectric conversion units 21 caused by pupil correction, etc., can be suppressed.

[0078] The scatterer 25 is configured to include a scatterer trench 26 and a scatterer insulating material 27. The scatterer trench 26 is formed along the depth direction from the surface of the substrate 2 on the side of the insulating film 13 (hereinafter also referred to as "back side S3"), and the scatterer insulating material 27 fills the scatterer trench 26. Figure 2B As shown, the scatterer trench 26 is formed in a lattice shape to physically isolate the photoelectric conversion units 21 constituting the photoelectric conversion unit group 23. The two inner sides of the scatterer trench 26 are planes formed extending along the depth direction from the back surface S3 side (light-receiving surface side) of the substrate 2 with a constant trench width. That is, the scatterer trench 26 has a straight line shape extending linearly in the depth direction of the substrate 2. By adopting a straight line shape, the reduction in the volume of the photoelectric conversion unit 21 adjacent to the scatterer 25 can be suppressed, and the reduction in the number of saturated electrons in the photoelectric conversion unit 21 can be suppressed. The same insulating material as the insulating material constituting the insulating film 13 is used as the scatterer insulating material 27.

[0079] The scattering of incident light 24 by the scatterer 25 occurs at the intersection of the interface between the scatterer 25 and the photoelectric conversion unit 21 and the back surface S3 of the substrate 2. Therefore, for incident light... Figure 2A Regarding the scattered light 28 on the inter-pixel light-shielding portion 29 shown, the closer the scattered light 28 is to the back surface S3 (light receiving surface) of the substrate 2, the smaller the incident angle of the scattered light 28 onto the inter-pixel light-shielding portion 29. Therefore, at a certain depth (hereinafter also referred to as the "critical depth") from the back surface S3 of the substrate 2, if the "incident angle θ of the scattered light 28 relative to the inter-pixel light-shielding portion 29" = the "critical angle (the minimum incident angle at which total internal reflection occurs when light is incident from the photoelectric conversion unit 21 onto the inter-pixel light-shielding portion 29)," then at a position shallower than the critical depth, the "incident angle θ of the scattered light 28 on the inter-pixel light-shielding portion 29" < the "critical angle," and the scattered light 28 will not undergo total internal reflection at the interface with the inter-pixel light-shielding portion 29. On the other hand, at a position deeper than the critical depth, the incident angle θ of the scattered light 28 on the inter-pixel shading part 29 is greater than the critical angle, and the scattered light 28 will undergo total internal reflection at the interface with the inter-pixel shading part 29.

[0080] Inter-pixel light-shielding portions 29 are formed between photoelectric conversion unit groups 23 (in other words, between photoelectric conversion units 21 formed in a photoelectric conversion unit group 23 and photoelectric conversion units 21 adjacent to that photoelectric conversion unit group 23). The inter-pixel light-shielding portions 29 are configured to include trenches 30 and insulating material 31. The trenches 30 are formed from the back surface S3 side (light-receiving surface side) of the substrate 2 along the depth direction, and the insulating material 31 fills the trenches 30. Figure 2B As shown, the trench 30 is formed in a lattice shape to physically isolate the photoelectric conversion unit groups 23. The opening sides of the two inner surfaces of the trench 30 (in other words, the opening side of the inner surface of the trench 30 on the side of the scatterer 25 and the opening side of the inner surface opposite to this inner surface) are planes that are inclined in such a way that the trench width narrows towards the bottom of the trench 30. That is, the opening side of the trench 30 has a tapered shape in which the trench width narrows towards the bottom of the trench 30. By adopting a tapered shape, the incident angle θ of the scattered light 28 relative to the inter-pixel light-blocking portion 29 can be increased, the critical depth can be reduced, and the region where the incident angle θ of the scattered light 28 at the interface between the inter-pixel light-blocking portion 29 and the photoelectric conversion unit 21 is greater than the critical angle can be expanded. Therefore, the scattered light 28 can be suppressed from entering the inter-pixel light-blocking portion 29, the scattered light 28 can be suppressed from entering the surrounding photoelectric conversion units 21, and the mixing between different colors can be reduced. As a result, the quality of the image obtained by the solid-state imaging device 1 can be improved.

[0081] At this time, the tilt angle of the planes on the opening sides of the two inner surfaces constituting the trench 30 relative to the thickness direction of the substrate 2 is preferably equal to or greater than the critical angle (the minimum angle of incidence at which total internal reflection occurs when light is incident from the photoelectric conversion unit 21 onto the inter-pixel light-shielding portion 29). For example, when the photoelectric conversion unit 21 is made of silicon (Si) and the insulating material 31 of the inter-pixel light-shielding portion 29 is made of silicon oxide (SiO2), the critical angle is 20.5°. Therefore, the tilt angle is preferably 20.5° or more. By setting the tilt angle of the planes to 20.5° or more, the scattered light 28 entering the inter-pixel light-shielding portion 29 can be more reliably subjected to total internal reflection on the opening side of the trench 30.

[0082] If the inter-pixel light-shielding portion 29 has a conical shape (i.e., a shape where the groove width narrows towards the bottom of the groove 30), the opening area of ​​the photoelectric conversion unit 21 becomes narrower, and the sensitivity of the photoelectric conversion unit 21 decreases. However, when the photoelectric conversion unit group 23 is composed of four photoelectric conversion units 21 arranged in 2 rows and 2 columns, the amount of light incident near the inter-pixel light-shielding portion 29 is already relatively small because the position of the scatterer 25 is the focal point. Therefore, the decrease in sensitivity of the photoelectric conversion unit 21 will be relatively small.

[0083] When the opening area of ​​the photoelectric conversion unit 21 becomes narrower, the amount of charge that can accumulate near the opening of the photoelectric conversion unit 21 decreases. However, since the signal charge generated near the opening is relatively small, the impact of the decrease in the amount of charge that can accumulate near the opening is relatively small.

[0084] The bottom sides of the two inner surfaces of the trench 30 (in other words, the bottom surface of the inner surface of the trench 30 on the scatterer 25 side and the bottom surface of the inner surface opposite to it) are planes formed extending from the back surface S3 side (light receiving surface side) of the substrate 2 along the depth direction with a constant trench width. That is, the bottom side of the trench 30 has a straight line shape extending linearly in the depth direction of the substrate 2. In this way, the trench 30 has a two-part structure with a conical shape and a straight line shape. By adopting a straight line shape, the reduction in the volume of the photoelectric conversion unit 21 adjacent to the inter-pixel light-shielding part 29 can be suppressed, and the reduction in the number of saturated electrons in the photoelectric conversion unit 21 can be suppressed.

[0085] When the groove 30 has a straight shape, the incident angle θ of the scattered light 28 on the inter-pixel light-shielding portion 29 is reduced compared to the case of a conical shape. However, since the incident angle θ of the scattered light 28 is larger in the straight portion, i.e., at the bottom side of the groove 30, by designing the boundary between the conical and straight shapes such that (incident angle θ) ≥ (critical angle), it is possible to suppress the scattered light 28 from entering the inter-pixel light-shielding portion 29, suppress the scattered light 28 from entering the surrounding photoelectric conversion unit 21, and reduce color mixing between different colors. As a result, it is possible to suppress the quality degradation of the image obtained by the solid-state imaging device 1.

[0086] The insulating material 31 used as the light-shielding part 29 between pixels is the same insulating material used to form the insulating film 13 and the scatterer insulating material 27.

[0087] The insulating film 13 continuously covers the entire back side S3 side (the entire light-receiving surface side) of the substrate 2. In addition, the light-shielding film 14 is formed in a grid pattern in a portion of the back side S1 side (the portion of the light-receiving surface side) of the insulating film 13, with each of the multiple photoelectric conversion unit groups 23 having an opening in its light-receiving surface.

[0088] Color filters 16 are formed on the back side S1 (light-receiving surface side) of the insulating film 13, corresponding to each photoelectric conversion unit group 23. That is, one color filter 16 is formed for each photoelectric conversion unit group 23. Therefore, the color filters 16 form a color filter array 32 regularly arranged in a two-dimensional array. Each color filter 16 is configured to allow a specific wavelength of incident light 24, such as red, green, or blue, which is desired to be received by the photoelectric conversion unit group 23, to pass through, and to allow the transmitted incident light 24 to be incident on the photoelectric conversion unit 21.

[0089] Microlenses 17 are formed on the back side S4 (light-receiving surface side) of the color filter 16, corresponding to each photoelectric conversion unit group 23. That is, one microlens 17 is formed for one of the photoelectric conversion unit groups 23. In this way, the microlenses 17 form a microlens array 33 arranged regularly in a two-dimensional array. Each microlens 17 is configured to converge the image light (incident light 24) from the subject and guide the converged incident light 24 through the color filter 16 to the vicinity of the back side (light-receiving surface) of the diffuser 25.

[0090] In this way, when a microlens 17 is shared by at least two adjacent photoelectric conversion units 21 (photoelectric conversion unit group 23), there are differences in the signal charges generated by the photoelectric conversion units 21 included in the same photoelectric conversion unit group 23. Therefore, in the solid-state imaging device 1, the distance to the subject can be calculated based on the differences in signal charges.

[0091] A wiring layer 19 is formed on the surface S2 side of the substrate 2 and is configured to include an interlayer insulating film 34 and wiring 35 stacked in multiple layers with the interlayer insulating film 34 in between. The wiring layer 19 drives the pixel transistors constituting the pixel 9 through the multilayer wiring 35.

[0092] A support substrate 20 is formed on the side of the wiring layer 19 opposite to the side facing the substrate 2. The support substrate 20 is a substrate used to ensure the strength of the substrate 2 during the manufacturing stage of the solid-state imaging device 1. For example, silicon (Si) can be used as the material of the support substrate 20.

[0093] In the solid-state imaging device 1 with the above-described structure, light is irradiated from the back side of the substrate 2 (the back side S1 side of the light-receiving layer 15). The irradiated light passes through the microlens 17 and the color filter 16, and the transmitted light is photoelectrically converted by the photoelectric conversion unit 21 to generate signal charge. Furthermore, the generated signal charge is transmitted as a pixel signal via the pixel transistor formed on the surface S2 side of the substrate 2 through the wiring 35. Figure 1 The vertical signal line 11 shown is output.

[0094] Furthermore, the distance to the subject can be calculated based on the difference in signal charges generated by each of the photoelectric conversion units 21 included in the same photoelectric conversion unit group 23.

[0095] [1-3 Methods for forming scatterers and light-blocking parts between pixels]

[0096] Next, the method for forming the scatterer 25 and the inter-pixel light-shielding part 29 in the solid-state imaging device 1 of the first embodiment will be described.

[0097] First, such as Figure 3A As shown, a hard mask layer 50 and a resist layer 51 are sequentially formed on the back surface S3 of the substrate 2 having the photoelectric conversion unit 21. Subsequently, as... Figure 3B As shown, the photoresist layer 51 is exposed and developed to form a mask 51a with lattice-shaped openings at the locations where the scatterer trenches 26 will be formed. Subsequently, as... Figure 3C As shown, the hard mask layer 50 is etched using the formed mask 51a to form the hard mask 50a. In this way, the pattern shape of the hard mask 50a becomes identical to the pattern shape of the mask 51a. Subsequently, as... Figure 3D As shown, after removing mask 51a from hard mask 50a, dry etching is performed using hard mask 50a to form scatterer trench 26 on substrate 2.

[0098] Subsequently, as Figure 3E As shown, a hard mask 52a with a grid-like opening at the location where the trench 30 will be formed is formed through the same process as described above. The width of the opening is the same as the width of the bottom side of the trench 30. Subsequently, as... Figure 3F As shown, dry etching is performed using a hard mask 52a to form trenches 30 on the substrate 2. In this way, straight trenches 30 are formed. Subsequently, as... Figure 3G As shown, wet etching is performed using a hard mask 52a to form the tapered inner surface of the trench 30 on the opening side. In this way, a trench 30 with a two-section structure having both a tapered and a straight shape is obtained. Subsequently, as... Figure 3H As shown, after removing the hard mask 52a from the substrate 2, the scatterer trench 26 is filled with scatterer insulating material 27 and the trench 30 is filled with insulating material 31 using a chemical vapor deposition (CVD) method or the like. In this way, a substrate 2 with scatterer 25 and inter-pixel light-shielding portion 29 formed is obtained.

[0099] As described above, the solid-state imaging device 1 of the first embodiment includes: a plurality of photoelectric conversion units 21 formed on a substrate 2 and generating signal charges according to the amount of incident light 24; a microlens array 33 including microlenses 17, the microlenses 17 being formed for a photoelectric conversion unit group 23 including at least two or more adjacent photoelectric conversion units 21 and guiding the incident light 24 to the photoelectric conversion unit group 23; a scatterer 25 arranged in the optical path of the incident light 24 converged by the microlenses 17; and an inter-pixel light-shielding portion 29 including a trench 30 and an insulating material 31 filled in the trench 30, the trench 30 being formed between the photoelectric conversion units 21 of the photoelectric conversion unit group 23 and the photoelectric conversion units 21 adjacent to the photoelectric conversion unit group 23. The opening side of the inner surface of the trench 30 on the scatterer 25 side is a plane inclined in such a way that the trench width narrows toward the bottom of the trench 30. In this manner, since the scatterer 25 is positioned in the optical path of the incident light 24, the incident light 24 can be scattered by the scatterer 25, and the difference in signal charge (sensitivity difference between the same color) generated by the photoelectric conversion unit 21 included in the same photoelectric conversion unit group 23 can be reduced. Since the opening side of the inner surface of the trench 30 on the scatterer 25 side is inclined, the incident angle of the scattered light 28 on the inter-pixel light-shielding part 29 can be increased on the opening side of the trench 30, the area where the scattered light 28 is totally reflected can be expanded, and color mixing between different colors can be suppressed. Therefore, a solid-state imaging device 1 that can reduce the sensitivity difference between the same color while suppressing color mixing between different colors can be provided.

[0100] In the solid-state imaging apparatus 1 of the first embodiment, the bottom side of the inner surface of the trench 30 on the scatterer 25 side has a plane that extends along the depth direction from the light-receiving surface side of the substrate 2 with a constant trench width. Therefore, the reduction in the volume of the photoelectric conversion unit 21 adjacent to the inter-pixel light-shielding portion 29 can be suppressed, and the reduction in the number of saturated electrons in the photoelectric conversion unit 21 can be suppressed.

[0101] In the solid-state imaging device 1 of the first embodiment, the scatterer 25 is configured to include a scatterer trench 26 and a scatterer insulating material 27. The scatterer trench 26 is formed between the photoelectric conversion units 21 in the photoelectric conversion unit group 23, and the scatterer insulating material 27 fills the scatterer trench 26. The two inner sides of the scatterer trench 26 are planes formed extending from the light-receiving surface side of the substrate 2 along the depth direction with a constant trench width. Therefore, the reduction in the volume of the photoelectric conversion unit 21 adjacent to the scatterer 25 can be suppressed, and the reduction in the number of saturated electrons in the photoelectric conversion unit 21 can be suppressed.

[0102] In the solid-state imaging apparatus 1 of the first embodiment, the opening side of the inner surface of the trench 30 on the scatterer 25 side is a plane inclined at an angle equal to or greater than the critical angle relative to the thickness direction of the substrate 2. The critical angle is the minimum incident angle at which total internal reflection occurs when light from the photoelectric conversion unit 21 is incident on the inter-pixel light-shielding part 29. Therefore, on the opening side of the trench 30, the incident angle of the scattered light 28 relative to the inter-pixel light-shielding part 29 can be set to be equal to or greater than the critical angle, enabling total internal reflection of the scattered light 28 and more reliably suppressing color mixing between different colors.

[0103] In the solid-state imaging apparatus 1 of the first embodiment, the insulating material 31 is silicon oxide. Furthermore, the critical angle is 20.5°. Here, the minimum incident angle at which total internal reflection occurs when light is incident from silicon onto the silicon oxide film is 20.5°. Therefore, at the opening side of the trench 30, total internal reflection of the scattered light 28 entering the inter-pixel light-shielding portion 29 can be performed more reliably.

[0104] <2. Second Embodiment: Solid-State Imaging Device>

[0105] [2-1 Construction of the main parts]

[0106] Next, the solid-state imaging apparatus 1 according to the second embodiment of this disclosure will be described. Since the overall structure of the solid-state imaging apparatus according to the second embodiment is similar to... Figure 1 The same as in [the previous text], therefore the illustration is omitted. Figure 4 This is a diagram illustrating the cross-sectional structure of the solid-state imaging device 1 according to the second embodiment. Figure 4 In, with Figure 2A and Figure 2B The corresponding parts in the figures are given the same reference numerals, and repeated descriptions will be omitted.

[0107] In the solid-state imaging device 1 according to the second embodiment, the structure of the scatterer 25 differs from the structure of the scatterer 25 in the solid-state imaging device 1 according to the first embodiment. In the second embodiment, as... Figure 4 As shown, the shape of the scatterer trench 26 of the scatterer 25 is the same as the shape of the trench 30 of the inter-pixel light-shielding portion 29. That is, the opening sides of the two inner surfaces of the scatterer trench 26 are planes that slope towards the bottom of the scatterer trench 26 with the trench width narrowing. The bottom sides of the two inner surfaces of the scatterer trench 26 are planes that extend along the depth direction from the back surface S3 side (light-receiving surface side) of the substrate 2 with a constant trench width. That is, similar to the trench 30, the scatterer trench 26 has a two-section structure with a conical shape and a straight shape.

[0108] [2-2 Method for forming scatterers and light-blocking parts between pixels]

[0109] Next, the method for forming the scatterer 25 and the inter-pixel light-shielding part 29 in the solid-state imaging device 1 of the second embodiment will be described.

[0110] First, such as Figure 3A As shown, similar to the method for forming the scatterer 25 and the inter-pixel light-shielding portion 29 in the first embodiment, a hard mask layer 50 and a resist layer 51 are sequentially formed on the back surface S3 of the substrate 2. Subsequently, as... Figure 5A As shown, the resist layer 51 is exposed and developed to form a mask 51a with grid-like openings at the locations where the scatterer trenches 26 and 30 will be formed. The width of the openings at the locations where the trenches 30 will be formed is the same as the width of the bottom side of the trenches 30. Subsequently, as... Figure 5B As shown, the hard mask layer 50 is etched using the formed mask 51a to form the hard mask 50a. In this way, the pattern shape of the hard mask 50a becomes identical to the pattern shape of the mask 51a. Subsequently, as... Figure 5C As shown, after removing mask 51a from the formed hard mask 50a, dry etching is performed using hard mask 50a to form scatterer trenches 26 and trenches 30 on substrate 2. In this way, straight scatterer trenches 26 and trenches 30 are formed.

[0111] Subsequently, as Figure 5D As shown, wet etching is performed using a hard mask 50a to form the conical inner surfaces of the scatterer trenches 26 and 30 on the opening side. In this way, scatterer trenches 26 and 30 with a two-segment structure having both a conical and a straight shape are obtained. Subsequently, as... Figure 5E As shown, after removing the hard mask 50a from the substrate 2, the scatterer trench 26 is filled with scatterer insulating material 27 and the trench 30 is filled with insulating material 31 by using a CVD method or the like. In this way, a substrate 2 with scatterer 25 and inter-pixel light-shielding portion 29 formed is obtained.

[0112] As described above, in the solid-state imaging apparatus 1 of the second embodiment, since the scatterer groove 26 of the scatterer 25 has the same shape as the groove 30 of the inter-pixel light-shielding portion 29, the scatterer 25 and the inter-pixel light-shielding portion 29 can be formed in the same process, and the scatterer 25 and the inter-pixel light-shielding portion 29 can be formed easily.

[0113] If the opening side of the scatterer trench 26 has a tapered shape (i.e., the trench width narrows towards the bottom of the scatterer trench 26), the opening area of ​​the photoelectric conversion unit 21 becomes narrower, and the amount of charge that can accumulate near the opening of the photoelectric conversion unit 21 is reduced. However, since the signal charge generated near the opening is relatively small, the effect of the reduction in the amount of charge that can accumulate near the opening is relatively small.

[0114] [2-3 Variation Examples]

[0115] (1) In the solid-state imaging apparatus 1 according to the first and second embodiments, an example is illustrated where the photoelectric conversion unit group 23 is composed of four photoelectric conversion units 21 in 2 rows and 2 columns, but other configurations are possible. For example, such as Figure 6A and Figure 6B As shown, the photoelectric conversion unit group 23 can be composed of two photoelectric conversion units 21 arranged in 2 rows and 1 column. Only a portion of all photoelectric conversion units 21 are used to form the photoelectric conversion unit group 23. In the photoelectric conversion units 21 that do not constitute the photoelectric conversion unit group 23, a microlens 17 is formed for each photoelectric conversion unit 21.

[0116] (2) In the solid-state imaging apparatus 1 according to the first embodiment, an example is illustrated where each of the opening sides of the two inner surfaces of the groove 30 is a plane that slopes towards the bottom of the groove 30 in such a way that the groove width narrows. However, other configurations are possible. For example, such as Figure 7 As shown, each of the two inner opening sides of the groove 30 can be a multi-segment plane that is inclined in such a way that the groove width narrows toward the bottom of the groove 30. Figure 7 The illustration shows a case where the opening side of the inner surface of the groove 30 consists of two planar segments. For example, as shown... Figure 8 As shown, the opening sides of the two inner surfaces of the groove 30 can be curved surfaces that narrow towards the bottom of the groove 30. For example, as Figure 9 As shown, the two inner sides of the groove 30 can be planes that are inclined in such a way that the groove width narrows toward the bottom of the groove 30.

[0117] The same construction can be adopted for the solid-state imaging device 1 according to the second embodiment. For example, as Figure 10 As shown, each of the two inner side openings of the groove 30 of the inter-pixel light-shielding part 29 can be a multi-segment plane that is inclined in such a way that the groove width narrows toward the bottom of the groove 30, and each of the two inner side openings of the scatterer groove 26 of the scatterer 25 can be a multi-segment plane that is inclined in such a way that the groove width narrows toward the bottom of the scatterer groove 26. Figure 10 The illustration shows the case where the opening side of the inner surface of trench 30 and scatterer trench 26 is two planar segments. For example, as... Figure 11 As shown, the opening sides of the two inner surfaces of the groove 30 of the inter-pixel light-shielding portion 29 can be curved surfaces that are curved in a manner where the groove width narrows towards the bottom of the groove 30, and the opening sides of the two inner surfaces of the scatterer groove 26 of the scatterer 25 can be curved surfaces that are curved in a manner where the groove width narrows towards the bottom of the scatterer groove 26. For example, as Figure 12As shown, the two inner sides of the groove 30 of the inter-pixel light-shielding portion 29 can be planes that are inclined in a manner where the groove width narrows towards the bottom of the groove 30, and the two inner sides of the scatterer groove 26 of the scatterer 25 can be planes that are inclined in a manner where the groove width narrows towards the bottom of the scatterer groove 26. When the inner sides of the groove 30, etc., are curved surfaces, the opening side of the inner side of the scatterer 25 side of the groove 30 can be a curved surface such that the angle of this curved surface relative to the thickness direction of the substrate 2 decreases towards the bottom of the groove 30. By doing so, the incident angle θ of the scattered light 28 near the back surface S3 of the substrate 2 (near the light receiving surface) can be increased, the area where the scattered light 28 is totally reflected can be expanded, and color mixing between different colors can be suppressed.

[0118] (3) In the solid-state imaging apparatus 1 according to the first and second embodiments, an example is illustrated where the insulating material 31 of the inter-pixel light-shielding portion 29 is the same insulating material as the scatterer insulating material 27 of the scatterer 25, but other structures can be adopted. For example, such as Figure 13 and Figure 14 As shown, the insulating material 31 of the inter-pixel light-shielding portion 29 can be an insulating material with a refractive index lower than that of the scatterer insulating material 27 of the scatterer 25. Examples of low-refractive-index insulating materials include, for example, titanium nitride (TiN), magnesium fluoride (MgF2), lithium fluoride (LiF), calcium fluoride (CaF2), air, and low-refractive-index resins. Examples of low-refractive-index resins include resins with a refractive index lower than that of silicon oxide (SiO2) (n = 1.45). Figure 13 The illustration shows its application in a solid-state imaging apparatus 1 according to a first embodiment. Figure 14 The illustration shows its application in the solid-state imaging apparatus 1 according to the second embodiment. Compared to using a high-refractive-index insulating material, using a low-refractive-index insulating material can reduce the critical angle at which total internal reflection occurs when scattered light 28 is incident from the photoelectric conversion unit 21 onto the inter-pixel light-shielding portion 29, expand the area where scattered light 28 is totally reflected, and more reliably suppress color mixing between different colors.

[0119] For example, such as Figure 15 and Figure 16As shown, the scattering insulating material 27 of the scatterer 25 can be a high-refractive-index insulating material. As a high-refractive-index insulating material, an insulating material with a refractive index higher than that of silicon (Si) constituting the substrate 2 can be used. Examples include titanium oxide (TiO2), silicon nitride (SiN), zirconium oxide (ZrO2), hafnium oxide (HfO2), tantalum oxide (Ta2O3), zinc oxide (ZnO), and high-refractive-index resins. Examples of high-refractive-index resins include resins with a refractive index greater than that of silicon oxide (SiO2) (n = 1.45). Compared to using a low-refractive-index insulating material, using a high-refractive-index insulating material can reduce the intensity of the scattered light 28. Figure 15 The illustration shows its application in a solid-state imaging apparatus 1 according to a first embodiment. Figure 16 The illustration shows its application in a solid-state imaging apparatus 1 according to the second embodiment. Therefore, the intensity of scattered light 28 incident on the inter-pixel light-shielding portion 29 can be reduced, and color mixing between different colors can be reduced more reliably.

[0120] For example, such as Figure 17 and Figure 18 As shown, the insulating material 31 of the inter-pixel light-shielding part 29 can be an insulating material with a refractive index lower than that of the scatterer insulating material 27 of the scatterer 25, and the scatterer insulating material 27 of the scatterer 25 can be an insulating material with a high refractive index. Figure 17 The illustration shows its application in a solid-state imaging apparatus 1 according to a first embodiment. Figure 18 The illustration shows its application in a solid-state imaging apparatus 1 according to a second embodiment.

[0121] (4) In the solid-state imaging apparatus 1 according to the first embodiment, an example is illustrated in which a scatterer 25 is formed between the photoelectric conversion units 21 constituting the photoelectric conversion unit group 23, but other configurations can be used. For example, such as Figure 19 As shown, an intermediate layer 36 can be formed between the color filter 16 and the substrate 2, and an oblate spheroidal scatterer 25 can be formed in the optical path of the incident light 24 converged by the microlens 17 in the intermediate layer 36. When the oblate spheroidal scatterer 25 is provided, an impurity layer 37 formed by injecting impurities into the substrate 2 is formed between the photoelectric conversion units 21 constituting the photoelectric conversion unit group 23. As impurities, for example, phosphorus, arsenic, and boron can be used.

[0122] <3. Examples of applications in electronic devices>

[0123] The technology disclosed herein (the technology) can be applied to various electronic devices, such as imaging devices like digital cameras and digital video cameras, mobile phones with imaging capabilities, or other devices with imaging capabilities.

[0124] Figure 20 This is a diagram illustrating an example of a schematic construction of an electronic device (e.g., a camera) capable of applying the technology (the present technology) according to this disclosure.

[0125] like Figure 20 As shown, 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.

[0126] Optical lens 102 forms an image of the image light (incident light 106) from the subject onto the imaging surface of solid-state imaging device 101. Therefore, signal charge accumulates in solid-state imaging device 101 over a certain period. Shutter device 103 controls the illumination period and shading period of solid-state imaging device 101. Drive circuit 104 supplies drive signals for controlling the transmission operation of solid-state imaging device 101 and the shutter operation of shutter device 103. The operation of transmitting signals to solid-state imaging device 101 is performed using the drive signals (timing signals) supplied from drive circuit 104. Signal processing circuit 105 performs various signal processing on the signals (pixel signals) output from solid-state imaging device 101. The processed video signal is stored in a storage medium such as a memory or output to a monitor.

[0127] Note that the electronic device 100 to which the solid-state imaging device 1 can be applied is not limited to a camera; the solid-state imaging device 1 can also be applied to other electronic devices. The solid-state imaging device 1 can be applied to imaging devices such as camera modules of mobile devices such as mobile phones or tablet terminals.

[0128] Examples of electronic devices to which the technology according to this disclosure can be applied have been described above. The technology according to this disclosure can be applied to the solid-state imaging device 101 within the above-described configuration. Specifically, Figure 1 The solid-state imaging device 1 can be applied to the solid-state imaging device 101. When the technology according to this disclosure is applied to the solid-state imaging device 101, better captured images can be obtained.

[0129] <4. Examples of application to moving bodies>

[0130] The technology disclosed herein (the Technology) can be implemented as a device mounted on any type of mobile body, such as a car, electric car, hybrid car, motorcycle, bicycle, personal mobile device, airplane, drone, ship, and robot.

[0131] Figure 21 This is a block diagram illustrating a schematic construction example of a vehicle control system, which is an example of a mobile body control system capable of applying the technology according to this disclosure.

[0132] The vehicle control system 12000 includes multiple electronic control units connected via a communication network 12001. Figure 21 In the example shown, the vehicle control system 12000 includes a drive system control unit 12010, a vehicle body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and a comprehensive control unit 12050. Furthermore, as part of the functional structure of the comprehensive control unit 12050, a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown.

[0133] The drive system control unit 12010 controls the operation of devices related to the vehicle drive system according to various programs. For example, the drive system control unit 12010 functions as a control device for the following devices: a drive force generating device for generating the driving force of the vehicle, such as an internal combustion engine or drive motor; a drive force transmission mechanism for transmitting the driving force to the wheels; a steering mechanism for adjusting the steering angle of the vehicle; and a braking device for generating the braking force of the vehicle.

[0134] The vehicle system control unit 12020 controls the operation of various devices installed in the vehicle body according to various programs. For example, the vehicle system control unit 12020 functions as a control device for keyless entry systems, smart key systems, power windows, or various lights such as headlights, taillights, brake lights, turn signals, and fog lights. In this case, radio waves transmitted from a portable device that replaces the key, or signals from various switches, can be input to the vehicle system control unit 12020. The vehicle system control unit 12020 receives such radio wave or signal input and controls the vehicle's door locks, power windows, and lights.

[0135] The exterior information detection unit 12030 detects external information of the vehicle on which the vehicle control system 12000 is installed. For example, the imaging unit 12031 is connected to the exterior information detection unit 12030. The exterior information detection unit 12030 causes the imaging unit 12031 to capture images of the exterior of the vehicle and receives the captured images. The exterior information detection unit 12030 can perform object detection processing or distance detection processing for people, vehicles, obstacles, signs, and road markings based on the received images.

[0136] Imaging unit 12031 is a light sensor that receives light and outputs an electrical signal corresponding to the amount of light received. Imaging unit 12031 can also output the electrical signal as an image and ranging information. Furthermore, the light received by imaging unit 12031 can be visible light or invisible light such as infrared light.

[0137] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 for detecting the driver's state is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that images the driver, and the in-vehicle information detection unit 12040 can calculate the driver's fatigue level or concentration level based on the detection information input from the driver state detection unit 12041, and can determine whether the driver is dozing off.

[0138] The microcomputer 12051 can calculate the control target values ​​for the drive force generating device, steering mechanism, or braking device based on external or internal information obtained by the external information detection unit 12030 or the internal information detection unit 12040, and can output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control for the purpose of realizing the functions of an advanced driver assistance system (ADAS), such as following the vehicle based on collision avoidance, impact mitigation, and distance control, maintaining vehicle speed, collision warning, and lane departure warning.

[0139] Furthermore, by controlling the drive force generating device, steering mechanism, or braking device based on information about the vehicle's surroundings obtained by the external information detection unit 12030 or the internal information detection unit 12040, the microcomputer 12051 is capable of cooperative control aimed at autonomous driving, in which the driver does not rely on his or her operation.

[0140] Furthermore, the microcomputer 12051 can output control commands to the vehicle system control unit 12020 based on external information obtained by the external information detection unit 12030. For example, the microcomputer 12051 can perform cooperative control for the purpose of glare reduction, such as controlling the headlights to switch from high beams to low beams based on the position of the preceding or oncoming vehicle detected by the external information detection unit 12030.

[0141] The audio-visual output unit 12052 transmits at least one of the audio and visual signals to an output device capable of visually or audibly notifying vehicle occupants or the outside of the vehicle. Figure 21 In the example shown, an audio speaker 12061, a display unit 12062, and a dashboard 12063 are illustrated as such output devices. The display unit 12062 may include, for example, at least one of an in-vehicle display and a head-up display.

[0142] Figure 22 This is a diagram showing an example of the mounting location of the imaging unit 12031.

[0143] exist Figure 22In the vehicle 12100, imaging units 12101, 12102, 12103, 12104 and 12105 are included as imaging units 12031.

[0144] Imaging units 12101, 12102, 12103, 12104, and 12105 can be positioned, for example, at locations such as the front nose, side mirrors, rear bumper, rear door, and upper part of the interior windshield of vehicle 12100. Imaging unit 12101 at the front nose and imaging unit 12105 at the upper part of the interior windshield primarily acquire images of the front of vehicle 12100. Imaging units 12102 and 12103 at the side mirrors primarily acquire images of the sides of vehicle 12100. Imaging unit 12104 at the rear bumper or rear door primarily acquires images of the rear of vehicle 12100. The front images acquired by imaging units 12101 and 12105 are mainly used to detect vehicles ahead, pedestrians, obstacles, traffic lights, traffic signs, and lanes.

[0145] here, Figure 22 An example of the imaging range of imaging units 12101 to 12104 is shown. Imaging range 12111 represents the imaging range of imaging unit 12101 located at the front nose, imaging ranges 12112 and 12113 represent the imaging ranges of imaging units 12102 and 12103 located at the side mirrors, respectively, and imaging range 12114 represents the imaging range of imaging unit 12104 located at the rear bumper or rear door. For example, by superimposing the image data captured by imaging units 12101 to 12104, a bird's-eye view of the vehicle 12100 viewed from above can be obtained.

[0146] At least one of the imaging units 12101 to 12104 may have the function of obtaining distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera including multiple imaging elements, or may be an imaging element having pixels for phase difference detection.

[0147] For example, the microcomputer 12051 determines the distances between itself and each three-dimensional object within the imaging range 12111 to 12114, and how these distances change over time (relative to the vehicle 12100), based on distance information obtained from imaging units 12101 to 12104. Specifically, it can extract a three-dimensional object that is the closest three-dimensional object on the vehicle 12100's travel path and is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., above 0 km / h). Furthermore, the microcomputer 12051 can pre-set the required distance between itself and the preceding vehicle and can perform automatic braking control (including stop-and-go control) and automatic acceleration control (including start-and-go control). In this way, cooperative control can be performed for the purpose of autonomous driving, where the driver does not need to operate the vehicle.

[0148] For example, based on distance information obtained from imaging units 12101 to 12104, microcomputer 12051 classifies 3D object data related to 3D objects into 3D object data for two-wheeled vehicles, standard-sized vehicles, large vehicles, pedestrians, utility poles, or other 3D objects, extracts the classified 3D object data, and can use the extracted 3D object data to automatically avoid obstacles. For example, microcomputer 12051 distinguishes obstacles around vehicle 12100 into obstacles that the driver of vehicle 12100 can visually recognize and obstacles that the driver cannot visually recognize. Then, microcomputer 12051 determines the collision risk, which represents the degree of danger of colliding with each obstacle, and when the collision risk is equal to or higher than a set value and there is a possibility of collision, it outputs a warning to the driver through audio speaker 12061 and display unit 12062, and performs forced deceleration and evasive steering through drive system control unit 12010. Therefore, assisted driving for collision avoidance can be performed.

[0149] At least one of the imaging units 12101 to 12104 can be an infrared camera that detects infrared light. For example, the microcomputer 12051 can identify a pedestrian by determining whether a pedestrian exists in the images captured by the imaging units 12101 to 12104. This pedestrian identification is performed, for example, by: extracting feature points from the images captured by the imaging units 12101 to 12104, which are infrared cameras; and performing pattern matching processing on a series of feature points representing the outline of an object and determining whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian exists in the images captured by the imaging units 12101 to 12104 and identifies the pedestrian, the sound image output unit 12052 controls the display unit 12062 to display and overlay a square outline used for emphasis along with the identified pedestrian. Furthermore, the sound image output unit 12052 can control the display unit 12062 to display an icon or similar symbol representing a pedestrian at a desired location.

[0150] Examples of vehicle control systems that can be applied according to the technology of this disclosure have been described above. The technology of this disclosure can be applied to the imaging unit 12031 within the above-described configuration. Specifically, Figure 1 The solid-state imaging device 1 can be applied to the imaging unit 12031. By applying the technology according to this disclosure to the imaging unit 12031, flare can be suppressed and clearer images can be obtained, thereby reducing driver fatigue.

[0151] <5. Examples of applications in endoscopic surgical systems>

[0152] The technology disclosed herein (the technology) can be applied, for example, to endoscopic surgical systems.

[0153] Figure 23 This is a diagram illustrating an example of a schematic construction of an endoscopic surgical system capable of applying the technology (the present technology) according to this disclosure.

[0154] Figure 23 The illustration depicts a surgeon (physician) 11131 performing surgery on a patient 11132 on bed 11133 using an endoscopic surgical system 11000. As shown, the endoscopic surgical system 11000 includes: an endoscope 11100; other surgical instruments 11110 such as a pneumoperitoneum tube 11111 and an energy therapy device 11112; a support arm device 11120 supporting the endoscope 11100; and a trolley 11200 in which various devices used in endoscopic surgery are mounted.

[0155] Endoscope 11100 includes a tube 11101 and a camera head 11102. A predetermined length of the tube 11101 is inserted into the body cavity of a patient 11132. The camera head 11102 is connected to the base of the tube 11101. In the illustrated example, an endoscope 11100 is shown as a so-called rigid endoscope with a rigid tube 11101; however, endoscope 11100 can be configured as a so-called flexible endoscope with a flexible tube.

[0156] An opening is provided at the end of the endoscope tube 11101, and the objective lens is installed in this opening. A light source device 11203 is connected to the endoscope 11100. Light generated by the light source device 11203 is guided to the end of the endoscope tube 11101 via a light guide extending inside the tube, and the light is then directed through the objective lens toward the target to be observed in the body cavity of the patient 11132. Here, the endoscope 11100 can be a direct-viewing endoscope, or an oblique-viewing endoscope, or a lateral-viewing endoscope.

[0157] An optical system and an imaging element are housed inside the camera head 11102. Reflected light from the observed target (observation light) is converged onto the imaging element by the optical system. The imaging element performs photoelectric conversion on the observation light, generating an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is transmitted as RAW data to the camera control unit (CCU) 11201.

[0158] The CCU 11201 includes a central processing unit (CPU) or a graphics processing unit (GPU), and integrates the operation of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives image signals from the camera head 11102 and performs various types of image processing on the image signals, such as developing (de-mosaicing), for displaying images based on the image signals.

[0159] Under the control of CCU 11201, display device 11202 displays an image based on an image signal that has been image processed by CCU 11201.

[0160] For example, the light source device 11203 includes a light source such as a light-emitting diode (LED) and supplies illumination light to the endoscope 11100 when imaging the surgical site.

[0161] Input device 11204 is the input interface of endoscopic surgery system 11000. Users can input various types of information and commands into endoscopic surgery system 11000 via input device 11204. For example, users can input commands to change the imaging conditions of endoscope 11100 (type of illumination light, magnification, focal length, etc.).

[0162] Treatment tool control device 11205 controls the drive of energy therapy tool 11112 used for tissue cauterization, cutting, or vascular closure. To ensure the field of vision of endoscope 11100 and to ensure the surgeon's working space, pneumoperitoneum device 11206 delivers gas into the body cavity of patient 11132 via pneumoperitoneum tube 11111 to inflate the body cavity. Recorder 11207 is a device capable of recording various types of information related to the surgery. Printer 11208 is a device capable of printing various types of information related to the surgery in various formats such as text, images, and graphics.

[0163] Here, the light source device 11203 that supplies illumination light for imaging the surgical site to the endoscope 11100 can include, for example, an LED, a laser light source, or a white light source composed of combinations thereof. When the white light source includes a combination of RGB laser light sources, the white balance of the captured image can be adjusted in the light source device 11203 because the output intensity and timing of various colors (various wavelengths) can be controlled with high precision. Furthermore, in this case, by irradiating the target with lasers from each of the RGB laser light sources in a time-division manner and controlling the driving of the imaging element of the camera head 11102 in sync with the irradiation timing, images corresponding to RGB can be captured in a time-division manner. According to this method, color images can be obtained even without providing a color filter in the imaging element.

[0164] Furthermore, the drive of the light source device 11203 can be controlled so that the intensity of the output light changes at predetermined intervals. When the drive of the imaging element of the camera head 11102 is controlled in sync with the change in light intensity, images are acquired and synthesized in a time-division manner, resulting in so-called high dynamic range images without underexposure or overexposure.

[0165] Furthermore, the light source device 11203 can be configured to supply light of a predetermined wavelength corresponding to specific light observation. In specific light observation, for example, so-called narrow-band light observation (narrow-band imaging) is performed by irradiating a narrower wavelength band than the irradiation light (i.e., white light) used during conventional observation, utilizing the wavelength dependence of light absorption by human tissue. This allows for high-contrast imaging of predetermined tissues such as blood vessels in the mucosal surface. Alternatively, fluorescence observation can be performed in specific light observation, where an image is obtained by irradiating fluorescence generated by excitation light. Fluorescence observation (autofluorescence observation) can be performed by irradiating excitation light onto human tissue and observing fluorescence from the tissue, or by locally injecting a reagent such as indocyanine green (ICG) into human tissue and irradiating the tissue with excitation light corresponding to the fluorescence wavelength of the reagent to obtain a fluorescence image. The light source device 11203 can supply narrow-band light and / or excitation light corresponding to these specific light observations.

[0166] Figure 24 It's a diagram. Figure 23 A block diagram illustrating an example of the functional configuration of the camera head 11102 and CCU 11201.

[0167] The camera head 11102 includes a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 to enable them to communicate with each other.

[0168] Lens unit 11401 is an optical system disposed at the connection point with lens barrel 11101. Observation light entering from the end of lens barrel 11101 is guided to camera head 11102 and then enters lens unit 11401. Lens unit 11401 includes a combination of multiple lenses, including zoom lenses and focusing lenses.

[0169] Imaging unit 11402 includes imaging elements. The imaging elements constituting imaging unit 11402 can be a single element (so-called single-plate type) or multiple elements (so-called multi-plate type). When imaging unit 11402 is, for example, composed of a multi-plate type, the imaging elements generate image signals respectively corresponding to RGB, and these image signals are synthesized to obtain a color image. Alternatively, imaging unit 11402 may include a pair of imaging elements for acquiring right-eye and left-eye image signals corresponding to three-dimensional (3D) display. When performing 3D display, surgeon 11131 can more accurately determine the depth of biological tissue at the surgical site. Here, when imaging unit 11402 is composed of a multi-plate type, multiple lens units 11401 can be provided according to each imaging element.

[0170] Furthermore, the imaging unit 11402 is not necessarily located in the camera head 11102. For example, the imaging unit 11402 may be located inside the lens barrel 11101 immediately after the objective lens.

[0171] The drive unit 11403 includes an actuator, and under control from the camera head control unit 11405, the drive unit 11403 moves the zoom lens and focusing lens of the lens unit 11401 a predetermined distance along the optical axis. Therefore, the magnification and focus of the image captured by the imaging unit 11402 can be appropriately adjusted.

[0172] Communication unit 11404 includes communication means for transmitting / receiving various information to / from CCU 11201. Communication unit 11404 transmits image signals obtained from imaging unit 11402 as RAW data to CCU 11201 via transmission cable 11400.

[0173] Furthermore, the communication unit 11404 receives control signals from the CCU 11201 for controlling the driving of the camera head 11102, and supplies the control signals to the camera head control unit 11405. The control signals include information related to imaging conditions, such as information for specifying the frame rate of the captured image, information for specifying the exposure value during imaging, and / or information for specifying the magnification and focus of the captured image.

[0174] Here, imaging conditions such as frame rate, exposure value, magnification, and focus can be appropriately specified by the user, or can be automatically set by the control unit 11413 of CCU 11201 based on the acquired image signal. In the latter case, the so-called AE (automatic exposure), AF (automatic focus), and AWB (automatic white balance) functions are set in endoscope 11100.

[0175] The camera head control unit 11405 controls the drive of the camera head 11102 based on control signals received from the CCU 11201 via the communication unit 11404.

[0176] The communication unit 11411 includes a communication device for transmitting / receiving various types of information to / from the camera head 11102. The communication unit 11411 receives image signals transmitted from the camera head 11102 via a transmission cable 11400.

[0177] Furthermore, the communication unit 11411 transmits control signals for controlling the driving of the camera head 11102 to the camera head 11102. Image signals and control signals can be transmitted via electrical communication or optical communication.

[0178] The image processing unit 11412 performs various types of image processing on the image signal, which is RAW data transmitted from the camera head 11102.

[0179] The control unit 11413 performs various controls related to imaging the surgical site by the endoscope 11100, and performs various controls related to displaying the captured images obtained by imaging the surgical site. For example, the control unit 11413 generates control signals for controlling the drive of the camera head 11102.

[0180] Furthermore, the control unit 11413 causes the display device 11202 to display a captured image of the surgical site, etc., based on the image signal processed by the image processing unit 11412. In this case, the control unit 11413 can use various image recognition technologies to identify various objects in the captured image. For example, the control unit 11413 can identify surgical instruments such as forceps, specific biological sites, bleeding, and mist generated when using the energy therapy tool 11112 by detecting the edge shape and color of objects included in the captured image. When the control unit 11413 causes the display device 11202 to display the captured image, the control unit 11413 can use the recognition results to overlay various types of surgical support information with the image of the surgical site. When the surgical support information is overlaid and presented to the surgeon 11131, the workload of the surgeon 11131 can be reduced, and the surgeon 11131 can perform the surgery reliably.

[0181] The transmission cable 11400 that connects the camera head 11102 and CCU 11201 to each other is an electrical signal cable that supports electrical signal communication, an optical fiber that supports optical communication, or a composite cable of both.

[0182] Here, in the example shown in the attached figure, although communication is conducted in a wired manner using transmission cable 11400, communication between camera head 11102 and CCU 11201 can also be conducted wirelessly.

[0183] Examples of endoscopic surgical systems that can utilize the technology according to this disclosure have been described above. The technology according to this disclosure can be applied to the imaging unit 11402 within the aforementioned configuration. Specifically, Figure 1 The solid-state imaging device 1 can be applied to the imaging unit 11402. By applying the technology according to this disclosure to the imaging unit 11402, clearer images of the surgical site can be obtained, thus enabling surgeons to reliably identify the surgical site.

[0184] Although an endoscopic surgical system has been described as an example herein, the techniques according to this disclosure can also be applied to other systems, such as microscopic surgical systems.

[0185] Note that this technique can also be constructed using the following method.

[0186] (1) A solid-state imaging device comprising: a plurality of photoelectric conversion units formed on a substrate and generating signal charges according to the amount of incident light; a microlens array comprising microlenses formed for a group of photoelectric conversion units including at least two adjacent photoelectric conversion units and guiding incident light to the group of photoelectric conversion units; a scatterer disposed in the optical path of the incident light converged by the microlenses; and an inter-pixel light-shielding portion comprising a trench and an insulating material filled in the trench, the trench being formed between the photoelectric conversion units of the group of photoelectric conversion units and the photoelectric conversion units adjacent to the group of photoelectric conversion units, wherein the opening side of the inner surface of the trench on the scatterer side is a plane or a curved surface that is inclined such that the trench width narrows toward the bottom of the trench.

[0187] (2) The solid-state imaging device according to (1), wherein the bottom side of the inner surface of the scatterer side of the trench is a plane formed by extending from the light receiving surface side of the substrate along the depth direction in a manner in which the width of the trench is constant.

[0188] (3) The solid-state imaging device according to (1) or (2), wherein the scatterer includes a scatterer groove and a scatterer insulating material filled in the scatterer groove, the scatterer groove is formed between the photoelectric conversion units in the photoelectric conversion unit group, and the two inner sides of the scatterer groove are planes formed by extending from the light receiving surface side of the substrate along the depth direction in a manner with a constant groove width.

[0189] (4) The solid-state imaging device according to (1) or (2), wherein the scatterer includes a scatterer groove and a scatterer insulating material filled in the scatterer groove, the scatterer groove is formed between the photoelectric conversion units in the photoelectric conversion unit group, and the scatterer groove has the same shape as the groove.

[0190] (5) The solid-state imaging device according to (1) or (2), wherein the scatterer is arranged between the microlens and the substrate, and an impurity layer is formed between the photoelectric conversion units in the photoelectric conversion unit group.

[0191] (6) The solid-state imaging device according to (3) or (4), wherein the refractive index of the insulating material in the trench is lower than the refractive index of the scatterer insulating material.

[0192] (7) The solid-state imaging device according to any one of (3), (4) and (6), wherein the scatterer insulating material is any one of titanium oxide, silicon nitride, zirconium oxide, hafnium oxide, tantalum oxide, zinc oxide and a high refractive index resin with a refractive index higher than that of silicon oxide.

[0193] (8) The solid-state imaging apparatus according to any one of (1) to (7), wherein the opening side of the inner surface of the scatterer side of the trench is a plane inclined at an angle equal to or greater than the critical angle relative to the thickness direction of the substrate, the critical angle being the minimum incident angle at which total internal reflection occurs when light is incident from the photoelectric conversion unit onto the inter-pixel light-shielding portion.

[0194] (9) The solid-state imaging device according to (8), wherein the insulating material is silicon oxide and the critical angle is 20.5°.

[0195] (10) The solid-state imaging apparatus according to any one of (1) to (7), wherein the opening side of the inner surface of the scatterer side of the trench is a curved surface that decreases in angle with respect to the thickness direction of the substrate toward the bottom of the trench.

[0196] (11) An electronic device comprising a solid-state imaging device, an optical lens, and a signal processing circuit, the solid-state imaging device comprising: a plurality of photoelectric conversion units formed on a substrate and generating signal charges according to the amount of incident light; a microlens array comprising microlenses formed for a group of photoelectric conversion units including at least two adjacent photoelectric conversion units and guiding incident light to the group of photoelectric conversion units; a scatterer disposed in the optical path of the incident light converged by the microlenses; and an inter-pixel light-shielding portion comprising a trench and an insulating material filled in the trench, the trench being formed between the photoelectric conversion units of the group of photoelectric conversion units and the photoelectric conversion units adjacent to the group of photoelectric conversion units, the opening side of the inner surface of the trench on the scatterer side being a plane or a curved surface inclined such that the trench width narrows toward the bottom of the trench, the optical lens forming image light from a subject on the imaging surface of the solid-state imaging device, and the signal processing circuit processing a signal output from the solid-state imaging device.

[0197] List of reference numerals

[0198] 1 Solid-state imaging device

[0199] 2 substrate

[0200] 3-pixel area

[0201] 4 Vertical drive circuit

[0202] 5-column signal processing circuits

[0203] 6. Horizontal drive circuit

[0204] 7 Output Circuit

[0205] 8. Control Circuit

[0206] 9 pixels

[0207] 10-pixel driving wiring

[0208] 11 Vertical signal line

[0209] 12 Horizontal Signal Lines

[0210] 13 Insulating film

[0211] 14 shading film

[0212] 15. Optical Receiving Layer

[0213] 16 Color Filters

[0214] 17 Microlenses

[0215] 18 Concentrating Layers

[0216] 19 Wiring Layer

[0217] 20 Supporting substrate

[0218] 21 Photoelectric conversion unit

[0219] 23 Photoelectric conversion unit group

[0220] 24 Incident light

[0221] 25 Scatterers

[0222] 26 Scatterer trenches

[0223] 27. Scattering Insulating Materials

[0224] 28 Scattered light

[0225] 29-pixel light-blocking section

[0226] 30 trenches

[0227] 31 Insulation Materials

[0228] 32-color filter array

[0229] 33 microlens array

[0230] 34-layer interlayer insulating film

[0231] 35. Wiring

[0232] 36 Intermediate Layer

[0233] 37 Impurity Layer

[0234] 100 electronic devices

[0235] 101 Solid-State Imaging Device

[0236] 102 Optical Lenses

[0237] 103 Shutter mechanism

[0238] 104 drive circuit

[0239] 105 Signal Processing Circuit

[0240] 106 Incident light

Claims

1. A solid-state imaging device, comprising: Multiple photoelectric conversion units are formed on a substrate and generate signal charges according to the amount of incident light; A microlens array, the microlens array comprising microlenses formed for a group of photoelectric conversion units comprising at least two adjacent photoelectric conversion units and guiding incident light to the group of photoelectric conversion units; A scatterer, the scatterer being arranged in the optical path of the incident light converged by the microlens; and An inter-pixel light-shielding portion includes a trench and an insulating material filling the trench. The trench is formed between a photoelectric conversion unit in the photoelectric conversion unit group and a photoelectric conversion unit adjacent to the photoelectric conversion unit group. The opening side of the inner surface of the trench on the scatterer side is a plane or a curved surface that is inclined in such a way that the trench width narrows towards the bottom of the trench, wherein The bottom side of the inner surface of the scatterer side of the trench is a plane that extends along the depth direction from the light-receiving surface side of the substrate in a manner where the trench width is constant.

2. The solid-state imaging device according to claim 1, wherein... The scatterer includes scatterer trenches and scatterer insulating material filling the scatterer trenches, the scatterer trenches being formed between the photoelectric conversion units in the photoelectric conversion unit group, and The two inner sides of the scatterer trench are planes formed by extending from the light-receiving surface of the substrate along the depth direction with a constant trench width.

3. The solid-state imaging device according to claim 1, wherein... The scatterer includes scatterer trenches and scatterer insulating material filling the scatterer trenches, the scatterer trenches being formed between the photoelectric conversion units in the photoelectric conversion unit group, and The scatterer trench has the same shape as the trench.

4. The solid-state imaging device according to claim 1, wherein... The scatterer is disposed between the microlens and the substrate, and An impurity layer is formed between the photoelectric conversion units in the photoelectric conversion unit group.

5. The solid-state imaging device according to claim 2, wherein... The refractive index of the insulating material in the trench is lower than that of the scatterer insulating material.

6. The solid-state imaging device according to claim 2, wherein... The scatterer insulating material is any one of titanium oxide, silicon nitride, zirconium oxide, hafnium oxide, tantalum oxide, zinc oxide, and a high refractive index resin with a refractive index higher than that of silicon oxide.

7. The solid-state imaging apparatus according to any one of claims 1 to 6, wherein The opening side of the inner surface of the scatterer side of the trench is a plane inclined at an angle equal to or greater than the critical angle relative to the thickness direction of the substrate. The critical angle is the minimum incident angle at which total internal reflection occurs when light is incident from the photoelectric conversion unit onto the light-shielding part between pixels.

8. The solid-state imaging device according to claim 7, wherein The insulating material is silicon dioxide, and The critical angle is 20.5°.

9. The solid-state imaging apparatus according to any one of claims 1 to 6, wherein The opening side of the inner surface of the scatterer side of the trench is a curved surface that decreases in size towards the bottom of the trench at an angle to the thickness direction of the substrate.

10. An electronic device comprising: Solid-state imaging apparatus as described in any one of claims 1 to 9; An optical lens, which forms image light from the subject onto the imaging surface of the solid-state imaging device; and A signal processing circuit that processes the signal output from the solid-state imaging device.

Images