Solid-state imaging device, manufacturing method, and electronic device

Abstract

The present disclosure relates to a solid-state imaging element, a manufacturing method, and an electronic device which make further improvements in performance possible. This solid-state imaging element comprises: a semiconductor substrate to which photoelectric conversion units are provided for each pixel; and a filter layer which is provided to the light-receiving surface side of the semiconductor substrate. In the filter layer, filters shaped such that the surface shape thereof is formed into a protruding shape are provided for each pixel, and an inter-pixel light-shielding section composed of a low-refractive-index material, which has a lower refractive index than the filters, is provided between the pixels. The filters are formed by being applied to a base material provided in a pattern smaller than the pixel pitch so as to protrude with respect to an insulation film formed on the surface of the semiconductor substrate, whereby the surface shape of the filters is formed into a protruding shape. The present art can be applied to CMOS image sensors, for example.

Description

[Technical Field]

[0001] The present disclosure relates to a solid-state imaging device, a manufacturing method, and an electronic device, and more particularly to a solid-state imaging device, a manufacturing method, and an electronic device that are capable of achieving further performance improvement. [Background technology]

[0002] Conventionally, solid-state imaging devices such as CMOS (Complementary Metal Oxide Semiconductor) image sensors have adopted a structure in which an on-chip lens is provided for each pixel in order to improve light collection efficiency.

[0003] However, structures that use lenses to focus light can only focus light up to the diffraction limit (approximately the wavelength), and the light spreads due to diffraction after focusing. Therefore, as the focusing point of an on-chip lens moves closer to the front as pixels become smaller, there is a concern that in micro-pixels whose size is close to the wavelength of the light being focused, the light spreads due to diffraction after focusing, making them more susceptible to color mixing than in large pixels. Therefore, as measures to suppress this type of color mixing, structures that make the on-chip lens as low in height as possible or structures that do not have an on-chip lens have been proposed.

[0004] For example, Patent Document 1 proposes an imaging element that employs a structure without an on-chip lens, provides partitions between pixels made of a transparent material with a lower refractive index than the color filters, and forms the partitions in a tapered shape on the light incident side to suppress color mixing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-156463 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a structure without an on-chip lens as disclosed in the above-mentioned Patent Document 1, light passes through a partition (made of a transparent material with a low refractive index) provided between pixels, which can increase color mixing and reduce quantum efficiency QE. Therefore, there is a demand for improving the performance of image sensors by reducing the occurrence of color mixing and increasing quantum efficiency QE.

[0007] The present disclosure has been made in view of such circumstances, and aims to enable further improvement in performance. [Means for solving the problem]

[0008] A solid-state imaging device according to one aspect of the present disclosure includes a semiconductor substrate on which a photoelectric conversion unit is provided for each pixel, and a filter layer provided on a light-receiving surface side of the semiconductor substrate, the filter layer including a filter having a curved surface. and a base material for controlling the surface shape of the filter. is provided for each pixel, and an inter-pixel light-shielding portion made of a low refractive index material having a refractive index lower than that of the filter is provided between the pixels.

[0009] A manufacturing method according to one aspect of the present disclosure is a manufacturing method for a solid-state imaging device including a semiconductor substrate on which a photoelectric conversion unit is provided for each pixel, and a filter layer provided on a light-receiving surface side of the semiconductor substrate, the filter layer including a filter having a curved surface. and a base material for controlling the surface shape of the filter. and providing an inter-pixel light-shielding portion between the pixels, the inter-pixel light-shielding portion being made of a low refractive index material having a refractive index lower than that of the filter.

[0010] An electronic device according to one aspect of the present disclosure includes a semiconductor substrate on which a photoelectric conversion unit is provided for each pixel, and a filter layer provided on a light-receiving surface side of the semiconductor substrate, the filter layer including a filter having a curved surface. and a base material for controlling the surface shape of the filter. is provided for each pixel, and an inter-pixel light-shielding portion made of a low refractive index material having a refractive index lower than that of the filter is provided between the pixels.

[0011] In one aspect of the present disclosure, a filter layer having a curved surface is provided on a light-receiving surface side of a semiconductor substrate on which a photoelectric conversion unit is provided for each pixel. , and a base material for controlling the surface shape of the filter is provided for each pixel, and an inter-pixel light-shielding portion made of a low refractive index material having a refractive index lower than that of the filter is provided between the pixels. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating a configuration example of a first embodiment of an imaging element to which the present technology is applied. [Figure 2] 10 is a cross-sectional view showing an example of the configuration of an image sensor in which an on-chip lens is not provided and the surface shape of a color filter is flat. FIG. [Figure 3] FIG. 10 is a diagram illustrating reduction of color mixing. [Figure 4] FIG. 10 is a diagram illustrating an example of an application of the first filter structure. [Figure 5] FIG. 10 is a diagram illustrating an example of an application of the second filter structure. [Figure 6] FIG. 10 is a diagram illustrating an example of an application example of the third filter structure. [Figure 7] FIG. 10 is a diagram illustrating an example of an application of a fourth filter structure. [Figure 8] FIG. 10 is a diagram illustrating an example of an application example of the fifth filter structure. [Figure 9] FIG. 10 is a diagram illustrating an example of an application example of a sixth filter structure. [Figure 10] FIG. 10 is a diagram illustrating an example of an application example of a seventh filter structure. [Figure 11] FIG. 10 is a diagram illustrating an example of a modified image sensor. [Figure 12] 1A to 1C are diagrams illustrating a method for manufacturing an imaging element. [Figure 13] 1A to 1C are diagrams illustrating a method for manufacturing an imaging element. [Figure 14] FIG. 10 is a diagram illustrating a configuration example of a second embodiment of an imaging element to which the present technology is applied. [Figure 15]FIG. 10 is a diagram illustrating an example of application of a Bayer array filter structure. [Figure 16] 1A to 1C are diagrams illustrating a method for manufacturing an imaging element. [Figure 17] 1A to 1C are diagrams illustrating a method for manufacturing an imaging element. [Figure 18] FIG. 1 is a block diagram illustrating an example of the configuration of an imaging device. [Figure 19] FIG. 1 is a diagram illustrating an example of use of an image sensor. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, specific embodiments to which the present technology is applied will be described in detail with reference to the drawings.

[0014] <First Configuration Example of Image Sensor> FIG. 1 is a diagram showing a configuration example of a first embodiment of an imaging element to which the present technology is applied.

[0015] The image sensor 11 is configured with a plurality of pixels 12 arranged in an array, and Fig. 1 shows an example cross-sectional configuration of three pixels 12-1 to 12-3. For example, pixel 12-1 receives red light, pixel 12-2 receives green light, and pixel 12-3 receives blue light. Hereinafter, when there is no need to distinguish between the pixels 12-1 to 12-3, they will simply be referred to as pixel 12.

[0016] 1, the image sensor 11 is configured by laminating a filter layer 22 on the light-receiving surface side of a semiconductor substrate 21. An insulating film 23 is formed on the surface of the semiconductor substrate 21, and an anti-reflection film 24 is formed on the surface of the filter layer 22.

[0017] The semiconductor substrate 21 is, for example, a thinly sliced ​​single-crystal silicon wafer, and a photoelectric conversion unit (not shown) is provided for each pixel 12. The semiconductor substrate 21 also has an element isolation section 31 formed by filling with, for example, silicon dioxide (SiO2) to optically and electrically isolate adjacent pixels 12. Note that air may be used as the element isolation section 31, and a structure can be adopted in which the spaces between the pixels 12 in the semiconductor substrate 21 are hollow.

[0018] The filter layer 22 is configured by disposing a base material 41 and a filter 42 for each pixel 12, and by providing an inter-pixel light-shielding portion 43 between adjacent pixels 12.

[0019] The base material 41 has a pattern smaller than the pitch of the pixels 12, and is provided independently for each pixel 12 so as to be convex with respect to the insulating film 23 of the semiconductor substrate 21 at the center of the pixel 12. The base material 41 is used to control the surface shape of the filter 42, and the height of the base material 41 is formed to be equal to or less than the height of the inter-pixel light-shielding portion 43. The base material 41 is made of a material that has a refractive index equal to or less than that of the semiconductor substrate 21 (silicon) and a refractive index equal to or greater than that of the low-refractive-index material of the inter-pixel light-shielding portion 43, and is formed by depositing, for example, silicon dioxide (refractive index n=1.46 at a wavelength of 530 nm).

[0020] The filters 42 are laminated on the base material 41, and are made of resin containing pigments corresponding to the colors of light received by the pixels 12, and transmit light of the corresponding colors. For example, filter 42-1 transmits red light, filter 42-2 transmits green light, and filter 42-3 transmits blue light.

[0021] The inter-pixel light-shielding portion 43 is made of a low-refractive index material that has a lower refractive index than the filters 42, and suppresses light from entering between the pixels 12 in the filter layer 22. Note that air may be used as the inter-pixel light-shielding portion 43, and a structure in which the spaces between the filters 42 are hollow may be employed.

[0022] In the imaging element 11 configured in this manner, after the insulating film 23 is formed on the surface of the semiconductor substrate 21, an independent pattern of base material 41 is formed for each pixel 12 and a filter 42 is applied, so that the surface shape of the filter 42 is formed into a convex shape (a condenser lens shape). Therefore, in the imaging element 11, light irradiated onto the pixels 12 is condensed by the filter 42. This makes it possible to avoid a decrease in light condensing efficiency even in a configuration in which an on-chip lens is not provided.

[0023] Furthermore, the image sensor 11 does not have an on-chip lens, which allows structures provided above the semiconductor substrate 21 to be made low-profile. Therefore, even if the light-collecting point of the filter 42 moves toward the front as the pixels 12 become smaller, the image sensor 11 has a low-profile structure and can efficiently confine light within the pixels 12 using the inter-pixel light-shielding portion 43. This allows the image sensor 11 to reduce the occurrence of color mixing and increase quantum efficiency QE, thereby improving performance.

[0024] 2, in an image sensor 11a having a structure in which an on-chip lens is not provided and in which the surface shape of the filter 42a is formed flat, light passes through the inter-pixel light-shielding portion 43. That is, as indicated by the dashed-dotted arrow in Fig. 2, part of the light heading toward the inter-pixel light-shielding portion 43 passes through the inter-pixel light-shielding portion 43 and enters the semiconductor substrate 21. As a result, there are concerns that the occurrence of color mixing will increase and the quantum efficiency QE will decrease in the image sensor 11a.

[0025] 1, the surface shape of the filter 42 is formed in a convex shape, thereby preventing light from passing through the inter-pixel light-shielding portion 43. That is, as indicated by the dashed-dotted arrow in FIG. 1, light heading toward the inter-pixel light-shielding portion 43 is refracted at the surface of the filter 42, thereby preventing the light from entering the inter-pixel light-shielding portion 43. As a result, the image sensor 11 can reduce the occurrence of color mixing and increase the quantum efficiency QE.

[0026] FIG. 3 is a diagram illustrating the reduction of color mixing in the imaging element 11. In FIG.

[0027] As shown in FIG. 3, the quantum efficiency QE is compared between pixel 12-1, which receives red (R) light from an image sensor 11 having a filter 42 with a convex surface shape, and pixel 12a-1, which receives red (R) light from an image sensor 11a having a filter 42a with a flat surface shape.

[0028] For example, in the region surrounded by the circular two-dot chain line, that is, in the wavelength range of green light, the quantum efficiency QE of pixel 12-1 is shown to be lower than the quantum efficiency QE of pixel 12a-1. That is, in the image sensor 11a, green light is mixed into pixel 12a-1, which receives red (R) light, whereas in the image sensor 11, this mixing is suppressed.

[0029] In particular, in the image sensor 11a, there was a tendency for obliquely incident light to leak into adjacent pixels, increasing the occurrence of color mixing. In contrast, in the image sensor 11, the angle of incidence of obliquely incident light toward the inter-pixel light shielding portion 43 is shallower than in the image sensor 11a, and the light is totally reflected by the inter-pixel light shielding portion 43, thereby reducing the occurrence of color mixing even in a structure without an on-chip lens.

[0030] <Example of filter structure application> 4 to 10, application examples in which the structure of the image sensor 11 in Fig. 1 is applied to various filter structures will be described. Note that in the following application examples, components common to the image sensor 11 in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0031] Fig. 4 is a diagram showing an example of an application in which the structure of image sensor 11 in Fig. 1 is applied to a first filter structure. Fig. 4A shows a planar layout of image sensor 11A, and Fig. 4B shows an example of a cross-sectional configuration of two pixels 12A-1 and 12A-2 surrounded by dashed lines shown in Fig. 4A.

[0032] As shown in FIG. 4, in the imaging element 11A, the filter layer 22A, which is the first filter structure, has a pattern in which filters 42A are arranged in a 2×2 array of four pixels 12A, with red (R) in the upper left pixel 12A, green (G) in the upper right and lower left pixels 12A, and blue (B) in the lower right pixel 12A, and this 2×2 pixel 12A pattern is repeated (a so-called Bayer array).

[0033] In addition, in the imaging element 11A, as indicated by the two-dot chain line in A of FIG. 4, the base material 41A is formed independently for each pixel 12A in the center of each pixel 12A in a circular pattern smaller than the pixel pitch.

[0034] For example, in the imaging element 11A, a structure in which silicon dioxide is used as the base material 41A, air is used as the inter-pixel light-shielding portion 43, and silicon dioxide is used as the element isolation portion 31 can be employed.

[0035] Fig. 5 is a diagram showing an example of an application in which the structure of image sensor 11 in Fig. 1 is applied to a second filter structure. Fig. 5A shows a planar layout of image sensor 11B, and Fig. 5B shows an example of a cross-sectional configuration of two pixels 12B-1 and 12B-2 surrounded by dashed lines shown in Fig. 5A.

[0036] 5, in the image sensor 11B, a filter layer 22B having a second filter structure has transparent (W) filters 42B that transmit light in all wavelength ranges arranged for all pixels 12B. That is, the image sensor 11B to which the second filter structure is applied has a so-called monochrome structure in which luminance values ​​are output from all pixels 12B.

[0037] In addition, in the imaging element 11B, as indicated by the two-dot chain line in FIG. 5A, the base material 41B is formed independently for each pixel 12B in the center of each pixel 12B in a circular pattern smaller than the pixel pitch.

[0038] For example, in the imaging element 11B, a structure can be adopted in which silicon dioxide is used as the base material 41B, silicon nitride (SiN) is used for the transparent filter 42B, air is used as the inter-pixel light-shielding portion 43, and silicon dioxide is used as the element isolation portion 31.

[0039] Fig. 6 is a diagram showing an example of an application in which the structure of the image sensor 11 in Fig. 1 is applied to a third filter structure. Fig. 6A shows a planar layout of the image sensor 11C, and Fig. 6B shows an example of a cross-sectional configuration of four pixels 12C-1 to 12C-4 arranged in a row out of the eight pixels 12C surrounded by a dashed line shown in Fig. 6A.

[0040] As shown in Figure 6, in the imaging element 11C, the filter layer 22C, which is the third filter structure, has filters 42C arranged in a pattern where, for 16 4x4 pixels 12C, red (R) is placed in the upper left 2x2 pixels 12C, green (G) is placed in the upper right and lower left 2x2 pixels 12C, and blue (B) is placed in the lower right 2x2 pixels 12C, and this 4x4 pixel 12C pattern is repeated.

[0041] 6A, the base material 41C is formed in a circular pattern smaller than the pixel pitch at the center of each pixel 12C, independently for each pixel 12C. Therefore, the image sensor 11C is configured so that a filter 42C having a convex surface shape is provided for each pixel 12C, and light is collected for each pixel 12C.

[0042] For example, in the imaging element 11C, a structure in which silicon dioxide is used as the base material 41C, air is used as the inter-pixel light-shielding portion 43, and silicon dioxide is used as the element isolation portion 31 can be employed.

[0043] Fig. 7 is a diagram showing an example of an application in which the structure of the image sensor 11 in Fig. 1 is applied to a fourth filter structure. Fig. 7A shows a planar layout of the image sensor 11D, and Fig. 7B shows an example of a cross-sectional configuration of four pixels 12D-1 to 12D-4 arranged in a row out of the eight pixels 12D surrounded by a dashed line shown in Fig. 7A.

[0044] As shown in Figure 7, in the image sensor 11D, the filter layer 22D, which is the fourth filter structure, has filters 42D arranged in a pattern in which, for 16 4x4 pixels 12D, red (R) is placed in the upper left 2x2 pixels 12D, green (G) is placed in the upper right and lower left 2x2 pixels 12D, and blue (B) is placed in the lower right 2x2 pixels 12D, and this 4x4 pixel 12D pattern is repeated.

[0045] 7A, in the image sensor 11D, a base material 41D is formed in the center of an area consisting of four 2×2 pixels 12D of the same color, in a circular pattern smaller than the 2×2 pixel pitch, independently for each four pixels 12D. Therefore, the image sensor 11D is configured so that a filter 42D having a convex surface shape is provided for the four 2×2 pixels 12D, and light is collected for each of the four pixels 12D.

[0046] For example, in the imaging element 11D, a structure in which silicon dioxide is used as the base material 41D, air is used as the inter-pixel light-shielding portion 43, and silicon dioxide is used as the element isolation portion 31 can be employed.

[0047] Fig. 8 is a diagram showing an example of an application in which the structure of the image sensor 11 in Fig. 1 is applied to a fifth filter structure. Fig. 8A shows a planar layout of the image sensor 11E, and Fig. 8B shows an example of a cross-sectional configuration of four pixels 12E-1 to 12E-4 surrounded by dashed lines shown in Fig. 8A.

[0048] 8, image sensor 11E uses rectangular pixels 12E in which the length of one vertical side is twice the length of one horizontal side. Filter layer 22E, which is the fifth filter structure, has eight 4×2 pixels 12E, and filters 42E are arranged in a pattern in which red (R) is in the upper left 2×1 pixel 12E, green (G) is in the upper right and lower left 2×1 pixel 12E, and blue (B) is in the lower right 2×1 pixel 12E, and this 4×2 pixel 12E pattern is repeated.

[0049] 8A, in the image sensor 11E, a base material 41E is formed in the center of an area consisting of two 2×1 pixels 12E of the same color, in a circular pattern smaller than the pixel pitch of 2×1, independently for each pair of pixels 12D. Therefore, the image sensor 11E is configured so that a filter 42E having a convex surface shape is provided for each of the two 2×1 pixels 12E, and light is collected for each pair of pixels 12E.

[0050] For example, in the imaging element 11E, a structure in which silicon dioxide is used as the base material 41E, air is used as the inter-pixel light-shielding portion 43, and silicon dioxide is used as the element isolation portion 31 can be employed.

[0051] Fig. 9 is a diagram showing an example of an application in which the structure of the image sensor 11 in Fig. 1 is applied to a sixth filter structure. Fig. 9A shows a planar layout of the image sensor 11F, and Fig. 9B shows an example of a cross-sectional configuration of four pixels 12F-1 to 12F-4 surrounded by dashed lines shown in Fig. 9A.

[0052] 9, the image sensor 11F uses rectangular pixels 12F, each of which has a vertical side twice as long as a horizontal side. The filter layer 22F, which is the sixth filter structure, has 32 8×4 pixels 12F, and filters 42F are arranged in a pattern in which red (R) is in the upper left 4×2 pixels 12F, green (G) is in the upper right and lower left 4×2 pixels 12F, and blue (B) is in the lower right 4×2 pixels 12F, and this pattern of 8×4 pixels 12F is repeated.

[0053] 9A, in the image sensor 11F, a base material 41F is formed in the center of an area consisting of two 2×1 pixels 12F of the same color, in a circular pattern smaller than the pixel pitch of 2×1, independently for each pair of pixels 12F. Therefore, the image sensor 11F is configured so that a filter 42F having a convex surface shape is provided for each of the two 2×1 pixels 12F, and light is collected for each pair of pixels 12F.

[0054] For example, in the imaging element 11F, a structure in which silicon dioxide is used as the base material 41F, air is used as the inter-pixel light-shielding portion 43, and silicon dioxide is used as the element isolation portion 31 can be employed.

[0055] Fig. 10 is a diagram showing an example of an application in which the structure of the image sensor 11 in Fig. 1 is applied to a seventh filter structure. Fig. 10A shows a planar layout of the image sensor 11G, and Fig. 10B shows an example of a cross-sectional configuration of two pixels 12G-1 to 12G-4 surrounded by a dashed line shown in Fig. 10A.

[0056] As shown in Figure 10, in the imaging element 11G, the filter layer 22G, which is the seventh filter structure, has filters 42G arranged in a pattern where, for 16 4x4 pixels 12G, the upper left 2x2 pixels 12G are red (R), the upper right and lower left 2x2 pixels 12G are green (G), the upper left pixel 12G of the lower right 2x2 is green (G), and the remaining three pixels 12G are blue (B), and this 4x4 pixel 12G pattern is arranged regularly at predetermined intervals in the row and column directions, replacing part of the third filter structure shown in Figure 6 above.

[0057] 10A, the base material 41F is basically formed in an independent circular pattern for each pixel 12G, as shown by the two-dot chain line. However, for the 2×1 green (G) pixels 12G surrounded by the dashed line, a circular pattern is formed in the center of the area consisting of those two pixels 12G. For example, these two pixels 12G are used for phase difference detection for autofocus control. Therefore, in the image sensor 11G, light is collected by the two pixels 12G for the 2×1 green (G) pixels 12G used for phase difference detection.

[0058] <Modification of the imaging element> A modified example of the imaging element 11 will be described with reference to FIG.

[0059] In the image pickup device 11 of FIG. 1, the surface shape of the filter 42 is formed in a convex shape, whereas in the image pickup device 11H shown in FIG. 11, the surface shape of the filter 42H is formed in a concave shape.

[0060] That is, in the image sensor 11H, the base material 41H is provided around the pixels 12H in a pattern smaller than the pitch of the pixels 12H, with each pixel 12H being an independent circle with a recessed center. That is, the image sensor 11H is configured such that the periphery of the pixel 12H is convex due to the base material 41H, and the center of the pixel 12H is recessed by removing the base material 41H so that the insulating film 23 of the semiconductor substrate 21 is exposed.

[0061] In the image sensor 11H configured in this manner, after the insulating film 23 is formed on the surface of the semiconductor substrate 21, a film serving as a base material is formed on the entire surface, and the center of the film is removed for each pixel 12H to form the base material 41H, and the filter 42H is applied, thereby forming a concave surface shape for the filter 42H. Therefore, in the image sensor 11H, the light irradiated to the pixel 12H spreads as shown by the dashed-dotted arrow in B of Fig. 11, but is totally reflected by the inter-pixel light-shielding portion 43 and is confined within the pixel 12H.

[0062] For example, in the imaging element 11H, a structure in which silicon dioxide is used as the base material 41H, air is used as the inter-pixel light-shielding portion 43, and silicon dioxide is used as the element isolation portion 31 can be employed.

[0063] In this way, in addition to filter 42 having a convex surface shape, filter 42H having a concave surface shape may also be used, and a configuration having a curved surface shape can suppress color mixing more effectively than a configuration having a flat surface shape.

[0064] <Method of manufacturing an image sensor> A method for manufacturing the imaging element 11 will be described with reference to FIGS.

[0065] In the first step, as shown in the first row of FIG. 12, a semiconductor substrate 21 is prepared, on which an isolation portion 31 is provided between pixels 12 and an insulating film 23 is formed on the surface.

[0066] In the second step, as shown in the second row of FIG. 12, an underlying material 41 is formed on the insulating film 23 on the surface of the semiconductor substrate 21 in an independent pattern for each pixel 12.

[0067] 12, a low refractive index material 51 that will become the inter-pixel light-shielding portion 43 is applied to the entire surface. At this time, the low refractive index material 51 is formed so that the surface shape of each pixel 12 becomes a convex shape due to the influence of the base material 41.

[0068] In the fourth step, as shown in the first row of FIG. 13, the low refractive index material 51 is partially removed so as to remain only between the pixels 12, thereby forming the inter-pixel light-shielding portions 43.

[0069] 13, in the fifth step, a filter 42 of a color corresponding to each pixel 12 is formed by coating. At this time, the filter 42 is formed so that the surface shape of each pixel 12 becomes a convex shape due to the influence of the base material 41.

[0070] In a sixth step, as shown in the third row of FIG. 13, an anti-reflection film 24 is formed on the surface of the filter 42.

[0071] By the manufacturing method described above, it is possible to manufacture an imaging element 11 that has inter-pixel light-shielding portions 43 provided between pixels 12, has filters 42 with convex surfaces, and can reduce the occurrence of color mixing.

[0072] <Second Configuration Example of Image Sensor> FIG. 14 is a diagram showing a configuration example of a second embodiment of an imaging element to which the present technology is applied.

[0073] 14, the surface of a semiconductor substrate 21J (silicon having a refractive index n=4.15 at a wavelength of 530 nm) is processed by etching, for example, for each pixel 12J so that it has a convex shape. Therefore, in the image sensor 11J, a filter 42J is formed by coating on the semiconductor substrate 21J having such a surface shape, so that the surface of the filter 42J also has a convex shape.

[0074] That is, while the imaging element 11 in FIG. 1 is configured such that the surface shape of the filter 42 is convex by providing a base material 41 on the surface of the semiconductor substrate 21, the imaging element 11J is configured such that the surface shape of the filter 42J is convex by making the surface shape of the semiconductor substrate 21J convex.

[0075] In the image sensor 11J having such a configuration, similarly to the image sensor 11 of FIG. 1, by using a filter 42J having a convex surface shape to collect light for each pixel 12J, it is possible to reduce the occurrence of color mixing and increase the quantum efficiency QE.

[0076] Fig. 15 is a diagram showing an example of an application in which the structure of image sensor 11J in Fig. 14 is applied to a so-called Bayer array filter structure. Fig. 15A shows a planar layout of image sensor 11J, and Fig. 15B shows an example of a cross-sectional configuration of two pixels 12J-1 and 12J-2 surrounded by dashed lines shown in Fig. 15A.

[0077] The filter structure shown in Figure 15 is similar to Figure 4 in that, for four 2x2 pixels 12J, filters 42J are arranged in a pattern in which red (R) is in the upper left pixel 12J, green (G) is in the upper right and lower left pixels 12J, and blue (B) is in the lower right pixel 12J, and this 2x2 pixel 12J pattern is repeated (a so-called Bayer array).

[0078] For example, in the imaging element 11J, a structure in which air is used as the inter-pixel light shielding portion 43 and silicon dioxide is used as the element isolation portion 31 can be employed.

[0079] <Method of manufacturing an image sensor> A method for manufacturing the imaging element 11J will be described with reference to FIGS.

[0080] In an eleventh step, as shown in the first row of FIG. 16, a semiconductor substrate 21 in which element isolation portions 31 are provided between pixels 12 is prepared.

[0081] In a twelfth step, as shown in the second row of FIG. 16, the surface of the semiconductor substrate 21J is processed by, for example, etching so as to have a convex shape.

[0082] 16, in a thirteenth step, after forming an insulating film 23 on the surface of the semiconductor substrate 21J, a low refractive index material 51 that will become the inter-pixel light-shielding portion 43 is applied to the entire surface. At this time, the low refractive index material 51 is formed so that the surface shape of each pixel 12J is convex due to the influence of the convex shape of the surface of the semiconductor substrate 21J.

[0083] In a fourteenth step, as shown in the first row of FIG. 17, the low refractive index material 51 is partially removed so as to remain only between the pixels 12J, thereby forming the inter-pixel light-shielding portions 43.

[0084] In a fifteenth step, as shown in the second row of Fig. 17, a filter 42J of a corresponding color is formed for each pixel 12J by coating. At this time, the filter 42J is formed so that the surface shape of each pixel 12J is convex due to the influence of the convex shape of the surface of the semiconductor substrate 21J.

[0085] In a sixteenth step, as shown in the third row of FIG. 17, an anti-reflection film 24 is formed on the surface of the filter 42J.

[0086] By the manufacturing method described above, it is possible to manufacture an imaging element 11J that has inter-pixel light-shielding portions 43 provided between pixels 12J, has filters 42J with convex surfaces, and can reduce the occurrence of color mixing.

[0087] <Example of electronic device configuration> The imaging element 11 as described above can be applied to various electronic devices, such as imaging systems such as digital still cameras and digital video cameras, mobile phones with imaging functions, and other devices with imaging functions.

[0088] FIG. 18 is a block diagram showing an example of the configuration of an imaging device mounted on an electronic device.

[0089] As shown in FIG. 18, an imaging device 101 includes an optical system 102, an imaging element 103, a signal processing circuit 104, a monitor 105, and a memory 106, and is capable of capturing still images and moving images.

[0090] The optical system 102 is configured to have one or more lenses, and guides image light (incident light) from a subject to the image sensor 103, forming an image on the light receiving surface (sensor section) of the image sensor 103.

[0091] The image sensor 103 is the image sensor 11 described above. Electrons are accumulated in the image sensor 103 for a certain period of time in accordance with an image formed on the light receiving surface via the optical system 102. A signal corresponding to the electrons accumulated in the image sensor 103 is then supplied to a signal processing circuit 104.

[0092] The signal processing circuit 104 performs various types of signal processing on the pixel signals output from the image sensor 103. The image (image data) obtained by the signal processing performed by the signal processing circuit 104 is supplied to a monitor 105 to be displayed, or supplied to a memory 106 to be stored (recorded).

[0093] In the imaging device 101 configured in this way, by applying the imaging element 11 described above, it is possible to capture, for example, an image with higher image quality without color mixing.

[0094] <Examples of using image sensors> FIG. 19 is a diagram showing an example of using the image sensor (imaging element) described above.

[0095] The image sensor described above can be used in various cases for sensing light such as visible light, infrared light, ultraviolet light, and X-rays, for example, as follows.

[0096] ·Digital cameras, mobile devices with camera functions, and other devices that take images for viewing purposes - Devices used for traffic purposes, such as in-vehicle sensors that take pictures of the front, rear, surroundings, and interior of a vehicle for safe driving such as automatic stopping, and for recognizing the driver's condition, surveillance cameras that monitor moving vehicles and roads, and distance measuring sensors that measure distances between vehicles. A device used in home appliances such as TVs, refrigerators, and air conditioners to capture user gestures and operate the appliances according to those gestures. -Medical and healthcare equipment, such as endoscopes and devices that take blood vessel images using infrared light - Security devices such as surveillance cameras for crime prevention and cameras for person authentication Cosmetic devices such as skin measuring devices that take pictures of the skin and microscopes that take pictures of the scalp - Devices used for sports, such as action cameras and wearable cameras for sports purposes Agricultural equipment such as cameras for monitoring the condition of fields and crops

[0097] <Configuration combination example> The present technology can also be configured as follows. (1) a semiconductor substrate on which a photoelectric conversion unit is provided for each pixel; a filter layer provided on the light-receiving surface side of the semiconductor substrate; Equipped with The filter layer includes: a filter having a curved surface is provided for each pixel; An inter-pixel light-shielding portion made of a low refractive index material having a refractive index lower than that of the filter is provided between the pixels. Solid-state imaging element. (2) a base material provided in a pattern smaller than a pixel pitch of a predetermined number of the pixels so as to be convex with respect to an insulating film formed on the surface of the semiconductor substrate; The filter is laminated on the base material, so that the surface shape is formed into a convex shape. The solid-state imaging device according to (1) above. (3) The refractive index of the base material is equal to or lower than the refractive index of the semiconductor substrate and equal to or higher than the refractive index of the inter-pixel light-shielding portion. The solid-state imaging device according to (2) above. (4) The height of the base material is equal to or less than the height of the inter-pixel light-shielding portion. The solid-state imaging device according to (2) or (3) above. (5) The filter layer is arranged in a pattern in which, for the 16 pixels of 4×4, the filters are arranged in the upper left 2×2 pixels, green in the upper right and lower left 2×2 pixels, and blue in the lower right 2×2 pixels, and this 4×4 pixel pattern is repeated. The solid-state imaging device according to any one of (1) to (4) above. (6) The undercoat material is arranged in the center of the pixel in a pattern smaller than the pixel pitch of one of the pixels. The solid-state imaging device according to (5) above. (7) The base material is arranged in the center of an area consisting of four 2×2 pixels of the same color in a pattern smaller than the pixel pitch of the four 2×2 pixels. The solid-state imaging device according to (5) above. (8) The method further includes providing an undercoat material for an insulating film formed on the surface of the semiconductor substrate so that the pixel has a pattern smaller than the pixel pitch and the pixel is recessed at the center thereof, The filter is laminated on the base material, so that the surface shape is formed into a concave shape. The solid-state imaging device according to (1) above. (9) the surface of the semiconductor substrate is formed in a convex shape for each pixel, The filter is laminated on the semiconductor substrate, so that the surface shape is formed into a convex shape. The solid-state imaging device according to (1) above. (10) a semiconductor substrate on which a photoelectric conversion unit is provided for each pixel; a filter layer provided on the light-receiving surface side of the semiconductor substrate; A method for manufacturing a solid-state imaging device comprising: The filter layer providing a filter having a curved surface shape for each pixel; providing an inter-pixel light-shielding portion between the pixels, the inter-pixel light-shielding portion being made of a low refractive index material having a refractive index lower than that of the filter; A manufacturing method comprising: (11) a semiconductor substrate on which a photoelectric conversion unit is provided for each pixel; a filter layer provided on the light-receiving surface side of the semiconductor substrate; and The filter layer includes: a filter having a curved surface is provided for each pixel; An inter-pixel light-shielding portion made of a low refractive index material having a refractive index lower than that of the filter is provided between the pixels. An electronic device equipped with a solid-state imaging device.

[0098] It should be noted that the present embodiment is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist of the present disclosure. Furthermore, the effects described in this specification are merely examples and are not intended to be limiting, and other effects may also be obtained. [Explanation of symbols]

[0099] 11 imaging element, 12 pixel, 21 semiconductor substrate, 22 filter layer, 23 insulating film, 24 anti-reflection film, 31 element isolation portion, 41 base material, 42 filter, 43 inter-pixel light shielding portion, 51 low refractive index material

Claims

1. a semiconductor substrate on which a photoelectric conversion unit is provided for each pixel; a filter layer provided on the light-receiving surface side of the semiconductor substrate; Equipped with The filter layer includes: a filter having a curved surface and a base material for controlling the surface shape of the filter are provided for each pixel; An inter-pixel light-shielding portion made of a low refractive index material having a refractive index lower than that of the filter is provided between the pixels. Solid-state imaging element.

2. The base material is provided in a pattern smaller than the pixel pitch of a predetermined number of the pixels so as to be convex with respect to an insulating film formed on the surface of the semiconductor substrate, The filter is laminated on the base material, so that the surface shape is formed into a convex shape. The solid-state imaging device according to claim 1 .

3. The refractive index of the base material is equal to or lower than the refractive index of the semiconductor substrate and equal to or higher than the refractive index of the inter-pixel light-shielding portion. The solid-state imaging device according to claim 2 .

4. The height of the base material is equal to or less than the height of the inter-pixel light-shielding portion. The solid-state imaging device according to claim 2 .

5. The filter layer is an array in which, for 16 pixels (4×4), the filters are arranged in a pattern in which red is in the upper left 2×2 pixels, green is in the upper right and lower left 2×2 pixels, and blue is in the lower right 2×2 pixels, and the 4×4 pixel pattern is repeated. The solid-state imaging device according to claim 2 .

6. The undercoat material is arranged in the center of the pixel in a pattern smaller than the pixel pitch of one of the pixels. The solid-state imaging device according to claim 5 .

7. The base material is arranged in the center of an area consisting of four 2×2 pixels of the same color in a pattern smaller than the pixel pitch of the four 2×2 pixels. The solid-state imaging device according to claim 5 .

8. The base material is provided on an insulating film formed on a surface of the semiconductor substrate so that the center of the pixel is recessed in a pattern smaller than the pixel pitch of the pixel, The filter is laminated on the base material, so that the surface shape is formed into a concave shape. The solid-state imaging device according to claim 1 .

9. In place of the base material, the surface of the semiconductor substrate is formed into a convex shape for each pixel in order to control the surface shape of the filter, The filter is laminated on the semiconductor substrate, so that the surface shape is formed into a convex shape. The solid-state imaging device according to claim 1 .

10. a semiconductor substrate on which a photoelectric conversion unit is provided for each pixel; a filter layer provided on the light-receiving surface side of the semiconductor substrate; A method for manufacturing a solid-state imaging device comprising: The filter layer providing a filter having a curved surface shape and a base material for controlling the surface shape of the filter for each pixel; providing an inter-pixel light-shielding portion between the pixels, the inter-pixel light-shielding portion being made of a low refractive index material having a refractive index lower than that of the filter; A manufacturing method comprising:

11. a semiconductor substrate on which a photoelectric conversion unit is provided for each pixel; a filter layer provided on the light-receiving surface side of the semiconductor substrate; and The filter layer includes: a filter having a curved surface and a base material for controlling the surface shape of the filter are provided for each pixel; An inter-pixel light-shielding portion made of a low refractive index material having a refractive index lower than that of the filter is provided between the pixels. An electronic device equipped with a solid-state imaging device.

Images