Imaging device, electronic apparatus, and method for manufacturing imaging device

Abstract

An imaging device according to an embodiment of the present invention comprises: a semiconductor substrate; a plurality of light-receiving parts provided inside of the semiconductor substrate for each pixel; a plurality of color filters provided to the semiconductor substrate so as to correspond to an array of the pixels; and a plurality of pillar structures provided to the plurality of color filters for each pixel, each of the pillar structures condensing light. The plurality of pillar structures are formed such that pillar arrays of the pillar structures in two pixels that are each adjacent to one pixel and have different colors are the same.

Description

Imaging apparatus, electronic device, and method of manufacturing imaging apparatus

[0001] The present disclosure relates to an imaging apparatus, an electronic device, and a method of manufacturing an imaging apparatus.

[0002] In an imaging apparatus such as a CIS (CMOS image sensor), for example, a technique using a metasurface corresponding to each color pixel has been proposed to increase the efficiency of light incidence on the surface of a semiconductor substrate (see, for example, Patent Document 1).

[0003] Japanese National Publication of International Patent Application No. 2023-509034

[0004] However, in the above-described technique, depending on the pixel arrangement, a sensitivity difference may occur between pixels, which may reduce image quality. For example, when one pixel is sandwiched between two pixels of different colors, the symmetry of incident light with respect to that one pixel cannot be maintained, resulting in a sensitivity difference that reduces image quality.

[0005] Accordingly, the present disclosure provides a technique capable of suppressing a decrease in image quality.

[0006] An imaging apparatus according to an embodiment includes: a semiconductor substrate; a plurality of light receiving units provided for each pixel inside the semiconductor substrate; a plurality of color filters provided on the semiconductor substrate in correspondence with the arrangement of the pixels; and a plurality of pillar structure units provided for each pixel on the plurality of color filters, each of which condenses light, wherein the plurality of pillar structure units are formed such that pillar arrangements of the pillar structure units are the same in the two pixels of different colors that are each adjacent to the one pixel.

[0007] An electronic device according to an embodiment includes an imaging apparatus, the imaging apparatus includes: a semiconductor substrate; a plurality of light receiving units provided for each pixel inside the semiconductor substrate; a plurality of color filters provided on the semiconductor substrate in correspondence with the arrangement of the pixels; and a plurality of pillar structure units provided for each pixel on the plurality of color filters, each of which condenses light, wherein the plurality of pillar structure units are formed such that pillar arrangements of the pillar structure units are the same in the two pixels of different colors that are each adjacent to the one pixel.

[0008] A method for manufacturing an imaging device according to an embodiment includes providing a light-receiving section for each pixel inside a semiconductor substrate, providing a plurality of color filters on the semiconductor substrate corresponding to the arrangement of the pixels, and providing a pillar structure for focusing light on each pixel on the plurality of color filters. When providing the plurality of pillar structures, the plurality of pillar structures are formed such that the pillar arrangement of the pillar structures is the same for two pixels of different colors that are adjacent to each of the pixels.

[0009] This figure shows an example configuration of an imaging device according to an embodiment. This is a plan view showing the color filter layer and pillar layer of the pixel array section according to an embodiment. This is a cross-sectional view showing an example configuration of the pixel array section according to an embodiment. This is a plan view for explaining the light-gathering area by the pillar layer according to an embodiment. This is a cross-sectional view showing an example configuration of the pixel array section of a modified example 1 according to an embodiment. This is a cross-sectional view showing an example configuration of the pixel array section of a modified example 2 according to an embodiment. This is a cross-sectional view showing an example configuration of the pixel array section of a modified example 3 according to an embodiment. This is a cross-sectional view showing an example configuration of the pixel array section of a modified example 4 according to an embodiment. This is a cross-sectional view showing an example configuration of the pixel array section of a modified example 5 according to an embodiment. This is a cross-sectional view showing an example configuration of the pixel array section of a modified example 6 according to an embodiment. This is a cross-sectional view showing an example configuration of the pixel array section of a modified example 7 according to an embodiment. This is a cross-sectional view showing an example configuration of the pixel array section of a modified example 8 according to an embodiment. This is a plan view showing an example configuration of the pixel array section of a modified example 9 according to an embodiment. This is a plan view showing an example configuration of the pixel array section of a modified example 10 according to an embodiment. This figure shows an example of the manufacturing process of an imaging device according to an embodiment. This figure shows an example of the manufacturing process of an imaging device according to an embodiment. This figure shows an example of the application of the imaging device described above. This figure shows an example configuration of the imaging device according to an application example. This figure shows an example configuration of the distance measuring device according to an application example.

[0010] Embodiments of this disclosure will be described in detail below with reference to the drawings. Embodiments include examples and modifications. However, the technology relating to this disclosure is not limited by the embodiments. In addition, in the following embodiments, the same reference numerals are used for essentially the same parts to omit redundant explanations.

[0011] This disclosure will be described in the following order of items: 1. Embodiments 1-1. Example of Imaging Device Configuration 1-2. Example of Pixel Array Configuration 1-3. Example of Light Collection and Transmission of Pillar Layer 1-4. Modification of Imaging Device 1-5. Example of Manufacturing Process for Imaging Device 1-6. Overview 2. Other Embodiments 3. Application Examples 3-1. Various Devices 3-2. Imaging Device 3-3. Distancing Device 4. Notes

[0012] <1. Embodiments> <1-1. Example of Imaging Device Configuration> An example of the configuration of the imaging device 10 according to the embodiment will be described with reference to Figure 1. Figure 1 is a diagram showing an example of the configuration of the imaging device 10 according to the embodiment.

[0013] As shown in Figure 1, the imaging device 10 comprises a pixel array unit 11, a vertical drive unit 12, a column signal processing unit 13, and a control unit 14. This imaging device 10 is, for example, a solid-state imaging device. The solid-state imaging device functions, for example, as a light detection device.

[0014] The pixel array section 11 has a plurality of pixels 100. Each pixel 100 is arranged, for example, in a two-dimensional matrix. Each of these pixels 100 receives and detects light. Specifically, each pixel 100 is equipped with a photoelectric conversion unit that performs photoelectric conversion of incident light and generates an image signal of the subject based on the irradiated incident light. For example, a photodiode is used as the photoelectric conversion unit.

[0015] Each pixel 100 is connected to a signal line 15 and a signal line 16. The pixel 100 generates an image signal controlled by a control signal transmitted via the signal line 15, and outputs the generated image signal to the column signal processing unit 13 via the signal line 16. The signal line 15 is provided for each row of the two-dimensional matrix and is commonly connected to multiple pixels 100 arranged in a single row. The signal line 16 is provided for each column of the two-dimensional matrix and is commonly connected to multiple pixels 100 arranged in a single column.

[0016] The vertical drive unit 12 generates control signals for the pixels 100. This vertical drive unit 12 generates a control signal for each row of the two-dimensional matrix of the pixel array unit 11 and outputs the generated control signals to each pixel 100 via each signal line 15.

[0017] The column signal processing unit 13 processes the image signals generated by the pixels 100. This column signal processing unit 13 simultaneously processes the image signals transmitted via the signal lines 16 from each of the pixels 100 arranged in a row of the pixel array unit 11. The processed image signals are output from the column signal processing unit 13 to the external circuitry of the imaging device 10.

[0018] Image signal processing methods include, for example, analog-to-digital conversion, which converts the analog image signal generated by pixel 100 into a digital image signal, and correlated double sampling (CDS), which removes offset errors in the image signal.

[0019] The control unit 14 controls the vertical drive unit 12 and the column signal processing unit 13. Based on data that commands the clock, operating mode, etc., input from an external circuit, the control unit 14 generates control signals to control the vertical drive unit 12 and the column signal processing unit 13. The control unit 14 then outputs a control signal to the vertical drive unit 12 via the signal line 17, and also outputs a control signal to the column signal processing unit 13 via the signal line 18.

[0020] An imaging device 10 with this configuration basically receives light incident from a subject, converts it into photoelectric energy, and outputs an electrical signal corresponding to the amount of light. The type of imaging device 10 is not particularly limited; for example, it may be a front-illuminated type or a back-illuminated type. Furthermore, the imaging device 10 may be, for example, a CMOS (Complementary Metal Oxide Semiconductor), a CCD (Charge Coupled Device), or any other type.

[0021] <1-2. Example of Pixel Array Configuration> An example of the configuration of the pixel array section 11 according to the embodiment will be described with reference to Figures 2 and 3. Figure 2 is a plan view showing the color filter layer 120 and pillar layer 130 of the pixel array section 11 according to the embodiment. Figure 3 is a cross-sectional view (cross-sectional view along line A1-A1 in Figure 2) showing an example of the configuration of the pixel array section 11 according to the embodiment.

[0022] As shown in Figure 2, the pixel array 11 has a color filter layer 120. The color filter layer 120 includes a red (R) color filter 121, a green (G) color filter 121, and a blue (B) color filter 121. As a result, the pixel array 11 has red (R) pixels 100, green (G) pixels 100, and blue (B) pixels 100, as well as infrared (IR) pixels 100. Note that the infrared (IR) pixels 100 do not have a color filter and are instead provided with, for example, a transparent layer, but a color filter may be provided.

[0023] In the example in Figure 2, four adjacent pixels 100 are arranged in a 2x2 grid, forming a set of two sets: one set of pixels 100 with R+G+G+IR and another set of pixels 100 with B+G+G+IR. These two sets are repeated in the X-axis and Y-axis directions. Pixels 100 with the same hatching in Figure 2 are pixels of the same color. This is also true in other figures.

[0024] Furthermore, a pillar layer 130 is present in the pixel array section 11. The pillar layer 130 includes several different pillar arrangement structures, for example, a pillar structure 131 of the first arrangement a, a pillar structure 131 of the second arrangement b, and a pillar structure 131 of the third arrangement c. Each pillar structure 131 is provided for each pixel 100 and each focuses light. Each pillar structure 131 is a structure containing multiple pillars. As the pillar layer 130, for example, a metasurface can be used. A metasurface is, for example, a two-dimensional arrangement of pillars that are sufficiently smaller than the wavelength of light.

[0025] Such pillar layers 130 are laminated on the color filter layer 120. The pillar structure 131 of the first array a is laminated on the R color filter 121 and the B color filter 121, and the first array a corresponds to the R pixels 100 and the B pixels 100. The pillar structure 131 of the second array b is laminated on the G color filter 121, and the second array b corresponds to the G pixels 100. The pillar structure 131 of the third array c is laminated on, for example, a transparent layer, and the third array c corresponds to the IR pixels 100.

[0026] Each pillar structure 131 is formed such that, in the X-axis direction (or Y-axis direction), the pillar arrangement of the pillar structure 131 is the same for two pixels 100 that are adjacent to a given pixel 100 and have different colors. For example, for pixels 100 of color R and B that are adjacent to pixel 100 of color G and have different colors, the pillar arrangement of the pillar structure 131 is the same first arrangement a.

[0027] In the example shown in Figure 2, each pillar structure 131 is formed such that the pillar arrangement of the pillar structure 131 is the same even for two adjacent pixels 100 that have the same color. For example, even for two adjacent G pixels 100 that have the same color as an IR pixel 100, the pillar arrangement of the pillar structure 131 is the same second arrangement b. Similarly, for two adjacent IR pixels 100 that have the same color as an IR pixel 100, the pillar arrangement of the pillar structure 131 is the same third arrangement c.

[0028] As shown in Figure 3, the pixel array section 11 includes a semiconductor substrate 110, a color filter layer 120, a transparent layer 140, and a pillar layer 130.

[0029] The semiconductor substrate 110 is a support substrate that serves as the base. The semiconductor substrate 110 is, for example, a P-type semiconductor substrate and has a pair of opposing surfaces. In the example shown in Figure 3, the top surface (for example, the back surface) is the light incident surface. As the semiconductor substrate 110, for example, a silicon wafer or the like is used.

[0030] This semiconductor substrate 110 incorporates a plurality of light-receiving units 111. Each of these light-receiving units 111 is a semiconductor region within the semiconductor substrate 110. These light-receiving units 111 are embedded and formed at predetermined positions corresponding to each of the pixels 100. A photodiode (PD) is formed in the semiconductor region by doping, for example, with an N-type impurity. The photodiode is an example of a photoelectric conversion unit.

[0031] The color filter layer 120 is stacked on the upper surface of the semiconductor substrate 110. The color filter layer 120 includes a plurality of color filters 121. A color filter 121 is provided for each pixel 100. The color filter 121 is, for example, a red (R), green (G), or blue (B) color filter. The red (R) color filter 121, the green (G) color filter 121, and the blue (B) color filter 121 are provided to realize, for example, a pixel arrangement as shown in Figure 2.

[0032] The transparent layer 140 is laminated on the upper surface of the color filter layer 120. This transparent layer 140 functions as a bonding layer that joins the pillar layer 130 to the color filter layer 120, and also functions as a planarization layer for the pillar layer 130. In the case of IR pixels 100, the transparent layer 140 is provided instead of the color filter 121.

[0033] The pillar layer 130 is laminated on the upper surface of the transparent layer 140. This pillar layer 130 has a plurality of pillar structures 131. A pillar structure 131 is provided for each pixel 100 and, for example, focuses light in a predetermined wavelength range. Each pillar structure 131 is composed of a refractive layer 13a and a plurality of refractive sections 13b. The refractive layer 13a is a layer that refracts light and has a first refractive index.

[0034] Each refracting portion 13b is provided inside the refracting layer 13a. Each of these refracting portions 13b is formed, for example, in a pillar shape. Each refracting portion 13b is a member that refracts light and has a second refractive index higher than the first refractive index. Each refracting portion 13b is arranged, for example, to realize the first arrangement a, second arrangement b, and third arrangement c described above. The pillar shape is, for example, a cylinder, but is not limited to this, and may be a polygonal prism such as a triangular prism, square prism, or hexagonal prism, or an elliptical prism, etc. The number, shape, size, and spacing of each refracting portion 13b may be adjusted as appropriate.

[0035] Furthermore, a multilayer wiring layer may be provided on the lower surface of the semiconductor substrate 110 (the surface of the semiconductor substrate 110 opposite to the color filter layer 120 side). The multilayer wiring layer includes, for example, multiple wiring layers and an interlayer insulating layer. Each wiring layer is provided with, for example, multiple wirings such as control lines.

[0036] <1-3. An Example of Light Focusing and Transmission of the Pillar Layer> An example of light focusing and transmission of the pillar layer 130 according to the embodiment will be described with reference to Figure 4. Figure 4 is a plan view illustrating the light focusing areas (for example, each light focusing area R1, R2) by the pillar layer 130 according to the embodiment.

[0037] As shown in Figure 4, there are light-gathering areas R1 and R2. Light-gathering area R1 is a light-gathering area formed by the first array a. The pillar structure 131 of the first array a is provided for the pixels 100 of B and the pixels 100 of R, and the first array a corresponds to the pixels 100 of B and the pixels 100 of R. The area (planar area) of the respective light-gathering areas R1 for the pixels 100 of B and the pixels 100 of R is the same. The light-gathering area R1 is, for example, a square, but may have other shapes. For example, each light-gathering area R1 is arranged adjacent to each other, and two adjacent light-gathering areas R1 are set so that only one side of each touches. The position of this one side is, for example, set to coincide with the center line of the pixel 100 of G (the line that divides the pixel 100 of G in half from the center).

[0038] The light-gathering area R2 is a light-gathering area formed by the second array b. The pillar structure 131 of the second array b is provided for each pixel 100 of G, and the second array b corresponds to each pixel 100 of G. The area (planar area) of each light-gathering area R2 for each pixel 100 of G is the same. The light-gathering area R2 is, for example, a square, but may have other shapes. For example, each light-gathering area R2 is arranged adjacent to each other, and two adjacent light-gathering areas R2 are set so that only their vertices touch each other. The position of these vertices is set, for example, to overlap with the center of R or B.

[0039] It should be noted that the area of the condensing area R1 is, for example, larger than the area of the condensing area R2, but is not limited thereto, and may be smaller than the area of the condensing area R2. In addition, the respective shapes (planar shapes) of the condensing areas R1 and R2 may be the same or different.

[0040] In the example of FIG. 4, the condensing area for the IR pixel 100 is not illustrated, but is actually set. That is, the pillar structures 131 of the third array c are provided for the IR pixels 100, and the third array c corresponds to the IR pixels 100. The area (planar area) of the condensing area of each IR pixel 100 is the same.

[0041] As shown in FIG. 4, the G pixel 100 located between the B pixel 100 and the R pixel 100 receives light in the wavelength band from the first array a of the B pixel 100 and light in the wavelength band from the first array a of the R pixel 100. At this time, since the pillar arrays of the B pixel 100 and the R pixel 100 are both the first array a, the light transmittance, the degree of condensing and the like are the same for each pillar array, and the symmetry of light incident on the G pixel 100 is maintained. This makes it possible to suppress the sensitivity difference between the G pixels 100, thereby suppressing deterioration in image quality.

[0042] It should be noted that, for example, if the pillar arrays of the B pixel 100 and the R pixel 100 are different from each other, the transmittance and the degree of condensing of light incident on the G pixel 100 differ depending on the pillar array, so that the symmetry of light incident on the G pixel 100 cannot be maintained. This causes a sensitivity difference between the G pixels 100, leading to deterioration in image quality.

[0043] <1-4. Modified Examples of Imaging Device> Modified Examples 1 to 10 of the imaging device 10 according to the embodiment will be described with reference to FIGS. 5 to 14. The configurations of Modified Examples 1 to 10 are basically the same as the aforementioned configuration (see FIG. 3), and the differences between these configurations will be described.

[0044] (Modified Example 1) FIG. 5 is a cross-sectional view showing a configuration example of a pixel array unit 11 according to Modified Example 1 of the embodiment.

[0045] As shown in FIG. 5, in Modification 1, a scattering portion 112 is provided for each pixel 100. Each of the scattering portions 112 is provided, for example, on the upper surface of the semiconductor substrate 110 (the surface of the semiconductor substrate 110 on the side of the color filter layer 120). Each of the scattering portions 112 has, for example, a plurality of concavo-convex portions, and scatters light by the respective concavo-convex portions. As the concavo-convex portion, for example, a pyramid-shaped concavo-convex portion is used, but concavo-convex portions of other shapes may also be used. According to Modification 1, by providing the scattering portion 112 in the pixel 100, image quality can be improved through scattering of light in the pixel 100.

[0046] (Modification 2) FIG. 6 is a cross-sectional view showing a configuration example of a pixel array unit 11 according to Modification 2 of the embodiment.

[0047] As shown in FIG. 6, in Modification 2, in addition to the configuration of Modification 1, a planarization layer 150 is provided. The planarization layer 150 is provided on the upper surface of the semiconductor substrate 110 (the surface of the semiconductor substrate 110 on the side of the color filter layer 120). That is, the planarization layer 150 is provided between the semiconductor substrate 110 and the color filter layer 120. The planarization layer 150 functions, for example, as a bonding layer for bonding the color filter layer 120 to the semiconductor substrate 110, and also functions as a planarization layer for the color filter layer 120. According to Modification 2, by providing the planarization layer 150 in the pixel 100, image quality can be improved through planarization of the color filter layer 120 and the like.

[0048] (Modification 3) FIG. 7 is a cross-sectional view showing a configuration example of a pixel array unit 11 according to Modification 3 of the embodiment.

[0049] As shown in Figure 7, in Modification 3, a plurality of light-shielding layers 122 are provided. Each of the light-shielding layers 122 is provided so as to surround the target pixel 100 on the upper surface (light incident surface) of the semiconductor substrate 110. Each of the light-shielding layers 122 may function as a layer that only shields light without separating each color filter 121, or it may function as a color filter wall that separates each color filter 121. According to Modification 3, by providing the light-shielding layers 122, image quality can be improved by improving color separation and suppressing light leakage.

[0050] (Modification 4) Figure 8 is a cross-sectional view showing an example of the configuration of the pixel array section 11 in Modification 4 according to the embodiment.

[0051] As shown in Figure 8, in Modification 4, the pillar layer 130A (each pillar structure 131) is composed of multiple layers: a first layer 132, an intermediate layer 133, and a second layer 134. The first layer 132 and the second layer 134 are the same as those of the pillar layer 130 described above (see Figure 3). The intermediate layer 133 is provided between the first layer 132 and the second layer 134. This intermediate layer 133 is a light-transmitting layer (for example, a transparent layer). According to Modification 4, since the pillar layer 130A is composed of multiple layers, the pillar arrangement of the pillar layer 130A can be easily adjusted.

[0052] (Modification 5) Figure 9 is a cross-sectional view showing an example of the configuration of the pixel array section 11 in Modification 5 according to the embodiment.

[0053] As shown in Figure 9, in Modification 5, a plurality of separation sections 113 are provided. Each of the separation sections 113 is provided at the boundary between a plurality of adjacent pixels 100 in the XY axis plane within the semiconductor substrate 110. Each of the separation sections 113 is, for example, a trench formed on the upper surface of the semiconductor substrate 110. The trench is a DTI (Deep Trench Isolation) made of an insulating material such as an oxide film, but other structures may also be used. According to Modification 5, by providing the separation sections 113, image quality can be improved by improving color separation, etc.

[0054] (Modification 6) Figure 10 is a cross-sectional view showing an example of the configuration of the pixel array section 11 in Modification 6 according to the embodiment.

[0055] As shown in Figure 10, in Modification 6, a plurality of separation sections 114 are provided. Each of the separation sections 114 is provided at the boundary between a plurality of adjacent pixels 100 in the XY axis plane within the semiconductor substrate 110, similar to the separation sections 113 described above. Each of the separation sections 114 is, for example, a through trench formed on the upper surface of the semiconductor substrate 110. According to Modification 6, by providing the separation sections 114, image quality can be improved by improving color separation, etc.

[0056] (Modification 7) Figure 11 is a cross-sectional view showing an example of the configuration of the pixel array section 11 in Modification 7 according to the embodiment.

[0057] As shown in Figure 11, in Modification 7, a B color filter 121 and an R color filter 121 are provided for the IR pixels 100. The B color filter 121 and the R color filter 121 are stacked on the upper surface of the semiconductor substrate 110 for the IR pixels 100 in the order they are described. According to Modification 7, by providing a B color filter 121 and an R color filter 121 for the IR pixels 100, image quality can be improved by improving color separation and other factors.

[0058] Although both the B color filter 121 and the R color filter 121 are provided, for example, only one of the B color filter 121 or the R color filter 121 may be provided.

[0059] (Modification 8) Figure 12 is a cross-sectional view showing an example of the configuration of the pixel array section 11 according to Modification 8 of the embodiment.

[0060] As shown in Figure 12, in Modification 8, in addition to the configuration of Modification 7, an infrared cut color filter (IR cut color filter) 123 is provided. The infrared cut color filter 123 is provided for the G pixels 100, R pixels 100, and B pixels 100. The infrared cut color filter 123 is stacked on the upper surface of the semiconductor substrate 110 for, for example, the G pixels 100, R pixels 100, and B pixels 100. According to Modification 8, by providing the infrared cut color filter 123 for the G pixels 100, R pixels 100, and B pixels 100, image quality can be improved by improving color separation and other factors.

[0061] The infrared cut color filter 123 is provided for all of the G pixels 100, R pixels 100, and B pixels 100, but for example, it may be provided for only one or two of the G pixels 100, R pixels 100, and B pixels 100.

[0062] (Modification 9) Figure 13 is a plan view showing an example of the configuration of the pixel array section 11 according to Modification 9 of the embodiment.

[0063] As shown in Figure 13, in Modification 9, the pillar structure 131 of the first array a is also stacked on the transparent layer of the IR pixels 100, and the first array a also corresponds to the IR pixels 100. That is, only the first array a and the second array b exist as pillar arrays of the pillar layer 130. In Modification 9 as well, the image quality can be improved as described above.

[0064] (Modification 10) Figure 14 is a plan view showing an example of the configuration of the pixel array section 11 of modification 10 according to the embodiment.

[0065] As shown in Figure 14, in the modified example 10, four adjacent pixels 100 are arranged in a 2x2 grid, forming a pair. There are two pairs: one with R+IR+IR+G pixels 100 and another with B+IR+IR+G pixels 100. These two pairs are repeatedly arranged in the X-axis and Y-axis directions.

[0066] The pillar structure 131 of the first array a is stacked on the R color filter 121 and the B color filter 121, and the first array a corresponds to the R pixels 100 and the B pixels 100. The pillar structure 131 of the second array b is stacked on a transparent layer, and the second array b corresponds to the IR pixels 100. The pillar structure 131 of the third array c is stacked on the G color filter 121, and the third array c corresponds to the G pixels 100. In the modified example 10, as described above, the image quality can be improved.

[0067] <1-5. Example of Manufacturing Process for Imaging Device> An example of the manufacturing process for the imaging device 10 according to the embodiment will be described with reference to Figures 15 and 16. Figures 15 and 16 are diagrams showing an example of the manufacturing process for the imaging device 10 according to the embodiment. In the examples of Figures 15 and 16, the upper diagram is a cross-sectional view, and the lower diagram is a top view.

[0068] As shown in Figure 15, a color filter layer 120 (each color filter 121), a transparent layer 140, and a refractive layer 13a (a material having a first refractive index) are stacked on the upper surface of the semiconductor substrate 110 in the order described, and a resist layer 50 with a predetermined pattern is formed on the upper surface of the refractive layer 13a. The resist layer 50 includes a plurality of through holes 51 as a predetermined pattern.

[0069] Next, a resist layer 50 with a predetermined pattern is used, and the refractive layer 13a is etched. As a result, multiple through holes 13c are formed in the refractive layer 13a. In the example shown in Figure 15, there are 12 through holes 51 and 12 through holes 13c, and each through hole 51 and each through hole 13c is formed in a cylindrical shape. These numbers and shapes are merely examples.

[0070] Next, as shown in Figure 16, a high refractive index layer 52 (a material having a second refractive index) is laminated onto the refractive index layer 13a having each through-hole 13c. As a result, the high refractive index layer 52, i.e., the material having a second refractive index, fills each through-hole 13c.

[0071] Subsequently, the upper surface of the high-refractive-index layer 52 is flattened, and a pillar layer 130 including a refractive layer 13a and multiple refractive sections 13b is formed. In the example shown in Figure 16, there are 12 refractive sections 13b, and each refractive section 13b is formed in a cylindrical shape. These numbers and shapes are merely examples.

[0072] In the manufacturing method of the imaging device 10 described above, it is possible to use general methods, equipment, and conditions for manufacturing semiconductor devices. In other words, it is possible to manufacture the imaging device 10 according to this embodiment using existing semiconductor device manufacturing methods. For example, various methods can be used to manufacture the imaging device 10, such as chemical vapor deposition, physical vapor deposition, coating methods such as spin coating, lithography, and bonding techniques for support substrates and peripheral circuit boards.

[0073] <1-6. Overview> As described above, the imaging device 10 according to the embodiment comprises a semiconductor substrate 110, a plurality of light-receiving units 111 provided inside the semiconductor substrate 110 for each pixel 100, a plurality of color filters 121 provided on the semiconductor substrate 110 corresponding to the arrangement of pixels 100, and a plurality of pillar structures 131 provided on the plurality of color filters 121 for each pixel 100, each for focusing light. The plurality of pillar structures 131 are formed such that the pillar arrangement of the pillar structures 131 is the same for two pixels 100 adjacent to one pixel 100 and of different colors (see Figures 1 to 3). As a result, the light transmittance and degree of focusing for each pillar arrangement are the same for two pixels 100 of different colors, and the symmetry of the light incident on one pixel 100 is maintained, so it is possible to suppress problems such as differences in sensitivity and suppress the deterioration of image quality.

[0074] Furthermore, the pillar arrays of the two aforementioned pixels 100 are first arrays a that focus light of two different wavelengths, and the pillar array of one of the aforementioned pixels 100 may be a second array b that focuses light of a color other than the two different colors or light of infrared wavelengths (see Figures 2 and 3). This ensures that a decrease in image quality is suppressed.

[0075] Furthermore, each of the multiple pillar structures 131 may include a refractive layer 13a having a first refractive index and a plurality of pillar-shaped refractive portions 13b provided on the refractive layer 13a, having a second refractive index higher than the first refractive index (see Figure 3). This ensures that a decrease in image quality is reliably suppressed.

[0076] Furthermore, the imaging device 10 may also include a scattering unit 112 provided on the side of the semiconductor substrate 110 facing the multiple color filters 121, which scatters light (see Figure 5). This ensures that a decrease in image quality is reliably suppressed.

[0077] Furthermore, the imaging device 10 may also include a planarization layer 150 provided between the semiconductor substrate 110 and the plurality of color filters 121 (see Figure 6). This ensures that a decrease in image quality is reliably suppressed.

[0078] Furthermore, the imaging device 10 may also include a light-shielding layer 122 provided between a plurality of color filters 121 (see Figure 7). This ensures that a decrease in image quality is reliably suppressed.

[0079] Furthermore, each of the multiple pillar structures 131 may be composed of multiple layers (see Figure 8). This ensures that a decrease in image quality is reliably suppressed.

[0080] Furthermore, the aforementioned multiple layers may include a first layer 132 and a second layer 134, and each of the first layer 132 and the second layer 134 may include a refractive layer 13a having a first refractive index and a plurality of pillar-shaped refractive portions 13b provided on the refractive layer 13a having a second refractive index higher than the first refractive index (see Figure 8). This ensures that a decrease in image quality is reliably suppressed.

[0081] Furthermore, the aforementioned multiple layers may include an intermediate layer 133 provided between the first layer 132 and the second layer 134 (see Figure 8). This ensures that a decrease in image quality is reliably suppressed.

[0082] Furthermore, the imaging device 10 may also include a separation unit 113 or separation unit 114 provided between the multiple light-receiving units 111 to divide the multiple light-receiving units 111 (see Figures 9 and 10). This ensures that a decrease in image quality is reliably suppressed.

[0083] Furthermore, the separation section 113 may be a trench formed in the semiconductor substrate 110 (see Figure 9). This ensures that a decrease in image quality is reliably suppressed.

[0084] Furthermore, the separation section 114 may be a through-trench penetrating the semiconductor substrate 110 (see Figure 10). This ensures that a decrease in image quality is reliably suppressed.

[0085] Furthermore, the plurality of pixels 100 may include infrared pixels 100, and the plurality of color filters 121 may include one or both of a red color filter 121 and a blue color filter 121, with one or both of the red color filter 121 and the blue color filter 121 being provided for the infrared pixels 100 (see Figure 11). This ensures that a decrease in image quality is suppressed.

[0086] Furthermore, the plurality of pixels 100 may include one, two, or all of the red, green, and blue pixels 100, and the plurality of color filters 121 may include infrared cut color filters 123, with the infrared cut color filters 123 being provided for one, two, or all of the red, green, and blue pixels 100 (see Figure 12). This ensures that a decrease in image quality is reliably suppressed.

[0087] Furthermore, the two aforementioned pixels 100 may be arranged with one pixel 100 in between them (see Figures 2, 13, and 14). Even with such a configuration, a decrease in image quality can be suppressed.

[0088] Furthermore, the two aforementioned pixels 100 may be a red pixel 100 and a blue pixel 100, and the aforementioned single pixel 100 may be a green pixel 100 (see Figures 2 and 13). Even with such a configuration, the degradation of image quality can be suppressed.

[0089] Furthermore, the two aforementioned pixels 100 may be a red pixel 100 and a blue pixel 100, and the aforementioned single pixel 100 may be an infrared pixel 100 (see Figure 14). Even with such a configuration, the degradation of image quality can be suppressed.

[0090] Furthermore, the multiple pillar structures 131 may be formed such that the pillar arrangement of the pillar structures 131 is the same for two adjacent pixels 100 that have the same color (see Figures 2, 13, and 14). This ensures that a decrease in image quality is reliably suppressed.

[0091] <2. Other Embodiments> The configurations and processes described in the above-described embodiments (including examples and modifications) may be implemented in various other forms besides those described above. For example, the configurations and processes may be in various forms, not limited to the examples described above. Also, for example, the configurations, processing procedures, specific names, and information including various data and parameters shown in the above document and drawings may be changed at will unless otherwise specified.

[0092] Furthermore, the configurations and processes described in the above-mentioned embodiments (including examples and modifications) do not necessarily have to be physically configured as shown in the figures. In other words, the specific forms of distribution and integration of each configuration and process are not limited to those shown in the figures, and all or part of them may be functionally or physically distributed and integrated in any unit depending on various loads and usage conditions.

[0093] Furthermore, the various configurations and processes described in the above-mentioned embodiments (including examples and modifications) may be combined as appropriate. For example, at least a part of one embodiment may be combined with at least a part of another embodiment as appropriate. Also, the effects described in the embodiments are merely illustrative and not limiting, and other effects may also occur.

[0094] <3. Application Examples> <3-1. Various Devices> Application examples of the imaging device 10 described above will be explained with reference to Figure 17. Figure 17 is a diagram showing application examples of the imaging device 10 described above. The imaging device 10 may be applied to various cases, i.e., various devices (an example of electronic equipment), as follows.

[0095] As shown in Figure 17, the imaging device 10 can be used in, for example, "devices that capture images for viewing purposes, such as digital cameras and portable devices with camera functions," "devices used for traffic purposes, such as in-vehicle sensors that photograph the front, rear, surroundings, and interior of a vehicle for safe driving such as automatic stopping and recognition of the driver's condition, surveillance cameras that monitor moving vehicles and roads, and distance measuring sensors that measure distances between vehicles," "devices used in home appliances such as TVs, refrigerators, and air conditioners to capture user gestures and operate the device according to those gestures," "devices used for medical and healthcare purposes, such as endoscopes and devices that perform angiography by receiving infrared light," "devices used for security purposes, such as surveillance cameras for crime prevention and cameras for person recognition," "devices used for beauty purposes, such as skin measuring devices that photograph skin and microscopes that photograph the scalp," "devices used for sports purposes, such as action cameras and wearable cameras for sports use," and "devices used for agriculture, such as cameras for monitoring the condition of fields and crops."

[0096] Furthermore, the technology disclosed herein can be applied to a variety of products. For example, the technology disclosed herein may be implemented as electronic equipment mounted on any type of mobile device, such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, robots, construction machinery, or agricultural machinery (tractors). Alternatively, for example, the technology disclosed herein may be implemented as electronic equipment mounted on endoscopic surgical systems or microsurgical systems.

[0097] <3-2. Imaging Device> The imaging device 1000 according to the application example will be described with reference to Figure 18. Figure 18 is a diagram showing an example configuration of the imaging device 1000 according to the application example. This imaging device 1000 is an example of an electronic device to which the aforementioned imaging device 10 is applied. Examples of imaging devices 1000 include digital still cameras, video cameras, smartphones and mobile phones with imaging functions, and other electronic devices.

[0098] As shown in Figure 18, the imaging device 1000 includes an optical system 1001, a shutter device 1002, an image sensor (solid-state imager) 1003, a control circuit (drive circuit) 1004, a signal processing circuit 1005, a monitor 1006, and a memory 1007. This imaging device 1000 is capable of capturing both still and moving images.

[0099] The optical system 1001 has one or more lenses. This optical system 1001 guides light from the subject (incident light) to the image sensor 1003 and forms an image on the light-receiving surface of the image sensor 1003.

[0100] The shutter device 1002 is positioned between the optical system 1001 and the image sensor 1003. The shutter device 1002 controls the light illumination period and the light shielding period for the image sensor 1003 according to the control of the control circuit 1004.

[0101] The image sensor 1003 accumulates signal charge for a certain period of time in response to light formed on the light-receiving surface via the optical system 1001 and shutter device 1002. The signal charge accumulated in the image sensor 1003 is transferred according to a drive signal (timing signal) supplied from the control circuit 1004. For example, the aforementioned imaging device 10 is used as the image sensor 1003.

[0102] The control circuit 1004 drives the image sensor 1003 and the shutter device 1002 by outputting drive signals that control the transfer operation of the image sensor 1003 and the shutter operation of the shutter device 1002.

[0103] The signal processing circuit 1005 performs various signal processing operations on the signal charge output from the image sensor 1003. The image (image data) obtained by the signal processing circuit 1005 is supplied to the monitor 1006 and also to the memory 1007.

[0104] The monitor 1006 displays a video or still image captured by the image sensor 1003 based on image data supplied from the signal processing circuit 1005. For example, the monitor 1006 may be a panel-type display device such as a liquid crystal panel or an organic EL (Electro-Luminescence) panel.

[0105] The memory 1007 stores image data supplied from the signal processing circuit 1005, that is, image data of moving or still images captured by the image sensor 1003. Various types of memory can be used as the memory 1007.

[0106] Even with an imaging device 1000 having such a configuration, the same effects as in the above-described embodiment can be obtained by applying the aforementioned imaging device 10.

[0107] <3-3. Distance Measuring Device> The distance measuring device 2000 according to the application example will be described with reference to Figure 19. Figure 19 is a diagram showing an example configuration of the distance measuring device 2000 according to the application example. This distance measuring device 2000 is an example of an electronic device to which the aforementioned imaging device 10 is applied.

[0108] As shown in Figure 19, the distance measuring device (distance image sensor) 2000 comprises a light source unit 2001, an optical system 2002, an image sensor (solid-state imager) 2003, a control circuit (drive circuit) 2004, a signal processing circuit 2005, a monitor 2006, and a memory 2007. This distance measuring device 2000 projects light from the light source unit 2001 toward the subject and receives the light (modulated light or pulsed light) reflected from the surface of the subject, thereby acquiring a distance image corresponding to the distance to the subject.

[0109] The light source unit 2001 projects light toward the subject. Examples of light sources used for the light source unit 2001 include a vertical cavity surface-emitting laser (VCSEL) array that emits laser light as a surface light source, and a laser diode array in which laser diodes are arranged in a line. The laser diode array is supported by a predetermined drive unit (not shown) and scanned in a direction perpendicular to the arrangement of the laser diodes.

[0110] The optical system 2002 has one or more lenses. This optical system 2002 guides light from the subject (incident light) to the image sensor 2003 and forms an image on the light-receiving surface (sensor part) of the image sensor 2003.

[0111] The image sensor 2003 accumulates signal charge in response to light formed on the light-receiving surface via the optical system 2002. A distance signal indicating the distance, determined from the light-receiving signal (APD OUT) output from the image sensor 2003, is supplied to the signal processing circuit 2005. For example, the aforementioned imaging device 10 is used as the image sensor 2003.

[0112] The control circuit 2004 outputs drive signals (control signals) that control the operation of the light source unit 2001 and the image sensor 2003, and drives the light source unit 2001 and the image sensor 2003.

[0113] The signal processing circuit 2005 performs various signal processing operations on the distance signal supplied from the image sensor 2003. For example, the signal processing circuit 2005 performs image processing (e.g., histogram processing and peak detection processing) to construct a distance image based on the distance signal. The image (image data) obtained by the signal processing circuit 2005 is supplied to the monitor 2006 and also to the memory 2007.

[0114] The monitor 2006 displays the distance image captured by the image sensor 2003 based on the image data supplied from the signal processing circuit 2005. For example, a panel-type display device such as a liquid crystal panel or an organic EL panel can be used as the monitor 2006.

[0115] The memory 2007 stores image data supplied from the signal processing circuit 2005, that is, image data of the distance image captured by the image sensor 2003. Various types of memory can be used as the memory 2007.

[0116] Even in a distance measuring device 2000 with this configuration, the same effects as in the above-described embodiment can be obtained by applying the imaging device 10 described above.

[0117] As described above, the imaging device 10 can be mounted on various electronic devices. For example, in addition to the imaging device 1000 and the distance measuring device 2000, the imaging device 10 may be mounted on various electronic devices such as notebook PCs (Personal Computers), mobile devices (e.g., smartphones and tablet PCs), PDAs (Personal Digital Assistants), wearable devices, game consoles, and music players.

[0118] <4. Addendum> The technology can also be configured as follows: (1) An imaging device comprising: a semiconductor substrate; a plurality of light-receiving units provided inside the semiconductor substrate for each pixel; a plurality of color filters provided on the semiconductor substrate corresponding to the arrangement of the pixels; and a plurality of pillar structures provided on the plurality of color filters for each pixel, each for focusing light, wherein the plurality of pillar structures are formed such that the pillar arrangement of the pillar structures is the same for two pixels of different colors that are adjacent to each of the pixels. (2) The imaging device according to (1), wherein the pillar arrangement of each of the two pixels is a first arrangement that focuses light of two different wavelengths of color, and the pillar arrangement of one pixel is a second arrangement that focuses light of a color other than the two different colors or light of infrared wavelength. (3) The imaging apparatus according to (1) or (2), wherein each of the plurality of pillar structures includes a refractive layer having a first refractive index and a plurality of pillar-shaped refractive portions provided on the refractive layer and having a second refractive index higher than the first refractive index. (4) The imaging apparatus according to any one of (1) to (3), further comprising a scattering portion provided on the surface of the semiconductor substrate on the plurality of color filters side for scattering light. (5) The imaging apparatus according to any one of (1) to (4), further comprising a planarization layer provided between the semiconductor substrate and the plurality of color filters. (6) The imaging apparatus according to any one of (1) to (5), further comprising a light-shielding layer provided between the plurality of color filters. (7) The imaging apparatus according to any one of (1) to (6), wherein each of the plurality of pillar structures is composed of multiple layers. (8) The imaging apparatus according to (7), wherein the plurality of layers includes a first layer and a second layer, and each of the first layer and the second layer includes a refractive layer having a first refractive index and a plurality of pillar-shaped refractive portions provided in the refractive layer and having a second refractive index higher than the first refractive index. (9) The imaging apparatus according to (8), wherein the plurality of layers includes an intermediate layer provided between the first layer and the second layer.(10) The imaging apparatus according to any one of (1) to (9), further comprising a separation section provided between the plurality of light-receiving sections and dividing the plurality of light-receiving sections. (11) The imaging apparatus according to (10), wherein the separation section is a trench formed in the semiconductor substrate. (12) The imaging apparatus according to (11), wherein the trench is a through trench penetrating the semiconductor substrate. (13) The imaging apparatus according to any one of (1) to (12), wherein the plurality of pixels include infrared pixels, the plurality of color filters include one or both of a red color filter and a blue color filter, and one or both of the red color filter and the blue color filter are provided for the infrared pixels. (14) The imaging device according to any one of (1) to (13), wherein the plurality of pixels include one, two, or all of the pixels of red, green, and blue, and the plurality of color filters include an infrared cut color filter, and the infrared cut color filter is provided for one, two, or all of the pixels of red, green, and blue. (15) The imaging device according to any one of (1) to (14), wherein the two pixels are provided with the one pixel between them. (16) The imaging device according to any one of (1) to (15), wherein the two pixels are a red pixel and a blue pixel, and the one pixel is a green pixel. (17) The imaging device according to any one of (1) to (15), wherein the two pixels are a red pixel and a blue pixel, and the one pixel is an infrared pixel. (18) The imaging apparatus according to any one of (1) to (17), wherein the plurality of pillar structures are formed such that the pillar arrangement of the pillar structures is the same for two pixels adjacent to each of the pixels that have the same color.(19) An electronic device comprising an imaging device, the imaging device comprising: a semiconductor substrate; a plurality of light-receiving units provided inside the semiconductor substrate for each pixel; a plurality of color filters provided on the semiconductor substrate corresponding to the arrangement of the pixels; and a plurality of pillar structures provided on the plurality of color filters for each pixel, each for focusing light, wherein the plurality of pillar structures are formed such that the pillar arrangement of the pillar structures is the same for two pixels of different colors adjacent to a single pixel. (20) A method for manufacturing an imaging device, comprising: providing a light-receiving unit for each pixel inside a semiconductor substrate; providing a plurality of color filters on the semiconductor substrate corresponding to the arrangement of the pixels; and providing pillar structures on the plurality of color filters for focusing light to each pixel, wherein, when a plurality of pillar structures are provided, the plurality of pillar structures are formed such that the pillar arrangement of the pillar structures is the same for two pixels of different colors adjacent to a single pixel. (21) An electronic device comprising an imaging device as described in any one of (1) to (18). (22) A method for manufacturing an imaging device, comprising manufacturing an imaging device as described in any one of (1) to (18).

[0119] 10 Imaging device 11 Pixel array section 12 Vertical drive section 13 Column signal processing section 13a Refraction layer 13b Refraction section 13c Through hole 14 Control section 15 Signal line 16 Signal line 17 Signal line 18 Signal line 50 Resist layer 51 Through hole 52 High refractive index layer 100 Pixel 110 Semiconductor substrate 111 Light receiving section 112 Scattering section 113 Separation section 114 Separation section 120 Color filter layer 121 Color filter 122 Light shielding layer 123 Infrared cut color filter 130 Pillar layer 130A Pillar layer 131 Pillar structure section 132 First layer 133 Intermediate layer 134 Second layer 140 Transparent layer 150 Planarization layer a First array b Second array c Third array R1 Focusing area R2 Focusing area

Claims

1. An imaging device comprising: a semiconductor substrate; a plurality of light-receiving units provided inside the semiconductor substrate for each pixel; a plurality of color filters provided on the semiconductor substrate corresponding to the arrangement of the pixels; and a plurality of pillar structures provided on the plurality of color filters for each pixel, each for focusing light, wherein the plurality of pillar structures are formed such that the pillar arrangement of the pillar structures is the same for two pixels of different colors that are adjacent to each of the pixels.

2. The imaging apparatus according to claim 1, wherein the pillar array of each of the two pixels is a first array that focuses light of two different wavelengths, and the pillar array of one pixel is a second array that focuses light of a color other than the two different colors or light of infrared wavelength.

3. The imaging apparatus according to claim 1, wherein each of the plurality of pillar structures includes a refractive layer having a first refractive index and a plurality of pillar-shaped refractive portions provided on the refractive layer and having a second refractive index higher than the first refractive index.

4. The imaging apparatus according to claim 1, further comprising a scattering portion provided on the surface of the plurality of color filters on the semiconductor substrate for scattering light.

5. The imaging apparatus according to claim 1, further comprising a planarization layer provided between the semiconductor substrate and the plurality of color filters.

6. The imaging apparatus according to claim 1, further comprising a light-shielding layer provided between the plurality of color filters.

7. The imaging apparatus according to claim 1, wherein each of the plurality of pillar structures is composed of multiple layers.

8. The imaging apparatus according to claim 7, wherein the plurality of layers include a first layer and a second layer, and each of the first layer and the second layer includes a refractive layer having a first refractive index and a plurality of pillar-shaped refractive portions provided in the refractive layer and having a second refractive index higher than the first refractive index.

9. The imaging apparatus according to claim 8, wherein the plurality of layers include an intermediate layer provided between the first layer and the second layer.

10. The imaging apparatus according to claim 1, further comprising a separation unit provided between the plurality of light-receiving units and separating the plurality of light-receiving units.

11. The imaging apparatus according to claim 10, wherein the separation portion is a trench formed in the semiconductor substrate.

12. The imaging apparatus according to claim 11, wherein the trench is a through trench that penetrates the semiconductor substrate.

13. The imaging apparatus according to claim 1, wherein the plurality of pixels include infrared pixels, the plurality of color filters include one or both of a red color filter and a blue color filter, and one or both of the red color filter and the blue color filter are provided for the infrared pixels.

14. The imaging apparatus according to claim 1, wherein the plurality of pixels include one, two, or all of the pixels of red, green, and blue, the plurality of color filters include an infrared cut color filter, and the infrared cut color filter is provided for one, two, or all of the pixels of red, green, and blue.

15. The imaging apparatus according to claim 1, wherein the two pixels are provided with the one pixel in between.

16. The imaging apparatus according to claim 1, wherein the two pixels are a red pixel and a blue pixel, and the one pixel is a green pixel.

17. The imaging apparatus according to claim 1, wherein the two pixels are a red pixel and a blue pixel, and the one pixel is an infrared pixel.

18. The imaging apparatus according to claim 1, wherein the plurality of pillar structures are formed such that the pillar arrangement of the pillar structures is the same for two pixels adjacent to each other that have the same color.

19. An electronic device comprising an imaging device, the imaging device comprising: a semiconductor substrate; a plurality of light-receiving units provided inside the semiconductor substrate for each pixel; a plurality of color filters provided on the semiconductor substrate corresponding to the arrangement of the pixels; and a plurality of pillar structures provided on the plurality of color filters for each pixel, each for focusing light, wherein the plurality of pillar structures are formed such that the pillar arrangement of the pillar structures is the same for two pixels of different colors adjacent to each of the pixels.

20. A method for manufacturing an imaging device, comprising: providing a light-receiving portion for each pixel inside a semiconductor substrate; providing a plurality of color filters on the semiconductor substrate corresponding to the arrangement of the pixels; and providing a pillar structure portion for focusing light on each pixel in the plurality of color filters, wherein, when a plurality of the pillar structures portion is provided, the plurality of pillar structures portion are formed such that the pillar arrangement of the pillar structures portion is the same for two pixels of different colors adjacent to each of the pixels.

Images