Solid-state imaging device and electronic device

Abstract

The present invention provides a solid-state imaging device capable of increasing pixel sensitivity and preventing color mixture. The solid-state imaging device is provided with: a plurality of microlenses that collect incident light; a plurality of color filters that transmit light of a specific wavelength included in the collected incident light; a plurality of photoelectric conversion parts on which the light of the specific wavelength transmitted through the color filters is incident; and a multistage waveguide wall part disposed between the color filters and surrounding the periphery of the color filter. Each multistage waveguide wall part is formed at a position where a pupil correction has been performed.

Description

[Technical field]

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

[0002] Conventionally, a solid-state imaging device has been proposed that has a pixel region in which a photoelectric conversion section, a transparent insulating layer, a color filter, and a microlens are laminated in this order (for example, see Patent Document 1). In the solid-state imaging device described in Patent Document 1, a separator containing a low refractive index material is disposed between color filters, and a waveguide is formed with the color filter as a core and the separator (waveguide wall section) as a clad, preventing diffusion of incident light within the color filter and improving the sensitivity of each pixel. Moreover, on the edge side of the pixel area (high image height), the incident light is obliquely incident on the microlens. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 073402 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the solid-state imaging device described in Patent Document 1, for example, when incident light is obliquely incident, the incident light hits the microlens side of the waveguide wall, and part of the incident light is vignetted (scattered) by the waveguide wall, and the scattered light may enter adjacent pixels, resulting in color mixing. An object of the present disclosure is to provide a solid-state imaging device and electronic device capable of increasing pixel sensitivity and preventing color mixing. [Means for solving the problem]

[0005] The solid-state imaging device of the present disclosure includes (a) a plurality of microlenses that collect incident light, (b) a plurality of color filters that transmit light of specific wavelengths contained in the collected incident light, (c) a plurality of photoelectric conversion units to which the light of the specific wavelengths that has passed through the color filters is incident, and (d) a plurality of stages of waveguide wall portions disposed between the color filters and surrounding the periphery of the color filters, and (e) each of the plurality of stages of waveguide wall portions is formed at a position where pupil correction has been performed.

[0006] The electronic device of the present disclosure includes (a) a solid-state imaging device including a plurality of microlenses that collect incident light, a plurality of color filters that transmit light of a specific wavelength contained in the collected incident light, a plurality of photoelectric conversion units to which the light of the specific wavelength that has transmitted through the color filters is incident, and a plurality of stages of waveguide wall portions arranged between the color filters and surrounding the periphery of the color filters, each of the plurality of stages of waveguide wall portions being formed at a position where pupil correction has been performed, (b) an optical lens that focuses image light from a subject on an imaging surface of the solid-state imaging device, and (c) a signal processing circuit that performs signal processing on a signal output from the solid-state imaging device. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an overall configuration of a solid-state imaging device according to a first embodiment. [Diagram 2] 2 is a diagram showing a cross-sectional configuration of the solid-state imaging device taken along line AA in FIG. [Diagram 3] 11A and 11B are diagrams showing the direction of deviation of the waveguide walls at each stage. [Figure 4] FIG. 13 is a diagram showing the amount of deviation of the waveguide wall portions at each stage. [Figure 5A] 1 is a diagram showing a flow of a manufacturing process for a solid-state imaging device. [Figure 5B] 1 is a diagram showing a flow of a manufacturing process for a solid-state imaging device. [Figure 5C] 1 is a diagram showing a flow of a manufacturing process for a solid-state imaging device. [Figure 5D] 1 is a diagram showing a flow of a manufacturing process for a solid-state imaging device. [Figure 5E] 1 is a diagram showing a flow of a manufacturing process for a solid-state imaging device. [Figure 6] FIG. 13 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a modified example. [Figure 7] FIG. 13 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a modified example. [Figure 8] FIG. 13 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a modified example. [Figure 9] FIG. 13 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a modified example. [Figure 10] FIG. 13 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a modified example. [Figure 11] FIG. 13 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a modified example. [Figure 12] FIG. 13 is a diagram showing a cross-sectional configuration of a solid-state imaging device according to a modified example. [Figure 13] FIG. 11 is a schematic configuration diagram of an electronic device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An example of a solid-state imaging device 1 and an electronic device according to an embodiment of the present disclosure will be described below with reference to FIGS. 1 to 13. The embodiments of the present disclosure will be described in the following order. Note that the present disclosure is not limited to the following examples. Also, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0009] 1. First embodiment: solid-state imaging device 1-1 Overall configuration of solid-state imaging device 1-2 Main components 1-3 Method for forming color filter layer 1-4 Variations 2. Second embodiment: Application to electronic devices

[0010] 1. First embodiment: solid-state imaging device [1-1 Overall configuration of solid-state imaging device] A solid-state imaging device 1 according to a first embodiment of the present disclosure will be described below. Fig. 1 is a schematic configuration diagram showing the entire solid-state imaging device 1 according to the first embodiment of the present disclosure. The solid-state imaging device 1 in Fig. 1 is a back-illuminated CMOS (Complementary Metal Oxide Semiconductor) image sensor. As shown in Fig. 13, the solid-state imaging device 1 (101) captures image light (incident light 106) from a subject via an optical lens 102, converts the amount of incident light 106 focused on an imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs the electrical signal. As shown in FIG. 1, the solid-state imaging device 1 includes a substrate 2, a pixel region 3, a vertical drive circuit 4, a column signal processing circuit 5, a horizontal drive circuit 6, an output circuit 7, and a control circuit 8.

[0011] The pixel region 3 has a plurality of pixels 9 regularly arranged in a two-dimensional array on the substrate 2. Each pixel 9 has a photoelectric conversion unit 23 shown in FIG. 2 and a plurality of pixel transistors (not shown). As the plurality of pixel transistors, for example, four transistors can be used: a transfer transistor, a reset transistor, a selection transistor, and an amplifier transistor. Alternatively, for example, three transistors excluding the selection transistor may be used.

[0012] The vertical drive circuit 4 is configured with, for example, a shift register, selects a desired pixel drive wiring 10, supplies a pulse for driving the pixels 9 to the selected pixel drive wiring 10, and drives each pixel 9 row by row. That is, the vertical drive circuit 4 selects and scans each pixel 9 in the pixel region 3 row by row in the vertical direction, and supplies a pixel signal based on a signal charge generated in the photoelectric conversion unit 23 of each pixel 9 according to the amount of received light to the column signal processing circuit 5 through the vertical signal line 11.

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

[0014] The output circuit 7 performs signal processing on the pixel signals sequentially supplied from each of the column signal processing circuits 5 through the horizontal signal line 12, and outputs the processed signal. For example, the signal processing may include buffering, black level adjustment, column variation correction, various types of digital signal processing, and the like. The control circuit 8 generates clock signals and control signals that serve as a reference for the operation of the vertical drive circuit 4, the column signal processing circuit 5, the horizontal drive circuit 6, etc., based on the vertical synchronization signal, the horizontal synchronization signal, and the master clock signal. Then, the control circuit 8 outputs the generated clock signals and control signals to the vertical drive circuit 4, the column signal processing circuit 5, the horizontal drive circuit 6, etc.

[0015] [1-2 Main components] Next, a detailed structure of the solid-state imaging device 1 of Fig. 1 will be described. Fig. 2 is a diagram showing a cross-sectional configuration of the solid-state imaging device 1 taken along line AA of Fig. 1. As shown in FIG. 2, the solid-state imaging device 1 includes an absorption layer 16 formed by laminating a substrate 2, an insulating film 13, a light-shielding film 14, and a planarization film 15 in this order. A light-collecting layer 19 formed by laminating a color filter layer 17 and a microlens array 18 in this order is formed on the surface of the absorption layer 16 facing the planarization film 15 (hereinafter also referred to as the "rear surface S1"). A wiring layer 20 and a support substrate 21 are laminated in this order on the surface of the absorption layer 16 facing the substrate 2 (hereinafter also referred to as the "front surface S2"). Since the rear surface S1 of the absorption layer 16 and the rear surface of the planarization film 15 are the same surface, the rear surface of the planarization film 15 will also be referred to as the "rear surface S1" in the following description. Since the front surface S2 of the absorption layer 16 and the front surface of the substrate 2 are the same surface, the front surface of the substrate 2 will also be referred to as the "front surface S2" in the following description.

[0016] The substrate 2 is configured by a semiconductor substrate made of, for example, silicon (Si), and forms a pixel region 3. In the pixel region 3, a plurality of pixels 9, each including a photoelectric conversion unit 23, are arranged in a two-dimensional array. Each of the photoelectric conversion units 23 is embedded in the substrate 2 to configure a photodiode, generates a signal charge according to the amount of incident light 22, and accumulates the generated signal charge. Moreover, each photoelectric conversion unit 23 is physically separated by a pixel separation unit 24. The pixel separation unit 24 is formed in a lattice shape so as to surround each photoelectric conversion unit 23. The pixel separation unit 24 has a bottomed trench unit 25 (groove unit) formed in the depth direction from the surface (hereinafter also referred to as the "rear surface S3") of the substrate 2 facing the insulating film 13. The trench unit 25 is formed in a lattice shape so that the inner side surface and the bottom surface form the outer shape of the pixel separation unit 24. Furthermore, the insulating film 13 covering the rear surface S3 side of the substrate 2 is embedded inside the trench unit 25.

[0017] The insulating film 13 continuously covers the entire back surface S3 side (the entire light receiving surface side) of the substrate 2 and the inside of the trench portion 25. For example, an insulating material can be used as the material of the insulating film 13. Specifically, silicon oxide (SiO2) and silicon nitride (SiN) can be used. The light shielding film 14 is formed in a lattice shape on a part of the back surface S4 side of the insulating film 13, opening the light receiving surface side of each of the multiple photoelectric conversion units 23, so that light does not leak into the adjacent pixels 9. The planarizing film 15 continuously covers the entire back surface S5 side (the entire light receiving surface side) of the insulating film 13 including the light shielding film 14, so that the back surface S1 of the light receiving layer 16 is a flat surface without unevenness.

[0018] The color filter layer 17 has a waveguide module 26 for each pixel 9 on the back surface S1 side (light receiving surface side) of the planarization film 15. The waveguide module 26 is configured by stacking multiple stages of waveguides 27. Fig. 2 illustrates a case where the number of stages of the waveguide 27 is three, and the height of all the stages of the waveguide wall portion 29 is the same as the height of all the stages of the filter component member 28. Each of the waveguides 27 has a filter component member 28 and a waveguide wall portion 29 (separation portion). The filter component 28 is an optical filter that transmits light of a specific wavelength contained in the incident light 22 collected by the microlens 30. For example, red light, green light, and blue light can be used as the light of the specific wavelength. In addition, the filter component 28 that transmits light of the same color is used as each of the filter component members 28 included in the same waveguide module 26. In this way, a color filter 33 is formed including the filter component members 28 in multiple stages that the waveguide module 26 has. The light of the specific wavelength that has transmitted through the color filter 33 is incident on the photoelectric conversion unit 23. In addition, as the arrangement pattern of the filter component members 28 when viewed from the microlens 30 side, for example, a Bayer arrangement can be used. As the material of the filter component members 28, for example, an organic glass material with a refractive index of 1.4 to 1.9 can be used.

[0019] The waveguide wall 29 is formed so as to surround the filter component 28 included in the same waveguide 27. The waveguide wall 29 is present in the same stage and is shared between the adjacent waveguides 27. That is, the waveguide wall 29 in each stage is formed in a lattice shape so as to surround the filter component 28 in the same stage. In other words, the waveguide wall 29 in a plurality of stages is disposed between the color filters 33 formed by the filter component 28 in all stages. As the material of the waveguide wall 29, for example, a low refractive index material having a refractive index lower than that of the filter component 28 included in the same waveguide 27 can be used. As the low refractive index material, for example, a low refractive index resin having a refractive index of 1.0 to 1.2 can be used. As a result, the waveguide 27 forms a core with the filter component 28 having a relatively high refractive index, and forms a cladding with the waveguide wall 29 having a relatively low refractive index. 2 illustrates an example in which the height, width, and material of the waveguide wall 29 of each stage are the same. That is, the waveguide wall 29 of each stage is made of the same shape and material. Note that the "width of the waveguide wall 29" refers to the width of the waveguide wall 29 in a cross section perpendicular to the back surface S3 (light-receiving surface) of the substrate 2, in a direction parallel to the back surface S3 (light-receiving surface) of the substrate 2. For example, when the waveguide wall 29 is viewed from the microlens 30 side, the length of the waveguide wall 29 in a direction intersecting (orthogonal, etc.) the direction in which the waveguide wall 29 extends can be mentioned.

[0020] Further, each of the multiple stages of waveguide wall portions 29 is formed at a position where pupil correction is individually performed. That is, at the end side (high image height) of the pixel region 3, pupil correction is performed on each of the multiple waveguides 27 included in each waveguide module 26. Specifically, as shown in FIG. 2 and FIG. 3, in each of the mutually stacked waveguide wall portions 29, the waveguide wall portion 29 of the step on the microlens array 18 side (microlens 30 side) is shifted toward the center of the pixel region 3 more than the waveguide wall portion 29 of the step on the photoelectric conversion unit 23 side. In FIG. 2, the central axis of the lower stage waveguide wall portion 29 coincides with the central axis of the pixel separation unit 24, the central axis of the middle stage waveguide 27 is shifted toward the center of the pixel region 3 more than the central axis of the lower stage waveguide wall portion 29, and the central axis of the upper stage waveguide wall portion 29 is shifted toward the center of the pixel region 3 more than the central axis of the middle stage waveguide 27. 3, when viewed from the microlens array 18 side, the waveguide module 26 in the region on the left side of the center of the pixel region 3 has the middle and upper waveguide wall portions 29 shifted to the right in FIG. 3, the waveguide module 26 in the region below the center of the pixel region 3 has the middle and upper waveguide wall portions 29 shifted to the upper side in FIG. 3, and the waveguide module 26 in the region on the lower left side of the center of the pixel region 3 has the middle and upper waveguide wall portions 29 shifted to the upper right side in FIG. 3. In FIG. 3, the filter component 28 is omitted to make it easier to understand the shifted state of the waveguide wall portions 29. FIG. 3 also illustrates a case where the shift amounts of the waveguide wall portions 29 of each stage are the same.

[0021] 4, the amount of misalignment between the top waveguide wall 29 and the bottom waveguide wall 29 increases as the distance from the center of the pixel region 3 increases as viewed from the microlens array 18 side. In FIG. 4, the misalignment between the waveguide walls 29 in the waveguide module 26 in the center of the pixel region 3 (=0)<the amount of misalignment between the waveguide walls 29 in the waveguide module 26 in an area slightly away from the center of the pixel region 3<the amount of misalignment between the waveguide walls 29 in the waveguide module 26 in an area significantly away from the pixel region 3. Among the mutually stacked waveguide walls 29, the amount of misalignment of the waveguide wall 29 in the step on the microlens array 18 side is within the range of ±x / 2 with respect to the width x of the waveguide wall 29 in the step on the photoelectric conversion unit 23 side. That is, the amount of misalignment is determined so that there is no gap between the mutually stacked waveguide walls 29.

[0022] The optimal shift amount z of the waveguide wall portion 29 can be calculated, for example, from Snell's law. Specifically, as shown in Fig. 2, it can be calculated according to the following formula (1) based on the incident angle A [deg] of the incident light 22, the refractive index n of the filter component 28 (color filter 33), and the height y of the waveguide wall portion 29 to be shifted. z = y × tan B ………(1) SinB=n / sinA Here, B [deg] is the refraction angle of the filter component 28 (color filter 33).

[0023] Here, the incident light 22 is obliquely incident on the end side (high image height) of the pixel region 3. In contrast, in the waveguide module 26, the waveguide wall 29 is formed at a pupil-corrected position, so that the obliquely incident incident light 22 can be prevented from hitting the microlens array 18 side of the waveguide wall 29 (the portion marked with a circle 34 in FIG. 2), and the incident light 22 can be prevented from being scattered by the waveguide wall 29. In addition, in the microlens 30, a part of the incident light 22 is diffracted by the diffraction action of the microlens 30, and the diffracted incident light 22 spreads. In contrast, in the waveguide module 26, a zigzag waveguide is formed so as to extend in a direction parallel to the obliquely incident incident light 22, so that the light can be reflected at the interface between the filter component 28 and the waveguide wall 29, and the spread incident light 22 is returned to the center side of the pixel 9, and the incident light 22 can be prevented from entering other pixels 9.

[0024] The microlens array 18 has a microlens 30 for each pixel 9 on the back surface S5 side (light receiving surface side) of the color filter layer 17. Each of the microlenses 30 collects image light (incident light 22) from a subject into the photoelectric conversion unit 23 via the waveguide module 26. Furthermore, at the end side (high image height) of the pixel region 3, pupil correction is performed on each of the microlenses 30. Specifically, as shown in FIG. 2, each of the microlenses 30 is shifted toward the center side of the pixel region 3 from the waveguide module 26. Furthermore, the microlenses 30 are formed with a low profile. The height H of the microlenses 30 is, for example, preferably 300 nm or less, more preferably 200 nm or less. For example, the distance between the top and bottom surfaces of the microlenses 30 can be used as the height H. By reducing the profile of the microlenses 30, even if a part of the incident light 22 is diffracted by the diffraction effect of the microlenses 30, the entire diffracted incident light 22 can be guided into the waveguide module 26 before the diffracted incident light 22 spreads, and the incident light 22 can be prevented from entering an adjacent pixel 9.

[0025] The wiring layer 20 is formed on the surface S2 side of the substrate 2, and includes an interlayer insulating film 31 and wirings 32 stacked in multiple layers with the interlayer insulating film 31 interposed therebetween. The wiring layer 20 drives pixel transistors that configure each pixel 9 via the multiple layers of wirings 32. The support substrate 21 is formed on the surface of the wiring layer 20 opposite to the surface facing the substrate 2. The support substrate 21 is a substrate for ensuring the strength of the substrate 2 during the manufacturing stage of the solid-state imaging device 1. The support substrate 21 can be made of, for example, silicon (Si).

[0026] In the solid-state imaging device 1 having the above configuration, light is irradiated from the back surface side of the substrate 2 (the back surface S1 side of the light receiving layer 16), the irradiated light passes through the microlens 30 and the waveguide module 26, and the transmitted light is photoelectrically converted in the photoelectric conversion unit 23 to generate signal charges. Then, the generated signal charges are output as pixel signals by the vertical signal lines 11 shown in FIG. 1 formed of the wiring 32 via pixel transistors formed on the front surface S2 side of the substrate 2.

[0027] [1-3 Method for forming color filter layer] Next, a method for forming the color filter layer 17 in the solid-state imaging device 1 will be described. First, as shown in Fig. 5A, the waveguide wall portion 29 of the lower-stage waveguide 27 of the lower-stage, middle-stage, and upper-stage waveguides 27 shown in Fig. 3 is formed on the back surface S1 of the light-receiving layer 16. Then, as shown in Fig. 5B, a filter component 28 is formed in each space surrounded by the formed waveguide wall portion 29 to form the lower-stage waveguide 27. Then, as shown in Fig. 5C, the waveguide wall portion 29 of the middle-stage waveguide 27 is formed on the waveguide wall portion 29 of the lower-stage waveguide 27, shifted toward the center of the pixel region 3 from the waveguide wall portion 29 of the lower-stage waveguide 27. Then, as shown in Fig. 5D, a filter component 28 is formed in each space surrounded by the formed waveguide wall portion 29 to form the middle-stage waveguide 27. 5E, the waveguide wall portion 29 of the upper-stage waveguide 27 is formed on the waveguide wall portion 29 of the middle-stage waveguide 27, shifted toward the center of the pixel region 3 from the waveguide wall portion 29 of the middle-stage waveguide 27, and filter components 28 are formed in each space surrounded by the formed waveguide wall portions 29 to form the upper-stage waveguide 27. In this way, a color filter layer 17 having a plurality of waveguide modules 26 is obtained.

[0028] As described above, the solid-state imaging device 1 of the first embodiment is configured to include multiple stages of waveguide wall portions 29 surrounding the periphery of the color filters 33 between the color filters 33. Each of the multiple stages of waveguide wall portions 29 is formed at a position where pupil correction has been performed. Therefore, a waveguide can be formed with the color filter 33 as a core and the multiple stages of the waveguide wall portion 29 as cladding, and the incident light 22 can be suppressed from diffusing to other pixels 9 in the color filter 33, and the sensitivity of each pixel 9 can be improved. In addition, the incident light 22 is usually incident obliquely on the end side of the pixel region 3, but the obliquely incident incident light 22 can be prevented from hitting the microlens 30 side of the waveguide wall portion 29 (the part marked with a circle 34 in FIG. 2), and the incident light 22 can be prevented from being eclipsed by the waveguide wall portion 29, and the sensitivity of each pixel 9 can be further improved. In addition, it is possible to prevent the scattered light from entering other pixels 9 and causing color mixing. Therefore, it is possible to provide a solid-state imaging device 1 that can increase the sensitivity of the pixel 9 and prevent color mixing.

[0029] Moreover, the solid-state imaging device 1 of the first embodiment has a back-illuminated structure, that is, a structure in which the back surface S1 of the substrate 2 opposite to the front surface S2 of the substrate 2 on which the wiring layer 20 is formed is used as a light receiving surface and incident light 22 is incident from the back surface S1 side of the substrate 2. Therefore, the incident light 22 is incident on the photoelectric conversion unit 23 without being restricted by the wiring layer 20. Therefore, the opening of the photoelectric conversion unit 23 can be made wider, and higher sensitivity can be achieved than, for example, a front-illuminated type.

[0030] [1-4 Modifications] (1) In the first embodiment, an example in which the number of steps of the waveguide wall portion 29 is three has been shown, but other configurations can also be adopted. For example, as shown in Figs. 6 and 7, the number of steps may be less than three or more than three. Fig. 6 illustrates an example in which the waveguide wall portion 29 has two steps. Fig. 7 illustrates an example in which the waveguide wall portion 29 has four steps. By increasing the number of steps of the waveguide wall portion 29 to more than three, the waveguide formed by the entire waveguide module 26 can be tilted more greatly, which is suitable for mobile devices that require a high CRA (chie ray angle).

[0031] (2) In the first embodiment, the amount of deviation between the uppermost waveguide wall portion 29 and the lowermost waveguide wall portion 29 increases as the distance from the center of the pixel region 3 increases. However, other configurations may be adopted. For example, a configuration may be adopted in which pupil correction is not performed on the waveguide wall portion 29 in an area that is a predetermined distance or less from the center of the pixel region 3 as viewed from the microlens array 18 side, and pupil correction is performed only on the waveguide wall portion 29 in an area that is a predetermined distance or more from the center of the pixel region 3. In this case, the pupil correction may be such that the amount of deviation between the uppermost waveguide wall portion 29 and the lowermost waveguide wall portion 29 is constant regardless of the distance from the center of the pixel region 3.

[0032] (3) In the first embodiment, the height of each step of the waveguide wall portion 29 is the same, but other configurations may be adopted. For example, the height of the waveguide wall portion 29 may be different between two or more steps of the waveguide wall portion 29 among the multiple steps of the waveguide wall portion 29. Specifically, as shown in FIG. 8, the height of the waveguide wall portion 29 may be different between the steps, and further, the height of the waveguide wall portion 29 of the step on the microlens 30 side may be lower than the height of the waveguide wall portion 29 of the step on the photoelectric conversion portion 23 side. Here, for example, when the waveguide module 26 is formed, if the waveguide wall 29 and the filter component 28 are at the same height in the first-stage waveguide 27, the second-stage waveguide wall 29 is supported by both the first-stage waveguide wall 29 and the filter component 28. However, for example, if the waveguide wall 29 in the first-stage waveguide 27 becomes higher than the filter component 28, the second-stage waveguide wall 29 is not supported by the first-stage filter component 28 but is supported only by the first-stage waveguide 27, and may collapse. In contrast, by configuring the height of the waveguide wall 29 in the stage on the microlens 30 side to be lower than the waveguide wall 29 in the stage on the photoelectric conversion unit 23 side, the waveguide wall 29 is less likely to collapse, and the waveguide wall 29 can be formed relatively easily. Furthermore, for example, compared to a configuration in which the height of each step of the waveguide wall portion 29 is reduced, the number of steps of the waveguide wall portion 29 can be reduced, and manufacturing costs can be reduced.

[0033] (4) In the first embodiment, the material of each of the filter components 28 in the multiple stages is the same, but other configurations can be adopted. For example, the material of the filter components 28 may be different between two or more stages of the filter components 28 in the multiple stages. Specifically, as shown in FIG. 9, the viscosity of the material of the filter components 28 in the stage closest to the microlens 30 may be lower than the viscosity of the material of the filter components 28 in the other stages. In FIG. 9, the viscosity of the material of the filter components 28 in the first and second stages is lower than the viscosity of the material of the filter components 28 in the third stage. For example, a color filter resist resin can be adopted as the material of the filter components 28. Here, for example, when the waveguide module 26 is formed, if the surface of the filter component 28 in the first-stage waveguide 27 is uneven, the second-stage waveguide wall 29 may collapse because a part of the second-stage waveguide wall 29 is provided on the unevenness of the first-stage filter component 28. Therefore, if there is unevenness, it is necessary to polish the surface of the filter component 28 to make it flat after the filter component 28 is formed. In contrast, by configuring the color filter 33 in the stage closest to the microlens 30 to have a lower viscosity than the material of the color filter 33 in the other stages, it is possible to reduce the unevenness of the surfaces of the first and second stages of the filter component 28, and to eliminate the process of polishing the surface of the filter component 28.

[0034] (5) In the first embodiment, the width of each step of the waveguide wall portion 29 is the same, but other configurations may be adopted. For example, the width of the waveguide wall portion 29 may be different between two or more steps of the waveguide wall portion 29 among the multiple steps of the waveguide wall portion 29. Specifically, as shown in FIG. 10, the width of the waveguide wall portion 29 may be different between the steps, and further, the width of the waveguide wall portion 29 of the step on the photoelectric conversion portion 23 side may be wider than the width of the waveguide wall portion 29 of the step on the microlens 30 side. Here, for example, when the waveguide module 26 is formed, if the waveguide wall 29 and the filter component 28 are at the same height in the first-stage waveguide 27, the second-stage waveguide wall 29 is supported by both the first-stage waveguide wall 29 and the filter component 28. However, for example, if the waveguide wall 29 in the first-stage waveguide 27 becomes higher than the filter component 28, the second-stage waveguide wall 29 is not supported by the first-stage filter component 28 but is supported only by the first-stage waveguide 27, and may collapse. In contrast, by configuring the width of the waveguide wall 29 in the stage on the photoelectric conversion unit 23 side to be wider than the width of the waveguide wall 29 in the stage on the microlens 30 side, the contact area between the waveguide walls 29 can be increased, and the waveguide wall 29 is less likely to collapse, so that the waveguide wall 29 can be formed relatively easily.

[0035] (6) In the first embodiment, the amount of deviation of each stage of the waveguide wall portion 29 is the same, but other configurations may be adopted. For example, the amount of deviation of the waveguide wall portion 29 may be different between two or more stages of the waveguide wall portion 29 among the multiple stages of the waveguide wall portion 29. Specifically, as shown in FIG. 11, the amount of deviation of the waveguide wall portion 29 may be different between each stage, and the amount of deviation of the waveguide wall portion 29 of the stage on the microlens 30 side may be larger than the amount of deviation of the waveguide wall portion 29 of the stage on the photoelectric conversion portion 23 side. In FIG. 11, the magnitude relationship of the deviation amounts is in the order of deviation amount between the waveguide wall portion 29 of the third stage and the waveguide wall portion 29 of the fourth stage>deviation amount between the waveguide wall portion 29 of the second stage and the waveguide wall portion 29 of the third stage>deviation amount between the waveguide wall portion 29 of the first stage and the waveguide wall portion 29 of the second stage. Here, the incident light 22 collected by the microlens 30 is refracted at the interface between the microlens 30 and the filter component 28, so that the refraction angle is smaller than the incident angle. The refraction angle of the incident light 22 is significantly smaller as the ratio (n2 / n1) of the refractive index n1 of the microlens 30 to the refractive index n2 of the filter component 28 increases, as shown in FIG. 11. In contrast, by configuring the amount of deviation of the waveguide wall 29 of the step on the microlens 30 side to be larger than the amount of deviation of the waveguide wall 29 of the step on the photoelectric conversion unit 23 side, it is possible to prevent the obliquely incident incident light 22 from hitting the microlens 30 side of the waveguide wall 29 (the portion marked with a circle 34 in FIG. 11) and to allow the light collected by the microlens 30 to proceed to the photoelectric conversion unit 23 without hitting the waveguide wall 29 of each step. This can further improve the sensitivity of each pixel 9. Furthermore, when such a configuration is adopted, by combining a configuration in which the height of each of the multiple stages of waveguide wall portions 29 on the microlens 30 side is made lower than the height of the waveguide wall portion 29 on the photoelectric conversion unit 23 side, as shown in Figure 8, it is easy to increase the amount of deviation of the waveguide wall portion 29 on the microlens 30 side, and the waveguide wall portion 29 can be formed relatively easily.

[0036] (7) In the first embodiment, an example has been shown in which the overall height of the multi-stage waveguide wall portion 29 is the same as the height of the color filter 33, but other configurations can also be adopted. For example, a configuration in which the overall height of the multi-stage waveguide wall portion 29 is different from the height of the color filter 33 may be used. Specifically, as shown in FIG. 12, the overall height of the multi-stage waveguide wall portion 29 may be higher than the height of the color filter 33. In FIG. 12, the upper end side of the fifth stage waveguide wall portion 29 protrudes from the color filter 33 and is located between the microlenses 30. Here, for example, if the total height of the multi-stage waveguide wall portion 29 is made lower than the height of the color filter 33, the top-stage waveguide wall portion 29 is less likely to fall over, so that the waveguide wall portion 29 can be formed relatively easily, and the process difficulty can be reduced. However, since the distance between the microlens 30 and the waveguide wall portion 29 is long, it is not possible to guide all of the incident light 22 diffracted and spread by the microlens 30 into the waveguide module 26, and the waveguide effect may be weakened. In addition, since a part of the incident light 22 passes through the color filter 33 of the adjacent pixel 9, the incident light 22 may be weakened, and the sensitivity of each pixel 9 may be reduced. In contrast, by configuring the total height of the multi-stage waveguide wall portion 29 to be higher than the height of the color filter 33, it is possible to guide all of the diffracted incident light 22 into the waveguide module 26 before the diffracted incident light 22 spreads, and the waveguide effect can be strengthened. Furthermore, since the incident light 22 does not pass through the color filter 33 of the adjacent pixel 9, the sensitivity of each pixel 9 can be improved.

[0037] 2. Second embodiment: Application to electronic devices The technology according to the present disclosure (the present technology) may be applied to various electronic devices such as imaging devices such as digital still cameras and digital video cameras, mobile phones with imaging functions, or other devices with imaging functions. FIG. 13 is a diagram showing an example of a schematic configuration of an electronic device (for example, a camera) to which the technology according to the present disclosure (the present technology) can be applied. As shown in FIG. 13, the electronic device 100 includes a solid-state imaging device 101, an optical lens 102, a shutter device 103, a drive circuit 104, and a signal processing circuit 105.

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

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

[0040] The present technology can also be configured as follows. (1) A plurality of microlenses for collecting incident light; A plurality of color filters that transmit light of specific wavelengths contained in the condensed incident light; a plurality of photoelectric conversion units to which light of a specific wavelength that has passed through the color filter is incident; a plurality of stages of waveguide walls disposed between the color filters and surrounding the periphery of the color filters; Each of the plurality of stages of the waveguide wall portions is formed at a position where pupil correction is performed. Solid-state imaging device. (2) The waveguide wall includes a low refractive index material having a lower refractive index than the color filter. The solid-state imaging device according to (1) above. (3) The heights of the waveguide wall portions are different between two or more stages of the waveguide wall portions among the plurality of stages of the waveguide wall portions. The solid-state imaging device according to (1) or (2). (4) The height of the waveguide wall portion of the step on the microlens side is lower than the height of the waveguide wall portion of the step on the photoelectric conversion portion side. The solid-state imaging device according to (3) above. (5) The color filter includes a plurality of filter components, The materials of the filter constituent members are different between two or more stages of the filter constituent members among the multiple stages of the filter constituent members. A solid-state imaging device according to any one of (1) to (4). (6) The viscosity of the material of the color filter in the step closest to the microlens is lower than the viscosity of the material of the color filter in the other steps. The solid-state imaging device according to (5) above. (7) The widths of the waveguide wall portions are different between two or more stages of the waveguide wall portions among the plurality of stages of the waveguide wall portions. A solid-state imaging device according to any one of (1) to (6). In other words, (7) is that "the width of the waveguide wall portion in a cross section perpendicular to the back surface S3 (light receiving surface) of the substrate 2 in a direction parallel to the back surface S3 (light receiving surface) of the substrate 2 is different between two or more stages of the waveguide wall portions among the multiple stages of the waveguide wall portions. It can also be said that the solid-state imaging device is the one described in any one of (1) to (6) above. (8) The width of the waveguide wall portion of the step on the photoelectric conversion unit side is wider than the width of the waveguide wall portion of the step on the microlens side. The solid-state imaging device according to (7) above. (9) The amount of deviation of the waveguide wall portion is different between two or more stages of the waveguide wall portion among the plurality of stages of the waveguide wall portion. A solid-state imaging device according to any one of (1) to (8). (10) The amount of deviation of the waveguide wall portion of the step on the microlens side is larger than the amount of deviation of the waveguide wall portion of the step on the photoelectric conversion unit side. The solid-state imaging device according to (9) above. (11) The total height of the multiple stages of the waveguide wall portion is different from the height of the color filter. The solid-state imaging device according to any one of (1) to (10) above. (12) The total height of the multiple stages of the waveguide wall portion is greater than the height of the color filter. The solid-state imaging device according to (11) above. (13) The photoelectric conversion unit has a back-illuminated structure. A solid-state imaging device according to any one of (1) to (12) above. (14) The height of the microlenses is 300 nm or less. A solid-state imaging device according to any one of (1) to (13) above. (15) a solid-state imaging device including a plurality of microlenses that collect incident light, a plurality of color filters that transmit light of a specific wavelength contained in the collected incident light, a plurality of photoelectric conversion units to which the light of the specific wavelength that has transmitted through the color filters is incident, and a plurality of stages of waveguide wall portions that are disposed between the color filters and surround the periphery of the color filters, each of the plurality of stages of waveguide wall portions being formed at a position where pupil correction has been performed; an optical lens that forms an image of image light from a subject on an imaging surface of the solid-state imaging device; a signal processing circuit for performing signal processing on a signal output from the solid-state imaging device; electronic equipment. [Explanation of symbols]

[0041] 1...solid-state imaging device, 2...substrate, 3...pixel region, 4...vertical drive circuit, 5...column signal processing circuit, 6...horizontal drive circuit, 7...output circuit, 8...control circuit, 9...pixel, 10...pixel drive wiring, 11...vertical signal line, 12...horizontal signal line, 13...insulating film, 14...light-shielding film, 15...planarizing film, 16...light-receiving layer, 17...color filter layer, 18...microlens array, 19...light-collecting layer, 20...wiring layer, 21...support substrate, 22...incident Light, 23...photoelectric conversion section, 24...pixel separation section, 25...trench section, 26...waveguide module, 27...waveguide, 28...filter component, 29...waveguide wall section, 30...microlens, 31...interlayer insulating film, 32...wiring, 33...color filter, 34...circle, 100...electronic device, 101...solid-state imaging device, 102...optical lens, 103...shutter device, 104...drive circuit, 105...signal processing circuit, 106...incident light

Claims

1. A plurality of microlenses for collecting incident light; A plurality of color filters that transmit light of specific wavelengths contained in the condensed incident light; a plurality of photoelectric conversion units to which light of a specific wavelength that has passed through the color filter is incident; a plurality of stages of waveguide walls disposed between the color filters and surrounding the periphery of the color filters; Each of the plurality of stages of the waveguide wall portions is formed at a position where pupil correction is performed. Solid-state imaging device.

2. The waveguide wall includes a low refractive index material having a lower refractive index than the color filter. The solid-state imaging device according to claim 1 .

3. The heights of the waveguide wall portions are different between two or more stages of the waveguide wall portions among the plurality of stages of the waveguide wall portions. The solid-state imaging device according to claim 1 .

4. The height of the waveguide wall portion of the step on the microlens side is lower than the height of the waveguide wall portion of the step on the photoelectric conversion portion side. The solid-state imaging device according to claim 3 .

5. The color filter includes a plurality of filter components, The materials of the filter constituent members are different between two or more stages of the filter constituent members among the multiple stages of the filter constituent members. The solid-state imaging device according to claim 1 .

6. The viscosity of the material of the filter component of the stage closest to the microlens is lower than the viscosity of the material of the filter component of the other stages. The solid-state imaging device according to claim 5 .

7. The widths of the waveguide wall portions are different between two or more stages of the waveguide wall portions among the plurality of stages of the waveguide wall portions. The solid-state imaging device according to claim 1 .

8. The width of the waveguide wall portion of the step on the photoelectric conversion unit side is wider than the width of the waveguide wall portion of the step on the microlens side. The solid-state imaging device according to claim 7 .

9. The amount of deviation of the waveguide wall portion is different between two or more stages of the waveguide wall portion among the plurality of stages of the waveguide wall portion. The solid-state imaging device according to claim 1 .

10. The amount of deviation of the waveguide wall portion of the step on the microlens side is larger than the amount of deviation of the waveguide wall portion of the step on the photoelectric conversion unit side. The solid-state imaging device according to claim 9 .

11. The total height of the multiple stages of the waveguide wall portion is different from the height of the color filter. The solid-state imaging device according to claim 1 .

12. The total height of the multiple stages of the waveguide wall portion is greater than the height of the color filter. The solid-state imaging device according to claim 11.

13. The photoelectric conversion unit has a back-illuminated structure. The solid-state imaging device according to claim 1 .

14. The height of the microlenses is 300 nm or less. The solid-state imaging device according to claim 1 .

15. a solid-state imaging device including a plurality of microlenses that collect incident light, a plurality of color filters that transmit light of a specific wavelength contained in the collected incident light, a plurality of photoelectric conversion units to which the light of the specific wavelength that has transmitted through the color filters is incident, and a plurality of stages of waveguide wall portions that are disposed between the color filters and surround the periphery of the color filters, each of the plurality of stages of waveguide wall portions being formed at a position where pupil correction has been performed; an optical lens that forms an image of image light from a subject on an imaging surface of the solid-state imaging device; a signal processing circuit for performing signal processing on a signal output from the solid-state imaging device; electronic equipment.

Images