solid-state imaging device

Abstract

In a solid-state imaging device, the reflectance of the Si substrate surface is reduced while suppressing increases in dark current and light scattering. [Solution] The solid-state imaging device includes a plurality of pixels formed on a silicon substrate. Each pixel includes a photoelectric conversion region formed on the surface of the silicon substrate, a concave-convex pattern including concave and convex portions provided on the surface of the silicon substrate in the photoelectric conversion region, a first material film covering the side surfaces of the concave-convex pattern, the bottom surfaces of the concave portions, and the top surfaces of the convex portions, and leaving voids in the concave portions, and a second material film filling the voids. The refractive index of the first material film is higher than the refractive index of the second material film, and the refractive indexes of the first material film and the second material film are both 1.7 or less.

Description

[Technical Field]

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

[0002] Image sensors (solid-state imaging devices) are used to capture images in various devices such as smartphones. To improve the light-receiving sensitivity of solid-state imaging devices, the reflectance of the surface of the silicon substrate used as the semiconductor substrate is reduced and the quantum efficiency is increased.

[0003] To achieve this, it is known to form a concave-convex pattern on the surface of a Si substrate, which artificially reduces the refractive index near the surface of the Si substrate, thereby reducing the reflectance (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-061576 Summary of the Invention [Problem to be solved by the invention]

[0005] Forming a concave-convex pattern on the surface of a Si substrate can reduce reflectance, but it also destabilizes the charge state on the Si substrate surface, increasing dark current. Furthermore, light that passes through the concave-convex pattern is prone to scattering due to diffraction and / or refraction. This scattered light can penetrate adjacent pixels, causing color mixing and degrading the image quality of captured images.

[0006] In response to the above, an object of the present disclosure is to realize a solid-state imaging device that can reduce the reflectance at the surface of the Si substrate while suppressing increases in dark current and light scattering. [Means for solving the problem]

[0007] The solid-state imaging device of the present disclosure includes a plurality of pixels formed on a silicon substrate. Each pixel includes a photoelectric conversion region formed on the surface of the silicon substrate, a concave-convex pattern including concave and convex portions provided on the surface of the silicon substrate in the photoelectric conversion region, a first material film covering the side surfaces of the concave-convex pattern, the bottom surfaces of the concave portions, and the top surfaces of the convex portions, and leaving voids in the concave portions, and a second material film filling the voids. The refractive index of the first material film is higher than the refractive index of the second material film, and the refractive indexes of the first material film and the second material film are both 1.7 or less. [Effects of the Invention]

[0008] According to the solid-state imaging values ​​of the present disclosure, the reflectance on the surface of the Si substrate can be reduced while suppressing increases in dark current and light scattering. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of a solid-state imaging device according to the present disclosure. [Figure 2] FIG. 2 is a schematic plan view showing a concave-convex pattern portion in the solid-state imaging device of the present disclosure. [Figure 3] FIG. 3 is a schematic cross-sectional view showing an enlarged view of the vicinity of a concave-convex pattern portion in the solid-state imaging device of the present disclosure. [Figure 4] FIG. 4 is a schematic cross-sectional view of a solid-state imaging device of a comparative example. [Figure 5] FIG. 5 is a diagram showing a case where the width of the recess is relatively large in the solid-state imaging device of the present disclosure. [Figure 6] FIG. 6 is a diagram showing a case where the width of the recess is relatively small in the solid-state imaging device of the present disclosure. [Figure 7] FIG. 7 is a schematic plan view showing another example of a concave-convex pattern portion in a solid-state imaging device according to the present disclosure. [Figure 8] FIG. 8 is a diagram showing the reflectance versus wavelength of incident light for the solid-state imaging device of the present disclosure and the solid-state imaging device of the comparative example. [Figure 9]FIG. 9 is a diagram showing the relationship between the recess area ratio and the reflectance of the antireflection layer 22 for light of different wavelengths. [Figure 10] FIG. 10 is a diagram illustrating an example of the recessed portion area ratio corresponding to each color when color filters are arranged in a Bayer array in the solid-state imaging device of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The following description is for illustrative purposes only and is not intended to be limiting. Furthermore, modifications can be made as appropriate within the scope of the present disclosure.

[0011] FIG. 1 is a schematic cross-sectional view of a solid-state imaging device 20 (image sensor) according to this embodiment, showing an area corresponding to one of a plurality of pixels.

[0012] The solid-state imaging device 20 is a back-illuminated solid-state imaging device configured using a silicon (Si) substrate 1. The silicon substrate 1 has a photodiode structure in which a p-type layer 1a is formed on an n-type layer, thereby functioning as a photoelectric conversion region that converts incident light into electric charges.

[0013] A concave-convex pattern 2 including convex portions 8 and concave portions 10 is provided on the surface of a silicon substrate 1. A fixed charge film 3, which is a first material film, is formed on the surface of the concave-convex pattern 2, and an oxide film 4 (silicon oxide film), which is a second material film, is formed thereon. More specifically, the fixed charge film 3 is formed so as to cover the side surfaces of the concave-convex pattern 2, the bottom surfaces of the concave portions 10, and the top surfaces of the convex portions 8 with the same thickness. Furthermore, the fixed charge film 3 does not completely fill the concave portions 10, leaving voids. An oxide film 4 is formed on the fixed charge film 3 so as to fill the voids.

[0014] In the manufacturing process of the solid-state imaging device 20, the silicon substrate 1 is processed by etching or the like. During this process, the surface of the silicon substrate 1 is damaged, and the state of the interface with the film formed thereon becomes unstable. In response to this, by forming a film having a fixed charge, such as Al2O3, on the surface of the silicon substrate 1, the state of the interface can be stabilized.

[0015] FIG. 2 shows a plan view of the concave-convex pattern portion 2. In this embodiment, each convex portion 8 is an independent square and is separated by a concave portion 10. The convex portions 8 have a width W and are arranged vertically and horizontally. The arrangement period P (the sum of the width W and the distance between adjacent convex portions 8) is the same both vertically and horizontally. In the example of FIG. 2, the period P is slightly more than twice the width W. Furthermore, the rows of convex portions 8 are arranged so that the positions of the convex portions 8 do not overlap with those of adjacent rows.

[0016] It is most preferable that the side surfaces of the protrusions 8 are perpendicular to the surface of the silicon substrate 1 (the bottom surfaces of the recesses 10). However, perpendicularity is not essential to achieve the effects of this embodiment. In other words, the side surfaces of the protrusions 8 may be inclined to form a tapered shape. For example, the angle of the side surfaces of the protrusions 8 with respect to a plane perpendicular to the surface of the silicon substrate 1 is preferably 30° or less, and more preferably 15° or less.

[0017] Next, a color filter 5 and a microlens portion 6 are formed on the oxide film 4. Furthermore, a light-shielding film 7 is formed in the oxide film 4 between adjacent pixels.

[0018] Light 21 incident on the solid-state imaging device 20 passes through the microlens section 6, color filter 5, oxide film 4, and concave-convex pattern section 2, enters the silicon substrate 1, and undergoes photoelectric conversion. If incident light leaks into adjacent pixels, color mixing occurs, so a light-shielding film 7 is provided to suppress this. The light-shielding film 7 is made of a material with high light-shielding properties, such as tungsten (W). The color filter 5 allows light of a desired wavelength band to enter depending on the pixel in order to capture a color image. Therefore, a color filter 5 is not provided in the case of a monochrome image sensor.

[0019] 3 is a diagram showing the vicinity of the concave-convex pattern portion 2 in FIG. In a solid-state imaging device 20 of this embodiment, the concave-convex pattern portion 2 is provided on the surface portion of a silicon substrate 1, and a fixed charge film 3 and an oxide film 4 are embedded in the recesses 10. This reduces the effective refractive index of the region surrounded by the dashed line, causing it to function as an anti-reflection layer 22.

[0020] In this regard, Fig. 4 shows a solid-state imaging device 20a of a comparative example. In the solid-state imaging device 20a, the surface portion of the silicon substrate 1 is flat. A fixed charge film 3 is formed so as to cover the upper surface of the flat silicon substrate 1, and an anti-reflection film 9 is further formed thereon. As with the solid-state imaging device 20 of this embodiment, an oxide film 4, a color filter 5, and a microlens portion 6 are formed on the anti-reflection film 9.

[0021] In the case of the solid-state imaging device 20a of the comparative example, Si3N4 (refractive index 1.94 to 2.05), Ta2O5 (refractive index 2.17), etc. are often used for the antireflection film 9. The refractive index is a value at a wavelength of 450 nm.

[0022] However, because silicon has a high refractive index in the blue to green light range (especially in the blue light range), the refractive index of the anti-reflection film 9 becomes too low, resulting in difficulty in suppressing reflection. For example, when the incident light is blue light (wavelength 450 nm), the refractive index of the silicon substrate 1 (Si) is 4.67, whereas it is desirable to provide an anti-reflection film 9 with a refractive index of 2.74 or higher. However, no suitable film-forming material for semiconductors is known. In addition, in the case of the solid-state imaging device 20a of the comparative example, a fixed charge film 3 with a low refractive index is formed under the anti-reflection film 9, further reducing the anti-reflection effect.

[0023] In contrast, in the solid-state imaging device 20 of this embodiment, a concave-convex pattern portion 2 is provided on the surface portion of the silicon substrate 1, and a fixed charge film 3 and an oxide film 4 having a refractive index smaller than that of the silicon substrate 1 are embedded in the recesses 10, thereby realizing an anti-reflection layer 22 with a reduced effective refractive index.

[0024] The anti-reflection layer 22 is most effective in reducing the reflectance when its effective refractive index is the geometric mean of the refractive indices of the layers above and below it, that is, the refractive index of the silicon substrate 1 and the refractive index of the oxide film 4. Therefore, when the refractive index of Si constituting the silicon substrate 1 is set to n si The refractive index of the silicon oxide film constituting the oxide film 4 is n SiO In this case, the target value of the effective refractive index of the antireflection layer 22 can be expressed by the following formula (1).

[0025] The target value of the effective refractive index of the anti-reflection layer 22 is ≒√(n si ×n SiO ) ……(1)

[0026] From formula (1), in order to bring the reflectance in the visible light region (wavelengths of about 400 nm to 650 nm) close to zero, it is preferable that the effective refractive index of the antireflection layer 22 is about 2.37 to 2.8.

[0027] This is achieved by making the refractive index of the material filled in the recess 10 smaller than the target value of the effective refractive index, and it is particularly desirable to use a material with a refractive index of 1.7 or less. Specific examples of such materials include Al2O3, which has a refractive index of 1.6, and SiO2, which has a refractive index of 1.46.

[0028] The effective refractive index of the antireflection layer 22 is calculated as an average value of the refractive indexes of the convex portions 8 and the concave portions 10, weighted by the volume ratio of the convex portions 8 and the concave portions 10. In other words, it is a value obtained by adding the product of the refractive index of the convex portions 8 and the volume ratio of the convex portions 8 to the product of the refractive index of the concave portions 10 and the volume ratio of the concave portions 10. For example, if the volumes of the convex portions 8 and the concave portions 10 occupy 40% and 60%, respectively, and the refractive index of the convex portions 8 is 4.67 and the refractive index of the concave portions 10 is 1.47, the effective refractive index of the antireflection layer 22 is calculated as 4.67×0.4+1.47×0.6=2.75.

[0029] Therefore, the desired recess area ratio is determined from the material of the protrusions 8 and the material filling the recesses 10 (refractive index), as well as the target value of the effective refractive index.

[0030] Furthermore, it is desirable to design the concave-convex pattern portion 2 in terms of dark current in addition to the characteristics as the antireflection layer 22.

[0031] When the concave-convex pattern 2 is formed on the surface of the silicon substrate 1, the charge state on the silicon surface becomes unstable, which may increase dark current. Dark current causes deterioration of image quality, especially when capturing dark images, causing the image to appear white and blurred.

[0032] The dark current increases or decreases in proportion to the surface area of ​​the recesses 10. Therefore, by reducing the surface area of ​​the recesses 10, the increase in dark current can be suppressed. To achieve this, it is preferable to reduce the refractive index of the material filled in the recesses 10. By filling the recesses 10 with a material with a lower refractive index, the volume ratio of the recesses 10 required to achieve an anti-reflection layer 22 with a desired refractive index can be reduced. As a result, the surface area of ​​the recesses 10 is reduced, thereby suppressing the increase in dark current.

[0033] Furthermore, filling the recesses 10 with a material having a low refractive index is also effective in reducing color mixing between pixels. One of the causes of color mixing is scattering of light when it passes through the concave-convex pattern portion 2. In order to suppress scattering of transmitted light, it is effective to reduce the period P (see FIGS. 2 and 3) of the concave-convex pattern portion 2. More specifically, the effective period P taking the refractive index into consideration is E By making the wavelength smaller than the wavelength of the transmitted light, it is possible to suppress the diffraction of light and the scattering of light, thereby reducing color mixing.

[0034] Effective period P taking into account the refractive index E is calculated by calculating the product of the dimensions and refractive index of each of the protrusions 8 and the recesses 10 and summing them. As an example, when the width of the protrusions 8 made of Si with a refractive index of 4.67 is 75 nm and the width of the recesses 10 filled with SiO2 with a refractive index of 1.47 is 95 nm, the effective period P E = 4.67 × 75 nm + 1.47 × 95 nm = 490 nm.

[0035] Therefore, if the dimensions (and further the period P) of the convex portion 8 and the concave portion 10 are the same, the lower the refractive index of the material filled in the concave portion 10, the shorter the effective period P E becomes smaller, scattering of incident light and therefore color mixing are suppressed.

[0036] As described above, the desirable recess area ratio is determined from the target value of the effective refractive index of the antireflection layer 22. If the recess area ratio is the same, the period P becomes smaller by reducing the width W of the protrusions 8, and the effective period P E However, since the minimum width of the protrusions 8 that can be formed depends on the processing means, it is difficult to arbitrarily reduce the width W and the period P. As an example, when an immersion ArF exposure tool is used, the minimum processable width is thought to be about 75 nm. However, the technology of the present disclosure is not limited to this example dimension.

[0037] Furthermore, in the solid-state imaging device 20 of this embodiment, a fixed charge film 3 is formed to cover the surface of the concave-convex pattern portion 2. By providing the fixed charge film 3, it is possible to stabilize the charge on the surface of the silicon substrate 1 and suppress dark current. Since the fixed charge film 3 also fills part of the recess 10, it is desirable for the refractive index to be low. Therefore, it is desirable to use Al2O3, which has a refractive index of 1.6, as the material for the fixed charge film 3. Al2O3 is one of the materials with an extremely low refractive index for a fixed charge film.

[0038] However, in order for the fixed charge film 3 to exert the above-mentioned effects, it is preferable that the film has a predetermined thickness, for example, a film thickness of 15 nm or more. On the other hand, it is preferable that the material filling the recesses 10 contains a high proportion of SiO2, which has an even lower refractive index than Al2O3. From this viewpoint, there is an upper limit to the preferable film thickness of the fixed charge film 3, for example, it is preferable that it is 40 nm or less.

[0039] As described above, the fixed charge film 3 is provided so as not to completely fill the recess 10, leaving a void in the recess 10. An oxide film 4 made of SiO2 with a refractive index of 1.46 is formed on the fixed charge film 3 so as to fill the void.

[0040] In this way, when the fixed charge film 3 is formed on the silicon substrate 1 and then the oxide film 4 is formed on top of that, the refractive index gradually decreases. Therefore, the difference in refractive index at each interface becomes smaller, and the anti-reflection effect becomes more pronounced.

[0041] To form the concave-convex pattern portion 2, for example, a resist pattern is formed on the surface of the silicon substrate 1 using exposure processing with an immersion ArF exposure machine, and then dry etching is performed. As a result, the surface of the silicon substrate 1 is etched into a predetermined pattern to form concave portions 10, and the remaining portions become convex portions 8.

[0042] In this embodiment, the pattern period P is 170 nm, and the width of the convex portions 8 (one side of a square) is 75 nm. The height of the convex portions 8 is 55 nm. The height of the convex portions 8 (in other words, the depth of the concave portions 10) is preferably 40 nm or more from the viewpoint of ensuring the anti-reflection effect in the green to red wavelength region. Also, from the viewpoint of clearly forming the shape of the convex portions 8, it is preferably 40 nm or more. On the other hand, from the viewpoint of ensuring the anti-reflection effect in the blue region and suppressing the generation of diffracted light, the height of the convex portions 8 is preferably 70 nm or less.

[0043] In this embodiment, the area ratio of the etched recesses 10 is approximately 63%. That is, in the plan view of FIG. 2, the ratio of the area occupied by the recesses 10 to the total area of ​​the protrusions and recesses 10 is approximately 63%.

[0044] In this embodiment, by using Al2O3 and SiO2, which have low refractive indices, as the materials to be filled into the recesses 10, it is possible to reduce the recess area ratio to 63% while maintaining a desirable effective refractive index of the antireflection layer 22. In contrast, when other materials are used to fill the recesses 10, examples of recess area ratios required to maintain a desirable effective refractive index of the antireflection layer 22 are as follows: Al2O3 only: 67% HfO+SiO2:67% ZrO+SiO2:70%

[0045] In this way, by using a material with a low refractive index to fill the recesses 10, the area ratio of the recesses 10 formed by etching the silicon substrate 1 can be reduced, and the increase in dark current associated with the formation of the uneven pattern portion 2 can be suppressed.

[0046] Next, the optical effect will be further explained.

[0047] 5 and 6 are diagrams comparing the pitch P of the concave-convex pattern 2 and the state of scattering of light after passing through the concave-convex pattern 2 in the solid-state imaging device 20 of this embodiment.

[0048] In FIG. 5, the width W of the convex portion 8 is set to 100 nm. If the concave portion area ratio is set to 63%, the period P is determined to be 227 nm. In this case, incident light 21 that has passed through the concave-convex pattern portion 2 begins to scatter due to diffraction. Scattering due to diffraction is more likely to occur as the width W and period P increase. Light scattering can cause color mixing in adjacent pixels, so it is desirable to suppress it.

[0049] 1 to 3, that is, the period P is 170 nm and the width W is 75 nm. In this case, scattering due to diffraction of incident light 21 is unlikely to occur even when it passes through the concave-convex pattern portion 2. By setting the period P and the width W in this way, scattering of incident light 21 can be suppressed, and as a result, color mixing can be suppressed.

[0050] To suppress scattering due to diffraction, it is desirable to set the period P to 200 nm or less. In this case, if the area of ​​the recesses is 63%, the width W will be 90 nm. From this perspective, it is preferable that the width W be 90 nm or less. However, even if the period P exceeds 200 nm, the antireflection layer 22 can still achieve the effect of suppressing reflection of incident light.

[0051] In the above, the shape of the protrusions 8 in the plan view is a square, as shown in Fig. 2. In this case, the protrusions 8 are arranged most densely in both the horizontal and vertical directions in Fig. 2.

[0052] 7 shows another example in which the protrusions 8 are regular octagons when viewed from a direction perpendicular to the silicon substrate, i.e., in a plan view. In this way, the intervals between the protrusions 8 can be reduced in the diagonal direction as well, allowing them to be densely arranged.

[0053] 2 and 7, when the area ratio of the recesses 10 is set to the same 63%, the effect of suppressing reflectance by the recessed / protruding pattern portion 2 is the same. However, in FIG. 7, the intervals between the protrusions 8 can be made narrower, so the effect of suppressing light scattering is greater.

[0054] Next, Fig. 8 shows the results of measuring the reflectance versus wavelength of incident light for the solid-state imaging device 20 of this embodiment and the solid-state imaging device 20a (Fig. 4) of the comparative example. Note that both are monochrome imaging devices that do not include a color filter 5. In addition, for the comparative example, Si3N4 with a refractive index of 1.95 was used for the anti-reflection film 9.

[0055] 8, the reflectance of the example is suppressed more than that of the comparative example in most wavelength bands. In particular, the reflectance is suppressed significantly from the blue region of 400 nm wavelength to the yellow region of 570 nm wavelength.

[0056] Furthermore, although an image pickup device for monochrome images is shown as an example in FIG. 8, in the case of an image pickup device for color images that includes a color filter 5, the area of ​​the recesses can be changed and optimized for each color.

[0057] 9 shows the relationship between the recess area ratio and the reflectance of the antireflection layer 22 for light of different wavelengths. More specifically, the relationship is shown for blue light (wavelength 450 nm, shown by the dashed line), green light (wavelength 530 nm, shown by the dotted line), and red light (wavelength 600 nm, shown by the solid line).

[0058] 9, the desirable concave portion area ratio for reducing reflectance varies depending on the wavelength. The area ratio of the concave portions 10 that results in the lowest (i.e., optimal) reflectance and the range of the area ratio that results in the reflectance being lower than that of the solid-state imaging device 20a of the comparative example (i.e., improved) are as follows: Blue: Optimal at 65%, improved at 60% or more and 70% or less Green: Optimal at 63%, improved at 58% or more and 68% or less Red: Optimal at 62%, improved at 57% or more and 67% or less As such, the longer the wavelength of light, the lower the desirable area ratio. For visible light, it can be said that reflectance is improved when the area ratio is 57% or more and 70% or less. In addition, when the pixel includes a first pixel for receiving light of a first wavelength and a second pixel for receiving light of a wavelength longer than the first wavelength, and is not limited to blue, green, and red, it is preferable that the ratio of the area occupied by the recesses to the uneven pattern in the first pixel is greater than the ratio of the area occupied by the recesses to the uneven pattern in the second pixel.

[0059] In the case of a solid-state imaging device 20 for color images, the reflectance of each color can be optimized (quantum efficiency can be maximized) by setting the above-mentioned optimum recessed area ratio in the photoelectric conversion region corresponding to each color. For example, in the example of Fig. 10, when blue (B), green (G), and red (R) color filters are arranged in a Bayer array, the recessed area ratio of the concave-convex pattern portion 2 provided on the silicon substrate 1 is set to the above-mentioned optimum value.

[0060] Although the above description has been given taking a back-illuminated solid-state imaging device as an example, the same effect can be obtained with a front-illuminated solid-state imaging device.

[0061] As described above, the solid-state imaging device of the present disclosure can reduce the reflectance on the surface of the silicon substrate 1 and suppress an increase in dark current. Furthermore, the period P of the concave-convex pattern portion 2 provided on the silicon substrate 1 can be reduced, thereby suppressing the occurrence of diffracted light and scattered light and suppressing color mixing with adjacent pixels. Therefore, the quality of the captured image can be improved.

[0062] The above-described embodiments may be modified in form and detail without departing from the spirit of the claims. Furthermore, the contents of the embodiments may be combined and substituted as appropriate as long as the functions of the subject matter of the present disclosure are not impaired. [Industrial Applicability]

[0063] The solid-state imaging device of the present disclosure is useful as an imaging device in various cameras, portable devices, and the like. [Explanation of symbols]

[0064] 1. Silicon substrate 1a p-type layer 2 Concave and convex pattern part 3 Fixed charge membrane 4. Oxide film 5 Color Filters 6 Microlens section 7 Light-shielding film 8 Convex part 9 Anti-reflection coating 10 recess 20 Solid-state imaging device 20a Solid-state imaging device (comparison example) 21 Incident light 22 Anti-reflection layer

Claims

1. In a solid-state imaging device having a plurality of pixels formed on a silicon substrate, Each of the pixels is a photoelectric conversion region formed on a surface portion of the silicon substrate; a concave-convex pattern including concave portions and convex portions provided on the surface of the silicon substrate in the photoelectric conversion region; a first material film that covers the side surfaces of the concave-convex pattern, the bottom surfaces of the concave portions, and the top surfaces of the convex portions, and leaves voids in the concave portions; a second material film filling the voids; the refractive index of the first material film is greater than the refractive index of the second material film; the refractive index of the first material film and the refractive index of the second material film are both 1.7 or less; In the concave-convex pattern, the convex portions are arranged independently and vertically and horizontally, separated by the concave portions, The rows of the protrusions are arranged so that the positions of the protrusions do not overlap with adjacent rows of the protrusions, the pixels are pixels for receiving visible light, and the ratio of the area occupied by the recesses to the area of ​​the concave-convex pattern is 57% or more and 70% or less; Or, the pixels include blue pixels for receiving blue light, green pixels for receiving green light, and red pixels for receiving red light, and a ratio of an area occupied by the recesses to the uneven pattern is 60% or more and 70% or less in the blue pixels, 58% or more and 68% or less in the green pixels, and 57% or more and 67% or less in the red pixels; A solid-state imaging device, wherein an effective period of the concave-convex pattern portion, taking into consideration a refractive index, is smaller than the wavelength of light passing through the concave-convex pattern portion.

2. In claim 1, The solid-state imaging device is characterized in that the first material film covers the side surfaces of the concave-convex pattern, the bottom surfaces of the concave portions, and the top surfaces of the convex portions with the same thickness.

3. In claim 1, The solid-state imaging device is characterized in that the first material film is a fixed charge film.

4. In claim 3, A solid-state imaging device, wherein the fixed charge film has a thickness of 15 nm or more.

5. In claim 3, The fixed charge film is made of Al ２ O ３ A solid-state imaging device comprising:

6. In claim 1, A solid-state imaging device, wherein the ratio of the area occupied by the recesses to the area of ​​the concave / convex pattern is 57% or more and 70% or less.

7. In claim 1, A solid-state imaging device, wherein the width of the convex portion is 90 nm or less.

8. In claim 1, A solid-state imaging device, wherein the depth of the recesses in the concave-convex pattern is 40 nm or more and 70 nm or less.

9. In claim 1, the pixels include a first pixel for receiving light of a first wavelength; a second pixel for receiving light having a wavelength longer than the first wavelength; a ratio of an area occupied by the recesses to the uneven pattern in the first pixel to a ratio of an area occupied by the recesses to the uneven pattern in the second pixel;

10. In claim 1, The solid-state imaging device is characterized in that the convex portion has an octagonal shape when viewed from a direction perpendicular to the silicon substrate, and has a width of 90 nm or less.

11. In claim 1, A solid-state imaging device, wherein the side surface of the convex portion is at an angle of 30° or less with respect to a plane perpendicular to the surface of the silicon substrate.

Images