Solid-state imaging device

Abstract

In solid-state imaging, the reflectivity of the Si substrate surface is reduced while suppressing increases in dark current and light scattering. [Solution] The solid-state imaging device comprises a plurality of pixels formed on a silicon substrate. Each pixel comprises a photoelectric conversion region formed on the surface of the silicon substrate, an uneven pattern including recesses and protrusions provided on the surface of the silicon substrate in the photoelectric conversion region, a first material film covering the sides of the uneven pattern, the bottom of the recesses and the top of the protrusions while leaving voids in the recesses, and a second material film filling the voids. The refractive index of the first material film is greater than that of the second material film, and the refractive indices of both the first and second material films are 1.7 or less.

Description

[Technical Field]

[0001] This 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 reflectivity of the surface of the Si substrate used as the semiconductor substrate is reduced, thereby increasing the quantum efficiency.

[0003] To achieve this, it is known that an uneven pattern is formed on the surface of the Si substrate. The uneven pattern can artificially lower the refractive index near the surface of the Si substrate, thereby reducing the reflectivity (Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-061576 [Overview of the project] [Problems that the invention aims to solve]

[0005] When a textured pattern is formed on the surface of a Si substrate, reflectivity can be reduced, but the charge state on the Si substrate surface becomes unstable, increasing the dark current. Furthermore, light transmitted through the textured pattern is easily scattered due to diffraction and / or refraction. This scattered light penetrates adjacent pixels, causing color mixing and degrading the image quality of the captured image.

[0006] In relation to the above, the objective of this disclosure is to realize a solid-state imaging device that can reduce reflectivity on the surface of a Si substrate while suppressing an increase in dark current and light scattering. [Means for solving the problem]

[0007] The solid-state imaging device of this disclosure comprises a plurality of pixels formed on a silicon substrate. Each pixel comprises a photoelectric conversion region formed on the surface of the silicon substrate, an uneven pattern including recesses and protrusions provided on the surface of the silicon substrate in the photoelectric conversion region, a first material film covering the sides of the uneven pattern, the bottom surface of the recesses and the top surface of the protrusions while leaving voids in the recesses, and 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, and the refractive indices of both the first and second material films are 1.7 or less. [Effects of the Invention]

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

[0009] [Figure 1] Figure 1 is a schematic cross-sectional view of the solid-state imaging device of this disclosure. [Figure 2] Figure 2 is a schematic plan view showing the uneven pattern portion of the solid-state imaging device of this disclosure. [Figure 3] Figure 3 is a schematic cross-sectional view showing an enlarged view of the area near the uneven pattern portion of the solid-state imaging device of this disclosure. [Figure 4] Figure 4 is a schematic cross-sectional view of a comparative example solid-state imaging device. [Figure 5] Figure 5 shows the case in the solid-state imaging device of this disclosure where the width of the recess is relatively large. [Figure 6] Figure 6 shows the case in the solid-state imaging device of this disclosure where the width of the recess is relatively small. [Figure 7] Figure 7 is a schematic plan view showing another example of a textured pattern in the solid-state imaging device of this disclosure. [Figure 8] Figure 8 shows the reflectance of the solid-state imaging device of this disclosure and the solid-state imaging device of the comparative example as a function of the wavelength of incident light. [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 the recess area ratio corresponding to each color when the color filters are arranged in a Bayer pattern in the solid-state imaging device of the present disclosure.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described based on the drawings. The following description is illustrative and not limited thereto. Also, within the range where the effects are exhibited, it can be appropriately changed.

[0011] FIG. 1 is a schematic cross-sectional view of a solid-state imaging device 20 (image sensor) of the present embodiment, showing a range 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, it functions as a photoelectric conversion region that converts incident light into electric charges.

[0013] On the surface portion of the silicon substrate 1, an uneven pattern portion 2 including convex portions 8 and concave portions 10 is provided. A fixed charge film 3, which is a first material film, is formed on the surface of the uneven pattern portion 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 uneven pattern portion 2, the bottom surfaces of the concave portions 10, and the upper surfaces of the convex portions 8 with the same thickness. Also, the fixed charge film 3 does not completely fill the concave portions 10 and leaves voids. The 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. At this time, the surface of the silicon substrate 1 is damaged, and the state of the interface with the film formed thereon becomes unstable. On the other hand, by forming a film having fixed charges such as Al2O3 on the surface of the silicon substrate 1, the state of the interface can be stabilized.

[0015] Regarding the concavo-convex pattern portion 2, a plan view is shown in FIG. 2. In the present embodiment, each convex portion 8 is an independent square and is separated by the concave portion 10. The convex portion 8 has a width W and is arranged side by side vertically and horizontally. In both the vertical and horizontal directions, the arrangement period P (the sum of the width W and the interval between adjacent convex portions 8) is the same. In the example of FIG. 2, the period P is slightly more than twice the width W. Also, the rows of the convex portions 8 are arranged so that the positions of the convex portions 8 do not overlap with those of the adjacent rows.

[0016] Incidentally, it is most preferable that the side surface of the convex portion 8 is perpendicular to the surface of the silicon substrate 1 (the bottom surface of the concave portion 10). However, in order to exhibit the effects of the present embodiment, it is not essential to be perpendicular. That is, the side surface of the convex portion 8 may be inclined to have a tapered shape. For example, regarding the angle of the side surface of the convex portion 8, it is preferably at an angle of 30° or less, and more preferably at an angle of 15° or less, with respect to the surface perpendicular to the surface of the silicon substrate 1.

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

[0018] The light 21 incident on the solid-state imaging device 20 passes through the microlens section 6, color filter 5, oxide film 4, and uneven pattern section 2 before entering the silicon substrate 1, where it is photoelectrically converted. Since color mixing occurs when incident light leaks into adjacent pixels, a light-shielding film 7 is provided to suppress this. The light-shielding film 7 is formed using a highly light-shielding material, such as tungsten (W). The color filter 5 directs light of the desired wavelength band to each pixel in order to capture a color image. Therefore, the color filter 5 is not present in the case of a monochrome image sensor.

[0019] Figure 3 shows the area around the uneven pattern portion 2 in Figure 1. In the solid-state imaging device 20 of this embodiment, the uneven pattern portion 2 is provided on the surface of the 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 enclosed by the dashed line, allowing it to function as an anti-reflective layer 22.

[0020] In this regard, Figure 4 shows a comparative example solid-state imaging device 20a. In the solid-state imaging device 20a, the surface of the silicon substrate 1 is flat. A fixed charge film 3 is formed to cover the upper surface of the flat silicon substrate 1, and an anti-reflective film 9 is formed on top of it. On the anti-reflective film 9, an oxide film 4, a color filter 5, and a microlens section 6 are formed, similar to the solid-state imaging device 20 of this embodiment.

[0021] In the case of the comparative example solid-state imaging device 20a, the anti-reflective coating 9 is often made of Si3N4 (refractive index 1.94~2.05), Ta2O5 (refractive index 2.17), etc. Note that the refractive index is the value at a wavelength of 450 nm.

[0022] However, because the refractive index of silicon is high in the region from blue light to green light (especially in the blue light region), the refractive index of the anti-reflective film 9 becomes too low, making it difficult to suppress 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, while it is desirable to provide an anti-reflective film 9 with a refractive index of 2.74 or higher. However, no semiconductor film deposition material suitable for this purpose is known. In addition, in the case of the comparative solid-state imaging device 20a, a fixed charge film 3 with a low refractive index is formed beneath the anti-reflective film 9, further reducing the anti-reflective effect.

[0023] In contrast, the solid-state imaging device 20 of this embodiment provides an uneven pattern portion 2 on the surface of the silicon substrate 1, and embeds a fixed charge film 3 and an oxide film 4 having a lower refractive index than the silicon substrate 1 in the recesses 10, thereby realizing an anti-reflective layer 22 with a reduced effective refractive index.

[0024] Furthermore, the anti-reflective layer 22 is most effective in reducing reflectivity when its effective refractive index is equal to the geometric mean of the refractive indices of the upper and lower layers, i.e., the refractive index of the silicon substrate 1 and the refractive index of the oxide film 4. Therefore, the refractive index of the Si constituting the silicon substrate 1 is 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 anti-reflective layer 22 can be expressed by the following equation (1).

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

[0026] From equation (1), in order to bring the reflectance in the visible light region (wavelengths of approximately 400 nm to 650 nm) close to zero, it is preferable to set the effective refractive index of the anti-reflective layer 22 to approximately 2.37 to 2.8.

[0027] This is achieved by making the refractive index of the material embedded 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. Examples of specific materials include Al2O3 with a refractive index of 1.6 and SiO2 with a refractive index of 1.46.

[0028] Furthermore, the effective refractive index of the anti-reflective layer 22 is calculated by the average value obtained by weighting the refractive indices of the convex portion 8 and the recessed portion 10 according to the volume ratio of the convex portion 8 and the recessed portion 10. In other words, it is the product of the refractive index of the convex portion 8 and the volume ratio of the convex portion 8 plus the product of the refractive index of the recessed portion 10 and the volume ratio of the recessed portion 10. For example, if the volumes of the convex portion 8 and the recessed portion 10 account for 40% and 60% respectively, and the refractive index of the convex portion 8 is 4.67 and the refractive index of the recessed portion 10 is 1.47, then the effective refractive index of the anti-reflective 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 protrusion 8, the material (refractive index) used to fill the recess 10, and the target value of the effective refractive index.

[0030] Furthermore, with respect to the uneven pattern portion 2, it is desirable to design it not only for its characteristics as an anti-reflective layer 22, but also for its dark current properties.

[0031] When a textured pattern 2 is formed on the surface of the silicon substrate 1, the charge state on the silicon surface becomes unstable, which can increase the dark current. Dark current can cause image quality to deteriorate. In particular, it can cause images to appear blurry and white when shooting in dark conditions.

[0032] The dark current increases or decreases in proportion to the surface area of ​​the recess 10. Therefore, the increase in dark current can be suppressed by reducing the surface area of ​​the recess 10. To achieve this, it is preferable to reduce the refractive index of the material embedded in the recess 10. By embedding a material with a low refractive index in the recess 10, the volume ratio of the recess 10 required to realize the anti-reflective layer 22 with a desirable refractive index can be reduced. As a result, the surface area of ​​the recess 10 becomes smaller, and the increase in dark current can be suppressed.

[0033] Furthermore, embedding a material with a low refractive index in the concave portion 10 is also effective in reducing color mixing between pixels. One of the causes of color mixing is that scattering occurs when light passes through the uneven pattern portion 2. On the other hand, in order to suppress the scattering of transmitted light, it is effective to reduce the period P (see FIGS. 2 and 3) of the uneven pattern portion 2. More specifically, the effective period P E is made smaller than the wavelength of the transmitted light, thereby suppressing light diffraction and scattering. As a result, color mixing can be reduced.

[0034] The effective period P considering the refractive index E is calculated by obtaining the product of the dimensions and the refractive index for the convex portion 8 and the concave portion 10, respectively, and summing them. As an example, when the width of the convex portion 8 made of Si with a refractive index of 4.67 is 75 nm and the width of the concave portion 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 (more precisely, the period P) of the convex portion 8 and the concave portion 10 are the same, the lower the refractive index of the material embedded in the concave portion 10, the smaller the effective period P E becomes, and the scattering of incident light, and thus color mixing, is suppressed.

[0036] As described above, the desirable concave area ratio is determined from the target value of the effective refractive index of the antireflection layer 22. If the concave area ratio is the same, by reducing the width W of the convex portion 8, the period P becomes smaller, and the effective period P E also becomes smaller. However, since the minimum width of the convex portion 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 using an immersion ArF exposure machine, the minimum width that can be processed is considered to be about 75 nm. However, the technology of the present disclosure is not limited to this dimensional example.

[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 uneven pattern portion 2. By providing the fixed charge film 3, the charge on the surface of the silicon substrate 1 can be stabilized and dark current can be suppressed. Since the fixed charge film 3 also fills a part of the recess 10, it is desirable that it has a low refractive index. Therefore, it is desirable to use Al2O3 with a refractive index of 1.6 as the material for the fixed charge film 3. Al2O3 is one of the materials with a very low refractive index for a fixed charge film.

[0038] However, for the fixed charge film 3 to exhibit the above effects, it is preferable that it has a predetermined thickness, for example, a film thickness of 15 nm or more. On the other hand, as the material that fills the recess 10, it is preferable to have a high proportion of SiO2, which has an even lower refractive index than Al2O3. From this viewpoint, there is an upper limit to the preferred film thickness of the fixed charge film 3, for example, it is preferable to have a film thickness of 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 within 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 to fill this void.

[0040] Thus, when a fixed charge film 3 is formed on a silicon substrate 1, and then an oxide film 4 is formed on top of it, the refractive index decreases sequentially. Consequently, the refractive index difference at each interface becomes smaller, and the anti-reflective effect becomes more pronounced.

[0041] To form the uneven pattern portion 2, for example, a resist pattern is formed on the surface of the silicon substrate 1 using 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 the recesses 10, and the remaining portion becomes the convex portion 8.

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

[0043] In this embodiment, the area ratio of the recessed portion 10 to be etched is approximately 63%. In other words, in the plan view of Figure 2, the area occupied by the recessed portion 10 is approximately 63% of the total area of ​​the convex portion and the recessed portion 10.

[0044] In this embodiment, by using low refractive index Al2O3 and SiO2 as the materials to fill the recesses 10, the effective refractive index of the anti-reflective layer 22 can be set to a desired value while reducing the recess area ratio to 63%. In contrast, when other materials are used to fill the recesses 10, the recess area ratio required to achieve a desired effective refractive index of the anti-reflective layer 22 is as follows. Al2O3 only: 67% HfO + SiO2: 67% • ZrO + SiO2: 70%

[0045] In this way, by using a low refractive index material 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, we will further explain the optical effects.

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

[0048] In Figure 5, the width W of the protrusion 8 is set to 100 nm. If the area ratio of the recess is 63%, the period P is determined to be 227 nm. In this case, the incident light 21 that passes through the uneven pattern 2 begins to scatter due to diffraction. Scattering due to diffraction is more likely to occur as the width W and period P increase. Since light scattering causes color mixing in adjacent pixels, it is desirable to suppress it.

[0049] In contrast, Figure 6 shows the case where the dimensions are as described in Figures 1 to 3, that is, when the period P is 170 nm and the width W is 75 nm. In this case, even if the incident light 21 passes through the uneven pattern portion 2, scattering due to diffraction is unlikely to occur. In this way, by setting the period P and width W, scattering of the 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 recess is 63%, the width W will be 90 nm. From this point of view, it is preferable that the width W be 90 nm or less. However, even if the period P exceeds 200 nm, the effect of suppressing the reflection of incident light can be achieved by the anti-reflective layer 22.

[0051] Furthermore, in the above, the shape of the protrusion 8 in the plan view was assumed to be a square, as shown in Figure 2. In this case, the protrusion 8 is arranged to be most densely packed in both the horizontal and vertical directions in Figure 2.

[0052] In contrast, Figure 7 shows another example: when viewed from a direction perpendicular to the silicon substrate, that is, when the convex portion 8 in the plan view is a regular octagon. In this way, the spacing between the convex portions 8 can be reduced even in the diagonal direction, allowing for a denser arrangement.

[0053] In both Figure 2 and Figure 7, if the area ratio of the recesses 10 is set to the same 63%, the effect of reflectivity suppression by the uneven pattern 2 is equivalent. However, in Figure 7, the spacing between the protrusions 8 can be narrowed, resulting in a higher effect of suppressing light scattering.

[0054] Next, Figure 8 shows the results of measuring the reflectance with respect to the wavelength of incident light for the solid-state imaging device 20 of this embodiment and the solid-state imaging device 20a of the comparative example (Figure 4). However, this is the case for imaging devices for monochrome images that do not have a color filter 5. In addition, for the comparative example, Si3N4 with a refractive index of 1.95 was used for the anti-reflective coating 9.

[0055] As shown in Figure 8, the reflectance of the example is suppressed compared to the comparative example in most wavelength ranges. In particular, the reflectance is suppressed very significantly from the blue region at a wavelength of 400 nm to the yellow region at a wavelength of 570 nm.

[0056] Furthermore, although Figure 8 shows an imaging device for monochrome images as an example, in the case of an imaging device for color images equipped with a color filter 5, the area of ​​the recess can be changed and optimized for each color.

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

[0058] As shown in Figure 9, the desirable recess area ratio for lowering reflectance varies with wavelength. The area ratio of recess 10 that results in the lowest reflectance (i.e., the optimal area ratio), and the range of area ratios that result in lower reflectance (i.e., improved) than that of the comparative solid-state imaging device 20a are: • Blue: Optimal at 65%, improved between 60% and 70%. Green: Optimal at 63%, improved between 58% and 68%. • Red: Optimal at 62%, improved between 57% and 67%. Thus, the longer the wavelength of light, the lower the desirable area ratio becomes. Furthermore, for visible light, it can be said that reflectance improves when the area ratio is 57% or more and 70% or less. Furthermore, although not limited to blue, green, and red, if the system includes a first pixel for receiving light of a first wavelength and a second pixel for receiving light of a longer wavelength than the first wavelength, it is preferable that the ratio of the area occupied by recesses to the surface area of ​​the surface pattern in the first pixel is greater than the ratio of the area occupied by recesses to the surface 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 optimal recess area ratio in the photoelectric conversion region corresponding to each color. For example, in the example shown in Figure 10, when blue (B), green (G), and red (R) color filters are arranged in a Bayer array, the recess area ratio of the uneven pattern portion 2 provided on the silicon substrate 1 is set to the optimal value described above.

[0060] Although the above explanation used a back-illuminated solid-state imaging device as an example, similar effects can be obtained with a front-illuminated solid-state imaging device.

[0061] As described above, the solid-state imaging device of this disclosure can reduce the reflectivity on the surface of the silicon substrate 1 and suppress the increase in dark current. Furthermore, since the period P of the uneven pattern portion 2 provided on the silicon substrate 1 can be reduced, the generation of diffracted and scattered light can be suppressed, and color mixing with adjacent pixels can be suppressed. Therefore, the image quality of the captured image can be improved.

[0062] The embodiments described above may be modified in form and detail, provided that they do not deviate from the spirit of the claims. Furthermore, the contents of each embodiment can be combined and substituted as appropriate, as long as they do not impair the functions covered by this disclosure. [Industrial applicability]

[0063] The solid-state imaging device of this 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. Uneven pattern section 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 recesses 20 Solid-state imaging device 20a Solid-state imaging device (comparative example) 21 Incident light 22 Anti-reflection layer

Claims

1. In a solid-state imaging device having multiple pixels formed on a silicon substrate, Each of the aforementioned pixels is, A photoelectric conversion region formed on the surface of the silicon substrate, A surface of the silicon substrate in the photoelectric conversion region is provided with an uneven pattern including recesses and protrusions, A first material film covers the side surface of the uneven pattern, the bottom surface of the recess, and the top surface of the protrusion, while leaving voids within the recess, The system comprises a second material film that fills the aforementioned void, The refractive index of the first material film is greater than the refractive index of the second material film. A solid-state imaging device characterized in that the refractive indices of the first material film and the second material film are both 1.7 or less.

2. In claim 1, The solid-state imaging device is characterized in that the first material film covers the sides of the uneven pattern, the bottom surface of the recesses, and the top surface of the protrusions with the same thickness.

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

4. In claim 3, A solid-state imaging device characterized in that the thickness of the fixed charge film is 15 nm or more.

5. In claim 3, The aforementioned fixed charge film is Al ２ O ３ A solid-state imaging device characterized by comprising the following components.

6. In claim 1, A solid-state imaging device characterized in that the ratio of the area occupied by the recesses to the surface area of ​​the surface pattern is 57% or more and 70% or less.

7. In claim 1, A solid-state imaging device characterized in that the width of the protrusion is 90 nm or less.

8. In claim 1, A solid-state imaging device characterized in that the depth of the recesses in the aforementioned uneven pattern is 40 nm or more and 70 nm or less.

9. In claim 1, The aforementioned pixel includes a first pixel for receiving light of a first wavelength, It includes a second pixel for receiving light with a wavelength longer than the first wavelength, A solid-state imaging device characterized in that, in the first pixel, the ratio of the area occupied by the recess to the uneven pattern is greater than the ratio of the area occupied by the recess to the uneven pattern in the second pixel.

10. In claim 1, The aforementioned pixel includes a blue pixel for receiving blue light, a green pixel for receiving green light, and a red pixel for receiving red light. A solid-state imaging device characterized in that the ratio of the area occupied by the recess to the surface area of ​​the surface area is 60% or more and 70% or less for the blue pixels, 58% or more and 68% or less for the green pixels, and 57% or more and 67% or less for the red pixels.

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

12. In claim 1, The solid-state imaging device is characterized in that the side surface of the protrusion is at an angle of 30° or less with respect to a plane perpendicular to the surface of the silicon substrate.

Images