Solid-state imaging device

Abstract

To provide a solid imaging element with the lower height and the excellent sensitivity characteristic.SOLUTION: A solid imaging element 10 includes a semiconductor substrate 15 where a plurality of photoelectric conversion elements 16 are arranged two-dimensionally, color microlenses 12 each integrating a color filter and a microlens and formed on the semiconductor substrate 15 at a position where the color microlens can face each photoelectric conversion element 16, and a plurality of partition walls 13 disposed between the color microlenses 12. Thus, a plurality of pixels are arranged two-dimensionally. The partition wall 13 is formed of a transparent material.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] In recent years, the resolution of imaging devices installed in video cameras, digital cameras, and mobile phones with cameras has been increasing. As the pixels of solid-state imaging elements such as CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) sensors incorporated in imaging devices become finer, the amount of light incident on each pixel decreases, causing a problem of reduced sensitivity characteristics.

[0003] In order to prevent a decrease in sensitivity, a method is widely used for solid-state imaging devices in which microlenses are formed on the incident side of the light receiving element in one-to-one correspondence with pixels (photoelectric conversion elements). By forming microlenses, incident light can be efficiently focused on the photoelectric conversion element, improving sensitivity characteristics.

[0004] Each pixel of a solid-state imaging device is provided with a color filter that transmits light of a specific wavelength along the path of the incoming light, making it possible to obtain color information of the object. In general, a specific color color filter is formed for each pixel, and a large number of them are arranged in a regular pattern to obtain color-separated image information. The most common color filters are the three primary colors of red (R), green (G), and blue (B), or the complementary colors of cyan (C), magenta (M), and yellow (Y), with the three primary colors being particularly widely used.

[0005] Furthermore, as a technology used in solid-state imaging devices, a color microlens configuration in which a microlens and a color filter are integrated has been disclosed (see Patent Document 1). In the configuration disclosed in Patent Document 1, partitions are provided between the color microlenses, and the provision of the partitions is said to have the effect of suppressing color mixing caused by obliquely incident light. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2019 / 220861 Summary of the Invention [Problem to be solved by the invention]

[0007] The configuration described in Patent Document 1 uses a metal material for the partitions arranged between the color microlenses, and there is a risk that light incident on the pixels will be absorbed by the metal partitions, resulting in a decrease in sensitivity characteristics.

[0008] The present invention has been made in consideration of the above-mentioned problems, and provides a solid-state imaging device having a low profile and good sensitivity characteristics. [Means for solving the problem]

[0009] In order to solve the problem, one aspect of the present invention is a solid-state imaging element having a plurality of pixels arranged two-dimensionally, comprising: a semiconductor substrate on which a plurality of photoelectric conversion elements are arranged two-dimensionally; a color microlens, which is an integrated color filter and a microlens, formed on the semiconductor substrate at a position capable of facing each of the photoelectric conversion elements; and a plurality of partitions arranged between the plurality of color microlenses, wherein the partitions are formed of a transparent material. Effect of the Invention

[0010] According to the aspects of the present invention, it is possible to provide a solid-state imaging device having a low profile and good sensitivity characteristics. [Brief description of the drawings]

[0011] [Figure 1] 1 is a top view showing a partial outline of a solid-state imaging element according to an embodiment of the present invention. [Diagram 2]2 is a cross-sectional view showing a schematic structure of a solid-state imaging element taken along dotted line I-II in FIG. [Diagram 3] 1 is a cross-sectional view illustrating a schematic structure of a solid-state imaging element according to Comparative Example 1. FIG. [Figure 4] 11 is a cross-sectional view illustrating a schematic structure of a solid-state imaging element according to Comparative Example 2. FIG. [Diagram 5] FIG. 2A is a top view showing the structure of a solid-state imaging element used in a simulation in an embodiment of the present invention, and FIG. 2B is a cross-sectional view showing the structure of the solid-state imaging element used in the simulation. [Figure 6] FIG. 13 is a diagram showing sensitivity characteristics at normal incidence. [Figure 7] FIG. 13 is a diagram showing sensitivity characteristics at oblique incidence. [Figure 8] FIG. 13 is a diagram showing the relationship between the ratio of the height of the partition wall to the height of the color microlenses (height ratio R) and SNR10 in an embodiment of the present invention. [Figure 9] FIG. 11 is a diagram showing the relationship between the width of the partition wall and SNR10 in the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a solid-state imaging device according to an embodiment of the present invention will be described with reference to the drawings. Here, the configurations shown in the figures are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc. differ from the actual ones. Furthermore, the embodiments shown below are examples of configurations for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the materials, shapes, structures, etc. of the components described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims described in the claims.

[0013] 1, in the solid-state imaging element of this embodiment, an array of four pixels is periodically arranged in one unit according to a Bayer array in which the ratio of the number of green pixels 11G to the number of red pixels 11R to the number of blue pixels 11B is 2:1:1. The red pixels 11R are pixels that detect the intensity of red wavelength light, the green pixels 11G are pixels that detect the intensity of green wavelength light, and the blue pixels 11B are pixels that detect the intensity of blue wavelength light. In a plan view, each color microlens 12 corresponds to the area of ​​a corresponding pixel.

[0014] FIG. 2 is a cross-sectional view showing a schematic structure of the solid-state imaging device 10 taken along dotted line I-II in FIG. 2, in the solid-state imaging device 10, a plurality of photoelectric conversion elements 16 that convert incident light into electric charges are provided inside a semiconductor substrate 15. The photoelectric conversion element 16 is provided for each pixel 11 shown in FIG. 1, and the plurality of photoelectric conversion elements 16 are arranged two-dimensionally. The semiconductor substrate 15 is made of, for example, silicon. The photoelectric conversion element 16 is formed by adding an element such as phosphorus to the semiconductor substrate 15.

[0015] A planarization layer 14 is formed on the semiconductor substrate 15. The planarization layer 14 is formed of, for example, a silicon oxide film. In order to reduce reflection of incident light, an anti-reflection film made of a metal oxide may be formed at the interface between the planarization layer 14 and the semiconductor substrate 15. A plurality of color microlenses 12, in which a color filter and a microlens are integrated, are formed on the planarization layer 14. A color microlens 12R is formed corresponding to the red pixel 11R, a color microlens 12G is formed corresponding to the green pixel 11G, and a color microlens 12B is formed corresponding to the blue pixel 11B.

[0016] The color microlens 12 is made of a photosensitive organic material containing a pigment or dye that selectively transmits wavelengths corresponding to green, blue, and red, for example. The color microlens 12 has a refractive index in the range of 1.5 to 2.0, and an extinction coefficient in the range of 0 to 0.4. The color microlens 12 also has a light transmittance in the range of 80% to 100% over the entire visible light range, for example. The color microlenses 12 are formed by transferring the shape of the lens matrix to the color microlenses 12 by dry etching using the lens matrix as a mask. In order to reduce the reflection of incident light, an anti-reflection film made of, for example, a silicon oxide film may be formed on the upper portion (upper surface) of the color microlenses 12.

[0017] That is, in this embodiment, the above-mentioned "color microlens 12" means a microlens formed of a colored resin. More specifically, the color microlens 12 is a microlens formed of a colored resin, and is a microlens including a color filter flat portion 12a formed on the planarization layer 14 and a color filter lens portion 12b formed on the color filter flat portion 12a, as shown in Fig. 2. The surface of the color filter lens portion 12b opposite to the color filter flat portion 12a has a lens shape (for example, a substantially hemispherical lens shape).

[0018] 2, the flat portion height A, which is the thickness (film thickness) of the color filter flat portion 12a, is defined as, for example, the height from the surface in contact with the flattening layer 14 to the surface in contact with the bottom of the color filter lens portion 12b. The lens portion height B, which is the thickness (film thickness) of the color filter lens portion 12b, is defined as, for example, the height in the thickness direction from the bottom surface in contact with the color filter flat portion 12a to the top of the lens shape of the color filter lens portion 12b. Note that the above-mentioned "bottom of the color filter lens portion 12b" refers to the point located closest to the partition wall 13 among the regions in which lenses are formed in each color microlens 12.

[0019] In this embodiment, the ratio of the lens portion height B to the sum of the flat portion height A and the lens portion height B (B / (A+B)) is preferably within the range of 0.5 or more and less than 1, more preferably within the range of 0.6 or more and 0.9 or less, and even more preferably within the range of 0.7 or more and 0.8 or less. If the ratio is lower than 0.5, the light receiving sensitivity may decrease because the color filter lens portion 12b does not sufficiently collect light, which may result in a deterioration in the S / N ratio of the pixel, and thus in a deterioration in image quality characteristics.

[0020] Moreover, the sum of the flat portion height A and the lens portion height B is preferably in the range of 500 nm to 800 nm, more preferably in the range of 700 nm to 800 nm. If the sum of the flat portion height A and the lens portion height B is within the above numerical range, the function as a color filter is fully exhibited. Specifically, if the sum of the flat portion height A and the lens portion height B is lower than 500 nm, the transmittance of incident light having a wavelength outside the selected wavelength range of each color filter increases, which may deteriorate the wavelength selectivity of each color filter and deteriorate the S / N ratio of the pixel. Furthermore, since each color filter has a property of slightly absorbing light having a wavelength in the selected wavelength range, if the sum of the flat portion height A and the lens portion height B is higher than 800 nm, this may cause a decrease in the transmittance of each color filter for incident light having a wavelength in the selected wavelength range of each color filter, and the amount of light reaching the photoelectric conversion element of each pixel may decrease. As a result, the light receiving sensitivity of the pixel may decrease, and the S / N ratio of the pixel may deteriorate.

[0021] Moreover, the width WL of the color microlens 12 in the horizontal direction of each pixel is preferably in the range of 0.6 μm to 2.0 μm, more preferably in the range of 0.6 μm to 1.0 μm, and even more preferably in the range of 0.6 μm to 0.8 μm. This is because it is difficult to make the width WL of the color microlens 12 in the horizontal direction of each pixel narrower than 0.6 μm with the current process capability (manufacturing technology). Also, if the width WL of the color microlens 12 in the horizontal direction of each pixel is wider than 2.0 μm, there is a risk that the contribution of the low height to the improvement of sensitivity characteristics will be reduced.

[0022] 2, the solid-state imaging element 10 according to the present embodiment is most preferably in a form in which the color microlenses 12 do not cover the surfaces of the partitions 13, but the present invention is not limited to this. For example, a part of the surface of the partitions 13 may be covered by the color microlenses 12. Specifically, the surface of the partitions 13 may be covered by the color microlenses 12 so long as the area of ​​the surface of the partitions 13 is less than 50%. Within the above numerical range, it is possible to guide even light incident on the ends of the color microlenses 12 to the photoelectric conversion elements 16.

[0023] A plurality of partitions 13 are formed on a semiconductor substrate 15 and disposed between any two adjacent color microlenses 12. For example, the partitions 13 are disposed between a green color microlens 12G and a red color microlens 12R. The partitions 13 define pixels corresponding to the respective photoelectric conversion elements 16. In the embodiment, the bottoms of the partitions 13 are formed to contact the upper surface of the planarization layer 14. The partition 13 in this embodiment is intended to suppress color mixing between adjacent pixels due to obliquely incident light.

[0024] The partition 13 may be made of any transparent material, and may be made of a transparent inorganic compound material. The partition 13 may be made of, for example, silicon oxide (SiO2), silicon nitride (SiN), silicon oxynitride (SiON), etc. The material constituting the partition 13 is not limited to the above-mentioned materials, and the partition 13 may be made of other suitable materials having a transparent inorganic compound, etc. The partition 13 has, for example, a refractive index in the range of 1.4 to 1.9, and an extinction coefficient in the range of 0 to 0.01. The partition 13 also has, for example, a light transmittance in the range of 80% to 100% over the entire visible light range. If the partition 13 is made of silicon nitride (SiN), the refractive index is 1.9.

[0025] In this embodiment, the refractive index of the partition wall 13 may be the same on the front side of the partition wall 13 and on the back side (flattening layer 14 side) of the partition wall 13, or may gradually decrease from the back side of the partition wall 13 toward the front side of the partition wall 13. By gradually decreasing the refractive index of the partition wall 13 from the back side of the partition wall 13 toward the front side of the partition wall 13, it is possible to further improve the sensitivity characteristics with respect to incident light having a relatively shallow oblique incident angle (for example, an incident angle of about 15° to 30°). Alternatively, the refractive index of the partition 13 may increase from the back surface side of the partition 13 toward the front surface side of the partition 13. By gradually increasing the refractive index of the partition 13 from the back surface side of the partition 13 toward the front surface side of the partition 13, it is possible to further improve the sensitivity characteristics with respect to incident light having a relatively deep oblique incident angle (for example, an incident angle of about 35° to 45°).

[0026] As described above, when the refractive index of the partition walls 13 is to be gradient, the partition walls 13 may be formed by the following method. Silicon oxide (SiO2), silicon nitride (SiN), silicon oxynitride (SiON), etc., which can be used as the material of the partition 13, can generally be formed by using a sputtering method. This sputtering method allows the formation conditions, specifically the oxygen concentration, to be continuously adjusted. Thus, by continuously adjusting (increasing or decreasing) the oxygen concentration when forming the above material of the partition 13, the refractive index of the partition 13 can be continuously changed.

[0027] The partition wall 13 has a rectangular cross-sectional shape in the thickness direction, for example, as shown in Fig. 2. The width WW of the partition wall 13 is smaller than the height HW of the partition wall 13, for example. In this embodiment, the height HW of the partition 13 is a ratio of the height HW of the partition 13 to the height HL of the color microlenses 12 (i.e., the sum of the flat portion height A and the lens portion height B), and is preferably in the range of 0.6 to 1.1, and more preferably in the range of 0.8 to 1.0. If the ratio is less than 0.6, the partition 13 is too low to function as a partition, and the obliquely incident light component may move to an adjacent pixel, causing color mixing and degrading the sensitivity characteristics. If the ratio is more than 1.1, the partition 13 is too high, which is problematic from the viewpoint of reducing the height of the solid-state imaging element 10.

[0028] The height HW of the partition 13 is a ratio of the height HW of the partition 13 to the flat portion height A of the flat portion 12a of the color filter, and is preferably in the range of 0.8 to 1.1, more preferably in the range of 0.9 to 1.0. If the ratio is less than 0.8, the partition 13 is too low to function as a partition, and the obliquely incident light component may move to an adjacent pixel, causing color mixing and degrading the sensitivity characteristics. If the ratio is more than 1.1, the partition 13 is too high, which is problematic from the viewpoint of reducing the height of the solid-state imaging element 10.

[0029] In this embodiment, the width WW of the partition 13 is preferably in the range of 0.05 μm to 0.15 μm, and more preferably in the range of 0.2 μm to 0.10 μm. The reason is that if the width WW of the partition 13 is smaller than 0.05 μm, it is difficult to form the partition with the current process capability (production technology). In other words, if the WW width of the partition 13 is smaller than 0.05 μm, it is difficult to form the partition 13. In addition, if the width WW of the partition 13 is larger than 0.15 μm, the area occupied by the partition 13 in the pixel increases, so that light is directly incident on the partition 13, and the amount of light incident on the color microlens 12 decreases, which may result in a deterioration in sensitivity characteristics.

[0030] The width WW of the partition 13 is a ratio of the width WW of the partition 13 to the width WL of the color microlens 12, and is preferably in the range of 0.1 to 0.3, more preferably in the range of 0.1 to 0.2. If the ratio is less than 0.1, the partition 13 is too thin to function as a partition, and the obliquely incident light component may move to an adjacent pixel, causing color mixing and degrading the sensitivity characteristics. If the ratio is more than 0.3, the partition 13 is too thick to occupy an area of ​​the pixel that is occupied by the partition 13, so that light is directly incident on the partition 13, and the amount of light incident on the color microlens 12 is reduced, which may degrade the sensitivity characteristics.

[0031] In this embodiment, the partition 13 has a rectangular cross-sectional shape in the thickness direction, but the present invention is not limited to this. The partition 13 may have a trapezoidal cross-sectional shape in the thickness direction, for example. When the partition 13 has a trapezoidal cross-sectional shape in the thickness direction, the width of the rear surface of the partition 13 (the surface in contact with the planarizing layer 14) may be wider or narrower than the width of the front surface of the partition 13. By making the partition 13 have a trapezoidal cross-sectional shape in the thickness direction, it is possible to improve the sensitivity characteristics to a specific obliquely incident light component. The cross-sectional shape of the partition 13 in the thickness direction may be such that the width of the central part of the partition 13 is wider or narrower than the widths of the rear surface and the front surface of the partition 13. By making the cross-sectional shape of the partition 13 into the above-mentioned shape, it is possible to improve the sensitivity characteristic to a specific obliquely incident light component.

[0032] Next, the reason why the structure of the solid-state imaging element according to the embodiment of the present invention enables the solid-state imaging element to have a low height and improve sensitivity characteristics will be described.

[0033] Comparative Example 1 shown in Fig. 3 is a solid-state imaging element having a structure in which the color filter 17 and the microlens 18 are independent. That is, in the solid-state imaging element of Comparative Example 1 shown in Fig. 3, an interface exists between the color filter 17 and the microlens 18. The sum of the heights of the color filter 17 and the microlens 18 is nearly 1.7 times higher than the height of the color microlens 12 of this embodiment. If the distance from the top (apex) of the microlens 18 to the photoelectric conversion element 16 (not shown) is long, part of the light incident on the pixel moves to an adjacent pixel, resulting in a decrease in sensitivity characteristics. 3, a green color filter 17G and a red color filter 17R are illustrated as the color filters 17, and the blue color filter 17B is omitted. Also, in FIG. 3, the photoelectric conversion element 16 is also omitted.

[0034] In contrast, in this embodiment, a color microlens structure is adopted in which a color filter having a spectral function and a microlens having a light-collecting function are integrated, thereby making it possible to reduce the height of the solid-state imaging element compared to the solid-state imaging element of Comparative Example 1. Furthermore, by reducing the height of the solid-state imaging element, it is possible to suppress color mixing of obliquely incident light with adjacent pixels, and it becomes possible to efficiently guide light incident on a pixel to the photoelectric conversion element 16, thereby improving the sensitivity characteristics.

[0035] In the solid-state imaging element of Comparative Example 1, the partition 19 has a lower portion formed using a metal material. Therefore, a part of the light incident on the pixel is absorbed by the metal partition 19, and the incident light cannot be efficiently guided to the photoelectric conversion element 16, resulting in a decrease in sensitivity characteristics. In contrast, in this embodiment, a transparent inorganic compound is used for the partition 13, and the partition 13 itself has extremely low light absorption, making it possible to efficiently guide incident light to the photoelectric conversion element 16, thereby improving the sensitivity characteristics.

[0036] 4 is a solid-state imaging element having a low-profile color microlens structure, but does not have partitions 13 between the color microlenses 12. If partitions 13 are not provided between the color microlenses 12, part of the obliquely incident light component entering a pixel moves to an adjacent pixel, causing color mixing. In FIG. 4, the photoelectric conversion element 16 is omitted.

[0037] In contrast, in this embodiment, by arranging partitions 13 between the color microlenses 12, color mixing with adjacent pixels, which occurs when a portion of the obliquely incident light component incident on a pixel moves to an adjacent pixel, can be suppressed, thereby improving the sensitivity characteristics. That is, in the present embodiment, the partition 13 is formed using a transparent inorganic compound, and therefore, it is possible to reflect a part of the incident light without absorbing it, and therefore, the incident light can be efficiently guided to the photoelectric conversion element 16, and it is considered that the sensitivity characteristics are improved. In addition, in this embodiment, the partitions 13 are formed using a transparent inorganic compound, and the color microlenses 12 are used to reduce the height of the microlenses themselves. Therefore, even if a portion of the obliquely incident light component incident on a pixel passes through the partitions 13, it is possible to reduce the amount of color mixing with adjacent pixels, and it is believed that the sensitivity characteristics are improved.

[0038] [Example] Next, an embodiment of the solid-state imaging device of the present invention will be described using simulation results. The simulation was performed using the finite difference time domain method (FDTD method), which is a type of electromagnetic field analysis method. The simulation conditions are as follows.

[0039] FIG. 5 shows the structure of the solid-state imaging device 10 used in the simulation. In FIG. 5(a), which is a top view of the solid-state imaging device 10, the widths of the red pixel 11R, the green pixel 11G, and the blue pixel 11B are 0.9 μm in both the X-axis direction and the Y-axis direction. In FIG. 5(b), which is a cross-sectional view of the solid-state imaging device 10 taken along the dotted line I-II in FIG. 5(a), the red color microlens 12R transmits red wavelength light and has a length in the X-axis direction and a length in the Y-axis direction of 0.9 μm. The green color microlens 12G transmits green wavelength light and has a length in the X-axis direction and a length in the Y-axis direction of 0.9 μm. The blue color microlens 12B (not shown) transmits blue wavelength light and has a length in the X-axis direction and a length in the Y-axis direction of 0.9 μm. The flattening layer 14 has a height in the Z-axis direction of 0.1 μm, a refractive index of 1.6, and an extinction coefficient of 0. The semiconductor substrate 15 has a length in the X-axis direction and a length in the Y-axis direction of 1.8 μm, and a height in the Z-axis direction of 3 μm. The incident light was parallel, and the vibration direction of the electric field was the X-axis direction.

[0040] The refractive index and extinction coefficient of the color microlens 12R were measured by applying a photosensitive material containing CI Pigment Red 117, CI Pigment Red 48:1, and CI Pigment Yellow as coloring materials, organic solvents such as cyclohexanone or PGMEA, polymer varnish, monomers, and initiators to a thickness of 0.6 μm on a silicon substrate, exposing the substrate to light and heating, and then measuring the refractive index and extinction coefficient using a spectroscopic ellipsometer. Specifically, the color microlens 12R (red resist) had a refractive index of 1.87 at a wavelength of 600 nm and an extinction coefficient of 0.01 (0.008) at a wavelength of 600 nm.

[0041] The refractive index and extinction coefficient of the color microlens 12G were measured by applying a photosensitive material containing CI Pigment Yellow 139, CI Pigment Green 36, and CI Pigment Blue 15:6 as coloring materials, organic solvents such as cyclohexanone or PGMEA, polymer varnish, monomers, and initiators to a thickness of 0.6 μm on a silicon substrate, exposing the substrate to light and heating it, and then measuring the refractive index and extinction coefficient using a spectroscopic ellipsometer. Specifically, the color microlens 12G (green resist) had a refractive index of 1.74 at a wavelength of 520 nm and an extinction coefficient of 0.01 at a wavelength of 520 nm.

[0042] The refractive index and extinction coefficient of the color microlens 12B were measured by applying a photosensitive material containing CI Pigment Blue 15:6 and CI Pigment Violet 23 as coloring materials, organic solvents such as cyclohexanone or PGMEA, polymer varnish, monomers, and initiators to a thickness of 0.6 μm on a silicon substrate, exposing the substrate to light and heating it, and then measuring the refractive index and extinction coefficient using a spectroscopic ellipsometer. Specifically, the color microlens 12B (blue resist) had a refractive index of 1.65 at a wavelength of 450 nm and an extinction coefficient of 0.01 at a wavelength of 450 nm. The heights of the color microlenses 12R, 12G, and 12B of each color are all set to the same height.

[0043] The partition 13 has a refractive index and an extinction coefficient of silicon oxide, which is a transparent inorganic compound. Specifically, the partition 13 has a refractive index of 1.46 and an extinction coefficient of 0. The simulation was performed with the height of the partition 13 in the range of 0 μm to 1 μm, and the width of the partition 13 in the range of 0 μm to 0.3 μm. The incident light was parallel, and the vibration direction of the electric field was the X-axis direction. The wavelength of the incident light was a single wavelength, and 31 conditions were tested at 10 nm intervals from 400 nm to 700 nm per level.

[0044] A simulation was performed under the above conditions, and the light intensity absorbed in each pixel from the surface of the semiconductor substrate 15 to a depth of 3 μm was calculated. The sensitivity (light receiving sensitivity) was calculated as the ratio of the intensity of the light power absorbed in each pixel from the surface of the semiconductor substrate 15 to a depth of 3 μm, relative to the intensity of the light power incident on one pixel. It is preferable that the sensitivity (light receiving sensitivity) calculated in this way be a high value. SNR10 was used as a performance index of image quality. This is used as an index of image quality after color correction processing etc. in solid-state image sensors for mobile phone cameras.

[0045] In this embodiment, when the F value is set to 1.8, the sensitivity of each pixel is regarded as quantum efficiency, and the SNR10 is calculated from the spectral sensitivity characteristics calculated from the simulation results for each level. The SNR10 value has units of illuminance (lux), and it is preferable that it is a low numerical value. In addition, the color difference (ΔE) is also calculated at the same time as the SNR10, and it is preferable that both of these are low numerical values. Here, the above-mentioned "color difference (ΔE)" refers to the color value (L * a * b * This refers to the difference between the color value in the color space of the color system and the calculated color value.

[0046] 6 shows sensitivity characteristics at normal incidence (incident angle 0°) of Example, Comparative Example 1, and Comparative Example 2. Here, the above-mentioned “normal incidence (incident angle 0°)” refers to a direction perpendicular to the surface of semiconductor substrate 15. 7 shows the sensitivity characteristics at oblique incidence (incident angle 20°) of Example, Comparative Example 1, and Comparative Example 2. Here, the above-mentioned "oblique incidence (incident angle 20°)" refers to a direction inclined by 20° from the perpendicular direction to the surface of semiconductor substrate 15. 6 and 7, it can be seen that the sensitivity characteristics for each of the colors red (R), green (G), and blue (B) are improved in the Example compared to Comparative Examples 1 and 2. It can be seen that the sensitivity characteristics are significantly improved in the Example compared to Comparative Example 1, especially in the case of oblique incidence (see FIG. 7).

[0047] From the above results, it has been confirmed that by combining and arranging a color microlens structure (color microlenses 12) with a transparent material, in particular, a partition 13 formed of an inorganic compound, it is possible to provide a solid-state imaging element 10 that is low in height and has good sensitivity characteristics. FIG. 8 shows the relationship between the ratio R of the height of the partition 13 to the height of the color microlens 12 (height of the partition 13 / height of the color microlens 12) and the SNR10 and color difference (ΔE), which are performance indexes of the solid-state imaging element 10. FIG. 9 shows the relationship between the width of the barrier rib 13 and the SNR10 and color difference (ΔE).

[0048] From the results in Figure 8, it can be seen that in the region where the SNR10 value is low and the color difference is also small (i.e., the region where the ΔE value is small) for the height of the partition 13, the ratio R of the height of the partition 13 to the height of the color microlens 12 is in the range of 0.6 or more and 1.1 or less, and the sensitivity characteristics are good in this region. From the results in FIG. 9, it can be seen that the width of the partition 13 in the range of 0.05 μm to 0.15 μm provides a small SNR10 value and a small color difference (ΔE) value, and in this range the sensitivity characteristics are excellent. [Explanation of symbols]

[0049] 10 Solid-state imaging element 11 pixels 11B Blue pixel 11G Green pixel 11R Red pixel 12 Color Micro Lenses 12B Blue color micro lens 12G Green color micro lens 12R Red color micro lens 12a Color filter flat part 12b Color filter lens section 13 Bulkhead 14 Planarization layer 15 Semiconductor Substrates 16 Photoelectric conversion element 17 Color Filter 17B Blue color filter 17G Green color filter 17R Red color filter 18 Microlenses 19 Partitions (partitions including metal parts, metal partitions) A Flat part height B Lens height WL Color Micro Lens Width WW bulkhead width HL Color microlens height HW Height of bulkhead

Claims

1. A semiconductor substrate on which a plurality of photoelectric conversion elements are two-dimensionally arranged; a plurality of color microlenses, each of which is an integral part of a color filter and a microlens, formed on the semiconductor substrate at a position capable of facing each of the photoelectric conversion elements; a partition wall disposed between each of the color microlenses, thereby forming a solid-state imaging element in which a plurality of pixels are arranged two-dimensionally, The partition is made of a transparent material, The color microlenses are separated by the partitions so as not to contact each other, a ratio of a width of the partition wall to a width of each of the color microlenses is within a range of 0.1 to 0.

3.

2. The width of one end of the partition wall in the thickness direction is wider or narrower than the width of the other end, or 2. The solid-state imaging device according to claim 1, wherein the width of the central portion of the partition is wider or narrower than the widths of one end and the other end of the partition in the thickness direction.

3. 3. The solid-state imaging device according to claim 1, wherein a ratio of the height of said partition wall to the height of each of said color microlenses (partition wall height / color microlens height) is within a range of 0.6 to 1.

1.

4. 4. The solid-state imaging device according to claim 1, wherein the width of the partition is within a range of 0.05 [mu]m to 0.15 [mu]m.

Images