JP2017118065A - Solid-state imaging element and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-state imaging element capable of reducing a difference in quantum efficiency among respective colors while improving the quantum efficiency.SOLUTION: In a solid-state imaging element, on a semiconductor substrate 21 on which a plurality of photodiodes 22 are arranged, a transparent flattened layer 23, and color microlenses 61, 62, and 63 of a plurality of colors formed so as to correspond to the plurality of photodiodes 22, respectively, are laminated in this order. A height of each of the color microlenses 61, 62, and 63 of the plurality of colors is different for each color.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solid-state imaging device and a manufacturing method thereof.

  Video cameras and digital cameras are increasing in pixel count. Therefore, a solid-state image sensor incorporated in a video camera or a digital camera also has high pixels, and the pixel size is expected to be reduced to 1 μm or less. As the pixel size is further miniaturized, the amount of light incident on the pixel is reduced as the pixel area is reduced, and the sensitivity of the photodiode is lowered. In addition, when the line width of the wiring is reduced and the dielectric layer is thinned, the pixel is easily affected by noise. In order to solve these problems, a microlens is placed above the color filter formed corresponding to the photodiode formed on the semiconductor substrate that will be a solid-state image sensor, and the light sensitivity is collected by collecting the incident light. Is increasing.

  However, even if a microlens is disposed, incident light cannot be efficiently collected if the distance between the microlens and a photodiode made of CMOS or CCD as a light receiving element is large. For example, if the pixel size is 1.5 μm and the distance from the microlens to the photodiode is 5 μm, even if the light incident from the camera lens has an angle of 20 °, the angle from the microlens to the photodiode is 10 °. Only light within a range of a certain angle can be taken in, and the light collection efficiency is deteriorated, leading to a decrease in sensitivity of the solid-state imaging device. Therefore, a thin color filter layer is required.

  A conventional solid-state imaging device having an on-chip color filter (a color filter that is formed on a semiconductor substrate on which a photodiode is formed and makes light of a predetermined wavelength incident on the corresponding photodiode) has a plurality of photodiodes on the semiconductor substrate. A silicon oxide film or a silicon nitrogen oxide film is formed on the surface of the semiconductor substrate. A transparent planarization layer (PL) made of a transparent resin is formed on the semiconductor substrate. On the transparent planarization layer (PL), a green color filter, a blue color filter, and a red color filter made of a resin in which a pigment such as a pigment or a dye is dispersed are formed corresponding to the photodiode. A smoothing layer (FL) made of a transparent resin is formed on these color filters, and a plurality of microlenses are formed thereon corresponding to the photodiodes.

  As a microlens, for example, Patent Document 1 discloses a color microlens that is formed with a pigment-dispersed color resist or a dye-based color resist without using a transparent resin layer. According to the technique described in Patent Document 1, it is possible to reduce the transparent resin material and the coating process normally used for the microlens. In addition, since the distance between the lens and the photodiode can be shortened, the quantum efficiency can be improved.

JP 2003-332547 A

However, the color microlens is different from the microlens made of transparent resin in that the condensing performance is different for each color. Therefore, there is a possibility that a large difference in quantum efficiency is caused between colors.
An object of the present invention is to provide a solid-state imaging device capable of reducing the difference in quantum efficiency of each color and a method of manufacturing the same while improving the quantum efficiency.

  In one embodiment of the present invention, a transparent planarization layer and a plurality of color microlenses formed in correspondence with each of the plurality of photodiodes are stacked in this order on a semiconductor substrate on which the plurality of photodiodes are arranged. The solid-state imaging device is characterized in that the heights of the color microlenses of different colors are different for each color.

  According to the present invention, since the color microlens is used, the distance between the lens and the photodiode can be shortened, and the quantum efficiency can be improved. Further, by adjusting the height of the color microlens for each color, it is possible to reduce the difference in the condensing characteristics of each color and to reduce the difference in quantum efficiency of each color. Thereby, the difference in the quantum efficiency of each color can be reduced while improving the quantum efficiency.

It is an end view showing the structure of a solid-state image sensor. It is a top view showing a color filter arrangement | sequence. It is an end view for demonstrating the formation order of the color microlens in a photolithographic system. It is a top view showing the transmittance | permeability distribution per 1 pixel of a photomask. It is a graph showing the quantum efficiency of each color with respect to each wavelength of a color microlens with the same height. It is a graph showing the quantum efficiency of each color with respect to each wavelength of the color microlens from which the height formed with the photolithographic system differs. It is an end view for demonstrating the formation order of the color microlens in an etching process. It is a graph showing the quantum efficiency of each color with respect to each wavelength of the color microlens formed in the dry etching method and having a different height. It is an end view for demonstrating the formation order of the color microlens which has a partition.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
(Constitution)
FIG. 1 is an end view showing the structure of a solid-state imaging device.
As shown in FIGS. 1A and 1B, the solid-state imaging device has a transparent planarization layer 23 for planarizing irregularities on the surface of the semiconductor substrate 21 on the semiconductor substrate 21 on which a plurality of photodiodes 22 are formed. , And a plurality of color microlenses 61, 62, 63 formed in correspondence with the photodiodes 22 are stacked in this order. As the color microlenses 61, 62, and 63 of a plurality of colors, for example, a green color microlens 61 that transmits green light, a blue color microlens 62 that transmits blue light, and a red color microlens that transmits red light. There are 63. Each of the color microlenses 61, 62, and 63 has a hemispherical or parabolic convex shape at the end far from the photodiode 22.

In addition, each of the color microlenses 61, 62, 63 of different colors has a different height for each color (green, blue, red). Specifically, the height of the red color microlens 63> the height of the green color microlens 61> the height of the blue color microlens 62.
FIG. 2 is a plan view showing the color filter array 20. In the arrangement shown in FIG. 2, a G (green) filter (green color microlens 61) is provided every other pixel, and an R (red) filter (red color microlens 63) is arranged every other row between adjacent G filters. This is a so-called Bayer arrangement in which a B (blue) filter (blue color microlens 62) is provided.

  The color microlenses 61, 62, and 63 include a microlens main body portion 64 disposed on the transparent planarizing layer 23 and a rectangular parallelepiped convex lens portion 65 formed on the microlens main body portion 64. The convex lens portion 65 is formed in a convex lens shape having a convex surface in the normal direction of the photodiode 22. As a result, the end on the side far from the photodiode 22 forms a hemispherical or parabolic convex shape, that is, a rectangular parallelepiped shape having a convex lens shape. The height of the color microlenses 61, 62, and 63 is set to 0.2 μm or more and 0.8 μm or less. Further, the height of the convex lens portion 65 is set to 0.1 μm or more and 0.7 μm or less.

(Production method)
Next, the manufacturing method of a solid-state image sensor is demonstrated. In the first embodiment, the color microlenses 61, 62, and 63 are formed by a photolithography method.
First, as shown in FIG. 3A, a plurality of photodiodes 22 are formed on the semiconductor substrate 21. Next, a silicon oxide film or a silicon nitrogen oxide film is formed on the semiconductor substrate 21.
Next, a transparent planarization layer (PL) 23 made of a transparent resin is formed on the semiconductor substrate 21. The transparent planarization layer (PL) 23 planarizes the irregularities on the surface of the semiconductor substrate 21 and functions as an adhesive layer between the color microlenses 61, 62, 63 and the semiconductor substrate 21.

  Next, a green color resist 24 containing a photosensitive component is applied on the transparent planarizing layer 23. As the color material of the green color resist 24, for example, pigment green (PG) 36 or PG58 and pigment yellow (PY) 150 are used, and the pigment concentration of the green color resist 24 is adjusted to be, for example, 50% or more. It is preferable. The film thickness of the green color resist 24 is set to 500 nm, for example, by setting the coating rotation speed of the coating apparatus to 1200 rpm. Further, by heating the green color resist 24 at a temperature of 150 degrees or less (for example, 70 degrees), the green color resist 24 is imparted with a certain degree of solvent resistance, although not completely cured.

  Next, as shown in FIG. 3B, a green color photomask 40 having a transmittance distribution 10 that can be formed into a hemispherical or parabolic convex shape is used to form a green color resist 24. Perform pattern exposure and development. Next, thermosetting is performed at a temperature of 300 degrees or less (for example, 200 degrees), which is a temperature that does not affect the photoelectric conversion characteristics of the photodiode 22, and the green color microlens 61 is formed. At this time, the green color resist 24 is removed from the place for forming the blue color microlens 62 and the red color microlens 63.

FIG. 4 is a plan view showing the transmittance distribution 10 per pixel of the photomask 40.
The photomask 40 has a size four times as large as a pattern to be actually formed, and is subjected to pattern exposure after being reduced to ¼. In addition, the photomask 40 has concentric gradations (gray scales) in which gradation levels are set for each of a circular region and an annular region divided by concentric circles. The concentric gradation is formed, for example, by adjusting the number of fine black dots (or white dots) per unit area on the photomask 40 that have a size equal to or smaller than the wavelength of the exposure light when reduced by ¼. The number of black dots is increased as the area (circular area or annular area) closer to the center. Thereby, the transmittance | permeability reduces in the area | region (circular area | region, annular area) near a center part. For example, the central region (circular region 11) has a transmittance of 20 to 25%, the second region (annular region 12) from the center has a transmittance of 25 to 30%, and the third annular region 13 has a transmittance. 30 to 35%, the fourth annular region 14 has a transmittance of 35 to 40%, and the fifth annular region 15 has a transmittance of 40 to 45%.

The same applies to the photomask 41 for the blue region and the photomask 42 for the red region.
Next, as shown in FIG. 3C, a blue color resist 25 containing a photosensitive component is applied on the transparent planarizing layer 23. The film thickness of the blue color resist 25 is, for example, 400 nm by setting the coating rotation speed of the coating apparatus to 2000 rpm. Further, by heating the applied blue color resist 25 at a temperature of 150 ° C. or less (eg, 70 ° C.), it does not completely cure, but imparts some solvent resistance. Next, as shown in FIG. 3D, a blue color photomask 41 having a transmittance distribution 10 that can be formed in a hemispherical or parabolic convex shape is used to form a blue color resist 25. Perform pattern exposure and development. Next, thermosetting is performed at a temperature of 300 degrees or less (for example, 200 degrees), which is a temperature that does not affect the photoelectric conversion characteristics of the photodiode 22, and the blue color microlens 62 is formed. The height of the blue color microlens 62 is set lower than that of the green color microlens 61. At that time, the blue color resist 25 is removed from a place for forming the red color microlens 63.

  Next, as shown in FIG. 3E, a red color resist 26 containing a photosensitive component is applied on the transparent planarizing layer 23. The film thickness of the red color resist 26 is, for example, 600 nm by setting the coating rotation speed of the coating apparatus to 800 rpm. Further, by heating the applied red color resist 26 at a temperature of 150 degrees or less (for example, 70 degrees), the red color resist 26 is imparted with a certain degree of solvent resistance, although it is not completely cured. Next, as shown in FIG. 3F, a red color photomask 42 having a transmittance distribution 10 that can be formed in a hemispherical or parabolic convex shape is used to form a red color resist 26. Perform pattern exposure and development. Next, thermosetting is performed at a temperature of 300 degrees or less (for example, 200 degrees), which is a temperature that does not affect the photoelectric conversion characteristics of the photodiode 22, so that the red color microlens 63 is formed. The height of the red color microlens 63 is set higher than that of the green color microlens 61.

Thereby, the color microlenses 61, 62, and 63 having different heights for each color are manufactured.
FIG. 5 is a graph showing the measurement result of the quantum efficiency of each color for each wavelength of the color microlens having the same height regardless of the difference in color such as green, blue and red. FIG. 6 is a graph showing the measurement results of the quantum efficiencies of the respective colors with respect to the respective wavelengths of the color microlenses 61, 62, and 63 formed by the above-described photolithography method and having different heights for the respective colors. 5 and 6, it was confirmed that the quantum efficiency of the color microlenses having the same height was large in each color, but that the difference in quantum efficiency was reduced by adjusting the height of the color microlens. . Thereby, according to the solid-state image sensor of 1st Embodiment, it has confirmed that quantum efficiency was controllable by adjusting the height of the color microlenses 61, 62, and 63 of three colors.

(Effect of 1st Embodiment)
The invention according to the first embodiment has the following effects.
(1) The solid-state imaging device according to the first embodiment includes a plurality of transparent planarization layers 23 and a plurality of photodiodes 22 formed on a semiconductor substrate 21 on which a plurality of photodiodes 22 are arranged. The color microlenses 61, 62, 63 of colors are stacked in this order, and the heights of the color microlenses 61, 62, 63 of different colors are different for each color.

  According to such a configuration, since the color microlenses 61, 62, and 63 are used, the distance between the lens and the photodiode 22 can be shortened, and the quantum efficiency can be improved. In addition, by adjusting the height of the color microlenses 61, 62, and 63 for each color, a difference in light collection characteristics of each color can be reduced, and a difference in quantum efficiency of each color can be reduced. Thereby, it is possible to provide a solid-state imaging device capable of reducing the difference in quantum efficiency of each color while improving the quantum efficiency.

(2) In the solid-state imaging device according to the first embodiment, the color microlenses 61, 62, and 63 are formed on the microlens main body 64 disposed on the transparent planarization layer 23 and the microlens main body 64. And a convex lens portion 65. The height of the color microlenses 61, 62, and 63 is not less than 0.2 μm and not more than 0.8 μm, and the height of the convex lens portion 65 is not less than 0.1 μm and not more than 0.7 μm.
According to such a configuration, the difference in quantum efficiency of each color can be reduced more appropriately.

(3) In the method of manufacturing the solid-state imaging device according to the first embodiment, the color microlenses 61, 62, and 63 are formed by performing pattern exposure, development, and thermosetting using a color resist containing a photosensitive component. It is characterized by that.
According to such a configuration, the color microlenses 61 to 63 can be formed more easily.
(4) The manufacturing method of the solid-state imaging device according to the first embodiment uses photomasks 40, 41, and 42 having a transmittance distribution 10 that can be formed in a hemispherical or parabolic convex shape at the time of exposure. .
According to such a configuration, the lens shape can be formed more easily.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings. In addition, about the structure similar to 1st Embodiment, the same code | symbol is used and the detail is abbreviate | omitted.
FIG. 7 is an end view illustrating the method for manufacturing the solid-state imaging device according to the second embodiment.
As shown in FIG. 7, the second embodiment is different from the first embodiment in that the color microlenses 61, 62, and 63 are formed by an etching method at the time of manufacturing the solid-state imaging device.

(Production method)
The manufacturing method of the solid-state image sensor in 2nd Embodiment is demonstrated.
First, as shown in FIG. 7A, a plurality of photodiodes 22 are formed on the semiconductor substrate 21. Next, a silicon oxide film or a silicon nitrogen oxide film is formed on the semiconductor substrate 21. Next, a transparent planarization layer (PL) 23 made of a transparent resin is formed on the semiconductor substrate 21.

  Next, a green pigment dispersed resin liquid 31 not containing a photosensitive component is applied on the transparent planarizing layer 23. As the color material of the green pigment dispersion resin liquid 31, for example, pigment green (PG) 36 or PG58 and pigment yellow (PY) 150 are used, and the pigment concentration of the green pigment dispersion resin liquid 31 is 50% or more. It is preferable to adjust so that. The film thickness of the green pigment dispersion resin liquid 31 is set to 400 nm, for example, by setting the coating rotation speed of the coating apparatus to 1000 rpm. Next, the green color filter layer 35 is formed by heating at a temperature of 300 ° C. or less (for example, 200 ° C.), which is a temperature that does not affect the actual device, so as to be thermoset.

  Next, a positive resist 32 is applied on the green color filter layer 35. The film thickness of the positive resist 32 is, for example, 1000 nm by setting the coating rotation speed of the coating apparatus to 1200 rpm. Further, the positive resist 32 is heated at 90 degrees. Next, as shown in FIG. 7B, a positive resist 32 is formed using a photomask 40 for a green region having a transmittance distribution 10 that can be formed in a hemispherical or parabolic convex shape. Pattern exposure and development are performed to form a hemispherical or parabolic resist pattern. The resist pattern is a lens matrix of the green color microlens 61. Next, as shown in FIG. 7C, the green color filter layer 35 is dry-etched using a positive resist 32 patterned in a hemispherical shape or a parabolic surface as a mask, and the sample is washed with a solvent such as cyclohexanone. Thus, the green color microlens 61 is formed. At that time, the green pigment dispersed resin liquid 31 is removed from the place for forming the blue color microlens 62 and the red color microlens 63.

  Next, as shown in FIG. 7D, a blue color resist 33 containing a photosensitive component is applied on the transparent planarizing layer 23. The film thickness of the blue color resist 33 is, for example, 400 nm by setting the coating rotation speed of the coating apparatus to 1900 rpm. Further, by heating the applied blue color resist 33 at a temperature of 150 ° C. or less (eg, 70 ° C.), it does not completely cure, but imparts some solvent resistance. Next, as shown in FIG. 7E, a blue color photomask 41 having a transmittance distribution 10 that can be formed in a hemispherical or parabolic convex shape is used to form a blue color resist 33. Perform pattern exposure and development. Next, the blue color resist 33 is thermally cured at a temperature of 300 degrees or less (for example, 230 degrees), which is a temperature that does not affect the actual device, to form the blue color microlens 62. The height of the blue color microlens 62 is set lower than that of the green color microlens 61. At that time, the blue color resist 33 is removed from a place for forming the red color microlens 63.

  Next, as shown in FIG. 7F, a red color resist 34 containing a photosensitive component is applied on the transparent planarizing layer 23. The film thickness of the red color resist 34 is, for example, 600 nm by setting the coating rotation speed of the coating apparatus to 850 rpm. Further, by heating the applied red color resist 34 at a temperature of 150 ° C. or less (for example, 70 ° C.), it does not completely cure, but gives some solvent resistance. Next, as shown in FIG. 7G, a red color photomask 42 having a transmittance distribution 10 that can be formed in a hemispherical or parabolic convex shape is used to form a red color resist 34. Perform pattern exposure and development. Next, the red color resist 34 is thermally cured at a temperature of 300 degrees or less (for example, 230 degrees), which is a temperature that does not affect the actual device, to form the red color microlens 63. The height of the red color microlens 63 is set higher than that of the green color microlens 61.

Thereby, the color microlenses 61, 62, and 63 having different heights for each color are manufactured.
Other configurations are the same as those in the first embodiment.
As described above, in the second embodiment, an example in which only the green color microlens 61 is formed by dry etching is shown. However, the blue color microlens 62 and the red color microlens 63 are also formed by dry etching in the same procedure. You can also. By patterning by dry etching, the pigment-dispersed resin liquid does not need to contain a photosensitive component, and accordingly, the pigment concentration can be increased, and the color microlenses 61, 62, 63 can be made thinner.

  FIG. 5 is a graph showing the measurement result of the quantum efficiency of each color for each wavelength of the color microlens having the same height regardless of the difference in color such as green, blue and red. FIG. 8 is a graph showing the measurement results of the quantum efficiencies of the respective colors with respect to the respective wavelengths of the color microlenses 61, 62, 63 formed by the above-described dry etching method and having different heights for the respective colors. 5 and 8, the quantum efficiencies of the color microlenses having the same height were large in each color, but it was confirmed that the difference in the quantum efficiencies was reduced by adjusting the height of the color microlenses. . Thereby, according to the solid-state image sensor of 2nd Embodiment, it has confirmed that quantum efficiency was controllable by adjusting the height of the three color microlenses 61-63.

(Effect of 2nd Embodiment)
The invention according to the second embodiment has the following effects in addition to the effects of the first embodiment.
(1) In the solid-state imaging device according to the second embodiment, the color microlenses of a plurality of colors include a green color microlens 61 formed of a green pigment dispersion resin liquid 31 having PG36 or PG58 and PY150, and a green pigment The pigment concentration of the dispersed resin liquid 31 is 50% or more.
According to such a configuration, since the green pigment dispersion resin liquid 31 containing no photosensitive component is used, the pigment concentration can be increased, and the color microlenses 61, 62, and 63 can be thinned.

(2) In the method of manufacturing the solid-state imaging device according to the second embodiment, the color filter layer (green color filter layer 35) is formed on the transparent flattening layer 23 with a pigment-dispersed resin liquid that does not contain a photosensitive component. A resist is applied on the color filter layer (green color filter layer 35), pattern exposure and development are performed on the applied resist to form a resist pattern, and the color resist layer (green color filter layer is formed using the patterned resist as a mask. The color microlens 61 is formed by performing dry etching on 35).
According to such a configuration, the color microlenses 61 to 63 can be formed more easily.
(3) In the method for manufacturing a solid-state imaging device according to the second embodiment, the resist pattern is a lens matrix of a color microlens (green color microlens 61).
According to such a configuration, the lens shape can be formed more easily.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to the drawings. In addition, about the structure similar to 1st Embodiment, the same code | symbol is used and the detail is abbreviate | omitted.
FIG. 9 is an end view illustrating the method for manufacturing the solid-state imaging device according to the third embodiment.
As shown in FIG. 9, the second embodiment is formed on the semiconductor substrate 21 side at the boundary between the color microlenses 61, 62, and 63 adjacent to each other when the solid-state imaging device is manufactured, and has a refractive index of 1.4 or more. The point which forms the certain partition 53 differs from 1st Embodiment.

(Production method)
Next, the manufacturing method of the solid-state image sensor in 3rd Embodiment is demonstrated.
First, as shown in FIG. 9A, a plurality of photodiodes 22 are formed on the semiconductor substrate 21. Next, a silicon oxide film or a silicon nitrogen oxide film is formed on the semiconductor substrate 21.
Next, synthetic quartz 51 is deposited on the semiconductor substrate 21 by a physical vapor deposition (PVD) method to a thickness of about 500 nm. As the synthetic quartz 51, one having a refractive index of 1.4 or more is employed. Subsequently, a positive resist 52 is applied on the synthetic quartz 51. The film thickness of the positive resist 52 is, for example, 2000 nm by setting the coating rotation speed of the coating apparatus to 800 rpm. Next, as shown in FIG. 9B, a photomask 70 designed so that a lattice pattern with a line width of 50 nm is transferred to the semiconductor substrate 21 side of the boundary between the color microlenses 61, 62, and 63 for each color is used. Then, the positive resist 52 is exposed and developed to form a lattice-like resist pattern.

Next, as shown in FIG. 9C, the synthetic quartz 51 is dry-etched using a positive resist 52 patterned in a lattice shape as a mask, and a solvent such as cyclohexanone is used as shown in FIG. 9D. The resist is washed to form the partition 53 of the synthetic quartz 51.
Next, as shown in FIG. 9E, a transparent planarization layer (PL) 23 made of a transparent resin is formed on the semiconductor substrate 21 between the formed partition walls 53. Next, a green color resist 24 containing a photosensitive component is applied on the transparent planarizing layer 23 and the partition wall 53. As the color material of the green color resist 24, for example, pigment green (PG) 36 or PG58 and pigment yellow (PY) 150 are used, and the pigment concentration of the green color resist 24 is adjusted to be 50% or more. It is preferable. The film thickness of the green color resist 24 is set to 550 nm, for example, by setting the coating rotation speed of the coating apparatus to 1100 rpm. In addition, by heating the applied green color resist 24 at a temperature of 150 degrees or less (for example, 70 degrees), the green color resist 24 is imparted with a certain degree of solvent resistance, although it is not completely cured.

  Next, as shown in FIG. 9F, a green color photomask 40 having a transmittance distribution 10 that can be formed in a hemispherical or parabolic convex shape is used to form a green color resist 24. Perform pattern exposure and development. Next, thermosetting is performed at a temperature of 300 degrees or less (for example, 200 degrees), which is a temperature that does not affect the photoelectric conversion characteristics of the photodiode 22, and the green color microlens 61 is formed. At this time, the green color resist 24 is removed from the place for forming the blue color microlens 62 and the red color microlens 63.

  Next, as shown in FIG. 9G, a blue color resist 25 containing a photosensitive component is applied on the transparent planarizing layer 23. The film thickness of the blue color resist 25 is set to 450 nm, for example, by setting the coating rotation speed of the coating apparatus to 1900 rpm. Further, by heating the applied blue color resist 25 at a temperature of 150 ° C. or less (eg, 70 ° C.), it does not completely cure, but imparts some solvent resistance. Next, as shown in FIG. 9 (h), the blue color resist 25 is formed using a photomask 41 for a blue region having a transmittance distribution 10 that can be formed in a hemispherical or parabolic convex shape. Perform pattern exposure and development. Next, thermosetting is performed at a temperature of 300 degrees or less (for example, 200 degrees), which is a temperature that does not affect the photoelectric conversion characteristics of the photodiode 22, and the blue color microlens 62 is formed. The height of the blue color microlens 62 is set lower than that of the green color microlens 61. At that time, the blue color resist 25 is removed from a place for forming the red color microlens 63.

  Next, as shown in FIG. 9 (i), a red color resist 26 containing a photosensitive component is applied on the transparent planarizing layer 23. The film thickness of the red color resist 26 is set to 650 nm, for example, by setting the coating rotation speed of the coating apparatus to 750 rpm. Further, by heating the applied red color resist 26 at a temperature of 150 ° C. or less (for example, 70 ° C.), it does not completely cure but imparts some solvent resistance. Next, as shown in FIG. 9 (j), a red color photomask 42 having a transmittance distribution 10 that can be formed in a hemispherical or parabolic convex shape is used to form a red color resist 26. Perform pattern exposure and development. Next, thermosetting is performed at a temperature of 300 degrees or less (for example, 200 degrees), which is a temperature that does not affect the photoelectric conversion characteristics of the photodiode 22, so that the red color microlens 63 is formed. The height of the red color microlens 63 is set higher than that of the green color microlens 61.

  Thereby, the color microlenses 61, 62, and 63 having different heights for each color are manufactured.

  Table 1 shows the measurement result of the quantum efficiency with respect to the wavelength 550 nm of the green color microlens 61 having the partition wall 53. The partition wall 53 was formed using synthetic quartz 51 having a refractive index of 1.1 to 1.5. In the conventional configuration comprising a combination of a transparent microlens and a green color filter, the quantum efficiency for a wavelength of 550 nm is 77%. Therefore, the refractive index of the partition wall 53 is desirably 1.4 or more. Thereby, it has confirmed that the solid-state image sensor of 3rd Embodiment can improve quantum efficiency by having the partition 53 of refractive index 1.4 or more.

(Effect of the third embodiment)
The invention according to the third embodiment has the following effects in addition to the effects of the first embodiment.
(1) The solid-state imaging device according to this embodiment includes a partition wall 53 that is formed on the semiconductor substrate 21 side at the boundary between adjacent color microlenses 61, 62, and 63 and has a refractive index of 1.4 or more.
According to such a configuration, the quantum efficiency can be further improved.

DESCRIPTION OF SYMBOLS 10 Photomask transmittance distribution 11 Region of 20 to 25% transmittance 12 Region of 25 to 30% transmittance 13 Region of 30 to 35% transmittance 14 Region of 35 to 40% transmittance 15 Transmittance 40 to 45% Area 20 color filter array 21 semiconductor substrate 22 photodiode 23 transparent planarization layer (PL)
24 Green color resist 25 Blue color resist 26 Red color resist 31 Green pigment dispersion resin liquid 32 Positive resist 33 Blue color resist 34 Red color resist 40 Photomask for green region 41 Photomask for blue region 42 Photo for red region Mask 51 Synthetic quartz 52 Positive resist 70 Photomask

Claims (8)

A solid-state imaging device in which a transparent flattening layer and a plurality of color microlenses formed corresponding to each of the plurality of photodiodes are stacked in this order on a semiconductor substrate on which a plurality of photodiodes are arranged. And
A solid-state imaging device, wherein the color microlenses of the plurality of colors have different heights for each color. The color microlens includes a microlens main body disposed on the transparent planarization layer, and a convex lens formed on the microlens main body.
The height of the color microlens is 0.2 μm or more and 0.8 μm or less,
2. The solid-state imaging device according to claim 1, wherein a height of the convex lens portion is not less than 0.1 μm and not more than 0.7 μm. The multi-color color microlens includes a green color microlens formed of a green pigment dispersion resin liquid having PG36 or PG58 and PY150,
3. The solid-state imaging device according to claim 1, wherein the green pigment-dispersed resin liquid has a pigment concentration of 50% or more.   The solid-state imaging according to any one of claims 1 to 3, further comprising a partition wall formed on a side of the semiconductor substrate at a boundary between the color microlenses adjacent to each other and having a refractive index of 1.4 or more. element. It is a manufacturing method of the solid-state image sensing device according to any one of claims 1 to 4,
A method of manufacturing a solid-state imaging device, wherein the color microlens is formed by performing pattern exposure, development, and thermosetting using a color resist containing a photosensitive component.   6. The method of manufacturing a solid-state imaging device according to claim 5, wherein a photomask having a transmittance distribution that can be formed in a hemispherical or parabolic convex shape is used during the exposure. It is a manufacturing method of the solid-state image sensing device according to any one of claims 1 to 4,
A color filter layer is formed with a pigment-dispersed resin liquid not containing a photosensitive component on the transparent planarizing layer, a resist is applied on the formed color filter layer, and pattern exposure and development are performed on the applied resist. A method of manufacturing a solid-state imaging device, wherein the color microlens is formed by forming a resist pattern and performing dry etching on the color filter layer using the patterned resist as a mask.   The method for manufacturing a solid-state imaging device according to claim 7, wherein the resist pattern is a lens matrix of the color microlens.

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