JP2008016760A - Solid-state imaging device and manufacturing method thereof - Google Patents

Abstract

A solid-state imaging device that is highly sensitive and hardly generates line shading is realized.
A solid-state imaging device includes a plurality of photoelectric conversion elements 12 arranged in a matrix, and a plurality of color filters 8 each formed corresponding to each photoelectric conversion element 12. A plurality of microlenses 19 formed corresponding to the conversion element 12 are provided. Among the plurality of microlenses 19, each microlens 19 arranged alternately in the row direction and the column direction has a plurality of auxiliary lenses 20, and each auxiliary lens 20 is incident on each auxiliary lens 20. Light is condensed so as to enter the photoelectric conversion element 12 corresponding to the microlens 19 having the auxiliary lens 20.
[Selection] Figure 2

Description

  The present invention relates to a solid-state imaging device and a manufacturing method thereof, and more particularly to a solid-state imaging device having a microlens and a manufacturing method thereof.

  Solid-state imaging devices used for digital cameras, video cameras, and the like have been increased in pixel size and miniaturization in order to increase the resolution of the camera. The resolution of the camera is required to be further increased, and it is expected that the increase in the number of pixels and the miniaturization of the solid-state imaging device will be further accelerated.

  The opening, which is a region where the light receiving element of the solid-state image sensor contributes to photoelectric conversion, depends on the size of the solid-state image sensor and the number of pixels. For this reason, the area of the opening is limited to about 20% to 40% of the total area of the solid-state imaging device due to the increase in the number of pixels and the miniaturization of the solid-state imaging device. Since the decrease in the aperture area directly leads to a decrease in the sensitivity of the solid-state image sensor, it is common to improve the condensing efficiency by forming a condensing microlens on the light receiving element to compensate for the decrease in the aperture area. Has been done. However, a solid-state image sensor with high resolution is required, and with this, the condensing efficiency by the microlens is lowered, and the problem that sensitivity is lowered and smear is generated and noise is increased is highlighted. Has been.

  Further, line shading, which is a striped image defect, is likely to occur due to pixel miniaturization. The cause of the occurrence of line shading is stray light incident on a photoelectric conversion element (G pixel) that receives green light from a microlens formed on the photoelectric conversion element (R pixel) that receives red light, and blue light. This is because the size of the stray light incident on the photoelectric conversion element (G pixel) that receives green light from the microlens formed on the photoelectric conversion element (B pixel) that receives the green light is different. Conceivable. If the microlens condensing efficiency decreases due to pixel miniaturization and the amount of light incident on the original photoelectric conversion element decreases, the influence of the stray light component increases and line shading is likely to occur.

  In order to prevent the occurrence of line shading, it is necessary to improve the light collection efficiency of the microlens. In order to improve the condensing efficiency of microlenses, a method of condensing light incident on an ineffective area generated between microlenses on a photoelectric conversion element is known. In general, microlenses are formed using a combination of photolithographic technology using heat-sensitive resin and heat flow technology. Due to the limitations of these technologies, the microlenses arranged in a matrix form in the diagonal direction. An invalid area of about 0.5 μm is generated (see, for example, Patent Document 1). Since the light incident on the invalid region is not condensed on the photoelectric conversion element, it causes a decrease in sensitivity. Moreover, since the light incident on the invalid region enters the light shielding portion, it causes smear. As a method for preventing the generation of an ineffective area, a technique for providing a transparent resin layer in the ineffective area (see, for example, Patent Document 2) and a technique for forming a groove serving as a concave lens in a portion between microlenses are disclosed. (For example, refer to Patent Document 3).

In order to suppress the occurrence of line shading due to color mixing of incident light, it is particularly effective to increase the amount of light incident on the photoelectric conversion element that receives green light. For this reason, a technique for adjusting the amount of incident light by changing the size and height of the microlens for each color pixel has been disclosed (see, for example, Patent Document 4).
Japanese Patent No. 2776810 JP 2001-274369 A JP-A-5-27196 JP-A-9-116127

  However, since the technique of Patent Document 2 is a method based on the viscosity of the transparent resin layer, there is a problem that it is difficult to obtain a target shape. Moreover, since the technique of patent document 3 forms a groove | channel by an etching, the selective curvature control of a concave lens is difficult, the light which injects into the center part of a concave lens cannot be condensed, and the problem that incident light cannot be used effectively There is.

  Also, if the size and height of the microlens is changed to suppress the occurrence of line shading, the focal length of the microlens changes, so that incident light cannot be collected efficiently, and overall sensitivity is improved. There is a problem of lowering.

  An object of the present invention is to solve the above-mentioned conventional problems and to realize a solid-state imaging device that is highly sensitive and hardly generates line shading.

  In order to achieve the above object, according to the present invention, the solid-state imaging device includes a microlens having an auxiliary lens.

Specifically, the solid-state imaging device according to the present invention includes a plurality of photoelectric conversion elements arranged in a matrix, each formed corresponding to each photoelectric conversion element, and arranged so as to constitute a primary color Bayer array. A plurality of color filters, each of which is formed corresponding to each photoelectric conversion element, and a plurality of microlenses for condensing light on the corresponding photoelectric conversion element. Each microlens arranged in the column direction has an auxiliary lens, and each auxiliary lens has light incident on the auxiliary lens incident on a photoelectric conversion element corresponding to the microlens having the auxiliary lens. According to the solid-state imaging device of the present invention, each microlens arranged in the row direction and the column direction has an auxiliary lens, respectively. Therefore, the light incident on the gap portion between the microlenses can be condensed on the photoelectric conversion element. Therefore, it is possible to effectively use the light incident on the gap portion between the microlenses, improve the sensitivity, and reduce the occurrence of noise such as smear. Further, since the light collection efficiency to the photoelectric conversion element corresponding to the auxiliary lens is improved, the sensitivity of the pixel of a specific color can be improved. Therefore, since the influence of the stray light component can be reduced, the occurrence of line shading can be suppressed.

  In the solid-state imaging device of the present invention, the plurality of color filters are a red filter, a green filter, and a blue filter, a microlens having an auxiliary lens is a microlens corresponding to the green filter, and the auxiliary lens is In the microlens having the auxiliary lens, at least one of a portion between the microlenses adjacent in the diagonal direction and a portion between the microlens adjacent in the row direction and the microlens adjacent in the column direction It is preferable to be formed. With such a configuration, the sensitivity of the G pixel that receives green light can be made higher than that of the other pixels, so that the occurrence of line shading can be reliably suppressed.

  In the solid-state imaging device of the present invention, the plurality of color filters are a red filter, a green filter and a blue filter, and a microlens having an auxiliary lens corresponds to a microlens and a blue filter corresponding to the red filter. The auxiliary lens is a portion of the microlens having the auxiliary lens between the microlens adjacent in the diagonal direction, the microlens adjacent in the row direction, and the microlens adjacent in the column direction. It is preferable that it is formed in at least one of the intermediate portions. By adopting such a configuration, stray light components incident on the G pixel can be reduced from the R pixel that receives red light and the B pixel that receives blue light. Can be suppressed.

  In the solid-state imaging device of the present invention, each microlens has a gap between the microlenses adjacent to each other in the diagonal direction, and the microlenses adjacent to each other in the row direction and the microlenses adjacent to each other in the column direction face each other. The auxiliary lens is a part of the microlens having the auxiliary lens between the diagonally adjacent microlens, the microlens adjacent in the row direction, and the microlens adjacent in the column direction. The auxiliary lens formed in the portion between the microlenses adjacent to each other in the diagonal direction in one microlens of the plurality of microlenses having the auxiliary lens It is formed in the part between the lens and one microlens in the diagonally adjacent microlens. The auxiliary lens formed on the portion between the micro lens adjacent in the row direction and the micro lens adjacent in the column direction in one micro lens is in contact with the lens surface opposite to each other. It is preferable that the lens is formed so as to cover a part of the lens curved surface of the micro lens adjacent to the lens in the row direction and the micro lens adjacent to the column direction. With such a configuration, light incident on the auxiliary lens can be reliably incident on the photoelectric conversion element corresponding to the auxiliary lens.

  In the solid-state imaging device of the present invention, each microlens is in contact with the microlenses adjacent in the diagonal direction so that the lens curved surfaces face each other and is adjacent to the microlenses adjacent in the row direction and the microlenses adjacent in the column direction. The auxiliary lenses are arranged so as to face each other, and the auxiliary lens is formed in a portion between the micro lens having the auxiliary lens, the micro lens adjacent in the row direction, and the micro lens adjacent in the column direction, and has a plurality of auxiliary lenses The auxiliary lens formed on one of the microlenses is formed so as to cover a part of the lens curved surface of the microlens adjacent to the one microlens in the row direction and the microlens adjacent to the column direction. It is preferable.

  In the solid-state imaging device of the present invention, each microlens has a gap between the microlenses adjacent in the diagonal direction and a gap between the microlens adjacent in the row direction and the microlens adjacent in the column direction. And each auxiliary lens includes a portion between the microlenses adjacent to each other in the diagonal direction, a microlens adjacent to each other in the row direction, and a microlens adjacent to each other in the column direction. The auxiliary lens formed in the portion between the microlenses adjacent to each other in the diagonal direction in one microlens of the plurality of microlenses having the auxiliary lens is formed as one microlens. Lens formed in a portion between the microlens and one microlens in the diagonally adjacent microlens Auxiliary lenses that are in contact with each other with their lens curved surfaces facing each other and between the microlens adjacent in the row direction and the microlens adjacent in the column direction in one microlens are aligned with the one microlens in the row direction. It is preferable that the microlenses adjacent to each other and the microlenses adjacent to each other in the column direction are formed with their lens curved surfaces facing each other.

  In the solid-state imaging device of the present invention, the auxiliary lens preferably has a lens curved surface that is not convex downward. The auxiliary lens may have a planar lens surface.

  In the solid-state imaging device of the present invention, the auxiliary lens is preferably formed integrally with the microlens. With such a configuration, reflection at the interface between the auxiliary lens and the microlens can be reduced.

  In the first method for manufacturing a solid-state imaging device according to the present invention, a step of forming a plurality of microlenses arranged in a matrix on a planarization layer formed on a substrate, and the microlens are formed. After applying the lens material on the planarizing layer, the applied lens material is patterned, so that among the plurality of microlenses, the microlenses formed in the row direction and the column direction are alternately arranged in the diagonal direction. Forming an auxiliary lens forming film on at least one of a portion between adjacent microlenses and a portion between microlenses adjacent in the row direction and microlenses adjacent in the column direction; and the auxiliary lens And a step of forming an auxiliary lens by forming the curved surface by a heat flow.

  According to the first method for manufacturing a solid-state imaging device, the method includes a step of forming an auxiliary lens forming film and a step of forming the auxiliary lens by forming the auxiliary lens forming film into a curved surface by heat flow. It is possible to reliably form an auxiliary lens having a predetermined curvature at the location. Therefore, it is possible to easily realize a solid-state imaging device that is highly sensitive and hardly generates line shading.

  The second method for manufacturing a solid-state imaging device according to the present invention uses a step of applying a lens material on a planarizing layer formed on a substrate, and a gray scale mask in which the chrome layer of the mask is shaded. And a step of forming a microlens integrated with the auxiliary lens by exposing the lens material.

  According to the second method for manufacturing a solid-state imaging device, since the microlens integrated with the auxiliary lens is provided, incident light is prevented from being reflected at the interface between the auxiliary lens and the microlens. can do. Therefore, it is possible to easily realize a solid-state imaging device that is highly sensitive and hardly generates line shading.

  According to the solid-state imaging device according to the present invention, it is possible to realize a solid-state imaging device that is highly sensitive and hardly generates line shading.

(One embodiment)
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a planar configuration of a solid-state imaging device according to an embodiment. 2A to 2C are cross-sectional configurations of the semiconductor device according to the present embodiment. FIG. 2A illustrates a cross-sectional configuration along line IIa-IIa in FIG. 1, and FIG. 2B illustrates IIb-IIb in FIG. The cross-sectional structure in a line is shown, (c) has shown the cross-sectional structure in the IIc-IIc line | wire of FIG. As shown in FIGS. 1 and 2, in the solid-state imaging device of this embodiment, a plurality of photoelectric conversion elements 12 are arranged in a matrix. Further, the red (R) filter, the green (G) filter, and the blue (B) filter are arranged so as to constitute a primary color Bayer array. Thereby, G pixels that receive green light are arranged so as to form a checkered pattern, and R pixels that receive red light or B pixels that receive blue light are arranged between the G pixels.

  The solid-state imaging device of this embodiment includes a semiconductor substrate 11 made of silicon or the like, a photoelectric conversion element 12 and a transfer channel 13 formed on the semiconductor substrate 11. An insulating film 31 made of silicon oxide or the like is formed on the semiconductor substrate 11. A transfer electrode 15 is formed on the transfer channel 13 via an insulating film 31, and the transfer electrode 15 is covered with an insulating film 32. On the insulating film 32, a light shielding film 16 that covers the transfer electrode 15 and has an opening that exposes the photoelectric conversion element 12 is formed.

  A planarizing layer 33 is formed on the light shielding film 16, and a color filter 8 is formed on the planarizing layer 33. The color filter 8 includes an R filter 8A, a G filter 8B, and a B filter 8C. Is included.

  A planarizing layer 34 is formed on the color filter 8, and a microlens 19 is formed on the planarizing layer 34. In the solid-state imaging device of the present embodiment, the microlens 19 formed corresponding to the G pixel has auxiliary lenses 20 formed in the row direction, the column direction, and the diagonal direction, respectively.

  Even if the microlens 19 having a symmetrical planar shape is formed with almost no gap in the row direction and the column direction, a large gap is generated in the diagonal direction. Light incident on the gap between the lenses generated in the diagonal direction does not enter the photoelectric conversion element 12, leading to a decrease in sensitivity of the solid-state imaging element. Further, since the light incident on the gap portion enters the light shielding film 16, it causes smear.

  In the solid-state imaging device according to the present embodiment, two auxiliary lenses 20 are formed in the gap portions between the microlenses 19 generated in the diagonal direction. As shown in FIG. 2A, the two auxiliary lenses 20 formed in the gap portion are formed so as to contact each other with their lens curved surfaces facing each other at an intermediate position between the two G pixels formed in the diagonal direction. ing. Thereby, the cross section of the diagonal direction of the part which the two auxiliary lenses 20 contact becomes a V-shape convex downward. For this reason, most of the light incident on the gap portion is equally distributed to the two G pixels.

  Further, as shown in FIG. 2B, the auxiliary lens 20 formed in the row direction covers a part of the lens curved surface of the microlens 19 formed on the R pixel adjacent to the G pixel in the row direction. Is formed. In the row direction, the two microlenses 19 are in contact with each other with their lens curved surfaces facing each other, and the section in the row direction of the portion where the two microlenses 19 are in contact has a downwardly convex V shape. For this reason, the auxiliary lens 20 formed in the row direction is formed so as to fill a part of the V-shaped valley formed by the lens curved surfaces of the two microlenses 19, and is one of the light that should be incident on the R pixel. The part is focused on the G pixel.

  In FIG. 2B, the row where the G pixel and the R pixel are formed is shown, but the arrangement of the microlens 19 and the auxiliary lens 20 is also arranged for the row where the G pixel and the B pixel are formed. Are the same. Further, the cross section in the column direction is the same as the cross section in the row direction.

  As a result, part of the light that should be incident on the adjacent R and B pixels is incident on the G pixel, so that the sensitivity of the G pixel is higher than that of the R and B pixels.

  If the ratio (Gr / Gb) between the sensitivity of the Gr pixel that is the G pixel adjacent to the R pixel in the row direction and the sensitivity of the Gb pixel that is the G pixel adjacent to the B pixel in the row direction deviates from 1, the stripe shape Line shading, which is an image defect, occurs. The reason why the value of Gr / Gb deviates from 1 is considered to be stray light incident on the Gr pixel and the Gb pixel from the microlens 19 formed on the R pixel and the B pixel. Therefore, by increasing the amount of light condensed on the Gr pixel and the Gb pixel, the influence of stray light on the Gr pixel and the Gb pixel becomes relatively small, and the value of Gr / Gb can be made close to 1. it can.

  The solid-state imaging device of the present embodiment condenses the light incident on the gap between the microlenses 19 on the G pixel, and also condenses a part of the light that should be incident on the R pixel and the B pixel on the G pixel. ing. Thereby, since the sensitivity of G pixel (Gr pixel and Gb pixel) can be raised, the ratio of the stray light which G pixel injects relatively falls. As a result, the value of Gr / Gb can be made close to 1, so that the occurrence of line shading can be reduced.

  In the present embodiment, the structure for collecting incident light on the G pixel has been described. However, if the auxiliary lens 20 is formed on the microlens 19 corresponding to the B pixel and R pixel, the incident light is collected on the B pixel and R pixel. be able to. When incident light is collected on the B pixel and R pixel, stray light from the B pixel and R pixel to the G pixel can be reduced. Therefore, the effect of reducing line shading can be obtained in the same manner as when incident light is collected on the G pixel.

  In the present embodiment, the auxiliary lens 20 is formed in eight directions so as to surround the microlens 19 corresponding to the G pixel, but the auxiliary lens 20 is not formed in the row direction and the column direction, but only in the diagonal direction. The auxiliary lens 20 may be formed. Also in this case, since the light incident on the gap portion between the microlenses 19 can be incident on the G pixel, the sensitivity of the G pixel can be improved. On the other hand, the auxiliary lens 20 may be formed only in a portion overlapping the microlens 19 corresponding to the R pixel and the B pixel without forming the auxiliary lens 20 in the diagonal gap portion of the microlens 19. Also in this case, the effect of improving the sensitivity of the G pixel and reducing the occurrence of line shading can be obtained.

  Further, the auxiliary lens 20 transmits at least one of the light that enters the gap portion between the microlenses 19 and a part of the light that should enter the microlens corresponding to the R pixel and the B pixel adjacent to the G pixel to G. What is necessary is just to be able to focus on a pixel. Therefore, the size, shape, quantity, and the like of the auxiliary lens 20 may be appropriately changed according to the interval and shape of the microlenses 19.

  Regarding the auxiliary lens provided in the diagonal direction of the G pixel, even if the surface of the auxiliary lens has a convex curvature upward in the diagonal section connecting the two G pixels, the shape becomes a flat surface. It may be. Further, even in a cross section perpendicular to the diagonal line connecting the two G pixels, the surface of the auxiliary lens may have a shape with a curvature or a shape with a flat surface.

  Regarding the auxiliary lens provided in the row direction and the column direction of the G pixel, even if the surface of the auxiliary lens has a curvature in the cross section in the row direction and the column direction of the G pixel, the shape is a plane. There may be. Further, even in a cross section perpendicular to the row direction and the cross section perpendicular to the column direction of the G pixel, the surface of the auxiliary lens may have a curved shape or a flat shape.

  Below, the manufacturing method of the solid-state image sensor concerning this embodiment is explained with reference to drawings. 3 and 4 show the manufacturing process of the solid-state imaging device according to the present embodiment. FIG. 3 shows the sections taken along the line IIa-IIa in FIG. 1 in the order of steps, and FIG. 4 shows the section taken along the line IIb-IIb in FIG. Are shown in the order of steps.

  First, as shown in FIGS. 3A and 4A, a photoelectric conversion element 12, a transfer channel 13, a transfer electrode 15 and the like are formed on a semiconductor substrate 11 according to a conventional method, and then flattened on the semiconductor substrate 11. The formation layer 33 is formed. Subsequently, the color filter 8 and the planarizing layer 34 are sequentially formed on the planarizing layer 33. Thereafter, a lens material is spin-coated on the planarizing layer 34 and patterned by photolithography to form a rectangular microlens forming film 19A.

  Next, as shown in FIGS. 3 (b) and 4 (b), from a acrylic resin having a diameter of 2 μm to 3 μm using a method of fluidizing the microlens forming film 19A by heating it to a softening temperature or higher. A microlens 19 is formed. At this time, as shown in FIG. 3B, a gap portion is generated between the microlenses 19 in the diagonal direction.

  Next, after forming the microlens 19 as shown in FIG. 3C and FIG. 4C, the same acrylic resin as the microlens material is spin-coated so as to cover the microlens 19 to form a film. A resin film having a thickness of 0.4 to 1 μm is formed. Subsequently, a rectangular auxiliary lens forming film 20A is formed by patterning by photolithography.

  The size of the auxiliary lens forming film 20A may be appropriately selected depending on the size and curvature of the auxiliary lens 20 to be formed. For example, the size may be about 1/6 of the diameter of the microlens. Further, when the light is condensed on the G pixel, a portion of about two-thirds of the auxiliary lens size is formed on the G pixel so as to overlap the micro lens.

  Next, as shown in FIGS. 3D and 4D, heat treatment is performed at 140 ° C. to 180 ° C. for 5 to 10 minutes, and the auxiliary lens forming film 20A is formed into a lens shape by heat flow. Thereafter, heat treatment is performed at 150 ° C. to 240 ° C. for 5 minutes to 10 minutes, and thermosetting is performed.

(First Modification of One Embodiment)
Below, the 1st modification of one Embodiment is demonstrated with reference to drawings. 5A and 5B show a solid-state imaging device according to a first modification of one embodiment. FIG. 5A shows a cross-sectional configuration corresponding to the line IIa-IIa in FIG. 1, and FIG. 1 shows a cross-sectional configuration corresponding to line IIb-IIb. In FIG. 5, the same components as those of FIG.

  As shown in FIG. 5, the solid-state imaging device of this modification example has an anisotropy in the planar shape of the microlens 19 by adjusting the thermal softening temperature or the like when the microlens 19 is formed, and the diagonal direction In FIG. 5, no gap portion is formed between the two microlenses 19. Also in this case, if the auxiliary lens 20 is formed in the row direction and the column direction of the microlens 19 corresponding to the G pixel, if the sensitivity of the G pixel is made higher than that of the R pixel and the B pixel, the occurrence of line shading is generated. Can be suppressed.

(Second Modification of One Embodiment)
Below, the 2nd modification of one Embodiment is demonstrated with reference to drawings. 6A and 6B are solid-state imaging devices according to a second modification of the embodiment, FIG. 6A shows a cross-sectional configuration corresponding to the IIa-IIa line in FIG. 1, and FIG. 1 shows a cross-sectional configuration corresponding to line IIb-IIb. In FIG. 6, the same components as those of FIG.

  As shown in FIG. 6, in the solid-state imaging device of this modification, the curvature of the microlens 19 is large, and gap portions are generated not only in the diagonal direction but also in the row direction and the column direction. In this case, the auxiliary lens 20 formed in the row direction and the column direction of the micro lens 19 corresponding to the G pixel can be formed so as not to overlap with the micro lens 19 corresponding to the adjacent R pixel and B pixel. . Even in this case, the sensitivity of the G pixel can be improved and the occurrence of line shading can be suppressed.

  Also in this case, the auxiliary lens 20 may be formed so as to partially overlap the microlens 19 corresponding to the R pixel and the B pixel, as in the first embodiment.

(Third Modification of One Embodiment)
Below, the 3rd modification of one Embodiment is demonstrated with reference to drawings. 7A and 7B are solid-state imaging devices according to a third modification of the embodiment, FIG. 7A shows a cross-sectional configuration corresponding to the IIa-IIa line in FIG. 1, and FIG. The cross-sectional structure corresponding to the IIb-IIb line | wire is shown. In FIG. 7, the same components as those in FIG.

  As shown in FIG. 7, in the solid-state imaging device of this modification, a microlens and an auxiliary lens are collectively formed. For this reason, since the interface between the microlens and the auxiliary lens can be completely eliminated, reflection at the interface can be reduced.

  Below, the manufacturing method of the solid-state image sensor of this modification is demonstrated. 8 and 9 show a method for manufacturing a solid-state imaging device according to this modification. FIGS. 8A and 8B show the cross-sectional structure taken along the line IIa-IIa in FIG. a) and (b) show the cross-sectional structure taken along line IIb-IIb in FIG.

  First, as shown in FIGS. 8A and 9A, an acrylic microlens material is spin-coated on the flat film 34 to form a microlens formation film 19B. Subsequently, exposure is performed using a gray scale mask 35 in which the chrome layer of the mask is shaded.

  As the gray scale mask 35, a mask having a light transmission distribution as shown in FIGS. 8C and 9C is used.

  Accordingly, as shown in FIGS. 8B and 9B, the microlens 19 and the auxiliary lens 20 having a pattern corresponding to the light transmittance distribution of the gray scale mask can be integrally formed. In this example, the microlens and the auxiliary lens have the same shape as the one example, but the microlens and the auxiliary lens having the same shape as the first modification of the embodiment or the second modification of the embodiment are used. It may be formed. By the manufacturing method of this modification, the interface between the microlens and the auxiliary lens can be completely eliminated, so that reflection due to the interface can be reduced. In addition, this manufacturing method can reduce the number of steps. Although the microlens material is acrylic, it need not have heat flow properties.

  The solid-state imaging device according to the present invention can realize a solid-state imaging device that is highly sensitive and hardly generates line shading, and is particularly useful as a microlens constituting the solid-state imaging device and a method thereof.

It is a top view which shows the solid-state image sensor which concerns on one Embodiment of this invention. (A)-(c) shows the solid-state image sensor which concerns on one Embodiment of this invention, (a) is sectional drawing in the IIa-IIa line | wire of FIG. 1, (b) is IIb-IIb of FIG. It is sectional drawing in a line, (c) is sectional drawing in the IIc-IIc line | wire of FIG. It is sectional drawing which shows the manufacturing method of the solid-state image sensor which concerns on one Embodiment of this invention in process order. It is sectional drawing which shows the manufacturing method of the solid-state image sensor which concerns on one Embodiment of this invention in process order. (A) And (b) shows the solid-state image sensor which concerns on the 1st modification of one Embodiment of this invention, (a) is sectional drawing in the IIa-IIa line | wire of FIG. 1, (b) is a figure. It is sectional drawing in the IIb-IIb line | wire of 1. FIG. (A) And (b) shows the solid-state image sensor concerning the 2nd modification of one Embodiment of this invention, (a) is sectional drawing in the IIa-IIa line | wire of FIG. 1, (b) is a figure. It is sectional drawing in the IIb-IIb line | wire of 1. FIG. (A) And (b) shows the solid-state image sensor which concerns on the 3rd modification of one Embodiment of this invention, (a) is sectional drawing in the IIa-IIa line | wire of FIG. 1, (b) is a figure. It is sectional drawing in the IIb-IIb line | wire of 1. FIG. (A) And (b) is sectional drawing which shows the manufacturing method of the solid-state image sensor concerning the 3rd modification of one Embodiment of this invention in order of a process, (c) is a graph which shows the light transmission characteristic of a gray scale mask It is. (A) And (b) is sectional drawing which shows the manufacturing method of the solid-state image sensor concerning the 3rd modification of one Embodiment of this invention in order of a process, (c) is a graph which shows the light transmission characteristic of a gray scale mask It is.

Explanation of symbols

8 Color filter 8A Red filter 8B Green filter 8C Blue filter 11 Semiconductor substrate 12 Photoelectric conversion element 13 Transfer channel 15 Transfer electrode 16 Light shielding film 19 Microlens 19A Microlens formation film 19B Microlens formation film 20 Auxiliary lens 20A Auxiliary lens formation film 31 Insulating film 32 Insulating film 33 Flattening layer 34 Flattening layer 35 Gray scale mask

Claims (11)

A plurality of photoelectric conversion elements arranged in a matrix;
A plurality of color filters, each of which is formed corresponding to each of the photoelectric conversion elements, and arranged to constitute a primary color Bayer array;
Each includes a plurality of microlenses formed corresponding to each of the photoelectric conversion elements, and condensing light on the corresponding photoelectric conversion elements,
Among the plurality of microlenses, each microlens arranged every other row direction and column direction has an auxiliary lens, respectively.
Each of the auxiliary lenses collects light incident on the auxiliary lens so as to be incident on the photoelectric conversion element corresponding to the microlens having the auxiliary lens. The plurality of color filters are a red filter, a green filter, and a blue filter,
The microlens having the auxiliary lens is a microlens corresponding to the green filter,
In the microlens having the auxiliary lens, the auxiliary lens includes a portion between the microlenses adjacent in the diagonal direction, and a portion between the microlens adjacent in the row direction and the microlens adjacent in the column direction. The solid-state imaging device according to claim 1, wherein the solid-state imaging device is formed on at least one of them. The plurality of color filters are a red filter, a green filter, and a blue filter,
The micro lens having the auxiliary lens is a micro lens corresponding to the red filter and a micro lens corresponding to the blue filter,
In the microlens having the auxiliary lens, the auxiliary lens includes a portion between the microlenses adjacent in the diagonal direction, and a portion between the microlens adjacent in the row direction and the microlens adjacent in the column direction. The solid-state imaging device according to claim 1, wherein the solid-state imaging device is formed on at least one of them. Each of the microlenses has a gap between the microlenses adjacent in the diagonal direction and is arranged so that the curved surfaces of the microlenses adjacent in the row direction and the microlenses adjacent in the column direction are opposed to each other. ,
The auxiliary lens is a portion between the microlenses adjacent in the diagonal direction and the portion between the microlenses adjacent in the row direction and the microlenses adjacent in the column direction in the microlens having the auxiliary lens. Formed,
The auxiliary lens formed in a portion between the microlenses adjacent in the diagonal direction in one microlens among the plurality of microlenses having the auxiliary lens is a microlens adjacent in the diagonal direction to the one microlens. An auxiliary lens formed in a portion of the lens between the one microlens and the lens curved surface facing each other;
The auxiliary lens formed in the portion between the micro lens adjacent in the row direction and the micro lens adjacent in the column direction in the one micro lens is the micro lens and column adjacent in the row direction of the one micro lens. The solid-state imaging device according to claim 1, wherein the solid-state imaging element is formed so as to cover a part of a lens curved surface of a microlens adjacent in a direction. Each of the microlenses is arranged so as to be in contact with the diagonally adjacent microlens with the lens curved surface facing each other and with the microlens adjacent in the row direction and the microlens adjacent in the column direction facing the lens curved surface. And
The auxiliary lens is formed in a portion between the micro lens having the auxiliary lens, the micro lens adjacent in the row direction, and the micro lens adjacent in the column direction,
The auxiliary lens formed on one microlens of the plurality of microlenses having the auxiliary lens is one of lens curved surfaces of the microlens adjacent to the one microlens in the row direction and the microlens adjacent to the column direction. The solid-state imaging device according to claim 1, wherein the solid-state imaging device is formed so as to cover a portion. Each of the microlenses is arranged so as to have a gap between the microlenses adjacent in the diagonal direction and a gap between the microlens adjacent in the row direction and the microlens adjacent in the column direction,
Each of the auxiliary lenses includes a portion between the microlenses adjacent in the diagonal direction and a portion between the microlenses adjacent in the row direction and the microlenses adjacent in the column direction in the microlens having the auxiliary lens. Formed into
The auxiliary lens formed in a portion between the microlenses adjacent to each other in the diagonal direction in one microlens among the plurality of microlenses having the auxiliary lens is adjacent to the one microlens in the diagonal direction. Auxiliary lens formed in a portion between the one micro lens in the micro lens and the lens curved surface facing each other,
The auxiliary lens formed in the portion between the micro lens adjacent in the row direction and the micro lens adjacent in the column direction in the one micro lens is the micro lens and column adjacent in the row direction of the one micro lens. The solid-state imaging device according to claim 1, wherein the microlenses adjacent to each other are formed so that their lens curved surfaces face each other.   The solid-state imaging device according to claim 1, wherein the auxiliary lens has a lens curved surface that is not convex downward.   The solid-state imaging device according to claim 1, wherein the auxiliary lens has a planar lens surface.   The solid-state imaging device according to claim 1, wherein the auxiliary lens is formed integrally with the microlens. Forming a plurality of microlenses arranged in a matrix on a planarization layer formed on a substrate;
After applying the lens material on the planarizing layer on which the microlenses are formed, the applied lens material is patterned to form every other microlens in the row direction and the column direction. An auxiliary lens forming film on at least one of a portion between the microlenses adjacent in the diagonal direction and a portion between the microlens adjacent in the row direction and the microlens adjacent in the column direction in the microlens Forming a step;
Forming the auxiliary lens by forming the auxiliary lens forming film into a curved surface by heat flow. Applying a lens material on the planarization layer formed on the substrate;
And a step of forming a microlens integrated with the auxiliary lens by exposing the lens material using a grayscale mask in which the chrome layer of the mask is shaded. Manufacturing method.

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