JP2022019233A - Solid-state image sensor and manufacturing method thereof - Google Patents

Abstract

To provide a solid-state image sensor equipped with a lens array composed of a semi-cylindrical microlens that has no disturbance in the cross-sectional shape of the microlens even when the pitch of the semi-cylindrical microlens in a direction orthogonal to the stretching direction of the semi-cylindrical microlens is 10 μm to 20 μm.SOLUTION: A solid-state image sensor 10 includes a semiconductor substrate for a solid-state image sensor in which a plurality of photodiodes 4 are formed in an XY matrix, and a lens array 8 composed of a plurality of semi-cylindrical microlenses 1 formed so as to overlap the photodiode in a plan view, and the semi-cylindrical microlens of the lens array are stretched corresponding to the photodiode formed in the XY matrix and is provided parallel to each other at a constant pitch, and the formation pitch in the Y or X direction of the microlens is 10 μm to 20 μm, and the height is 1.5 μm to 3.0 μm.SELECTED DRAWING: Figure 1

Description

The present invention relates to a solid-state image sensor using a microlens. More specifically, the present invention relates to a solid-state image sensor using a semi-cylindrical microlens.

The solid-state image sensor is a semiconductor device that converts an image formed on the surface of a solid-state image sensor through a lens system into an electric signal using a photoelectric conversion element such as a photodiode. The solid-state image sensor is a semiconductor device manufactured by processing a silicon wafer into a wafer, and photoelectric conversion elements are arranged in a matrix. A multilayer wiring layer is formed around the upper part of these photoelectric conversion elements. The uppermost layer of the surface of such a semiconductor element is covered with a passivation film, and has a structure that prevents moisture and the like from entering the semiconductor element. An on-chip color filter for color separation is formed on the surface of such a solid-state image sensor, and light around the photoelectric conversion element is also taken into the photoelectric conversion element on the upper layer to improve the sensitivity. Microlenses are usually formed.

The form of the microlens is usually hemispherical, but depending on the form of the solid-state image sensor, a semi-cylindrical microlens may be used. A semicircular microlens is a microlens that is elongated in the longitudinal direction with long lenses adjacent to each other in parallel, and is formed in a plane orthogonal to the longitudinal direction of one semicircular microlens. Although the cross-sectional shape is semicircular, it has the characteristic of being able to form an aspherical surface. Hereinafter, the semi-cylindrical microlens will be referred to as a semi-cylindrical microlens, or simply a microlens.

Since this semi-cylindrical microlens can be an aspherical lens, it is possible to manufacture a microlens having high focusing efficiency as a lens.

Japanese Unexamined Patent Publication No. 2005-62692 Japanese Unexamined Patent Publication No. 2008-05395

Such a semi-cylindrical microlens is provided with a plurality of semi-cylindrical microlenses connected in parallel in a direction orthogonal to the longitudinal direction of the semi-cylindrical microlens.
FIG. 3A shows an example of a cross-sectional view of the solid-state image pickup device 10-1 on a plane orthogonal to the stretching direction of the microlens 1-1. When the pitch (similar to the width of the semi-cylindrical microlens) in the direction orthogonal to the longitudinal direction is less than 10 μm, the cross-sectional shape of the semi-cylindrical microlens 1-1 is normal to be semi-cylindrical. It has a cross-sectional shape. In this case, the light (incident light) 5 incident on the microlens 1-1 passes through the flattening layer 2 and the color filter 3-1 and is focused on the surface of the photodiode 4 as designed.

However, when the pitch in the direction orthogonal to the longitudinal direction is 10 μm to 20 μm, the lens shape is formed in the central portion of the cross section of the microlens 1 ′, as illustrated in the cross-sectional view of the solid-state image sensor 10 ′ in FIG. 3 (b). In some cases, the disordered portion 6 of the lens is formed. The disordered portion 6 of the lens shape is a phenomenon in which a dent is generated in the central portion in the cross section of the microlens 1'. When such a disorder of the surface shape of the lens occurs, the normal function as a lens is lost. Therefore, as illustrated as the incident light 5', the light focused by the lens is disturbed, and the light is not normally focused on the surface of the photodiode 4. The flattening layer 2 and the photodiode 4 are the same as those in FIG. 3 (a), but the microlens 1'has a pitch (10 μm) larger than the pitch (less than 10 μm) of the color filter 3-1 in FIG. 3 (a). It is a large semi-cylindrical microlens formed corresponding to the color filter 3'formed by (~ 20 μm).

As a prior art closest to the technique for solving the problem of such a semi-cylindrical microlens, for example, Patent Document 1 discloses a liquid crystal display device that does not use a color filter. In this technology, a semi-cylindrical microlens is equipped with prism structures having angles of red, green, and blue, respectively, so that the light incident on those prism structures is separated by the action of the prism and colored. It is a technology that produces red, green, and blue without using a filter.

Further, Patent Document 2 discloses a stereoscopic image display device using a semi-cylindrical microlens. In this technology, as a means of creating the parallax of an image that enters both eyes, which is necessary to create a stereoscopic effect, two microlens sheets having different focal lengths are used in different longitudinal directions of the semi-cylindrical microlenses. The feature is that it is created by arranging it so that it forms a certain angle.

These techniques are related to the semi-cylindrical microlens, but when the pitch of the semi-cylindrical microlens in the direction orthogonal to the stretching direction of the semi-cylindrical microlens is 10 μm to 20 μm, This is different from the technology for solving the disorder (dent) of the lens shape that occurs in the center of the cross-sectional shape of the microlens.

In view of the above circumstances, in the present invention, even if the pitch of the semi-cylindrical microlens in the direction orthogonal to the stretching direction of the semi-cylindrical microlens is 10 μm to 20 μm, the cross-sectional shape of the microlens is disturbed. An object of the present invention is to provide a solid-state imaging device provided with a lens array composed of a semi-cylindrical microlens.

As a means for solving the above problems, the first aspect of the present invention is a semiconductor substrate for a solid-state image sensor in which a plurality of photodiodes are formed in an XY matrix, and a plurality of photodiodes formed so as to overlap the photodiodes in a plan view. A solid-state image sensor equipped with a lens array consisting of semi-cylindrical microlenses.
Each semi-cylindrical microlens constituting the lens array is extended corresponding to the X or Y direction of the photodiode formed in the XY matrix, and is provided in parallel with each other at a constant pitch.
The semi-cylindrical microlens is a solid-state imaging device characterized in that the formation pitch in the width direction is 10 μm to 20 μm and the height is 1.5 μm to 3.0 μm.

Further, the present invention includes a semiconductor substrate for a solid-state image sensor in which a plurality of photodiodes are formed in an XY matrix, and a lens array composed of a plurality of semi-cylindrical microlenses formed so as to overlap the photodiodes in a plan view. It is a solid-state image sensor
Each semi-cylindrical microlens constituting the lens array is extended corresponding to the X or Y direction of the photodiode formed in the XY matrix, and is provided in parallel with each other at a constant pitch.
The formation pitch of the semi-cylindrical microlens in the width direction is 10 μm to 20 μm, and the height is 1.5 μm to 3.0 μm.
Between the semi-cylindrical microlens and the semiconductor substrate, the semi-cylindrical microlens passes through the midpoint of the width of the semi-cylindrical microlens and overlaps with the center line extending in the longitudinal direction. It is a solid-state image pickup device characterized by having a pattern made of a transparent layer having a width of 30% to 50% and a height of 50% to 70%.

Further, the refractive index of the transparent layer is lower than that of the semi-cylindrical microlens.

Further, the second aspect of the present invention is
A method for manufacturing a lens array of a solid-state image sensor.
The step of forming the resin layer to be the semi-cylindrical microlens, and
The process of forming a pattern consisting of a transparent layer and
The process of forming a photosensitive resin pattern that serves as a base for the semi-cylindrical microlens, and
The step of forming the matrix of the semi-cylindrical microlens by heat-treating the photosensitive resin pattern, and
The process includes a step of removing the pattern consisting of the mother mold of the semi-cylindrical microlens and the transparent layer by dry etching, and transferring the semi-cylindrical microlens to the resin layer to be the microlens.
The center line extending in the longitudinal direction through the midpoint of the width of the semi-cylindrical microlens is located at a position overlapping the center line extending in the longitudinal direction through the midpoint of the width of the pattern made of the transparent layer. It is a method for manufacturing a lens array, which is characterized by being formed.

Further, the step of forming the resin layer to be the semi-cylindrical microlens, and
The process of forming a pattern consisting of a transparent layer and
The step of forming a photosensitive resin pattern to be a semi-cylindrical microlens, and
It comprises a step of forming the semi-cylindrical microlens by heat-treating the photosensitive resin pattern.
The center line extending in the longitudinal direction through the midpoint of the width of the semi-cylindrical microlens is located at a position overlapping the center line extending in the longitudinal direction through the midpoint of the width of the pattern made of the transparent layer. It is a method for manufacturing a lens array, which is characterized by being formed.

According to the solid-state image pickup device of the present invention, a plurality of photodiodes are stretched along the photodiodes formed in the X-direction or the Y-direction of the semiconductor substrate for a solid-state image pickup device formed in an XY matrix, and are parallel to each other. It is equipped with a semi-cylindrical microlens provided in conjunction with each other. The formation pitch of these semi-cylindrical microlenses in the Y direction or the X direction is 10 μm to 20 μm, and the height is 1.5 μm to 3.0 μm. As a result, the lens shape is not disturbed centering on the highest part of the cross section in the plane orthogonal to the longitudinal direction of the semi-cylindrical microlens. Therefore, the light collection performance of the semi-cylindrical microlens does not deteriorate.

Further, according to the solid-state image sensor of the present invention, between the semi-cylindrical microlens and the semiconductor substrate is 30% to 50% of the width of the semi-cylindrical microlens along the X direction or the Y direction. A transparent layer with a width of 50% to 70% of the height of a semi-cylindrical microlens is provided. Therefore, the lens shape is not disturbed centering on the highest part of the cross section in the plane orthogonal to the longitudinal direction of the semi-cylindrical microlens. Therefore, the light collection performance of the semi-cylindrical microlens does not deteriorate.

According to the method for manufacturing a lens array of the present invention, the solid-state image pickup device of the present invention can be provided by increasing the pattern forming step by one step without reviewing the heat flow step of the resin.

The cross-sectional explanatory view explaining the semi-cylindrical microlens of the solid-state image sensor of this invention. The cross-sectional explanatory view explaining the manufacturing method of the semi-cylindrical microlens of the solid-state image sensor of this invention. A cross-sectional explanatory view illustrating a problem of a semi-cylindrical microlens of a conventional solid-state image sensor.

<First embodiment>
The solid-state image sensor according to the first embodiment of the present invention will be described with reference to FIG. 1 (a). (Solid image sensor)
The solid-state image sensor 10 of the present invention includes a semiconductor substrate for a solid-state image sensor in which a plurality of photodiodes 4 are formed in an XY matrix, and a plurality of semi-cylindrical micros formed so as to overlap the photodiode 4 in a plan view. It is a solid-state image pickup device including a lens array 8 composed of a lens 1.

Here, the semi-cylindrical microlens 1 refers to each semi-cylindrical microlens. Further, the lens array 8 refers to a lens array 8 in which a plurality of semi-cylindrical microlenses 1 are provided at a constant pitch in a direction orthogonal to the longitudinal direction thereof on a plane on which the microlens 1 is formed. .. The semi-cylindrical microlenses 1 may be overlapped with each other at the ends, or may be arranged at a constant pitch in a separated and separated state. Further, the long sides of adjacent microlenses 1 may be arranged in parallel.

The lens array 8 composed of each semi-cylindrical microlens 1 is extended along either the X direction or the Y direction of the photodiode 4 formed in an XY matrix, and is provided parallel to each other at a constant pitch. ing. That is, a lenticular lens having a finer size than the lenticular lens used for stereoscopic viewing of printed matter is provided corresponding to the photodiode 4 formed in the X direction and the Y direction. The lenticular lens is a sheet-shaped lens in which a plurality of lenticular or semi-cylindrical lenses are formed at a constant pitch in a direction orthogonal to the longitudinal direction thereof. The formation pitch of the semi-cylindrical lens used for changing the image changes depending on the stereoscopic view of the printed matter and the viewing angle is usually 15 (Line / inch) to 150 (Line / inch) (about 1.7 mm to about). 17.0 mm).

The formation pitch of the lens array 8 made of the semi-cylindrical microlens 1 used in the solid-state image pickup device of the present invention in the Y direction or the X direction is 10 μm to 20 μm, and the height is 1.5 μm to 3.0 μm. The feature is that. Even in the lens array 8 composed of the semi-cylindrical microlens 1 having such a pitch and height, the lens shape such as a recess generated around the thickest portion of the semi-cylindrical microlens 1 No turbulence has occurred.

(Manufacturing method of semi-cylindrical microlens)
The solid-state image sensor described above can be obtained by the method for manufacturing a semi-cylindrical microlens according to the embodiment of the present invention. Hereinafter, a method for manufacturing a semi-cylindrical microlens according to an embodiment of the present invention will be described. As a configuration other than the semi-cylindrical microlens, as shown in FIG. 1A, a functional layer such as a flattening layer is formed on a semiconductor substrate in which the photodiode 4 is formed in an XY matrix shape. There is. A color filter 3 is formed on the surface of the functional layer, and a flattening layer 2 is further formed on the surface of the color filter 3. The formation of the functional layer is arbitrary and is not shown in FIG. 1 (a).

The method for manufacturing a semi-cylindrical microlens includes a step of forming a resin layer to be a semi-cylindrical microlens, a step of forming a pattern consisting of a transparent layer, and a photosensitivity to be a mother mold of the semi-cylindrical microlens. It consists of a step of forming a sex resin pattern, a step of forming a master mold of the semi-cylindrical microlens by heat-treating the photosensitive resin pattern, and a master mold and a transparent layer of the semi-cylindrical microlens. The present invention comprises a step of removing the pattern by dry etching and transferring the semi-cylindrical microlens to a resin layer to be a microlens.

Hereinafter, a method for manufacturing a semi-cylindrical microlens of the present invention will be described with reference to FIG. 2 (A).
(Step of forming a resin layer to be a semi-cylindrical microlens)
In the step of forming the resin layer to be a semi-cylindrical microlens, first, a semiconductor substrate in which the photodiode 4 is arranged in an XY matrix is prepared (see FIGS. 2A and 2A), and the photodiode 4 is placed on the semiconductor substrate. The color filter 3 is formed in alignment with the photodiode (see FIGS. 2A and 2B). Next, the flattening layer 2 is formed on the color filter 3 (see FIGS. 2A and 2C). Next, the lens resin layer 9 is formed on the surface of the flattening layer 2 (see FIGS. 2A and 2D). The lens resin layer 9 is a resin layer that becomes a semi-cylindrical microlens 1.

The material of the lens resin layer 9 is not particularly limited as long as it is a transparent resin. For example, polymethylmethacrylate resin (PMMA, Polymethyl methylate) can be preferably used.
As a method for forming the lens resin layer 9, a coating liquid prepared by a transparent resin and a solvent thereof or the like can be used, and various coating methods can be used for coating. For example, a spin coating method, a roll coating method, an offset transfer method, a screen printing method, and the like can be mentioned.

(Step of forming a pattern consisting of a transparent layer)
In the step of forming the pattern made of the transparent layer, first, the pattern made of the transparent layer 7 is formed on the resin layer (lens resin layer 9) to be a semi-cylindrical microlens (FIGS. 2A and 2E). )reference).
The width of the pattern composed of the transparent layer 7 is 30% to 50% of the width of the semi-cylindrical microlens, and the height (or thickness) of the pattern is 50% to 70% of the semi-cylindrical microlens. .. If the width of the pattern composed of the transparent layer 7 is less than 30% of the width of the semi-cylindrical microlens, there is a high possibility that the effect of improving the concave microlens shape will not be exerted. On the other hand, if it exceeds 50%, it tends to affect not only the concave portion but also the film thickness of the entire microlens. Further, when the height of the pattern made of the transparent layer is less than 50% of that of the semi-cylindrical microlens, the film thickness of the concave shape cannot be compensated and the concave shape may remain. Further, when it exceeds 70%, only a part of the microlens tends to be convex.

A photoelectric conversion element such as a photodiode 4 is formed on a semiconductor substrate in an XY matrix shape, and a semi-cylindrical microlens is formed corresponding to these photoelectric conversion elements. For example, it is formed so that the longitudinal direction of the semi-cylindrical microlens is parallel to the X direction, corresponding to the photoelectric conversion element formed in the X direction of the semiconductor substrate. In the Y direction, semi-cylindrical microlenses of the same form are formed in parallel and in connection with each other corresponding to the position where the photoelectric conversion element is formed. The X direction and the Y direction may be interchanged.

The pattern made of the transparent layer 7 and the semi-cylindrical microlens are parallel in the longitudinal direction (stretching direction). The pattern made of the transparent layer passes through a substantially midpoint in the width direction orthogonal to the stretching direction of the semi-cylindrical microlens. Further, it is preferable that the longitudinal center line of the pattern made of the transparent layer coincides with the longitudinal center line of the semi-cylindrical microlens. By doing so, the cross-sectional shape in the plane orthogonal to the longitudinal direction of the finally formed semi-cylindrical microlens becomes a symmetrical shape. Further, since the thickness and width of the pattern composed of the transparent layer 7 are within the above-mentioned numerical range, it is possible to suppress the shape near the lens apex from being disturbed even with a large semi-cylindrical microlens, which is excellent. It is a lens with light-collecting performance.

The material of the transparent layer 7 is preferably the same material as the resin layer that becomes the semi-cylindrical microlens underneath, but any transparent resin having a refractive index equivalent to that of the resin layer can be used. ..

For example, polymethylmethacrylate resin (PMMA, Polymethylmethacrylicate), polymethylpentene (PMP, Polymethylpentene), allyldiglycolcarbonate (CR-39), MS resin (methylmethacrylate / styrene copolymer), acryliconitrile styrene resin (AS resin). ), Polycarbonate resin (PC), polyethylene resin (PS) and the like.

The method of forming the pattern composed of the transparent layer 7 is not particularly limited. For example, a photosensitive transparent resin coating liquid using the above-mentioned transparent resin material such as polymethyl methacrylate resin is prepared, and the coating liquid is used for patterning by a photolithography method to form a pattern consisting of a transparent layer. Can be formed. The midpoint of the width in the direction orthogonal to the extending direction of the pattern made of the transparent layer is formed so as to coincide with the midpoint of the width of the semi-cylindrical microlens. However, a semi-cylindrical microlens has not been formed at this stage. Therefore, it may be formed corresponding to a photoelectric conversion element such as a photodiode arranged in an XY matrix on a semiconductor substrate.

(Step of forming a photosensitive resin pattern that serves as a base for a semi-cylindrical microlens)
In the step of forming the photosensitive resin pattern that becomes the matrix of the semi-cylindrical microlens, a pattern consisting of the resin layer that becomes the semi-cylindrical microlens and the transparent layer formed on the resin layer is formed. A photosensitive resin layer is formed on the substrate, and the photosensitive resin layer is patterned by a photolithography method. In this state, a pattern of the photosensitive resin layer having a substantially rectangular cross-sectional shape is formed (not shown).

Next, by heat-treating the patterned photosensitive resin layer, a resist pattern 11 made of a photosensitive resin layer having a cross-sectional shape equivalent to that of a semi-cylindrical microlens is obtained (FIG. 2 (A). ) (F). In this way, an etching mask pattern for forming a semi-cylindrical microlens, that is, a mother mold of a semi-cylindrical microlens is formed.

In the mother mold of the semi-cylindrical microlens formed in this way, the pitch of the mother mold of the semi-cylindrical microlens in the direction orthogonal to the extending direction of the mother mold of the semi-cylindrical microlens is 10 μm. Even if the thickness is up to 20 μm, the cross-sectional shape of the matrix of the microlens is not disturbed (dented). The dent is usually formed in the central part of the cross-sectional shape of the matrix of the microlens, but a pattern made of the transparent layer 7 is formed in that part, and corresponds to the thickness of the pattern made of the transparent layer 7. And it is getting thicker. Since the thickness of the pattern composed of the transparent layer 7 is adjusted to a thickness at which the cross-sectional shape of the microlens is not disturbed (dented), the cross-sectional shape of the master mold is not disturbed (dented). There is nothing to do. To do this, it consists of a transparent layer that is 30% to 50% of the width of the semi-cylindrical microlens and 50% to 70% of the height (or thickness) of the semi-cylindrical microlens. It is necessary to form a pattern.

(Step of removing the pattern consisting of the mother mold of the semi-cylindrical microlens and the transparent layer by dry etching and transferring the semi-cylindrical microlens to the lens resin layer 9)
In the step of removing the pattern consisting of the mother mold (resist pattern 11) of the semi-cylindrical microlens and the transparent layer 7 by dry etching and transferring the semi-cylindrical microlens to the lens resin layer 9, the semi-cylindrical micro Using the lens master as an etching mask, the lens resin layer 9 that is a semi-cylindrical microlens underneath is dry-etched.

The type of dry etching is not particularly limited as long as it can be dry-etched by gasifying the resin using a gas containing oxygen gas. For example, a device called a plasma asher or an ozone asher can be used. The electrode configuration of the device may be a parallel plate type device or a barrel type device.

By performing dry etching, the lens resin layer 9 that becomes a semi-cylindrical microlens underneath that is not covered by the etching mask is dry-etched and removed. At the same time, the etching mask is also removed. When the etching mask disappears by dry etching, the form of the etching mask is transferred to the lens resin layer 9 which is a semi-cylindrical microlens underneath, and a lens array 8 composed of the semi-cylindrical microlens 1 is formed. (See FIGS. 2 (A) and 2 (g)).

By the method for manufacturing a semi-cylindrical microlens described above, a semi-cylindrical shape in which the cross-sectional shape of the semi-cylindrical microlens is not disturbed (dented) at a position corresponding to a photoelectric conversion element such as a photodiode. It is possible to form a lens array consisting of microlenses of the above. Therefore, it is possible to obtain a solid-state image sensor equipped with a lens array made of a semi-cylindrical microlens in which the cross-sectional shape of the semi-cylindrical microlens is not disturbed (dented).

<Second embodiment>
Next, the second embodiment of the solid-state image pickup device of the present invention will be described with reference to FIG. 2B, focusing on the differences from the first embodiment.

In the method for manufacturing a semi-cylindrical microlens in the second embodiment, first, a semiconductor substrate in which the photodiode 4 is arranged in an XY matrix is prepared (see FIGS. 2B and 2A), and the semiconductor substrate is prepared. The color filter 3 is formed on the top by aligning with the photodiode (see FIGS. 2B and 2B). Next, the flattening layer 2 is formed on the color filter 3 (see FIGS. 2B and 2C). Up to this point, it is the same as the first embodiment.
Next, a step of forming a pattern made of a transparent layer (see FIGS. 2B and 2d) and a step of forming a photosensitive lens resin layer 9-1 to be a semi-cylindrical microlens (FIG. 2B). ) (E), a step of forming the patterned photosensitive lens resin layer 12 (see FIGS. 2B and 2F), and heating and melting to form a semi-cylindrical microlens 1. The step (see FIGS. 2B and 2g) is carried out.
That is, in the second embodiment, the semi-cylindrical microlens is not formed by dry etching, but the semi-cylindrical microlens is formed by heating and melting.

First, a pattern composed of a transparent layer 7 is formed on a substrate provided with a color filter 3 and a flattening layer 2 on a semiconductor substrate for a solid-state image sensor in which a plurality of photodiodes 4 are formed in an XY matrix shape (FIG. 2). (B) See (d)). The pattern composed of the transparent layer 7 is equivalent to the transparent layer 7 in the first embodiment.
Next, a photosensitive lens resin layer 9-1 made of a transparent resin that becomes a semi-cylindrical microlens 1 is formed (see FIGS. 2B and 2e). The forming method is not particularly limited. For example, a photosensitive resin coating liquid made of a transparent resin is applied onto a substrate on which a pattern made of a transparent layer 7 is formed by a spin coating method.

Next, the coated photosensitive lens resin layer 9-1 is dried using a clean oven or the like. By exposing and developing with a photomask provided with a desired pattern, it is possible to form a patterned photosensitive lens resin layer 12 aligned with the pattern composed of the transparent layer 7 (FIG. 2B). (F)). This alignment is defined as a center line extending in the longitudinal direction through the center of the width of the pattern composed of the transparent layer 7 and a center line extending in the longitudinal direction through the center of the width of the semi-cylindrical microlens 1. It means that the positions are overlapped in a plan view.

The shape of the patterned photosensitive lens resin layer 12 formed as described above is a rectangular parallelepiped having a substantially rectangular end portion. By heat-treating the patterned photosensitive lens resin layer 12 having such a form above the softening point of the transparent resin constituting the patterned photosensitive lens resin layer 12, the transparent resin is melted and made into a liquid to flow. Therefore, the transparent resin pattern that was a rectangular body can be made into a semi-cylindrical microlens 1 (see FIGS. 2B and 2g).

When the patterned photosensitive lens resin layer 12 is melted, there is a phenomenon that a recess is formed around the thickest portion in the cross-sectional shape of the semi-cylindrical microlens 1. This phenomenon is observed when the width of the semi-cylindrical microlens 1 is 10 μm or more and the thickness is 1.5 μm or more. It is presumed that this is a phenomenon based on the surface tension of the liquid transparent resin because the patterned photosensitive lens resin layer 12 becomes liquid. Therefore, if the width of the transparent resin pattern is less than 10 μm and the thickness is less than 1.5 μm, the recesses are not formed, but if the width is more than those values, there is a possibility that the recesses are formed.

In order to prevent the phenomenon that this recess is formed, in the present invention, in the cross-sectional shape of the semi-cylindrical microlens 1, the transparent layer 7 is placed under each semi-cylindrical microlens 1 centering on the thickest portion. Form a pattern consisting of. The pattern composed of the transparent layer 7 passes through the midpoint in the width direction of the semi-cylindrical microlens 1 and along the center line extending in the longitudinal direction, 30% to 50% of the semi-cylindrical microlens 1. It has a width of% and a height of 50% to 70%, and is formed at a position that passes through the midpoint in the width direction of the pattern made of the transparent layer 7 and overlaps with the center line extending in the longitudinal direction. The feature is the same as that of the first embodiment.

The lens array 8 is provided with a plurality of semi-cylindrical microlenses 1 parallel to each other at a constant pitch in a direction orthogonal to the extending direction of the semi-cylindrical microlens 1. ..

By forming such a lens array 8 on a semiconductor substrate for a solid-state image pickup device in which photoelectric conversion elements such as a photodiode are formed in an XY matrix, the solid-state image pickup device according to the second embodiment of the present invention is formed. You can get 20.

The refractive index of the pattern composed of the transparent layer 7 may be equal to or less than that of the semi-cylindrical microlens 1. In other words, the refractive index of the semi-cylindrical microlens 1 is preferably equal to or higher than the refractive index of the pattern composed of the transparent layer 7. If the refractive index satisfies this relationship, reflection at the interface between the pattern made of the transparent layer 7 and the semi-cylindrical microlens 1 can be suppressed, and the light collection efficiency can be further improved.

1 ... Semi-cylindrical microlens 2 ... Flattening layer 3 ... Color filter 4 ... Photodiode 5 ... Incident light 6 ... Lens disturbance 7 ... Transparent layer ( Pattern consisting of)
8 ... Lens array 9 ... Lens resin layer 9-1 ... Photosensitive lens resin layer 10, 10-1, 10', 20 ... Solid image sensor 11 ... Resist pattern 12 ... Patterned photosensitive lens resin layer

Claims (8)

A semiconductor substrate for a solid-state image sensor in which a plurality of photoelectric conversion elements are arranged in an XY matrix consisting of an X direction and a Y direction orthogonal to the X direction, and a plurality of semiconductor substrates arranged so as to overlap the photoelectric conversion elements in a plan view. A solid-state image sensor equipped with a lens array consisting of semi-cylindrical microlenses.
Each of the semi-cylindrical microlenses constituting the lens array is stretched along the X direction or the Y direction of the photoelectric conversion element formed in an XY matrix, and the longitudinal direction of the semi-cylindrical microlens. Are parallel to each other
A solid-state image sensor characterized in that the width of the semi-cylindrical microlens is 10 μm or more and 20 μm or less, and the height is 1.5 μm or more and 3.0 μm or less. It has a pattern consisting of a transparent layer covered with the semi-cylindrical microlens.
The width of the pattern made of the transparent layer is 30% or more and 50% or less of the semi-cylindrical microlens.
The solid-state image sensor according to claim 1, wherein the height of the pattern made of the transparent layer is 50% or more and 70% or less of the semi-cylindrical microlens. The feature is that the center line extending in the longitudinal direction through the center of the width of the pattern made of the transparent layer and the center line extending in the longitudinal direction through the center of the width of the semi-cylindrical microlens overlap in a plan view. The solid-state image pickup device according to claim 2. The solid-state image sensor according to claim 2 or 3, wherein the refractive index of the semi-cylindrical microlens is equal to or higher than the refractive index of the pattern made of the transparent layer. The method for manufacturing a solid-state image sensor according to claim 1.
The step of forming the resin layer to be the semi-cylindrical microlens, and
The process of forming a pattern consisting of a transparent layer and
The process of forming a photosensitive resin pattern that serves as a base for the semi-cylindrical microlens, and
The step of forming the matrix of the semi-cylindrical microlens by heat-treating the photosensitive resin pattern, and
It is provided with a step of removing the pattern consisting of the mother mold of the semi-cylindrical microlens and the transparent layer by dry etching and transferring the semi-cylindrical microlens to the resin layer to be the microlens. A method for manufacturing a solid-state image sensor as a feature. The feature is that the center line extending in the longitudinal direction through the center of the width of the pattern made of the transparent layer and the center line extending in the longitudinal direction through the center of the width of the semi-cylindrical microlens overlap in a plan view. The method for manufacturing a solid-state image sensor according to claim 5. The method for manufacturing a solid-state image sensor according to any one of claims 2 to 4.
The step of forming the resin layer to be the semi-cylindrical microlens, and
The process of forming a pattern consisting of a transparent layer and
The step of forming a photosensitive resin pattern to be a semi-cylindrical microlens, and
A method for manufacturing a solid-state image sensor, which comprises a step of forming the semi-cylindrical microlens by heat-treating the photosensitive resin pattern. The width of the pattern made of the transparent layer is 30% or more and 50% or less of the semi-cylindrical microlens.
The method for manufacturing a solid-state image sensor according to any one of claims 5 to 7, wherein the height of the pattern made of the transparent layer is 50% or more and 70% or less of the semi-cylindrical microlens. ..

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