JP2003229550A - Solid-state imaging device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that increase of converging efficiency is small since each microlens becomes an aspherical lens when increase of converging efficiency is attempted by increasing the size in a plan view of each of the microlenses, in a solid-state imaging device equipped with microlens array. <P>SOLUTION: First microlenses whose plane shape is circular or approximately circular are formed being isolated from each other, corresponding to the respective photoelectric conversion elements one by one which elements are selected in a diced pattern from a large number of photoelectric conversion elements. Patterns for microlenses wherein the respective patterns are overlapped partially with the adjacent first microlenses are formed, corresponding to photoelectric conversion elements one by one, to which elements the first microlenses do not correspond. The respective patterns are subjected to reflow and cooled, and a plurality of second microlenses are formed, thereby manufacturing microlens array. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image sensor, a method for manufacturing the same, and a method for manufacturing a microlens array.

[0002]

2. Description of the Related Art Today, in many image pickup devices such as video cameras and digital still cameras, CCD (charge coupled device) type solid-state image pickup devices and MOS (metal-oxide-semiconductor) type solid-state image pickup devices are used in areas. -Used as an image sensor.

In both CCD-type and MOS-type solid-state image pickup devices, a large number of photoelectric conversion elements are arranged in rows and columns in a matrix on one surface of a semiconductor substrate. When light enters these photoelectric conversion elements, charges are accumulated in the photoelectric conversion elements.

The solid-state image pickup element generates an output signal (pixel signal) based on the charges accumulated in each photoelectric conversion element. In many solid-state imaging devices, an output signal generation unit capable of generating an output signal based on the charges accumulated in each photoelectric conversion element is integrated on one semiconductor substrate together with the photoelectric conversion element.

The output signal generator can be roughly classified into two types depending on its configuration. One is a charge detection circuit that uses one or two types of charge transfer elements, which are CCDs, such as an output signal generator in a CCD solid-state image sensor, to detect the charge accumulated in a photoelectric conversion element. It is an output signal generation unit of a type that transfers to an output signal and generates an output signal here.

The CCD can be constructed by providing a channel on one surface of a semiconductor substrate and disposing a plurality of electrodes (transfer electrodes) on the channel via an electrically insulating film.

CCD used as an area image
Type solid-state image sensor usually has one photoelectric conversion element array
The first charge transfer elements (hereinafter,
It is called "vertical charge transfer device". ) And one second charge transfer element (hereinafter referred to as “horizontal charge transfer element”) electrically connected to these vertical charge transfer elements.

The other one is to connect a photoelectric conversion element and an output signal line via a transistor like an output signal generation section in a MOS type solid-state image pickup element, and to charge an electric charge accumulated in the photoelectric conversion element. It is an output signal generation unit of a type that detects a voltage signal or a current signal generated on the output signal line in response to generate an output signal. The transistor is used as a switching element for electrically connecting the photoelectric conversion element and the signal line at a desired time.

In a solid-state image pickup device used as an area image, in many cases, a microlens array is used to increase the amount of light incident on each photoelectric conversion device. This microlens array is composed of a large number of microlenses arranged one above each photoelectric conversion element.

In the microlens array, for example, a transparent resin layer formed of photoresist or the like is partitioned into a predetermined shape by a photolithography method or the like, and then the transparent resin layer of each partition is reflowed, and the corners of each partition are subjected to surface tension. It is obtained by rolling after rolling (hereinafter,
This method is called "first method". ). In the first method, one section is molded into one microlens.

Alternatively, after the first microlens array is formed on the layer formed of the desired microlens material by the above-mentioned first method, the three-dimensional shape of the first microlens array is etched to form the three-dimensional shape thereunder. It can also be manufactured by transferring to a lens material layer (hereinafter, this method is referred to as a "second method").

[0012]

In order to increase the amount of light incident on each photoelectric conversion element, it is desirable to collect as much light as possible with a microlens corresponding to the photoelectric conversion element. It is desirable to increase the size of each microlens in plan view as much as possible.

However, in the first method described above,
An ineffective area that cannot be a micro lens always occurs between the sections. In order to reduce the above-mentioned ineffective area, it is more advantageous to make each section into a square shape than to make it into a circular shape, but the microlens obtained by reflowing the square section becomes an aspherical lens. . If the microlens is an aspherical lens, since the aberration is large, the light-collecting efficiency of the corresponding photoelectric conversion element decreases.

According to the above-mentioned second method, by selecting the etching conditions for transferring the three-dimensional shape of the first microlens array to the microlens material layer,
It is possible to obtain a microlens array with a small ineffective area. However, if the individual microlenses forming the first microlens array are aspherical lenses, the microlenses obtained by transferring the three-dimensional shape will also be aspherical lenses.

An object of the present invention is to provide a solid-state image pickup device which can easily improve the light collection efficiency on the photoelectric conversion element. Another object of the present invention is to provide a method for manufacturing a solid-state image pickup device, in which the efficiency of collecting light on a photoelectric conversion element is easily improved.

Still another object of the present invention is to obtain a microlens array in which each microlens has a shape that can be regarded as a spherical lens or a substantially spherical lens and has a small ineffective area between these microlenses. To provide a method of manufacturing a microlens array that is easy to manufacture.

[0017]

According to one aspect of the present invention, there are provided (i) a semiconductor substrate, and (ii) a plurality of rows arranged in a matrix over a plurality of rows and a plurality of columns on one surface of the semiconductor substrate. Photoelectric conversion elements, (iii) an output signal generation unit capable of generating an output signal based on the charges accumulated in each of the photoelectric conversion elements, and (iv) one for each photoelectric conversion element The photoelectric conversion elements are arranged in a matrix above each of the plurality of photoelectric conversion elements corresponding to each other, and a space is formed between adjacent ones in a direction oblique to the row direction, while adjacent ones in the row direction are formed. A number of microlenses that are in line contact with each other in the column direction and are in line contact with each other in the column direction when viewed in plan view are thicker than the thickness at the location where the central portion of the line contact faces the void. A solid-state imaging device having a microlens array having the same is provided.

According to another aspect of the present invention, (A) a large number of photoelectric conversion elements are arranged in a matrix over a plurality of rows and a plurality of columns on one surface, and the plurality of photoelectric conversion elements are An output signal generation unit capable of generating an output signal based on the charges accumulated in each is formed, and further, a light shielding film that covers the output signal generation unit, and the light shielding film that covers the light shielding film in a plan view. A step of preparing a semiconductor substrate having at least a flattening film for providing a flat surface on which a microlens array is formed above a large number of photoelectric conversion elements; Forming a plurality of first microlenses corresponding to the photoelectric conversion elements selected in a checkerboard pattern from 1 to 1, each having a planar shape of a circle or an approximate circle, on the flattening film. And (C)
A plurality of microlens patterns are formed on the flattening film, one for each photoelectric conversion element not selected in the step (B) and partially overlapping with each neighboring first microlens. And a step (D) of reflowing each of the microlens patterns and then cooling the microlens patterns to form a plurality of second microlenses.

According to still another aspect of the present invention, (A) a large number of photoelectric conversion elements are arranged in a matrix over a plurality of rows and a plurality of columns on one surface, and the plurality of photoelectric conversion elements are provided. An output signal generation unit capable of generating an output signal based on the electric charge accumulated in each of the above, and a light shielding film that covers the output signal generation unit and a light shielding film that covers the light shielding film in plan view. A step of preparing a semiconductor substrate provided with at least a flattening film providing a flat surface on which a microlens array is formed above the plurality of photoelectric conversion elements;
(B) a step of forming a microlens material layer on the flattening film, and (C) one photoelectric conversion element selected from the large number of photoelectric conversion elements in a checkered pattern. A step of forming a plurality of first microlenses having a plane shape of a circle or an approximate circle on the microlens material layer so as to be separated from each other; and (D) each photoelectric conversion not selected in the step (C). Forming a plurality of microlens patterns on the microlens material layer, which correspond to the elements one by one, and partially overlap each neighboring first microlens; and (E) the microlens pattern. (F) each of the first microlenses, each of the second microlenses, and each of the microlenses; By etching the material layer, the manufacturing method of the solid-state imaging device including a step of transferring the first microlens and the second microlens each three-dimensional shape to the microlens material layer.

According to still another aspect of the present invention, there is provided a method of manufacturing a microlens array comprising a plurality of microlenses arranged in a matrix in a plurality of rows and a plurality of columns on one plane. (A) a step of forming a plurality of first microlenses, each of which has a circular shape or an approximate circle, in a checkered pattern on the one plane,
(B) Each covers the one plane exposed between the first microlenses adjacent in the row direction or the one plane exposed between the first microlenses adjacent in the column direction, and each of the neighboring first microlenses Forming a plurality of microlens patterns that partially overlap the lenses; and (C) forming a plurality of second microlenses by reflowing each of the microlens patterns and then cooling. A method of manufacturing a microlens array including the same is provided.

According to still another aspect of the present invention, there is provided a method of manufacturing a microlens array composed of a large number of microlenses arranged in a matrix in a plurality of rows and a plurality of columns on one plane. , (A) a step of forming a microlens material layer having a flat upper surface, and (B) a plurality of first microlenses each having a planar shape of a circle or an approximate circle are mutually formed on the microlens material layer. A step of forming a checkered pattern with a space therebetween, and (C) each of which includes the upper surface of the microlens material layer exposed between the first microlenses adjacent in the row direction or the first microlenses adjacent in the column direction. Forming a plurality of microlens patterns that cover the exposed upper surface of the microlens material layer and partially overlap with the respective first microlenses in the vicinity; (B) Reflowing each of the lens patterns and then cooling to form a plurality of second microlenses; and (E) each of the first microlenses, each of the second microlenses, and the microlens material. Etching the layer to transfer the three-dimensional shape of each of the first microlens and the second microlens to the microlens material layer.

When the microlens array is manufactured, if the first microlens and the second microlens are separately formed as described above, a microlens array including a large number of rectangular microlenses can be obtained.

In this microlens array, it is easy to make any of the microlenses, including the rectangular microlenses, spherical lenses or close to spherical lenses. It is also easy to narrow the ineffective area that does not function as a microlens.

By forming the microlens array of the solid-state image pickup device by the above-mentioned method, it becomes easy to improve the light collection efficiency on the photoelectric conversion device.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows steps in a method of manufacturing a microlens array according to a first embodiment.
Drawings (A1), (B1), (C1), and (D1) in FIG. 1 schematically show a pattern or a planar arrangement of microlenses formed in each step, and a drawing (A2),
(B2), (C2), and (D2) schematically show the cross-sectional shape of the pattern or microlens formed in each step.

As shown in FIGS. 1A1 and 1A2, when forming a microlens array,
First, a plurality of first microlens patterns 5A each having a planar shape of a circle or a polygon of an octagon or more are formed in a checkered pattern on a base layer 1 on which a microlens array is to be arranged. To do. Each illustrated first microlens pattern 5A has a disc shape.

These first microlens patterns 5
A is, for example, a transparent resin layer which is the base of these, and the underlayer 1
It can be manufactured by forming the transparent resin layer on the upper surface and then patterning the transparent resin layer into a predetermined shape by a photolithography method or the like. At this time, the upper surface of the underlayer 1 is preferably a flat surface.

The above-mentioned transparent resin layer can be reflowed, and is preferably formed of a transparent resin which, when cured after reflow, does not reflow even if heated again. Specific examples of such a transparent resin include acrylic photoresists such as MFR-345 and MFR-344 manufactured by JSR, and novolac photoresists.

In order to manufacture a microlens array having a small number of invalid regions, the first microlens patterns 5A are formed so that the first microlens patterns 5A are separated from each other in plan view. It is preferable to make the width as wide as possible within the range.

As shown in FIGS. 1 (B1) and 1 (B2), each first microlens pattern 5A is reflowed, rolled up by surface tension, and then cooled. From each individual first microlens pattern 5A, one microlens (hereinafter referred to as “first microlens”) 5 is formed.
You get one by one.

When the planar shape of the first microlens pattern 5A is circular, the first microlens 5 having a circular planar shape is obtained. When the plane shape of the first microlens pattern 5A is a polygon of octagon or more, the first microlens 5 having a plane shape of an approximate circle is obtained. Here, the “approximate circle” in the present specification means a shape in which the corners of an octagon or more polygon are rounded.

In any case, each first microlens 5 has a spherical lens shape or a surface shape that can be regarded as a substantially spherical lens. As shown in FIGS. 1C1 and 1C2, the second microlens pattern is provided between the first microlenses 5 adjacent in the row direction Dr and between the first microlenses 5 adjacent in the column direction Dc. Form 10A. In FIG. 1 (C1), each second
In order to make the microlens pattern 10A easy to see, each second microlens pattern 10A is hatched.

As shown in the figure, each of the second microlens patterns 10A covers the surface of the underlying layer 1 exposed between the first microlenses 5 adjacent to each other in the row direction Dr or the column direction Dc, and each of the adjacent first microlenses 5A. It is formed so as to partially overlap with one microlens 5.

These second microlens patterns 1
The 0A can be formed by forming a transparent resin layer as a base thereof by a spin coating method or the like and then patterning the transparent resin layer into a predetermined shape by, for example, photolithography.

The transparent resin layer serving as the base of the second microlens pattern 10A is preferably formed of a light transmissive material whose refractive index after reflow, which will be described later, becomes the same as that of the first microlens 5. By forming the second microlens pattern 10A using a transparent resin of the same quality as the transparent resin used as the material of the first microlenses 5, a microlens array having no optical interface between adjacent microlenses is obtained. It will be easier.

In FIG. 1 (C1), each second microlens pattern 10A is in point contact with a neighboring second microlens pattern 10A in plan view, but these second microlens patterns 10A are in contact with each other. Are preferably separated from each other.

In order to manufacture a microlens array having a small number of ineffective areas, the plane shape of each second microlens pattern 10A is rectangular or square, and
The size of each of the second microlens patterns 10A in plan view is set to be the size of each of the neighboring second microlens patterns 1
It is preferable to make it as large as possible within a range where it does not come into contact with 0a.

At this time, in order to form the second microlens pattern 10A into a microlens having a spherical lens shape or a surface shape that can be regarded as a substantially spherical lens, the individual second microlens patterns 10 are formed.
It is preferable to select the sizes of the second microlens pattern 10A and the first microlenses 5 so that A and the respective first microlenses 5 in the vicinity thereof are overlapped as follows. That is, when an area where each of the second microlens patterns 10A and the first microlenses 5 in the vicinity thereof overlap is viewed in a plan view, approximately 50% or more of one side of the second microlens pattern 10A, preferably It is preferable to select the size of each of the second microlens pattern 10A and the first microlens 5 so that 60% or more of the area is located on the first microlens 5.

After this, FIG. 1 (D1) and FIG. 1 (D2)
As shown in, each second microlens pattern 10A
Are reflowed, rolled up by surface tension and then cooled. One microlens (hereinafter referred to as “second microlens”) 10 is obtained from each second microlens pattern 10A, and a microlens array 20 is obtained.

As shown in FIG. 1D2, when the refractive index of the first microlens 5 and the refractive index of the second microlens 10 are the same, no optical interface is formed between these microlenses. . Individual second microlens 10
Will be formed from the second microlens pattern 10A and one region of the first microlens 5 located thereunder. Therefore, each microlens 5,
The thickness of the central portion of the contact portion 10 with the adjacent microlens is larger than the thickness of the portion facing the ineffective region that does not function as the microlens.

Here, the second microlens pattern 10A formed by the above-described method has a spherical lens shape, or a second surface having a surface shape that can be regarded as a substantially spherical lens.
The reason why the microlens 10 is obtained will be described with reference to FIG.

FIG. 2 shows a state where the second microlens pattern 10A formed so as to partially overlap with each of the four first microlenses 5 is reflowed. In the figure, the reflowed second microlens pattern is indicated by reference numeral 10B.

The planar shape of the second microlens pattern 10A before reflow is a rectangle or a square, as described above. When a pattern with a rectangular shape or a square shape is formed on a flat surface and then reflowed, the shape becomes a shape with the four corners of the rectangle or square rounded, and the curvature of the surface becomes smaller toward the center in plan view. Become. It becomes an aspherical lens shape. The reason for this is presumed that when reflowing, the force that tends to become a hemisphere due to surface tension acts, but also the force that attempts to follow the shape (rectangular or square) of the contact surface between the flat surface and the pattern. It

However, the second microlens pattern 10A is formed so as to partially overlap the first microlenses 5A. The surface shape of the reflowed second microlens pattern 10B is a spherical lens shape,
Alternatively, it is stable in a shape that can be regarded as a substantially spherical lens. The reason for this is that, in addition to the surface tension, a force that attempts to follow the surface shape (spherical lens shape, or a shape that can be regarded as a substantially spherical lens) of each first microlens 5A located thereunder acts. It is presumed to be because of this.

Therefore, if the reflowed second microlens pattern 10A is cooled, the spherical lens shape,
Alternatively, the second microlens 10 having a surface shape that can be regarded as a substantially spherical lens is obtained.

FIGS. 3 and 4 are scanning electron micrographs showing the shapes of the microlens arrays manufactured according to the above-described method when they are perspectively viewed from different directions, and FIG. 5 is shown in FIGS. It is a scanning electron micrograph which shows the planar shape of the shown micro lens array. The photographing magnification of each photograph is 7500 times.

As is clear from FIGS. 3 and 4, according to the above method, it is possible to manufacture a microlens array in which each microlens has a spherical lens shape or a surface shape that can be regarded as a substantially spherical lens. it can.

As shown in FIG. 5 and as shown in FIG. 1 (D1), in the microlens array manufactured according to the above-described method, the microlenses in the outermost rows and columns are excluded. The planar shape of each microlens is a shape in which the four corners of a quadrangle are rounded. Hereinafter, these microlenses are referred to as “rectangular microlenses”.

In these rectangular microlenses, those adjacent to each other in the row direction and those adjacent to each other in the column direction are in line contact with each other on one side of a quadrangle with the four corners rounded in plan view. The outermost microlenses in each row and each column are also in line contact with each other in a row direction and in a row direction, and are adjacent to each other in a column direction.

A void (ineffective region) is formed between the microlenses adjacent to each other in the direction oblique to the row direction. By forming adjacent microlenses in contact with each other as described above, it is possible to easily obtain a microlens array in which each microlens has a large area in plan view and a narrow invalid region that does not function as a microlens. it can. Such a microlens array cannot be obtained by the first method and the second method described above.

Next, a method of manufacturing the microlens array according to the second embodiment will be described with reference to FIGS. 6 and 7. As shown in FIG. 6, in manufacturing the microlens array by the method of the present embodiment, first, the underlayer 1 on which the microlens array is to be arranged.
A microlens material layer 25A is formed on top of it,
The microlens array 20 is formed according to the manufacturing method according to the first embodiment described above.

The microlens material layer 25A can be formed using various materials such as an organic or inorganic material which has a desired refractive index and is transparent in the visible light region, for example, transparent resin, silicon oxide, silicon nitride and the like. is there. The macrolens material layer 25A has a thickness capable of transferring the three-dimensional shape of the microlens array 20 and a flat upper surface.

Thereafter, the microphone lens array 20 and the microlens material layer 25A are removed by a method such as reactive ion etching until the microlens array 20 disappears, that is, each of the first microlenses 5 and the second microlenses 10. Etch anisotropically until each disappears. The etching conditions at this time are appropriately selected according to the material of the microlens array 20 and the material of the microlens material layer 25A.

As shown in FIG. 7, the three-dimensional shape of the microlens array 20 is transferred to the microlens material layer 25A by the above etching, and the microlens array 25 is obtained. In the figure, reference numeral 2 denotes a microlens to which the three-dimensional shape of the first microlens 5 is transferred.
The reference numeral 23 denotes the microlens shown by 1 and having the three-dimensional shape of the second microlens 10 transferred thereto.

According to this method, the range of selection of the microlens material, in other words, the range of selection of the refractive index of the microlens is widened as compared with the manufacturing method according to the first embodiment.
In the above method, instead of the microlens array 20,
A three-dimensional shape is the same as that of the microlens array 20, but it is also possible to use a member formed of a material having no or low light transmittance.

Next, the solid-state image sensor according to the embodiment will be described with reference to FIGS. FIG. 8 shows a photoelectric conversion element 110 in the solid-state image sensor 100 according to the embodiment.
The planar arrangement of the first charge transfer element (vertical charge transfer element) 120, the second charge transfer element (horizontal charge transfer element) 140, and the charge detection circuit 150 is schematically shown.

The solid-state image sensor 100 shown in the figure is a solid-state image sensor used as an area image sensor, and a large number of photoelectric conversion elements 110 are arranged in a square matrix in a plurality of rows and a plurality of columns on one surface of the semiconductor substrate 1. (Including the case where the number of rows and the number of columns are different). The total number of photoelectric conversion elements 110 in an actual solid-state image sensor used as an area image sensor is, for example, several hundred thousand to several million.

Each of the photoelectric conversion elements 110 is formed of, for example, an embedded pn photodiode, and has, for example, a rectangular shape in plan view. When light enters the photoelectric conversion element 110, charges are accumulated in the photoelectric conversion element 110.

In order to transfer the charges accumulated in each photoelectric conversion element 110 to the charge detection circuit 150, one vertical photoelectric transfer element array is provided for each photoelectric conversion element array, and vertical charge transfer elements 120 are provided along the photoelectric conversion element array. Will be placed. Each vertical charge transfer element 120 is composed of, for example, a four-phase drive type CCD.

In order to control the reading of charges from the photoelectric conversion element 110, each vertical charge transfer element 120 has a read gate 130, one for each corresponding photoelectric conversion element 110. In FIG. 8, the read gate 1
In order to make the position of 30 easy to see, each read gate 1
30 is hatched.

When a read pulse (potential is, for example, about 15 V) is supplied to the read gate 130, charges are read from the photoelectric conversion element 110 corresponding to the read gate 130 to the vertical charge transfer element 120. Photoelectric conversion element 110
The charges are read from the vertical charge transfer element 120 to the photoelectric conversion element row unit.

Each vertical charge transfer element 120 is driven by a predetermined drive signal to generate a corresponding photoelectric conversion element 110.
The charges read from are transferred to the horizontal charge transfer element 140. The horizontal charge transfer element 140 is, for example, a two-phase drive type C
It is composed of a CD. This horizontal charge transfer device 140
Driven by a predetermined drive signal, the charges received from each vertical charge transfer element 120 are transferred to the charge detection circuit 150.
Transfer to.

The charge detection circuit 150 sequentially detects charges transferred from the horizontal charge transfer element 140 to generate and amplify a signal voltage, and sequentially generates pixel signals.
The charge detection circuit 150 includes, for example, an output gate electrically connected to an output end of the horizontal charge transfer element 140, and a floating diffusion region (hereinafter, referred to as “FD region” formed in the semiconductor substrate 1 adjacent to the output gate. And a floating diffusion amplifier (hereinafter, “FDA”) electrically connected to the FD region.
Is abbreviated. ) And.

The output gate controls charge transfer from the horizontal charge transfer element 140 to the FD region. The potential of the FD region changes according to the charge amount. The FDA amplifies the potential fluctuation in the FD area and generates a pixel signal. This pixel signal becomes an output signal from the solid-state image sensor 100.

A reset gate is arranged adjacent to the FD region, and a reset drain region is formed in the semiconductor substrate 1 adjacent to the reset gate. The FD region, the reset gate, and the reset drain region form a reset transistor.

The charge after being detected by the FDA, or the charge that does not need to be detected by the FDA is FD.
It is swept from the region to the reset drain region through the reset gate, and is absorbed by the power supply voltage, for example.

Solid-state image pickup device 100 having the above-mentioned structure
Then, each vertical charge transfer element 120, horizontal charge transfer element 1
An output signal generation unit is configured by 40 and the charge detection circuit 150.

The solid-state image pickup device 100 described above has the microlens array manufactured by the method according to the first embodiment described above. This microlens array is manufactured by the method according to the first or second embodiment described above.

The structure of the solid-state image pickup device 100 will be described below with reference to the reference numerals used in FIG. 1 or FIG. 8 as an example in the case of having the microlens array 20 manufactured according to the method according to the first embodiment. Will be described in more detail together with its manufacturing method.

FIG. 9 schematically shows the upper surface of the solid-state image sensor 100. As shown in the figure, the microlens array 2
0 is the uppermost layer in the solid-state image sensor 100. One first microlens 5 is arranged corresponding to each photoelectric conversion element 110 selected in a checkered pattern from the large number of photoelectric conversion elements 110 described above. The second microlens 10 is
The photoelectric conversion elements 110 which are not selected when forming the first microlenses 5 are arranged in a checkered pattern one by one. Each microlens 5 and 10 includes the corresponding photoelectric conversion element 110 in plan view.

FIG. 10 schematically shows a sectional structure of the solid-state image pickup device 100 taken along line XX shown in FIG. As shown in the figure, the semiconductor substrate 101 has, for example, an n-type silicon substrate 101a and a p ⁻ type impurity-added region 101b formed on one surface thereof. p ⁻ type impurity doped region 1
01b is obtained by ion-implanting p-type impurities into one surface of the n-type silicon substrate 101a and then performing heat treatment.
Alternatively, it is formed by epitaxially growing silicon containing p-type impurities on one surface of the n-type silicon substrate 101a.

[0072] In the following description, to distinguish the size of the impurity concentration between the impurity doped region having the same conductivity type, in order from those impurity concentration is relatively low, p ^-
A type impurity doped region, a p type impurity doped region, ap ⁺ type impurity doped region, or an n ⁻ type impurity doped region, an n type impurity doped region, and an n ⁺ type impurity doped region. Except when the p ⁻ type impurity added region 101b is formed by the epitaxial growth method, it is preferable to form all the impurity added regions by ion implantation and subsequent heat treatment.

In the photoelectric conversion element 110, for example, a predetermined portion of the p ⁻ type impurity added region 101b is converted into the n type impurity added region 110a, and the n type impurity added region 11 is further converted.
It is composed of a buried type photodiode formed by converting the surface layer portion of 0a into the p ⁺ type impurity added region 110b. The n-type impurity added region 110a is
It functions as a charge storage region.

[0074] one by one to the photoelectric conversion element array of one row correspondingly, p ^- n-type channel 12 to -type impurity doped region 101b
3 is formed. Each n-type channel 123 has a substantially uniform impurity concentration over its entire length and extends along the corresponding photoelectric conversion element array. These n-type channels 1
Each of 23 functions as a charge transfer channel in the vertical charge transfer element 120 (hereinafter, referred to as “vertical charge transfer channel”).

One p-type impurity doped region 130a is arranged along each right edge of each photoelectric conversion element 110 (n-type impurity doped region 110a) in FIG. 8 or FIG. The length of the p-type impurity added region 130a in the column direction is
It is, for example, about half the length of the corresponding photoelectric conversion element 110 in the column direction. Each p-type impurity added region 130a is used as the channel region 130a for the read gate 130.

If necessary, a p-type impurity doped region is also arranged below each vertical charge transfer channel 123. The channel stop region CS is the photoelectric conversion element 11 excluding the formation portion of the read gate channel region 130a.
0 and the periphery of the vertical charge transfer channel 123 in plan view, and the charge transfer channels forming the horizontal charge transfer element 140 (hereinafter, referred to as “horizontal charge transfer channel”).
Is formed on the periphery in plan view. The channel stop region CS is composed of, for example, a p ⁺ -type impurity added region.

When the horizontal charge transfer element 140 is composed of a two-phase drive type CCD, the horizontal charge transfer channel has, for example, an n-type impurity added region and an n ⁻ -type impurity added region from the downstream side to the upstream side. It can be configured by repeatedly arranging in this order toward. In this specification, from the photoelectric conversion element 110 to the charge detection circuit 15
The movement of the charges transferred to 0 is regarded as one flow, and the relative positions of the individual members and the like are specified by calling them "what upstream", "what downstream", etc., as necessary.

The first electrically insulating layer 105 is arranged on the semiconductor substrate 101. On each photoelectric conversion element 110,
A thermal oxide film, for example, is arranged as the first electrically insulating layer 105, and an ONO film, for example, is arranged as the first electrically insulating layer 105 on a region other than the region on the photoelectric conversion element 110. .

The ONO film has a film thickness of, for example, 20 to 20.
A silicon oxide film (thermal oxide film) having a thickness of about 70 nm, a silicon nitride film having a thickness of about 30 to 80 nm, and a thickness of 10 to 10
A silicon oxide film having a thickness of about 50 nm is formed on the semiconductor substrate 101.
It is composed of a laminated film deposited in this order on top.
In FIG. 10, for convenience, one layer represents the first electrically insulating layer 105.

On the first electrically insulating layer 105, transfer electrodes (hereinafter, referred to as "vertical transfer electrodes") that constitute the vertical charge transfer element 120 and transfer electrodes (hereinafter, referred to as "vertical transfer electrode") that configure the horizontal charge transfer element 140. Horizontal transfer electrodes "), and various electrodes forming the charge detection circuit 150 are arranged. In FIG. 10, two regions in one vertical transfer electrode 125 are visible.

These electrodes use, for example, a first polysilicon layer and a second polysilicon layer which is formed after patterning the first polysilicon layer into a predetermined electrode and is then patterned into a predetermined electrode. Formed. Each electrode is covered with an electrically insulating film IF such as a thermal oxide film.

The second electrically insulating layer 160 includes photoelectric conversion elements 110, vertical transfer electrodes, and horizontal charge transfer element 14.
0 and the charge detection circuit 150 are covered so that the light shielding film 165, which will be described later, and the various electrodes thereunder are sufficiently electrically separated. The second electrically insulating layer 160 is, for example, silicon oxide by a physical vapor deposition method (hereinafter abbreviated as “PVD”) or a chemical vapor deposition method (hereinafter abbreviated as “CVD”). Is formed by depositing.

The light shielding film 165 covers each vertical transfer electrode, the horizontal charge transfer element 140, and the charge detection circuit 150 in plan view to prevent unnecessary photoelectric conversion from being performed in a region other than the photoelectric conversion element 110. To do. This light shielding film 165
Is formed by depositing a metal such as tungsten, aluminum, chromium, titanium, molybdenum, or an alloy of two or more of these metals by PVD or CVD.

The light shielding film 165 has one opening 165 a above each photoelectric conversion element 10 so that light can be incident on each photoelectric conversion element 110. The area of the individual openings 165a in plan view is equal to the area of the openings 16a.
5a corresponds to, for example, about 20% of the area of the photoelectric conversion element 110 in plan view or smaller. A region of the surface of the photoelectric conversion element 110, which is located in the opening 165a in plan view, is a light incident surface of the photoelectric conversion element 110.

A wiring (not shown) to which a drive signal for the vertical charge transfer element 120 is supplied and the horizontal charge transfer element 140.
When a wiring (not shown) to which a drive signal for driving is supplied is formed of a material different from the material of the light shielding film 165, as shown in FIG. 10, an interlayer insulating film is formed on the light shielding film 165. It is preferable to form 170.

The interlayer insulating film 170 is formed by depositing silicon oxide or the like by PVD or CVD, for example, to prevent short circuit between each vertical transfer electrode and wiring and short circuit between the horizontal transfer electrode and the wiring. To do. When the wiring is formed of the same material as the material of the light shielding film 165, instead of omitting the interlayer insulating film 170, the second electrically insulating layer 160 is made thicker and the second electrically insulating film is formed. It is also possible to use the layer as an interlayer insulating film.

The passivation film 175 is the interlayer insulating film 1.
It is formed on 70 and protects the members below it. This passivation film 175 is formed by PVD or CVD, for example.
Is formed by depositing silicon nitride or the like.

The first planarization film 180 is formed of a passivation film 175 made of an organic material such as photoresist.
Formed on top to provide a flat surface for forming the color filter array 185. The first flattening film 180 is formed by, for example, a spin coat method.

The color filter array 185 is mainly arranged in a solid-state image pickup element used in a single-plate type image pickup device for color image pickup. The color filter array can be omitted in a solid-state image pickup device for monochrome photography and a solid-state image pickup device used in a three-plate image pickup device.

This color filter array 185 is, for example,
It can be produced by sequentially forming layers of three or four types of resins (color resins) colored in mutually different colors at predetermined locations by a method such as photolithography. In a solid-state image pickup device used in a single-plate type image pickup device for color photography, a primary color system or a complementary color system color filter array is arranged. FIG. 10 shows two red filters 185R and one green filter 185G.

A second planarization film 190 is formed on the color filter array 185 to provide a flat surface 190a for forming the microlens array 20. The second flattening film 190 is formed of an organic material such as photoresist, similar to the first flattening film 180.

Since the microlens array 20 has already been described, its description is omitted here. Instead of the microlens array 20, the microlens array can be formed according to the method according to the second embodiment described above.

Solid-state image sensor 1 having the above-mentioned cross-sectional structure
Since 00 has the microlens array 20 already described, it is easy to improve the light collection efficiency to each photoelectric conversion element 110.

The light-collecting efficiencies of the first microlens 5 and the second microlens 10 are greatly influenced by the curvature of the surface if the materials of these microlenses are the same, and the curvature of the surface is different from that of the microlenses 5. It greatly depends on the thickness (height) of 10 and the size in plan view. The thickness (height) of each of the microlenses 5 and 10 is controlled, in other words, the material of the transparent resin (clay) used as the material of the microlenses, and the transparency formed into the microlenses by reflow and subsequent cooling. A light-collecting efficiency of the first microlens 5 and a light-collecting efficiency of the second microlens 10 are relatively changed by appropriately selecting the film thickness of the resin pattern, the size in plan view, the reflow condition, and the like. You can

For example, when the array of each color filter in the primary color filter array 185 is Bayer array, the green filters 185G are distributed in a checkered pattern. Green filter 1
The light collection efficiency of the microlens corresponding to 85G (the first microlens 5 in the solid-state imaging device 100 shown in FIG. 10), the red filter 185R, and the blue filter (FIG. 10).
Is not visible in. It is possible to control the sensitivity characteristic of the solid-state imaging device 100 by making the light collection efficiency of the microlens (the second microlens 10 in the solid-state imaging device 100 shown in FIG. 10) corresponding to (4) different from each other. .

Although the method of manufacturing the microlens array, the solid-state image pickup device and the method of manufacturing the same according to the embodiments have been described above, the present invention is not limited to the above-described embodiments.

In particular, the configuration of the solid-state image sensor other than the microlens array can be variously changed according to the intended use and performance of the solid-state image sensor. For example, when a large number of photoelectric conversion elements are arranged in a square matrix, the configuration of the vertical charge transfer elements may be a configuration including, for example, two to three vertical transfer electrodes per photoelectric conversion element row. it can.

In FIG. 11, a large number of photoelectric conversion elements 110 are arranged in a square matrix, and each vertical charge transfer element 120 is one.
Two vertical transfer electrodes 125 per row photoelectric conversion element row
1 schematically shows a solid-state image sensor 100A including a and 125b.

Each of the vertical charge transfer devices 120 shown in the figure is a four-phase drive type C driven by four-phase drive signals φV1 to φV4 supplied via wirings WL _{V1 to} WL _V4.
Each of the vertical charge transfer channels 123 is formed of a CD and linearly extends along the corresponding photoelectric conversion element array.

The first vertical transfer electrodes 125a are arranged one by one on the upstream side of each photoelectric conversion element row so as to cross these vertical charge transfer channels 123 in plan view, and on the downstream side of each photoelectric conversion element row. The second vertical transfer electrodes 125b are arranged one by one. These first and second vertical transfer electrodes 1
25a to 125b extend along the corresponding photoelectric conversion element row, and on each vertical charge transfer channel 123,
One end of the vertical transfer electrode 125b is the first vertical transfer electrode 125.
It overlaps with one end of a in plan view.

If necessary, a plurality of vertical transfer electrodes, for example, three vertical transfer electrodes are further arranged on the downstream side of the most downstream second vertical transfer electrode 125b. Each of the vertical transfer electrodes constitutes a part of all the vertical charge transfer elements 120.

Although not shown in FIG. 11,
The solid-state image sensor 100A is the solid-state image sensor 1 described above.
00, the second electrically insulating layer 16 shown in FIG.
0, a light shielding film 165, an interlayer insulating film 170, a passivation film 175, a first flattening film 180, a color filter array 185, a second flattening film 190, and further on the second flattening film 190. Has a microlens array. The microlens array is manufactured according to the method according to the first or second embodiment described above.

A large number of photoelectric conversion elements forming the solid-state image pickup element can be arranged in a pixel shift manner. In this case, the configuration of the vertical charge transfer element can be configured to include, for example, one to two vertical transfer electrodes for each photoelectric conversion element row.

Here, the "pixel shift arrangement" in the present specification means that each photoelectric conversion element in an even-numbered photoelectric conversion element row is different from each photoelectric conversion element in an odd-numbered photoelectric conversion element row. , About 1/2 of the pitch of the photoelectric conversion elements in the photoelectric conversion element row, and the photoelectric conversion elements in the photoelectric conversion element rows that are even numbered are shifted from the photoelectric conversion element rows that are odd-numbered and shift in the column direction. Each of the conversion elements
About 1 / pitch of the pitch of photoelectric conversion elements in the photoelectric conversion element row
2. Displacement in the row direction means arrangement of a large number of photoelectric conversion elements such that each photoelectric conversion element column includes only photoelectric conversion elements in odd rows or even rows. "Pixel shift arrangement" is
This is a form in which a large number of photoelectric conversion elements are arranged in a matrix over a plurality of rows and a plurality of columns.

The above-mentioned "about 1/2 of the pitch of the photoelectric conversion elements in the photoelectric conversion element array" includes, in addition to 1/2, manufacturing error, rounding error of pixel position caused by design or mask manufacturing, etc. Although it deviates from 1/2 due to the factor, the value includes a value that can be regarded as substantially equal to 1/2 in view of the performance of the obtained solid-state imaging device and the image quality of the image. The same applies to the above-mentioned "about 1/2 of the pitch of the photoelectric conversion elements in the photoelectric conversion element row".

FIG. 12 schematically shows an example of a solid-state image pickup device in which a large number of photoelectric conversion elements are arranged in a pixel shift manner. The solid-state image sensor 200 shown in FIG. 11 is different from that shown in FIG. 11 except that (i) a large number of photoelectric conversion elements 110 are arranged in a pixel shift manner and (ii) each vertical charge transfer element 120 has a meandering shape. It has the same configuration as the illustrated solid-state imaging device 100A. FIG. 11 shows all the constituents that are functionally common to the constituents shown in FIG. The constituent elements that are functionally common to the constituent elements shown in FIG. 11 are designated by the same reference numerals as those used in FIG. 11, and the description thereof will be omitted.

When a large number of photoelectric conversion elements 110 are arranged so as to be pixel-shifted, it is easy to increase the integration degree of the photoelectric conversion elements 110 by forming each of the vertical charge transfer elements 120 in a meandering shape as shown in FIG. Become. Each of the vertical charge transfer channels 123 meanders along the corresponding photoelectric conversion element row, and each of the first vertical transfer electrodes 125a and the second vertical transfer electrodes 125b meanders along the corresponding photoelectric conversion element row.

Even when a large number of photoelectric conversion elements 110 are arranged with the pixels shifted, the photoelectric conversion elements 110 are arranged above the semiconductor substrate 101 as shown in FIG.
The second electrically insulating layer 160 and the light shielding film 16 shown in FIG.
5, the interlayer insulating film 170, the passivation film 175, the first flattening film 180, the color filter array 185, and the second flattening film 190 are sequentially formed, and the first or second embodiment described above is formed thereon. The microlens array is arranged according to the method according to the example.

When the microlens array constituting the solid-state image pickup device 200 is manufactured according to the method according to the first embodiment described above, all the photoelectric conversion elements 110 in each photoelectric conversion element row selected every other row are first arranged. 1 micro lens 5
(See FIG. 1 (D1)) corresponds to, and the second microlenses 10 (see FIG. 1 (D1)) correspond to all photoelectric conversion elements 110 in each photoelectric conversion element row selected every other row. To do.

However, looking at the distribution of the first microlenses 5 and the second microlenses 10 in the direction oblique to the photoelectric conversion element array in plan view, these first microlenses 5 are shown.
The second microlenses 10 are distributed in a checkered pattern.

Whether the vertical charge transfer element or the horizontal charge transfer element is driven by which phase of the drive signal is determined whether the plurality of photoelectric conversion elements are arranged in a square matrix or the pixels are arranged in a staggered manner. Depending on the number of vertical transfer electrodes corresponding to the photoelectric conversion element row of the row, or the number of horizontal transfer electrodes corresponding to one vertical charge transfer element, or the driving method of the vertical charge transfer element or the horizontal charge transfer element, It can be selected as appropriate. The horizontal charge transfer element can be configured by disposing two or more horizontal transfer electrodes for each vertical charge transfer element.

The microlens array 20 described with reference to FIGS. 1 to 5 and the microlens array 25 described with reference to FIGS. 6 to 7 can also be applied to a MOS type solid-state image pickup device.

FIG. 13A schematically shows the arrangement of a photoelectric conversion element and an output signal generator in a MOS type solid-state image sensor used as an area image sensor. In the illustrated solid-state imaging device 300, a large number of photoelectric conversion elements 210 are arranged on one surface of the semiconductor substrate 201 in a plurality of rows and a plurality of columns.
Are arranged in a square matrix. One photoelectric conversion element 210
Switching circuits (not shown) are connected to each one.

One output signal line 230 is arranged in each photoelectric conversion element array along the photoelectric conversion element array, and a load transistor 240 is connected to each of these output signal lines 230. Each output signal line 230 is connected to the signal generator 250.

When light enters the photoelectric conversion element 210, charges are accumulated in the photoelectric conversion element 210. By appropriately controlling the operation of a switching circuit (not shown), an electric signal having a magnitude corresponding to the charges accumulated in the photoelectric conversion element 210 can be generated on the corresponding output signal line 230. This electric signal is detected by the signal generation unit 250, converted into a predetermined output signal (pixel signal), and output. This output is the solid-state image sensor 30.
The output is 0.

In order to control the operation of the switching circuits connected to the individual photoelectric conversion elements 210 in units of photoelectric conversion element rows, the row read scanning section 260 and the row reset scanning section 26.
And 5 are arranged on the semiconductor substrate 201.

The row read scanning unit 260 controls the operation of each switching circuit to control the electrical connection between the photoelectric conversion element 210 and the corresponding output signal line 230.
The row reset scanning unit 265 controls the operation of each switching circuit to control the sweeping operation of the charges accumulated in the photoelectric conversion element 210.

In order to transmit the signals necessary for these controls, row selection signal line 224 and reset signal line 227.
However, each one is arranged corresponding to one photoelectric conversion element row. Also, one photoelectric conversion element row or one
A power supply voltage supply line 225 is arranged corresponding to each of the photoelectric conversion element columns of the column. Each switching circuit can also be electrically connected to these signal lines and supply lines.

The control unit 270 is disposed on the semiconductor substrate 201 and controls the operations of the signal generation unit 250, the row read scanning unit 260, and the row reset scanning unit 265. FIG.
(B) shows an example of a switching circuit. The switching circuit 220 shown in FIG.
1, a row selection transistor 222, and a reset transistor 223. These transistors are, for example, MOS type transistors.

The output transistor 221 and the row selection transistor 222 are connected in series, the photoelectric conversion element 210 is connected to the gate of the output transistor 222, and the row selection signal line 224 is connected to the gate of the row selection transistor 222. . The remaining one end of the output transistor is connected to the power supply voltage supply line 225, and the remaining one end of the row selection transistor 222 is connected to the output signal line 230.

The reset transistor 223 is connected to the wiring 226 connecting the output transistor 222 and the photoelectric conversion element 210, and at the same time, the power supply voltage supply line 225.
The reset signal line 227 is connected to its gate.

Each switching circuit 220, each output signal line 230, each load transistor 240, the signal generator 25.
0, row read scanning section 260, and row reset scanning section 2
65 constitutes an output signal generation unit.

From the row read scanning unit 260 to the row selection signal line 2
When a read signal is supplied to 24, the row select signal line 2
The row selection transistor 222 connected to 24 is turned on. The output transistor 221 and the output signal line 230 corresponding thereto are electrically connected.

The value of the voltage applied to the gate of the output transistor 221 changes according to the charge accumulated in the photoelectric conversion element 110 connected to the output transistor 221. Therefore, the output transistor 221
The magnitude of the drain current flowing in the photoelectric conversion element 210
It changes according to the electric charge accumulated in. As a result, when the row selection transistor 222 is turned on, the photoelectric conversion element 2
An electric signal corresponding to the charges accumulated in 10 is generated on the output signal line 230.

When the reset signal is supplied from the row reset scanning section 265 to the reset signal line 227, the reset transistor 223 connected to this reset signal line 227 is turned on. This reset transistor 22
3 corresponds to the photoelectric conversion element 210 of the power supply voltage supply line 22.
5, the electric charge accumulated in the photoelectric conversion element 210 is discharged to the power supply voltage supply line 225.

Also in the MOS type solid state image pickup device 300, the second substrate shown in FIG. 10 is provided above the semiconductor substrate 201.
Electrical insulating layer 160, light shielding film 165, interlayer insulating film 1
70, passivation film 175, first planarization film 18
0, the color filter array 185, and the second planarization film 1
90 are sequentially formed, and the microlens array is arranged thereon according to the method according to the first or second embodiment described above.

However, the color filter array can be omitted in both the CCD type and the MOS type solid-state image pickup devices as described above. When the color filter array is omitted, it is possible to omit the second planarizing film together and arrange the microlens array on the first planarizing film.

The first planarizing film can be omitted by forming the interlayer insulating film having a flat upper surface. Such an interlayer insulating film is made of, for example, silicon oxide (including spin-on glass), borophosphosilicate glass (BPSG), phosphosilicate glass (PSG), borosilicate glass (BSG), etc. and has a relatively thick wall. It can be formed by reflowing the layer or by subjecting the layer to etch back or chemical mechanical drilling.

It will be apparent to those skilled in the art that various other modifications, improvements, combinations and the like are possible.

[0130]

As described above, according to the present invention,
Provided is a solid-state imaging device that easily improves the efficiency of collecting light on a photoelectric conversion element. It becomes easy to provide a solid-state image sensor with high sensitivity.

[Brief description of drawings]

FIG. 1 is a process drawing showing a method of manufacturing a microlens array according to a first embodiment.

FIG. 2 is a diagram showing a method of manufacturing a microlens array according to the first embodiment, in which the second microlenses have a spherical lens shape;
Alternatively, it is a perspective view for explaining the principle of a microlens having a surface shape that can be regarded as a substantially spherical lens.

FIG. 3 is a scanning electron micrograph showing a shape of a microlens array manufactured by the method according to the first embodiment when viewed in perspective.

FIG. 4 is a scanning electron micrograph showing the shape of the microlens array shown in FIG. 3 when viewed from a direction different from that in FIG.

5 is a scanning electron micrograph showing a planar shape of the microlens array shown in FIG.

FIG. 6 is a cross-sectional view showing a step in the method of manufacturing a microlens array according to the second embodiment.

FIG. 7 is a cross-sectional view schematically showing a microlens array manufactured by the method of manufacturing a microlens array according to the second embodiment.

FIG. 8 is a photoelectric conversion element in a solid-state image sensor according to an embodiment,
FIG. 3 is a schematic diagram showing a planar arrangement of a first charge transfer element (vertical charge transfer element), a second charge transfer element (horizontal charge transfer element), and a charge detection circuit.

FIG. 9 is a plan view schematically showing a solid-state image sensor according to an example.

10 is a schematic view showing a cross section of the solid-state imaging device taken along line XX shown in FIG.

FIG. 11 is a schematic diagram showing a solid-state imaging device in which a large number of photoelectric conversion elements are arranged in a square matrix, and each vertical charge transfer element includes two vertical transfer electrodes per photoelectric conversion element row. .

FIG. 12 is a plan view schematically showing an example of a solid-state image sensor in which a large number of photoelectric conversion elements are arranged in a pixel shift manner.

13A is a schematic diagram showing the arrangement of a photoelectric conversion element and an output signal generator in a MOS solid-state image sensor used as an area image sensor, and FIG.
3B is a circuit diagram illustrating an example of a switching circuit connected to the photoelectric conversion element illustrated in FIG.

[Explanation of symbols]

5A ... 1st microlens pattern, 5 ... 1st microlens, 10A ... 2nd microlens pattern, 10 ... 2nd microlens, 20, 25 ... Microlens array, 25A ... Microlens material layer,
100, 100A, 200, 300 ... Solid-state image sensor,
101, 201 ... Semiconductor substrate, 110, 210 ... Photoelectric conversion element, 120 ... First charge transfer element (vertical charge transfer element), 123 ... Vertical charge transfer channel, 125 ...
Vertical transfer electrode, 125a ... First vertical transfer electrode, 125
b ... 2nd vertical transfer electrode, 130 ... read-out gate, 1
40 ... Second charge transfer element (horizontal charge transfer element), 15
0 ... Charge detection circuit, 160 ... Second electrical insulating layer,
165 ... Light shielding film, 170 ... Interlayer insulating film, 175 ...
Passivation film, 180 ... First planarization film, 1
85 ... Color filter array, 190 ... Second flattening film.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4M118 AB01 BA13 BA14 CA02 CA32                       FA06 FA07 GC07 GD02 GD04                       GD07                 5C024 AX01 CY33 CY47 EX43 GY01                       GY31                 5F088 AA02 AB03 BA18 BB03 CB18                       EA04 EA08 HA05 JA12 JA13                       KA03

Claims (11)

[Claims] 1. A semiconductor substrate, a large number of photoelectric conversion elements arranged in a matrix in a plurality of rows and a plurality of columns on one surface of the semiconductor substrate, and a charge accumulated in each of the photoelectric conversion elements. An output signal generation unit capable of generating an output signal based on the photoelectric conversion elements; and a plurality of photoelectric conversion elements arranged in a matrix above the plurality of photoelectric conversion elements, one corresponding to each photoelectric conversion element. While forming a gap between the adjacent ones in the row direction, the adjacent ones in the row direction are in line contact with each other in the plan view, and the adjacent ones in the column direction are in line contact with each other in the plan view, and the line contact is made. A microlens array having a large number of microlenses, the thickness of which is greater in the central portion than in the portion facing the void. 2. The solid-state image sensor according to claim 1, wherein the microlens array is formed of an acrylic photoresist. 3. The solid-state image sensor according to claim 1, wherein the plurality of photoelectric conversion elements are arranged in a pixel shift manner. 4. A CCD type solid-state image pickup device.
~ The solid-state image sensor according to claim 3. 5. A MOS type solid-state image pickup device.
~ The solid-state image sensor according to claim 3. 6. (A) A large number of photoelectric conversion elements are arranged in a matrix over a plurality of rows and a plurality of columns on one surface, and based on the charges accumulated in each of the plurality of photoelectric conversion elements. An output signal generation unit capable of generating an output signal is formed, and further, a light shielding film covering the output signal generation unit and an upper part of the plurality of photoelectric conversion elements by covering the light shielding film in plan view. A step of preparing a semiconductor substrate provided with at least a flattening film for providing a flat surface on which a microlens array is formed, and (B) each photoelectric conversion element selected from the plurality of photoelectric conversion elements in a checkered pattern. A step of forming a plurality of first microlenses corresponding to the conversion elements one by one and each having a planar shape of a circle or an approximate circle on the flattening film so as to be separated from each other; and (C) the step (C). Each photoelectric conversion element not selected in B) Forming a plurality of microlens patterns on the flattening film, each of which corresponds to one child, and partially overlaps each neighboring first microlens; and (D) forming the microlens pattern. And a step of forming a plurality of second microlenses by reflowing each of them and then cooling the solid-state image pickup element. 7. The solid-state imaging device according to claim 6, wherein the size of each of the first microlenses in plan view is the maximum size that can be formed by separating the first microlenses from each other. Manufacturing method. 8. The method according to claim 6, wherein each of the first microlenses and each of the second microlenses are formed of the same acrylic photoresist.
A method for manufacturing the solid-state imaging device according to item 1. 9. (A) A large number of photoelectric conversion elements are arranged on one surface in a matrix form over a plurality of rows and a plurality of columns, and based on charges accumulated in each of the plurality of photoelectric conversion elements. An output signal generation unit capable of generating an output signal is formed, and further, a light shielding film covering the output signal generation unit and an upper part of the plurality of photoelectric conversion elements by covering the light shielding film in plan view. And (B) forming a microlens material layer on the flattening film, and (B) forming a microlens material layer on the flattening film. C) A plurality of first microlenses each corresponding to one photoelectric conversion element selected in a checkered pattern from the plurality of photoelectric conversion elements, each having a planar shape of a circle or an approximate circle, Separated from each other on the lens material layer A step of forming them separately, and (D)
On the microlens material layer, a plurality of microlens patterns are provided on the microlens material layer, which correspond to the photoelectric conversion elements not selected in the step (C) one by one and partially overlap with the neighboring first microlenses. And (E) reflowing each of the microlens patterns and then cooling to form a plurality of second microlenses,
(F) By etching the first microlenses, the second microlenses, and the microlens material layer, the three-dimensional shape of each of the first microlenses and the second microlenses is changed to the microlenses. A method for manufacturing a solid-state imaging device, comprising the step of transferring to a material layer. 10. A method of manufacturing a microlens array comprising a plurality of microlenses arranged in a matrix in a plurality of rows and a plurality of columns on one plane, comprising:
(A) a step of forming a plurality of first microlenses each having a circular or approximate circle shape in a checkered pattern on one plane in a checkered pattern, and (B) each adjoining in the row direction The one plane exposed between the matching first microlenses,
Or a step of forming a plurality of microlens patterns that cover the one plane exposed between the first microlenses adjacent to each other in the column direction and partially overlap with the respective first microlenses in the vicinity; Reflowing each of the microlens patterns and then cooling the microlens patterns to form a plurality of second microlenses. 11. A method of manufacturing a microlens array comprising a plurality of microlenses arranged in a matrix in a plurality of rows and a plurality of columns on one plane, the method comprising:
(A) forming a microlens material layer having a flat upper surface, and (B) separating a plurality of first microlenses each having a planar shape of a circle or an approximate circle on the microlens material layer. And (C) exposing on the upper surface of the microlens material layer exposed between the first microlenses adjacent in the row direction or between the first microlenses adjacent in the column direction. To cover the upper surface of the microlens material layer and
Forming a plurality of microlens patterns that partially overlap the microlenses; and (D) forming a plurality of second microlenses by reflowing each of the microlens patterns and then cooling. And (E) etching each of the first microlenses, each of the second microlenses, and the microlens material layer to form a three-dimensional shape of each of the first microlenses and the second microlenses. And a step of transferring to a lens material layer.