JP2012256782A - Color solid-state imaging element, and method for manufacturing color micro lens used for the same - Google Patents

Abstract

By using an improved color microlens, it is possible to optimize the color separation property and light condensing property of the lens itself, and to block light from surrounding pixels, so that the color reproducibility as a whole is good. To provide a color solid-state imaging device with a simple manufacturing process.
A solid state in which a plurality of microlenses 6 are provided corresponding to each photoelectric conversion element on a light receiving surface side surface 4 of a solid-state imaging element pixel portion in which a plurality of photoelectric conversion elements 3 are arranged in a plane on a semiconductor substrate 2. In the imaging device 1, the microlens is regularly connected with a color microlens made of one of a plurality of colored transparent resins having a predetermined spectral transmittance characteristic and a color microlens made of a colored transparent resin of another color. The adjacent color microlenses of different colors are separated by a light-blocking black matrix pattern 7 lower than the height of the color microlenses.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing a color microlens provided in a color solid-state imaging device.

  In recent years, imaging devices have been widely used with the expansion of the contents of image recording, communication, and broadcasting. Various types of image pickup devices have been proposed. An image pickup device incorporating a solid-state image pickup device that has been stably manufactured with a small size, light weight, and high performance can be used as a digital camera or digital video. It has become widespread.

  The solid-state imaging device has a plurality of photoelectric conversion elements that receive an optical image from a subject and convert incident light into an electrical signal. The types of photoelectric conversion elements are roughly classified into CCD (charge coupled device) type and CMOS (complementary metal oxide semiconductor) type. In addition, there are two types of photoelectric conversion elements: linear sensors (line sensors) in which photoelectric conversion elements are arranged in a row, and area sensors (surface sensors) in which photoelectric conversion elements are two-dimensionally arranged vertically and horizontally. It is divided roughly into. In any of the sensors, as the number of photoelectric conversion elements (number of pixels) increases, the captured image becomes more precise. In recent years, in particular, a method for manufacturing a solid-state imaging element having a large number of pixels at low cost has been studied.

  In addition, a color solid as a single-plate color sensor that can obtain color information of an object by providing various color filters that transmit light of a specific wavelength in the path of light incident on the photoelectric conversion element. Imaging devices are also widespread. The color solid-state imaging device can collect one color pixel corresponding to one photoelectric conversion device and collect color-separated image information. As the color of the color filter, three primary colors composed of three colors of red (R), green (G), and blue (B), cyan (C), magenta (M), and yellow (Y) are used. Complementary color systems are generally used, and in particular, the three primary color systems are often used.

  The color filter is mainly formed using a photolithography method. That is, after applying a photosensitive colored transparent resin of a predetermined color on a substrate, pattern exposure and development are performed on the photosensitive colored transparent resin through an exposure photomask having a predetermined pattern, and a predetermined transparent portion is colored transparent. A color filter made of resin is formed. In addition, as the application of the photosensitive colored transparent resin on the substrate, a spin coating method is often used. That is, after the photosensitive colored transparent resin is dropped on the substrate, the photosensitive colored transparent resin dropped is uniformly spread on the substrate by rotating the substrate.

  One of the important issues in performance required for a solid-state imaging device is to improve the sensitivity to incident light. In order to increase the amount of information of an image photographed with a miniaturized solid-state imaging device, it is necessary to miniaturize and highly integrate a photoelectric conversion device serving as a light receiving unit. However, when the photoelectric conversion element is miniaturized, the area of each photoelectric conversion element is reduced, and the area ratio that can be used as the light receiving unit is also reduced. And the effective sensitivity decreases.

As a means for preventing such a decrease in sensitivity of the miniaturized solid-state imaging device, in order to efficiently capture light into the light receiving portion of the photoelectric conversion device, the light incident from the object is condensed and photoelectrically A technique has been proposed in which a microlens that leads to a light receiving portion of a conversion element is formed on the photoelectric conversion element. By condensing the light with the microlens and guiding it to the light receiving portion of the photoelectric conversion element, the apparent aperture ratio of the light receiving portion can be increased, and the sensitivity of the solid-state imaging device can be improved. FIG. 3 shows a conventional color in which one colorless and transparent microlens is provided for each pixel on a color filter pixel made of a colored transparent resin pattern to collect light and separate the color-separated light to a light receiving portion of a photoelectric conversion element. It is a schematic cross section for demonstrating the structure of a solid-state image sensor.
A plurality of color solid-state imaging devices 1 are arranged on the light-receiving surface side surface 4 of a solid-state imaging device pixel portion in which a plurality of photoelectric conversion devices 3 regularly provided on a semiconductor substrate 2 are arranged in a plane via a transparent flattening layer 5. A plurality of colored transparent pixel patterns 8 for repeatedly arranging colors are provided in correspondence with the photoelectric conversion elements 3, and further, planarization on a plane in which the colored transparent pixel patterns 8 are arranged by the second transparent planarization layer 51 is performed. The microlens 60 is provided.

  In addition, by adopting a color microlens that has a condensing function of the microlens and also has a function as a color filter made of a colored transparent resin, two layers of the microlens and the color filter can be obtained in a simple manufacturing process. A color solid-state imaging device has also been proposed in which a single layer structure is used instead of the structure or the three-layer structure including the second transparent flattening layer 51 to reduce the layer thickness and improve the light collection rate (Patent Document). 1). FIG. 4 is a schematic cross-sectional view for explaining the structure of a color solid-state imaging device using such a color microlens. A plurality of photoelectric conversion elements 3 regularly provided on the semiconductor substrate 2 are arranged on a light-receiving surface side surface 4 of a solid-state image pickup element pixel portion, and each of the photoelectric conversion elements corresponds to each other through a transparent flattening layer 5. 1 shows a color solid-state imaging device 1 in which a plurality of different color microlenses 6 are regularly and repeatedly arranged at positions. The color microlens 6 generally has a difficulty in achieving both color separation properties and light condensing properties, and color separation is performed for light 9 that passes through a thin portion at the edge of the lens indicated by a broken line arrow in the figure. If the overall film thickness is increased and the color separation is improved, it becomes difficult to control the curvature and an appropriate light collecting property cannot be obtained.

On the other hand, when the number of pixels of the color solid-state imaging device increases and the pixel size becomes finer, the influence of a slight oblique incidence of incident light cannot be ignored, and photoelectric conversion corresponding to each color pixel pattern of the colored transparent layer The incident color enters other adjacent photoelectric conversion elements other than the elements, and color mixing occurs. As a result, the color reproducibility of the color solid-state imaging device is significantly deteriorated.
In order to prevent the above-mentioned color mixture and provide a color solid-state imaging device with good color reproducibility, a black matrix is provided between pixel patterns of each color of a color filter colored transparent layer in which a conventional colorless and transparent microlens is separately provided. It has been proposed to stably form a light shielding pattern made of (see Patent Document 2). However, the manufacturing process becomes longer because of the structure in which a two-layer structure of a microlens and a color filter or a three-layer structure including the second transparent planarization layer 51 is separately provided.

JP 2006-332407 A JP 2010-134352 A

  The present invention is proposed in view of the above-described problems, and the problem to be solved by the present invention is that the use of an improved color microlens makes it possible to obtain proper color separation and condensing performance of the lens itself. It is to provide a color solid-state imaging device having a good color reproducibility as a whole by a simple manufacturing process while blocking light from surrounding pixels.

As means for solving the above-described problems, the invention according to claim 1 is directed to each of the photoelectric conversion elements on the light receiving surface side surface of the solid-state imaging element pixel portion in which a plurality of photoelectric conversion elements are arranged in a plane on a semiconductor substrate. In the solid-state imaging device provided with a plurality of microlenses corresponding to the color microlens, the microlens is made of a colored transparent resin of one color out of a plurality of colors having a predetermined spectral transmittance characteristic. A color microlens made of resin is regularly and repeatedly arranged, and adjacent color microlenses of different colors are separated by a black matrix pattern having a light shielding property lower than the height of the color microlens. This is a color solid-state imaging device.

  The invention described in claim 2 is a method of manufacturing a color microlens in the color solid-state image pickup device according to claim 1, wherein a black matrix is formed around a position where pixels of each color are formed, and then alkali-soluble. A color microlens material containing a photosensitive resin is applied to the light-receiving surface of the solid-state image sensor to a thickness greater than the thickness of the black matrix, and a color microlens layer corresponding to a predetermined pixel area is selected by photolithography using exposure and development. The method of manufacturing a color microlens is characterized in that the curved surface shape of the color microlens is formed by heat treatment using the heat flow behavior of the resin in the pixels limited to the black matrix pattern.

  The invention according to claim 3 is the method for producing a color microlens according to claim 2, wherein the height of the black matrix pattern is 0.3 to 2 μm.

  According to a fourth aspect of the present invention, the aspect ratio of the height exceeding the black matrix of the color microlens and the planar size of the color microlens provided surrounded by the black matrix is 0.2-7. 4. The method for producing a color microlens according to claim 2, wherein the color microlens is produced.

  According to a fifth aspect of the present invention, there is provided a method of manufacturing a color microlens in the color solid-state image pickup device according to the first aspect, wherein after the black matrix is formed around the position of each color pixel, the color microlens is formed. A lens material is applied to the light-receiving surface side of the solid-state imaging device, dried, and then an etching resist material containing an alkali-soluble photosensitive resin is laminated and applied so as to be thicker than the thickness of the black matrix, corresponding to a predetermined pixel region. The resist pattern is selectively left on the upper layer of the color microlens layer by photolithography, and the desired curved surface shape is formed by heat treatment using the heat flow behavior of the etching resist pattern within the pixel limited to the black matrix pattern. After that, the desired curved surface shape is formed by the dry etching method to the lower color microlens It is transferred to a manufacturing method of a color microlens and forming a curved shape of the color microlens.

  The invention according to claim 6 is the method for producing a color microlens according to any one of claims 2 to 5, wherein a plurality of colors constituting the color microlens are three or more colors. .

  The present invention integrates the functions of the color filter and the microlens constituting the color solid-state imaging device into a thin color microlens, and can secure an appropriate curvature of the lens curved surface. A color solid with good color reproducibility because a light-shielding pattern is provided between pixels with different color microlenses to prevent interference and sufficient color separation is achieved by securing a colored film thickness within the pixel. The image sensor can be manufactured with high accuracy by a simple manufacturing process.

It is a schematic cross section for demonstrating the structure of the color solid-state image sensor of this invention. It is a schematic cross section for explaining an example of the manufacturing method of the color microlens of this invention in order of a process, (a) is a black matrix formation stage, (b1)-(b3) are the color microlens formation process of the 1st color. , (C1) to (c3) show the second color microlens formation step. It is a schematic cross section for demonstrating the structure of the color solid-state image sensor using the conventional microlens. It is a schematic cross section for demonstrating the structure of the color solid-state image sensor using the conventional color microlens. It is a schematic cross section for explaining other examples of the manufacturing method of the color microlens of this invention in order of a process, (a) is a black matrix formation stage, (b1)-(b4) are the color microlenses of the 1st color. The forming process, (c1) to (c4) show the second color microlens forming process. It is a schematic cross section for defining an aspect ratio representing the shape of the color microlens of the present invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view for explaining the structure of the color solid-state imaging device of the present invention.

The present invention corresponds to each of the photoelectric conversion elements 3 through the transparent flattening layer 5 on the light receiving surface side surface 4 of the solid-state imaging element pixel portion in which a plurality of photoelectric conversion elements 3 are arranged in a plane on the semiconductor substrate 2. The color solid-state imaging device 1 is provided with a plurality of color microlenses 6, and the color microlens 6 is made of a colored transparent resin of one of a plurality of colors having a predetermined spectral transmittance characteristic, and other colors The color microlens made of the colored transparent resin is regularly and repeatedly arranged, and between the adjacent color microlenses of different colors, the light-shielding black matrix 7 pattern is lower than the color microlens height. It is characterized by being separated.
In the present invention having the above-described features, the functions of the color filter and the microlens constituting the color solid-state imaging device are thinned and integrated into the color microlens, so that the entire manufacturing process is shortened and alignment between patterns is performed. The number of times is reduced, and a highly accurate product can be obtained. In addition, by providing a black matrix shading pattern partition between the color microlenses, the color reproducibility can be improved, and the control of the position and shape of the color microlens with respect to the black matrix is also described in the description of the manufacturing method described later. As stated, it is advantageous.

  FIGS. 2A and 2B are schematic cross-sectional views for explaining an example of the manufacturing method of the color microlens of the present invention in the order of steps, where FIG. 2A is a black matrix forming stage, and FIGS. 2B to 3B are the first color. Microlens formation process, (c1) to (c3) show the second color microlens formation process.

As shown in FIG. 2A, the black matrix 7 is formed of a light-shielding material around a position 60 that is a pixel of each color corresponding to the photoelectric conversion element 3 on a one-to-one basis. In advance, the transparent flattening layer 5 that provides a flat and uniform base is formed by, for example, applying a colorless and transparent acrylic resin solution with a thickness of about 0.1 μm and heat-treating it.
Next, the black matrix 7 is formed by performing a general photolithography process in which a light-shielding material imparting photosensitivity to a black material is applied, dried, selectively exposed, developed, and cured by heat treatment. As a result, the pattern can be directly formed.
Further, a method using a dry etching method advantageous for forming a fine pattern is also possible. That is, a pattern to be an etching resist is formed on the light-shielding material that does not require photosensitivity previously formed by a photolithography method similar to the above, and the pattern formation of the light-shielding material is formed by dry etching. be able to. The latter method is particularly suitable for the formation of a miniaturized pattern because the suitability for photolithography and the suitability for dry etching can be shared between the resist material and the light shielding material. In order to particularly reinforce the dry etching resistance, it is possible to form an inorganic film below the resist material and complete the dry etching of the light shielding material into a more favorable shape. It is also possible to form an inorganic film as a light-shielding material in a vacuum, and after forming an etching resist pattern on the upper layer, the lower inorganic light-shielding film can be patterned by dry etching or wet etching.

  As will be described later, the thickness of the black matrix 7 is at least 0.3 μm or more in order to obtain a sufficient color separation by securing the colored film thickness by blocking the color microlens in the pixel. It is desirable. On the other hand, if the thickness is too thick, defects are likely to occur during black matrix pattern formation, which is not preferable in terms of productivity in the manufacturing process and material utilization efficiency.

Next, the process for forming the first color microlens will be described.
As shown in FIG. 2 (b1), the color microlens material 61m is made thicker than the thickness of the black matrix 7 on the light-receiving surface side substrate of the solid-state imaging device pixel portion on which the black matrix prepared in FIG. 2 (a) is formed. Apply. The color microlens material includes a photosensitive material including a specific color pigment having a predetermined spectral transmittance characteristic and an alkali-soluble resin. For example, the resin in the light-irradiated region is decomposed to be alkali-soluble. An acrylic positive type photosensitive resin can be used. As the application of the photosensitive colored transparent resin on the substrate, a spin coating method can be used.

  The coated and dried color microlens material 61m is exposed and developed, and the color microlens layer 61p selected by the photolithography method is formed in a predetermined pixel region as shown in FIG. 2 (b2). Leave correspondingly. For the exposure process, a stepper capable of repeatedly projecting the enlarged pattern of the exposure mask by reducing projection exposure and repeatedly feeding it can be used. In this process, it is natural to use a precise alignment mechanism to control the position and shape of the color microlens with respect to the black matrix. However, the shape has been improved by devising the exposure mask described below. it can. Further, the behavior in the next heat flow step is also effective in controlling the position and shape of the color microlens in this example.

  By using a photomask called a gray mask having an intermediate density region to which transmittance gradation is given as an exposure mask, the cross-sectional shape of the color microlens layer 61p after development and before heat flow is more than illustrated. A gentle shape can be used to assist flow molding by heat treatment described below. The development step is performed using an alkaline developer, for example, an organic alkaline developer aqueous solution such as tetramethylammonium hydroxide (TMAH).

  The gray mask that can be used as the exposure mask can be a gray tone mask or a half tone mask. A gray tone mask is a type that forms a semi-transparent portion as an average of the entire fine pattern area by a collection of fine patterns of light shielding films such as dot (halftone dot) arrangement and line and space. The mask is a type in which a semi-transparent portion is formed by direct film formation of a semi-transmissive film and patterning means. The former gray-tone mask type, in which only one type of light-shielding film needs to be vacuum-deposited, is the latter, which requires vacuum film-forming to be carried out in at least two types of light-shielding film material and semi-transmissive film material. However, the manufacturing process is simpler. However, due to the diffraction interference effect of light at the periphery of the pattern, the gray-tone mask type has large variations in light intensity, and it may be difficult to maintain good shape quality especially in areas where the film thickness is large. It is necessary to appropriately select the type of exposure mask according to the shape of the slope desired.

As shown in FIG. 2B3, the color microlens layer 61p selected by the photolithography method is heat-treated, so that the flow-formed color microlens 61s can be obtained while maintaining a good curved surface shape. The heat treatment conditions depend on the thermal characteristics of the colored transparent resin material used for the color microlens, but are usually made to flow at a heating temperature of 100 ° C to 300 ° C. During heat flow, the black matrix 7 functions not only as a light-shielding material but also as a wall material so that the color microlenses are dammed in the pixels to ensure a sufficient color separation and ensure sufficient color separation. Can be made.

  Since the movement of the heat flow of the color microlens material is limited by the wall of the black matrix 7, even with the color microlens layer 61p that has been slightly misaligned in the previous exposure process, A constant position correction is possible. Further, by making the height of the color microlens surrounded by the wall of the black matrix higher than the wall of the black matrix, it is possible to optimize the curved surface shape of the top of the color microlens 61s formed by the heat treatment. It can be inferred that the optimization of the curved surface shape is caused by the surface tension.

  Next, the process for forming the second color microlens will be described with reference to FIGS. The color microlens material 62m for the second color is applied on the substrate on which the color microlens 61s cured by the heat flow of the first color is formed. The color microlens material 62m is a photosensitive material including a specific color pigment having a predetermined spectral transmittance characteristic different from that of the first color and an alkali-soluble resin similar to that of the first color. It is possible to use an acrylic positive type photosensitive resin in which the above resin decomposes and exhibits alkali solubility. The photosensitive colored transparent resin can be applied onto the substrate by the same method and thickness as in the first color.

  Thereafter, the exposure, development process (see FIG. 2 (c2)), and heat flow process (see FIG. 2 (c3)) are sequentially performed in the same manner as the first color to form the second color microlens. . The mechanism by which the color microlenses are formed in accordance with the process is the same, and the third and subsequent colors can be formed in the same manner as in the first and second colors. In the present invention, it is possible to easily cope with a plurality of colors constituting the color microlens being three or more colors, and the present invention can be applied to various color solid-state imaging devices while maintaining the same effects as described above.

  When the aspect ratio is defined as an index representative of the shape of the color microlens 61 s that has been flow-molded by heat treatment, an appropriate aspect ratio can be obtained by investigating the possible conditions of the flow temperature corresponding to the heat treatment temperature that causes heat flow. A range can be defined. Needless to say, the aspect ratio to be actually used is regulated by the dimension example of the color microlens to be incorporated in the color solid-state imaging device, but know the maximum range of the aspect ratio that can be produced by the method according to the present invention. Can do.

  FIG. 6 is a schematic cross-sectional view for defining an aspect ratio representative of the shape of the color microlens of the present invention. Corresponding to the photoelectric conversion element 3, the shape of the color microlens 6 provided through the transparent flattening layer 5 is restricted by the black matrix 7, and the arrows a (lens diameter) and b (lens) And the height of the part). At this time, a value represented by b / a is defined as an aspect ratio. If the aspect ratio is the same as long as similar materials are used, the curvature at the top of the color microlens can be regarded as the same.

  As a result of investigating how the appropriate flow temperature conditions are determined according to the aspect ratio when trying to make a color microlens with the manufacturing method of the present invention by changing the aspect ratio defined as above. Is shown in Table 1 as the formation conditions of the color microlens. The circles in the table indicate conditions under which the shape could be properly manufactured, and the x marks in the table indicate conditions under which the shape could not be manufactured properly. X at all aspect ratios at 120 ° C. means that the heat flow is insufficient, so that the shape after development cannot be completely transferred to the lens shape. At 220 ° C., x at all aspect ratios. Being present indicates that the lens shape has collapsed due to excessive heat flow. Also, if you want to achieve a shape with a low aspect ratio, if you process on the high temperature side, flattening will progress excessively and the lens effect will be reduced, so it is better to heat flow over a relatively low temperature side over time When a shape with a high aspect ratio is to be obtained, it is shown that a better shape can be obtained by processing on the high temperature side and allowing it to flow in as short a time as possible and then cooling and solidifying. .

  FIG. 5 is a schematic cross-sectional view for explaining another example of the manufacturing method of the color microlens of the present invention in the order of steps, where (a) is a black matrix forming stage, and (b1) to (b4) are the first color. (C1) to (c4) show the second color microlens formation step.

As shown in FIG. 5A, the black matrix 7 is formed of a light-shielding material around a position 60 that is a pixel of each color corresponding to the photoelectric conversion element 3 on a one-to-one basis. In advance, the transparent flattening layer 5 that provides a flat and uniform base is formed by, for example, applying a colorless and transparent acrylic resin solution with a thickness of about 0.1 μm and heat-treating it.
Next, the black matrix 7 is formed by performing a general photolithography process in which a light-shielding material imparting photosensitivity to a black material is applied, dried, selectively exposed, developed, and cured by heat treatment. As a result, the pattern can be directly formed.
Further, a method using a dry etching method advantageous for forming a fine pattern is also possible. That is, a pattern to be an etching resist is formed on the light-shielding material that does not require photosensitivity previously formed by a photolithography method similar to the above, and the pattern formation of the light-shielding material is formed by dry etching. be able to. The latter method is particularly suitable for the formation of a miniaturized pattern because the suitability for photolithography and the suitability for dry etching can be shared between the resist material and the light shielding material. In order to particularly reinforce the dry etching resistance, it is possible to form an inorganic film below the resist material and complete the dry etching of the light shielding material into a more favorable shape. It is also possible to form an inorganic film as a light-shielding material in a vacuum, and after forming an etching resist pattern on the upper layer, the lower inorganic light-shielding film can be patterned by dry etching or wet etching.

Next, the process for forming the first color microlens will be described.
As shown in FIG. 5 (b1), the color microlens material 61m is applied and dried on the light receiving surface side substrate of the solid-state imaging device pixel portion on which the black matrix prepared in FIG. 5 (a) is formed. The color microlens material includes a specific color pigment having a predetermined spectral transmittance characteristic, and is made of a material that facilitates dry etching in a later process. Subsequently, for example, an etching resist material 81m containing an acrylic positive type photosensitive resin that decomposes the resin in the light-irradiated region and exhibits alkali solubility is laminated so as to be thicker than the thickness of the black matrix 7. Apply. A spin coating method can be used as the application of the resin onto the substrate.

  The coated and dried etching resist material 81m is exposed and developed, and the etching resist layer 81p selected by the photolithography method corresponds to a predetermined pixel region as shown in FIG. 5 (b2). Leave. For the exposure process, a stepper capable of repeatedly projecting the enlarged pattern of the exposure mask by reducing projection exposure and repeatedly feeding it can be used. In this step, it is natural to guarantee the positional accuracy using a precise alignment mechanism with respect to the control of the position and shape of the etching resist layer with respect to the black matrix, but the first method of manufacturing the color microlens of the present invention described above. The shape can be improved by the same device as the exposure mask described in one example. Further, the behavior in the next heat flow step is also effective in controlling the position and shape of the color microlens in this example.

By using a photomask called a gray mask having an intermediate density region to which transmittance gradation is given as an exposure mask, the cross-sectional shape of the etching resist layer 81p after development and before heat flow is gentler than illustrated. Therefore, flow molding by heat treatment described later can be assisted. The development step is performed using an alkaline developer, for example, an organic alkaline developer aqueous solution such as tetramethylammonium hydroxide (TMAH).

  As shown in FIG. 5B3, the etching resist layer 81p selected by the photolithography method is heat-treated, so that the flow-formed etching resist 81s can be obtained with a good curved surface shape. The heat treatment conditions depend on the thermal characteristics of the transparent resin material used for the etching resist, but are usually caused to flow at a heating temperature of 100 ° C. to 300 ° C. In order to obtain an excellent shape as a mask for the next dry etching by storing the etching resist in the pixel during the heat flow, the rise of the color microlens material in the vicinity of the black matrix 7 is useful, although not shown. That is, since the movement of the heat flow of the etching resist material is limited by the bulge which is an indirect influence of the wall of the black matrix 7, the etching resist layer 81p having a slight misalignment in the previous exposure process is obtained. In addition, it is possible to perform a certain position correction by the heat flow of this process.

As shown in FIG. 5 (b4), a good curved shape formed by the flow-formed etching resist 81s is transferred by transferring the shape of the color microlens material 61m applied to the lower layer by dry etching. A molded color microlens 61d can be obtained. Dry etching is performed mainly on gas such as CF ₄ , C ₄ F _8, etc. under the condition that the etching rate in the film thickness direction is important, and a color microlens having a curved shape similar to the curved shape of the etching resist can be formed. it can. In addition, after the formation of the color microlens, it is possible to appropriately improve the resistance by performing a treatment such as a curing treatment.

  Next, the process for forming the second color microlens will be described with reference to FIGS. On the substrate on which the first color microlens 61d is formed, the second color microlens material 62m is applied and dried. The color microlens material 62m includes a specific color pigment having a predetermined spectral transmittance characteristic different from that of the first color, and is made of a material that facilitates dry etching in a subsequent process. Subsequently, for example, an etching resist material 82m including an acrylic positive type photosensitive resin in which the resin in the region irradiated with light is decomposed to exhibit alkali solubility is laminated and applied (see FIG. 5C1). . Application of the resin on the substrate can be performed by the same method and thickness as in the first color.

  Thereafter, an exposure, a development process (see FIG. 5 (c2)), a heat flow process (see FIG. 5 (c3)), and a dry etching transfer process (see FIG. 5 (c4)) are sequentially performed in the same manner as the first color. Thus, the second color microlens 62d can be formed. The mechanism by which the color microlenses are formed in accordance with the process is the same, and the third and subsequent colors can be formed in the same manner as in the first and second colors. In the present invention, it is possible to easily cope with a plurality of colors constituting the color microlens being three or more colors, and the present invention can be applied to various color solid-state imaging devices while maintaining the same effects as described above.

DESCRIPTION OF SYMBOLS 1 ... Color solid-state image sensor 2 ... Semiconductor substrate 3 ... Photoelectric conversion element 4 ... Light-receiving surface side surface 5 of a solid-state image sensor pixel part, 51 ... Transparent planarization layer 6 ... Color Microlens 7 ... Black matrix 8 ... Colored transparent pixel pattern 9 ... Light passing through thin part of lens edge 60 ... Position 61m, 62m to be pixel of each color ... Application Color microlens materials 61p, 62p that have been selected Color microlens layers 61s, 62s that have been selected by a photolithography method Color microlenses 61d, 62d that have been flow-formed by heat treatment Transfer molding by a dry etching method Color microlenses 81m, 82m, etc., applied etching resist materials 81p, 82p, ... by photolithography Selected etch resist layer 81s, the etching resist which is flow formed by 82 s · · · heat treatment

Claims (6)

  In a solid-state imaging device in which a plurality of microlenses are provided on the light-receiving surface side surface of a solid-state imaging device pixel portion in which a plurality of photoelectric conversion devices are arranged in a plane on a semiconductor substrate. A color microlens made of one colored transparent resin of a plurality of colors having a spectral transmittance characteristic of the above is arranged regularly and continuously with a color microlens made of a colored transparent resin of another color. A color solid-state imaging device, wherein color microlenses of different colors are separated by a light-shielding black matrix pattern lower than the height of the color microlenses.   2. The method of manufacturing a color microlens in a color solid-state imaging device according to claim 1, wherein a black matrix is formed around a position to be a pixel of each color, and then a color microlens material containing an alkali-soluble photosensitive resin is formed. It is applied to the light-receiving surface side of the solid-state imaging device thicker than the thickness of the black matrix, and the color microlens layer corresponding to a predetermined pixel area is selectively left by the photolithography method by exposure and development, and is limited to the black matrix pattern. A method for producing a color microlens, wherein the curved shape of the color microlens is formed by heat treatment using the heat flow behavior of the resin in the pixel.   3. The method of manufacturing a color microlens according to claim 2, wherein the black matrix has a pattern height of 0.3 to 2 [mu] m.   The aspect ratio of the height exceeding the black matrix of the color microlens and the planar size of the color microlens provided surrounded by the black matrix is 0.2-7. A manufacturing method of a color microlens.   2. The method of manufacturing a color microlens in a color solid-state image pickup device according to claim 1, wherein a black matrix is formed around a position to be a pixel of each color, and then the color microlens material is placed on the light receiving surface side of the solid-state image pickup device. After coating and drying, an etching resist material containing an alkali-soluble photosensitive resin is laminated and applied so as to be thicker than the thickness of the black matrix, and a resist pattern corresponding to a predetermined pixel area is formed on the upper layer of the color microlens layer. A desired curved surface shape is formed by a dry etching method after a desired curved shape is formed by heat treatment using the heat flow behavior of the etching resist pattern within the pixel that is selectively left by the lithography method and limited to the black matrix pattern. Is transferred to the underlying color microlens layer and the color microlens Method for manufacturing a color microlens and forming a curved shape.   The method for producing a color microlens according to any one of claims 2 to 5, wherein a plurality of colors constituting the color microlens are three or more colors.