JP2009170562A - Solid-state imaging apparatus, and manufacturing method of solid-state imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state imaging apparatus which has improved sensitivity and superior color reproducibility even when a photodetection portion decreases in area or when light beams transmitted at respective wavelengths are different in light condensing state, and to provide a manufacturing method of microlenses. <P>SOLUTION: Light condensing efficiency is enhanced by providing microlenses differing in height to obtain a solid-state imaging apparatus having high sensitivity and superior color reproducibility. Further, the light condensing efficiency is enhanced by providing microlenses differing in refractive index to obtain a solid-state imaging apparatus having high sensitivity and superior color reproducibility. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device including a plurality of imaging pixels that receive light of a plurality of colors and a method for manufacturing the same.

  Solid-state imaging devices are used in various image input devices such as video cameras, digital still cameras, and facsimiles. As shown in FIG. 15 illustrating the configuration of the conventional solid-state imaging device, the solid-state imaging device is represented by a CCD (Charge-Coupled Devices), a MOS (Metal Oxide Semiconductor), and the like, and converts light into an electronic signal. The light receiving parts are arranged in a matrix form. A color solid-state imaging device including a color filter that reproduces colors is also generally known. The color filter is composed of red (R), green (G), and blue (B) filters, which are called the three principles of light, and is a primary color filter with excellent color development and excellent reproducibility, as well as cyan (C) and magenta. Two types of filters are used: (M), yellow (Y), and green (G) filters, and complementary color filters that are said to be highly sensitive and have a subdued hue. A pattern of any one of the above colors is arranged on each light receiving unit. In such a solid-state imaging device, the area of the light receiving portion has been reduced due to demands for downsizing, higher pixels, and higher resolution. In order to compensate for such a decrease in photoelectric conversion characteristics due to a decrease in the area of the light receiving portion, the inner lens 13 is disposed under the color filter layer, and the micro lens 200 is disposed on the color filter layer, and a region other than the light receiving portion such as a transfer region. It plays the role which condenses the light which injects into the light-receiving part.

In order to increase the light collection efficiency of light incident on the light receiving unit and achieve high sensitivity, the microlens 200 can be formed by controlling the shape and curvature of the microlens 200 to increase the light collection efficiency or improve the sensitivity uniformity. A method has been proposed. For example, in a microlens formation flow based on a thermosoftening resin having photosensitivity, a photoresist pattern is formed by coating, exposure and development, and light irradiation is applied to a part of the microlens 200 before thermal reflow, By changing the softening point from an unirradiated portion, it is possible to make the curvature of the formed microlens 200 different in each microlens portion, each color filter, or the chip surface after thermal reflow (for example, Patent Documents). 1). In addition, in order to control the amount of light incident on the light receiving unit, a solid-state imaging device has been proposed in which the shape of the on-chip microlens is made different according to each color of the color filter layer and the color reproducibility can be improved. . For example, the planar shape of the resist pattern formed on the organic polymer material layer for forming the microlens is made large and small, and can be formed by reflowing it. Alternatively, after the resist pattern is formed, an upper resist film is further applied, leaving the upper resist only on the resist pattern that requires a thickness, and reflowing them together to form a reflow pattern, which is etched back to form an organic polymer. If the material is transferred, microlenses with different shapes can be formed. In addition, after the resist pattern is formed, an upper resist film is further applied, leaving the upper resist only on the resist pattern that requires a thickness, and reflowing them together to form a reflow resist pattern. When transferred onto a molecular material, microlenses with different heights can be formed (see, for example, Patent Document 2).
JP-A-5-75085 JP-A-9-116127

  However, while the area of the light receiving portion is decreasing, it is difficult to collect the light transmitted through each color filter layer in the light receiving portion even when there are microlenses and intralayer lenses. Therefore, in order to collect more light in the light receiving part, the gap between the microlens adjacent in the horizontal and vertical directions is gapless and the microlens adjacent in the diagonal direction is maintained while maintaining the optimal curvature of the microlens. There is a need to form a microlens that has no or no ineffective area that is gapless or narrowed.

  In addition, light that passes through a red (R) color filter that is long-wavelength light, light that passes through a green (G) color filter that is intermediate-wavelength light, and blue ( The light passing through the color filter B) has a different light collection state such as a light collection position and a light collection width in proportion to the wavelength. Therefore, in order to optimize the light collection efficiency for each color, it is necessary to control the cross section and the planar shape of the microlens for each color.

  However, the conventional on-chip microlens forming method and solid-state imaging device have the following problems. In the formation method that changes the curvature of the microlens by the light irradiation part and the non-irradiation part before thermal reflow, and the formation method that reflows by increasing the size of the planar shape of the resist pattern, the horizontal and vertical microlenses are adjacent to each other. It is difficult to control the curvature of a microlens that is gapless, narrowed between adjacent microlenses in the diagonal direction, or gapless. In addition, the upper layer resist film is applied after the resist is formed, the upper layer resist is left only on the resist pattern that requires a thickness, and these are reflowed together. Therefore, it is impossible to form a microlens having a stable curvature after reflow, and mixing is inevitable if an upper layer resist is applied on the lower layer pattern that has not been reflowed and thermally cured.

  Therefore, the present invention solves the problems of the prior art, and even when the area of the light receiving portion is reduced or the light condensing state that transmits each wavelength is different, the solid-state imaging excellent in sensitivity improvement and color reproducibility An object of the present invention is to provide an apparatus and a method for manufacturing a microlens.

  In order to achieve the above object, a method for manufacturing a solid-state imaging device according to the present invention is a method for manufacturing a solid-state imaging device including a plurality of imaging pixels that are arranged in a matrix on a substrate and receive light of a plurality of colors. Forming a first light receiving portion and a second light receiving portion on the substrate, forming a first planarizing film on the first and second light receiving portions, and the first Forming an inner lens at a position corresponding to the first and second light receiving portions on the planarizing film, and forming a second planarizing film so as to surround the inner lens, Forming a first color filter at a position corresponding to the first light receiving portion on the second planarizing film, and a second color filter at a position corresponding to the second light receiving portion; A first lens material layer is disposed on the first color filter, and the second color filter is disposed on the first color filter. Forming a second lens material layer on the filter, forming a lens shape on the first and second lens material layers, and dry etching the lens shape and the lens material layer. And forming a microlens, wherein the second lens material layer and the first lens material layer have different etching rates or refractive indexes.

  Further, in the light receiving portion forming step, a third light receiving portion is further formed, in the color filter forming step, a third color filter is further formed, and in the lens material layer forming step, a third lens material is further formed. Forming a layer, wherein the third lens material layer has a different etching rate or refractive index from the first and second lens material layers.

  The transmission wavelength of the first color filter is longer than the transmission wavelength of the second color filter, and the transmission wavelength of the second color filter is longer than the transmission wavelength of the third color filter. .

  The first lens material layer has an etching rate lower than that of the second lens material layer, and the second lens material layer has an etching rate lower than that of the third lens material layer. .

Further, the first lens material layer has a refractive index larger than that of the second lens material layer, and the second lens material layer has a refractive index larger than that of the third lens material layer. .
Furthermore, the solid-state imaging device of the present invention is a solid-state imaging device including a plurality of imaging pixels that receive a plurality of colors of light arranged in a matrix on the substrate, and the first light-receiving device formed on the substrate. And a second light receiving portion, a first planarizing film formed on the first and second light receiving portions, and the first and second light receiving portions on the first planarizing film. An in-layer lens formed at a position corresponding to the portion, a second planarization film formed so as to surround the intra-layer lens, and the first light receiving unit on the second planarization film, A first color filter formed at a corresponding position, a second color filter formed at a position corresponding to the second light receiving unit, and a first micro formed on the first color filter. A second matrix formed on the lens and the second color filter; A Kurorenzu, wherein the first microlens and the second microlens height, curvature, and wherein at least one of different of refractive index.

  A third light receiving portion formed on the substrate; a third color filter formed on the second planarizing film at a position corresponding to the third light receiving portion; and A third microlens formed on the color filter, wherein the third microlens is different from the first and second microlenses in at least one of height, curvature, and refractive index. It is characterized by.

  The transmission wavelength of the first color filter is longer than the transmission wavelength of the second color filter, and the transmission wavelength of the second color filter is longer than the transmission wavelength of the third color filter. .

  The first color filter is located in a central area of the imaging area, the third color filter is located in a peripheral area of the imaging area, and the second color filter is located in the central area of the imaging area. It is located in a boundary region between the peripheral regions.

The first microlens is higher than the second microlens, and the second microlens is higher than the third microlens.
The first microlens has a higher refractive index than the second microlens, and the second microlens has a higher refractive index than the third microlens.

Further, the arrangement of the first, second and third light receiving parts on the substrate constitutes a primary color Bayer array.
Further, the arrangement of the first, second, and third light receiving portions on the substrate constitutes a primary color stripe arrangement.

  As described above, a solid-state imaging device and a microlens manufacturing method with improved sensitivity and excellent color reproducibility are provided even when the area of the light receiving portion is reduced or the light condensing state of light transmitted through each wavelength is different. Can do.

  As described above, by providing microlenses having different heights, it is possible to realize a solid-state imaging device with high light collection efficiency and high sensitivity and color reproducibility. In addition, by providing microlenses having different refractive indexes, it is possible to realize a solid-state imaging device with high light collection efficiency and high sensitivity and excellent color reproducibility.

The solid-state imaging device according to the present invention has a microlens formed using different materials.
Specifically, a solid-state imaging device according to the present invention receives a semiconductor substrate, a plurality of first imaging pixels that are arranged in a matrix on the semiconductor substrate and receive long-wavelength light, and intermediate-wavelength light. A plurality of second imaging pixels and a plurality of third imaging pixels that receive light having a short wavelength, and the plurality of first imaging pixels are arranged at positions corresponding to the light receiving portions formed on the substrate. A second planarizing film is formed on the first planarizing film and the intralayer lens, and a long wavelength is formed on the second planarizing film. Color filters that transmit the light of the long wavelength light are respectively formed on the color filters that transmit the light of the long wavelength, and each of the plurality of second imaging pixels includes: A layer formed by interposing a first planarizing film at a position corresponding to the light receiving portion formed on the substrate A second flattening film is formed on the lens, the first flattening film, and the in-layer lens, and a color filter that transmits an intermediate wavelength of light is formed on the second flattening film. And a second microlens made of a material different from the first microlens that transmits light having an intermediate wavelength on the color filter that transmits light having a wavelength of a plurality of, An in-layer lens formed by interposing a first planarizing film at a position corresponding to the photodiode formed thereon, and a second planarizing film on the first planarizing film and the in-layer lens. A first microlens that is formed and has a color filter that transmits short-wavelength light on the second planarizing film and that transmits short-wavelength light on the color filter that transmits short-wavelength light. Third microlens made of different material Characterized in that it has respectively.

  By using different materials, the height of the microlens after transfer, the size and curvature of the microlens can be made different, and the color filter layer that transmits the long wavelength light and the wavelength of the intermediate light are transmitted. A microlens having an optimal shape can be formed on the color filter layer corresponding to the different wavelengths of the color filter layer and the color filter layer transmitting the short wavelength light. In addition, by having different materials, it becomes possible to form microlenses having different widths, heights, and curvatures after transfer. Therefore, more light can be condensed on the light receiving unit, and sensitivity can be improved. In addition, since the shape of the microlens can be easily controlled by using different materials, it is possible to suppress the occurrence of variations in line density and unevenness in sensitivity.

  The method for forming a microlens in the method for manufacturing a solid-state imaging device according to the present invention is based on a first macrolens shape that transmits long-wavelength light on a color filter layer that transmits long-wavelength light. A step of forming a lens material layer, and a step of forming a second lens material layer that is a base of the second microlens shape that transmits the wavelength of the intermediate light on the color filter layer that transmits the light of the intermediate wavelength. And a step of forming a third lens material layer that is a base of the third microlens shape that transmits light of a short wavelength on a color filter layer that transmits light of a short wavelength, and on the lens material layer The method includes a step of forming a lens shape and a step of performing etching by dry etching to transfer the lens shape to the lens material layer.

  In the solid-state imaging device of the present invention, the lens shape on the lens material layer, the first lens material layer that is the basis of the first microlens shape on the color filter layer that transmits long-wavelength light, and the intermediate A second lens material layer that is the origin of the second microlens shape on the color filter layer that transmits light of the wavelength of the third, and an element of the third microlens shape on the color filter layer that transmits light of the short wavelength It is preferable that the third lens material layers become different materials with different etching rates. By having materials with different etching rates, the height, size and curvature of the microlens shape can be made different after transfer.

  For example, the lens shape on the lens material layer, the third lens material layer that is the origin of the third microlens shape on the color filter layer that transmits light of short wavelength, and the light of intermediate wavelength are transmitted. The etching rate of the second lens material layer that is the basis of the second microlens shape on the color filter layer that is the first is the first microlens shape that is the basis of the first microlens shape on the color filter layer that transmits light having a long wavelength. A material having an etching rate faster than the etching rate of one lens material layer is preferable. Furthermore, the etching rate of the third lens material layer, which is the basis of the lens shape on the lens material layer and the third microlens shape on the color filter layer that transmits light with a short wavelength, is light with an intermediate wavelength. A material having an etching rate faster than the etching rate of the second lens material layer that is the basis of the second microlens shape on the color filter layer that transmits light is preferable. Furthermore, the etching rate of the lens shape on the lens material layer is faster than the etching rate of the third lens material layer that is the basis of the third microlens shape on the color filter layer that transmits light having a short wavelength. A material having a rate is preferable.

  Further, the lens-shaped material on the lens material layer has the same etching rate as the third lens material layer that is the basis of the third microlens shape on the color filter layer that transmits light having a short wavelength. The material may be used.

By adopting such a configuration, it is possible to form a microlens having an optimal shape that enhances the collection of light incident on the light receiving portion on the color filter layer that transmits light of different wavelengths.
In the solid-state imaging device of the present invention, the first lens material layer that is the basis of the first microlens shape on the color filter layer that transmits light of a long wavelength, and the color filter layer that transmits the wavelength of intermediate light The second lens material layer that is the source of the second microlens shape and the third lens material layer that is the source of the third microlens shape on the color filter layer that transmits light of a short wavelength are respectively It is preferable to have materials having different refractive indexes. Since the lens material layers have different refractive indexes, microlenses having different refractive indexes can be formed on each color filter layer after transfer.

  For example, the refractive index of the second lens material layer that is the basis of the second microlens shape on the color filter layer that transmits the intermediate light wavelength, and the first on the color filter layer that transmits the long wavelength light. The refractive index of the first lens material layer that is the source of the microlens shape is the refractive index of the third lens material layer that is the source of the third microlens shape on the color filter layer that transmits light having a short wavelength. It is preferable to have a material with a higher refractive index. Furthermore, the refractive index of the first lens material layer that is the basis of the first microlens shape on the color filter layer that transmits light having a long wavelength is the second refractive index on the color filter layer that transmits the wavelength of intermediate light. It is preferable to use a material having a refractive index higher than that of the second lens material layer that is the source of the microlens shape.

With such a configuration, it becomes possible to form microlenses with different refractive indexes on color filters that transmit light of different wavelengths, and the light collection state of light incident on the light receiving portion of each imaging pixel is different for each wavelength. Can be optimized.
(Embodiment 1)
Hereinafter, the solid-state imaging device and the manufacturing method according to the first embodiment of the present invention will be described with reference to FIGS.

  1A and 1B are diagrams for explaining the configuration of a solid-state imaging device according to the first embodiment. FIG. 1A shows a planar arrangement, FIG. 1B shows a cross-sectional configuration taken along line Ib-Ib, and FIG. (c) has shown the cross-sectional structure in the Ic-Ic line | wire of Fig.1 (a). In FIG. 1B and FIG. 1C, only three pixels are shown.

  As shown in FIG. 1B and FIG. 1C, the solid-state imaging device according to the embodiment of the present invention includes a first micro lens 35A, a second micro lens 35B, and a third micro lens. It is characterized by having a material with a different etch rate in 35C.

  First, as illustrated in FIG. 1, the solid-state imaging device according to the first embodiment includes a plurality of first imaging pixels 11 </ b> A that receive red (R) light, which is long-wavelength light, and green, which is an intermediate light wavelength. A plurality of second imaging pixels 11 </ b> B that receive light (G) and a plurality of third imaging pixels 11 </ b> C that receive blue (B) light having a short wavelength are arranged on the semiconductor substrate 10 with a primary color Bayer array. It is formed in a matrix form.

  Each imaging pixel has a light receiving portion 12 formed on the semiconductor substrate 10 and a transfer electrode 21 formed on the semiconductor substrate 10 adjacent to the light receiving portion 12 with an insulating film 22 interposed therebetween. Yes.

Further, the upper surface and the side surface of each transfer electrode 21 are covered with a light shielding film 23 and further covered with a first planarization film 24 made of boron phosphorus silicate glass (BPSG) or the like.
Next, in-layer lenses 13 are respectively formed at positions corresponding to the respective light receiving portions 12 on the first planarization film 24. A second flattening film 31 made of, for example, an acrylic transparent resin is formed on and surrounding the intralayer lens 13, and is located on the second flattening film 31 at a position corresponding to each light receiving unit 12. Are formed with color filters 14A, 14B, and 14C that transmit light received by each imaging pixel.

  Next, on the color filter 14A that passes red (R) light that is long-wavelength light received by the first imaging pixel 11A, for example, a styrene resin having an etching rate of 25.3 nm / sec. The first microlens 35A is formed, and the etching rate is 24, for example, on the color filter 14B that transmits green (G) light, which is intermediate wavelength light received by the second imaging pixel 11B. A second microlens 35B made of an acrylic resin having a wavelength of .2 nm / sec is formed, and an etching rate of, for example, 23 is provided on the color filter 14C that transmits blue (B) light, which is short-wavelength light. A third microlens 35C made of an acrylic resin having a thickness of 0.0 nm / sec is formed.

  Next, the microlens shape formed in the upper layer of each imaging pixel in the present embodiment will be described with reference to the drawings. 2 is a cross-sectional view illustrating the configuration of the microlens according to the first embodiment of the present invention, and FIG. 3 is a plan view illustrating the configuration of the imaging pixel and the microlens according to the first embodiment of the present invention.

  For example, the vertical width a, the horizontal width b, and the diagonal width c of the first microlens 35A are diagonal to the vertical width a and the horizontal width b of the first imaging pixel 35A. It is the same as the width c in the direction, and the height h1 is about 1.0 μm. For example, the vertical width a and the horizontal width b of the second microlens are the same as the vertical width a and the horizontal width b of the second imaging pixel 35B, but the four corners in the diagonal direction. The gap d is about 0.1 μm, the diagonal width c ′ of the second microlens 35B is narrower, and the height h2 is about 1.1 μm than the diagonal width c of the second imaging pixel 11B. It is. For example, the vertical width a and the horizontal width b of the third microlens are the same, but there are gaps d of about 0.2 μm at the four corners in the diagonal direction, and the diagonal direction of the third imaging pixel 11C. The diagonal direction c ″ of the third microlens 35C is narrower and the height h3 is about 1.2 μm compared to the width c of the above. Thus, the light incident on the light receiving unit 12 of each imaging pixel is efficiently collected. High sensitivity can be realized.

  Here, the configuration in which the height of the microlens is different for each light reception wavelength has been described, but the light collection efficiency can be improved even if the curvature is different for each light reception wavelength. In addition, it is possible to optimize the shape of the microlens for each light receiving wavelength, thereby suppressing variations in line density and uneven sensitivity.

Below, the manufacturing method of the solid-state imaging device concerning this embodiment is demonstrated with reference to FIGS.
4, 5, and 6 are process cross-sectional views illustrating the method for manufacturing the solid-state imaging device according to Embodiment 1 of the present invention.

  First, as shown in FIGS. 4A and 4B, a light receiving portion 12, an insulating film 22, and a transfer electrode 21 are formed on a semiconductor substrate 10 by a known method. Subsequently, after forming the light shielding film 23 covering the transfer electrode 21, the first planarizing film 24 is formed on the semiconductor substrate 10, and the inner lens 13 is formed on the formed first planarizing film 24. Form. Subsequently, the second planarizing film 31 is formed so as to cover the upper layer lens 13, and then the first light that transmits red light, which is long-wavelength light, is transmitted onto the second planarizing film 31. The color filter 14A, the second color filter 14B that transmits green that is intermediate light, and the third color filter 14C that transmits blue light that is short-wavelength light are formed according to the position of each imaging pixel. .

Next, as shown in FIG. 4C, a pre-bake is performed after applying a photoresist 15 as a base of the first microlens shape on each color filter.
Next, as shown in FIG. 5A, the region of the first color filter is masked and exposed in accordance with the position of the first imaging pixel 11A that receives red light, which is long wavelength light.

Next, as shown in FIG. 5B, the exposed photoresist 15 is removed by development to form a first lens material layer 51 on the first color filter 14A.
Similarly, as shown in FIG. 5C, the second color filter 14B is positioned on the second color filter 14B in accordance with the position of the second imaging pixel 11B that receives green light that is intermediate wavelength light. The second lens material layer 52 is formed, and as shown in FIG. 6A, the third color filter 14C is aligned with the position of the third imaging pixel 11C that receives blue light, which is short-wavelength light. A third lens material layer 53 is formed thereon. Here, the first lens material layer 51, the second lens material layer 52, and the third lens material layer 53 are material layers having different etch rates.

  Next, as shown in FIG. 6B, for example, an etching rate is formed on the first lens material layer 51, the second lens material layer 52, and the third lens material layer 53 using a known method. A lens shape 41 made of acrylic resin having 23.0 nm / sec is formed in accordance with the position of each imaging pixel.

  Next, as shown in FIG. 6C, the lens shape 41 is etched by dry etching using a known method, and transferred to each lens material layer. This etching is, for example, anisotropic reactive ion etching using a fluorine-based gas.

  Since the first lens material layer 51, the second lens material layer 52, and the third lens material layer 53 have different etch rates, the height and size of each microlens shape is obtained by etching in FIG. And different curvatures can be realized.

The order of forming the first lens material layer 51, the second lens material layer 52, and the third lens material layer 53 made of materials having different etching rates may be arbitrarily changed.
In the first embodiment, the first lens material layer 51, the area of the light receiving unit 12, the shape of the transfer electrode 21, the insulating film 22 and the light shielding film 23, the distance between the microlens and the light receiving unit 21, and the like are changed. The second lens material layer 52 and the third lens material layer 53 may be interchanged as necessary.

Furthermore, in order to make the height, size, and curvature of the microlens shape different as necessary, lens materials having different etching rates other than those described above may be used.
In addition, the lens shape and the lens material layer may have four different etching rates, or the lens shape and any one of the lens material layers may have the same etching rate, and materials having three different etching rates may be used. It may be used.

  Further, if necessary, the lens shape 41 and the first lens material layer 51 are made of a material having the same etching rate, and the second lens material layer 52 and the third lens material layer 53 are made of a material having the same etching rate. Different etch rates of different types may be used.

  In the primary color Bayer arrangement of the first embodiment, the lens materials of the second imaging pixel 11B sandwiched between the first imaging pixel 11A and the second imaging pixel 11B sandwiched between the first imaging pixel 11A in the vertical direction. The layer 52 is preferably made of materials having different etching rates.

With this configuration, it is possible to reduce the sensitivity unevenness caused by the difference in output, which may occur when the light transmitted through the adjacent color filters of different wavelengths enters the second imaging pixel, using a material having a different etching rate. By forming the lens shape optimally, it is possible to arbitrarily eliminate the output difference, and it is possible to prevent the occurrence of uneven sensitivity due to such a cause.
(Embodiment 2)
7A and 7B are diagrams illustrating the configuration of the solid-state imaging device according to the second embodiment. FIG. 7A illustrates a planar arrangement, FIG. 7B illustrates a cross-sectional configuration taken along line Ib-Ib, and FIG. (c) has shown the cross-sectional structure in the Ic-Ic line | wire of Fig.7 (a). In FIG. 7, the same components as those in FIG.

  As shown in FIGS. 7B and 7C, the solid-state imaging device according to the embodiment of the present invention includes a first microlens 35A, a second microlens 35B, and a third microlens. 35C has a material with a different refractive index. Also, the height and curvature of each may be the same.

  Hereinafter, the configuration of the solid-state imaging device according to the present embodiment will be described together with the manufacturing method with reference to the drawings. 8, 9, and 10 are process cross-sectional views illustrating a method for manufacturing a solid-state imaging device according to Embodiment 2 of the present invention. 8, 9, and 10, the same components as those in FIGS. 4, 5, and 6 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 8A, a photoresist 18 having a refractive index n = 1.58, for example, which is the basis of the first microlens shape is applied on each color filter and then prebaked.

Next, as shown in FIG. 8B, the region of the first color filter 14A is masked and exposed in accordance with the position of the first imaging pixel 11A that receives red light having a long wavelength. .
Next, as shown in FIG. 8C, the exposed photoresist 18 is removed by development, so that the first lens material having a refractive index n = 1.58 on the first color filter. Layer 61 is formed.

  Similarly, as shown in FIG. 9A, in accordance with the position of the second imaging pixel 11B that receives green light, which is light having an intermediate wavelength, on the second color filter 14B, For example, a second lens material layer 62 having a refractive index n = 1.61 is formed, and as shown in FIG. 9B, the third imaging pixel 11C that receives blue light, which is short-wavelength light. For example, a third lens material layer 63 having a refractive index n = 1.62 is formed on the third color filter 14C.

  Next, as shown in FIG. 9C, an acrylic resin is formed on the first lens material layer 51, the second lens material layer 52, and the third lens material layer 53 using a known method. The lens shape 41 is formed in accordance with the position of each imaging pixel.

Next, as shown in FIG. 10, the lens shape 41 is etched by dry etching using a known method, and transferred to each lens material layer.
As a result, microlenses having different refractive indexes can be formed, and the condensing state of light incident on the light receiving unit 12 of each imaging pixel can be optimized for each different wavelength.

Note that the order of forming the first lens material layer 61, the second lens material layer 62, and the third lens material layer 63 made of materials having different refractive indexes may be arbitrarily changed.
In the second embodiment, when the area of the light receiving unit 12, the shape of the transfer electrode 21, the insulating film 22 and the light shielding film 23, the distance between the microlens and the light receiving unit 12, or the like changes, the first lens material layer 61. The second lens material layer 62 and the third lens material layer 63 may be interchanged as necessary.

  Furthermore, when the area of the light receiving unit 12, the shape of the transfer electrode 21, the insulating film 22 and the light shielding film 23, the distance between the microlens and the light receiving unit 12, and the like change as necessary, the refractive index other than the above differs. A lens material may be used.

  In the second embodiment, the configuration in which the lens material layer is provided with three types of materials having different refractive indexes has been described. However, the configuration may be provided with two types of materials having different refractive indexes as necessary.

Moreover, in the structure provided with the material from which two types of refractive indexes differed as needed, you may change the combination with which a lens material layer is equipped.
In the primary color Bayer arrangement of the second embodiment, lens materials of the second imaging pixel 11B sandwiched between the first imaging pixel 11A and the second imaging pixel 11B sandwiched between the third imaging pixel 11C in the vertical direction. The layer 52 is preferably made of materials having different refractive indexes.

In addition to changing the refractive index as in the present embodiment and changing the etching rate as in the first embodiment, more optimal light collection characteristics can be obtained.
With this configuration, the sensitivity variation due to the output difference that appears to be greatly different when the light transmitted through the adjacent color filters of different wavelengths is incident on the second imaging pixel can be reduced. By forming it, it becomes possible to arbitrarily eliminate the output difference, and it is possible to prevent the occurrence of sensitivity unevenness due to such a cause.
(Embodiment 3)
Furthermore, the solid-state imaging device according to the present invention can also reduce sensitivity unevenness due to an output difference between regions caused by a difference in the amount of incident light between the central region and the peripheral region in the effective pixel region.

  The solid-state imaging device according to the present embodiment divides an effective pixel region into a plurality, and has microlenses made of different materials for the plurality of effective pixel regions on a color filter layer positioned on the plurality of effective pixel regions. It is characterized by the configuration.

Here, an example in which different materials in the present embodiment are made of materials having different etching rates will be described.
The configuration of the solid-state imaging device according to this embodiment will be described below with reference to the drawings.

  11A and 11B are diagrams illustrating the configuration of the solid-state imaging device according to the third embodiment. FIG. 11A illustrates a planar configuration, and FIG. 11B illustrates a cross-sectional configuration. In FIG. 11, the same components as those in FIG.

  For example, as illustrated in FIGS. 11A and 11B, the solid-state imaging device according to the embodiment of the present invention includes a central region 111 and a central portion obtained by selectively dividing a plurality of effective pixel regions 100. The microlenses having different etching rates in the respective regions are provided on the region 112 between the peripheral portion and the peripheral portion region 113.

  With this configuration, microlenses having different sizes and different heights can be formed in each region, and the difference in the amount of light incident on the central portion and the peripheral portion in the effective pixel region can be suppressed, thereby reducing sensitivity unevenness.

12, 13, and 14 are process cross-sectional views illustrating a method for manufacturing a solid-state imaging device according to Embodiment 3 of the present invention.
In addition, the manufacturing method in this embodiment is based on the manufacturing method of Embodiment 1, and description here is abbreviate | omitted.

  Furthermore, according to the present embodiment, as described in the second embodiment, materials having different refractive indexes may be used. The same effect can be obtained by forming microlenses having different refractive indexes in each region.

  Note that the first lens material layer 81 in the central region 111 made of a material having a different etching rate, the second lens material layer 82 in the region between the central portion and the peripheral portion, and the third lens material layer in the peripheral region. The formation order of 83 may be arbitrarily changed.

Furthermore, in the present embodiment, the number of divided regions in each region of the effective pixel region portion may be changed as necessary. Thereby, the incident light quantity of each area | region can be adjusted easily.
In the first embodiment, the second embodiment, and the third embodiment, the material used for the lens formation 41 and the lens material layer may be a novolac resin, a silicon resin, a polyimide resin, or a fluorine resin, which is a light transmitting resin. Good.

In the first embodiment, the second embodiment, and the third embodiment, the lens material layer and the lens formation are formed using an organic resist, but an inorganic resist may be used.
In the first embodiment, the second embodiment, and the third embodiment, the configuration in which the in-layer lens 13 for condensing incident light on each light receiving unit 12 has an upward convex structure has been described. The same effect can be obtained also in a solid-state imaging device having a downward convex structure or a solid-state imaging device without the in-layer lens 13.

  In the first, second, and third embodiments, the first imaging pixel 11A that receives long-wavelength light, the second imaging pixel 11B that receives intermediate light, and the first imaging pixel 11B that receives short-wavelength light. Although the example of the primary color Bayer arrangement in which the three imaging pixels 11C are arranged in a checkered pattern is shown, the first imaging pixel 11A, the second imaging pixel 11B, and the third imaging pixel 11C are also arranged in a stripe arrangement. Similar effects can be obtained.

  Furthermore, in the first embodiment, the second embodiment, and the third embodiment, the case where the color filter is a primary color filter of three colors is described, but the number of colors of the color filter is not limited. Further, the manufacturing method according to the present invention can be similarly applied to a complementary color filter other than the primary color filter.

In the first embodiment, the second embodiment, and the third embodiment, a material having a different etching rate and a material having a different refractive index may be combined as necessary.
Furthermore, in the first embodiment, the second embodiment, and the third embodiment, the lens material layer may be the same height. By aligning the lens material layers at the same height, it is possible to suppress coating unevenness that occurs when forming a lens shape.

  Further, in the first embodiment, the second embodiment, and the third embodiment, the example of the manufacturing method of the CCD solid-state imaging device has been described. However, the manufacturing method according to the present invention is similar to the MOS solid-state imaging device. Needless to say, it can be applied.

  The present invention is excellent in sensitivity improvement and color reproducibility, and is useful for a solid-state imaging device including a plurality of imaging pixels that receive light of a plurality of colors, a manufacturing method thereof, and the like.

2A and 2B illustrate a configuration of a solid-state imaging device according to Embodiment 1. Sectional drawing explaining the structure of the micro lens which concerns on Embodiment 1 of this invention. FIG. 3 is a plan view illustrating the configuration of an imaging pixel and a microlens according to the first embodiment of the invention. Process sectional drawing which shows the manufacturing method of the solid-state imaging device concerning Embodiment 1 of this invention Process sectional drawing which shows the manufacturing method of the solid-state imaging device concerning Embodiment 1 of this invention Process sectional drawing which shows the manufacturing method of the solid-state imaging device concerning Embodiment 1 of this invention FIG. 6 is a diagram illustrating a configuration of a solid-state imaging device according to a second embodiment. Process sectional drawing which shows the manufacturing method of the solid-state imaging device concerning Embodiment 2 of this invention Process sectional drawing which shows the manufacturing method of the solid-state imaging device concerning Embodiment 2 of this invention Process sectional drawing which shows the manufacturing method of the solid-state imaging device concerning Embodiment 2 of this invention FIG. 6 is a diagram illustrating a configuration of a solid-state imaging device according to a third embodiment. Process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on Embodiment 3 of this invention. Process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on Embodiment 3 of this invention. Process sectional drawing which shows the manufacturing method of the solid-state imaging device which concerns on Embodiment 3 of this invention. The figure explaining the structure of the conventional solid-state imaging device

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Semiconductor substrate 11A 1st image pick-up pixel 11B 2nd image pick-up pixel 11C 3rd image pick-up pixel 12 Light-receiving part 13 In-layer lens 14A Color filter 14B Color filter 14C Color filters 15, 18, 71 Photoresist 21 Transfer electrode 22 Insulating film 23 light shielding film 24 first planarizing film 31 second planarizing film 35A first microlens 35B second microlens 35C third microlens 41 lens shapes 51, 61, 81 first lens material layer 52 , 62, 82 Second lens material layer 53, 63, 83 Third lens material layer 100 Effective pixel region 111 Central region 112 Region between central portion and peripheral portion 113 Peripheral region 200 Microlens

Claims (13)

A method for manufacturing a solid-state imaging device including a plurality of imaging pixels that are arranged in a matrix on a substrate and receive light of a plurality of colors,
Forming a first light receiving portion and a second light receiving portion on the substrate;
Forming a first planarization film on the first and second light receiving parts;
Forming an in-layer lens on the first planarizing film at a position corresponding to the first and second light receiving parts;
Forming a second planarization film so as to surround the in-layer lens;
Forming a first color filter at a position corresponding to the first light receiving portion on the second planarizing film, and a second color filter at a position corresponding to the second light receiving portion;
Forming a first lens material layer on the first color filter and forming a second lens material layer on the second color filter;
Forming a lens shape on the first and second lens material layers;
Forming a microlens by performing dry etching on the lens shape and the lens material layer,
The method for manufacturing a solid-state imaging device, wherein the second lens material layer and the first lens material layer have different etching rates or refractive indexes. In the light receiving portion forming step, a third light receiving portion is further formed,
In the color filter forming step, a third color filter is further formed,
In the lens material layer forming step, further forming a third lens material layer,
2. The method of manufacturing a solid-state imaging device according to claim 1, wherein the third lens material layer has a different etching rate or refractive index from the first and second lens material layers.   The transmission wavelength of the first color filter is longer than the transmission wavelength of the second color filter, and the transmission wavelength of the second color filter is longer than the transmission wavelength of the third color filter. A manufacturing method of the solid-state imaging device according to 2.   The first lens material layer has an etching rate lower than that of the second lens material layer, and the second lens material layer has an etching rate lower than that of the third lens material layer. A method for manufacturing the solid-state imaging device according to 3.   The refractive index of the first lens material layer is larger than that of the second lens material layer, and the refractive index of the second lens material layer is larger than that of the third lens material layer. A method for manufacturing the solid-state imaging device according to 3. A solid-state imaging device including a plurality of imaging pixels that receive light of a plurality of colors arranged in a matrix on a substrate,
A first light receiving portion and a second light receiving portion formed on the substrate;
A first planarization film formed on the first and second light receiving parts;
An in-layer lens formed on the first planarizing film at a position corresponding to the first and second light receiving parts;
A second planarization film formed so as to surround the in-layer lens;
A first color filter formed at a position corresponding to the first light receiving portion on the second planarizing film, and a second color filter formed at a position corresponding to the second light receiving portion; ,
A first microlens formed on the first color filter and a second microlens formed on the second color filter;
The solid-state imaging device, wherein the first microlens and the second microlens are different in at least one of height, curvature, and refractive index. A third light receiving portion formed on the substrate;
A third color filter formed on the second planarizing film at a position corresponding to the third light receiving portion;
A third microlens formed on the third color filter,
The solid-state imaging device according to claim 6, wherein the third microlens is different from the first and second microlenses in at least one of height, curvature, and refractive index.   The transmission wavelength of the first color filter is longer than the transmission wavelength of the second color filter, and the transmission wavelength of the second color filter is longer than the transmission wavelength of the third color filter. The solid-state imaging device according to 7.   The first color filter is located in a central area of the imaging area, the third color filter is located in a peripheral area of the imaging area, and the second color filter is located in the central area and the periphery of the imaging area The solid-state imaging device according to claim 7, wherein the solid-state imaging device is located in a boundary region between the regions.   The solid-state imaging according to claim 8 or 9, wherein the first microlens is higher than the second microlens, and the second microlens is higher than the third microlens. apparatus.   The first microlens has a higher refractive index than the second microlens, and the second microlens has a higher refractive index than the third microlens. The solid-state imaging device according to any one of 10.   The solid-state imaging device according to any one of claims 8 to 11, wherein the arrangement of the first, second, and third light receiving units on the substrate constitutes a primary color Bayer array.   The solid-state imaging device according to any one of claims 8 to 11, wherein the first, second, and third light receiving portions are arranged on a substrate in a primary color stripe arrangement.

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