JP2020170071A - Filter for solid-state imaging element, solid-state imaging element, manufacturing method of filter for solid-state imaging element, and manufacturing method of solid-state imaging element - Google Patents

Abstract

To provide a filter for solid-state imaging elements, a solid-stage imaging element, a manufacturing method of the filter for solid-stage imaging elements, and a manufacturing method of the solid-stage imaging element, with which it is possible to have both visible light image acquisition and infrared sensor function with a single solid-stage imaging element.SOLUTION: The filter comprises three-color filters located on light incidence side relative to photoelectric conversion elements 11G, 11R, 11B for respective colors, and an infrared pass filter 12P located on light incidence side relative to a photoelectric conversion element 11P for infrared. The infrared pass filter 12P is a laminate composed of two-color filter elements 12P1, 12P2 arranged at positions mutually adjoining one side, and a color element 12P2 in the upper laminate layer is a pixel arranged at a position diagonal to the pixels of the same color, with the filter element of each color being less than or equal in film thickness to the color filter of the same color as the filter element and composed from the same material as the color filter.SELECTED DRAWING: Figure 1

Description

The present invention relates to a filter for a solid-state image sensor, a solid-state image sensor including a filter for a solid-state image sensor, a method for manufacturing a filter for a solid-state image sensor, and a method for manufacturing a solid-state image sensor.

Solid-state image sensors such as CMOS image sensors and CCD image sensors are used in smartphones, video cameras, in-vehicle cameras, and the like.
The solid-state image sensor includes a plurality of photoelectric conversion elements regularly arranged in the horizontal and vertical directions on a two-dimensional plane, and it is common to form a pair of color separation color filters and microlenses. Structure (see, for example, Patent Document 1).
In addition, since the silicon photodiode that forms the solid-state image sensor is also sensitive to infrared rays, the infrared rays that pass through each color filter become noise during photoelectric conversion, so infrared cut filters are often used (infrared cut filters). For example, see Patent Document 2).

On the other hand, as a security system using infrared rays, an iris recognition system and a 3D face recognition system having high security have been attracting attention and are being actively developed, and in particular, their application to mobile terminals such as smartphones is expanding.

Japanese Patent No. 3719036 Japanese Patent No. 4644423

However, as in Patent Document 1 and Patent Document 2, mounting two image sensor cameras and two infrared sensors for image acquisition increases the number of parts and leads to an increase in cost. In addition, in smartphones and the like, the display occupancy rate for the housing is increasing due to the recent bezel-less operation, so it is necessary to mount a solid-state image sensor at the expense of a part of the screen, which gives freedom in terms of design and design. There was a problem that the degree was reduced.

Therefore, the present invention relates to a filter for a solid-state image sensor, a solid-state image sensor, a method for manufacturing a filter for a solid-state image sensor, and a solid-state image sensor, which can have both visible light image acquisition and an infrared sensor function with one solid-state image sensor. An object is to provide a manufacturing method.

In order to solve the above problems, the filter for a solid-state image sensor of the present invention relates to a color filter containing red pixels and blue pixels located on the incident side of light with respect to the first photoelectric conversion element and a second photoelectric conversion element. An infrared pass filter located on the incident side of light is provided, and the blue pixel and the red pixel are adjacent to each other on one side of each other, and the infrared pass filter has two pass elements, red and blue, laminated. The pass elements laminated on the upper layer of the infrared pass filter are characterized by having the same color as the diagonally located color filter.

According to the above configuration, by arranging the pass elements laminated on the upper layer of the infrared pass filter so as to have the same color as the color filter located diagonally, it is possible to have both visible light image acquisition and an infrared sensor function. it can. In addition, the amount of fluctuation in the film thickness in the pixel can be minimized.

Further, in one aspect of the present invention, the unit including the red pixel, the blue pixel, the infrared path filter, and the green pixel is repeatedly arranged in the horizontal direction and the vertical direction on a two-dimensional plane as one unit. Being done.

Further, in one aspect of the present invention, the infrared pass filter has a thickness of the red pixel and the blue pixel or more.

Further, the solid-state image sensor of the present invention is characterized by including a photoelectric conversion element and a filter for the solid-state image sensor according to any one of the above.

Further, the method for manufacturing a filter for a solid-state imaging device of the present invention includes a color filter containing red pixels and blue pixels located on the incident side of light with respect to the first photoelectric conversion element, and incident light with respect to the second photoelectric conversion element. A method for manufacturing a filter for a solid-state imaging element including an infrared pass filter located on the side. The infrared pass filter is a laminate of two pass elements, red and blue, and the pass element is The film thickness is equal to or less than that of the color filter of the same color as the path element, and the film is made of the same material as the color filter. The color filter of each color is formed in a separate process, and the color filter of each color is formed. And, the path element of the same color as the color filter is formed in the same process.

Further, in the method for manufacturing a solid-state image sensor of the present invention, a step of forming a photoelectric conversion element and the above-mentioned method for manufacturing a filter for a solid-state image sensor are used for a solid-state image sensor on the incident side of light of the photoelectric conversion element. It is characterized by including a step of forming a filter.

According to the above configuration, the red and blue two-color pass elements constituting the infrared pass filter and the corresponding two-color pixels are made of the same material. Therefore, it is possible to suppress the occurrence of a difference depending on the constituent material between the processing conditions suitable for the color filter and the processing conditions suitable for the infrared pass filter. In addition, it is possible to prevent a difference depending on the constituent material from occurring between the usage environment suitable for the color filter and the usage environment suitable for the infrared pass filter.

According to one embodiment of the present invention, a filter for a solid-state image sensor, a solid-state image sensor, a method for manufacturing a filter for a solid-state image sensor, and a method for manufacturing a filter for a solid-state image sensor, which can have both visible light image acquisition and an infrared sensor function with one solid-state image sensor, and , A method for manufacturing a solid-state image sensor can be provided.

It is an exploded perspective view which partially shows the layer structure of the solid-state image sensor in 1st Embodiment. It is a schematic cross-sectional view at the position of line II-II in FIG. It is a graph explaining the light absorption and light transmission by the red filter element and the blue filter element which make up an infrared pass filter. It is a graph which shows an example of the transmission spectrum of an infrared pass filter. It is a figure which shows typically the manufacturing method of the color filter in the conventional Bayer arrangement. It is a figure which shows typically the manufacturing method of the filter for a conventional solid-state image sensor. It is a figure which shows typically the manufacturing method of the filter for a solid-state image sensor in 1st Embodiment. It is a figure which shows typically the manufacturing method of the filter for a solid-state image sensor in the 2nd Embodiment. It is a figure which shows typically the layer structure of the filter for a solid-state image sensor in 3rd Embodiment.

(First Embodiment)
Hereinafter, a first embodiment of a filter for a solid-state image sensor, a solid-state image sensor, a method for manufacturing a filter for a solid-state image sensor, and a method for manufacturing a solid-state image sensor according to the present invention will be described with reference to FIGS. 1 to 8. To do. FIG. 1 is an exploded perspective view partially showing the layer structure of the solid-state image sensor in the present embodiment. FIG. 2 is a schematic cross-sectional view taken along the line II-II in FIG.

As shown in FIGS. 1 and 2, the solid-state image sensor of the present embodiment includes a solid-state image sensor filter 10 and a plurality of photoelectric conversion elements 11. The solid-state image sensor filter 10 includes a green color filter 12G, a red color filter 12R, a blue color filter 12B, an infrared pass filter 12P, and microlenses 15G, 15R, 15B, and 15P. The infrared pass filter 12P has a structure in which the first pass element 12P1 and the second pass element 12P2 are laminated.

The green color filter 12G, the red color filter 12R, and the blue color filter 12B are a combination of a green photoelectric conversion element 11G, a red photoelectric conversion element 11R, a blue photoelectric conversion element 11B, and microlenses 15G, 15R, and 15B, respectively. Located in between. The infrared pass filter 12P is located between the infrared photoelectric conversion element 11P and the microlens 15P.

Among the photoelectric conversion elements 11, the green photoelectric conversion element 11G for visible light, the red photoelectric conversion element 11R, and the blue photoelectric conversion element 11B correspond to the first photoelectric conversion element in the present invention. Among the photoelectric conversion elements 11, the infrared photoelectric conversion element 11P corresponds to the second photoelectric conversion element in the present invention. 1 and 2 show the repeating unit of the photoelectric conversion element 11 in the solid-state image sensor, and shows the photoelectric conversion element 11G for green, the photoelectric conversion element 11R for red, the photoelectric conversion element 11B for blue, and the photoelectric conversion element 11P for infrared. Are arranged repeatedly. Therefore, the solid-state image sensor filter 10 has a unit including a green color filter 12G, a red color filter 12R, a blue color filter 12B, and an infrared pass filter 12P as one unit, and is horizontal and vertical on a two-dimensional plane. Multiple units are repeatedly arranged in the direction.

The red color filter 12R and the blue color filter 12B are arranged so as to be adjacent to each other on one side, and pixels of the same color as the second pass element 12P2 laminated on the upper layer of the infrared pass filter 12P are diagonally arranged. It is arranged so that it is located. In the example shown in FIG. 1, the first pass element 12P1 in the lower layer is a red filter element, the second pass element 12P2 in the upper layer is a blue filter element, and the blue color filter 12B is arranged diagonally. Shown. The first pass element 12P1 may be a blue filter element, the second pass element 12P2 may be a red filter element, and the red color filter 12R may be arranged diagonally.

The color filter for three colors includes a green color filter 12G for green pixels, a red color filter 12R for red pixels, and a blue color filter 12B for blue pixels. The green color filter 12G is located on the incident side of light with respect to the green photoelectric conversion element 11G. The red color filter 12R is located on the incident side of the light with respect to the red photoelectric conversion element 11R. The blue color filter 12B is located on the incident side of light with respect to the blue photoelectric conversion element 11B.

The green color filter 12G, the red color filter 12R, and the blue color filter 12B are formed by a photolithography method using a photosensitive coloring composition.

As the pigment contained in the photosensitive coloring composition, an organic or inorganic pigment can be used alone or in combination of two or more. As the pigment, a pigment having high color development and high heat resistance, particularly a pigment having high heat decomposition property is preferable, and an organic pigment is usually used. Pigments that can be used include phthalocyanine, azo, anthraquinone, quinacridone, dioxazine, anthraslon, indanthrone, perylene, thioindigo, isoindoline, quinophthalone, and diketopyrrolopyrrole. Examples include organic pigments such as system. Specific examples of organic pigments that can be used in the photosensitive coloring composition of the present invention are shown below by color index numbers.

In each color filter, examples of the blue dye used in the blue photosensitive coloring composition include CI Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 60. , 64, 81 and the like, with CI Pigment Blue 15: 6 being preferred. Examples of the purple pigment used for toning as needed include pigments such as CI Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, 50, and among them, CI Pigment. Violet 23 is preferred.

As yellow pigments, CI Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 138, 139, 147, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, Pigments such as 185, 187, 188, 193, 194, 198, 199, 213, 214 are mentioned, and CI Pigment Yellow 13, 150, 185 is preferable.

Examples of the red dye used in the red photosensitive coloring composition include CI Pigment Red 7, 9, 14, 41, 48: 1, 48: 2, 48: 3, 48: 4, instead of the blue dye and the like. 81: 1, 81: 2, 81: 3, 97, 122, 123, 146, 149, 168, 177, 178, 180, 184, 185, 187, 192, 200, 202, 208, 210, 215, 216, Red pigments such as 217, 220, 223, 224, 226, 227, 228, 240, 246, 254, 255, 264, 272, CI Pigment Orange 36, 43, 51, 55, 59, 61, 71, 73, and CI Pigment Yellow 1,2,3,4,5,6,10,12,13,14,15,16,17,18,24,31,32,34,35,35 for toning as needed 1, 36, 36: 1, 37, 37: 1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95 , 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 138, 139, 147. , 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181 , 182, 185, 187, 188, 193, 194, 198, 199, 213, 214 and the like.

Further, as the green pigment used in the green photosensitive coloring composition, instead of the blue pigment and the like, for example, a green pigment such as CI Pigment Green 7, 10, 376, 58 and the above yellow for toning as necessary. It is a composition obtained by using a pigment.

The photosensitive coloring composition of each color further contains a binder resin, a photopolymerization initiator, a polymerizable monomer, an organic solvent, a leveling agent and the like. Examples of the binder resin include acrylic resin, polyamide resin, polyimide resin, polyurethane resin, polyester resin, polyether resin, polyolefin resin, polycarbonate resin, polystyrene resin, and norbornene resin.

Examples of the photopolymerization initiator include an acetophenone-based photopolymerization initiator, a benzoin photopolymerization initiator, a benzophenone-based photopolymerization initiator, a thioxanson-based photopolymerization initiator, a triazine-based photopolymerization initiator, and an oxime ester-based photopolymerization initiator. The seeds may be used alone or in admixture of two or more.

Examples of the polymerizable monomer include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and tert-. Butyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, cyclohexyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl ( (Meta) acrylic acid esters such as meta) acrylate and tetrahydrofurfuryl (meth) acrylate; N-vinylpyrrolidone; styrene and its derivatives, styrenes such as α-methylstyrene; (meth) acrylamide, methylol (meth) acrylamide , Acrylates such as alkoxymethylol (meth) acrylamide, diacetone (meth) acrylamide; other vinyl compounds such as (meth) acrylonitrile, ethylene, propylene, butylene, vinyl chloride, vinyl acetate, and polymethylmethacrylate macromonomer, polystyrene macro Examples thereof include macromonomers such as monomers. These monomers may be used alone or in admixture of two or more.

Examples of the organic solvent include ethyl lactate, benzyl alcohol, 1,2,3-trichloropropane, 1,3-butanediol, 1,3-butylene glycol, 1,3-butylene glycol diacetate, 1,4-dioxane, and the like. 2-Heptanone, 2-Methyl-1,3-propanediol, 3,5,5-trimethyl-2-cyclohexene-1-one, 3,3,5-trimethylcyclohexanone, ethyl 3-ethoxypropionate, 3-methyl -1,3-butanol, 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-methylbutyl acetate, 3-methoxybutanol, 3-methoxybutyl acetate, 4-heptanone, m-xylene, m -Diethyl benzene, m-dichlorobenzene, N, N-dimethylacetamide, N, N-dimethylformamide, n-butyl alcohol, n-butylbenzene, n-propyl acetate, o-xylene, o-chlorotoluene, o-diethylbenzene, o-Dichlorobenzene, p-chlorotoluene, p-diethylbenzene, sec-butylbenzene, tert-butylbenzene, γ-butyrolactone, isobutyl alcohol, isophorone, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monoisopropyl ether, ethylene Glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monotersial butyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol monomethyl ether, ethylene glycol monomethyl Ether acetate, diisobutyl ketone, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether, cyclohexanol, cyclohexanol acetate, cyclohexanone, dipropylene glycol dimethyl ether , Dipropylene glycol methyl ether acetate, Dipropylene glycol monoethyl ether , Dipropylene glycol monobutyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monomethyl ether, diacetone alcohol, triacetin, tripropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, propylene glycol diacetate, propylene glycol phenyl ether, propylene glycol Monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, benzyl alcohol, methyl isobutyl ketone, methyl cyclo Examples thereof include hexanol, n-amyl acetate, n-butyl acetate, isoamyl acetate, isobutyl acetate, propyl acetate and dibasic acid ester. These can be used alone or in combination of two or more.

As the leveling agent, dimethylsiloxane having a polyether structure or a polyester structure in the main chain is preferable. Specific examples of the dimethylsiloxane having a polyether structure in the main chain include FZ-2122 manufactured by Toray Dow Corning Co., Ltd. and BYK-333 manufactured by Big Chemie Co., Ltd. Specific examples of the dimethylsiloxane having a polyester structure include BYK-310 and BYK-370 manufactured by Big Chemie. Dimethylsiloxane having a polyether structure and dimethylsiloxane having a polyester structure can also be used in combination. These can be used alone or in combination of two or more.

The infrared path filter 12P cuts visible light that can be detected by being incident on the infrared photoelectric conversion element 11P, and enhances the detection accuracy of infrared light by the infrared photoelectric conversion element 11P. The visible light that can be detected by the infrared photoelectric conversion element 11P is, for example, light having a wavelength of 400 nm or more and 700 nm or less. The infrared pass filter 12P is a layer located only on the infrared photoelectric conversion element 11P.

The infrared pass filter 12P can form an infrared pass filter 12P that cuts visible light and transmits infrared light by stacking a red filter element and a blue filter element. That is, as shown in FIG. 3, the red filter element has high light absorption around 400 nm to 550 nm and high light transmittance of 600 nm or more, and the blue filter element has high light absorption around 550 nm to 750 nm and 800 nm or more. Because of its high light transmittance, by superimposing the two, it is possible to obtain an infrared pass filter having high light absorption in the visible light region of 400 nm to 700 nm and high light transmittance of 850 nm or more in the near infrared region. ..

Further, it is desirable that the infrared pass filter 12P has the same or thicker thickness as the green color filter 12G, the red color filter 12R, and the blue color filter 12B included in the color filter. If the film thickness difference between the color filter and the infrared pass filter 12P is 0.1 μm or less, preferably 0.05 μm or less, there is no problem in forming the microlens. When the film thickness step is large, a flat layer may be appropriately formed on the color filter to flatten the step.

FIG. 4 is a graph showing an example of the transmission spectrum of the infrared pass filter. As shown in FIG. 4, the transmission spectrum of the infrared pass filter 12P shows, for example, a transmittance of 10% or less in the range of 400 nm or more and 700 nm or less. On the other hand, the infrared pass filter 12P has a peak in the vicinity of 850 nm and has a transmittance of 80% or more in the range exceeding 850 nm. In the present embodiment, an infrared pass filter 12P that cuts visible light and transmits infrared light is configured by stacking a red filter element and a blue filter element as the first pass element 12P1 and the second pass element 12P2. ing.

Near-infrared light having a wavelength of 850 nm is absorbed by water vapor contained in the atmosphere. That is, near-infrared light having a wavelength of 850 nm is light in which noise due to sunlight is removed by water vapor in the atmosphere. The infrared photoelectric conversion element 11P targets near-infrared light having a wavelength of 850 nm.

The microlens is composed of a green microlens 15G, a red microlens 15R, a blue microlens 15B, and an infrared microlens 15P. The green microlens 15G is located on the incident side of the light with respect to the green color filter 12G. The red microlens 15R is located on the incident side of the light with respect to the red color filter 12R. The blue microlens 15B is located on the incident side of the light with respect to the blue color filter 12B. The infrared microlens 15P is located on the incident side of light with respect to the infrared pass filter 12P.

Each microlens 15G, 15R, 15B, 15P includes an incident surface 15S which is an outer surface. Each microlens 15G, 15R, 15B, 15P has a refractive index difference with the outside air for collecting light entering the incident surface 15S toward each photoelectric conversion element 11G, 11R, 11B, 11P.

Next, a method for manufacturing a filter for a solid-state image sensor and a method for manufacturing a solid-state image sensor according to the present embodiment will be described with reference to FIGS. 5 to 8. The method for manufacturing a solid-state image sensor includes a step of forming each photoelectric conversion element 11 and a method for manufacturing a filter for a solid-state image sensor.

FIG. 5 is a diagram schematically showing a color filter manufacturing method in a conventional Bayer arrangement. When the color filter is manufactured in the Bayer arrangement, the green color filter 12G and the gap are arranged in a staggered pattern as shown in FIG. 5 (a), and one of the gaps is formed as shown in FIG. 5 (b). A red color filter 12R is formed in the portion, and a blue color filter 12B is formed in the remaining gap as shown in FIG. 5 (b). After that, a green microlens 15G, a red microlens 15R, a blue microlens 15B, and an infrared microlens 15P are formed on the color filter.

In a general Bayer arrangement, the green color filter 12G is included in two pixels, the red color filter 12R is included in one pixel, and the blue color filter 12B is included in one pixel. In such a Bayer arrangement, the red color filter 12R and the blue color filter 12B are both arranged so as to be adjacent to the green color filter 12G on all sides.

FIG. 6 is a diagram schematically showing a conventional method for manufacturing a filter for a solid-state image sensor. First, as shown in FIG. 6A, the green color filter 12G is formed in a grid pattern. Next, as shown in FIG. 6B, the red color filter 12R is formed in a striped manner along one direction of the gap between the green color filters 12G. Next, as shown in FIG. 6C, the blue color filter 12B is formed in a striped shape along the direction orthogonal to the red color filter 12R to fill the remaining voids. Finally, a green microlens 15G, a red microlens 15R, a blue microlens 15B, and an infrared microlens 15P are formed on the color filter.

However, when produced by such a manufacturing method, as shown in the cross-sectional view at the AA'position in FIG. 6D, the upper layer of the region where the red color filter 12R and the blue color filter 12B are laminated is formed. Since it is formed in a region where both sides are voids, undulations occur and the uniformity in the film thickness of the pixels is impaired.

FIG. 7 is a diagram schematically showing a method for manufacturing a filter for a solid-state image sensor according to the first embodiment. In this modified example as well, as the first step, as shown in FIG. 7A, the green color filter 12G is formed in a grid pattern. At this time, the green color filters 12G are separated from each other by a gap extending in the matrix direction. Next, as a second step, as shown in FIG. 7B, the red color filter 12R is formed so as to fill the red color filter 12R in a stripe shape along one direction of the gap between the green color filters 12G. At this time, the thicknesses of the green color filter 12G and the red color filter 12R are substantially the same.

Next, as a third step, as shown in FIG. 7 (c), the blue color filter 12B is formed on the remaining void portion and the region of the red color filter 12R sandwiched between the green color filter 12G. .. In the third step, the blue color filter 12B is formed on the remaining voids and the entire region of the red color filter 12R and the green color filter 12G, and then the blue color filter 12B is patterned using photolithography technology. .. Finally, as a fourth step, a green microlens 15G, a red microlens 15R, a blue microlens 15B, and an infrared microlens 15P are formed on the color filter.

FIG. 7 (d) schematically shows a cross section at the BB'position in FIG. 7 (c). A blue color filter 12B layer is formed on the red color filter 12R on the region of the red color filter 12R sandwiched between the green color filters 12G. In the region where the red color filter 12R and the blue color filter 12B overlap, the infrared pass filter 12P is configured, the lower blue color filter 12B becomes the first pass element 12P1, and the upper layer red color filter 12R Is the second pass element 12P2.

In the filter for the solid-state image sensor of the present embodiment, unlike the conventional Bayer arrangement shown in FIG. 5, one pixel of the green color filter 12G is replaced with the infrared pass filter 12P, and the red filter 12R and the blue filter are blue. Filter 12B is adjacent. By installing the infrared pass filter 12P at a position diagonal to the blue color filter 12B, there are no gaps on the four adjacent sides, and the area surrounded by the green color filter 12G and the red color filter 12R is the first. The 2-pass element 12P2 can be formed, and as a result, the film thickness uniformity of the second-pass element 12P2 is improved.

In the fourth step, a coating film containing a transparent resin is formed on the green color filter 12G, the red color filter 12R, the blue color filter 12B, and the infrared pass filter 12P. After that, the coating film is reflowed by patterning and heat treatment using a photolithography technique to form the respective microlenses 15G, 15R, 15B and 15P. The transparent resin is, for example, an acrylic resin, a polyamide resin, a polyimide resin, a polyurethane resin, a polyester resin, a polyether resin, a polyolefin resin, a polycarbonate resin, a polystyrene resin, or a norbornene resin.

The first to fourth steps described above use known photolithography techniques, but are not limited thereto. In particular, in the formation of the color filter in the first to third steps, a method of forming a non-photosensitive coloring composition obtained by removing the photopolymerization initiator and the polymerizable monomer from the photosensitive coloring composition by an etching method may be adopted. It may be combined with photolithography technology, often or in part. When a non-photosensitive coloring composition is used, the color density with respect to the film thickness can be increased, which is advantageous for thinning the film at the time of superimposition.

As described above, the first pass element 12P1 and the second pass element 12P2 constituting the infrared pass filter 12P are made of the same material as the blue pixel and the red pixel. Therefore, it is possible to suppress the occurrence of a difference depending on the constituent material between the processing conditions suitable for the color filter and the processing conditions suitable for the infrared pass filter 12P. Further, it is possible to suppress the occurrence of a difference depending on the constituent material between the usage environment suitable for the color filter and the usage environment suitable for the infrared pass filter.

The infrared light transmission function of the infrared pass filter 12P may change depending on the thickness of the infrared pass filter 12P. Since the step between the color filters 12G, 12R, 12B and the infrared pass filter 12P reduces the processing accuracy of the microlenses 15G, 15R, 15B, 15P, the filters for each color 12G, 12G, are used to ensure flatness. The difference between the thicknesses of 12R and 12B and the thickness of the infrared pass filter 12P is preferably 0.1 μm or less, and more preferably 0.05 μm or less.

(Second Embodiment)
FIG. 8 is a diagram schematically showing a method for manufacturing a filter for a solid-state image sensor according to the second embodiment. Also in this embodiment, as the first step, as shown in FIG. 8A, the green color filter 12G is formed in a grid pattern. Next, as a second step, as shown in FIG. 8B, the red color filter 12R is formed in a striped manner along one direction of the gap between the green color filters 12G. At this time, the thickness of the red color filter 12R is formed thinner than that of the green color filter 12G.

Next, as a third step, as shown in FIG. 8C, a blue color filter 12B is formed on the remaining void portion and the region of the red color filter 12R sandwiched between the green color filter 12G. .. In the third step, the blue color filter 12B is patterned using the photolithography technique as in the first embodiment. Alternatively, when it is desired to increase the color density with respect to the film thickness, a method of forming the non-photosensitive coloring composition by an etching method may be adopted. Finally, as a fourth step, a green microlens 15G, a red microlens 15R, a blue microlens 15B, and an infrared microlens 15P are formed on the color filter.

FIG. 8 (d) schematically shows a cross section at the CC'position in FIG. 8 (c). In this embodiment,
By making the film thickness of the first pass element 12P1 constituting the lower layer of the infrared pass filter 12P thinner than the film thickness of the adjacent green color filter 12G, the thickness of each color filter 12G, 12R, 12B and red The difference in thickness of the outer pass filter 12P can be reduced, and the flatness can be improved.

(Third Embodiment)
FIG. 9 is a diagram schematically showing the layer structure of the filter for a solid-state image sensor according to the third embodiment. In this embodiment, as shown in FIGS. 9A and 9B, a flattening layer 12F is provided on each of the color filters 12G, 12R, 12B and the infrared pass filter 12P. By providing the flattening layer 12F, the surface is flattened by filling the steps of the color filters 12G, 12R, 12B and the infrared pass filter 12P, and the base for forming the microlenses 15G, 15R, 15B, 15P. Can be flattened. Further, when forming the microlenses 15G, 15R, 15B, 15P, the coating film which is the material of the microlens 15 is used instead of the flattening layer 12F, and each color filter 12G, 12R, 12B and an infrared pass filter are used. The step formed by the difference in thickness of 12P may be flattened by filling the material of the microlens 15.

As described above, according to the above embodiment, the effects listed below can be obtained.
(1) The first pass element 12P1 and the second pass element 12P2, the red color filter 12R, and the blue color filter 12B are made of the same material. Therefore, it is possible to suppress the occurrence of a difference depending on the constituent material between the processing conditions suitable for the color filters 12R and 12B and the processing conditions suitable for the infrared pass filter 12P.

(2) Differences depending on the constituent materials are suppressed between the usage environment suitable for the color filters 12R and 12B and the usage environment suitable for the infrared pass filter 12P.

(3) Since the color filters 12R and 12B and the first pass element 12P1 and the second pass element 12P2 of the same color as the color filter are formed in the same process, it is for a solid-state image sensor equipped with an infrared sensor function. Manufacture is possible without reducing the productivity of the filter.

(4) Moreover, each color coating film for forming the color filters 12R and 12B and a coating film for forming the first pass element 12P1 and the second pass element 12P2 are formed as a single coating film. .. Therefore, the materials required for forming the color filters 12R and 12B and the infrared pass filter 12P can be used more effectively.

11 ... Photoelectric conversion element, 11G ... Green photoelectric conversion element, 11R ... Red photoelectric conversion element, 11B ... Blue photoelectric conversion element, 11P ... Infrared photoelectric conversion element, 12G ... Green color filter, 12R ... Red color Filter, 12B ... Blue color filter, 12P ... Infrared pass filter, 12P1 ... 1st pass element, 12P2 ... 2nd pass element, 12F ... Flattening layer, 15G ... Green microlens, 15R ... Red microlens, 15B ... Blue microlens, 15P ... Infrared microlens

Claims (6)

A color filter containing red pixels and blue pixels located on the incident side of light with respect to the first photoelectric conversion element, and
It is equipped with an infrared pass filter located on the incident side of light with respect to the second photoelectric conversion element.
The blue pixel and the red pixel are adjacent to each other on one side of each other.
In the infrared pass filter, two pass elements, red and blue, are laminated.
A filter for a solid-state image sensor, characterized in that the path elements laminated on the upper layer of the infrared pass filter have the same color as the diagonally located color filter. The red pixel, the blue pixel, the infrared path filter, and a unit including the green pixel are repeatedly arranged in the horizontal direction and the vertical direction on a two-dimensional plane as one unit. The filter for a solid-state image sensor according to claim 1. The filter for a solid-state image sensor according to claim 1 or 2, wherein the infrared pass filter has a thickness equal to or larger than that of the red pixel and the blue pixel. Photoelectric conversion element and
A solid-state image pickup device comprising the filter for the solid-state image pickup device according to any one of claims 1 to 3. A solid-state image sensor provided with a color filter containing red pixels and blue pixels located on the incident side of light with respect to the first photoelectric conversion element and an infrared path filter located on the incident side of light with respect to the second photoelectric conversion element. It is a manufacturing method of the filter for
The infrared pass filter is a laminate of two pass elements, red and blue.
The pass element has a film thickness equal to or less than that of the color filter of the same color as the pass element, and is composed of the same material as the color filter.
While forming the color filter of each color in a separate process,
A method for manufacturing a filter for a solid-state image sensor, which comprises forming the color filter of each color and the path element of the same color as the color filter in the same process. The process of forming a photoelectric conversion element and
A solid-state image sensor, which comprises a step of forming a filter for a solid-state image sensor on the incident side of light of the photoelectric conversion element by using the method for manufacturing a filter for a solid-state image sensor according to claim 5. Production method.