JP2024030916A - Infrared light cut filter, filter for solid-state image sensor, solid-state image sensor, and method for manufacturing filter for solid-state image sensor - Google Patents

Abstract

[Problem] To provide an infrared light cut filter, a filter for a solid-state image sensor, a solid-state image sensor, and a manufacturing method that enables patterning by photolithography and suppresses a decrease in absorbance of the infrared light cut filter and heat sag during manufacturing. SOLUTION: An infrared light cut filter 13 includes a cyanine dye, a copolymer, and a naphthoquinone diazide compound. The copolymer includes a first repeating unit derived from a monomer having a phenolic hydroxyl group and a second repeating unit represented by the following formula (1). The copolymer contains 15% to 70% by weight of the first repeating unit, and 30% to 85% by weight of the second repeating unit. JPEG2024030916000075.jpg59169 [Selection diagram] Figure 1

Description

The present invention relates to an infrared light cut filter, a filter for a solid-state image sensor, a solid-state image sensor, and a method for manufacturing a filter for a solid-state image sensor.

A solid-state image sensor includes an infrared light cut filter on a photoelectric conversion element. The infrared light absorption pigment of the infrared light cut filter absorbs infrared light, thereby cutting off infrared light that can be detected by each photoelectric conversion element from the photoelectric conversion element. This improves the detection accuracy of visible light in each photoelectric conversion element. The infrared light cut filter contains, for example, a cyanine dye that is an infrared light absorbing dye (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2007-219114

Incidentally, an infrared light cut filter included in a solid-state image sensor may require patterning depending on the laminated structure of the solid-state image sensor. For example, photolithography or dry etching can be used to pattern a thin film such as an infrared light cut filter. Of these, photolithography does not require processing under vacuum, and can therefore reduce the cost of manufacturing solid-state imaging devices compared to dry etching. Therefore, the infrared light cut filter is required to be patternable by photolithography, or in other words, to have developability by photolithography.

There are two types of photolithography transfer methods: negative type and positive type. In the negative type, the exposed portion of the object to be patterned forms the desired pattern. On the other hand, in the positive type, the unexposed portion of the patterning object forms the desired pattern. In patterning an infrared light cut filter, the infrared light cut filter that is the subject of exposure contains cyanine dye. When the cyanine dye contained in the infrared light cut filter is exposed to light, the cyanine dye may deteriorate. Therefore, from the viewpoint of suppressing deterioration of the cyanine dye, when patterning the infrared light cut filter by photolithography, it is preferable to select a positive type as the transfer method.

On the other hand, a positive resist containing a naphthoquinone diazide compound and a novolac type phenol resin is widely used as a resist for forming semiconductor devices. However, when an infrared light cut filter is formed using a positive resist containing a novolac-type phenolic resin, the cyanine dyes are associated with each other due to the difference in polarity between the novolak-type phenolic resin and the cyanine dye. An infrared light cut filter may be formed in this state. This reduces the ability of the cyanine dye contained in the infrared light cut filter to absorb infrared light. Therefore, there is a need for an infrared light cut filter that does not reduce the infrared light absorption ability of the cyanine dye and can be patterned in a positive type.

Further, when manufacturing an infrared light cut filter, after the infrared light cut filter is patterned, post-bake, which is a process in which the infrared light cut filter is heated, is performed. In patterning an infrared light cut filter, a hole pattern may be formed that penetrates the infrared light cut filter along the thickness direction of the infrared light cut filter. In this case, heat sag may occur in the hole pattern due to heating of the infrared light cut filter after patterning. Heat droop means that the corner formed by the surface of the infrared light cut filter and the side surface defining the hole pattern becomes rounded due to heating. As a result, unintended transmission of light through the hole pattern occurs, and unintended light is transmitted to the photoelectric conversion elements located around the hole pattern when viewed from a viewpoint facing the surface of the infrared light cut filter. may occur.

An infrared light cut filter for solving the above problems includes polymethine, a cation having a nitrogen-containing heterocycle located at each end of the polymethine, and a tris(pentafluoroethyl)trifluorophosphate anion. The copolymer includes a cyanine dye, a first repeating unit derived from a monomer having a phenolic hydroxyl group, and a second repeating unit represented by the following formula (1), and a naphthoquinonediazide compound. The copolymer includes 15% by weight or more and 70% by weight or less of the first repeating unit, and 30% by weight or more and 85% by weight or less of the second repeating unit.

However, in formula (1), A is a hydrogen atom, a halogen atom, or an alkyl group. X is an oxygen atom, NH, or NR5, and R5 is an alkyl group. R1, R2, R3, and R4 each independently represent a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, -OR6, -OCO-R7, -NHCO-R8, - NHCONHR9, -OCONH-R10, -COOR11, -CONHR12, -COR13, -CONR14R15, -CN, or -CHO. Alternatively, R1, R2, R3, and R4 may form a cyclic structure by combining two of them. R6 to R15 are each independently an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group.

A method for producing a filter for a solid-state imaging device to solve the above problems includes polymethine, a cation having a nitrogen-containing heterocycle located at each end of the polymethine, and a tris(pentafluoroethyl)trifluorophosphate anion. and a copolymer containing a first repeating unit derived from a monomer having a phenolic hydroxyl group and a second repeating unit represented by the above formula (1), and an infrared ray containing a naphthoquinonediazide compound. The method includes forming a light cut filter and patterning the infrared light cut filter by photolithography. The copolymer includes 15% by weight or more and 70% by weight or less of the first repeating unit, and 30% by weight or more and 85% by weight or less of the second repeating unit.

According to the method for producing an infrared light cut filter and a filter for a solid-state image sensor, the copolymer contains the second repeating unit and also contains a naphthoquinone diazide compound, so that the infrared light cut filter can be produced. In this case, patterning using positive photolithography is possible. In addition, since the copolymer contains a first repeating unit of 15% to 70% by weight and a second repeating unit of 30% to 85% by weight, a decrease in the absorbance of the infrared light cut filter is suppressed. , and it is possible to suppress heat sag caused by heating.

In the infrared light cut filter, the weight of the naphthoquinonediazide compound may be 5% by weight or more and 40% by weight or less based on the weight of the copolymer. According to this infrared light cut filter, since the amount of the naphthoquinone diazide compound is 5% by weight or more, the developability of the unexposed area of the infrared light cut filter decreases, and the developability of the exposed area decreases. improves. This increases the precision in the shape of the infrared light cut filter. Further, since the amount of the naphthoquinonediazide compound is 40% by weight or less, deterioration of the cyanine dye is suppressed, and therefore a decrease in the absorbance of the infrared light cut filter is suppressed.

In the above infrared light cut filter, in the formula (1), A is a hydrogen atom or a methyl group, X is an oxygen atom, NH, or NR5, and R5 is an alkyl group. , R1, R2, R3, and R4 are each independently a hydrogen atom, a halogen atom, a methyl group, a substituted alkyl group substituted with a halogen atom, or -OR6, and R6 is a methyl group; good.

In the infrared light cut filter, the copolymer may have an average molecular weight of 3,000 or more and 300,000 or less. According to this infrared light cut filter, since the average molecular weight is 3000 or more, association of the cyanine dye contained in the infrared light cut filter is suppressed by the copolymer. This suppresses a decrease in absorbance in the infrared region of the infrared light cut filter. Further, since the copolymer has a molecular weight of 300,000 or less, the solubility of the copolymer in a developing solution is unlikely to decrease, so that the infrared light cut filter has developability. This suppresses peeling of the infrared light cut filter during development of the infrared light cut filter. Therefore, patterning of the infrared light cut filter is easy.

A filter for a solid-state image sensor for solving the above problems includes the above-mentioned infrared light cut filter, a barrier layer that covers the infrared light cut filter and suppresses transmission of an oxidation source that oxidizes the infrared light cut filter. Equipped with

A solid-state image sensor for solving the above problems includes a photoelectric conversion element and the solid-state image sensor filter.

According to the present invention, while enabling patterning by positive photolithography, it is possible to suppress a decrease in the absorbance of an infrared light cut filter, and to suppress heat sag caused by heating during manufacturing of the infrared light cut filter. is possible.

FIG. 1 is an exploded perspective view showing the structure of a solid-state image sensor according to an embodiment. It is a table showing the blending ratio of monomers in each production example.

[Solid-state image sensor]
A solid-state image sensor will be explained with reference to FIG. FIG. 1 is a schematic configuration diagram separately showing each layer in a part of a solid-state image sensor.

As shown in FIG. 1, the solid-state image sensor 10 includes a solid-state image sensor filter 10F and a plurality of photoelectric conversion elements 11. The plurality of photoelectric conversion elements 11 include a red photoelectric conversion element 11R, a green photoelectric conversion element 11G, a blue photoelectric conversion element 11B, and an infrared photoelectric conversion element 11P. The photoelectric conversion elements 11R, 11G, and 11B for each color measure the intensity of visible light having a specific wavelength associated with the photoelectric conversion element 11R, 11G, and 11B. Each infrared light photoelectric conversion element 11P measures the intensity of infrared light.

The solid-state image sensor 10 includes a plurality of red photoelectric conversion elements 11R, a plurality of green photoelectric conversion elements 11G, a plurality of blue photoelectric conversion elements 11B, and a plurality of infrared photoelectric conversion elements 11P. Note that in FIG. 1, for convenience of illustration, a repeating unit of the photoelectric conversion element 11 in the solid-state image sensor 10 is shown.

The solid-state image sensor filter 10F includes a plurality of visible light filters, an infrared light pass filter 12P, an infrared light cut filter 13, a barrier layer 14, a plurality of visible light microlenses, and an infrared light microlens 15P. Equipped with

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

The infrared light pass filter 12P is located on the light incident side with respect to the infrared light photoelectric conversion element 11P. The infrared light pass filter 12P cuts visible light that can be detected by the infrared photoelectric conversion element 11P. That is, the infrared light pass filter 12P absorbs visible light that can be detected by the infrared light photoelectric conversion element 11P, so that the visible light incident on the infrared light pass filter 12P is transmitted to the infrared light photoelectric conversion element. Prevent reaching 11P. This increases the accuracy of infrared light detection by the infrared light photoelectric conversion element 11P. The infrared light that can be detected by the infrared photoelectric conversion element 11P is, for example, near-infrared light.

The infrared light cut filter 13 is located on the light incident side with respect to the color filters 12R, 12G, and 12B. The infrared light cut filter 13 includes a through hole 13H. The infrared light pass filter 12P is located within the area defined by the through hole 13H when viewed from a viewpoint facing the plane in which the infrared light cut filter 13 extends. On the other hand, when viewed from a viewpoint facing the plane in which the infrared light cut filter 13 extends, the infrared light cut filter 13 is located above the red filter 12R, the green filter 12G, and the blue filter 12B.

The infrared light cut filter 13 contains cyanine dye, which is an infrared light absorbing dye. Cyanine dyes have a maximum value of absorption of infrared light at any wavelength included in near-infrared light. Therefore, according to the infrared light cut filter 13, it is possible to reliably absorb the near infrared light that passes through the infrared light cut filter 13. Thereby, near-infrared light that can be detected by the photoelectric conversion elements 11 for each color is sufficiently cut off by the infrared light cut filter 13. That is, the infrared light cut filter 13 absorbs infrared light that can be detected by the photoelectric conversion elements 11R, 11G, and 11B for each color, so that the infrared light that has entered the infrared light cut filter 13 can be detected by the photoelectric conversion elements 11R, 11G, and 11B for each color. The photoelectric conversion elements 11R, 11G, and 11B are prevented from reaching the photoelectric conversion elements 11R, 11G, and 11B. The infrared light cut filter 13 can have a thickness of, for example, 300 nm or more and 3 μm or less.

The barrier layer 14 suppresses transmission of the oxidation source through the infrared light cut filter 13. Oxidation sources include, for example, oxygen and water. It is preferable that the barrier layer 14 has an oxygen permeability of, for example, 5.0 cc/m ² /day/atm or less. The oxygen permeability is based on Annex A of JIS K7126-2:2006, and is a value at 23° C. and 50% relative humidity. Since the oxygen transmittance is set to 5.0 cc/m ² /day/atm or less, the barrier layer 14 prevents the oxidation source from reaching the infrared light cut filter 13, so the infrared light cut filter 13 is prevented from being oxidized. Becomes less susceptible to oxidation depending on the source. Therefore, the light resistance of the infrared light cut filter 13 can be improved.

The material forming the barrier layer 14 is an inorganic compound. The material forming the barrier layer 14 is preferably a silicon compound. The silicon compound may be, for example, at least one selected from the group consisting of silicon nitride, silicon oxide, and silicon oxynitride.

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

Each of the microlenses 15R, 15G, 15B, and 15P includes an entrance surface 15S that is an outer surface. Each of the microlenses 15R, 15G, 15B, and 15P has a refractive index difference between the microlenses 15R, 15G, 15B, and 15P and the outside air to collect the light that enters the incident surface 15S toward each of the photoelectric conversion elements 11R, 11G, 11B, and 11P. Each microlens 15R, 15G, 15B, 15P contains transparent resin.

[Infrared light cut filter]
The infrared light cut filter 13 will be explained in more detail below.
The infrared light cut filter 13 contains a cyanine dye, a copolymer, and a naphthoquinone diazide compound. Cyanine dyes include cations and anions. The cation has polymethine and a nitrogen-containing heterocycle located at each end of polymethine. The anion is tris(pentafluoroethyl)trifluorophosphate anion.

The copolymer includes a first repeating unit derived from a monomer having a phenolic hydroxyl group and a second repeating unit represented by the following formula (1). The copolymer contains 15% by weight or more and 70% by weight or less of first repeating units, and contains 30% by weight or more and 85% by weight or less of second repeating units.

According to the infrared light cut filter of the present disclosure, since the copolymer contains the second repeating unit and also contains the naphthoquinonediazide compound, patterning by positive photolithography is possible in the production of the infrared light cut filter. It is possible. In addition, since the copolymer contains a first repeating unit of 15% to 70% by weight and a second repeating unit of 30% to 85% by weight, a decrease in the absorbance of the infrared light cut filter is suppressed. , and it is possible to suppress heat sag caused by heating.

In the infrared light cut filter of the present disclosure, since the copolymer has the second repeating unit, the coating film can be patterned by photolithography. Specifically, in the aromatic ring included in the second repeating unit, a carboxyl group is bonded to the carbon at the ortho position to the carbon to which the acryloyl group is bonded. This allows the naphthoquinone diazide to interact with the carboxyl groups, and as a result, the mixture of the copolymer and the naphthoquinone diazide compound can have insolubility in alkaline developers. In addition, when the naphthoquinone diazide compound is changed into indene carboxylic acid by exposure to light, the indene carboxylic acid does not interact with the carboxyl group of the copolymer, so the copolymer and the naphthoquinone diazide compound are It is possible for a mixture of the following to have solubility in an alkaline developer.

The copolymer includes a first repeating unit derived from a monomer having a phenolic hydroxyl group. In the first repeating unit, the phenolic hydroxyl group is capable of interacting with the naphthoquinone diazide. Furthermore, the phenolic hydroxyl group and naphthoquinone diazide can be condensed by post-baking the coating film that is a precursor of the infrared light cut filter. Therefore, according to the copolymer containing the first repeating unit, it is possible to suppress heat sagging during post-baking.

The copolymer also includes a second repeating unit. Since the second repeating unit has a large cohesive force, the interaction between molecules is large, and this also makes it possible to suppress heat sag during post-baking. Therefore, according to the copolymer, it is possible to suppress heat sagging during post-baking by both the first repeating unit and the second repeating unit.

On the other hand, the polymer solution used to form the infrared light cut filter may contain the radical polymerization initiator used during monomer polymerization. As a result, an infrared light cut filter produced using a polymer solution may also contain a radical polymerization initiator. The radical polymerization initiator contained in the infrared light cut filter may generate radicals by being activated when the infrared light cut filter is heated. According to the infrared light cut filter of the present disclosure, the first repeating unit included in the copolymer can capture radicals. Therefore, according to an infrared light cut filter containing a copolymer, even if the infrared light cut filter contains a radical polymerization initiator, decomposition and modification caused by radicals in the cyanine dye can be suppressed. This prevents the infrared light cut filter from deteriorating due to heating.

Furthermore, in the aromatic ring that the second repeating unit has, as described above, a carboxyl group is bonded to the carbon at the ortho position to the carbon to which the acryloyl group is bonded. Therefore, the copolymer is easily compatible with the cyanine dye, and as a result, it is possible to suppress the association of the cyanine dye. Thereby, in the infrared light cut filter, it is possible to suppress a decrease in the infrared light absorption ability.

The cyanine dye may have a structure represented by the following formula (2).

In the above formula (2), X is one methine or polymethine. The hydrogen atom bonded to the carbon atom contained in methine may be substituted with a halogen atom or an organic group. Polymethine may have a cyclic structure containing carbon forming polymethine. The cyclic structure can include three consecutive carbons in the plurality of carbons forming polymethine. When polymethine has a cyclic structure, the number of carbon atoms in polymethine may be 5 or more. Each nitrogen atom is included in a five-membered or six-membered heterocycle. Heterocycles may be fused. Y ⁻ is an anion.

Further, the cyanine dye may have a structure represented by the following formula (3).

In the above formula (3), n is an integer of 1 or more. n indicates the number of repeating units contained in the polymethine chain. R11 and R12 are hydrogen atoms or organic groups. R13 and R14 are hydrogen atoms or organic groups. R13 and R14 are preferably linear alkyl groups having 1 or more carbon atoms or branched alkyl groups. Each nitrogen atom is included in a five-membered or six-membered heterocycle. Heterocycles may be fused.

In addition, in formula (2), when polymethine includes a cyclic structure, the cyclic structure has at least one unsaturated bond such as an ethylenic double bond, and the unsaturated bond may be a cyclic structure that resonates electronically as part of the polymethine chain. Such cyclic structures may be, for example, cyclopentene rings, cyclopentadiene rings, cyclohexene rings, cyclohexadiene rings, cycloheptene rings, cyclooctene rings, cyclooctadiene rings, and benzene rings. Any of these cyclic structures may have a substituent.

Further, in formula (3), the compound where n is 1 is cyanine, the compound where n is 2 is carbocyanine, and the compound where n is 3 is dicarbocyanine. In formula (3), the compound where n is 4 is tricarbocyanine.

The organic group of R11 and R12 may be, for example, an alkyl group, an aryl group, an aralkyl group, and an alkenyl group. Alkyl groups include, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group. , nonyl group, decyl group, etc. The aryl group may be, for example, a phenyl group, tolyl group, xylyl group, naphthyl group, and the like. The aralkyl group may be, for example, a benzyl group, a phenylethyl group, a phenylpropyl group, etc. The alkenyl group may be, for example, a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group, an octenyl group, and the like.

Note that at least a portion of the hydrogen atoms possessed by each organic group may be substituted with a halogen atom or a cyano group. Halogen atoms may be fluorine, bromine, chlorine, and the like. The organic group after substitution may be, for example, a chloromethyl group, a chloropropyl group, a bromoethyl group, a trifluoropropyl group, a cyanoethyl group, or the like.

R13 or R14 is, for example, a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group. group, nonyl group, decyl group, etc.

The heterocycle containing each nitrogen atom may be, for example, pyrrole, imidazole, thiazole, and pyridine.
The cation contained in such a cyanine dye may have a structure represented by the following formula (4) and the following formula (5), for example.

なお、シアニン色素が含むカチオンは、例えば、下記式（６）から式（４５）に示される構造を有してもよい。すなわち、シアニン色素が含む各窒素原子は、以下に示される環状構造中に含まれてもよい。

In addition, the cation contained in the cyanine dye may have a structure shown in the following formulas (6) to (45), for example. That is, each nitrogen atom included in the cyanine dye may be included in the cyclic structure shown below.

Cyanine dyes have a maximum absorbance of infrared light at any wavelength within the range of 700 nm or more and 1100 nm or less. Therefore, according to the infrared light cut filter 13, it is possible to reliably absorb the near infrared light that passes through the infrared light cut filter 13. Thereby, near-infrared light that can be detected by the photoelectric conversion elements 11 for each color is sufficiently cut off by the infrared light cut filter 13.

The infrared light cut filter 13 may contain only one type of cyanine dye, or may contain two or more types of cyanine dye.
Note that the absorbance Aλ at the wavelength λ is calculated by the following formula.

Aλ=-log ₁₀ (%T/100)
The transmittance T is expressed by the ratio (TL/IL) of the intensity (TL) of the transmitted light to the intensity (IL) of the incident light when the infrared light is transmitted through the infrared light cut filter 13 having a cyanine dye. be done. In the infrared light cut filter 13, the intensity of transmitted light when the intensity of incident light is 1 is the transmittance T, and the value obtained by multiplying the transmittance T by 100 is the transmittance percentage %T.

Tris(pentafluoroethyl)trifluorophosphate anion ([(C ₂ F ₅ ) ₃ PF ₃ ] ⁻ ) has a structure represented by the following formula (46).

In the manufacturing process of the solid-state image sensor 10, the infrared light cut filter 13 is heated to about 200°C. When the above-mentioned cyanine dye is heated to about 200° C., the structure of the cyanine dye changes, which may change the transmittance of the cyanine dye to infrared light.

In this respect, since the FAP anion has a molecular weight and a molecular structure that allows it to be located near the polymethine chain in the cyanine dye, the polymethine chain of the cyanine dye is prevented from being cut by heating the cyanine dye. Therefore, changes in the infrared light transmittance of the cyanine dye due to heating of the cyanine dye are suppressed, and as a result, changes in the infrared light transmittance of the infrared light cut filter 13 are suppressed. suppressed.

As mentioned above, the infrared light cut filter 13 contains a copolymer. The copolymer includes a first repeating unit and a second repeating unit. The first repeating unit is derived from a monomer having a phenolic hydroxyl group. The second repeating unit is derived from a monomer represented by the following formula (1). The copolymer contains a first repeating unit of 15% to 70% by weight and a second repeating unit of 30% to 85% by weight.

Monomers having a phenolic hydroxyl group include, for example, 4-hydroxyphenyl (meth)acrylate, 4-hydroxyphenyl (meth)acrylamide, 3-(tert-butyl)-4-hydroxyphenyl (meth)acrylate, 4-(tert- butyl)-2-hydroxyphenyl (meth)acrylate, 4-hydroxyphenylmaleimide, 3-hydroxyphenylmaleimide, p-hydroxystyrene, α-methyl-p-hydroxystyrene, and the like. A copolymer produced using such a monomer having a phenolic hydroxyl group contains a phenolic hydroxyl group in the side chain.

In formula (1), A is a hydrogen atom, a halogen atom, or an alkyl group. The halogen atom is preferably a chlorine atom or a bromine atom. The alkyl group may be an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms.

In the above formula (1), R1, R2, R3, and R4 are each independently a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, -OR6, -OCO-R7 , -NHCO-R8, -NHCONHR9, -OCONH-R10, -COOR11, -COONHR12, -COOR13, -CONR14R15, -CN, or -CHO.

The alkyl group may be an alkyl group having 1 to 20 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms. The aryl group may be an aryl group having 6 to 20 carbon atoms, and preferably has 6 to 10 carbon atoms. The aryl group may be a phenyl group or a naphthyl group.

Substituents or substituent atoms contained in the substituted alkyl group and the substituted aryl group include, for example, an aryl group, an alkoxy group having 1 to 10 carbon atoms, a halogen atom, an alkoxycarbonyl group, an acyloxy group, a formyl group, an ether group, etc. It may be. In addition to these, the substituent included in the substituted aryl group may be an alkyl group having 1 or more and 10 or less carbon atoms.

R1, R2, R3, and R4 may form a cyclic structure by combining two of them. The cyclic structure formed by bonding two of R1 to R4 is preferably a 5- to 7-membered ring. The cyclic structure may be an aliphatic ring or an aryl ring having 4 or more and 14 or less carbon atoms. Aliphatic or aryl rings may be, for example, cyclopentane, cyclohexane, benzene, naphthalene, and the like. The cyclic structure may be a heterocycle containing one or more and four or less heteroatoms. The heterocycle may be, for example, pyridyl, furyl, pyrrole, indole, and the like.

R5 may be an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms.
R6 to R15 are an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group. The alkyl group may be an alkyl group having 1 to 20 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms. The aryl group may be an aryl group having 6 or more and 20 or less carbon atoms, and is preferably an aryl group having 6 or more and 10 or less carbon atoms. The aryl group may be a phenyl group or a naphthyl group.

The substituents or substituent atoms contained in the substituted alkyl group and the substituted aryl group include, for example, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogen atom, and a halogen atom having 1 to 10 carbon atoms. It may be an alkoxycarbonyl group having 2 to 10 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, a formyl group, or the like. In addition to these, the substituent included in the substituted aryl group may be an alkyl group having 1 or more and 10 or less carbon atoms.

In formula (1), A is particularly preferably a hydrogen atom or a methyl group. Preferably, X is an oxygen atom, NH, or NR5. It is particularly preferred that R5 is a methyl group. R1 to R4 are an alkyl group substituted with an alkoxy group, the total number of carbon atoms being 1 to 15, a halogen atom, an alkyl group having 1 to 8 carbon atoms, a halogen atom, Preferably, they are an aryl group, -OR6 group, -OCOR7 group, and -OCONHR9 group. It is particularly preferable that R1 to R4 are a hydrogen atom, a halogen atom, a methyl group, an alkyl group substituted with a halogen atom, or a methoxy group. Note that the methoxy group is the name of a substituent when R6 in -OR6 is a methyl group.

Further, the halogen atom is preferably a chlorine atom. The substituted alkyl group is preferably an alkyl group substituted with a halogen atom. Note that R6, R7, and R9 are each independently an alkyl group having 1 to 8 carbon atoms, an aryl group, a halogen atom, an aryl group, or an alkyl group substituted with an alkoxy group, and all carbon atoms are A substituted alkyl group with a number of 1 to 15, or an aryl group substituted with a halogen atom, an alkyl group, or an alkoxy group, and a substituted aryl group with a total number of carbon atoms of 6 to 15. is preferred.

Furthermore, as described above, two of R1 to R4 may be bonded together to form a cyclic structure. When one of the two forming the cyclic structure is an aryl group to which a carboxyl group is bonded, the cyclic structure formed by the condensed ring is naphthalene, tetralin, indene, indanone, tetralone, benzofuran, or indole. It may be.

The repeating unit represented by the above formula (1) can have, for example, the structure shown below. In addition, it is preferable that a repeating unit is a structure shown by Formula (47) to Formula (52) among the structures shown below.

Note that the copolymer may include a third repeating unit other than the first repeating unit and the second repeating unit. The monomer from which the third repeating unit is derived may be, for example, a styrene monomer, a (meth)acrylic monomer, a vinyl ester monomer, a vinyl ether monomer, a halogen element-containing vinyl monomer, a diene monomer, or the like.

Styrenic monomers include, for example, styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, p-methoxystyrene, p-hydroxystyrene, p-acetoxystyrene, vinyltoluene, ethylstyrene, phenylstyrene, and It may be benzylstyrene or the like.

(Meth)acrylic monomers include, for example, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, and phenoxypolypropylene glycol (meth)acrylate. ) acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl hydrogen phthalate, 2-(meth)acryloyloxypropyl Hydrogen phthalate, ethoxylated ortho-phenylphenol (meth)acrylate, o-phenylphenoxyethyl (meth)acrylate, 3-phenoxybenzyl (meth)acrylate, 4-hydroxyphenyl (meth)acrylate, 2-naphthol (meth)acrylate, 4-biphenyl (meth)acrylate, 9-anthrylmethyl (meth)acrylate, 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl (meth)acrylate, phenol ethylene oxide (EO) Modified acrylate, nonylphenol EO modified acrylate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl hexahydrophthalate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-t-cyclohexyl ( meth)acrylate, isobornyl(meth)acrylate, dicyclopentanyl(meth)acrylate, dicyclopentenyl(meth)acrylate, adamantyl(meth)acrylate, norbornyl(meth)acrylate, tricyclodecanyl(meth)acrylate, dicyclo Pentadienyl (meth)acrylate, tetracyclododecyl (meth)acrylate, glycidyl (meth)acrylate, 2-methylglycidyl (meth)acrylate, 2-ethylglycidyl (meth)acrylate, 2-oxiranylethyl (meth)acrylate , 2-glycidyloxyethyl (meth)acrylate, 3-glycidyloxypropyl (meth)acrylate, glycidyloxyphenyl (meth)acrylate, oxetanyl (meth)acrylate, 3-methyl-3-oxetanyl (meth)acrylate, 3-ethyl -3-oxetanyl (meth)acrylate, (3-methyl-3-oxetanyl)methyl (meth)acrylate, (3-ethyl-3-oxetanyl)methyl (meth)acrylate, 2-(3-methyl-3-oxetanyl) Ethyl (meth)acrylate, 2-(3-ethyl-3-oxetanyl)ethyl (meth)acrylate, 2-[(3-methyl-3-oxetanyl)methyloxy]ethyl (meth)acrylate, 2-[(3- ethyl-3-oxetanyl)methyloxy]ethyl (meth)acrylate, 3-[(3-methyl-3-oxetanyl)methyloxy]propyl (meth)acrylate, 3-[(3-ethyl-3-oxetanyl)methyloxy ] Propyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and the like.

The vinyl ester monomer may be, for example, vinyl acetate. The vinyl ether monomer may be, for example, vinyl methyl ether. The halogen element-containing vinyl monomer may be, for example, vinyl chloride. The diene monomer may be, for example, butadiene and isobutylene.

Further, the copolymer may contain a monomer for adjusting the polarity of the copolymer. Monomers for adjusting polarity add acid groups or hydroxyl groups to the copolymer. Such monomers may be, for example, acrylic acid, methacrylic acid, maleic anhydride, maleic acid half ester, 2-hydroxyethyl acrylate, and 4-hydroxyphenyl (meth)acrylate.

Moreover, the copolymer may have any structure of a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer. If the structure of the copolymer is a random copolymer, the manufacturing process and preparation with cyanine dyes are easy. Therefore, random copolymers are preferred over other copolymers.

The polymerization method for obtaining the copolymer may be, for example, radical polymerization, cationic polymerization, anionic polymerization, living radical polymerization, living cationic polymerization, living anionic polymerization, or the like. Radical polymerization is preferably selected as the polymerization method for obtaining the copolymer because it is easy to produce industrially. Radical polymerization may be a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, or the like. It is preferable to use a solution polymerization method for radical polymerization. By using the solution polymerization method, it is easy to control the molecular weight of the copolymer. Furthermore, a solution containing the copolymer after polymerization of the monomer can be used in the form of a solution to manufacture a filter for a solid-state imaging device.

In radical polymerization, after diluting the monomers mentioned above with a polymerization solvent, a radical polymerization initiator may be added to polymerize the monomers.
The polymerization solvent may be, for example, an ester solvent, an alcohol ether solvent, a ketone solvent, an aromatic solvent, an amide solvent, or an alcohol solvent. The ester solvent may be, for example, methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl lactate, ethyl lactate, propylene glycol monomethyl ether acetate, and the like. Examples of alcohol ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, 3-methoxy-1-butanol, and 3-methoxy-3-methyl-1- It may be butanol or the like. The ketone solvent may be, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Aromatic solvents may include, for example, benzene, toluene, and xylene. The amide solvent may be, for example, formamide and dimethylformamide. The alcoholic solvent may be, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, s-butanol, t-butanol, diacetone alcohol, and 2-methyl-2-butanol. . Among these, ketone solvents and ester solvents are preferable because they can be used for manufacturing filters for solid-state imaging devices. In addition, in the polymerization solvent mentioned above, one type may be used individually, and two or more types may be mixed and used.

In radical polymerization, the amount of the polymerization solvent used is not particularly limited, but when the total monomer is set to 100 parts by weight, the amount of the polymerization solvent used is preferably 1 part by weight or more and 1000 parts by weight or less, and 100 parts by weight or less. More preferably, it is at least 500 parts by weight.

Radical polymerization initiators may be, for example, peroxides and azo compounds. Peroxides can be, for example, benzoyl peroxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, di-t-butyl peroxide, and the like. Azo compounds include, for example, azobisisobutyronitrile, azobisamidinopropane salt, azobiscyanovaleric acid (salt), and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl) propionamide] and the like.

The amount of the radical polymerization initiator used is preferably 0.0001 parts by weight or more and 20 parts by weight or less, and 0.001 parts by weight or more and 15 parts by weight or less, when the total monomer is set to 100 parts by weight. More preferably, the amount is 0.005 parts by weight or more and 10 parts by weight or less. The radical polymerization initiator may be added to the monomer and the polymerization solvent before starting the polymerization, or may be added dropwise into the polymerization reaction system. It is preferable to drop the radical polymerization initiator into the polymerization reaction system with respect to the monomer and the polymerization solvent since heat generation due to polymerization can be suppressed.

The reaction temperature for radical polymerization is appropriately selected depending on the type of radical polymerization initiator and polymerization solvent. The reaction temperature is preferably 60° C. or higher and 110° C. or lower from the viewpoint of ease of production and reaction controllability.

The glass transition temperature of the copolymer is preferably 75°C or higher, more preferably 100°C or higher. If the glass transition temperature is 75° C. or higher, it is possible to increase the reliability of suppressing changes in the transmittance of infrared light when the infrared light cut filter 13 is heated in the infrared light cut filter. .

The molecular weight of the copolymer is preferably 3,000 or more and 300,000 or less, more preferably 5,000 or more and 100,000 or less. By having the molecular weight of the copolymer within this range, it is possible to maintain the developability of the infrared light cut filter 13 while maintaining the spectral characteristics of the cyanine dye contained in the infrared light cut filter 13. .

When the copolymer has a molecular weight exceeding 300,000, the solubility of the copolymer in a developer decreases. As a result, when the infrared light cut filter 13 containing the copolymer is developed, the infrared light cut filter 13 is difficult to dissolve in the developing solution. The cut filter 13 is easily peeled off from the support. Therefore, if the molecular weight of the copolymer exceeds 300,000, it is not easy to pattern the infrared light cut filter 13. On the other hand, if the molecular weight of the copolymer is 300,000 or less, the solubility of the copolymer in the developer is unlikely to decrease, so the infrared light cut filter 13 is Peeling is suppressed. Therefore, patterning of the infrared light cut filter 13 is easy.

In addition, when the molecular weight of the copolymer is less than 3000, the cyanine dye can be easily moved due to the small molecular weight of the copolymer, so that the cyanine dye contained in the infrared light cut filter 13 may not be associated with the copolymer. It is difficult to obtain the effect of suppressing Therefore, the absorbance in the infrared region of the infrared light cut filter 13 tends to decrease. On the other hand, when the molecular weight of the copolymer is 3000 or more, the copolymer suppresses association of the cyanine dye contained in the infrared light cut filter 13. This suppresses a decrease in absorbance in the infrared region of the infrared light cut filter 13.

Note that the average molecular weight of the copolymer is the weight average molecular weight. The weight average molecular weight of the copolymer can be measured, for example, by gel permeation chromatography. For example, in a radical polymerization reaction, the molecular weight of a copolymer can be controlled by changing the concentrations of monomers and radical polymerization initiators in a solution.

The polymer solution obtained by producing the copolymer contains the copolymer and the monomer. The monomers are monomers that were not used for producing the copolymer among the monomers prepared for producing the copolymer. In the polymer solution, the weight of the copolymer is a first weight W1, and the weight of the monomer is a second weight W2.

The percentage ({W2/(W1+W2)}×100) of the second weight W2 with respect to the sum of the first weight W1 and the second weight W2 (W1+W2) is preferably 20% or less. That is, it is preferable that the remaining monomers be 20% or less of the monomers prepared for producing the copolymer. When the residual monomer is 20% or less, the increase in transmittance in the infrared light cut filter is suppressed compared to when the residual monomer is more than 20%.

Note that the percentage of the second weight W2 with respect to the total sum of the first weight W1 and the second weight W2 is more preferably 10% or less, and even more preferably 3% or less. The first weight W1 and the second weight W2 can be determined based on the analysis results of the copolymer. The copolymer analysis method may be, for example, gas chromatography quantitative spectroscopy (GC-MS), nuclear magnetic resonance spectroscopy (NMR), and infrared spectroscopy (IR).

For example, when determining the first weight W1 and the second weight using NMR analysis results, first, a spectrum of the polymer solution is obtained by NMR analysis. Next, in the obtained spectrum, the peak of the copolymer and the peak of the monomer are identified. Then, the area ratio of each peak is calculated. The area ratio at the peak of the copolymer is the first weight W1, and the area ratio at the peak of the monomer is the second weight W2.

The method of changing the percentage of the second weight W2 with respect to the sum of the first weight W1 and the second weight W2 may be, for example, a method of changing the polymerization time, a method of changing the polymerization temperature, etc. Further, the method of changing the percentage of the second weight W2 with respect to the sum of the first weight W1 and the second weight W2 may be a method of changing the concentration of the monomer and the radical polymerization initiator at the time of starting the polymerization reaction. Further, the method of changing the percentage of the second weight W2 with respect to the total sum of the first weight W1 and the second weight W2 may be a method of changing the purification conditions after the polymerization reaction. Among these methods, the method of changing the polymerization time is preferable because the control accuracy of changing the proportion of the second weight W2 is high.

When the radical polymerization initiator used during polymerization of the copolymer is an organic peroxide having an aromatic ring in the side chain, the amount of copolymer contained in the infrared light cut filter is set to 100 parts by weight. Preferably, the infrared light cut filter contains less than 0.35 parts by weight of organic peroxide. When the infrared light cut filter contains less than 0.35 parts by weight of organic peroxide, deterioration of the spectral characteristics of the infrared light cut filter in the visible light region and the infrared light region can be suppressed.

The naphthoquinonediazide compound may be a naphthoquinonediazide-based photosensitizer. Naphthoquinone diazide photosensitizers are also used as photosensitizers for positive photoresists. The naphthoquinone diazide photosensitizer may be, for example, an ester compound of naphthoquinone diazide sulfonic acid chloride and a phenolic compound.

The naphthoquinonediazide sulfonic acid chloride may be, for example, 1,2-naphthoquinone-2-diazide-5-sulfonic acid chloride, 1,2-naphthoquinone-2-diazide-4-sulfonic acid chloride.

Examples of the phenolic compound include trihydroxybenzophenone, tetrahydroxybenzophenone, pentahydroxybenzophenone, hexahydroxybenzophenone, (polyhydroxyphenyl)alkane, 2,3,4-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,3,4,3'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3,4,2'-tetra Hydroxy-4'-methylbenzophenone, 2,3,4,4'-tetrahydroxy-3'-methoxybenzophenone, 2,3,4,2',6'-pentahydroxybenzophenone, 2,4,6,3' , 4',5'-hexahydroxybenzophenone, 3,4,5,3',4',5'-hexahydroxybenzophenone, bis(2,4-dihydroxyphenyl)methane, bis(p-hydroxyphenyl)methane, Tris(p-hydroxyphenyl)methane, 1,1,1-tris(p-hydroxyphenyl)ethane, bis(2,3,4-trihydroxyphenyl)methane, 2,2-bis(2,3,4- trihydroxyphenyl)propane, 1,1,3-tris(2,5-dimethyl-4-hydroxyphenyl)-3-phenylpropane, 4,4'-[1-{4-(1-[4-hydroxyphenyl ]-1-methylethyl)phenyl}ethylidene]bisphenol, bis(2,5-dimethyl-4-hydroxyphenyl)-2-hydroxyphenylmethane, 3,3,3',3'-tetramethyl-1,1' -spirobiindene-5,6,7,5',6',7'-hexanol, 2,2,4-trimethyl-7,2',4'-trihydroxyflavan, 2-methyl-2-(2 , 4-dihydroxyphenyl)-4-(4-hydroxyphenyl)-7-hydroxychroman, 1-[1-{3-(1-[4-hydroxyphenyl]-1-methylethyl)-4,6-dihydroxy phenyl}-1-methylethyl]-3-[1-{3-(1-[4-hydroxyphenyl]-1-methylethyl)-4,6-dihydroxyphenyl}-1-methylethyl]benzene, 4, It may be 6-bis{1-(4-hydroxyphenyl)-1-methylethyl}-1,3-dihydroxybenzene.

The infrared light cut filter 13 may contain only one kind of naphthoquinonediazide compound, or may contain two or more kinds of naphthoquinone diazide compounds. The weight of the naphthoquinonediazide compound may be 5% or more by weight based on the weight of the copolymer. That is, when the total amount of the copolymer (Wcp) is set to 100% by weight, the weight of the naphthoquinone diazide compound (Wnd) may be 5% by weight or more based on the total amount of the copolymer. In other words, the weight of the naphthoquinonediazide compound may satisfy the following formula:

100 (Wnd/Wcp)≧5 (weight%)
When the amount of the naphthoquinonediazide compound is 5% by weight or more, in the infrared light cut filter 13, the developability of unexposed areas is reduced and the developability of exposed areas is improved. This improves the precision in the shape of the infrared light cut filter 13.

The weight of the naphthoquinonediazide compound may be up to 40% by weight based on the weight of the copolymer. That is, when the total amount (Wcp) of the copolymer is set to 100% by weight, the weight (Wnd) of the naphthoquinonediazide compound may be 40% by weight or less based on the total amount of the copolymer. In other words, the weight of the naphthoquinonediazide compound may satisfy the following formula:

100 (Wnd/Wcp)≦40 (weight%)
When the amount of the naphthoquinone diazide compound is 40% by weight or less, decomposition of the cyanine dye due to the diazo group of the naphthoquinone diazide is suppressed, and therefore a decrease in the absorbance of the infrared light cut filter 13 is suppressed.

The infrared light cut filter 13 may contain a surfactant, a storage stabilizer, an adhesion aid, a heat resistance improver, and the like. The infrared light cut filter 13 may contain only one kind of these, or may contain two or more kinds.

[Method for manufacturing a filter for solid-state imaging device]
The method for manufacturing the solid-state imaging device filter 10F includes forming the infrared light cut filter 13 and patterning the infrared light cut filter 13 by photolithography. In forming the infrared light cut filter 13, the infrared light cut filter 13 containing a cyanine dye, a copolymer, and a naphthoquinone diazide compound is formed. The copolymer contains a first repeating unit of 15% to 70% by weight and a second repeating unit of 30% to 85% by weight. Hereinafter, the method for manufacturing the solid-state image sensor filter 10F will be described in more detail.

The filters for each color 12R, 12G, 12B and the infrared light pass filter 12P are formed by forming a coating film containing a colored photosensitive resin and patterning the coating film using a photolithography method. For example, a coating film containing a red photosensitive resin is formed by applying a coating liquid containing a red photosensitive resin and drying the coating film formed by the coating. The red filter 12R is formed by exposing a coating film containing a red photosensitive resin to light corresponding to the area of the red filter 12R and developing it. Note that the green filter 12G, the blue filter 12B, and the infrared light pass filter 12P are also formed by the same method as the red filter 12R.

For the pigments contained in the coloring compositions of the red filter 12R, the green filter 12G, and the blue filter 12B, organic or inorganic pigments can be used alone or in combination of two or more types. The pigment is preferably a pigment with high color development and high heat resistance, particularly a pigment with high heat decomposition resistance, and is preferably an organic pigment. Examples of organic pigments include phthalocyanine, azo, anthraquinone, quinacridone, dioxazine, anthanthrone, indanthrone, perylene, thioindigo, isoindoline, quinophthalone, and diketopyrrolopyrrole. It's good.

Moreover, a black pigment or a black dye can be used as the coloring component contained in the infrared light pass filter 12P. The black pigment may be a single pigment having a black color, or a mixture of two or more pigments having a black color. The black dye may be, for example, an azo dye, an anthraquinone dye, an azine dye, a quinoline dye, a perinone dye, a perylene dye, a methine dye, or the like.

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.
When forming the infrared light cut filter 13, a coating solution containing the above-mentioned cyanine dye, copolymer, naphthoquinone diazide compound, and organic solvent is applied to each color filter 12R, 12G, 12B and the infrared light path. Apply on the filter 12P. In this way, an infrared light cut filter 13 is formed. Next, the infrared light cut filter 13 is exposed using a positive photomask. Thereafter, the exposed infrared light cut filter 13 is developed using an alkaline developer, and then the developed infrared light cut filter 13 is washed with water and dried. The dried infrared light cut filter 13 is heated to harden it. As a result, the infrared light cut filter 13 is patterned.

A tetraammonium hydroxide (TMAH) aqueous solution can be used as the alkaline developer. The concentration of the TMAH aqueous solution is not particularly limited as long as it is a concentration that allows development of the infrared light cut filter 13. The method of bringing the infrared light cut filter 13 into contact with the developer may be a dipping method, a spray method, a spin method, or the like.

The barrier layer 14 is formed by a vapor phase deposition method such as a sputtering method, a CVD method, or an ion plating method, or a liquid phase deposition method such as a coating method. The barrier layer 14 made of silicon oxide is formed, for example, by sputtering using a target made of silicon oxide on the substrate on which the infrared light cut filter 13 is formed. The barrier layer 14 made of silicon oxide is formed, for example, on a substrate on which the infrared light cut filter 13 is formed, through CVD film formation using silane and oxygen. The barrier layer 14 made of silicon oxide is formed, for example, by applying a coating solution containing polysilazane, modifying it, and drying the coating film. The layer structure of the barrier layer 14 may be a single layer structure made of a single compound, a laminated structure of layers made of a single compound, or a laminated structure of layers made of mutually different compounds. It's okay.

Each of the microlenses 15R, 15G, 15B, and 15P is formed by forming a coating film containing a transparent resin, patterning the coating film using a photolithography method, and reflowing by heat treatment. Examples of the transparent resin include acrylic resin, polyamide resin, polyimide resin, polyurethane resin, polyester resin, polyether resin, polyolefin resin, polycarbonate resin, polystyrene resin, and norbornene resin. be.

[Manufacturing example]
A manufacturing example of a copolymer for manufacturing an infrared light cut filter will be described with reference to FIG. 2. In addition, when the copolymer is a copolymer produced using two or more types of monomers, the weight ratio of the repeating units derived from each monomer in the produced copolymer is the same as that of the copolymer. Equal to the weight ratio of each monomer at the time of production.

In addition, in FIG. 2, compound A-1 is a monomer for obtaining the unit structure shown in formula (47), and compound A-2 is a monomer for obtaining the unit structure shown in formula (48). Compound A-3 is a monomer for obtaining the unit structure shown by formula (49), and compound A-4 is a monomer for obtaining the unit structure shown by formula (50). Compound B-1 is 4-hydroxyphenyl (meth)acrylate and compound B-2 is 4-hydroxyphenyl (meth)acrylamide. Further, DCPMA is dicyclopentanyl acrylate, PhMA is phenyl methacrylate, and MAA is methacrylic acid.

[Manufacture example 1]
150 parts by weight of propylene glycol monomethyl ether acetate (PGMAc) was prepared as a polymerization solvent, and 50 parts by weight of Compound A-1 and 50 parts by weight of DCPMA were prepared as monomers. Additionally, 1.5 parts by weight of benzoyl peroxide (BPO) was prepared as a radical polymerization initiator. These were placed in a reaction vessel equipped with a stirring device and a reflux tube, and while nitrogen gas was introduced into the reaction vessel and heated to 80° C., the mixture was stirred and refluxed for 8 hours. Thereby, a polymer solution containing a copolymer produced from Compound A-1 and DCPMA was obtained. The weight average molecular weight of the copolymer was 15,000.

[Manufacture example 2]
50 parts by weight of Compound A-1, 10 parts by weight of Compound B-1, and 40 parts by weight of DCPMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-1, and DCPMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 18,000.

[Manufacture example 3]
50 parts by weight of Compound A-1, 15 parts by weight of Compound B-1, and 35 parts by weight of DCPMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-1, and DCPMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 11,000.

[Manufacture example 4]
50 parts by weight of Compound A-1, 20 parts by weight of Compound B-1, and 30 parts by weight of DCPMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-1, and DCPMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the polymer was 15,000.

[Manufacture example 5]
90 parts by weight of Compound A-1 and 10 parts by weight of Compound B-1 were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1 and Compound B-1 was obtained in the same manner as in Production Example 1. The weight average molecular weight of the copolymer was 13,000.

[Manufacture example 6]
70 parts by weight of Compound A-1, 15 parts by weight of Compound B-1, and 15 parts by weight of DCPMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-1, and DCPMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 13,000.

[Manufacture example 7]
70 parts by weight of Compound A-1, 20 parts by weight of Compound B-1, and 10 parts by weight of DCPMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-1, and DCPMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 18,000.

[Manufacture example 8]
50 parts by weight of Compound A-1, 20 parts by weight of Compound B-1, and 30 parts by weight of PhMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-1, and PhMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 15,000.

[Manufacture example 9]
30 parts by weight of Compound A-1 and 70 parts by weight of Compound B-1 were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1 and Compound B-1 was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 11,000.

[Manufacture example 10]
20 parts by weight of Compound A-1 and 80 parts by weight of Compound B-1 were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1 and Compound B-1 was obtained in the same manner as in Production Example 1. The weight average molecular weight of the copolymer was 13,000.

[Manufacture example 11]
60 parts by weight of Compound A-1, 35 parts by weight of Compound B-1, and 5 parts by weight of MAA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-1, and MAA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 15,000.

[Manufacture example 12]
50 parts by weight of Compound A-2 and 50 parts by weight of DCPMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-2 and DCPMA was obtained in the same manner as in Production Example 1. The weight average molecular weight of the copolymer was 10,000.

[Manufacture example 13]
50 parts by weight of Compound A-2, 20 parts by weight of Compound B-1, and 30 parts by weight of PhMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-2, Compound B-1, and PhMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 15,000.

[Manufacture example 14]
60 parts by weight of Compound A-2, 37 parts by weight of Compound B-1, and 3 parts by weight of MAA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-2, Compound B-1, and MAA was obtained in the same manner as in Production Example 1. The weight average molecular weight of the copolymer was 13,000.

[Manufacture example 15]
50 parts by weight of Compound A-3, 20 parts by weight of Compound B-1, and 30 parts by weight of PhMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-3, Compound B-1, and PhMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 18,000.

[Manufacture example 16]
50 parts by weight of Compound A-4, 20 parts by weight of Compound B-1, and 30 parts by weight of PhMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-4, Compound B-1, and PhMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 13,000.

[Manufacture example 17]
50 parts by weight of Compound A-1, 10 parts by weight of Compound B-2, and 40 parts by weight of DCPMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-2, and DCPMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 15,000.

[Manufacture example 18]
50 parts by weight of Compound A-1, 15 parts by weight of Compound B-2, and 35 parts by weight of DCPMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-2, and DCPMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 10,000.

[Manufacture example 19]
50 parts by weight of Compound A-1, 20 parts by weight of Compound B-2, and 30 parts by weight of DCPMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-2, and DCPMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 15,000.

[Production example 20]
50 parts by weight of Compound A-2, 20 parts by weight of Compound B-2, and 30 parts by weight of PhMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-2, and PhMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 18,000.

[Manufacture example 21]
50 parts by weight of Compound A-3, 20 parts by weight of Compound B-2, and 30 parts by weight of PhMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-2, and PhMA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 18,000.

[Production example 22]
50 parts by weight of Compound A-4, 20 parts by weight of Compound B-2, and 30 parts by weight of PhMA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound A-1, Compound B-2, and PhMA was obtained in the same manner as in Production Example 1. The weight average molecular weight of the copolymer was 11,000.

[Manufacture example 23]
15 parts by weight of Compound B-1, 70 parts by weight of DCPMA, and 15 parts by weight of MAA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from Compound B-1, DCPMA, and MAA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 15,000.

[Production example 24]
85 parts by weight of DCPMA and 15 parts by weight of MAA were prepared as monomers. Other than that, a polymer solution containing a copolymer produced from DCPMA and MAA was obtained by the same method as in Production Example 1. The weight average molecular weight of the copolymer was 13,000.

[Example 1]
In each production example, a 25% polymer solution was obtained by diluting the polymer solution such that the weight of copolymer relative to the weight of the polymer solution was 25%. By using the 25% polymer solutions of Production Examples 1 to 24, the infrared light cut filters of Examples 1-1 to 1-16 and Comparative Examples 1-1 to 1-8 were produced. Obtained.

[Spectral characteristics]
A coating solution containing 0.4 g of cyanine dye, 12.5 g of 25% polymer solution, 0.625 g of naphthoquinone diazide compound, and 10 g of propylene glycol monomethyl ether acetate was prepared. At this time, a dye represented by the above formula (4) was used as the cyanine dye, and 24 types of polymer solutions each containing the copolymer obtained in Production Example 1 to Production Example 24 described above were used. . In addition, as naphthoquinonediazide compounds, 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol and 1,2-naphthoquinone-2-diazide- An ester with 5-sulfonic acid chloride was used.

A coating film was formed by applying the coating liquid onto a transparent substrate, and then the coating film was dried by heating it at 90° C. for 2 minutes. The coating was then heated at 200°C for 10 minutes. As a result, for each Example and each Comparative Example, an infrared light cut filter having a thickness of 1.5 μm and for evaluating spectral characteristics was obtained.

Using a spectrophotometer (manufactured by Hitachi High-Tech Science Co., Ltd., U-4100), the transmittance of the infrared light cut filter of each Example and each Comparative Example for light having wavelengths from 350 nm to 1150 nm was measured. As a result, a transmittance spectrum was obtained for each infrared light cut filter.

[Rectangularity]
A coating liquid similar to that used in evaluating spectral characteristics was prepared. Next, a coating solution containing the copolymer of each production example was applied to the silicon wafer coated with the flattening layer using a spin coater, thereby forming a coating film. At this time, the rotation speed of the spin coater was set to 1000 rpm. The coating film was then prebaked by heating the silicon wafer on which the coating film was formed using a hot plate. At this time, the heating conditions using the hot plate were set to 90° C. and 2 minutes.

Thereafter, the prebaked coating film was exposed to light using an exposure machine (FPA-5510iZ, manufactured by Canon Inc.). At this time, an exposure mask having a square hole pattern of 2.0 μm×2.0 μm was used, and the exposure amount was set to 5000 J/m ² . Tetramethylammonium hydroxide (TMAH) was adjusted with pure water so that its concentration was 1.0% by weight, thereby obtaining an alkaline developer. The exposed coating film was developed using an alkaline developer, and then the coating film was washed with water and dried, thereby obtaining a coating film having a hole pattern of 2.0 μm square. Next, the coated film was post-baked by heating the silicon wafer having the developed coated film using a hot plate. At this time, the heating conditions using the hot plate were set to 200° C. and 10 minutes. As a result, for each example and each comparative example, an infrared light cut filter having a thickness of 1.5 μm and a hole pattern, and an infrared light cut filter for evaluating rectangularity, was used. Obtained.

A cross section for observation was prepared by cutting the infrared light cut filter along the thickness direction of the silicon wafer. At this time, the infrared light cut filter was cut so that the observation cross section included a plurality of hole patterns. The cross section for observation was observed using a scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation). At this time, the observation magnification of the scanning electron microscope was set to 30,000 times. Regarding the hole pattern, the angle formed between the surface of the infrared light cut filter and the side surface defining the hole pattern was measured.

[Evaluation results]
The evaluation results of spectral characteristics and rectangularity were as shown in Table 1 below.

As shown in Table 1, the transmittance at 950 nm was measured from Examples 1-2, 1-5, 1-8, 1-10, 1-11, and 1-13. It was found to be 5% in Examples 1-16. Furthermore, it was observed that the transmittance at 950 nm was 7% in Example 1-9, and 8% in Example 1-1, Example 1-3, Example 1-4, and Example 1-12. It was done. In addition, the transmittance at 950 nm was 9% in Examples 1-6 and 1-7, and 10% in Comparative Examples 1-1 to 1-3, Comparative Examples 1-5, and Comparative Examples 1-6. %. Further, it was observed that the transmittance at 950 nm was 15% in Comparative Example 1-4, 25% in Comparative Example 1-7, and 35% in Comparative Example 1-8.

In this way, the infrared light cut filter of each example has a transmittance of 9% or less at 950 nm, that is, it has a preferable infrared light absorption ability when applied as a filter for a solid-state image sensor. This was recognized. On the other hand, in the infrared light cut filters of Comparative Examples 1-1 to 1-6, the transmittance at 950 nm is 15% or less, which is a preferable infrared light cut filter when applied as a filter for a solid-state image sensor. It was confirmed that it has the ability to absorb external light. On the other hand, in the infrared light cut filters of Comparative Examples 1-7 and 1-8, the transmittance at 950 nm is 25% or more, that is, the transmittance is not suitable for filters for solid-state image sensors. was recognized as having the following.

Further, it was observed that the rectangularity was 75° in Example 1-6 and 80° in Example 1-1 and Example 1-12. In addition, the rectangularity was 85° in Examples 1-2, 1-5, 1-8, 1-10, 1-11, 1-13 to 1-16. It was recognized that Further, the rectangularity was found to be 88° in Examples 1-3, 1-4, 1-7, and 1-9.

On the other hand, the rectangularity was found to be 60° in Comparative Examples 1-7. In addition, in the infrared light cut filters of Comparative Examples 1-1 to 1-3, Comparative Example 1-5, Comparative Example 1-6, and Comparative Example 1-8, the surface of the infrared light cut filter and the hole pattern were It was observed that heat sag caused by post-baking occurred at the corner formed by the side surface. Note that heat droop means a state in which the corners are rounded. Further, in Comparative Examples 1-4, it was observed that no hole pattern was formed, that is, patterning by photolithography was not possible.

From these results, we believe that the copolymer contained in the infrared light cut filter can achieve both high infrared light absorption ability and suppression of heat sag in the hole pattern by satisfying the following conditions. I can say that.

(Condition 1) Contains the first repeating unit in an amount of 15% by weight or more and 70% by weight or less.
(Condition 2) Contains the second repeating unit in an amount of 30% by weight or more and 85% by weight or less.
[Example 2]
[Content of naphthoquinone diazide compound]
By using the copolymer of Production Example 4, seven types of infrared light cut filters described below were obtained.

A coating solution containing 0.4 g of cyanine dye, 12.5 g of 25% polymer solution, naphthoquinone diazide compound, and 10 g of propylene glycol monomethyl ether acetate was prepared. At this time, a dye represented by the above formula (4) was used as the cyanine dye. In addition, as naphthoquinone diazide, 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol and 1,2-naphthoquinone-2-diazide-5 -Used an ester with sulfonic acid chloride. A coating film was formed by applying the coating liquid onto a transparent substrate, and then the coating film was heated at 90° C. for 2 minutes. As a result, the coating film was dried, and as a result, an infrared light cut filter having a thickness of 1.5 μm was obtained.

Seven types of infrared light cut filters were obtained by changing the amount of the naphthoquinone diazide compound to seven different amounts as shown in Table 2 below. Note that the proportion of the naphthoquinone diazide compound contained in the infrared light cut filter of each example was calculated using the following formula.

Content (weight%) = 100 (Wnd/Wcp)
In the above formula, Wnd is the weight of the naphthoquinonediazide compound, and Wcp is the weight of the copolymer.

As shown in Table 2, in Example 2-1, the amount of the naphthoquinone diazide compound was set to 0.095 g, so that when the copolymer was 100% by weight, the proportion of the naphthoquinone diazide compound was 3% by weight. It was set to %. In Test Example 2-2, the amount of the naphthoquinone diazide compound was set to 0.155 g, thereby setting the proportion of the naphthoquinone diazide compound to 5% by weight when the copolymer was 100% by weight.

In Test Example 2-3, the amount of the naphthoquinonediazide compound was set to 0.315 g, and thereby, when the copolymer was 100% by weight, the proportion of the naphthoquinonediazide compound was set to 10% by mass. In Test Example 2-4, the amount of the naphthoquinonediazide compound was set to 0.625 g, and thereby, when the copolymer was 100% by weight, the proportion of the naphthoquinonediazide compound was set to 20% by weight.

In Test Example 2-5, the amount of the naphthoquinonediazide compound was set to 0.950 g, and thereby, when the copolymer was 100% by weight, the proportion of the naphthoquinonediazide compound was set to 30% by weight. In Test Example 2-6, the amount of the naphthoquinonediazide compound was set to 1.250 g, thereby setting the proportion of the naphthoquinonediazide compound to 40% by weight when the copolymer was 100% by weight. In Test Example 2-7, the amount of the naphthoquinonediazide compound was set to 1.400 g, and thereby the proportion of the naphthoquinonediazide compound was set to 45% by weight when the copolymer was 100% by weight.

[Evaluation results]
The transmittance and rectangularity of the infrared light cut filters of each example were evaluated. Note that the same methods as those described in Example 1 were used to evaluate transmittance and rectangularity. The results of evaluating the spectral characteristics and rectangularity were as shown in Table 3 below.

As shown in Table 3, the transmittance at 950 nm was found to be 5% in Examples 2-1 to 2-4 and 8% in Example 2-5. Further, it was observed that the transmittance at 950 nm was 9% in Example 2-6 and 15% in Example 2-7. As described above, it was confirmed that all of the examples had an infrared light absorbing ability suitable as an infrared light cut filter. In addition, from the viewpoint of increasing infrared light absorption ability, the proportion of the naphthoquinonediazide compound is preferably 3% by weight or more and 40% by weight or less, preferably 3% by weight or more and 30% by weight or less, and 3% by weight. It can be said that it is more preferable that the content is 20% by weight or less.

The rectangularity was found to be 75° in Example 2-1, 80° in Example 2-2, 83° in Example 2-3, and 85° in Example 2-4. It was done. Further, the rectangularity was found to be 88° in Examples 2-5 to 2-7. In this way, it was confirmed that heat sag was suppressed in all Examples. In addition, from the viewpoint of improving rectangularity, the proportion of the naphthoquinone diazide compound is preferably 5% by weight or more and 45% by weight or less, more preferably 10% by weight or more and 45% by weight or less, and 20% by weight or more and 45% by weight. % or less, and most preferably 30% by weight or more and 45% by weight or less.

From these results, from the viewpoint of both increasing infrared light absorption ability and increasing rectangularity, the proportion of the naphthoquinone diazide compound is preferably 5% by weight or more and 40% by weight or less, and 10% by weight. It is more preferable that the content is 30% by weight or less, and even more preferably 20% or more and 30% by weight or less.

As explained above, according to an embodiment of an infrared light cut filter, a solid-state image sensor filter, a solid-state image sensor, and a method for manufacturing a solid-state image sensor filter, the following effects can be obtained. .

(1) Since the infrared light cut filter 13 contains the naphthoquinone diazide compound and the copolymer contains the second repeating unit, patterning using positive photolithography is possible in the production of the infrared light cut filter. It is.

(2) Since the copolymer contains 15% to 70% by weight of the first repeating unit and 30% to 85% by weight of the second repeating unit, the absorbance of the infrared light cut filter is reduced. In addition, it is possible to suppress heat sag caused by heating.

(3) When the amount of the naphthoquinone diazide compound is 5% by weight or more, in the infrared light cut filter 13, the developability of unexposed areas is reduced and the developability of exposed areas is improved. This improves the precision in the shape of the infrared light cut filter 13. Further, since the amount of the naphthoquinone diazide compound is 40% by weight or less, deterioration of the cyanine dye is suppressed, and therefore a decrease in the absorbance of the infrared light cut filter 13 is suppressed.

(4) If the molecular weight of the copolymer is 300,000 or less, the solubility of the acrylic polymer in the developer is unlikely to decrease, so that the infrared light cut filter 13 can be easily peeled off during development. It can be suppressed. Therefore, patterning of the infrared light cut filter 13 is easy.

(5) When the molecular weight of the copolymer is 3000 or more, association of the cyanine dye contained in the infrared light cut filter 13 is suppressed by the acrylic polymer. This suppresses a decrease in absorbance in the infrared region of the infrared light cut filter 13.

Note that the embodiment described above can be modified and implemented as follows.
[Barrier layer]
- The barrier layer 14 may be arranged not only between the infrared light cut filter 13 and the microlenses 15R, 15G, 15B, and 15P, but also on the outer surface of each of the microlenses 15R, 15G, 15B, and 15P.

- The solid-state image sensor 10 may include an anchor layer between the barrier layer 14 and the layer below the barrier layer 14. In this case, the adhesion between the barrier layer 14 and the layer below the barrier layer 14 is enhanced by the anchor layer. Further, the solid-state imaging device 10 may include an anchor layer between the barrier layer 14 and the upper layer of the barrier layer 14. In this case, the anchor layer can enhance the adhesion between the barrier layer and the upper layer of the barrier layer. The material forming the anchor layer is, for example, a polyfunctional acrylic resin or a silane coupling agent.

- The layer structure of the barrier layer 14 may be a single layer structure made of a single compound, a laminated structure of layers made of a single compound, or a laminated structure of layers made of mutually different compounds. good.

- The barrier layer 14 may function as a flattening layer that fills the level difference formed between the surface of the infrared light cut filter 13 and the surface of the infrared light pass filter 12P.
- The solid-state image sensor filter 10F does not need to include the barrier layer 14. Even in this case, it is possible to obtain effects similar to (1) and (2) above.

[others]
- The thickness of each color filter 12R, 12G, 12B may be the same size as the infrared light pass filter 12P, or may be a different size. The thickness of each color filter 12R, 12G, 12B may be, for example, 0.5 μm or more and 5 μm or less.

- The color filter may be a three-color filter including a cyan filter, a yellow filter, and a magenta filter. Further, the color filter may be a four-color filter including a cyan filter, a yellow filter, a magenta filter, and a black filter. Further, the color filter may be a four-color filter including a transparent filter, a yellow filter, a red filter, and a black filter.

- The color filters 12R, 12G, and 12B may have the same thickness as the infrared light pass filter 12P, or may have different thicknesses from each other. The thickness of each color filter 12R, 12G, 12B may be, for example, 0.5 μm or more and 5 μm or less.

- The materials forming the infrared light cut filter 13 are additives such as light stabilizers, antioxidants, heat stabilizers, and antistatic agents, and the infrared light cut filter 13 absorbs infrared light. It is possible to include additives to provide other functions.

- In the solid-state image sensor 10, the oxygen transmittance in the stacked structure located on the side of the entrance surface 15S with respect to the infrared light cut filter 13 may be 5.0 cc/m ² /day/atm or less. For example, the laminated structure may include other functional layers such as a flattening layer and an adhesion layer, and together with each microlens, the oxygen permeability thereof may be 5.0 cc/m ² /day/atm or less.

- The solid-state image sensor 10 may include a bandpass filter on the light incident surface side of the plurality of microlenses. The bandpass filter is a filter that transmits only light having specific wavelengths of visible light and near-infrared light, and has a similar function to the infrared light cut filter 13. That is, unnecessary infrared light that can be detected by the photoelectric conversion elements 11R, 11G, and 11B for each color can be cut by the bandpass filter. This improves the detection accuracy of visible light by the photoelectric conversion elements 11R, 11G, and 11B for each color, and the detection of near-infrared light having a wavelength in the 850 nm or 940 nm band, which is the detection target of the infrared photoelectric conversion element 11P. Accuracy can be increased.

10... Solid-state image sensor 10F... Filter for solid-state image sensor 11... Photoelectric conversion element 12B... Filter for blue color 12G... Filter for green color 12P... Infrared light pass filter 12R... Filter for red color 13... Infrared light cut filter 13H... Through hole 14...Barrier layer 15B...Microlens for blue color 15G...Microlens for green color 15P...Microlens for infrared light 15R...Microlens for red color

Claims (7)

Polymethine, and a cyanine dye located at each end of the polymethine and containing a cation having a nitrogen-containing heterocycle and a tris(pentafluoroethyl)trifluorophosphate anion;
A copolymer containing a first repeating unit derived from a monomer having a phenolic hydroxyl group and a second repeating unit represented by the following formula (1),
comprising a naphthoquinone diazide compound,
The copolymer is
15% by weight or more and 70% by weight or less of the first repeating unit;
An infrared light cut filter comprising 30% by weight or more and 85% by weight or less of the second repeating unit.
However, in formula (1), A is a hydrogen atom, a halogen atom, or an alkyl group. X is an oxygen atom, NH, or NR5, and R5 is an alkyl group. R1, R2, R3, and R4 each independently represent a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, -OR6, -OCO-R7, -NHCO-R8, - NHCONHR9, -OCONH-R10, -COOR11, -CONHR12, -COR13, -CONR14R15, -CN, or -CHO. Alternatively, R1, R2, R3, and R4 may form a cyclic structure by combining two of them. R6 to R15 are each independently an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group. The infrared light cut filter according to claim 1, wherein the weight of the naphthoquinone diazide compound is 5% by weight or more and 40% by weight or less based on the weight of the copolymer. In the above formula (1),
A is a hydrogen atom or a methyl group,
X is an oxygen atom, NH, or NR5, R5 is an alkyl group,
R1, R2, R3, and R4 are each independently a hydrogen atom, a halogen atom, a methyl group, a substituted alkyl group substituted with a halogen atom, or -OR6, and R6 is a methyl group. 2. The infrared light cut filter according to 1 or 2. The average molecular weight of the copolymer is 3000 or more and 300,000 or less,
The infrared light cut filter according to claim 1 or 2. The infrared light cut filter according to claim 1 or 2,
A filter for a solid-state imaging device, comprising: a barrier layer that covers the infrared light cut filter and suppresses transmission of an oxidation source that oxidizes the infrared light cut filter. A photoelectric conversion element,
A solid-state image sensor, comprising: the filter for a solid-state image sensor according to claim 5. Polymethine, a cyanine dye containing a cation having a nitrogen-containing heterocycle and a tris(pentafluoroethyl) trifluorophosphate anion located at each end of the polymethine, and a first compound derived from a monomer having a phenolic hydroxyl group. Forming an infrared light cut filter containing a copolymer containing a repeating unit and a second repeating unit represented by the following formula (1), and a naphthoquinone diazide compound;
patterning the infrared light cut filter by photolithography,
The copolymer is
15% by weight or more and 70% by weight or less of the first repeating unit;
30% by weight or more and 85% by weight or less of the second repeating unit. A method for producing a filter for a solid-state imaging device.
However, in formula (1), A is a hydrogen atom, a halogen atom, or an alkyl group. X is an oxygen atom, NH, or NR5, and R5 is an alkyl group. R1, R2, R3, and R4 each independently represent a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, -OR6, -OCO-R7, -NHCO-R8, - NHCONHR9, -OCONH-R10, -COOR11, -CONHR12, -COR13, -CONR14R15, -CN, or -CHO. Alternatively, R1, R2, R3, and R4 may form a cyclic structure by combining two of them. R6 to R15 are each independently an alkyl group, a substituted alkyl group, an aryl group, or a substituted aryl group.

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