TWI773645B - Photosensitive composition, pattern forming method, permanent film, and color filter for CMOS image sensor - Google Patents

Abstract

To provide a photosensitive composition capable of forming a film having excellent thermal fluidity and resolution, high residual film rate during development, and excellent long-term stability of transmittance, and a diagram of using the photosensitive composition A mold forming method, a permanent film formed using the photosensitive composition, and a color filter for a CMOS image sensor including the permanent film.

In the photosensitive composition containing an alkali-soluble polymer and a quinonediazide group-containing compound, as the alkali-soluble polymer, a constituent unit (a1) represented by the following formula (a-1), having A structural unit (a2) of a crosslinkable group, and a structural unit (a3) having a hydroxyalkyl group, and an alkali-soluble polymer having a mass average molecular weight of less than 15,000.

Description

Photosensitive composition, pattern forming method, permanent film, and color filter for CMOS image sensor

The present invention relates to a photosensitive composition comprising an alkali-soluble polymer and a compound containing a quinone diazide group.

Conventionally, in microfabrication of substrates used in semiconductor devices such as liquid crystal panels and CMOS (solid-state imaging devices), a photosensitive composition used to form a permanent film contains 4-hydroxyl group derived from methacrylic acid. Resin of the constituent unit of phenyl ester. Such a photosensitive composition is used to provide a permanent film having a high glass transition temperature (Tg) (for example, Patent Document 1).

However, a color filter used in CMOS and the like can be formed by, for example, applying a positive-type photosensitive composition on a substrate to form a coating film, and exposing and developing the coating film to form a coating film. The exposed part is removed and patterned.

However, when manufacturing a color filter on a board|substrate, the board|substrate which has a height difference of about 1-several micrometers may be used. In this case, the photosensitive composition is accumulated in the step portion, and it is difficult to deposit the photosensitive composition on the substrate. Coated to a uniform film thickness. Therefore, when a coating film made of a photosensitive composition is formed on a substrate having a level difference, the film thickness becomes thicker near the level difference.

For such reasons, when a patterned color filter is formed on a substrate having a level difference, there is a problem that the height of the pattern portion located near the level difference is higher than that of the other pattern portions.

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2010-54809

As a solution to such a problem, it is conceivable to form a spacer film on the substrate to reduce the level difference. First, the photosensitive composition is applied on a substrate having a step to form a coating film. Next, the coating film is exposed and developed to remove unnecessary exposed portions to form a stand-up film. Thereby, the level difference on the board|substrate can be made small.

However, as shown in FIG. 1 , when the coating film 11 is formed on the substrate 10 having the level difference, a slope shape is generated from the top of the level difference to the substrate surface in the vicinity of the top of the level difference. . Regarding the riser film, there is a problem that the inclined shape remains even if the riser film is formed.

When there is an inclination with a thick film thickness in the vicinity of the step portion of the riser film, it will be difficult to uniformly apply the photosensitive composition when forming the color filter.

For these reasons, a raised film system is required to have good thermal fluidity that can flow and be easily planarized by heating. In addition, the photosensitive composition system used in the formation of the booster film is required to have good resolution and a high residual film rate without excessive film reduction after development, and the booster film is also required: "Fig. Excellent long-term stability with no change in transmittance even with time after molding.”

The present invention has been made in view of the above-mentioned general problems, and an object of the present invention is to provide a photosensitive composition which is excellent in thermal fluidity and resolution, has a high residual film rate during development, and has stable transmittance over a long period of time. The invention provides a film having excellent properties, and provides a pattern forming method using the photosensitive composition, a permanent film formed using the photosensitive composition, and a color filter for a CMOS image sensor including the permanent film.

In order to solve the above-mentioned problems, the inventors of the present invention have conducted repeated and intensive studies. As a result, the inventors found that the above-mentioned problems can be solved by using a photosensitive composition comprising a specific alkali-soluble polymer and a quinonediazide group-containing compound, thereby completing the present invention.

The first aspect of the present invention is a photosensitive composition comprising an alkali-soluble polymer and a quinonediazide group-containing compound, characterized in that the alkali-soluble polymer comprises the following formula (a-1). The constituent unit (a1), the constituent unit (a2) having a crosslinkable group, and the constituent unit (a3) having a hydroxyalkyl group represented by a mass average molecular weight of less than 15,000,

[In the above formula (a-1), R ⁰ represents a hydrogen atom or a methyl group, R ¹ represents a single bond or an alkylene group with 1 to 5 carbon atoms, and R ² represents an alkane with 1 to 5 carbon atoms Base, a represents an integer from 1 to 5, b represents an integer from 0 to 4, and a+b represents 5 or less. Furthermore, when R ² is present at 2 or more, these R ² may be the same or different from each other].

The second aspect of the present invention is a pattern forming method, which is characterized by comprising the following steps: forming a coating film made of the photosensitive composition of the first aspect on a substrate having a level difference; The step of patterning by exposure and development; the step of heating the patterned coating film to a specified temperature to form a pattern.

The third aspect of the present invention is a permanent film characterized by being formed using the photosensitive composition of the first aspect.

A fourth aspect of the present invention is a CMOS image sensor A color filter is characterized by comprising the permanent film of the third aspect.

The present invention can provide a photosensitive composition capable of forming a film having excellent thermal fluidity and resolution, high residual film rate during development, and excellent long-term stability of transmittance, and a photosensitive composition using the photosensitive composition. A pattern forming method of a composition, a permanent film formed using the photosensitive composition, and a color filter for a CMOS image sensor including the permanent film.

10‧‧‧Substrate

11‧‧‧Coating film

1 is a cross-sectional view showing a simulation of a coating film formed on a substrate with a level difference.

2] (a) is a diagram showing an electron microscope image of the raised film obtained in Example 1; (b) is a diagram showing an electron microscope image of the raised film obtained in Comparative Example 8.

[The best form of implementing the invention]

Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention.

The photosensitive composition of the present invention contains an "alkali-soluble polymer" and a "quinonediazide group-containing compound". The following is about photosensitivity The composition may be described as "composition".

<Alkali-soluble polymer>

The alkali-soluble polymer contains a structural unit (a1) represented by the following formula (a-1), a structural unit (a2) having a crosslinkable group, and a structural unit (a3) having a hydroxyalkyl group.

[In the above formula (a-1), R ⁰ represents a hydrogen atom or a methyl group, R ¹ represents a single bond or an alkylene group with 1 to 5 carbon atoms, and R ² represents an alkane with 1 to 5 carbon atoms Base, a represents an integer from 1 to 5, b represents an integer from 0 to 4, and a+b represents 5 or less. Furthermore, when R ² is present at 2 or more, these R ² may be the same or different from each other].

In the above formula (a-1), R ⁰ is preferably a methyl group. (This constituent unit is also referred to as a "PQMA unit" hereinafter.

R ¹ is a single bond or a linear or branched alkylene group having 1 to 5 carbon atoms. Specific examples of R ¹ include methylene, ethylidene, propylidene, isopropylidene, n-butylene, isobutylene, tert-butylene, and pentylene, in addition to the single bond. base, isopentyl extension, neopentyl extension, etc. Among them, single bond, methylene group and ethylidene group are preferred. In particular, in the case of a single bond, it is preferable because the alkali solubility can be improved.

From the viewpoint of the effects of the present invention or the so-called ease of manufacture, a is preferably 1.

The hydroxyl group on the benzene ring is preferably bonded to the 4th position when the carbon atom bonded to R ¹ is used as a reference (1st position).

R ² is a straight-chain or branched-chain alkyl group having 1 to 5 carbon atoms. Specific examples of R ² include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl and the like. Among them, a methyl group or an ethyl group is preferable in terms of easy production.

As said structural unit (a1), the unit represented by following formula (a1-1) - (a1-3) is mentioned specifically,. Particularly preferred is the constituent unit represented by the formula (a1-2).

The structural unit (a1) is obtained by polymerizing the polymerizable monomers represented by the following formula (a1)', or by polymerizing the polymerizable monomers represented by the following formula (a1)' and other polymerizable monomers Copolymerization can be introduced into alkali-soluble polymers.

[In the above formula (a1)', R ⁰ , R ¹ , R ² , a, and b are the same as those described above.]

The structural unit (a2) is a structural unit having a crosslinkable group. The crosslinkable group is a functional group that is crosslinked by heat. The alkali-soluble polymer can form a permanent film excellent in long-term stability of transmittance by having the structural unit (a2). As a crosslinkable group, an epoxy group and an oxetanyl group are mentioned, for example. Among them, it is preferable that the structural unit (a2) has an epoxy group from the viewpoint of the easiness of production of the copolymer. When the structural unit (a2) has an epoxy group, the storage stability as a composition may decrease. However, the storage stability of a composition can be improved by using the copolymer containing the combination of the said structural unit (a1) and the structural unit (a2) as an alkali-soluble polymer.

The structural unit (a2) having an epoxy group as such a crosslinkable group, for example, by making glycidyl acrylate, glycidyl methacrylate, acrylic acid-β-methyl glycidyl ester, methacrylic acid-β -Glycidyl Methyl Acrylate, Glycidyl α-Ethyl Acrylate, Glycidyl α-N-Propyl Acrylate, Glycidyl α-N-Butyl Acrylate, 3,4-Epoxybutyl Acrylate, 3,4-Epoxybutyl methacrylate, 6,7-epoxyheptyl acrylate, 6,7-epoxyheptyl methacrylate, α-ethyl acrylate-6,7- Epoxy heptyl ester, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, methacrylic acid (3,4-epoxy It can be derived by copolymerizing a polymerizable monomer such as cyclohexyl) methyl ester. These constituent units (a2) may be alone or in combination of two or more.

As an especially preferable structural unit (a2), the structural unit represented by following formula (a2-1) or (a2-2) is mentioned. In terms of ease of manufacture, superiority in cost, and improvement in solvent resistance, it is preferable to use the constituent unit (a2).

[In the above formulas (a2-1) and (a2-2), R ³ represents a hydrogen atom or a methyl group].

The constitutional unit (a3) is a constitutional unit having a hydroxyalkyl group. In the hydroxyalkyl group, the alkyl group is linear or branched. The number of carbon atoms of the hydroxyalkyl group is not particularly limited, but, for example, 1 to 6 are preferable, and 2 to 4 are more preferable. The number of hydroxyl groups is not particularly limited, but usually 1 is preferred.

Structural unit (a3) having a hydroxyalkyl group, for example, by making (meth)acrylate-2-hydroxyethyl, (meth)acrylate-3-hydroxy-n-propyl, (meth)acrylate-4- Polymerizable monomers such as hydroxy-n-butyl ester, (meth)acrylate-5-hydroxy-n-pentyl ester, and (meth)acrylate-6-hydroxy-n-hexyl ester can be copolymerized and derived. These constituent units (a3) may be alone or in combination of two or more.

As a particularly preferable structural unit (a3), the following formula can be specifically exemplified The unit represented by (a3-1).

[In the above formula (a3-1), R ³ represents a hydrogen atom or a methyl group].

The alkali-soluble polymer can improve the solubility of the composition with respect to an alkali developing solution by containing the copolymer containing the structural unit (a3). In addition, the crosslinking property with the component (a2) becomes high, the difference (contrast) in the solubility of the exposed part and the unexposed part to the alkali developing solution becomes large, and it can fully function as a positive resist. .

Furthermore, it is particularly preferable that the alkali-soluble polymer contains the structural units (a1), (a2), and (a3) but does not contain the structural unit derived from (meth)acrylic acid. That is, it is especially preferable not to contain the structural unit which has a carboxyl group. Thereby, the stability of the photosensitive composition can be improved.

In the alkali-soluble polymer, the content of the structural unit (a1) is preferably more than 0% by mass and less than 40% by mass. Inclusion of constituent unit (a1) The upper limit of the amount is also preferably 20% by mass or less. As long as the content of the constituent unit (a1) is within the above-mentioned range, a permanent film having excellent long-term stability of transmittance can be easily formed by using the composition.

In the alkali-soluble polymer, the content of the structural unit (a2) is preferably 20% by mass or more, and more preferably 65% by mass or more. By making the content of the structural unit (a2) within the above-mentioned range, the crosslinking of the structural unit (a1) and the structural unit (a2) can be promoted, and the long-term stability of the transmittance can be easily formed by using the composition, and the permanent stability is excellent. membrane.

In the alkali-soluble polymer, the content of the structural unit (a3) is preferably more than 0 mass % and 20 mass % or more, and more preferably 10 mass % to 20 mass %. By making the content of the structural unit (a3) within the above range, the alkali solubility is excellent, and within the above range, as the content of the structural unit (a3) increases, the resolution of the composition can be expected to improve. .

The mass average molecular weight of the alkali-soluble polymer (Mw: measured value in terms of polystyrene by gel permeation chromatography (GPC), the same in this specification) is less than 15,000, and preferably 3,000 to 10,000. By making the mass average molecular weight of an alkali-soluble polymer into the said range, the film excellent in thermal fluidity can be formed. Moreover, in the said range, as the mass average molecular weight of an alkali-soluble polymer is small, the improvement of thermal fluidity can be expected.

The alkali-soluble polymer can be produced by known radical polymerization. That is, after dissolving the polymerizable monomer which can derive the said structural unit (a1), (a2), (a3), and a conventional radical polymerization initiator, it can manufacture by heating and stirring.

The alkali-soluble polymer may contain other polymers in addition to the above-mentioned copolymer. As another polymer, the polymer containing the structural unit (a3), the copolymer containing the structural unit (a1) and the structural unit (a3), the copolymer containing the structural unit (a2) and the structural unit (a3), etc. are mentioned. . The copolymer containing the structural unit (a1) and the structural unit (a3), and the copolymer containing the structural unit (a2) and the structural unit (a3), may be composed of the structural unit (a1) and the structural unit (a3), respectively The copolymer, and the copolymer formed by the structural unit (a2) and the structural unit (a3). Other copolymers may be used alone or in combination of two or more. The content of other copolymers is preferably 0 parts by mass to 50 parts by mass, and more preferably 0 parts by mass relative to 100 parts by mass of the copolymer containing the constituent units (a1), (a2), and (a3). ~30 parts by mass.

<Compounds containing quinonediazide>

In terms of the quinonediazide group-containing compound used as a sensitizer (PAC), specifically, a phenolic compound (also called a phenolic hydroxyl group-containing compound), a complete esterified product with a naphthoquinonediazide sulfonic acid compound, or Partially esterified.

Specific examples of the above-mentioned phenolic compounds include polyhydroxybenzophenones such as 2,3,4-trihydroxybenzophenone and 2,3,4,4'-tetrahydroxybenzophenone; see (4-hydroxyphenyl)methane, bis(4-hydroxy-3-methylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,3,5-trimethylphenyl)-2 -Hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-3-hydroxy Phenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-4- Hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-3-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2-hydroxybenzene bis(4-hydroxy-3,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-3,4 -Dihydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2,4-dihydroxyphenylmethane, bis(4-hydroxyphenyl)-3-methoxy-4 -Hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-4-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl) -3-Hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylbenzene 2,4-bis(3,5-dimethyl-4-hydroxybenzyl)-5-hydroxyphenol, 2,6-bis (2,5-dimethyl-4-hydroxybenzyl)-4-methylphenol and other linear 3-nucleated phenolic compounds; 1,1-bis[3-(2-hydroxy-5-methylbenzyl) -4-Hydroxy-5-cyclohexylphenyl]isopropane, bis[2,5-dimethyl-3-(4-hydroxy-5-methylbenzyl)-4-hydroxyphenyl]methane, bis[ 2,5-Dimethyl-3-(4-hydroxybenzyl)-4-hydroxyphenyl]methane, bis[3-(3,5-dimethyl-4-hydroxybenzyl)-4-hydroxy- 5-Methylphenyl]methane, bis[3-(3,5-dimethyl-4-hydroxybenzyl)-4-hydroxy-5-ethylphenyl]methane, bis[3-(3,5 -Diethyl-4-hydroxybenzyl)-4-hydroxy-5-methylphenyl]methane, bis[3-(3,5-diethyl-4-hydroxybenzyl)-4-hydroxy-5 -Ethylphenyl]methane, bis[2-hydroxy-3-(3,5-dimethyl-4-hydroxybenzyl)-5-methylphenyl]methane, bis[2-hydroxy-3-( 2-Hydroxy-5-methylbenzyl)-5-methylphenyl]methane, bis[4-hydroxy-3-(2-hydroxy-5-methylbenzyl)-5-methylphenyl]methane , bis[2,5-dimethyl-3-(2-hydroxy-5-methylbenzyl)-4-hydroxyphenyl]methane, etc. Linear tetranuclear phenolic compound; 2,4-bis[2-hydroxy-3-(4-hydroxybenzyl)-5-methylbenzyl]-6-cyclohexylphenol, 2,4-bis[4-hydroxyl -3-(4-Hydroxybenzyl)-5-methylbenzyl]-6-cyclohexylphenol, 2,6-bis[2,5-dimethyl-3-(2-hydroxy-5-methyl) Linear polyphenol compounds such as benzyl)-4-hydroxybenzyl]-4-methylphenol and other linear pentanuclear phenol compounds; bis(2,3,-trihydroxyphenyl)methane, bis(2,4 -Dihydroxyphenyl)methane, 2,3,4-trihydroxyphenyl-4'-hydroxyphenylmethane, 2-(2,3,4-trihydroxyphenyl)-2-(2',3' ,4'-Trihydroxyphenyl)propane, 2-(2,4-dihydroxyphenyl)-2-(2',4'-dihydroxyphenyl)propane, 2-(4-hydroxyphenyl)- 2-(4'-Hydroxyphenyl)propane, 2-(3-Fluoro-4-hydroxyphenyl)-2-(3'-fluoro-4'-hydroxyphenyl)propane, 2-(2,4- Dihydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(2,3,4-trihydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(2, 3,4-Trihydroxyphenyl)-2-(4'-hydroxy-3',5'-dimethylphenyl)propane and other bisphenol compounds; 1-[1-(4-hydroxyphenyl) Isopropyl]-4-[1,1-bis(4-hydroxyphenyl)ethyl]benzene, 1-[1-(3-methyl-4-hydroxyphenyl)isopropyl]-4-[ Polynuclear branched compounds such as 1,1-bis(3-methyl-4-hydroxyphenyl)ethyl]benzene; Condensed phenolic compounds such as 1,1-bis(4-hydroxyphenyl)cyclohexane, etc. .

These may be used alone or in combination of two or more.

As the above-mentioned naphthoquinonediazidesulfonic acid compound, naphthoquinone-1,2-diazide-5-sulfonic acid, naphthoquinone-1,2-diazide-4-sulfonic acid, etc. may be mentioned.

Examples of other quinonediazide-containing compounds include o-benzoquinonediazide, o-naphthoquinonediazide, o-anthraquinonediazide, or o-naphthoquinone Nucleus-substituted derivatives of compounds such as quinonediazide sulfonates. Furthermore, ortho-quinonediazidosulfonyl chloride, and compounds with hydroxyl or amine groups (such as phenol, p-methoxyphenol, dimethylphenol, hydroquinone, bisphenol, etc.) can also be used. Phenol A, naphthol, catechol, gallic phenol, gallic phenol monomethyl ether, gallic phenol-1,3-dimethyl ether, gallic acid, esterified or etherified with residual hydroxyl group The reaction product of gallic acid, aniline, p-aminodiphenylamine, etc.). These can be used alone or in combination of two or more.

These quinonediazide-containing compounds can be produced by, for example, combining a ginseng-type compound with naphthoquinone-1,2-diazide-5-sulfonyl chloride or naphthoquinone-1 ,2-diazido-4-sulfonyl chloride is fully esterified by condensation in a suitable solvent such as dioxane in the presence of a base such as triethanolamine, alkali carbonate, alkali bicarbonate, etc. or partial esterification. As a quinonediazide group-containing compound, naphthoquinonediazide sulfonate is preferable.

The content of the quinonediazide group-containing compound is preferably 5% by mass to 25% by mass, and more preferably 7.5% by mass to 15% by mass relative to the total solid content.

By setting the content of the quinonediazide group-containing compound to 5% by mass or more, a composition capable of forming a raised film with excellent resolution and high residual film rate can be easily obtained.

By setting the content of the quinonediazide group-containing compound to 25% by mass or less, a composition capable of forming a film having good sensitivity and excellent long-term stability of transmittance can be easily obtained.

<Organic solvent>

In order to improve coatability or adjust viscosity, the photosensitive composition is preferably used as a solution dissolved in an appropriate organic solvent.

Examples of the organic solvent include benzene, toluene, xylene, methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, propanol, butanol, hexanol, cyclohexanol, ethyl alcohol Glycol, Diethylene Glycol, Glycerol, Ethylene Glycol Monomethyl Ether, Ethylene Glycol Monoethyl Ether, Propylene Glycol Monomethyl Ether, Propylene Glycol Monoethyl Ether (PGME), Diethylene Glycol Monomethyl Ether ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 3-methoxybutyl acetate (MA), 3-methoxybutanol (BM ), 3-methyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, methyl carbonate, Ethyl carbonate, propyl carbonate, butyl carbonate or mixtures of these, etc.

The usage-amount of an organic solvent is not specifically limited. The usage-amount of an organic solvent is suitably set according to a coating film thickness so that it may become the density|concentration which can apply|coat a composition to a board|substrate etc.. Specifically, the solid content concentration of the photosensitive composition is preferably used within a range of 10% by mass to 50% by mass, preferably 15% by mass to 35% by mass.

<other ingredients>

The photosensitive composition may contain various additives such as surfactants, sensitizers, antifoaming agents, and crosslinking agents.

As the surfactant, a conventionally known one can be used. As the surfactant, anionic, cationic, nonionic or the like can be exemplified. compound. Specifically, X-70-090 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be mentioned. By adding a surfactant, it is easy to obtain a composition which is excellent in coatability and which can form a flat film.

As the sensitizer, those used in conventionally known positive-type resists can be used. As a defoaming agent, a conventionally known thing can be used. As a defoaming agent, a polysiloxane type compound and a fluorine type compound are mentioned.

As a crosslinking agent, the polymerizable compound which has an ethylenically unsaturated bond is mentioned. As such a compound, it is preferable to use a monofunctional, bifunctional, or trifunctional or higher (meth)acrylate from the viewpoint of improving the polymerizability and enhancing the strength of the obtained film.

Examples of monofunctional (meth)acrylates include 2-hydroxyethyl (meth)acrylate, carbitol (meth)acrylate, isobornyl (meth)acrylate, and 3-(meth)acrylate. Methoxybutyl ester, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, etc. Examples of commercially available monofunctional (meth)acrylates include ARONIX M-101, IsoM-111, IsoM-114 (manufactured by Toa Gosei Chemical Co., Ltd.), KAYARAD TC-110S, IsoTC- 120S (made by Nippon Kayaku Co., Ltd.), VISCOAT 158, Tong 2311 (made by Osaka Organic Chemical Industry Co., Ltd.), etc.

As bifunctional (meth)acrylate, ethylene glycol (meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, for example Acrylates, polypropylene glycol di(meth)acrylates, tetraethylene glycol di(meth)acrylates, bisphenoxyethanol diacrylates, etc. As a commercial item of bifunctional (meth)acrylate, ARONIX is mentioned, for example M-210, Same as M-240, Same as M-6200 (Toa Gosei Chemical Co., Ltd.), KAYARAD HDDA, Same as HX-220, Same as R-604 (Nippon Kayaku Co., Ltd.), VISCOAT 260, Same as 312. Same as 335HP (Osaka Organic Chemical Industry Co., Ltd.), etc.

Trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tris((meth)acryloyloxyethyl) as trifunctional or more (meth)acrylates, for example Phosphate ester, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. Examples of commercially available trifunctional or higher (meth)acrylates include ARONIX M-309, the same M-400, the same M-402, the same M-405, the same M-450, the same M-7100, the same M-8030, the same as M-8060 (made by Toa Synthetic Chemical Industry Co., Ltd.), KAYARAD TMPTA, the same as DPHA, the same as DPCA-20, the same as DPCA-30, the same as DPCA-60, the same as DPCA-120 (Nihon Kayaku Co., Ltd. ), VISCOAT 295, same 300, same 360, same GPT, same 3PA, same 400 (Osaka Organic Chemical Industry Co., Ltd.), etc. These crosslinking agents can be used alone or in combination.

<Preparation of photosensitive composition>

For the photosensitive composition according to the present invention, each component can be mixed (dispersed and kneaded) with a mixer such as a roller mill, a ball mill, a sand mill, etc., and as required, a membrane filter having a pore size of 5 μm can be used. filter) and other filters to filter and modulate.

<Formation of Raising Film>

Next, the method of forming a booster film on a board|substrate using the photosensitive composition of this invention is demonstrated.

First, the photosensitive composition is applied on a substrate having a level difference to form a coating film. The coating film is pre-baked to remove the solvent. A substrate made of, for example, glass, quartz, polysiloxane, transparent resin, or the like can be used. As a coating method, various methods, such as a spray method, a roll coating method, a spin coating method, etc., can be used. In addition, the conditions of the pre-baking will vary according to the type of each component or the mixing ratio, etc., for example, it may be a condition of about 1 minute to 10 minutes at 80°C to 120°C.

Next, the coating film is exposed to radiation such as ultraviolet rays through a positive mask, and is then developed with an alkaline developer to remove unnecessary exposed portions to form a stand-up film. As radiation used for exposure, visible light, ultraviolet rays, extreme ultraviolet rays, electron rays, X-rays, and the like can be used.

As the alkaline developer, inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, etc.; primary amines such as ethylamine, n-propylamine, etc. can be used; Secondary amines such as diethylamine, di-n-propylamine, etc.; tertiary amines such as trimethylamine, methyldiethylamine, dimethylethylamine, triethylamine, etc.; diethylamine Alkanolamines such as methylethanolamine, methyldiethanolamine, triethanolamine, etc.; pyrrole, piperidine, N-methylpiperidine, N-methylpyrrolidine, 1,8-diazabicyclo[5.4.0] Cyclic tertiary amines such as -7-undecene, 1,5-diazabicyclo[4.3.0]-5-nonene, etc.; aromatics such as pyridine, collins, lutidine, quinoline, etc. Group tertiary amines; aqueous solutions of quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, etc. Also, alkaline developer Appropriate amounts of water-soluble organic solvents such as methanol and ethanol and/or surfactants may also be added.

As a developing method, any of a drip method, a dipping method, a rinse method, etc. may be sufficient, and the developing time is usually 10 seconds to 180 seconds. After alkali development, for example, it can be washed with running water, and dried with compressed air or compressed nitrogen, for example, to form a pattern.

Next, by performing post-baking at a predetermined temperature (for example, 150° C. to 250° C.) and a predetermined time period with a heating device such as a hot plate or an oven, the above-mentioned booster film can be formed.

In addition, when the bumper film is formed by the above-mentioned method, as shown in FIG. 1 , the coating film has an inclined shape in the vicinity of the step. Before the heating of the coating film, there is an inclined portion (inclined portion) with a thick film thickness from the upper part of the level difference to the substrate surface at the position near the level difference of the riser film.

However, the thermal fluidity of the above-mentioned photosensitive composition is excellent. Therefore, when a raised film having an inclined portion is heated, the inclined portion disappears due to the flow of heat, and a flat raised film can be formed.

The raised film thus obtained has a flat and desired shape because it is formed using a photosensitive composition which is excellent in thermal fluidity and resolution and has a high residual film ratio at the time of development. Therefore, when the bumper film is formed by the above method, the material for forming the color filter can be easily and uniformly coated on the bumper film when the color filter is formed.

<color filter>

The color filter related to the present invention is formed on the above-mentioned raised film. in order to make As this color filter, first, a resin pattern (black matrix) is formed in the same manner as the above-mentioned method using a photosensitive composition in which a black pigment is dispersed. Next, colorants (RGB), cyan, magenta, and yellow, or complementary colorants of cyan, magenta, yellow, and green are used ( The photosensitive composition of CMY or CMYG) is similarly patterned in the area divided by the black matrix to form pixel patterns of various colors. Thereby, a color filter is formed.

In addition, when the color filter is produced, inks of red, green, and blue are ejected from the ink jet nozzles to each area divided by the black matrix, and accumulated by heat or light. The ink is hardened, and color filters can also be made.

The photosensitive composition according to the present invention is used as a booster film that is used when forming a color filter for CMOS. However, the present invention is not limited to this and need not be discussed further. For example, it can also be used as a lifter film used when patterning a color filter for liquid crystal.

The following examples illustrate the present invention in more detail, but the present invention is not limited to these examples.

<Example 1 to Example 12, Comparative Example 1 to Comparative Example 8>

Each component was constituted by the mass ratio shown in the following Table 1, the polymerizable monomer was mixed so that the mass average molecular weight (Mw) shown in Table 1 was obtained, and an alkali-soluble polymer was prepared according to a conventional method.

In Table 1, the structural unit (a1) is derived from 4-hydroxyphenyl methacrylate (PQMA), the structural unit (a2) is derived from glycidyl methacrylate (GMA), and the structural unit (a3) is derived from 2-hydroxyethyl methacrylate (2-HEMA).

In Table 1, the numbers of the constituent units (a1), (a2) and (a3) are the mass ratios in the alkali-soluble polymer.

As a sensitizer, 1,2-naphthoquinonediazide of 4-[2-[4-[1,1bis(4-hydroxyphenyl)ethyl]phenyl]propan-2-yl]phenol was used -5-sulfonate (3 moles). As a solvent, a mixed solvent of propylene glycol monoethyl ether (PGME):propylene glycol monomethyl ether acetate (PGMEA)=6:4 (mass ratio) was used.

The obtained photosensitive compositions of Examples 1 to 12 and Comparative Examples 1 to 8 were coated on a glass substrate using a spin coater so that the film thickness might be 0.9 μm, and then the photosensitive compositions were heated on a hot plate at 110° C. for 120 seconds. This was dried to obtain a coating film. The coating film was exposed through a positive mask using a mirror projection aligner (trade name: TME-150RTO, manufactured by TOPCON). Next, it was immersed for 90 seconds in a NaOH·Na ₂ CO ₃ mixed aqueous solution (0.825 mass %) (developing solution) at 26° C. to perform development, and was rinsed with pure water to remove unnecessary parts. After that, post-baking was performed at 230° C. for 20 minutes.

The respective items of long-term stability (transmittance), thermal fluidity, resolution, and residual film rate were evaluated for the raised films of the respective Examples and Comparative Examples obtained as described above. Each evaluation criterion is as follows.

<Evaluation of long-term stability (transmittance)>

The test of standing in an oven at 150° C. for 2000 hours was performed on the raised films obtained in the respective Examples and Comparative Examples, and the change in transmittance of light having a wavelength of 400 nm as a visible region was measured.

Each evaluation criterion is as follows.

○: Transmittance after 2000 hours is 83% or more

△: The transmittance after 2000 hours is 80% or more

×: Transmittance less than 80% after 2000 hours

As can be seen from the results in Table 1, the long-term stability of the transmittance of the stand-up films formed using the photosensitive compositions of the Examples was excellent. In the Examples in which the ratio of the constituent unit (a1) was 20 mass % or less, the transmittance was particularly high, whereas the comparative example in which the ratio of the constituent unit (a1) was larger had a lower transmittance. From this, it can be seen that long-term stability (transmittance) can be improved by reducing the ratio of the constituent unit (a1).

It can be seen that the long-term stability (transmittance) is improved when the addition amount of the sensitizer is reduced. The addition amount of the photosensitizer is found to be preferably 15% by mass or less in terms of long-term stability (transmittance).

<Evaluation of thermal fluidity>

The photosensitive composition of each Example and the comparative example was heated at 120 degreeC for 1 minute, and the surface of the cured film after heating was observed with a scanning electron microscope (SEM). Furthermore, the photosensitive composition obtained in Comparative Example 8 was not sufficiently flattened under the same heating conditions as in Example 1, so it was heated at 160° C. for 5 minutes and further heated at 220° C. for 5 minutes. Each evaluation criterion is as follows.

○: Sufficient planarization is observed

△: Insufficient planarization was observed

As can be seen from the results in Table 1, when the photosensitive compositions of Examples 1 to 12 and Comparative Examples 1 to 7 containing an alkali-soluble polymer having a mass average molecular weight (Mw) of 6000 were used, a sufficiently flat pad was formed. High film. On the other hand, when the photosensitive composition of Comparative Example 8 containing an alkali-soluble polymer having a large mass average molecular weight (Mw) of 15,000 was used, a sufficiently flat bumper film could not be formed.

The surface of the cured film formed using the photosensitive composition of Example 1 and Comparative Example 8 was observed with a scanning electron microscope (SEM), and the result is shown in FIG. 2 . As can be seen from FIG. 2 , when the photosensitive composition of Example 1 containing an alkali-soluble polymer having a small mass average molecular weight (Mw) of 6000 was used, the film-forming surface was sufficiently flattened. On the other hand, when the photosensitive composition of Comparative Example 8 containing an alkali-soluble polymer having a mass average molecular weight (Mw) of 15,000 was used, it was found that the film-forming surface was not sufficiently flattened.

From these results, it can be seen that the photosensitive composition contains The smaller the mass-average molecular weight (Mw) of the alkali-soluble polymer, the better the thermal fluidity of the photosensitive composition, and a flat bumper film can be formed even if the bumper film is formed on a substrate with a step difference.

<Evaluation of resolution>

The shapes of the raised films obtained in the Examples and Comparative Examples were observed with a scanning electron microscope (SEM), and the widths of white bands appearing around the patterns were compared. Each evaluation criterion is as follows. Moreover, the white band can only be confirmed when the size of the bottom part of the pattern is larger than that of the top part. The width of the white band is the difference in size between the top portion and the bottom portion, and represents the degree of the tapered shape. The smaller the width of the white band, the higher and better the verticality of the pattern.

○: The width of the white band is small

△: The width of the white band is medium

×: The width of the white band is large

As can be seen from the results in Table 1, the photosensitive compositions of the respective Examples were all excellent in resolution.

The result of observation of the surface of the booster film formed by using the photosensitive composition of Comparative Example 3 with a scanning electron microscope (SEM), and the results of the booster film formed by using the photosensitive composition of Comparative Example 6 By comparing the results of observation with a scanning electron microscope (SEM) on the surface of the photosensitive composition, it can be seen that by increasing the ratio of the constituent unit (a1), the width of the white band will be reduced, and the alkali solubility of the photosensitive composition will be improved. Resolution will improve.

From the feeling that Examples 1, 4, 7, 8 and Comparative Example 6 will be used The surface of the raised film formed by the optical composition was observed with a scanning electron microscope (SEM), and it can be seen that compared with "Comparative Example 6" (which contains no added structural unit (a3)) The photosensitive composition of the alkali-soluble polymer), the alkali-solubility of the photosensitive composition of "Examples 1, 4, 7" (which is an alkali-soluble polymer to which the structural unit (a3) is added) is improved, and Improve resolution.

However, with regard to Example 8, if the ratio of the structural unit (a3) is excessively increased, the solubility will increase and the size of the space portion will increase, so the ratio of the structural unit (a3) in the alkali-soluble polymer is preferable. is not more than 20% by mass.

In the photosensitive compositions of Examples 3, 4, 5, and 12, the ratio of the structural unit (a3) in the alkali-soluble polymer was all 12.5% by mass, and the amount of the photosensitive agent added was different. From the results of observing the surfaces of the booster films formed using the photosensitive compositions of Examples 3, 4, 5, and 12 with a scanning electron microscope (SEM), it can be seen that by adding a photosensitive agent When the amount is 5% by mass or more, preferably 7.5% by mass or more, a photosensitive composition having more excellent resolution can be obtained.

<Assessment of residual film rate>

The ratio of the film thickness of the raised film measured after development to the film thickness of the raised film measured before development. The film thickness of the raised film was measured using a stylus-type surface profiler (Dektak 150, manufactured by Ulvac Co., Ltd.). Each evaluation criterion is as follows.

○: The residual film ratio is 90% or more.

△: The residual film ratio is less than 90%.

The photosensitive compositions of Examples 1, 4, 6, 8 and Comparative Example 6 (including the ratio of the structural unit (a1) are both 20% by mass, and the amount of the photosensitive agent added is the same as 10% by mass, but the structural unit Table 2 shows the residual film ratio in the case where the ratio of (a3) is an alkali-soluble polymer which is different from each other) to form a raised film.

The photosensitive compositions of Examples 1, 2, 9, and 10 (including alkali-soluble polymers whose ratio of the structural unit (a3) is the same as 10% by mass, but the addition amounts of the photosensitive agents are different from each other) were used to Table 3 shows the residual film ratio in the case of forming the booster film.

The photosensitive compositions of Examples 3, 4, 5, and 12 (including alkali-soluble polymers with the same ratio of the structural unit (a3) as 12.5% by mass, but the addition amounts of the photosensitive agents are different from each other) were used. Table 4 shows the residual film ratio in the case of forming the booster film.

Pads were formed using the photosensitive compositions of Examples 6, 7, and 11 (which included an alkali-soluble polymer having the same ratio of the constituent unit (a3) as 15% by mass, but the addition amounts of the photosensitive agents were different from each other) The residual film ratio in the case of high film is shown in Table 5.

It can be seen from the results in Table 2 that when the ratio of the constituent unit (a3) The smaller the value, the higher the resistance of the booster film formed using the photosensitive composition to the developer, and the higher the residual film ratio. Also, as can be seen from Tables 2 to 5, by making the addition amount of the photosensitive agent to be 5 mass % or more, preferably 7.5 mass % or more, the use of the photosensitive composition for the formation of the pad height film to the developer. The resistance will increase, and the residual film rate will increase. It can also be seen that as the ratio of the constituent unit (a3) increases, the residual film rate tends to decrease, but the decrease in the residual film rate can be suppressed by increasing the addition amount of the photosensitizer.

10‧‧‧Substrate

11‧‧‧Coating film

Claims (8)

A photosensitive composition comprising an alkali-soluble polymer and a quinonediazide group-containing compound, wherein the alkali-soluble polymer comprises a structural unit (a1) represented by the following formula (a-1), The constituent unit (a2) having a crosslinkable group and the constituent unit (a3) having a hydroxyalkyl group, but not including the constituent unit containing an alkoxysilyl group, the aforementioned crosslinking group is an epoxy group, and the aforementioned constituent unit has a hydroxyl group The structural unit (a3) of the alkyl group is derived from (meth)acrylic acid-2-hydroxyethyl ester, (meth)acrylic acid-3-hydroxy-n-propyl ester, (meth)acrylic acid-4-hydroxy-n- The unit of the polymerizable monomer selected from the group consisting of butyl ester, (meth)acrylate-5-hydroxy-n-pentyl ester, and (meth)acrylate-6-hydroxy-n-hexyl ester, the aforementioned alkali-soluble The mass-average molecular weight of the polymer is less than 15,000,

[In the above formula (a-1), R ⁰ represents a hydrogen atom or a methyl group, R ¹ represents a single bond or an alkylene group with 1 to 5 carbon atoms, and R ² represents an alkane with 1 to 5 carbon atoms base, a represents an integer from 1 to 5, b represents an integer from 0 to 4, a+b represents 5 or less, and when R ² is 2 or more, these R ² may be the same or different from each other]. The photosensitive composition of Claim 1 whose content of the said structural unit (a3) in the said alkali-soluble polymer is more than 0 mass % and less than 20 mass %. The photosensitive composition of Claim 1 whose content of the said structural unit (a1) in the said alkali-soluble polymer is more than 0 mass % and less than 40 mass %. The photosensitive composition according to claim 1, wherein the alkali-soluble polymer does not contain a structural unit derived from (meth)acrylic acid. The photosensitive composition according to claim 1, wherein the content of the quinonediazide group-containing compound is 5.0 to 25% by mass relative to the mass of the solid content of the photosensitive composition. A pattern forming method, which is characterized by comprising the following steps: forming a coating film formed from the photosensitive composition of claim 1 on a substrate having a level difference; patterning the coating film by exposing and developing The step of forming a pattern; the step of heating the patterned coating film to a specified temperature to form a pattern. A permanent film characterized by being formed using the photosensitive composition of claim 1. A color filter for a CMOS image sensor is characterized by comprising the permanent film of claim 7.

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