JP7466385B2 - Photocurable composition and pattern forming method - Google Patents

Description

The present invention relates to a photocurable composition and a pattern forming method.

Lithography is a core technology in the manufacturing process of semiconductor devices, and with the recent increase in the integration density of semiconductor integrated circuits (ICs), wiring is becoming finer. Typical methods for finer wiring include shortening the wavelength of the light source using a shorter wavelength light source, such as a KrF excimer laser, an ArF excimer laser, an _F2 laser, EUV (extreme ultraviolet light), EB (electron beam), or X-rays, and increasing the numerical aperture (NA) of the lens of an exposure device (increasing NA).

In this context, nanoimprint lithography, in which a mold having a predetermined pattern is pressed against a resin film formed on a substrate to transfer the pattern of the mold to the resin film, is gaining attention in terms of productivity, etc. as a method for forming fine semiconductor patterns.
In nanoimprint lithography, a photocurable composition containing a photocurable resin that is cured by light (ultraviolet rays, electron beams) is used. In this case, a mold having a predetermined pattern is pressed against a resin film containing the photocurable resin, and then the photocurable resin is cured by irradiating it with light, and thereafter, the mold is peeled off from the resin cured film to obtain a transfer pattern (structure).

The photocurable composition used in nanoimprint lithography is required to have the following characteristics: applicability when applied to a substrate by spin coating or the like, and curability by heating or exposure. If the applicability to the substrate is poor, the film thickness of the photocurable composition applied to the substrate varies, which tends to reduce the pattern transferability when the mold is pressed against the resin film. In addition, the curability is an important characteristic for maintaining the pattern formed by pressing the mold to the desired dimensions. In addition, the photocurable composition is also required to have good mold releasability when the mold is peeled off from the resin cured film.
For example, Patent Document 1 discloses a composition for nanoimprints that contains a siloxane polymer having a polymerizable group that is polymerized by irradiation with light. This composition can improve mold releasability.

JP 2016-207685 A

In recent years, the application of nanoimprint lithography has been considered in order to reduce power consumption by improving the light extraction efficiency of liquid crystal displays. Cycloolefin polymer (COP) films, which have high total light transmittance and low birefringence, are often used as the base material for liquid crystal displays around polarizing components. It is expected that large-area simultaneous pattern transfer, a feature of the imprint process, will enable patterning that can improve the light extraction efficiency of plastic films.

Although COP films have excellent optical properties for use as display materials, they are known to have poor adhesion to topcoat layers because they do not have polar groups on the surface layer. Methods of modifying the film surface and exposing polar groups, such as corona discharge treatment, are known as a means of improving adhesion. However, when a surface treatment process is performed, the number of processes increases during mass production, which is problematic in terms of cost and process complexity. For this reason, there has been a demand for a topcoat material that has good adhesion even without applying a surface treatment to the COP film.

The present invention was made in consideration of the above circumstances, and aims to provide a photocurable composition that has good adhesion to a substrate, and a pattern forming method.

In order to solve the above problems, the present invention employs the following configuration.
That is, a first aspect of the present invention is a photocurable composition containing component (A): a carboxy group-containing (meth)acrylate, component (B): an acid anhydride, and component (D): a photopolymerization initiator.

The second aspect of the present invention is a pattern forming method comprising the steps of forming a resin film on a substrate using the photocurable composition of the first aspect of the present invention, pressing a mold having a concave-convex pattern against the resin film to transfer the concave-convex pattern to the resin film, exposing the resin film to which the concave-convex pattern has been transferred while pressing the mold against the resin film to form a cured resin film, and peeling the mold from the cured resin film.

The present invention provides a photocurable composition that has good adhesion to a substrate, and a pattern forming method.

1A to 1C are schematic process diagrams illustrating an embodiment of a nanoimprint pattern formation method. FIG. 2 is a schematic process diagram illustrating an example of an optional process.

In this specification and claims, the term "aliphatic" is a relative concept to aromaticity and is defined as meaning a group, compound, etc. that does not have aromaticity.
Unless otherwise specified, the term "alkyl group" includes linear, branched and cyclic monovalent saturated hydrocarbon groups. The same applies to the alkyl group in an alkoxy group.
Unless otherwise specified, the term "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups.
The term "halogenated alkyl group" refers to an alkyl group in which some or all of the hydrogen atoms have been substituted with halogen atoms, and examples of the halogen atoms include fluorine, chlorine, bromine and iodine atoms.
The term "fluorinated alkyl group" or "fluorinated alkylene group" refers to an alkyl group or alkylene group in which some or all of the hydrogen atoms have been substituted with fluorine atoms.
The term "structural unit" refers to a monomer unit that constitutes a polymeric compound (resin, polymer, copolymer).
The term "(meth)acrylate" refers to at least one of acrylate and methacrylate.
The phrase "optionally having a substituent" includes both the case where a hydrogen atom (--H) is replaced with a monovalent group and the case where a methylene group (--CH ₂ -) is replaced with a divalent group.
The term "exposure" is intended to include any concept including irradiation with radiation.

The term "structural unit derived from an acrylate ester" refers to a structural unit formed by cleavage of the ethylenic double bond of an acrylate ester.
An "acrylic acid ester" is a compound in which the hydrogen atom at the terminal carboxy group of acrylic acid (CH ₂ ═CH—COOH) is substituted with an organic group.
In the acrylic acid ester, the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The substituent (R ^α0 ) substituting the hydrogen atom bonded to the carbon atom at the α-position is an atom or group other than a hydrogen atom, and examples thereof include an alkyl group having 1 to 5 carbon atoms and a halogenated alkyl group having 1 to 5 carbon atoms. In addition, it also includes an itaconic acid diester in which the substituent (R ^α0 ) is substituted with a substituent containing an ester bond, and an α-hydroxyacrylic ester in which the substituent (R ^α0 ) is substituted with a hydroxyalkyl group or a group obtained by modifying the hydroxyl group of the hydroxyalkyl group. The carbon atom at the α-position of an acrylic acid ester refers to the carbon atom to which the carbonyl group of acrylic acid is bonded, unless otherwise specified.
Hereinafter, an acrylic acid ester in which the hydrogen atom bonded to the carbon atom at the α-position is replaced with a substituent may be referred to as an α-substituted acrylic acid ester. In addition, acrylic acid esters and α-substituted acrylic acid esters may be collectively referred to as "(α-substituted) acrylic acid esters." In addition, an acrylic acid in which the hydrogen atom bonded to the carbon atom at the α-position is replaced with a substituent may be referred to as an α-substituted acrylic acid. In addition, acrylic acid and α-substituted acrylic acid may be collectively referred to as "(α-substituted) acrylic acid."

The alkyl group as the substituent at the α-position is preferably a linear or branched alkyl group, and specific examples thereof include alkyl groups having 1 to 5 carbon atoms (such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group).
Specific examples of the halogenated alkyl group as the substituent at the α-position include groups in which some or all of the hydrogen atoms of the above-mentioned "alkyl group as the substituent at the α-position" are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferred.
Specific examples of the hydroxyalkyl group as the substituent at the α-position include the above-mentioned "alkyl group as the substituent at the α-position" in which some or all of the hydrogen atoms have been substituted with hydroxyl groups. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1 to 5, and most preferably 1.

In this specification and claims, some structures represented by chemical formulas may have asymmetric carbons, and enantiomers or diastereoisomers may exist. In such cases, a single formula represents all of the isomers. These isomers may be used alone or as a mixture.

(Photocurable composition)
The photocurable composition according to the first aspect of the present invention contains a component (A): a carboxy group-containing (meth)acrylate, a component (B): an acid anhydride, and a component (D): a photopolymerization initiator.

<Component (A)>
The component (A) is a carboxy group-containing (meth)acrylate.
The term "carboxy group-containing (meth)acrylate" refers to a compound that contains a carboxy group at the ester moiety of a (meth)acrylic acid ester.
Examples of the component (A) include compounds represented by general formula (A0) shown below.

［式中、Ｒ^１は、水素原子又はメチル基を表す。Ｒ^０は、２価の有機基を表す。］

[In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ⁰ represents a divalent organic group.]

In the formula (A0), R ⁰ represents a divalent organic group. Examples of the divalent organic group in R ⁰ include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

When ^R0 is a divalent hydrocarbon group which may have a substituent, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and is preferably an aliphatic hydrocarbon group. The hydrocarbon group preferably has 1 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and even more preferably 2 to 6 carbon atoms.
The aliphatic hydrocarbon group in R ⁰ may be saturated or unsaturated, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group in R ⁰ include linear or branched aliphatic hydrocarbon groups and aliphatic hydrocarbon groups containing a ring in the structure, and linear aliphatic hydrocarbon groups and aliphatic hydrocarbon groups containing a ring in the structure are preferred.

The straight-chain aliphatic hydrocarbon group for R ⁰ is preferably a straight-chain alkylene group, and specific examples thereof include a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) ₂ -], a trimethylene group [-(CH ₂ ) ₃ -], a tetramethylene group [-(CH ₂ ) ₄ -], a pentamethylene group [-(CH ₂ ) ₅ -], and the like.
The branched aliphatic hydrocarbon group for R ⁰ is preferably a branched alkylene group, and specific examples thereof include alkylmethylene groups such as -CH(CH ₃ )-, -CH(CH ₂ CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CH ₃ )(CH ₂ CH ₃ )-, -C(CH ₃ )(CH ₂ CH ₂ CH ₃ )-, and -C(CH ₂ CH ₃ ) ₂ -; alkylethylene groups such as -CH(CH ₃ )CH ₂ -, -CH(CH ₃ ) _CH (CH ₃ )-, -C ₍ CH ₃ ) _{2 CH 2 - ,} -CH(CH ₂ CH ₃ )CH ₂ -, and -C(CH ₂ CH ₃ ) _{2 -CH 2 -} ; )CH ₂ --; and alkyl alkylene groups such as alkyl tetramethylene groups such as --CH(CH ₃ )CH ₂ CH ₂ CH ₂ -- and --CH ₂ CH(CH ₃ )CH ₂ CH ₂ --.

The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, and a carbonyl group.

When R ⁰ is a divalent linking group containing a heteroatom, preferred examples of the linking group include -O-, -C(=O)-O-, -O-C(=O)-, -C(=O)-, -O-C(=O)-O-, -C(=O)-NH-, -NH-, -S-, -S(=O) ₂ -, -S(=O) ₂ -O-, etc. Among these, -O-, -C(=O)-O-, and -O-C(=O)- are preferred.

Examples of the aliphatic hydrocarbon group containing a ring in the structure include an alicyclic hydrocarbon group (a group in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring), a group in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, a group in which an alicyclic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group, etc. Examples of the linear or branched aliphatic hydrocarbon group include the same as the linear aliphatic hydrocarbon group or the branched aliphatic hydrocarbon group.
The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms.
The alicyclic hydrocarbon group may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

The aromatic hydrocarbon group as the divalent hydrocarbon group for R ⁰ is a hydrocarbon group having an aromatic ring.
The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, even more preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. However, this carbon number does not include the number of carbon atoms in the substituents.
Specific examples of the aromatic ring contained in the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a heteroatom, etc. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom.
Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring (arylene group); a group in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring (aryl group) has been substituted with an alkylene group (for example, a group in which one hydrogen atom has been further removed from the aryl group in an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The number of carbon atoms in the alkylene group (the alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

In this embodiment, the component (A) is preferably a compound represented by the following general formula (A1):

［式中、Ｒ^１は、水素原子又はメチル基を表す。Ｒ^２は、炭素数１～４の直鎖状又は分岐鎖状のアルキレン基を表す。Ｒ^３は、２価の有機基を表す。］

[In the formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a linear or branched alkylene group having 1 to 4 carbon atoms, and R ³ represents a divalent organic group.]

In the formula (A1), R ² represents a linear or branched alkylene group having 1 to 4 carbon atoms, and preferably a linear or branched alkylene group having 2 or 3 carbon atoms.

In the formula (P1), ^R3 represents a divalent organic group. The divalent organic group in ^R3 is the same as the divalent organic group in ^R0 in the general formula (A0).
Among these, ^R3 is preferably a linear or branched alkylene group, a group in which two hydrogen atoms have been removed from a monocycloalkane, or a group in which two hydrogen atoms have been removed from benzene.

In this embodiment, the component (A) is preferably at least one selected from the group consisting of compounds represented by the following general formulas (A1-1) to (A1-3).

［式中、Ｒ^１１～Ｒ^１３は、それぞれ独立に、水素原子又はメチル基を表す。Ｒ^２１～Ｒ^２３は、それぞれ独立に、炭素数１～４の直鎖状又は分岐鎖状のアルキレン基を表す。Ｒ^３１は、直鎖状若しくは分岐鎖状のアルキレン基を表す。Ｒ^３２は、モノシクロアルカンから２個の水素原子を除いた基を表す。Ｒ^３３は、ベンゼンから２個の水素原子を除いた基を表す。］

[In the formula, R ¹¹ to R ¹³ each independently represent a hydrogen atom or a methyl group. R ²¹ to R ²³ each independently represent a linear or branched alkylene group having 1 to 4 carbon atoms. R ³¹ represents a linear or branched alkylene group. R ³² represents a group obtained by removing two hydrogen atoms from a monocycloalkane. R ³³ represents a group obtained by removing two hydrogen atoms from benzene.]

As the component (A), a commercially available product can be obtained and used.
Commercially available products of the component (A) include monohydroxyethyl phthalate acrylate, manufactured by Toagosei Co., Ltd., product name "Aronix M-5400"; 2-acryloyloxyethyl succinic acid, manufactured by Kyoeisha Chemical Co., Ltd., product name "HOA-MS"; 2-acryloyloxyethyl hexahydrophthalic acid, manufactured by Kyoeisha Chemical Co., Ltd., product name "HOA-HH"; and 2-methacryloyloxyethyl phthalic acid, manufactured by Shin-Nakamura Chemical Co., Ltd., product name "NK Ester CB-1".

In the photocurable composition of this embodiment, the component (A) may be used alone or in combination of two or more types.
The content of the (A) component is preferably 35 to 90 parts by mass, more preferably 40 to 80 parts by mass, and even more preferably 40 to 70 parts by mass, relative to 100 parts by mass of the total of the (A) component and the (B) and (C) components described below.
When the content of component (A) is at least the lower limit of the preferred range, the curability of the photocurable composition is improved, whereas when the content is at most the upper limit of the preferred range, the coatability onto a substrate is further improved.

<Component (B)>
The component (B) is an acid anhydride. The acid anhydride is not particularly limited, but is preferably a carboxylic acid anhydride, and examples thereof include monobasic anhydrides such as methacrylic anhydride, acrylic anhydride, acetic anhydride, propionic anhydride, and benzoic anhydride; and dibasic anhydrides such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, succinic anhydride, and glutaric anhydride.

In this embodiment, the component (B) is preferably an acid anhydride having a photocurable polar group.
The term "photocurable polar group" refers to a group that enables compounds to polymerize together by radical polymerization or the like upon irradiation with light, and is, for example, a group that contains a multiple bond between carbon atoms, such as an ethylenic double bond.
Examples of the polymerizable functional group include vinyl group, allyl group, acryloyl group, methacryloyl group, fluorovinyl group, difluorovinyl group, trifluorovinyl group, difluorotrifluoromethylvinyl group, trifluoroallyl group, perfluoroallyl group, trifluoromethylacryloyl group, nonylfluorobutylacryloyl group, vinyl ether group, fluorine-containing vinyl ether group, allyl ether group, fluorine-containing allyl ether group, styryl group, vinylnaphthyl group, fluorine-containing styryl group, fluorine-containing vinylnaphthyl group, norbornyl group, fluorine-containing norbornyl group, and silyl group. Among these, vinyl group, allyl group, acryloyl group, and methacryloyl group are preferred, and acryloyl group and methacryloyl group are more preferred.
Examples of the acid anhydride having a photocurable polar group include methacrylic anhydride, acrylic anhydride, and maleic anhydride.

In the photocurable composition of this embodiment, the component (B) may be used either as a single type alone, or as a combination of two or more types.
The content of the (B) component is preferably 1 to 50 parts by mass, more preferably 5 to 50 parts by mass, and even more preferably 10 to 50 parts by mass, relative to 100 parts by mass of the total of the (A) component and the (B) and (C) components described below.
When the content of component (B) is at least the lower limit of the preferred range, the adhesion between the substrate and the cured resin film is further improved, whereas when the content is at most the upper limit of the preferred range, the curability of the photocurable composition is improved.

<Component (D)>
The component (D) is a photopolymerization initiator.
The component (D) is a compound that initiates or accelerates polymerization of the component (A) upon exposure to light.

Examples of the (D) component include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, bis(4-dimethylaminophenyl)ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-buta Non-1, ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(o-acetyloxime), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 4-benzoyl-4'-methyldimethylsulfide, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, butyl 4-dimethylaminobenzoate, 4-dimethylamino-2-ethylhexylbenzoic acid, 4-dimethylamino-2-isoamylbenzoic acid, benzyl-β-methoxyethyl acetal, benzyl dimethyl ketal, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, methyl o-benzoylbenzoate Thiol, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 1-chloro-4-propoxythioxanthone, thioxanthene, 2-chlorothioxanthene, 2,4-diethylthioxanthene, 2-methylthioxanthene, 2-isopropylthioxanthene, 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-diphenylanthraquinone, azobisisobutyronitrile, benzoyl peroxide, cumene peroxide, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)-imidazolyl dimer benzoin, benzophenone, 2-chlorobenzophenone, p,p'-bisdimethylaminobenzophenone, 4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, 3,3-dimethyl-4-methoxybenzophenone, benzoyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, benzoin butyl ether, acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, p-tert-butylacetophenone, p-dimethylaminoacetophenone acetophenone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, α,α-dichloro-4-phenoxyacetophenone, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, dibenzosuberone, pentyl-4-dimethylaminobenzoate, 9-phenylacridine, 1,7-bis-(9-acridinyl)heptane, 1,5-bis-(9-acridinyl)pentane, 1,3-bis-(9-acridinyl)propane, p-methoxytriazine, 2,4,6-tris(trichloromethyl)-s-triazine, 2-methyl-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(5-methylfuran-2-yl)ethenyl]-4,6-bis (trichloromethyl)-s-triazine, 2-[2-(furan-2-yl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(4-diethylamino-2-methylphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(3,4-dimethoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-ethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-n-butoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis-trichloromethyl-6-(3-bromo- 4-methoxy)phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)phenyl-s-triazine, 2,4-bis-trichloromethyl-6-(3-bromo-4-methoxy)styrylphenyl-s-triazine, 2,4-bis-trichloromethyl-6-(2-bromo-4-methoxy)styrylphenyl-s-triazine; ketone peroxides such as methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, and cyclohexanone peroxide; diacyl peroxides such as isobutyryl peroxide and bis(3,5,5-trimethylhexanoyl)peroxide; p-menthane hydroperoxide, 1,1,3,3-tetramethyl Examples of such peroxy compounds include hydroperoxides such as butyl hydroperoxide; dialkyl peroxides such as 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane; peroxyketals such as 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane; peroxyesters such as t-butylperoxyneodecanoate and 1,1,3,3-tetramethylperoxyneodecanoate; peroxydicarbonates such as di-n-propyl peroxydicarbonate and diisopropyl peroxydicarbonate; and azo compounds such as azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobisisobutyrate.

Among the above, hydroxycyclohexyl phenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide are preferred.

As the component (C), a commercially available product can be used.
Commercially available products of the component (C) include products manufactured by BASF under the names "IRGACURE 907", "IRGACURE 369", and "IRGACURE 819", and products manufactured by IGM Resins B.V. under the name "Omnirad 184".

In the photocurable composition according to the embodiment, the component (D) may be used alone or in combination of two or more types.
The content of the (D) component is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 5 to 15 parts by mass, relative to 100 parts by mass of the total of the (A) component, the (B) component, and the (C) component described below. By setting the content of the (D) component within the above preferred range, the photocurability is further improved.

<Optional ingredients>
The photocurable composition of the present embodiment may contain, in addition to the components (A), (B), and (D), optionally further contain a component (C): a photopolymerizable monomer having two or more polymerizable functional groups (excluding the component (A)) and/or a compatible additive, for example, an additive for improving the properties of the resin film.

<Component (C)>
The component (C) is a photopolymerizable monomer having a polymerizable functional group (excluding the component (A)).
The term "polymerizable functional group" refers to a group that enables compounds to polymerize together by radical polymerization or the like, and is, for example, a group that contains a multiple bond between carbon atoms, such as an ethylenic double bond.
Examples of the polymerizable functional group include vinyl group, allyl group, acryloyl group, methacryloyl group, fluorovinyl group, difluorovinyl group, trifluorovinyl group, difluorotrifluoromethylvinyl group, trifluoroallyl group, perfluoroallyl group, trifluoromethylacryloyl group, nonylfluorobutylacryloyl group, vinyl ether group, fluorine-containing vinyl ether group, allyl ether group, fluorine-containing allyl ether group, styryl group, vinylnaphthyl group, fluorine-containing styryl group, fluorine-containing vinylnaphthyl group, norbornyl group, fluorine-containing norbornyl group, and silyl group. Among these, vinyl group, allyl group, acryloyl group, and methacryloyl group are preferred, and acryloyl group and methacryloyl group are more preferred.

Examples of photopolymerizable monomers having two polymerizable functional groups (bifunctional monomers) include trimethylolpropane di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, bis(hydroxymethyl)tricyclodecane di(meth)acrylate, etc.

Commercially available bifunctional monomers include, for example, Light Acrylate 3EG-A, 4EG-A, 9EG-A, NP-A, DCP-A, BP-4EAL, BP-4PA (all manufactured by Kyoeisha Chemical Co., Ltd.), A-NOD-N, APG-100 (all manufactured by Shin-Nakamura Chemical Co., Ltd.), ED-503 (manufactured by ADEKA Corporation), etc.

Examples of photopolymerizable compounds having three or more polymerizable functional groups include photopolymerizable siloxane compounds, photopolymerizable silsesquioxane compounds, and polyfunctional monomers having three or more polymerizable functional groups.

Examples of the photopolymerizable siloxane compound include compounds having an alkoxysilyl group and a polymerizable functional group in the molecule.
Commercially available examples of the photopolymerizable siloxane compound include those manufactured by Shin-Etsu Chemical Co., Ltd. under the product names "KR-513", "X-40-9296", "KR-511", "X-12-1048", and "X-12-1050".

Examples of the photopolymerizable silsesquioxane compound include compounds whose main chain skeleton consists of Si—O bonds and are represented by the following chemical formula: [(RSiO _3/2 ) _n ] (wherein R represents an organic group, and n represents a natural number).
R represents a monovalent organic group, and examples of the monovalent organic group include monovalent hydrocarbon groups which may have a substituent. Examples of the hydrocarbon group include aliphatic hydrocarbon groups and aromatic hydrocarbon groups. Examples of the aliphatic hydrocarbon group include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, nonyl, decyl, undecyl, and dodecyl groups, and alkyl groups having 1 to 12 carbon atoms are preferred.
Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, a benzyl group, a tolyl group, and a styryl group.
Examples of the substituent that the monovalent hydrocarbon group may have include a (meth)acryloyl group, a hydroxy group, a sulfanyl group, a carboxy group, an isocyanato group, an amino group, a ureido group, etc. In addition, the -CH ₂ - contained in the monovalent hydrocarbon group may be replaced by -O-, -S-, a carbonyl group, etc.
However, the photopolymerizable silsesquioxane compound has three or more polymerizable functional groups, such as vinyl groups, allyl groups, methacryloyl groups, and acryloyl groups.

The compound represented by the chemical formula: [(RSiO _3/2 ) _n ] may be any of a cage type, a ladder type, and a random type. The cage type silsesquioxane compound may be a complete cage type or an incomplete cage type in which the cage is partially open.
Commercially available photopolymerizable silsesquioxane compounds include, for example, products manufactured by Toagosei Co., Ltd. under the names "MAC-SQ LP-35,""MAC-SQTM-100,""MAC-SQSI-20," and "MAC-SQ HDM."

Examples of polyfunctional monomers having three or more polymerizable functional groups include ethoxylated (3) trimethylolpropane triacrylate, ethoxylated (3) trimethylolpropane trimethacrylate, ethoxylated (6) trimethylolpropane triacrylate, ethoxylated (9) trimethylolpropane triacrylate, ethoxylated (15) trimethylolpropane triacrylate, ethoxylated (20) trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, propoxylated (3) glyceryl triacrylate, propoxylated (3) glyceryl triacrylate, propoxylated (5.5) glyceryl triacrylate, propoxylated (3) trimethylolpropane triacrylate, propoxylated (6) trimethylolpropane triacrylate, trimethylolpropane triacrylate, trifunctional monomers such as 2-acryloxyethyl isocyanurate triacrylate, trimethylolpropane trimethacrylate, tris-(2-hydroxyethyl)-isocyanurate triacrylate, tris-(2-hydroxyethyl)-isocyanurate trimethacrylate, ε-caprolactone modified tris-(2-acryloxyethyl)isocyanurate, EO modified trimethylolpropane tri(meth)acrylate, PO modified trimethylolpropane tri(meth)acrylate, EO,PO modified trimethylolpropane tri(meth)acrylate; tetrafunctional monomers such as ditrimethylolpropane tetraacrylate, ethoxylated (4) pentaerythritol tetraacrylate, pentaerythritol tetra(meth)acrylate; and pentafunctional or higher monomers such as dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate.
Commercially available examples of the polyfunctional monomer include those manufactured by Shin-Nakamura Chemical Co., Ltd. under the product names "A-9300-1CL", "AD-TMP", "A-9550", and "A-DPH", those manufactured by Nippon Kayaku Co., Ltd. under the product name "KAYARAD DPHA", and those manufactured by Kyoeisha Chemical Co., Ltd. under the product name "Light Acrylate TMP-A".

In the photocurable composition according to the embodiment, the component (C) may be used either as a single type alone, or as a combination of two or more types.
The content of the (C) component is preferably 1 to 50 parts by mass, more preferably 3 to 40 parts by mass, and even more preferably 5 to 35 parts by mass, relative to 100 parts by mass in total of the (A) component, the (B) component, and the (C) component.
When the content of component (C) is equal to or greater than the lower limit of the above-mentioned preferred range, the reaction between components (A) and (B) can be appropriately controlled, and the viscosity of the photocurable composition can be adjusted, thereby improving the coatability of the photocurable composition. On the other hand, when the content of component (C) is equal to or less than the upper limit of the above-mentioned preferred range, the curability of the resin film formed using the photocurable composition can be controlled.

The photocurable composition of this embodiment described above contains components (A), (B), and (D). The -OH group of the carboxy group contained in component (A) reacts with component (B) at room temperature to form an ester bond. In addition, component (D) acts on the (meth)acryloyl group in component (A) when irradiated with light, and a polymerization reaction proceeds through a photoradical reaction. Therefore, when a resin film is formed using the photocurable composition of this embodiment, a three-dimensional bonding reaction occurs near the substrate interface, and it is presumed that the adhesion between the substrate and the cured resin film is enhanced.

Such photocurable compositions are useful as materials for forming fine patterns on substrates using imprint technology, and are particularly suitable for photoimprint lithography. In particular, they are advantageous in improving the adhesion of nanoimprint materials to cycloolefin polymer (COP) films, which are useful as substrates for liquid crystal displays and have the characteristics of high total light transmittance and low birefringence.

(Pattern Forming Method)
The pattern forming method of the second aspect of the present invention includes a step of forming a resin film on a substrate using the photocurable composition of the first aspect described above (hereinafter referred to as "step (i)"), a step of pressing a mold having a concave-convex pattern against the resin film to transfer the concave-convex pattern to the resin film (hereinafter referred to as "step (ii)"), a step of exposing the resin film to which the concave-convex pattern has been transferred while pressing the mold against the resin film to form a cured resin film (hereinafter referred to as "step (iii)"), and a step of peeling the mold from the cured resin film (hereinafter referred to as "step (iv)").

Figure 1 is a schematic diagram illustrating one embodiment of a pattern formation method.

[Step (i)]
In the step (i), a resin film is formed on a substrate using the photocurable composition of the first embodiment described above.
As shown in Fig. 1(A), the photocurable composition of the first embodiment described above is applied to a substrate 1 to form a resin film 2. In Fig. 1(A), a mold 3 is disposed above the resin film 2.

The substrate 1 can be selected according to various applications, and examples thereof include a substrate for electronic components, a substrate on which a predetermined wiring pattern is formed, etc. More specifically, examples thereof include substrates made of metals such as silicon, silicon nitride, copper, chromium, iron, and aluminum, and glass substrates, etc. Examples of materials for the wiring pattern include copper, aluminum, nickel, and gold.
The shape of the substrate 1 is not particularly limited, and may be a plate or a roll. The substrate 1 may be either light-transmitting or non-light-transmitting depending on the combination with the mold, etc.

Examples of a method for applying the photocurable composition to the substrate 1 include a spin coating method, a spray method, a roll coating method, and a rotary coating method. Since the resin film 2 functions as a mask in an etching process of the substrate 1 that may be performed thereafter, it is preferable that the film thickness when applied to the substrate 1 is uniform. From this point of view, when applying the photocurable composition to the substrate 1, a spin coating method is preferable.
The thickness of the resin film 2 may be appropriately selected depending on the application, and may be, for example, about 0.05 to 30 μm.

[Step (ii)]
In the step (ii), a mold having a concave-convex pattern is pressed against the resin film to transfer the concave-convex pattern to the resin film.
1B, a mold 3 having a fine uneven pattern on its surface is pressed against the substrate 1 on which the resin film 2 is formed, so as to face the resin film 2. This causes the resin film 2 to deform in accordance with the uneven structure of the mold 3.

The pressure applied to the resin film 2 when the mold 3 is pressed is preferably 10 MPa or less, more preferably 5 MPa or less, and particularly preferably 1 MPa or less.
By pressing the mold 3 against the resin film 2 , the photocurable composition located on the convex parts of the mold 3 is easily pushed aside to the concave parts of the mold 3 , and the concave-convex structure of the mold 3 is transferred to the resin film 2 .

The concave-convex pattern of the mold 3 can be formed according to a desired processing accuracy by, for example, photolithography or electron beam lithography.
The mold 3 is preferably a light-transmitting mold. The material of the light-transmitting mold is not particularly limited, but may be any material having a predetermined strength and durability. Specific examples include glass, quartz, light-transmitting resin films such as polymethyl methacrylate and polycarbonate resin, transparent metal deposition films, flexible films such as polydimethylsiloxane, photocured films, metal films, and the like.

[Step (iii)]
In the step (iii), the resin film to which the concave-convex pattern has been transferred is exposed to light while the mold is pressed against the resin film, thereby forming a cured resin film.
1C, the resin film 2 to which the concave-convex pattern has been transferred is exposed to light while the mold 3 is pressed against the resin film 2. Specifically, electromagnetic waves such as ultraviolet (UV) rays are irradiated onto the resin film 2. By exposure, the resin film 2 is cured while the mold 3 is pressed against it, and a cured resin film (cured resin pattern) to which the concave-convex pattern of the mold 3 has been transferred is formed.
The mold 3 in FIG. 1C is transparent to electromagnetic waves.

The light used to harden the resin film 2 is not particularly limited, and examples include light or radiation with wavelengths in the range of high-energy ionizing radiation, near ultraviolet light, far ultraviolet light, visible light, infrared light, etc. Examples of radiation that can be used include microwaves, EUV, LED, semiconductor laser light, or laser light used in semiconductor microfabrication, such as 248 nm KrF excimer laser light or 193 nm ArF excimer laser light. These lights may be monochrome light or may be light of multiple different wavelengths (mixed light).

[Step (iv)]
In the step (iv), the mold is peeled off from the cured resin film.
1(D), the mold 3 is peeled off from the cured resin film, whereby a pattern 2' (cured resin pattern) made of the cured resin film to which the concave-convex pattern has been transferred is patterned on the substrate 1.

In the pattern formation method of the present embodiment described above, a photocurable composition containing the above-mentioned components (A), (B), and (D) is used. Because such a photocurable composition is used, the adhesion between the substrate and the cured resin film is good.

In this embodiment, a release agent may be applied to a surface 31 of the mold 3 that comes into contact with the resin film 2 (FIG. 1A). This enhances the releasability between the mold and the cured resin film.
Examples of the release agent include silicon-based release agents, fluorine-based release agents, polyethylene-based release agents, polypropylene-based release agents, paraffin-based release agents, montan-based release agents, and carnauba-based release agents. Among these, fluorine-based release agents are preferred. For example, commercially available coating-type release agents such as Optool DSX manufactured by Daikin Industries, Ltd. can be suitably used. The release agents may be used alone or in combination of two or more.

In this embodiment, an organic layer may be provided between the substrate 1 and the resin film 2. This allows the substrate 1 to be etched using the resin film 2 and the organic layer as a mask, thereby allowing a desired pattern to be easily and reliably formed on the substrate 1. The thickness of the organic layer may be adjusted appropriately according to the depth to which the substrate 1 is processed (etched), and is preferably 0.02 to 2.0 μm, for example. The material of the organic layer is preferably one that has lower etching resistance to oxygen-based gases than the photocurable composition, and higher etching resistance to halogen-based gases than the substrate 1. The method for forming the organic layer is not particularly limited, but examples include sputtering and spin coating.

The pattern formation method of the second embodiment may further include other steps (optional steps) in addition to the steps (i) to (iv).
Examples of the optional steps include an etching step (step (v)) and a step of removing the cured resin film (cured resin pattern) after the etching treatment (step (vi)).

[Step (v)]
In step (v), for example, the substrate 1 is etched using the pattern 2' obtained in the above steps (i) to (iv) as a mask.
As shown in FIG. 2(E), the substrate 1 on which the pattern 2' is formed is irradiated with at least one of plasma and reactive ions (indicated by the arrows), so that the portion of the substrate 1 exposed on the side of the pattern 2' is etched away to a predetermined depth.
The plasma or reactive ion gas used in step (v) is not particularly limited as long as it is a gas commonly used in the field of dry etching.

[Step (vi)]
In the step (vi), the cured resin film remaining after the etching treatment in the step (v) is removed.
As shown in FIG. 2(F), this is a step of removing the cured resin film (pattern 2') remaining on the substrate 1 after the etching process of the substrate 1.
The method for removing the cured resin film (pattern 2') remaining on the substrate 1 is not particularly limited, but may be, for example, a treatment for cleaning the substrate 1 with a solution that dissolves the cured resin film.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

<Preparation of Photocurable Composition>
The components shown in Tables 1 to 10 were mixed to prepare photocurable compositions of each example.

In Tables 1 to 10, the abbreviations have the following meanings. The numbers in brackets [ ] are the amounts blended (parts by mass). The amounts of each component other than component (D) represent the relative proportions to the total of 100 parts by mass of each component other than component (D).

Component (A) (carboxy-containing (meth)acrylate)
(A)-1: Monohydroxyethyl phthalate acrylate, manufactured by Toagosei Co., Ltd., product name “Aronix M-5400”.
(A)-2: 2-acryloyloxyethyl-succinic acid, manufactured by Kyoeisha Chemical Co., Ltd., product name "HOA-MS".
(A)-3: 2-acryloyloxyethylhexahydrophthalic acid, manufactured by Kyoeisha Chemical Co., Ltd., product name "HOA-HH".
(A)-4: 2-methacryloyloxyethyl phthalate, manufactured by Shin-Nakamura Chemical Co., Ltd., product name “NK Ester CB-1”.

Component (Z) (non-carboxy-containing (meth)acrylate)
(Z)-1: 3-ethyl-3-hydroxymethyloxetane, manufactured by Toagosei Co., Ltd., product name “OXT-101”.
(Z)-2: xylylene bisoxetane, manufactured by Toagosei Co., Ltd., product name “OXT-121”.
(Z)-3: (3-ethyloxetan-3-yl)methyl acrylate, manufactured by Osaka Organic Chemical Industry Ltd., product name "OXE-10".
(Z)-4: Dipentaerythritol pentahexaacrylate, manufactured by Nippon Kayaku Co., Ltd., product name “KAYARAD DPHA”.
(Z)-5: Diglycerin EO-modified acrylate, manufactured by Toagosei Co., Ltd., product name “Aronix M-460”.

Component (B) (acid anhydride)
(B)-1: Methacrylic anhydride, manufactured by Tokyo Chemical Industry Co., Ltd.
(B)-2: Phthalic anhydride, manufactured by Tokyo Chemical Industry Co., Ltd.
(B)-3: Tetrahydrophthalic anhydride, manufactured by Tokyo Chemical Industry Co., Ltd.
(B)-4: Hexahydrophthalic anhydride, manufactured by Tokyo Chemical Industry Co., Ltd.
(B)-5: Maleic anhydride, manufactured by Tokyo Chemical Industry Co., Ltd.

Component (S) (Silane coupling agent)
(S)-1: Product name "KBM-503" manufactured by Shin-Etsu Silicones Co., Ltd.
(S)-2: Product name "KBE-503" manufactured by Shin-Etsu Silicones Co., Ltd.
(S)-3: Product name "KBM-502" manufactured by Shin-Etsu Silicones Co., Ltd.
(S)-4: Product name "KBM-403" manufactured by Shin-Etsu Silicones Co., Ltd.
(S)-5: Product name "KBE-403" manufactured by Shin-Etsu Silicones Co., Ltd.

Component (C) (photopolymerizable monomer)
(C)-1: Isobornyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd., product name “Light Ester IB-X”.
(C)-2: Isobornyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd., product name “Light Acrylate IB-XA”.
(C)-3: Tetrahydrofurfuryl acrylate, manufactured by Kyoeisha Chemical Co., Ltd., product name "Light Acrylate THF-A".
(C)-4: Benzyl acrylate, manufactured by Hitachi Chemical Co., Ltd., product name “FA-BZA”.
(C)-5: Glycidyl tolyl ether, manufactured by ADEKA Corporation, product name "ADEKA Glycirol ED-529".
(C)-6: 1,9-Nonanediol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., product name "A-NOD-N".
(C)-7: Dipropylene glycol diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., product name “APG-100”.
(C)-8: Neopentyl glycol diacrylate, manufactured by Kyoeisha Chemical Co., Ltd., product name "Light Acrylate NP-A".
(C)-9: 1,6-bis(oxiran-2-ylmethoxy)hexane, manufactured by ADEKA Corporation, product name "ADEKA GLYCILOR ED-503".
(C)-10: Trimethylolpropane triacrylate, manufactured by Kyoeisha Chemical Co., Ltd., product name "Light Acrylate TMP-A".

Component (D) (photopolymerization initiator)
(D)-1: Hydroxycyclohexyl phenyl ketone, manufactured by IGM Resins B.V., product name "Omnirad 184".

<Evaluation>
For each example of the photocurable composition, the adhesion between the substrate and the cured resin film was evaluated by the methods shown below. The results are shown in Tables 1 to 10.

[Adhesion between substrate and cured resin film]
Each of the photocurable compositions of the examples was applied onto the cycloolefin polymer film using the inkjet coating device to form a resin film with a thickness of 200 nm.
Next, the resin film having a thickness of 200 nm was cured by exposing the entire surface to light from an i-line light source at an exposure dose of 1000 mJ/cm ² to obtain a cured resin film.
Thereafter, the adhesion between the substrate and the cured resin film thus obtained was evaluated by the method described below.

The adhesion between the substrate and the cured resin film was evaluated by a cross-cut cellophane tape peeling test according to JIS K5400 and based on the following criteria.
Evaluation criteria: Number of unpeeled squares/100 squares
Good: 80/100 or more Bad: less than 80/100

The results in Tables 1 to 10 confirm that the photocurable compositions of Examples 1 to 69 to which the present invention was applied exhibited good adhesion between the substrate and the cured resin film.

1. Substrate, 2. Resin film, 3. Mold

Claims (8)

Component (A): a carboxyl group-containing (meth)acrylate represented by the following general formula (A1-3) ,
Component (B): an acid anhydride,
Component (D): a photopolymerization initiator,
A photocurable composition comprising:

[In the formula, R ¹³ represents a hydrogen atom or a methyl group, R ²³ represents a linear or branched alkylene group having 1 to 4 carbon atoms, and R ³³ represents a group in which two hydrogen atoms have been removed from benzene.] The photocurable composition according to claim 1, wherein the component (B) is an acid anhydride having a photocurable polar group. The photocurable composition according to claim 1 or 2, further comprising component (C): a photopolymerizable monomer having two or more polymerizable functional groups. The resist composition according to claim 3, wherein the component (C) contains at least one photopolymerizable monomer selected from the group consisting of trimethylolpropane di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and bis(hydroxymethyl)tricyclodecane di(meth)acrylate. 5. The photocurable composition according to claim 3, comprising 40 to 90 parts by mass of the component (A), 1 to 50 parts by mass of the component (B), and 1 to 50 parts by mass of the component (C) relative to a total of 100 parts by mass of the component (A), the component ( B ), and the component (C). The photocurable composition according to any one of claims 3 to 5 , wherein the component (C) is a photopolymerizable monomer having two or three polymerizable functional groups. The photocurable composition according to any one of claims 1 to 6 , which is used for photoimprint lithography. A step of forming a resin film on a substrate using the photocurable composition according to any one of claims 1 to 7 ;
a step of pressing a mold having a concave-convex pattern against the resin film to transfer the concave-convex pattern to the resin film;
a step of exposing the resin film to light while pressing the mold against the resin film, to thereby form a cured resin film;
peeling the mold from the cured resin film;
The pattern forming method comprises the steps of:

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