JP6084055B2 - Pattern formation method by imprint - Google Patents

Description

  The present invention relates to a pattern forming method by imprinting.

  Lithography technology is a core technology in various microfabrication processes represented by semiconductor device processes, and representatively, lithography technology using a photoresist composition is widely used. When microfabrication is performed using a photoresist composition, the photoresist composition is generally applied to a substrate or the like and the photoresist film is selectively exposed, and then the exposed photoresist film is developed with a developer. To develop a photoresist pattern.

  As another lithography technique using a photoresist composition, a photocurable film forming composition is applied on a substrate to form a coating film, and then a mold having a concavo-convex structure is pressed against the coating film to deform it. The “photoimprint lithography method” is known in which a deformed coating film is exposed and cured. The optical imprint lithography method is widely used because it has a merit that development is unnecessary.

  As such a photoimprint lithography method, for example, photocuring containing a siloxane polymer (A) having a polymerizable group that is polymerized by light irradiation, an alkoxysilane compound (B), and a polymerization initiator (C). A method using a conductive film forming composition is known (see Patent Document 1).

JP 2011-023698 A

  However, when a pattern is formed by a photoimprint lithography method using a photocurable film forming composition as described in Patent Document 1, a pattern in which the depth of the recess in the pattern is on the order of nm is good. Even if a pattern with a simple shape can be formed, a pattern in which the depth of the concave portion in the pattern is on the order of μm and the depth of the concave portion is smaller than the width of the convex portion is formed without causing a pattern defect. Difficult to do. When forming the pattern of the latter shape using the photocurable film forming composition as described in Patent Document 1, a part of the convex portion is firmly attached to the mold, so that the mold is peeled from the pattern. At this time, the convex portion is broken or a part of the pattern is peeled off from the substrate.

  The present invention has been made in view of the above problems, and a pattern in which the depth of the concave portion in the pattern is on the order of μm and the depth of the concave portion is smaller than the width of the convex portion by an optical imprint lithography method. It is an object of the present invention to provide a pattern forming method by imprinting that can suppress the folding of a convex part and peeling of a pattern from a substrate when the mold is peeled from the pattern.

  The present inventors form a concavo-convex pattern in which the depth of the concave portion is 1.0 to 5.0 μm and the ratio D / W of the concave portion depth (D) to the convex portion width (W) is 1 or more. In the state where the coating film is deformed by pressing the mold against the coating film made of the photocurable film-forming composition for imprinting, the coating film is exposed to an exposure amount of 0.3 required for complete curing of the coating film. After exposure at an exposure amount of ˜25%, the present inventors have found that the above problems can be solved by peeling the mold from the exposed coating film, and have completed the present invention.

The present invention comprises a coating film forming step of applying a photocurable film forming composition for imprinting onto a substrate;
A deformation process in which the mold is pressed against the coating film to deform the coating film; and
A first exposure step of exposing the coating film while pressing the mold against the coating film;
Including a mold peeling step for peeling the mold from the coating film on which the concavo-convex pattern is formed after the first exposure step,
The exposure amount in the first exposure step is 0.3 to 25% of the exposure amount required for complete curing of the coating film,
Pattern formation by imprinting in which the depth of the concave portion in the concave / convex pattern is 1.0 to 5.0 μm and the ratio D / W of the concave portion depth (D) to the convex portion width (W) is 1 or more Is the method.

  According to the present invention, when forming a pattern in which the depth of the concave portion in the pattern is on the order of μm and the depth of the concave portion is smaller than the width of the convex portion by the optical imprint lithography method, the mold is removed from the pattern. It is possible to provide a pattern forming method by imprinting that can suppress the folding of the convex part and the peeling of the pattern from the substrate during peeling.

It is a figure which shows the outline of the pattern formation method which concerns on this invention.

The pattern forming method by imprinting according to the present invention includes:
A coating film forming step of applying a photocurable film forming composition for imprinting onto a substrate; and
A deformation process in which the mold is pressed against the coating film to deform the coating film; and
A first exposure step of exposing the coating film in a state where the mold is pressed against the coating film;
A mold peeling step of peeling the mold from the coating film on which the concavo-convex pattern is formed after the first exposure step.
Moreover, in the pattern formation method by the imprint which concerns on this invention, the exposure amount in a 1st exposure process is 0.3 to 25% of the exposure amount required for complete hardening of a coating film.
Furthermore, in the concavo-convex pattern formed by the imprint pattern forming method according to the present invention, the depth of the concave portion in the concavo-convex pattern is 1.0 to 5.0 μm, The ratio D / W to the width (W) is 1 or more.

  Hereafter, each process which the pattern formation method by the imprint which concerns on this invention contains is demonstrated in order.

≪Coating film formation process≫
As shown in FIGS. 1 (a) and 1 (b), in the coating film forming step, a photocurable film forming composition for imprinting is applied onto the substrate 1 to form the coating film 2 on the substrate. To do. Hereinafter, the photocurable film forming composition, the substrate, and the coating method of the photocurable film forming composition will be described in order.

[Photocurable film-forming composition]
The photocurable film-forming composition for imprinting is not particularly limited as long as it is a photocurable composition that can form a film having a hardness that can be imprinted by coating. A photocurable film forming composition can be suitably selected from the photocurable film forming compositions conventionally used for the photoimprint method.

  Among the photocurable film-forming compositions, suitable are those containing a resin having a photopolymerizable functional group such as a functional group containing an ethylenically unsaturated bond and a photopolymerization initiator. The photocurable film-forming composition may contain a solvent for the purpose of improving coatability.

  As the resin having a photopolymerizable functional group, a siloxane resin having a photopolymerizable functional group is preferable because a coating film having a desired film thickness can be easily formed and the curability is excellent. When the photocurable film forming composition contains a siloxane resin having a photopolymerizable functional group, the photocurable film forming composition may contain an alkoxysilane compound. Hereinafter, a siloxane resin having a photopolymerizable functional group, an alkoxysilane compound, a photopolymerization initiator, and a solvent that are suitable resins for the components of the photocurable film-forming composition will be described in order.

(Siloxane resin having a photopolymerizable functional group)
The siloxane resin having a photopolymerizable functional group (hereinafter also referred to as siloxane resin) is not particularly limited as long as it is a resin having a siloxane skeleton and has a photopolymerizable functional group. Preferable examples of the siloxane resin (A) having a photopolymerizable functional group include siloxane resins represented by the following general formula (A1).

（式（Ａ１）中、Ｒ^１は、エチレン性不飽和二重結合を含有する基である。Ｒ^０は、単結合又は炭素数１〜９のアルキレン基である。式（Ａ１）で表される樹脂中、複数のＲ^０は同一であっても異なっていてもよい。Ｒ^２はアルキル基、アリール基、又は水素原子である。式（Ａ１）で表される樹脂中、複数のＲ^２は同一であっても異なっていてもよい。ｍ：ｎは５０：５０〜１００：０（モル比）の範囲である。）

(In Formula (A1), R ¹ is a group containing an ethylenically unsaturated double bond. R ⁰ is a single bond or an alkylene group having 1 to 9 carbon atoms. Represented by Formula (A1) In the resin, a plurality of R ⁰ may be the same or different, R ² is an alkyl group, an aryl group, or a hydrogen atom, and in the resin represented by the formula (A1), a plurality of R ² May be the same or different, and m: n is in the range of 50:50 to 100: 0 (molar ratio).)

In the formula (A1), the group containing an ethylenically unsaturated double bond in R ¹ is preferably one having an ethylenically unsaturated double bond at the terminal. Specific examples of suitable groups having an ethylenically unsaturated double bond at the terminal include vinyl group, allyl group, vinyloxy group, allyloxy group, acryloyloxy group, and methacryloyloxy group. Among these groups, an acryloyloxy group or a methacryloyloxy group is more preferable.

In formula (A1), examples of the alkylene group having 1 to 9 carbon atoms in R ⁰ include a linear or branched alkylene group. Preferably it is a C1-C7, More preferably, it is a C1-C5 linear alkylene group, Most preferably, they are a methylene group, ethylene group, and n-propylene group.

In formula (A1), examples of the alkyl group for R ² include an alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. A linear alkyl group such as a group, nonyl group, decyl group; 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1 -Branched alkyl groups such as ethylbutyl group, 2-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group; cyclopentyl group, cyclohexyl group, adamantyl group, And cyclic alkyl groups such as a norbornyl group, an isobornyl group, and a tricyclodecanyl group. Preferably it is a C1-C5 alkyl group, More preferably, it is a C1-C3 alkyl group, Most preferably, it is a methyl group.

Part or all of the hydrogen atoms contained in the alkyl group represented by R ² may be substituted with a halogen atom. Examples of the halogen atom include a chlorine atom, a bromine atom, and a fluorine atom, and a fluorine atom is most preferable from the viewpoint of mold releasability.

In formula (A1), examples of the aryl group in R ² include a phenyl group, a biphenylyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Of the aryl groups, a phenyl group is preferred. Further, the aryl group of R ² may have a substituent such as an alkyl group.

  In formula (A1), m: n (molar ratio) may be appropriately set in consideration of Si content, film thickness adjustment, and pressing pressure adjustment. m: n is preferably in the range of 50:50 to 99: 1, more preferably in the range of 70:30 to 99: 1, still more preferably in the range of 80:20 to 99: 1, and 90:10 to 99: 1. The range of is particularly preferable. As the ratio of m increases, the curability of the siloxane resin represented by the formula (A1) tends to increase.

  As the siloxane resin represented by the formula (A1), a resin represented by the following formula (A1-1) or (A1-2) is particularly preferable.

  In formula (A1-1) and formula (A1-2), Ra is a methyl group or a hydrogen atom. m and n are the same as m and n in the above formula (A1).

  The mass average molecular weight of the siloxane resin is not particularly limited, but is preferably 500 to 10,000, more preferably 1000 to 5000, and still more preferably 1000 to 3000. By making the mass average molecular weight of the siloxane resin within the above range, it is easy to achieve both an improvement in the effect of reducing the pressing force and an improvement in the characteristics of the pattern shape to be formed.

(Alkoxysilane compound)
When the photocurable film forming composition contains a siloxane resin having a photopolymerizable functional group, the photocurable film forming composition may contain an alkoxysilane compound. The alkoxysilane compound is a silane compound containing an alkoxy group (RO—) in which an alkyl group R is bonded to an oxygen atom. Preferable examples of the alkoxysilane compound include any compounds represented by the following formulas (B1) to (B3).

In the formula (B1), s + t = 4, and t is an integer of 1 to 4. In formula (B1), R ³ and R ⁴ are each independently an alkyl group. In formula (B1), the alkyl group in R ³ and R ⁴ is an alkyl group having 1 to 10 carbon atoms, and examples thereof are the same as those described above. The alkyl group in R ³ and R ⁴ is preferably a methyl group, an ethyl group, and a propyl group. In formula (B1), t is preferably an integer of 2 to 4.

  As an alkoxysilane compound represented by the formula (B1), it is easy to obtain a photocurable film-forming composition having excellent curability and stability. Therefore, ethyl-tri-n-propoxysilane, tetra-n-propoxysilane, tetra Ethoxysilane is preferred.

In formula (B2), R ^{5 to} R ⁷ are each independently an alkyl group or an alkoxy group, and at least one of R ^{5 to} R ⁷ is an alkoxy group. X is a single bond or an alkylene group having 1 to 5 carbon atoms.

In formula (B2), the alkyl group in R ^{5 to} R ⁷ is an alkyl group having 1 to 10 carbon atoms, and examples thereof are the same as those described above. A methyl group, an ethyl group, and a propyl group are preferable. In formula (B2), examples of the alkoxy group represented by R ^{5 to} R ⁷ include those represented by the formula —O—R ^B2 [R ^B2 is an alkyl group having 1 to 5 carbon atoms]. The alkyl group for R ^{B2 is} the same as described above. A methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group are preferable. In the formula (B2), the number of alkoxy groups in R ^{5 to} R ⁷ is preferably 2 or more, more preferably 2 to 6. In formula (B2), examples of the alkylene group having 1 to 5 carbon atoms in X include a methylene group, an ethylene group, an n-propylene group, a tetramethylene group, and a pentamethylene group. In the formula (B2), X is preferably a single bond or an ethylene group.

  As the alkoxysilane compound represented by the formula (B2), since it is easy to obtain a photocurable film-forming composition having excellent curability and stability, the following formulas (B2-1) to (B2-4) and ( Those represented by B3) are preferred.

In formula (B3), R ^{8 to} R ⁹ are each independently an alkyl group or an alkoxy group, and at least one of R ^{8 to} R ⁹ is an alkoxy group. Wherein ^(B3), the alkyl group in R 8 to R ⁹ include those similar to the above is an alkyl group having 1 to 10 carbon atoms. Preferably it is a C1-C6 alkyl group, Most preferably, it is a methyl group. In formula (B3), examples of the alkoxy group for R ^{8 to} R ⁹ include those represented by the formula —O—R ^B3 [R ^B3 is the same as R ^B2 above]. Preferably, it is an n-butoxy group. In the formula (B3), the number of alkoxy groups in R ^{8 to} R ⁹ is preferably 2 to 8, and particularly preferably 4. As the alkoxysilane compound represented by the formula (B3), a compound represented by the following formula is particularly preferable because a photocurable film-forming composition having excellent curability and stability can be easily obtained.

  The photocurable film forming composition is exposed by adding an alkoxysilane compound represented by the above formulas (B1) to (B3) together with a siloxane resin having a photopolymerizable functional group to the photocurable film forming composition. In this case, the curability of the photocurable film-forming composition can be improved.

(Polymerization initiator)
The polymerization initiator is not particularly limited as long as it is a compound that initiates and accelerates photopolymerization of components contained in the photocurable film-forming composition when exposing the photocurable film-forming composition. Specific examples of the polymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 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- (methylthio) phenyl] -2 -Morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, ethanone- -[9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (o-acetyloxime), 2,4,6-trimethylbenzoyldiphenylphosphine 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, benzyldimethyl ketal, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, methyl o-benzoylbenzoate, 2 , 4-Diethylthioxanthone, 2-chlorothioxanthate 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-mercaptobenzoimidar, 2-mercaptobenzoxazole, 2-mercaptobenzo Thiazole, 2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) -imidazolyl dimer, benzophenone, 2-chlorobenzophenone, p, p'-bisdimethylaminobenzophenone, , 4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, 3,3-dimethyl-4-methoxybenzophenone, benzyl, 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, p- tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, α, α-dichloro-4-phenoxy Cyacetophenone, 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-diethi Amino-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; methyl ethyl ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide Ketone peroxides such as oxides; Diacyl peroxides such as isobutyryl peroxide and bis (3,5,5-trimethylhexanoyl) peroxide; p-menthane hydroperoxide, 1,1,3,3-tetra Hydroperoxides such as methylbutyl hydroperoxide; Dialkyl peroxides such as 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane; 1,1-bis (t-butylperoxy) -3,3,5-trimethyl Peroxyketals such as cyclohexane; peroxyesters such as t-butyl peroxyneodecanoate and 1,1,3,3-tetramethylperoxyneodecanoate; di-n-propyl peroxydicarbonate, Peroxydicarbonates such as diisopropylperoxydicarbonate; azo compounds such as azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyrate And the like.

  Among the above, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1- [4- (2-Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one Alkylphenone polymerization initiators such as 1-hydroxy-cyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-phenyl-propan-1-one are particularly preferable because of excellent balance between polymerization rate and curing ability.

  As the polymerization initiator, for example, commercially available products such as IRGACURE 907, IRGACURE 369, IRGACURE 651, and IRGACURE 184 (all manufactured by Ciba Specialty Chemicals) can be used. Any one of these polymerization initiators may be used alone, or two or more thereof may be used in combination.

  The content of the polymerization initiator in the photopolymerizable film forming composition is not particularly limited as long as the curing of the photopolymerizable film forming composition proceeds well. When the photopolymerizable film-forming composition contains a resin having a photopolymerizable functional group, the amount of the polymerization initiator is 0.01 to 2.0 with respect to 100 parts by mass of the resin having a photopolymerizable functional group. A mass part is preferable and 0.02-1.5 mass part is more preferable.

  The photopolymerizable film-forming composition may contain a solvent for the purpose of improving coating properties. Suitable examples of the solvent that may be contained in the photopolymerizable film-forming composition include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-pentyl alcohol, s-pentyl alcohol, t-pentyl alcohol, and isopentyl. Alcohol, isobutanol, 2-ethylbutanol, neopentyl alcohol, n-butanol, s-butanol, t-butanol, 1-propanol, n-hexanol, 2-heptanol, 3-heptanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 4-methyl-2-pentanol, 1-butoxy-2-propanol, propylene glycol monopropyl ether, 5-methyl-1-hexanol, 6-methyl-2-heptanol, 1-octanol 2-octanol Chain-structured alcohols such as 3-octanol, 4-octanol, 2-ethyl-1-hexanol, 2- (2-butoxyethoxy) ethanol; cyclopentanemethanol, 1-cyclopentylethanol, cyclohexanol, cyclohexanemethanol, cyclohexane Alcohols having a cyclic structure such as ethanol, 1,2,3,6-tetrahydrobenzyl alcohol, exo-norbornol, 2-methylcyclohexanol, cycloheptanol, 3,5-dimethylcyclohexanol, benzyl alcohol, terpionol Ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, methyl isoamyl ketone, 1,1,1-trimethylacetone; ethylene glycol, ethyl Polyhydric alcohols such as lenglycol monoacetate, diethylene glycol or diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, or monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof; And cyclic ethers such as ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, and ethyl 3-ethoxypropionate. These may be used alone or in combination of two or more.

  When the photopolymerizable film-forming composition contains a solvent, the content of the solvent is not particularly limited as long as a coating film having a desired film thickness can be formed. When the photopolymerizable film-forming composition contains a solvent, the solid content concentration of the photopolymerizable film-forming composition is preferably 20% by mass or more, and more preferably 30% by mass or more.

〔substrate〕
The material of the substrate on which the photopolymerizable film-forming composition is applied is appropriately selected from various materials in consideration of adhesion with the coating film. Suitable materials for the substrate include quartz, sapphire, Si and the like.

[Method of applying photocurable film-forming composition]
The method for applying the photocurable film-forming composition onto the substrate 1 is not particularly limited, and can be appropriately selected from coating film forming methods employed in various imprinting methods. Specific examples of the method for applying the photocurable film-forming composition on the substrate include spin coating, spraying, roll coating, and spin coating.

  In the pattern forming method according to the present invention, the coating film 2 is deformed by the mold 3 so that the depth of the concave portion is 1.0 to 5.0 μm, more effectively 1.0 to 3.0 μm. Form. The thickness of the coating film 2 formed on the substrate 1 is not particularly limited as long as it can form a pattern having a predetermined depth in such a range.

≪Deformation process≫
As shown in FIG. 1C and FIG. 1D, in the deformation process, the mold 3 is pressed from above the coating film 2 against the coating film 2 formed on the substrate 1 to thereby apply the coating film 2. Deform. In the pattern forming method according to the present invention, the depth of the concave portion is 1.0 to 5.0 μm, and the ratio D / W of the concave portion depth (D) to the convex portion width (W) is 1 or more. A pattern is formed. In the case of forming a pattern having such a shape, when the mold 3 is peeled from the deformed coating film 2, the projections are easily bent or the pattern is peeled off from the substrate. According to this, it is possible to form a pattern having a good shape while suppressing such problems.

  The shape of the pattern is not particularly limited and is selected from various patterns. Examples of the shape of the pattern formed by pressing the mold 3 include a dot pattern in which columnar convex portions such as a prismatic shape and a cylindrical shape are arranged, a line and space pattern, a lattice pattern, and the like.

≪First exposure process≫
As shown in FIG. 1 (e), in the first exposure step, the deformed coating film 2 is irradiated with electromagnetic waves such as ultraviolet rays (UV) in a state where the mold 3 is pressed against the coating film 2. The coating film 2 is exposed and cured. For this reason, it is necessary for electromagnetic waves to permeate the mold 3, and the mold 3 is formed using a material that transmits the irradiated electromagnetic waves. Examples of the material of the mold 3 include quartz and PDMS.

  The exposure in the first exposure step is performed with an exposure amount of 0.3 to 25% of the exposure amount required for complete curing of the coating film 2. Here, the complete curing of the coating film 2 is cured when the surface of the coating film 2 is scanned with a stylus pressure of 1 mgf using a stylus type surface shape measuring device (Dektak150, manufactured by ULVAC, Inc.). A state in which the coating film 2 is not damaged.

  If the exposure amount in the first exposure step is too small relative to the exposure amount required for complete curing of the coating film 2, the curing of the coating film 2 hardly progresses, so that the mold 3 is peeled from the coating film 2 in the next step. In some cases, a pattern formed by deforming the coating film cannot maintain a desired shape. When the exposure amount in the first exposure step is excessive with respect to the exposure amount required for complete curing of the coating film 2, when the mold 3 is peeled from the coating film 2 having the concavo-convex pattern, the coating film having the concavo-convex pattern 2 may be peeled off from the substrate 1 or the convex portion of the concave-convex pattern may be broken. The exposure amount in the first exposure step can be adjusted by a method for adjusting the exposure time or a method for adjusting the amount of energy per unit time emitted from the light source used for exposure.

≪Mold peeling process≫
As shown in FIGS. 1E and 1F, in the mold peeling step, the mold 3 is peeled from the coating film 2 on which the concave / convex pattern is formed. Since the coating film 2 is exposed at an exposure amount of 0.3 to 25% of the exposure amount required for complete curing, even if the mold 3 is peeled from the coating film 2 having the concavo-convex pattern, the coating film having the concavo-convex pattern It is possible to form a pattern with a good shape on the substrate while suppressing the peeling of the second substrate 1 from the substrate 1 and the breakage of the convex portions of the concave-convex pattern.

  The pattern composed of the cured coating film 2 after the mold 3 is peeled off is incomplete but is exposed to some extent, and is thus cured to some extent. For this reason, the pattern formed of the cured coating film 2 from which the mold 3 has been peeled may be used as it is in the next process. Moreover, after the pattern which consists of the hardened coating film 2 is exposed again in the 2nd exposure process mentioned later as needed, and also advances hardening, it may be used for the process of the following process.

≪Second exposure process≫
As shown in FIG. 1 (g) and FIG. 1 (h), the cured coating film 2 from which the mold 3 has been peeled in the mold peeling step may be further exposed in the second exposure step. The exposure method in the second exposure step is the same as that in the first exposure step except that the coating film 2 is directly exposed without using the mold 3. In the second exposure step, the coating film 2 may or may not be completely cured, and an exposure amount is appropriately selected so that the coating film 2 is cured to a desired level. However, it is preferable that the deformed coating film is completely cured, and the sum of the exposure amount in the first exposure step and the exposure amount in the second exposure step is equal to or greater than the exposure amount required for complete curing of the coating film. Is preferred.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

[Preparation Example 1]
A siloxane resin, propylene glycol-1-methyl ether-2-acetate (PGMEA), and a polymerization initiator of the type shown in Table 1 are uniformly mixed in the composition shown in Table 1 to form a photopolymerizable film-forming composition. Products PPC1 to PPC4 were obtained.

As the siloxane resin, a resin represented by the following formula (A1-2), in which Ra is a methyl group and m: n is 90:10 (mass average molecular weight: 2300) was used.

The following PI1 and PI2 were used as polymerization initiators.
PI1: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one PI2: 1-hydroxy-cyclohexyl phenyl ketone

(Confirmation of exposure time required for complete curing)
For the obtained photopolymerizable film forming compositions PPC1 to PPC4, the exposure time required for complete curing under a certain exposure energy condition was measured as an index of the exposure amount required for complete curing. The photopolymerizable film forming compositions PPC1 to PPC4 were applied to a Si substrate using a spin coater (MS-A200, manufactured by Mikasa Co., Ltd.) to form a coating film having a thickness of 0.9 μm. The formed coating film was exposed using a nanoimprinter (ST200, manufactured by Toshiba Machine Co., Ltd.) with an exposure energy of 33 mW / cm ² and appropriately changing the exposure time in units of 1 second. . It was determined whether or not the coating film exposed at various exposure times was completely cured by a test using a stylus type surface shape measuring instrument (Dektak 150, manufactured by ULVAC, Inc.). When the surface of the coating film 2 was scanned with a stylus pressure of 1 mgf, the cured coating film was judged to be completely cured when it was not scratched, and the scratched state was judged to be incomplete curing. Thus, the shortest exposure time which can fully harden a coating film was calculated | required. The exposure time required for complete curing of the coating film was 4 seconds for PPC1, 25 seconds for PPC2, 300 seconds for PPC3, and 30 seconds for PPC4.

[Examples 1 to 11 and Comparative Examples 1 to 4]
A photopolymerizable film-forming composition of the type shown in Table 1 was applied onto a Si substrate using a spin coater (MS-A200, manufactured by Mikasa Corporation) to form a coating film having a thickness of 0.9 μm. . The formed coating film was pressed with a mold having a recess having an inner diameter of 2 μm and a depth of 2.4 μm to deform the coating film, thereby forming a pattern having a plurality of cylindrical convex portions having a diameter of 2 μm and a height of 2.4 μm. . In a state where the mold was pressed against the deformed coating film, the coating film was exposed at an exposure energy of 33 mW / cm ² for a time shown in Table 2 using a nanoimprinter (ST200, manufactured by Toshiba Machine Co., Ltd.). After the exposure, the mold was peeled off from the coating film, and the shape of the formed pattern was observed with a scanning electron microscope (SEM). From the observation result by SEM, the shape of the formed pattern was evaluated according to the following criteria. Table 2 shows the evaluation results of the pattern shape.
(Double-circle): The bending of a convex part and peeling from the board | substrate of a pattern are not observed.
◯: Slight breakage of the convex portion and peeling of the pattern from the substrate are observed.
X: Generation | occurrence | production of the bending of a convex part and peeling from the board | substrate of a pattern is remarkable.

  According to Examples 1 to 11, when a pattern including a plurality of cylindrical convex portions having a diameter of 2 μm and a height of 2.4 μm is formed by imprinting using the photopolymerizable film forming composition, the mold is pressed. After the coating film in a deformed state is exposed with an exposure amount of 0.3 to 25% of the exposure amount necessary for complete curing of the coating film, the mold is peeled off from the coating film, so that the protrusions in the pattern are bent. It can also be seen that peeling of the pattern from the substrate can be suppressed.

  On the other hand, according to Comparative Examples 1 to 4, when the coating film in a state where the mold is pressed and deformed is exposed with an exposure amount exceeding 25% of the exposure amount necessary for complete curing of the coating film, the mold is peeled off from the coating film. It can be seen that the occurrence of breakage of the protrusions in the pattern and the peeling of the pattern from the substrate during the patterning.

1 Substrate 2 Coating film 3 Mold

Claims (6)

A coating film forming step of applying a photocurable film-forming composition for imprinting onto a semiconductor substrate; and
A deformation step of deforming the coating film by pressing a mold against the coating film;
Exposing the coating film in a state in which the mold is pressed against the coating film, a first exposure step;
A mold peeling step for peeling the mold from the coating film on which the concave / convex pattern is formed after the first exposure step,
The exposure amount in the first exposure step is 0.3 to 25% of the exposure amount required for complete curing of the coating film,
A pattern by imprinting in which the depth of the concave portion in the concave / convex pattern is 1.0 to 5.0 μm and the ratio D / W of the concave portion depth (D) to the convex portion width (W) is 1 or more. Forming method.   The pattern formation method by imprint of Claim 1 whose said imprint is an imprint for semiconductor substrate pattern formation.   The pattern forming method by imprinting according to claim 1 or 2, wherein, in the first exposure step, the coating film is exposed through the mold in a state where the mold is pressed against the coating film. The pattern formation method by imprint of any one of Claims 1-3 including the 2nd exposure process which further exposes the said coating film in which the said uneven | corrugated pattern was formed after the mold peeling process. The pattern formation method by imprint of Claim 4 whose sum total of the exposure amount in said 1st exposure process and said 2nd exposure process is more than the exposure amount required for the complete hardening of the said coating film. The pattern formation method by imprint of any one of Claims 1-5 in which the said photocurable film formation composition contains the siloxane resin which has a photopolymerizable functional group.

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