Pattern formation method and article manufacturing method

Abstract

This invention provides new technologies for pattern formation methods and article manufacturing methods. [Solution] A pattern forming method is provided for forming a pattern of a curable composition on a substrate. The thickness of the residual film sandwiched between the most convex part of the mold's irregularities and the substrate is set to 50 nm or more, and the height difference of the mold's irregularities is set to be less than or equal to the thickness of the residual film. The pattern forming method includes a forming step of forming an inversion layer on the irregularities transferred from the mold onto the cured film, a removal step of removing the upper part of the inversion layer so as to expose the top surface of the convex part of the irregularities formed on the cured film with the inversion layer embedded in the recesses of the irregularities formed on the cured film, and an etching step of using the inversion layer embedded in the recesses as a mask and etching the cured film to the substrate surface to form an inversion pattern.

Description

[Technical Field]

[0001] The present invention relates to a pattern forming method and an article manufacturing method. [Background technology]

[0002] In semiconductor devices and MEMS, the demand for miniaturization is increasing, and imprint technology (optical imprint technology) is attracting attention as a microfabrication technology. In imprint technology, a mold with a fine uneven pattern formed on its surface is brought into contact with a curable composition supplied (coated) onto a substrate, and the curable composition is cured. This transfers the pattern of the mold to the cured film of the curable composition, forming the pattern on the substrate. According to imprint technology, it is possible to form fine patterns (structures) on the order of several nanometers on a substrate (see Patent Document 1).

[0003] An example of a pattern formation method using imprint technology is described below. First, a liquid curable material is discretely dropped (placed) onto the pattern formation area on the substrate using an inkjet method. The droplets of curable composition placed on the pattern formation area spread out on the substrate. This phenomenon is called press spreading. Next, a mold is brought into contact with (pressed against) the curable composition on the substrate. As a result, the droplets of curable composition spread out parallel to the substrate surface throughout the gap between the substrate and the mold by capillary action. This phenomenon is called spreading. The curable composition is also filled into the recesses that make up the pattern of the mold by capillary action. This phenomenon is called filling. The time until spreading and filling are completed is called the filling time. Once the filling of the curable composition is complete, light is irradiated onto the curable composition to cure it. Then, the mold is separated from the cured curable composition on the substrate. By performing these steps, the pattern of the mold is transferred to the curable composition on the substrate, and the pattern of the cured film of the curable composition is formed.

[0004] When processing a substrate using a pattern obtained using imprint technology as a mask, a process called an inversion process can be applied. Patent Document 2 discloses the following inversion process steps: An inversion layer is formed on the uneven pattern (inversion layer formation step), and the inversion layer material is embedded in the recesses. The inversion layer material is also laminated on the upper part of the convex part of the uneven pattern, becoming an excess inversion layer. The excess inversion layer is removed so as to expose the top surface of the convex part of the uneven pattern of the cured film of the curable composition (excess inversion layer removal step), exposing the inversion layer embedded in the recesses. The exposed inversion layer is used as a mask, and the remaining film of the uneven pattern and the carbon-based material layer below it are etched to form an inversion pattern (lower layer etching step). In this specification, the remaining film refers to the cured film remaining between the recesses (convex part of the mold pattern) of the curable film of the curable composition and the substrate. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 6584578 [Patent Document 2] Japanese Patent Publication No. 2016-162862 [Patent Document 3] Japanese Patent Publication No. 2007-186570 [Patent Document 4] Special Publication No. 2009-503139 [Non-patent literature]

[0006] [Non-Patent Document 1] J. Electrochem. Soc., 130, p143(1983) [Overview of the project] [Problems that the invention aims to solve]

[0007] In conventional inversion processes, it was necessary to form a layer with higher dry etching resistance than the curable composition, such as a spin-on-carbon (SOC) layer, beneath the curable composition for imprinting.

[0008] Furthermore, conventional inversion processes required minimizing the residual film of the curable composition, which has low dry etching resistance. This presented a challenge: if foreign matter became trapped between the mold and the underlying layer, the mold would be damaged.

[0009] This invention has been made in view of the problems of the prior art, and its exemplary objective is to provide new technologies for pattern formation methods and article manufacturing methods. [Means for solving the problem]

[0010] According to one aspect of the present invention, a pattern forming method comprising: an arrangement step of arranging a curable composition (A) containing at least a polymerizable compound (a) on a substrate; a contact step of bringing the curable composition (A) on the substrate into contact with a mold having irregularities after the arrangement step; a curing step of curing the curable composition (A) after the contact step to form a cured film; and a separation step of separating the curable composition (A) and the mold after the curing step, wherein the thickness of the residual film sandwiched between the most convex part of the irregularities of the mold and the substrate is 50 nm or more, and the mold The pattern forming method is characterized in that the height difference of the unevenness is less than or equal to the thickness of the remaining film, and the pattern forming method further comprises: a forming step of forming an inversion layer on the unevenness transferred from the mold onto the cured film; a removal step of removing the upper part of the inversion layer so as to expose the top surface of the convex portion of the unevenness formed on the cured film, with the inversion layer embedded in the recess of the unevenness formed on the cured film; and an etching step of using the inversion layer embedded in the recess as a mask and etching the cured film to the substrate surface to form an inversion pattern. [Effects of the Invention]

[0011] According to the present invention, for example, new technologies related to a pattern formation method and an article manufacturing method can be provided.

Brief Description of Drawings

[0012] [Figure 1] A diagram for explaining from the arrangement step to the separation step of the pattern formation method of the present invention. [Figure 2] A diagram for comparatively explaining the breakage behavior of a mold pattern due to foreign matter. [Figure 3] A diagram for explaining the inversion process of the pattern formation method of the present invention.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0014] As a result of intensive studies, the present inventors have devised an inversion process in which the SOC layer becomes unnecessary in the imprint technique. Further, in this inversion process, it has been found that the possibility of damage to the mold pattern due to sandwiching foreign matter that may unintentionally mix between the mold and the substrate is low.

[0015] [Curable Composition] The curable composition (A) in the present invention is a composition containing at least a component (a) which is a polymerizable compound and a component (b) which is a photopolymerization initiator. The curable composition (A) in the present invention may further contain a non-polymerizable compound (c) and a component (d) which is a solvent.

[0016] Furthermore, in this specification, a cured film means a film obtained by polymerizing and curing a curable composition (A) on a substrate. The cured film has a patterned shape on its surface.

[0017] <Component (a): Polymerizable compound> Component (a) is a polymerizable compound. In this specification, a polymerizable compound is a compound that reacts with polymerization factors (such as radicals) generated from a photopolymerization initiator (component (b)) to form a film made of a polymer compound through a chain reaction (polymerization reaction).

[0018] Examples of such polymerizable compounds include radical polymerizable compounds. The polymerizable compound that is component (a) may consist of only one type of polymerizable compound, or it may consist of multiple types of polymerizable compounds.

[0019] Examples of radical polymerizable compounds include (meth)acrylic compounds, styrene compounds, vinyl compounds, allyl compounds, fuma compounds, and maleyl compounds. A (meth)acrylic compound is a compound having one or more acryloyl groups or methacryloyl groups. Examples of monofunctional (meth)acrylic compounds having one acryloyl group or methacryloyl group include, but are not limited to, the following. Phenoxyethyl (meth)acrylate, phenoxy-2-methylethyl (meth)acrylate, phenoxyethoxyethyl (meth)acrylate, 3-phenoxy-2-hydroxypropyl (meth)acrylate, 2-phenylphenoxyethyl (meth)acrylate, 4-phenylphenoxyethyl (meth)acrylate, 3-(2-phenylphenyl)-2-hydroxypropyl (meth)acrylate, EO-modified p-cumylphenol (meth)acrylate, 2-bromophenoxyethyl (meth)acrylate, 2,4-dibromophenoxyethyl (meth)acrylate, 2,4,6-Tribromophenoxyethyl (meth)acrylate, EO-modified phenoxy(meth)acrylate, PO-modified phenoxy(meth)acrylate, polyoxyethylene nonylphenyl ether (meth)acrylate, isobornyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, bornyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate Acrylate, cyclohexyl (meth)acrylate, 4-butylcyclohexyl (meth)acrylate, acryloylmorpholine, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, amyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pliers Isoamyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, octyl(meth)acrylate, isooctyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl(meth)acrylate, decyl(meth)acrylate, isodecyl(meth)acrylate, undecyl(meth)acrylate, dodecyl(meth)acrylate, lauryl(meth)acrylate, stearyl(meth)acrylate, isostearyl(meth)acrylate, benzyl(meth)acrylate, Tetrahydrofurfuryl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, polyethylene glycol mono (meth)acrylate, polypropylene glycol mono (meth)acrylate, methoxyethylene glycol (meth)acrylate, ethoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, diacetone (meth)acrylamide, isobutoxymethyl (meth)acrylamide, N,N-dimethyl(meth)acrylamide, t-octyl(meth)acrylamide, dimethylaminoethyl(meth)acrylate, diethylaminoethyl(meth)acrylate, 7-amino-3,7-dimethyloctyl(meth)acrylate, N,N-diethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, 1- or 2-naphthyl(meth)acrylate, 1- or 2-naphthylmethyl(meth)acrylate, 3- or 4-phenoxybenzyl(meth)acrylate, cynoabenzyl(meth)acrylate,

[0020] Examples of commercially available monofunctional (meth)acrylic compounds mentioned above include, but are not limited to, the following: Aronix (registered trademark) M101, M102, M110, M111, M113, M117, M5700, TO-1317, M120, M150, M156 (all manufactured by Toagosei), MEDOL10, M IBDOL10, CHDOL10, MMDOL30, MEDOL30, MIBDOL30, CHDOL30, LA, IBXA, 2-MTA, HPA, Viscoat #150, #155, #158, #19 0, #192, #193, #220, #2000, #2100, #2150 (all manufactured by Osaka Organic Chemical Industry), Light Acrylate BO-A, EC-A, DMP-A, THF-A, HOP-A, HOA-MPE, HOA-MPL, PO-A, P-200A, NP-4EA, NP-8EA, Epoxy Ester M-600A, POB-A, OPP-EA (all manufactured by Kyoeisha Chemical), KAYARAD (registered trademark) TC110S, R-564, R-128H (all manufactured by Nippon Kayaku), NK Ester AMP-10G, AMP-20G, A-LEN-10 (all manufactured by Shin Nakamura Chemical Industry), FA-511A, 512A, 513A (all manufactured by Hitachi Chemical), PHE, CEA, PHE-2, PHE-4, BR-31, BR-31M, BR-32 (all manufactured by Daiichi Kogyo Seiyaku), VP (manufactured by BASF), ACMO, DMAA, DMAPAA (all manufactured by Kojin)

[0021] Furthermore, examples of polyfunctional (meth)acrylic compounds having two or more acryloyl groups or methacryloyl groups include, but are not limited to, the following. Trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, EO,PO-modified trimethylolpropane tri(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(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, 1, 9-Nonanediol di(meth)acrylate, 1,10-Decanediol di(meth)acrylate, 1,3-Adamantane dimethanol di(meth)acrylate, Tris(2-Hydoxyethyl)isocyanurate tri(meth)acrylate, Tris(Acryloyloxy)isocyanurate, Bis(Hydroxymethyl)tricyclodecane di(meth)acrylate, Dipentaerythritol penta(meth)acrylate, Dipentaerythritol hexa(meth)acrylate, EO-modified 2,2-bis(4-((meth)acryloxy)phenyl)propane, PO-modified 2,2-bis(4-((meth)acryloxy)phenyl)propane, EO,PO-modified 2,2-bis(4-((meth)acryloxy)phenyl)propane, o-, m- or p-Benzene di(meth)acrylate, o-, m- or p-Xylylene di(meth)acrylate

[0022] Examples of commercially available polyfunctional (meth)acrylic compounds mentioned above include, but are not limited to, the following: Yupimer® UV SA1002, SA2007 (both manufactured by Mitsubishi Chemical), Viscoat #195, #230, #215, #260, #335HP, #295, #300, #360, #700, GPT, 3PA (all manufactured by Osaka Organic Chemical Industry), Light Acrylate 4EG-A, 9EG-A, NP-A, DCP-A, BP-4EA, BP-4PA, TMP-A, PE-3A, PE-4A, DPE-6A (all manufactured by Kyoeisha Chemical), KAYARAD® PET-30, TMPTA, R-604, DPHA, DPCA-20, -30, -60, -120, HX-620, D-310, D-330 (all manufactured by Nippon Kayaku), Aronix® M208, M210, M215, M220, M240, M305, M309, M310, M315, M325, M400 (all manufactured by Toagosei), Lipoxy® VR-77, VR-60, VR-90 (all manufactured by Showa Polymer), Ogusol EA-0200, Ogusol EA-0300 (all manufactured by Osaka Gas Chemical)

[0023] In the above-mentioned group of compounds, (meth)acrylate means acrylate or methacrylate having an equivalent alcohol residue. (meth)acryloyl group means acryloyl group or methacryloyl group having an equivalent alcohol residue. EO represents ethylene oxide, and EO-modified compound A represents a compound in which the (meth)acrylic acid residue and alcohol residue of compound A are linked via a block structure of ethylene oxide group. Furthermore, PO represents propylene oxide, and PO-modified compound B represents a compound in which the (meth)acrylic acid residue and alcohol residue of compound B are linked via a block structure of propylene oxide group.

[0024] Specific examples of styrene compounds include, but are not limited to, the following. Alkylstyrenes such as styrene, 2,4-dimethyl-α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 2,6-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene, 2,4,6-trimethylstyrene, 2,4,5-trimethylstyrene, pentamethylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, 2,4-diisopropylstyrene, butylstyrene, hexylstyrene, heptylstyrene and octylstyrene; fluorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, o-bromostyrene, m-bromostyrene, p-bromostyrene, dibromostyrene and iodose Halide styrenes such as ethylene; compounds having a styryl group as a polymerizable functional group, such as nitrostyrene, acetylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2-vinylbiphenyl, 3-vinylbiphenyl, 4-vinylbiphenyl, 1-vinylnaphthalene, 2-vinylnaphthalene, 4-vinyl-p-terphenyl, 1-vinylanthracene, α-methylstyrene, o-isopropenyltoluene, m-isopropenyltoluene, p-isopropenyltoluene, 2,3-dimethyl-α-methylstyrene, 3,5-dimethyl-α-methylstyrene, p-isopropyl-α-methylstyrene, α-ethylstyrene, α-chlorostyrene, divinylbenzene, diisopropylbenzene, and divinylbiphenyl.

[0025] Specific examples of vinyl compounds include, but are not limited to, the following. Compounds having a vinyl group as a polymerizable functional group, such as vinylpyridine, vinylpyrrolidone, vinylcarbazole, vinyl acetate, and acrylonitrile; conjugated diene monomers such as butadiene, isoprene, and chloroprene; vinyl halides such as vinyl chloride and vinyl bromide; vinylidenes such as vinylidene chloride; vinyl esters of organic carboxylic acids and their derivatives (vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, divinyl adipate, etc., (meth)acrylonitrile, etc.)

[0026] In this specification, (meth)acrylonitrile is a general term for acrylonitrile and methacrylonitrile.

[0027] Examples of allyl compounds include, but are not limited to, the following: Allyl acetate, allyl benzoate, diallyl adipate, diallyl terephthalate, diallyl isophthalate, diallyl phthalate

[0028] Examples of fumaric compounds include, but are not limited to, the following: Dimethyl fumarate, diethyl fumarate, diisopropyl fumarate, di-sec-butyl fumarate, diisobutyl fumarate, di-n-butyl fumarate, di-2-ethylhexyl fumarate, dibenzyl fumarate

[0029] Examples of maleyl compounds include, but are not limited to, the following: Dimethyl maleate, diethyl maleate, diisopropyl maleate, di-sec-butyl maleate, diisobutyl maleate, di-n-butyl maleate, di-2-ethylhexyl maleate, dibenzyl maleate

[0030] Other radical polymerizable compounds include, but are not limited to, the following: Dialkyl esters of itaconic acid and their derivatives (dimethyl itaconic acid, diethyl itaconic acid, diisopropyl itaconic acid, di-sec-butyl itaconic acid, diisobutyl itaconic acid, di-n-butyl itaconic acid, di-2-ethylhexyl itaconic acid, dibenzyl itaconic acid, etc.), N-vinylamide derivatives of organic carboxylic acids (N-methyl-N-vinylacetamide, etc.), maleimides and their derivatives (N-phenylmaleimide, N-cyclohexylmaleimide, etc.)

[0031] When component (a) is composed of multiple types of compounds having one or more polymerizable functional groups, it is preferable to include both monofunctional and polyfunctional compounds. This is because combining monofunctional and polyfunctional compounds yields a cured film with an excellent balance of performance, such as high mechanical strength, high dry etching resistance, and high heat resistance.

[0032] The polymerizable compound (a) is preferably low in volatility. Therefore, the boiling points of the polymerizable compound (a), which may contain multiple types, are preferably all 250°C or higher, more preferably all 300°C or higher, and even more preferably all 350°C or higher under normal pressure. The boiling point of the polymerizable compound (a) generally correlates with its molecular weight. Therefore, the polymerizable compound (a) is preferably all 200 or higher in molecular weight, more preferably all 240 or higher, and even more preferably all 250 or higher. However, even if the molecular weight is 200 or less, if the boiling point is 250°C or higher, it can be preferably used as the polymerizable compound (a) of the present invention.

[0033] Furthermore, the vapor pressure of polymerizable compound (a) at 80°C is preferably 0.001 mmHg or less. Heating is preferred to accelerate the volatilization of solvent (d), which will be described later, and this is to suppress the volatilization of polymerizable compound (a) during heating.

[0034] The boiling points and vapor pressures of various organic compounds under normal pressure can be calculated using methods such as Hansen Solubility Parameters in Practice (HSPiP) 5th Edition, section 5.3.04.

[0035] <Component (a) of Onishi (OP)> V is the dry etching rate of the organic compound, N is the total number of atoms in the organic compound, and N is the total number of carbon atoms in the composition. C , and the total number of oxygen atoms in the composition N O It is known that the relationship is given by the following equation (1) (Non-Patent Document 1). V∝N / (N C -N O ) Formula (1) Here, N / (N C -N O This parameter is commonly known as the "Onishi parameter" (hereinafter referred to as OP). For example, Patent Document 3 describes a technique for obtaining a photocurable composition with high dry etching resistance by using a polymerizable compound component with a small OP.

[0036] According to equation (1) above, organic compounds with a high concentration of oxygen atoms in the molecule, or with fewer aromatic or alicyclic ring structures, have a larger OP value and a faster dry etching rate.

[0037] The curable composition used in the present invention preferably has an OP of component (a) of 2.00 to 3.00, more preferably 2.00 to 2.80, and particularly preferably 2.00 to 2.60. Setting it to 3.00 or less gives the cured film of curable composition (A) high dry etching resistance. Setting it to 2.00 or more makes it easy to remove the cured film of curable composition (A) after processing the underlying layer with the cured film of curable composition (A). Component (a) is a plurality of polymerizable compounds a1, a2, ..., a n If the composition is as follows, OP is calculated as a weighted average value based on mole fractions (mole fraction weighted average value) as shown in formula (2) below.

number

[0038] In order to make the OP of the (a) component 2.00 or more and 3.00 or less, it is preferable to contain at least a compound having a ring structure such as an aromatic structure, an aromatic heterocyclic structure or an alicyclic structure as the (a) component.

[0039] As the aromatic structure, the number of carbon atoms is preferably 6 to 22, more preferably 6 to 18, and still more preferably 6 to 10. Specific examples of the aromatic ring include the following. Benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, phenalene ring, fluorene ring, benzocyclooctene ring, acenaphthylene ring, biphenylene ring, indene ring, indane ring, triphenylene ring, pyrene ring, chrysene ring, perylene ring, tetrahydronaphthalene ring.

[0040] Among the above-mentioned aromatic rings, a benzene ring or a naphthalene ring is preferable, and a benzene ring is more preferable. The aromatic ring may have a structure in which a plurality are linked, and examples thereof include a biphenyl ring and a bisphenyl ring.

[0041] As the aromatic heterocyclic structure, the number of carbon atoms is preferably 1 to 12, more preferably 1 to 6, and still more preferably 1 to 5. Specific examples of the aromatic heterocyclic ring include the following. Thiophene ring, furan ring, pyrrole ring, imidazole ring, pyrazole ring, triazole ring, tetrazole ring, thiazole ring, thiadiazole ring, oxadiazole ring, oxazole ring, pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, isoindole ring, indole ring, indazole ring, purine ring, quinolidine ring, isoquinoline ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinazoline ring, cinnoline ring, carbazole ring, acridine ring, phenazine ring, phenothiazine ring, phenoxathiine ring, phenoxazine ring

[0042] For alicyclic structures, the number of carbon atoms is preferably 3 or more, more preferably 4 or more, and even more preferably 6 or more. Furthermore, for alicyclic structures, the number of carbon atoms is preferably 22 or less, more preferably 18 or less, even more preferably 6 or less, and even more preferably 5 or less. Specific examples include the following. Cyclopropane ring, cyclobutane ring, cyclobutene ring, cyclopentane ring, cyclohexane ring, cyclohexene ring, cycloheptane ring, cyclooctane ring, dicyclopentadiene ring, spirodecane ring, spirononane ring, tetrahydrodicyclopentadiene ring, octahydronaphthalene ring, decahydronaphthalene ring, hexahydroindan ring, bornane ring, norbornane ring, norbornene ring, isobornane ring, tricyclodecane ring, tetracyclododecane ring, adamantane ring

[0043] Specific examples of polymerizable compounds (a) having a boiling point of 250°C or higher and a ring structure include, but are not limited to, the following. Dicyclopentanyl acrylate (boiling point 262°C, molecular weight 206), Dicyclopentenyl acrylate (boiling point 270°C, molecular weight 204), 1,3-Cyclohexanedimethanol diacrylate (boiling point 310°C, molecular weight 252), 1,4-Cyclohexanedimethanol diacrylate (boiling point 339°C, molecular weight 252), 4-Hexylresorcinol diacrylate (boiling point 379°C, molecular weight 302), 6-Phenylhexane-1,2-diol diacrylate (boiling point 381°C, molecular weight 302), 7-Phenylheptane-1,2-diol diacrylate (boiling point 393°C, molecular weight 316), 1,3-Bis((2-hydroxyethoxy)methyl)cyclohexanediacrylate (boiling point 403°C, molecular weight 340), 8-Phenyloctane-1,2-diol diacrylate (boiling point 404°C, molecular weight 330), 1,3-Bis((2-hydroxyethoxy)methyl)benzenediaacrylate (boiling point 408°C, molecular weight 334), 1,4-Bis((2-hydroxyethoxy)methyl)cyclohexanediacrylate (boiling point 445°C, molecular weight 340), 3-Phenoxybenzylacrylate (mPhOBzA, OP2.54, boiling point 367.4℃, vapor pressure 0.0004mmHg at 80℃, molecular weight 254.3), [ka] 1-Naphthyl acrylate (NaA, OP2.27, boiling point 317°C, vapor pressure 0.0422 mmHg at 80°C, molecular weight 198), [ka] 2-Phenylphenoxyethyl acrylate (PhPhOEA, OP2.57, boiling point 364.2℃, vapor pressure at 80℃ 0.0006 mmHg, molecular weight 268.3), [ka] 1-Naphthylmethyl acrylate (Na1MA, OP2.33, boiling point 342.1℃, vapor pressure 0.042 mmHg at 80℃, molecular weight 212.2), [ka] 2-Naphthylmethyl acrylate (Na2MA, OP2.33, boiling point 342.1℃, vapor pressure 0.042 mmHg at 80℃, molecular weight 212.2), [ka] 4-Cyanobenzyl acrylate (CNBzA, OP2.44, boiling point 316°C, molecular weight 187), [ka] DVBzA (OP2.50, boiling point 304.6℃, vapor pressure at 80℃ 0.0848mmHg, molecular weight 214.3) as shown in the following formula, [ka] DPhPA (OP2.38, boiling point 354.5°C, vapor pressure 0.0022 mmHg at 80°C, molecular weight 266.3), as shown in the formula below, [ka] PhBzA (OP2.29, boiling point 350.4℃, vapor pressure 0.0022mmHg at 80℃, molecular weight 238.3) as shown in the following formula, [ka] FLMA (OP2.20, boiling point 349.3°C, vapor pressure 0.0018 mmHg at 80°C, molecular weight 250.3) as shown in the following formula, [ka] ATMA (OP2.13, boiling point 414.9°C, vapor pressure 0.0001 mmHg at 80°C, molecular weight 262.3), as shown in the formula below, [ka] The following formula represents DNaMA (OP2.00, boiling point 489.4℃, vapor pressure at 80℃ <0.0001 mmHg, molecular weight 338.4), [ka] Tricyclodecanedimethanol diacrylate (DCPDA, OP3.29, boiling point 342°C, vapor pressure 0.0024 mmHg at 80°C, molecular weight 304), [ka] m-Xylylenediacrylate (mXDA, OP3.20, boiling point 336°C, vapor pressure 0.0043 mmHg at 80°C, molecular weight 246), [ka] 1-Phenylethane-1,2-diyldiaacrylate (PhEDA, OP3.20, vapor pressure 0.0057 mmHg at 80°C, boiling point 354°C, molecular weight 246), [ka] 2-Phenyl-1,3-propanediol diacrylate (PhPDA, OP3.18, boiling point 340°C, vapor pressure 0.0017 mmHg at 80°C, molecular weight 260), [ka] The following formula shows VmXDA (OP3.00, boiling point 372.4°C, vapor pressure at 80°C 0.0005 mmHg, molecular weight 272.3), [ka] BPh44DA (OP2.63, boiling point 444℃, vapor pressure at 80℃ <0.0001mmHg, molecular weight 322.3) as shown in the formula below, [ka] BPh43DA (OP2.63, boiling point 439.5℃, vapor pressure at 80℃ <0.0001mmHg, molecular weight 322.3) as shown in the formula below, [ka] DPhEDA (OP2.63, boiling point 410°C, vapor pressure <0.0001 mmHg at 80°C, molecular weight 322.3) as shown in the following formula, [ka] BPMDA (OP2.68, boiling point 465.7°C, vapor pressure <0.0001 mmHg at 80°C, molecular weight 364.4) as shown in the following formula, [ka] Na13MDA (OP2.71, boiling point 438.8°C, vapor pressure <0.0001 mmHg at 80°C, molecular weight 296.3), as shown in the formula below, [ka]

[0044] The proportion of component (a) in the curable composition (A) is preferably 40% to 99% by weight of the total mass of component (a), component (b) described later, and component (c) described later, i.e., the total mass of all components excluding solvent (d). More preferably, it is 50% to 95% by weight, and even more preferably 60% to 90% by weight. By increasing the proportion of component (a) to 40% by weight or more, the mechanical strength of the cured film of the curable composition is increased. Furthermore, by increasing the proportion of component (a) to 99% by weight or less, the proportions of components (b) and (c) can be increased, and properties such as a fast photopolymerization rate can be obtained.

[0045] At least a portion of component (a) of the present invention, which may be added in multiple forms, may be a polymer having polymerizable functional groups. The polymer preferably contains at least a ring structure such as an aromatic structure, an aromatic heterocyclic structure, or an alicyclic structure. For example, it is preferable to contain at least one of the constituent units represented by any of the following formulas (1) to (6). [ka]

[0046] In formulas (1) to (6), each substituent R is independently a substituent containing a substructure that includes an aromatic ring, 1 R is a hydrogen atom or a methyl group. In this specification, the portion of the constituent unit represented by formulas (1) to (6), excluding R, is used as the main chain of a specific polymer. The formula weight of substituent R is 80 or more, preferably 100 or more, more preferably 130 or more, and even more preferably 150 or more. The upper limit is practically 500 or less.

[0047] Polymers having polymerizable functional groups are typically compounds with a weight-average molecular weight of 500 or more, preferably 1,000 or more, and more preferably 2,000 or more. There is no specific upper limit for the weight-average molecular weight, but for example, 50,000 or less is preferred. By setting the weight-average molecular weight above the lower limit, the boiling point can be set to 250°C or higher, and the mechanical properties after curing can be further improved. Furthermore, by setting the weight-average molecular weight below the upper limit, solubility in solvents is high, the fluidity of discretely arranged droplets is maintained without excessive viscosity, and the flatness of the liquid film plane can be further improved. In this invention, unless otherwise specified, the weight-average molecular weight (Mw) refers to that measured by gel permeation chromatography (GPC).

[0048] Specific examples of polymerizable functional groups in polymers include (meth)acryloyl groups, epoxy groups, oxetane groups, methylol groups, methylol ether groups, and vinyl ether groups. From the viewpoint of ease of polymerization, (meth)acryloyl groups are particularly preferred.

[0049] When a polymer having polymerizable functional groups is added as at least a portion of component (a), its blending ratio can be freely set as long as it falls within the viscosity specifications described later. The blending ratio of the polymer is preferably 0.1% by weight or more and 60% by weight or less, more preferably 1% by weight or more and 50% by weight or less, and even more preferably 10% by weight or more and 40% by weight or less, based on the total mass of all components excluding solvent (d). By blending the polymer having polymerizable functional groups at 0.1% by weight or more, dry etching resistance, heat resistance, mechanical strength, and low volatility can be improved. Furthermore, by setting it to 60% by weight or less, it can be kept within the upper viscosity limit specifications described later.

[0050] <Component (b): Photopolymerization initiator> Component (b) is a photopolymerization initiator. In this specification, a photopolymerization initiator is a compound that senses light of a predetermined wavelength and generates the polymerization factors (radicals) described above. Specifically, a photopolymerization initiator is a polymerization initiator (radical generator) that generates radicals in response to light (infrared rays, visible light, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams such as electron beams, and radiation). Component (b) may consist of only one type of photopolymerization initiator or may consist of multiple types of photopolymerization initiators.

[0051] Examples of radical generators include, but are not limited to, the following: 2,4,5-triarylimidazole dimers which may have substituents such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o- or p-methoxyphenyl)-4,5-diphenylimidazole dimer; benzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone (Michler ketone), N,N'-tetraethyl-4,4'-diaminobenzophenone Benzophenone derivatives such as 4-methoxy-4'-dimethylaminobenzophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, and 4,4'-diaminobenzophenone; α-amino aromatic ketone derivatives such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one; 2-ethylanthraquinone, phenanthrenequinone, 2-t-butylanthraquinone, octamethylanthraquinone, and 1,2-benz Quinones such as anthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenantaraquinone, 2-methyl-1,4-naphthoquinone, and 2,3-dimethylanthraquinone; benzoin ether derivatives such as benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether; benzoin derivatives such as benzoin, methylbenzoin, ethylbenzoin, and propylbenzoin; benzyl Benzyl derivatives such as dimethyl ketal; acridine derivatives such as 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane; N-phenylglycine derivatives such as N-phenylglycine; acetophenone derivatives such as acetophenone, 3-methylacetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, and 2,2-dimethoxy-2-phenylacetophenone; thioxanthone derivatives such as thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, and 2-chlorothioxanthone;Acyl phosphine oxide derivatives such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; oxime ester derivatives such as 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyl oxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyloxime); xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one;

[0052] Examples of commercially available radical generators mentioned above include, but are not limited to, the following. Irgacure 184, 369, 651, 500, 819, 907, 784, 2959, CGI-1700, -1750, -1850, CG24-61, Darocur 1116, 1173, Lucirin (registered trademark) TPO, LR8893, LR8970 (all manufactured by BASF), Yubekrill P36 (manufactured by UCB)

[0053] Of the radical generators mentioned above, component (b) is preferably an acylphosphine oxide polymerization initiator. The acylphosphine oxide polymerization initiators among the radical generators mentioned above are as follows: Acyl phosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0054] The blending ratio of component (b) in the curable composition (A) is preferably 0.1% by weight or more and 50% by weight or less, relative to the total mass of component (a), component (b), and component (c) described later, i.e., the total mass of all components excluding solvent (d). Furthermore, the blending ratio of component (b) in the curable composition (A) is more preferably 0.1% by weight or more and 20% by weight or less, and even more preferably 1% by weight or more and 20% by weight or less, relative to the total mass of all components excluding solvent (d). By setting the blending ratio of component (b) to 0.1% by weight or more, the curing rate of the composition can be increased and the reaction efficiency can be improved. Furthermore, by setting the blending ratio of component (b) to 50% by weight or less, a cured film with a certain degree of mechanical strength can be obtained.

[0055] <Component (c): Non-polymerizable compound> In addition to components (a) and (b) described above, the curable composition (A) in the present invention may further contain a non-polymerizable compound as component (c), to the extent that it does not impair the effects of the present invention, depending on the purpose. Examples of such component (c) include compounds that do not have polymerizable functional groups such as (meth)acryloyl groups and do not have the ability to sense light of a predetermined wavelength and generate the polymerization factors (radicals) described above. Examples of non-polymerizable compounds include sensitizers, hydrogen donors, internally added mold release agents, antioxidants, polymer components, and other additives. Component (c) may contain multiple types of the compounds described above.

[0056] Sensitizers are compounds added as needed to accelerate polymerization reactions or improve the conversion rate. Sensitizers may be used individually or in combination of two or more types.

[0057] Examples of sensitizers include sensitizing dyes. Sensitizing dyes are compounds that are excited by absorbing light of a specific wavelength and interact with the photopolymerization initiator, which is component (b). Here, interaction refers to energy transfer or electron transfer from the excited sensitizing dye to the photopolymerization initiator, which is component (b). Specific examples of sensitizing dyes are listed below, but are not limited to these. Anthracene derivatives, anthraquinone derivatives, pyrene derivatives, perylene derivatives, carbazole derivatives, benzophenone derivatives, thioxanthone derivatives, xanthone derivatives, coumarin derivatives, phenothiazine derivatives, camphaquinone derivatives, acridine dyes, thiopyrillium salt dyes, merocyanine dyes, quinoline dyes, styrylquinoline dyes, ketocoumarin dyes, thioxanthene dyes, xanthene dyes, oxonol dyes, cyanine dyes, rhodamine dyes, pyrylium salt dyes

[0058] The hydrogen donor is a compound that reacts with the initiation radicals and polymerization growth end radicals generated from the photopolymerization initiator (component (b)) to generate more reactive radicals. It is preferable to add the hydrogen donor when the photopolymerization initiator (component (b)) is a photoradical generator.

[0059] Specific examples of such hydrogen donors include, but are not limited to, the following. Amine compounds such as n-butylamine, di-n-butylamine, tri-n-butylphosphine, allylthiourea, s-benzylisothiuronium-p-toluenesulfinate, triethylamine, diethylaminoethyl methacrylate, triethylenetetramine, 4,4'-bis(dialkylamino)benzophenone, ethyl N,N-dimethylaminobenzoate, isoamyl N,N-dimethylaminobenzoate, pentyl-4-dimethylaminobenzoate, triethanolamine, N-phenylglycine, and other amine compounds, as well as mercapto compounds such as 2-mercapto-N-phenylbenzimidazole and mercaptopropionate.

[0060] The hydrogen donor may be used individually or in a mixture of two or more types. Furthermore, the hydrogen donor may also function as a sensitizer.

[0061] To reduce the interfacial bonding force between the mold and the curable composition, that is, to reduce the release force in the release step described later, an internally added release agent can be added to the curable composition. In this specification, "internally added" means that it is added to the curable composition in advance before the curable composition placement step. As the internally added release agent, surfactants such as silicone-based surfactants, fluorine-based surfactants, and hydrocarbon-based surfactants can be used. However, in this invention, as described later, there are restrictions on the amount of fluorine-based surfactants that can be added. The internally added release agent in this invention is assumed to be nonpolymerizable. One type of internally added release agent may be used alone, or two or more types may be used in mixture form.

[0062] Fluorine-based surfactants include the following: Polyalkylene oxide (polyethylene oxide, polypropylene oxide, etc.) adducts of alcohols having perfluoroalkyl groups, and polyalkylene oxide (polyethylene oxide, polypropylene oxide, etc.) adducts of perfluoropolyethers.

[0063] Furthermore, fluorinated surfactants may have hydroxyl groups, alkoxy groups, alkyl groups, amino groups, thiol groups, etc., in part of their molecular structure (for example, terminal groups). Examples include pentadecaethylene glycol mono-1H,1H,2H,2H-perfluorooctyl ether.

[0064] Commercially available fluorinated surfactants may be used. Examples of commercially available fluorinated surfactants include the following: Megafac® F-444, TF-2066, TF-2067, TF-2068, abbreviated DEO-15 (all manufactured by DIC), Florard FC-430, FC-431 (all manufactured by Sumitomo 3M), Surflon® S-382 (manufactured by AGC), EFTOP EF-122A, 122B, 122C, EF-121, EF-126, EF-127, MF-100 (all manufactured by Tochem Products), PF-636, PF-6320, PF-656, PF-6520 (all manufactured by OMNOVA Solutions), Unidyne® DS-401, DS-403, DS-451 (all manufactured by Daikin Industries), Futergent® 250, 251, 222F, 208G (all manufactured by Neos)

[0065] Furthermore, the internally added release agent may be a hydrocarbon surfactant. Examples of hydrocarbon surfactants include alkyl alcohol polyalkylene oxide adducts and polyalkylene oxides, which are obtained by adding an alkylene oxide with 2 to 4 carbon atoms to an alkyl alcohol with 1 to 50 carbon atoms.

[0066] Examples of alkyl alcohol polyalkylene oxide adducts include the following: Methyl alcohol ethylene oxide adduct, decyl alcohol ethylene oxide adduct, lauryl alcohol ethylene oxide adduct, cetyl alcohol ethylene oxide adduct, stearyl alcohol ethylene oxide adduct, stearyl alcohol ethylene oxide / propylene oxide adduct

[0067] Furthermore, the terminal group of an alkyl alcohol polyalkylene oxide adduct is not simply limited to a hydroxyl group that can be produced by adding a polyalkylene oxide to an alkyl alcohol. Such a hydroxyl group may be substituted with other substituents, such as polar functional groups like carboxyl groups, amino groups, pyridyl groups, thiol groups, or silanol groups, or hydrophobic functional groups like alkyl groups or alkoxy groups.

[0068] Examples of polyalkylene oxides include the following: Polyethylene glycol, polypropylene glycol, their mono or dimethyl ethers, mono or dioctyl ethers, mono or dinonyl ethers, mono or didecyl ethers, monoadipic acid esters, monooleic acid esters, monostearate esters, monosuccinate esters

[0069] Commercially available alkyl alcohol polyalkylene oxide adducts may be used. Examples of commercially available alkyl alcohol polyalkylene oxide adducts include the following: Polyoxyethylene methyl ether (methyl alcohol ethylene oxide adduct) (BLAUNON MP-400, MP-550, MP-1000) manufactured by Aoki Oil & Fat Industry Co., Ltd., polyoxyethylene decyl ether (decyl alcohol ethylene oxide adduct) (FINESURF D-1303, D-1305, D-1307, D-1310) manufactured by Aoki Oil & Fat Industry Co., Ltd., polyoxyethylene lauryl ether (lauryl alcohol ethylene oxide adduct) (BLAUNON EL-1505) manufactured by Aoki Oil & Fat Industry Co., Ltd., polyoxyethylene cetyl ether (cetyl alcohol ethylene oxide adduct) (BLAUNON CH-305, CH-310) manufactured by Aoki Oil & Fat Industry Co., Ltd., polyoxyethylene stearyl ether (stearyl alcohol ethylene oxide adduct) (BLAUNON SR-705, SR-707, SR-715, SR-720, SR-730, SR-750), random polymerization type polyoxyethylene polyoxypropylene stearyl ether manufactured by Aoki Oil & Fat Industry (BLAUNON SA-50 / 50 1000R, SA-30 / 70 2000R), polyoxyethylene methyl ether manufactured by BASF (Pluriol® A760E), polyoxyethylene alkyl ether manufactured by Kao (Emulgen series)

[0070] Furthermore, commercially available polyalkylene oxides may be used, such as BASF's ethylene oxide-propylene oxide copolymer (Pluronic PE6400).

[0071] Fluorine-based surfactants are effective as internally added mold release agents because they exhibit excellent mold release force reduction effects. The blending ratio of component (c) excluding the fluorine-based surfactant in curable composition (A) is preferably 0% by weight or more and 50% by weight or less, relative to the total mass of component (a), component (b), and component (c), i.e., the total mass of all components excluding solvent (d). Furthermore, the blending ratio of component (c) excluding the fluorine-based surfactant in curable composition (A) is more preferably 0.1% by weight or more and 50% by weight or less, and even more preferably 0.1% by weight or more and 20% by weight or less, relative to the total mass of all components excluding solvent (d). By setting the blending ratio of component (c) excluding the fluorine-based surfactant to 50% by weight or less, a cured film with a certain degree of mechanical strength can be obtained.

[0072] <Component (d): Solvent> The curable composition of the present invention contains, as component (d), a solvent having a boiling point of 80°C or higher and less than 250°C under normal pressure. Component (d) can be a solvent in which components (a), (b), and (c) dissolve, such as an alcohol-based solvent, a ketone-based solvent, an ether-based solvent, an ester-based solvent, or a nitrogen-containing solvent. Component (d) can be used alone or in combination of two or more types. The boiling point of component (d) under normal pressure should be 80°C or higher, preferably 140°C or higher, and particularly preferably 150°C or higher. The boiling point of component (d) under normal pressure should be less than 250°C, preferably 200°C or lower. If the boiling point of component (d) under normal pressure is less than 80°C, volatilization will proceed even during the arrangement process, impairing the stability of the process. Furthermore, if the boiling point of component (d) at atmospheric pressure is 250°C or higher, the volatilization of component (d) may be insufficient during the subsequent waiting process, and component (d) may remain in the cured film of the curable composition (A).

[0073] Examples of alcohol-based solvents include the following: Methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n-nonyl alcohol, 2,6-dimethylheptanol-4, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl Monoalcohol solvents such as alcohol, sec-heptadecyl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, phenylmethylcarbinol, diacetone alcohol, and cresol; polyhydric alcohol solvents such as ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, and glycerin.

[0074] Examples of ketone solvents include the following: Acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclohexanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone, phenthone

[0075] Examples of ether-based solvents include the following: Ethyl ether, iso-propyl ether, n-butyl ether, n-hexyl ether, 2-ethylhexyl ether, ethylene oxide, 1,2-propylene oxide, dioxolane, 4-methyldioxolane, dioxane, dimethyldioxane, 2-methoxyethanol, 2-ethoxyethanol, ethylene glycol diethyl ether, 2-n-butoxyethanol, 2-n-hexoxyethanol, 2-phenoxyethanol, 2-(2-ethylbutoxy)ethanol, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol Diethylene glycol mono-n-butyl ether, diethylene glycol di-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol di-n-butyl ether, 1-n-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monomethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran

[0076] Examples of ester solvents include the following: Diethyl carbonate, methyl acetate, ethyl acetate, amyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate, methyl acetoacetate, ethyl acetoacetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate Ethers, diethylene glycol acetate mono-n-butyl ether, propylene glycol acetate monomethyl ether, propylene glycol acetate monoethyl ether, propylene glycol acetate monopropyl ether, propylene glycol acetate monobutyl ether, dipropylene glycol acetate monomethyl ether, dipropylene glycol acetate monoethyl ether, glycol diacetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate

[0077] Examples of nitrogen-containing solvents include the following: N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone

[0078] Of the solvents mentioned above, ether-based solvents and ester-based solvents are preferred. More preferably, from the viewpoint of excellent film-forming properties, are ether-based solvents and ester-based solvents having a glycol structure.

[0079] Furthermore, the following are even more preferred solvents. Propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol acetate monomethyl ether, propylene glycol acetate monoethyl ether, propylene glycol acetate monopropyl ether.

[0080] Furthermore, propylene glycol monomethyl ether acetate is particularly preferred.

[0081] In the present invention, preferred solvents are those having at least one of the following: an ester structure, a ketone structure, a hydroxyl group, or an ether structure. Specifically, these are solvents selected individually or in mixtures thereof from propylene glycol monomethyl ether acetate (boiling point 146°C), propylene glycol monomethyl ether, cyclohexanone, 2-heptanone, γ-butyrolactone, and ethyl lactate.

[0082] Furthermore, in the present invention, a polymerizable compound having a boiling point of 80°C or higher and less than 250°C under normal pressure can also be used as component (d). Examples of polymerizable compounds having a boiling point of 80°C or higher and less than 250°C under normal pressure include the following: Cyclohexyl acrylate (boiling point 198°C), benzyl acrylate (boiling point 229°C), isobornyl acrylate (boiling point 245°C), tetrahydrofurfuryl acrylate (boiling point 202°C), trimethylcyclohexyl acrylate (boiling point 232°C), isooctyl acrylate (217°C), n-octyl acrylate (boiling point 228°C), ethoxyethoxyethyl acrylate (boiling point 230°C), divinylbenzene (boiling point 193°C), 1,3-diisopropenylbenzene (boiling point 218°C), styrene (boiling point 145°C), α-methylstyrene (boiling point 165°C)

[0083] In the arrangement step of the present invention, when using the inkjet method, the content of solvent (d) shall be 0% to 95% by volume, based on the total curable composition (A) being 100% by volume. Preferably, it shall be 70% to 85% by volume, and more preferably 70% to 80% by volume. By setting the content of solvent (d) to 70% by volume or more, it becomes possible to obtain a substantially continuous liquid film by allowing droplets to combine during the waiting step. On the other hand, if the content of solvent (d) is greater than 95% by volume, even if the droplets are dropped as densely as possible by the inkjet method, a thick film cannot be obtained after the evaporation of solvent (d).

[0084] When using the spin coating method in the arrangement step of the present invention, the solvent (d) content shall be 1% to 99.9% by volume, based on the total curable composition (A) being 100% by volume. Preferably, 10% to 99.9% by volume is preferred, 80% to 99.9% by volume is more preferred, and 90% to 99.9% by volume is particularly preferred. The appropriate content is determined from the control range of the rotation speed of the spin coating apparatus and the desired film thickness.

[0085] <Temperature during compounding of curable composition> When preparing the curable composition (A) in the present invention, at least components (a), (b), and (d) are mixed and dissolved under predetermined temperature conditions. Specifically, the predetermined temperature conditions are in the range of 0°C to 100°C. The same applies when the curable composition (A) contains component (c).

[0086] <Viscosity of curable composition> The curable composition (A) in this invention is a liquid. This is because, in the placement process described later, droplets of the curable composition (A) are placed on the substrate by an inkjet method or a spin coating method.

[0087] In the arrangement step of the present invention, when using the inkjet method, the viscosity of the curable composition (A) at 23°C, including the solvent (d), is 2 mPa·s or more and 60 mPa·s or less. Preferably, the viscosity is 5 mPa·s or more and 30 mPa·s or less, and more preferably 5 mPa·s or more and 15 mPa·s or less. If the viscosity of the curable composition (A) is less than 2 mPa·s, the droplet ejection performance by the inkjet method becomes unstable. Also, if the viscosity of the curable composition (A) is greater than 60 mPa·s, it is not possible to form droplets with a volume of approximately 1.0 to 3.0 pL, which is preferred in the present invention.

[0088] In the arrangement step of the present invention, when using the spin coating method, the viscosity of the curable composition (A) shall be 1 mPa·s or more and 100 mPa·s or less.

[0089] The viscosity at 23°C of the mixture of components of the curable composition (A) excluding solvent (d), i.e., the viscosity of the mixture after solvent (d) has evaporated from the curable composition (A), shall be 1 mPa·s or more and 10,000 mPa·s or less. Preferably, the viscosity shall be 30 mPa·s or more and 2,000 mPa·s or less, more preferably 120 mPa·s or more and 1,000 mPa·s or less, and even more preferably 200 mPa·s or more and 500 mPa·s or less. By making the viscosity of the components of the curable composition (A) excluding solvent (d) 1,000 mPa·s or less, the spread and fill processes are completed quickly when the curable composition (A) is brought into contact with the mold. Therefore, by using the curable composition (A) of the present invention, the imprint process can be carried out with high throughput, and pattern defects due to insufficient filling can be suppressed. Furthermore, by making the viscosity of the components of the curable composition (A) excluding the solvent (d) 1 mPa·s or higher, unwanted flow of droplets of the curable composition (A) after the solvent (d) has evaporated can be prevented. In addition, when the curable composition (A) is brought into contact with the mold, it becomes less likely for the curable composition (A) to flow out from the edges of the mold.

[0090] <Surface tension of curable compositions> Regarding the surface tension of the curable composition (A) in the present invention, it is preferable that the surface tension at 23°C for the composition of components excluding the solvent (component (d)) is 5 mN / m or more and 70 mN / m or less. Furthermore, it is more preferable that the surface tension at 23°C for the composition of components excluding the solvent (component (d)) is 7 mN / m or more and 50 mN / m or less, and even more preferable that it is 10 mN / m or more and 40 mN / m or less. The higher the surface tension, for example, if it is 5 mN / m or more, the stronger the capillary force, so that when the curable composition (A) is brought into contact with the mold, filling (spreading and filling) can be completed in a short time. In addition, by making the surface tension 70 mN / m or less, the cured film obtained by curing the curable composition becomes a cured film with a smooth surface.

[0091] <Contact angle of curable composition> Regarding the contact angle of the curable composition (A) in the present invention, for the composition of components excluding the solvent (component (d)), it is preferably 0° to 90° with respect to both the surface of the substrate and the surface of the mold, and particularly preferably 0° to 10°. If the contact angle is greater than 90°, capillary forces act in a negative direction (a direction that causes contraction of the contact interface between the mold and the curable composition) inside the mold pattern and in the gap between the substrate and the mold, which may prevent filling. The smaller the contact angle, the stronger the capillary forces, and therefore the faster the filling speed.

[0092] <Impurities present in the curable composition> The curable composition (A) in the present invention is preferably free of impurities as much as possible. Impurities refer to substances other than the components (a), (b), (c), and (d) described above. Therefore, the curable composition (A) in the present invention is preferably obtained through a purification process. Such a purification process is preferably filtration using a filter.

[0093] For filtration using a filter, it is preferable to mix components (a), (b), and (c) described above and then filter them using, for example, a filter with a pore size of 0.001 μm to 5.0 μm. When performing filtration using a filter, it is even more preferable to perform it in multiple stages or repeat it many times (circulating filtration). The liquid filtered by the filter may be filtered again, or multiple filters with different pore sizes may be used for filtration. Examples of filters used for filtration include, but are not particularly limited to, filters made of polyethylene resin, polypropylene resin, fluororesin, and nylon resin. By going through such a purification process, impurities such as particles mixed into the curable composition can be removed. This prevents impurities mixed into the curable composition from unintentionally causing irregularities in the cured film obtained after curing the curable composition, resulting in pattern defects.

[0094] Furthermore, when using the curable composition of the present invention to manufacture semiconductor integrated circuits, it is preferable to avoid, as much as possible, the inclusion of metal atoms (metallic impurities) in the curable composition in order to avoid interfering with the operation of the product. The concentration of metal impurities in the curable composition is preferably 10 ppm or less, and more preferably 100 ppb or less.

[0095] [substrate] In this specification, the component on which the curable composition (A) is placed is described as a substrate.

[0096] The substrate is a workpiece, and typically a silicon wafer is used. The substrate may have a workpiece layer on its surface. The substrate may also have other layers formed beneath the workpiece layer. Furthermore, if a quartz substrate is used as the substrate, a replica of the imprint mold (replica mold) can be manufactured. However, the substrate is not limited to silicon wafers or quartz substrates. The substrate can be arbitrarily selected from known semiconductor device substrates such as aluminum, titanium-tungsten alloy, aluminum-silicon alloy, aluminum-copper-silicon alloy, silicon oxide, and silicon nitride. The workpiece layer on the outermost surface of the substrate may be an insulating film containing at least silicon atoms. The workpiece layer on the outermost surface of the substrate may have improved adhesion to the curable composition (A) by surface treatment such as silane coupling treatment, silazane treatment, or deposition of an organic thin film. As a specific example of the organic thin film deposited as a surface treatment, for example, the adhesion layer described in Patent Document 4 can be used.

[0097] [Pattern formation method] Referring to Figure 1, the pattern formation method in the present invention will be described. The cured film formed by the present invention is preferably a film having a pattern of size 1 nm to 10 mm, and more preferably a film having a pattern of size 10 nm to 100 μm. The pattern formation method in the present invention utilizes an optical imprint method to form a film of the curable composition in the space between the mold and the substrate. However, the curable composition may be cured by other energy (e.g., heat, electromagnetic waves).

[0098] The pattern forming method of the present invention will be described below. The pattern forming method of the present invention may include, for example, a placement step, a waiting step, a contact step, a curing step, and a separation step. The placement step is a step of placing a liquid film of the curable composition (A) on a substrate. The waiting step is a step of waiting until the solvent component (d) of the curable composition (A) evaporates. The contact step is a step of bringing the curable composition (A) into contact with a mold. The curing step is a step of curing the curable composition (A). The separation step is a step of separating the mold from the cured film of the curable composition (A). The waiting step is performed after the placement step, the contact step is performed after the waiting step, the curing step is performed after the contact step, and the separation step is performed after the curing step.

[0099] Furthermore, the pattern forming method of the present invention includes an inversion layer formation step, an excess inversion layer removal step, and a residual film etching step. The inversion layer formation step is a step of forming an inversion layer on the cured film of the curable composition (A). The excess inversion layer removal step is a step of removing the inversion layer formed on the upper part of the convex portion of the cured film of the curable composition (A). The residual film etching step is a step of removing the residual film of the cured film of the curable composition (A) using the inversion layer remaining in the concave portion of the cured film of the curable composition (A) as a mask. The excess inversion layer removal step is performed after the inversion layer formation step, and the residual film etching step is performed after the excess inversion layer removal step.

[0100] <Placement process> As schematically shown in Figure 1, a workpiece layer PL is formed on the outermost layer of the substrate S, and in the placement process, a liquid film LC of the curable composition (A) is placed on the workpiece layer PL. Inkjet printing or spin coating is preferred as the placement method for the liquid film of the curable composition (A) on the substrate.

[0101] When using the inkjet method, it is preferable that droplets of the curable composition (A) be densely arranged on the substrate region opposite to the region where the recesses constituting the pattern on the mold are densely located. On the other hand, it is preferable that droplets of the curable composition (A) be sparsely arranged on the substrate region opposite to the region where the recesses constituting the pattern on the mold are sparsely located. As a result, the film (residual film) of the curable composition (A) formed on the substrate is controlled to have a uniform thickness regardless of the density of the pattern on the mold. When droplets of the curable composition (A) are discretely arranged using the inkjet method, it is preferable that all droplets combine with each other in the waiting step described later to form a substantially continuous liquid film. In this case, the spread process is omitted in the subsequent contact step, so the time required for the contact step is shortened.

[0102] In the present invention, the amount of curable composition (A) placed on the substrate is adjusted so that the thickness of the residual film formed in the contact process is 1 to 20 times the depth of the mold pattern. Preferably, it is 1 to 6 times, more preferably 1 to 4 times, and particularly preferably 2 to 4 times. For example, if the depth of the mold pattern is 50 nm, the residual film thickness (the thickness of the residual film sandwiched between the most convex part of the mold's irregularities and the substrate) is 50 nm to 1000 nm. Preferably, the residual film thickness is 50 nm to 300 nm, more preferably 50 nm to 200 nm, and particularly preferably 100 nm to 200 nm. The thicker the residual film thickness, the lower the possibility of damage to the mold pattern due to foreign matter that may be present between the mold and the substrate. Figure 2 schematically shows the fracture behavior of the irregularities pattern of the mold M due to foreign matter P sandwiched between the mold M and the substrate S. In the conventional technology, the uneven pattern of the mold M can be damaged if a foreign object P larger than the thickness of the residual film R is sandwiched between the mold. On the other hand, in the present invention, since the residual film R is thicker than in the conventional technology, even if a larger foreign object is present, the foreign object is embedded in the residual film, preventing damage to the uneven pattern. However, if the residual film thickness is too thick, it may become difficult to expose the substrate surface in the residual film etching process described later.

[0103] Furthermore, the height difference of the mold's irregularities should be less than or equal to the thickness of the remaining film. In this invention, because the remaining film is thick, the tolerance for height differences of the substrate surface irregularities is also high. For example, in the conventional technology, if the remaining film thickness is 20 nm, it is desirable to flatten the substrate until the height difference of the irregularities is less than 20 nm. On the other hand, in this invention, if the remaining film thickness is 200 nm, for example, the height difference of the substrate irregularities can be less than 200 nm.

[0104] <Standby process> Returning to Figure 1, in the present invention, a waiting step is provided between the arrangement step and the contact step to allow the solvent component (d) to volatilize. If the curable composition (A) does not contain component (d), the waiting step can be omitted. The amount of component (d) remaining in the liquid film F after the waiting step is preferably 10% by volume or less, assuming the total weight of components other than component (d) is 100% by volume. If the amount of component (d) remaining is greater than 10% by volume, the mechanical properties of the cured film may be reduced.

[0105] The waiting step is a process of waiting for a predetermined time after the placement step and before starting the contact step, where the predetermined time is, for example, 0.1 seconds to 600 seconds, preferably 10 seconds to 300 seconds. When an inkjet method is used for the placement step, it is preferable to wait until the droplets of discretely placed curable composition (A) combine with each other. If the waiting step is shorter than 0.1 seconds, the volatilization of component (d) may be insufficient. If the waiting step exceeds 600 seconds, productivity will be low.

[0106] During the waiting process, a baking process may be carried out to accelerate the volatilization of the solvent (d), by heating the substrate and the curable composition (A), or by ventilating the atmospheric gas around the substrate. The baking process is carried out at, for example, 30°C to 200°C, preferably 80°C to 150°C, and particularly preferably 80°C to 110°C. The heating time can be 10 seconds to 600 seconds. The baking process can be carried out using known heating devices such as hot plates and ovens.

[0107] During the waiting process, when solvent (d) evaporates, a liquid film consisting of components (a), (b), and (c) remains on the substrate. The average thickness of the liquid film after solvent (d) has evaporated (removed) is thinner than the liquid film immediately after the placement process, by the amount that solvent (d) has evaporated.

[0108] <Contact process> In the contact step, as schematically shown in Figure 1, the liquid film LC of the curable composition (A), from which the solvent (d) has been removed, is brought into contact with the mold M. The contact step includes a step of changing the state from one in which the curable composition (A) and the mold are not in contact to a state in which they are in contact, and a step of maintaining the state in which they are in contact. As a result, the liquid of the curable composition (A) fills the recesses of the fine patterns on the surface of the mold M, and this liquid becomes a liquid film that fills the fine patterns of the mold.

[0109] The contact process is preferably 0.1 seconds or more and 3 seconds or less, and particularly preferably 0.1 seconds or more and 1 second or less. If the contact process is shorter than 0.1 seconds, the spread and fill will be insufficient, and defects called unfilled defects tend to occur frequently. If the contact process is longer than 3 seconds, productivity will be low.

[0110] When the curing process includes a light irradiation step, the mold should be made of a light-transmitting material, taking this into consideration. Specifically, preferred materials for the mold include glass, quartz, light-transmitting resins such as PMMA and polycarbonate resin, transparent metal vapor-deposited films, flexible films such as polydimethylsiloxane, photocurable films, and metal films. However, when a light-transmitting resin is used as the mold material, a resin that does not dissolve in the components of the curable composition should be selected. Quartz is particularly preferred as a mold material because it has a low coefficient of thermal expansion and low pattern distortion.

[0111] The pattern formed on the surface of the mold has a height of, for example, 4 nm to 200 nm. The lower the height of the mold pattern, the less force is required to separate the mold from the cured film of the curable composition during the separation process, i.e., the release force can be reduced, thereby reducing the number of release defects remaining on the mold due to the pattern of the curable composition being torn off. Also, the impact when separating the mold can cause the pattern of the curable composition to elastically deform, causing adjacent pattern elements to come into contact, resulting in adhesion or damage. However, it is advantageous to have a pattern element height of approximately twice the width of the pattern element (aspect ratio of 2 or less) to avoid these problems. On the other hand, if the height of the pattern elements is too low, the processing accuracy of the workpiece layer on the substrate will be reduced.

[0112] The mold may be surface-treated before the contact process to improve its release properties from the curable composition (A). For example, surface treatment may involve applying a release agent to the mold surface to form a release agent layer. Examples of release agents to be applied to the mold surface include silicone-based release agents, fluorine-based release agents, hydrocarbon-based release agents, polyethylene-based release agents, polypropylene-based release agents, paraffin-based release agents, montan-based release agents, and carnauba-based release agents. Commercially available coating-type release agents, such as Daikin Industries, Ltd.'s Optool® DSX, can also be suitably used. The release agent may be used alone or in combination of two or more types. Among the above-mentioned release agents, fluorine-based and hydrocarbon-based release agents are particularly preferred.

[0113] In the contact process, the pressure applied to the curable composition (A) when the mold is brought into contact with the curable composition (A) is not particularly limited, but for example, it may be 0 MPa or more and 100 MPa or less. When the mold 106 is brought into contact with the curable composition (A), the pressure applied to the curable composition (A) is preferably 0 MPa or more and 50 MPa or less, more preferably 0 MPa or more and 30 MPa or less, and even more preferably 0 MPa or more and 20 MPa or less.

[0114] The contact process can be carried out under any of the following conditions: under an atmospheric atmosphere, under a reduced pressure atmosphere, or under an inert gas atmosphere. However, it is preferable to use a reduced pressure atmosphere or an inert gas atmosphere because it prevents the influence of oxygen and moisture on the curing reaction. Specific examples of inert gases used when carrying out the contact process under an inert gas atmosphere include nitrogen, carbon dioxide, helium, argon, various fluorocarbon gases, or mixtures thereof. When carrying out the contact process under a specific gas atmosphere, including an atmospheric atmosphere, the preferred pressure is between 0.0001 atmospheres and 10 atmospheres.

[0115] <Curing process> In the curing process, as schematically shown in Figure 1, the curable composition (A) is cured by irradiating it with irradiation light L as curing energy, thereby forming a cured film CC. In the curing process, for example, the curable composition (A) is irradiated with irradiation light L through a mold M. More specifically, the curable composition (A) filled in the fine pattern of the mold M is irradiated with irradiation light through the mold M. As a result, the curable composition (A) filled in the fine pattern of the mold M hardens, forming a cured film CC with a pattern.

[0116] The irradiation light is selected according to the sensitivity wavelength of the curable composition (A). Specifically, the irradiation light is appropriately selected from ultraviolet light, X-rays, or electron beams with a wavelength of 150 nm to 400 nm. It is particularly preferable that the mold is irradiated with ultraviolet light. This is because many commercially available curing aids (photopolymerization initiators) are compounds sensitive to ultraviolet light. Examples of light sources that emit ultraviolet light include high-pressure mercury lamps, ultra-high-pressure mercury lamps, low-pressure mercury lamps, deep-UV lamps, carbon arc lamps, chemical lamps, metal halide lamps, xenon lamps, KrF excimer lasers, ArF excimer lasers, and F2 lasers. However, ultra-high-pressure mercury lamps are particularly preferred as light sources that emit ultraviolet light. There may be one or more light sources. Furthermore, the entire area of ​​the curable composition (A) filled in the fine pattern of the mold may be irradiated with light, or only a portion of the area may be irradiated (limited to a specific area). Furthermore, the light irradiation may be performed intermittently multiple times over the entire surface of the substrate, or it may be performed continuously over the entire surface of the substrate. In addition, the first surface of the substrate may be irradiated with light during the second irradiation process, and a second surface of the substrate different from the first surface may be irradiated with light during the second irradiation process.

[0117] <Separation process> In the separation process, the mold M is separated from the cured film CC, as schematically shown in Figure 1. By separating the patterned cured film CC from the mold M, a self-supporting cured film CC with a pattern that is an inversion of the fine pattern of the mold M is obtained. Here, some of the cured film remains in the recesses of the patterned cured film CC. This film is called the residual film R.

[0118] The method for separating the mold from the patterned cured film is not limited to any particular conditions, as long as no part of the patterned cured film is physically damaged during separation. For example, the substrate may be fixed and the mold may be moved away from the substrate. Alternatively, the mold may be fixed and the substrate may be moved away from the mold. The mold may also be separated from the patterned cured film by moving both the mold and the substrate in opposite directions.

[0119] <Repeat> Through a series of steps (manufacturing process) including the arrangement step and separation step described above, a cured film can be obtained having a desired uneven pattern shape (a pattern shape that follows the uneven shape of the mold) at a desired position.

[0120] In the pattern formation method of the present invention, the process from placement to separation, or from contact to separation, can be repeated multiple times on the same substrate. This makes it possible to obtain a cured film having multiple desired patterns at desired locations on the substrate.

[0121] In this invention, an inversion process, detailed below, is performed to process a workpiece on a substrate using a cured film having a pattern shape obtained through a placement process and a separation process.

[0122] <Inversion layer formation process> As shown in Figure 3, an inversion layer H is formed on the cured film CC, which has a pattern shape formed after the arrangement and separation processes, so as to fill the recesses of the pattern.

[0123] The material for the inversion layer can be selected from silicon-based materials such as SiO2 and SiN, silicon-containing organic materials, metal oxide film materials such as TiO2 and Al2O3, and general metal materials.

[0124] For example, methods for forming an inversion layer using SiO2 include spin coating of spin-on-glass (SOG) materials and plasma CVD deposition using TEOS (Tetra Ethyl Ortho Silicate). Commercially available SOG materials include, but are not limited to, the following. Honeywell T-111, Tokyo Ohka Kogyo Co., Ltd. OCD T-12.

[0125] <Excess inversion layer removal process> In the inversion layer formation step, an inversion layer is also formed on the upper part of the protrusions of the patterned cured film CC (hereinafter, a portion of such an inversion layer will be referred to as the "excess inversion layer"). This excess inversion layer E needs to be removed until the upper part of the protrusions of the patterned cured film CC is exposed, as shown in Figure 3. Therefore, in the excess inversion layer removal step, the upper part of the inversion layer is removed so that the top surface of the protrusions of the unevenness formed on the cured film is exposed, while the inversion layer is embedded in the recesses of the unevenness formed on the cured film.

[0126] There are no particular limitations on the specific method for removing the excess inversion layer E, but known methods, such as dry etching, can be used. Known dry etching apparatus can be used for dry etching. The source gas during dry etching is appropriately selected depending on the elemental composition of the inversion layer. For example, a fluorocarbon gas such as those shown below can be used as the source gas during dry etching. CF4, CHF4, C2F6, C3F8, C4F8, C5F8, C4F6, CCl2F2, CBrF3 etc. Alternatively, halogen-based gases such as those shown below can be used as the source gas during dry etching. CCl4, BCl3, PCl3, SF6, Cl2 etc. These gases can also be used in mixtures.

[0127] <Residual film etching process> The remaining inversion layer H embedded in the pattern recess is used as a processing mask, and the cured film CC having the pattern shape is etched starting from the portion exposed by the excess inversion layer removal step. Etching continues until the surface of the workpiece layer PL on the substrate is exposed. This step forms a pattern (hereinafter referred to as the inversion pattern) in which the irregularities are reversed from those of the curable composition (A) cured film CC, as shown in Figure 1. The specific etching method is not particularly limited, but conventionally known methods, such as dry etching, can be used. Conventionally known dry etching apparatus can be used for dry etching. The source gas during dry etching is appropriately selected depending on the elemental composition of the resist layer, but gases containing oxygen atoms such as O2, CO, CO2, inert gases such as He, N2, Ar, and gases such as N2, H2, NH3 can be used. These gases can also be used in mixtures.

[0128] <Working layer processing process> Furthermore, in the present invention, as shown in Figure 3, the inverted pattern can be used as a processing mask to etch the workpiece layer PL on the substrate, thereby obtaining a workpiece layer having a patterned shape. Alternatively, the inverted pattern can be used as a processing mask for ion implantation of the workpiece layer. The etching of the workpiece layer may be carried out under the same conditions as the etching of the excess inverted layer, or under different conditions suitable for etching the workpiece layer. After processing the workpiece layer, the inverted pattern, which is the processing mask, may be removed.

[0129] [Product manufacturing method] The inverted pattern formed by the pattern formation method of the present invention can be used as is as a component of at least a part of various articles. Alternatively, the inverted pattern can be temporarily used as a processing mask for etching or ion implantation of the layer to be processed on the substrate. In the processing steps for the layer to be processed on the substrate, after etching or ion implantation is performed on the layer, the inverted pattern, which served as the processing mask, is removed. This allows for the manufacture of various articles.

[0130] Articles include electrical circuit elements, optical elements, MEMS, recording elements, sensors, or molds. Examples of electrical circuit elements include volatile or non-volatile semiconductor memories such as DRAM, SRAM, flash memory, and MRAM, as well as semiconductor elements such as LSI, CCD, image sensors, and FPGAs. If the layer to be processed is an insulating layer, it can be used as an interlayer insulating film included in the aforementioned semiconductor memories and semiconductor elements.

[0131] The processed layer having a pattern shape obtained through the arrangement process and the etching process can be used as an optical component (including when used as a part of an optical component) such as a diffraction grating or a polarizing plate to obtain an optical element. In such cases, the optical element can have at least a substrate and a processed layer having a pattern shape on this substrate. Examples of optical elements include microlenses, light guides, waveguides, anti-reflective coatings, diffraction gratings, polarizing elements, color filters, light-emitting elements, displays, and solar cells.

[0132] Examples of MEMS include DMDs, microfluidics, and electromechanical conversion elements. Examples of recording elements include optical discs such as CDs and DVDs, magnetic discs, magneto-optical discs, and magnetic heads. Examples of sensors include magnetic sensors, optical sensors, and gyroscopes. Examples of molds include molds for imprinting.

[0133] [Examples] To supplement the embodiments described above, more specific examples will be explained. The present invention will be described in more detail below with reference to examples, but the technical scope of the present invention is not limited to the examples described below.

[0134] <Estimation of the possibility of mold pattern damage> The number of particles remaining in a liquid curable composition (A) filtered using polyethylene resin filters and nylon resin filters was measured using a KS-19F liquid particle counter manufactured by Rion Co., Ltd. There were 117 particles / ml with a diameter of 70 nm or more, and 3 particles / ml with a diameter of 200 nm or more. The number of particles was lower for larger diameters. Based on these measurement results, the probability of mold damage due to remaining particles in the curable composition (A) is less than 1 / 39th when the remaining film thickness is 200 nm compared to when it is 70 nm, indicating that the probability of mold damage decreases as the remaining film thickness increases.

[0135] <Dry etching resistance: Inkjet method> The curable compositions (AC1), (AC2), (A1) to (A3) shown in Table 1 are prepared by the following procedure. Mix components (a) to (c) shown in Table 1. Next, add component (d) to a mixture of components (a) to (c) at a ratio of 20 vol. to make a total curable composition (A) at a ratio of 100 vol. The abbreviations used in Tables 1-4 are as follows: a1: 2-Phenylphenoxyethyl acrylate a2: Tricyclodecane dimethanol diacrylate a3:3-Phenoxybenzylacrylate a4:BPh43DA a5:Na13MDA b1: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide d1: Cyclohexanone d2: Benzyl acrylate [Table 1]

[0136] A 300nm thick spin-on-glass film (SOG, Honeywell T-111) was deposited on a silicon substrate as the workpiece layer, and a 5nm thick adhesion layer, as described in Patent Document 4, was deposited on the surface of the T-111 layer as an adhesion layer. The curable compositions (AC1), (AC2), (A1) to (A3) shown in Table 1 were used from the placement process to the separation process. The mold pattern height, i.e., the thickness of the inversion layer, was set to 50nm, and the remaining film thickness was set to 200nm. An inkjet method was used for the placement process, and the waiting process was left at room temperature for 10 minutes.

[0137] Next, the cured films of the curable compositions (AC1), (AC2), and (A1) to (A3) are subjected to the inversion layer formation process and the workpiece layer processing process. Honeywell T-111 is used as the inversion layer, the same as for the workpiece layer. The excess inversion layer removal process and the residual film etching process are performed using a ULVAC high-density plasma etching system NE-550, with CF4 / CHF3 mixed gas plasma and O2 / Ar mixed gas plasma, respectively.

[0138] In the workpiece processing process, Table 1 indicates cases where the T-111 layer, which is the workpiece layer, can be processed until the surface of the silicon substrate is exposed (marked with ○), and cases where defects occur, such as the disappearance of the cured film before exposure (marked with ×).

[0139] These results demonstrate that the inversion process of the present invention using a curable composition with an OP of 3.00 or less can achieve the same processing performance as a conventional inversion process using a spin-on-carbon (SOC) layer.

[0140] <Dry etching resistance: Spin coating method> The curable compositions (AC3), (AC4), and (A4) to (A6) shown in Table 2 are prepared by the following procedure. Mix components (a) to (c) shown in Table 2. Next, add component (d) to 10% by volume of the mixture of components (a) to (c) so that component (d) becomes 90% by volume to make a total curable composition (A) of 100% by volume. [Table 2]

[0141] A 300 nm thick spin-on-glass film (SOG, Honeywell T-111) is deposited on a silicon substrate as the workpiece layer, and a 5 nm thick adhesion layer, as described in Patent Document 4, is deposited on the surface of the T-111 layer as an adhesion layer. On the substrate, the curable compositions (AC3), (AC4), (A4) to (A6) shown in Table 2 are carried out from the placement process to the separation process. The mold pattern height, i.e., the thickness of the inversion layer, is set to 50 nm, and the remaining film thickness is set to 200 nm. A spin coating method is used for the placement process, and the waiting process is left at room temperature for 10 minutes.

[0142] Next, the cured films of the curable compositions (AC3), (AC4), and (A4) to (A6) are subjected to the inversion layer formation process and the workpiece layer processing process. Honeywell T-111 is used as the inversion layer, the same as for the workpiece layer. The excess inversion layer removal process and the residual film etching process are performed using a ULVAC high-density plasma etching system NE-550, with CF4 / CHF3 mixed gas plasma and O2 / Ar mixed gas plasma, respectively.

[0143] Table 2 shows cases where the T-111 layer, which is the workpiece layer, can be processed until the surface of the silicon substrate is exposed (indicated by ○), and cases where defects occur, such as the disappearance of the cured film before exposure (indicated by ×).

[0144] These results demonstrate that the inversion process of the present invention using a curable composition with an OP of 3.00 or less can achieve the same processing performance as a conventional inversion process using a spin-on-carbon (SOC) layer.

[0145] <Volatile: Inkjet method> The curable compositions (AC5), (A7) to (A10) shown in Table 3 are prepared by the following procedure. Mix components (a) to (c) shown in Table 3. Next, add component (d) to a mixture of components (a) to (c) at a ratio of 20 vol. to make a total curable composition (A) at a ratio of 100 vol. [Table 3]

[0146] A 300nm thick spin-on-glass film (SOG, Honeywell T-111) is deposited on a silicon substrate as the workpiece layer, and a 5nm thick adhesion layer, as described in Patent Document 4, is deposited on the surface of the T-111 layer as an adhesion layer. On the substrate, the curable compositions (AC5), (A7) to (A10) shown in Table 3 are carried out from the placement step to the waiting step. In the waiting step, a bake step is carried out on a hot plate at 80°C for 60 seconds. The film thickness of the curable composition before and after the bake step is measured, and if the film thickness is reduced by 10nm or more, it is marked with ×, and if the film thickness is reduced by less than 10nm, it is marked with ○, as shown in Table 3.

[0147] This result demonstrates that polymerizable compounds (a) with a vapor pressure of 0.001 mmHg or less at 80°C can prevent volatilization during the baking process.

[0148] <Volatility: Spin Coating Method> The curable compositions (AC6), (A11) to (A14) shown in Table 4 were prepared using the following procedure. Components (a) to (c) shown in Table 4 were mixed. Next, component (d) was added to 10% by volume of the mixture of components (a) to (c) so that component (d) constituted 90% by volume, resulting in a total curable composition (A) of 100% by volume. [Table 4]

[0149] A 300nm thick spin-on-glass film (SOG, Honeywell T-111) is deposited on a silicon substrate as the workpiece layer, and a 5nm thick adhesion layer, as described in Patent Document 4, is deposited on the surface of the T-111 layer as an adhesion layer. On the substrate, the curable compositions (AC6), (A11) to (A14) shown in Table 4 are carried out from the placement step to the waiting step. In the waiting step, a bake step is carried out on a hot plate at 80°C for 60 seconds. The film thickness of the curable composition before and after the bake step is measured, and if the film thickness is reduced by 10nm or more, it is marked with ×, and if the film thickness is reduced by less than 10nm, it is marked with ○, as shown in Table 4.

[0150] This result demonstrates that polymerizable compounds (a) with a vapor pressure of 0.001 mmHg or less at 80°C can prevent volatilization during the baking process.

[0151] The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0152] LC: Liquid film, M: Mold, CC: Cured film, R: Residual film, PL: Workpiece layer, E: Excess inversion layer, H: Inversion layer

Claims

1. A placement step of placing a curable composition (A) containing at least a polymerizable compound (a) on a substrate, After the arrangement step, a contact step is performed in which the curable composition (A) on the substrate and the mold having irregularities are brought into contact, After the contact step, a curing step is performed to cure the curable composition (A) to form a cured film, A pattern forming method comprising, after the curing step, a separation step of separating the curable composition (A) and the mold, The thickness of the residual film sandwiched between the most convex part of the irregularities of the mold and the substrate is 50 nm or more, and the height difference of the irregularities of the mold is less than or equal to the thickness of the residual film. The pattern forming method further includes, A forming step of forming an inversion layer on the cured film on top of the irregularities transferred from the mold, A removal step of removing the upper layer of the inversion layer so as to expose the top surface of the convex portion of the unevenness formed on the hardened film, with the inversion layer embedded in the concave portion of the unevenness formed on the hardened film. An etching step in which the inversion layer embedded in the recess is used as a mask and the cured film is etched to the substrate surface to form an inversion pattern, A pattern forming method characterized by having the following features.

2. The pattern forming method according to claim 1, characterized in that, in the arrangement step, a plurality of droplets of the curable composition (A) are discretely arranged on the substrate using an inkjet method.

3. The curable composition (A) comprises at least a solvent (d), The polymerizable compound (a) comprises at least a compound having an aromatic structure, an aromatic heterocyclic structure, or an alicyclic structure. The curable composition (A) has a viscosity of 2 mPa·s or more and 60 mPa·s or less at 23°C. The curable composition (A), in its solvent-free state, has a viscosity of 30 mPa·s or more and 10,000 mPa·s or less at 23°C. The content of the solvent relative to the total curable composition (A) is 70% by volume or more and 95% by volume or less. The pattern forming method according to feature 2.

4. The curable composition (A) comprises at least a solvent (d), The spin coating method is used in the aforementioned arrangement step. The pattern forming method according to feature 1.

5. N is the total number of atoms in the molecule, and N is the number of carbon atoms in the molecule. Ｃ , the number of oxygen atoms in the molecule is N Ｏ In that case, The polymerizable compound (a), which may contain multiple types, has a N / (N) ratio for each molecule. Ｃ -N Ｏ The pattern forming method according to any one of claims 1 to 4, characterized in that the Onishi parameter (OP), which is a mole fraction weighted average of the values, is 2.00 or more and 3.00 or less.

6. The pattern forming method according to any one of claims 1 to 5, characterized in that the vapor pressure at 80°C of the polymerizable compound (a), which may contain multiple types, is all 0.001 mmHg or less.

7. The pattern forming method according to any one of claims 1 to 6, characterized in that the outermost layer to be processed on the substrate is an insulating film containing at least silicon atoms.

8. The pattern forming method according to any one of claims 1 to 7, further comprising a waiting step of waiting for a predetermined time after the arrangement step and before starting the contact step.

9. A step of forming a pattern of a curable composition on a substrate using the pattern forming method described in any one of claims 1 to 8, A step of processing the substrate on which the pattern has been formed in the above step, A method for manufacturing articles, characterized by having a substrate and manufacturing an article from the processed substrate.

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