Curable composition, film formation method, pattern formation method, and article production method

Abstract

Provided is a curable composition comprising a polymerizable compound (a), a photopolymerization initiator (b), and a solvent (d), wherein: the content of the solvent (d) with respect to the entire curable composition is more than 5 vol% but not more than 95 vol%; the polymerizable compound (a) contains an N-vinyl compound (a1), a monofunctional acrylate compound (a2), and a polyfunctional (meth)acrylate compound (a3); the molecular weight of the N-vinyl compound (a1) is 150-300; and the content of the N-vinyl compound (a1) is at least 5 parts by mass but less than 45 parts by mass with respect to 100 parts by mass of the total amount of the polymerizable compound (a).

Description

Curable composition, film formation method, pattern formation method, and article manufacturing method

[0001] This disclosure relates to a curable composition, a film-forming method, a pattern-forming method, and a method for manufacturing articles.

[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 a few nanometers on a substrate.

[0003] An example of a pattern formation method using imprint technology is described below. First, liquid curable material is discretely dropped (placed) onto the pattern formation area on the substrate. The droplets of curable composition placed on the pattern formation area spread on the substrate. This phenomenon is called press spreading. Next, the mold is brought into contact with (pressed against) the curable composition on the substrate. As a result, the droplets of curable composition spread throughout the entire 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 curable composition is formed. In this specification, "residual film" refers to the cured film remaining between the recesses (protrusions of the mold pattern) of the cured film of the curable composition and the substrate.

[0004] Also, in the photolithography process for manufacturing semiconductor devices, it is also necessary to planarize the substrate. For example, in extreme ultraviolet lithography (EUV), which is a photolithography technology attracting attention in recent years, as the miniaturization progresses, the depth of focus at which the projected image is formed becomes shallower. Therefore, the surface roughness of the substrate to which the curable composition is supplied must be suppressed to several tens of nanometers or less. In imprint technology as well, flatness comparable to that of EUV is required to improve the filling property and line width accuracy of the curable composition. As a planarization technique, a technique for obtaining a flat surface is known in which droplets of a curable composition corresponding to the unevenness are discretely dropped onto a substrate having unevenness, and the curable composition is cured in a state where a mold having a flat surface is brought into contact with the curable composition.

[0005] In a pattern formation method or planarization technique using imprint technology, when the mold is brought into contact in a state where the droplets dropped on the substrate do not contact each other, the bubbles entrapped between the mold, the substrate, and the curable composition become larger. Therefore, it takes a long time until such bubbles diffuse and disappear in the mold or the substrate, which is one of the factors reducing productivity (throughput). In Patent Document 1, a technique for bonding droplets containing a curable composition to each other before bringing the curable composition on the substrate into contact with the mold by diluting the curable composition with a solvent has been proposed.

[0006] Also, if the glass transition temperature of the cured film is sufficiently higher than the temperature of the cured film on the substrate (at the time of mold release) when the mold is separated from the cured curable composition (cured film) on the substrate, the cured product at the time of mold release shows a strong glassy state, that is, high mechanical strength. Therefore, in this case, there is a tendency that the pattern is less likely to collapse or break due to the impact of mold release.

[0007] Furthermore, when processing a substrate using a pattern obtained by imprint technology as a mask, a process called an inversion process can be applied. When the inversion process is applied, a pattern higher than the pattern height of the mold can be formed through the steps described below. Patent Document 2 discloses the following inversion process steps. An inversion layer is formed on the concavo-convex pattern (inversion layer formation step), and the inversion layer material is embedded in the concave portions. The inversion layer material is also laminated on the upper portions of the convex portions of the concavo-convex pattern, becoming an excess inversion layer. The excess inversion layer is removed so as to expose the top surfaces of the convex portions of the concavo-convex pattern of the cured film of the curable composition (excess inversion layer removal step), and the inversion layer embedded in the concave portions is exposed. The exposed inversion layer is used as a mask, and the remaining film of the concavo-convex pattern and further the carbon-based material layer thereunder are etched to form an inverted pattern (lower layer etching step). In the conventional inversion process, it is necessary to form a layer having higher dry etching resistance than the curable composition, such as a spin-on carbon (SOC) layer, under the curable composition for imprint. In addition, it is also necessary to minimize the remaining film of the cured film having low dry etching resistance. However, when minimizing the remaining film, if foreign matter larger than the remaining film thickness is sandwiched between the mold and the lower layer, the mold may be damaged. In order to avoid this damage to the mold, it is conceivable to increase the thickness of the remaining film so that the foreign matter is included in the remaining film.

[0008] Patent Document 1 describes that a monofunctional and / or polyfunctional acrylate compound having an aromatic structure, an aromatic heterocyclic structure or an alicyclic structure is contained in the curable composition. By curing this composition in the presence of a photo radical generator, it is possible to form a cured film having high dry etching resistance and a high glass transition temperature.

[0009] Japanese Unexamined Patent Application Publication No. 2022-188736, Japanese Unexamined Patent Application Publication No. 2016-162862, US Patent Application Publication No. 2020 / 0286740, Japanese Patent Application Publication No. 2009-503139

[0010] Proc. SPIE 11324-11 (2020)

[0011] However, increasing the thickness of the residual film results in areas where curing is insufficient with conventional exposure levels, lowering the glass transition temperature in those areas and increasing the occurrence of pattern collapse. On the other hand, increasing the exposure level to ensure sufficient curing increases the curing time and reduces throughput. Increasing the content of the polyfunctional acrylate compound can be considered to improve the curing speed, but this method increases the viscosity of the curable composition, worsening its packing ability and reducing throughput.

[0012] This disclosure has been made in view of the problems of the prior art and provides a new technology relating to curable compositions.

[0013] According to one aspect of the present disclosure, a curable composition is provided comprising a polymerizable compound (a), a photopolymerization initiator (b), and a solvent (d), wherein the content of the solvent (d) relative to the total curable composition is greater than 5% by volume and 95% by volume or less, the polymerizable compound (a) contains an N-vinyl compound (a1), a monofunctional acrylate compound (a2), and a polyfunctional (meth)acrylate compound (a3), the molecular weight of the N-vinyl compound (a1) is 150 or more and 300 or less, and the content of the N-vinyl compound (a1) is 5 parts by mass or more and less than 45 parts by mass per 100 parts by mass of the total amount of the polymerizable compound (a).

[0014] Further purposes or other aspects of this disclosure will be revealed by embodiments described below with reference to the accompanying drawings.

[0015] This disclosure provides, for example, a new technology relating to curable compositions. Other features and advantages of the technical ideas derived from this disclosure will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are given the same reference numeral.

[0016] The attached drawings are included in the specification and constitute part thereof, illustrating embodiments in this disclosure and used together with the description to explain the technical ideas derived from this disclosure. These include: a diagram illustrating a pattern formation method (film formation method); a diagram illustrating the flow behavior of droplets of a curable composition during the waiting process; a diagram comparing the contact process in the prior art with the contact process in the embodiment; a diagram illustrating the advantages of thickening the residual film; and a diagram illustrating the inversion process.

[0017] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the scope of the claims. While the embodiments describe multiple features, not all of these features are necessary, and the features may be combined in any way. Furthermore, in the attached drawings, identical or similar configurations are given the same reference numerals, and redundant descriptions are omitted.

[0018] This disclosure provides, for example, a novel technology relating to a curable composition for inkjet printing that includes a solvent. The inventors have discovered a technology that enables the curable composition to have low viscosity and a high curing rate when the solvent is removed, and furthermore, to achieve both a high glass transition temperature and high dry etching resistance in the cured film.

[0019] In order to achieve a curable composition with low viscosity and a high curing rate during solvent removal, while simultaneously ensuring a high glass transition temperature and high dry etching resistance in the cured film, several challenges existed.

[0020] The first challenge is achieving both low viscosity and high curing speed. Low viscosity and high curing speed are basically in a trade-off relationship, making it difficult to achieve both. For example, when a curable composition is composed of acrylate compounds, polyfunctional acrylate compounds that generally have high curing speeds are high viscosity, so improving the curing speed requires a significant increase in viscosity.

[0021] The second challenge is achieving both low viscosity, a high glass transition temperature, and high dry etching resistance. In particular, low viscosity and a high glass transition temperature are basically in a trade-off relationship, and achieving both is difficult, similar to the first challenge. For example, when the curable composition is composed of acrylate compounds, polyfunctional acrylate compounds that generally have a high glass transition temperature are highly viscous, so increasing the glass transition temperature involves a significant increase in viscosity.

[0022] The inventors conducted further investigations to address these issues. As a result, they found that including an N-vinyl compound with a molecular weight of 150 to 300 and a monofunctional acrylate compound in the curable composition is effective in solving the problems. Specifically, it was found that the curing speed of the N-vinyl compound, which has a low curing speed on its own, is significantly improved when it is combined with a monofunctional acrylate compound. At the same time, it was found that the glass transition temperature also shows a greater-than-expected improvement when the N-vinyl compound and monofunctional acrylate compound are combined.

[0023] Curable Composition The curable composition (A) in this disclosure is, for example, a curable composition for inkjet printing and may include a polymerizable compound (a), a photopolymerization initiator (b), and a solvent (d). In one example, the content of solvent (d) relative to the total curable composition (A) is greater than 5% by volume and 95% by volume or less. The polymerizable compound (a) contains at least an N-vinyl compound (a1), a monofunctional acrylate compound (a2), and a polyfunctional (meth)acrylate compound (a3). The molecular weight of compound (a1) may be 150 or more and 300 or less. The content of N-vinyl compound (a1) may be 5 parts by mass or more and less than 45 parts by mass per 100 parts by mass of the total amount of polymerizable compound (a). The content of polyfunctional (meth)acrylate compound (a3) ​​in polymerizable compound (a) may be 0 parts by mass or more and 55 parts by mass per 100 parts by mass of the total amount of polymerizable compound (a). The curable composition (A) in this disclosure may further contain a nonpolymerizable compound (c).

[0024] Furthermore, in this specification, a cured film means a film obtained by polymerizing and curing a curable composition (A) on a substrate. The shape of the cured film is not particularly limited and may have a pattern shape on its surface.

[0025] <Polymerizable compound (a)> Polymerizable compound (a) is a compound that reacts with radicals generated from the photopolymerization initiator (component (b)) and forms a film made of a polymer compound through a chain reaction (radical polymerization reaction).

[0026] The polymerizable compound (a) of this disclosure is a radical polymerizable compound and contains at least two types: an N-vinyl compound (a1) and a monofunctional acrylate compound (a2). The polymerizable compound (a) may consist only of the two polymerizable compounds, N-vinyl compound (a1) and monofunctional acrylate compound (a2), or it may contain other polymerizable compounds. Hereinafter, N-vinyl compound (a1) and monofunctional acrylate compound (a2) may be simply referred to as "compound (a1)" and "compound (a2)," respectively. Also, the polymerizable compound (a) may be referred to as "component (a)."

[0027] Dry etching rate V of the organic compound, total number of atoms N in the organic compound, total number of carbon atoms N 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 ) Equation (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 2 describes a technique for obtaining a photocurable composition with high dry etching resistance by using a polymerizable compound component with a small OP.

[0028] According to equation (1) above, organic compounds with a high concentration of oxygen atoms in the molecule, or with fewer aromatic or alicyclic structures, have a larger OP (Oxidation Factor) and a faster dry etching rate.

[0029] In the present disclosure, the OP of component (a) is set to 1.80 or more and 2.70 or less. More preferably, it is 2.00 or more and 2.60 or less, and particularly preferably, it is 2.30 or more and 2.60 or less. By setting it to 2.70 or less, the cured film of the curable composition (A) has high dry etching resistance. By setting it to 1.80 or more, after processing the underlying layer with the cured film of the curable composition (A), it becomes easy to remove the cured film of the curable composition (A). When component (a) is composed of a plurality of types of polymerizable compounds a １ , a ２ , ···, a ｎ , the OP is calculated as a weighted average value (mole fraction weighted average value) based on the mole fraction as shown in the following formula (2). Here, OP ｎ is the OP of component a ｎ , and n ｎ is the mole fraction of component a ｎ in the whole component (a). In order to set the OP of component (a) to be 1.80 or more and 2.70 or less, it is preferable to contain at least component (a) a compound having two or more cyclic structures, at least one of which is an aromatic or aromatic heterocyclic structure.

[0030] <N-vinyl compound (a1): polymerizable compound> In the present disclosure, the N-vinyl compound (a1) has a molecular weight of 150 or more and 300 or less. Hereinafter, the N-vinyl compound (a1) may be described as "component (a1)". The boiling point of component (a1) and the effective viscosity in the curable resin composition are generally correlated with the molecular weight. Therefore, when the molecular weight of component (a1) is 150 or more, it has a sufficiently high boiling point for use as an imprint curable composition, and volatilization can be suppressed. The molecular weight of component (a1) is preferably 170 or more, and more preferably 190 or more. Further, when the molecular weight of component (a1) is 300 or less, it becomes possible to achieve a low viscosity in the curable composition during solvent removal.

[0031] As the compound (a1), from the viewpoint of improving dry etching resistance, a monofunctional acrylate compound having two or more cyclic structures, at least one of which is an aromatic, aromatic heterocyclic structure or an alicyclic structure, is preferable.

[0032] Examples of cyclic structures include aromatic structures, aromatic heterocyclic structures, and alicyclic structures.

[0033] The aromatic structure preferably has 6 to 22 carbon atoms, more preferably 6 to 18, and even more preferably 6 to 10. Specific examples of aromatic rings include: benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, phenalene ring, fluorene ring, benzocyclooctene ring, acenaphthylene ring, biphenylene ring, indene ring, indan ring, triphenylene ring, pyrene ring, chrysene ring, perylene ring, and tetrahydronaphthalene ring.

[0034] Of the aromatic rings mentioned above, benzene rings or naphthalene rings are preferred, and benzene rings are more preferred. The aromatic rings may have a structure in which multiple rings are linked together, for example, biphenyl rings or bisphenyl rings.

[0035] The aromatic heterocyclic structure preferably has 1 to 12 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 5. Specific examples of aromatic heterocyclic structures include: 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, quinoridine ring, isoquinoline ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinazoline ring, sinnoline ring, carbazole ring, acridine ring, phenazine ring, phenothiazine ring, phenoxatiin ring, and phenoxazine ring.

[0036] As for the alicyclic structure, the number of carbon atoms is preferably 3 or more, more preferably 4 or more, and even more preferably 6 or more. Furthermore, as for the alicyclic structure, 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, and adamantane ring.

[0037] Specific examples of compound (a1) include, for example, N-vinylcarbazole, N-vinylphthalimide, N-vinyl-1,8-naphthalimide, or N-vinylindole derivatives and N-vinylcarbazole derivatives represented by the following formula. However, compound (a1) is not limited to these. Among these, N-vinylcarbazole, N-vinylphthalimide, and N-vinyl-1,8-naphthalimide are preferred from the viewpoint of achieving both a high curing rate in the curable composition, a high glass transition temperature in the cured film, and high dry etching resistance. N-vinylcarbazole and N-vinyl-1,8-naphthalimide are more preferred from the viewpoint of a high boiling point. Furthermore, N-vinylcarbazole is even more preferred from the viewpoint of achieving an extremely high curing rate. Formula (1A) N-vinylindole derivative In the formula, R １ ~R ６ Each of these is independently a hydrogen atom, a C1-C10 alkyl group, an optionally substituted C6-C10 aryl group, an optionally substituted C2-C10 vinyl group, or an optionally substituted C2-C10 ethynyl group. However, R １ ~R ６ At least two adjacent groups may be bonded to each other to form a ring. Among N-vinylindole derivatives, in general formula (1A), R １ ~R６ Specific examples of which are a vinyl group or an ethynyl group having two carbon atoms include the following: Formula (2A) N-vinylcarbazole derivative In the formula, R １ ~R ８ Each of these is independently a hydrogen atom, an optionally substituted C1-C10 alkyl group, an optionally substituted C6-C10 aryl group, an optionally substituted C2-C10 vinyl group, or an optionally substituted C2-C10 ethynyl group. However, R １ ~R ８ At least two adjacent groups may be bonded to each other to form a ring. Among the N-vinylcarbazole derivatives, in general formula (2A), R １ ~R ８ Specific examples of which are a vinyl group or an ethynyl group having two carbon atoms include the following:

[0038] In this disclosure, the content of compound (a1) is 5 parts by mass or more and less than 45 parts by mass per 100 parts by mass of the total amount of polymerizable compound (a). Preferably, it is 7 parts by mass or more and less than 40 parts by mass, and more preferably 10 parts by mass or more and less than 35 parts by mass. By having a compound (a1) content of 5 parts by mass or more, it is possible to achieve both low viscosity, high curing speed, and high glass transition temperature. On the other hand, when the compound (a1) content is 45 parts by mass or more, separation and precipitation of compound (a1) in the curable composition after solvent removal tend to make it difficult to obtain a liquid film and cured film with a uniform composition.

[0039] <Monofunctional Acrylate Compound (a2): Polymerizable Compound> Compound (a2) is a monofunctional acrylate compound. A monofunctional acrylate compound is a compound having one acryloyl group. In particular, as component (a2), from the viewpoint of improving dry etching resistance, a monofunctional acrylate compound having two or more cyclic structures, at least one of which is aromatic, aromatic heterocyclic, or alicyclic, can be suitably used. As for the cyclic structure, those similar to those described above can be suitably used.

[0040] Specific examples of monofunctional acrylate compounds (a2) having a boiling point of 250°C or higher and having two or more cyclic structures, at least one of which is aromatic, aromatic heterocyclic, or alicyclic, include, but are not limited to, the following.

[0041] 3-Phenoxybenzylacrylate (mPhOBzA, OP2.54, boiling point 367.4°C, molecular weight 254.3), 1-Naphthyl acrylate (NaA, OP2.27, boiling point 317°C, molecular weight 198), 2-Phenylphenoxyethyl acrylate (PhPhOEA, OP2.57, boiling point 364.2°C, molecular weight 268.3), 1-Naphthylmethyl acrylate (Na1MA, OP2.33, boiling point 342.1°C, molecular weight 212.2), 2-Naphthylmethyl acrylate (Na2MA, OP2.33, boiling point 342.1°C, molecular weight 212.2), DPhPA (OP2.38, boiling point 354.5°C, molecular weight 266.3) as shown in the following formula, PhBzA (OP2.29, boiling point 350.4°C, molecular weight 238.3) as shown in the following formula, FLMA (OP 2.20, boiling point 349.3°C, molecular weight 250.3) as shown in the following formula, ATMA (OP2.13, boiling point 414.9°C above 50 nm, molecular weight 262.3), as shown in the formula below. DNaMA (OP 2.00, boiling point 489.4°C, molecular weight 338.4), as shown in the formula below. The following formula (a2-1) (OP2.40, boiling point 333.4°C, molecular weight 199.2), The following formula (a2-2) (OP2.40, boiling point 333.4°C, molecular weight 199.2), The following formula (a2-3) (OP2.71, boiling point 333.7°C, molecular weight 244.3), The following formula (a2-4) (OP2.73, boiling point 333.7°C, molecular weight 258.3), The following formula (a2-5) (OP2.71, boiling point 319.2°C, molecular weight 262.3), The following formula (a2-6) (OP2.71, boiling point 336.9°C, molecular weight 244.3), The following formula (a2-7) (OP3.00, boiling point 370.9°C, molecular weight 274.4), The following formula (a2-8) (OP3.00, boiling point 376.4°C, molecular weight 274.4), The following formula (a2-9) (OP3.00, boiling point 379.4°C, molecular weight 288.4), The following formula (a2-10) (OP2.33, boiling point 360.8°C, molecular weight 252.3), The following formula (a2-11) (OP2.54, boiling point 371.5°C, molecular weight 254.3), The following formula (a2-12) (OP2.57, boiling point 381.2°C, molecular weight 268.3), The following formula (a2-13) (OP2.57, boiling point 381.8°C, molecular weight 268.3), The following formula (a2-14) (OP2.50, boiling point 487.4°C, molecular weight 374.4),

[0042] Other compounds (a2) in this disclosure include, but are not limited to, the following: phenoxyethyl acrylate, phenoxy-2-methylethyl acrylate, phenoxyethoxyethyl acrylate, 3-phenoxy-2-hydroxypropyl acrylate, 2-phenylphenoxyethyl acrylate, 4-phenylphenoxyethyl acrylate, 3-(2-phenylphenyl)-2-hydroxypropyl acrylate, EO-modified p-cumylphenol acrylate, 2-bromophenoxyethyl acrylate, 2,4-dibromophenoxyethyl acrylate, 2,46-Tribromophenoxyethyl acrylate, EO-modified phenoxyacrylate, PO-modified phenoxyacrylate, polyoxyethylene nonylphenyl ether acrylate, isobornyl acrylate, 1-adamantyl acrylate, 2-methyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl acrylate, bornyl acrylate, tricyclodecanyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, cyclohexyl acrylate, 4-butylcyclohexyl acrylate, acrylic Roylmorpholine, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, amyl acrylate, isobutyl acrylate, t-butyl acrylate, pentyl acrylate, isoamyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl Acrylate, isodecyl acrylate, undecyl acrylate, dodecyl acrylate, lauryl acrylate, stearyl acrylate, isostearyl acrylate, benzyl acrylate, tetrahydrofurfuryl acrylate, butoxyethyl acrylate, ethoxydiethylene glycol acrylate, polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, methoxyethylene glycol acrylate, ethoxyethyl acrylate, methoxypolyethylene glycol acrylate, methoxypolypropylene Pylene glycol acrylate, diacetone acrylamide, isobutoxymethyl acrylamide, N,N-dimethylacrylamide, t-octylacrylamide, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, 7-amino-3,7-dimethyloctyl acrylate, N,N-diethylacrylamide, N,N-dimethylaminopropyl acrylamide, 1- or 2-naphthyl acrylate, 1- or 2-naphthylmethyl acrylate, 3- or 4-phenoxybenzyl acrylate, cinovabenzyl acrylate.

[0043] Examples of commercially available compounds (a2) mentioned above include, but are not limited to, the following: Arronix® M101, M102, M110, M111, M113, M117, M5700, TO-1317, M120, M150, M156 (all manufactured by Toagosei), MEDOL10, MIBDOL10, 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 Co., Ltd.), 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 Co., Ltd.), 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).

[0044] It is well known that compound (a2) exhibits a high radical polymerization reaction rate (curing rate) even when used alone. However, the inventors have discovered that the curing rate is further improved when it is present with N-vinyl compound (a1). This is presumed to be due to the following properties: • In the radical polymerization reaction between N-vinyl compound (a1) and compound (a2), the radical of compound (a1) is more reactive with compound (a2) than with compound (a1). • Furthermore, the radical of compound (a2) is more reactive with compound (a1) than with compound (a2). In other words, it is thought that an extremely high curing rate can be achieved when conditions are favorable for alternating copolymerization reactions to occur in the presence of compound (a1) and compound (a2).

[0045] Furthermore, a cured product of a curable composition containing an N-vinyl compound (a1) and a monofunctional acrylate compound (a2) exhibits a remarkable improvement in the glass transition temperature. This effect is presumed to be due to the ease with which alternating copolymerization reactions occur in the presence of the aforementioned compounds (a1) and (a2). In other words, monofunctional acrylate compounds (a2), which have a low glass transition temperature, are less likely to be incorporated into polymer chains in multiple consecutive sequences. By being incorporated alternately with compound (a1), the movement of the polymer chains is further suppressed. This is thought to be the reason for the remarkable improvement in the glass transition temperature. Therefore, in the curable composition of this disclosure, by coexisting a monofunctional acrylate compound (a2), which generally has low viscosity but a low glass transition temperature, with an N-vinyl compound (a1), it becomes possible to achieve both a higher-than-expected glass transition temperature and low viscosity.

[0046] To maximize the glass transition temperature improvement effect described above, it is preferable that both the N-vinyl compound (a1) and the monofunctional acrylate compound (a2) have at least one aromatic, aromatic heterocyclic structure in their structure. This is preferable because the presence of aromatic, aromatic heterocyclic structures in compounds (a1) and (a2) allows π interactions to function effectively, suppressing the movement of polymer chains and resulting in a more pronounced improvement in the glass transition temperature.

[0047] In this disclosure, the content of compound (a2) is preferably 10 parts by mass or more and 80 parts by mass or less per 100 parts by mass of the total amount of polymerizable compound (a). Preferably, it is 15 parts by mass or more and 75 parts by mass or less, and more preferably 20 parts by mass or more and 70 parts by mass or less. If the content of compound (a2) is less than 10 parts by mass, it tends to be difficult to achieve both low viscosity and a high glass transition temperature, which is undesirable. Also, if the content of compound (a2) is more than 80 parts by mass, it is difficult to achieve a high curing rate and a high glass transition temperature, which is undesirable.

[0048] <Polyfunctional (meth)acrylate compound (a3): Polymerizable compound> In this disclosure, component (a) may contain a polyfunctional (meth)acrylate compound (a3) ​​having two or more acryloyl groups or methacryloyl groups.

[0049] The boiling point of compound (a3) ​​generally correlates with its molecular weight. For this reason, compound (a3) ​​preferably has a molecular weight of 200 or more, more preferably 240 or more, and even more preferably 250 or more. 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 polymerizable compound (a) in this disclosure.

[0050] As compound (a3), from the viewpoint of improving dry etching resistance, a monofunctional acrylate compound having two or more cyclic structures, at least one of which is aromatic, aromatic heterocyclic, or alicyclic, is preferred. As the cyclic structure, the same as those described above can be suitably used.

[0051] Specific examples of polyfunctional acrylate compounds (a3) ​​having a boiling point of 250°C or higher and having two or more cyclic structures, at least one of which is aromatic, aromatic heterocyclic, or alicyclic, include, but are not limited to, the following: BPh44DA (OP2.63, boiling point 444°C, molecular weight 322.3) shown in the following formula. BPh43DA (OP2.63, boiling point 439.5°C, molecular weight 322.3), as shown in the formula below. DPhEDA (OP2.63, boiling point 410°C, molecular weight 322.3) as shown in the following formula, BPMDA (OP 2.68, boiling point 465.7°C, molecular weight 364.4) as shown in the following formula, Na13MDA (OP2.71, boiling point 438.8°C, molecular weight 296.3) as shown in the formula below, The following formula (a3-1) (OP 2.85, boiling point 438.8°C, molecular weight 296.3), The following formula (a3-2) (OP 2.71, boiling point 438.8°C, molecular weight 296.3), The following formula (a3-3) (OP2.87, boiling point 421.0°C, molecular weight 338.4), The following formula (a3-4) (OP2.87, boiling point 465.2°C, molecular weight 338.4), The following formula (a3-5) (OP2.68, boiling point 465.7°C, molecular weight 364.4), The following formula (a3-6) (OP2.50, boiling point 433.1°C, molecular weight 320.3), The following formula (a3-7) (OP2.64, boiling point 468.1°C, molecular weight 326.4), The following formula (a3-8) (OP 3.25, boiling point 553.4°C, molecular weight 358.4), The following formula (a3-9) (OP2.63, boiling point 443.9°C, molecular weight 322.4), The following formula (a3-10) (OP2.89, boiling point 509.3°C, molecular weight 406.4), The following formula (a3-11) (OP2.63, boiling point 450.0°C, molecular weight 322.4), The following formula (a3-12) (OP 3.00, boiling point 476.5°C, molecular weight 366.4), The following formula (a3-13) (OP2.68, boiling point 447.4°C, molecular weight 364.4), The following formula (a3-14) (OP2.36, boiling point 543.8°C, molecular weight 398.5), The following formula (a3-15) (OP3.27, boiling point 526.9°C, molecular weight 396.4), The following formula (a3-16) (OP2.67, boiling point 417.2°C, molecular weight 268.3), The following formula (a3-17) (OP2.67, boiling point 417.2°C, molecular weight 268.3), The following formula (a3-18) (OP2.67, boiling point 417.2°C, molecular weight 268.3), The following formula (a3-19) (OP2.67, boiling point 417.2°C, molecular weight 268.3), The following formula (a3-20) (OP2.71, boiling point 438.8°C, molecular weight 296.3), The following formula (a3-21) (OP2.71, boiling point 438.8°C, molecular weight 296.3),

[0052] Other compounds (a3) ​​in this disclosure 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-benzenedi(meth)acrylate, o-, m- or p-xylylenedi(meth)acrylate.

[0053] Examples of commercially available polyfunctional (meth)acrylate compounds (a3) ​​as described 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), and 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)

[0054] In this disclosure, the content of the polyfunctional acrylate compound (a3) ​​in the polymerizable compound (a) is 0 parts by mass or more and 55 parts by mass or less per 100 parts by mass of the total amount of polymerizable compound (a). Preferably, it is 5 parts by mass or more and 50 parts by mass or less, more preferably 10 parts by mass or more and 45 parts by mass or less. When the content of compound (a3) ​​is greater than 55 parts by mass, it tends to become difficult to achieve low viscosity in the curable composition when the solvent is removed.

[0055] 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 an 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 a propylene oxide group.

[0056] The proportion of component (a) in the curable composition (A) is preferably 40% to 99% by weight, relative to the total mass of all components excluding solvent (d), i.e., the combination of component (a), component (b) described later, and component (c) described later. It is more preferably 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.

[0057] At least a portion of component (a) of this disclosure, which may be added in multiple forms, may be polymers having polymerizable functional groups. Such polymers preferably contain 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).

[0058] In formulas (1) to (6), each substituent R is a substituent that independently contains a substructure containing an aromatic ring, １is 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. In practice, the upper limit of the formula weight of substituent R is 500 or less.

[0059] 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 particular upper limit to 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 mentioned above, 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 mentioned above, solubility in the solvent 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 disclosure, unless otherwise specified, the weight-average molecular weight (Mw) refers to that measured by gel permeation chromatography (GPC).

[0060] 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.

[0061] 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. For example, it is preferable that the blending ratio be 0.1% by weight or more and 10% by weight or less, and more preferably 0.5% by weight or more and 5% by weight or less, relative to the total mass of all components excluding solvent (d). By blending the polymer having polymerizable functional groups at a ratio of 0.1% by weight or more, heat resistance, dry etching resistance, mechanical strength, and low volatility can be improved. Furthermore, by blending the polymer having polymerizable functional groups at a ratio of 60% by weight or less, the viscosity can be kept within the upper limit specifications described later.

[0062] In addition to the compounds (a1), (a2), and (a3) ​​described above, component (a) of this disclosure may also include styrene compounds, vinyl compounds, allyl compounds, fuma compounds, and maleyl compounds.

[0063] Specific examples of styrene compounds include, but are not limited to, the following: 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, and other alkylstyrenes; fluorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, o-bromostyrene, m-bromostyrene, p-bromostyrene, dibromostyrene and iodostyrene. Halogenated styrenes such as lene; compounds having a styryl group as a polymerizable functional group, including 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.

[0064] Specific examples of vinyl compounds include, but are not limited to, the following: 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 (compounds having a vinyl group as a polymerizable functional group, such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, divinyl adipate, (meth)acrylonitrile, etc.). In this specification, (meth)acrylonitrile is a general term for acrylonitrile and methacrylonitrile.

[0065] Examples of allyl compounds include, but are not limited to, allyl acetate, allyl benzoate, diallyl adipate, diallyl terephthalate, diallyl isophthalate, and diallyl phthalate.

[0066] Examples of fumarate 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, and dibenzyl fumarate.

[0067] 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, and dibenzyl maleate.

[0068] 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.).

[0069] In the film formation method of this disclosure, since it takes several milliseconds to several hundred seconds for droplets of the curable composition (A) discretely arranged on the substrate to bond together and form a substantially continuous liquid film, a waiting step described later is necessary. In the waiting step, the solvent (d) is allowed to volatilize, while the polymerizable compound (a) must not volatilize. Therefore, it is preferable that the boiling points of the polymerizable compound (a), which may contain multiple types, all be 250°C or higher under normal pressure, more preferably 300°C or higher, and even more preferably 350°C or higher. Furthermore, in order to obtain high dry etching resistance and high heat resistance in the cured film of the curable composition (A), it is preferable to include at least compounds having a ring structure such as an aromatic structure, an aromatic heterocyclic structure, or an alicyclic structure.

[0070] <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.

[0071] 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, and 2-(o- or p-methoxyphenyl)-4,5-diphenylimidazole dimer; benzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone (Michler ketone), N,N'-tetraethyl Benzophenone derivatives such as 4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, and 4,4'-diaminobenzophenone; α-aminoaromatic 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, and 2-t- Quinones such as thylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1-chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenantaraquinone, 2-methyl-1,4-naphthoquinone, 2,3-dimethylanthraquinone; benzoin ether derivatives such as benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether; benzo Benzoin derivatives such as benzoin, methylbenzoin, ethylbenzoin, and propylbenzoin; benzyl derivatives such as benzyldimethylketal; 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 benzylketal, 1-hydroxycyclohexylphenylketone, and 2,2-dimethoxy-2-phenylacetophenone;Thioxanthone derivatives such as thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, and 2-chlorothioxanthone; acylphosphine 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; 1,2-octanedione, 1-[4-(phenyl Oxime ester derivatives such as thio)-,2-(O-benzoyl oxime), etanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyl oxime); xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one.

[0072] 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), and Yubecryl P36 (manufactured by UCB).

[0073] Of the radical generators described above, component (b) is preferably an acylphosphine oxide polymerization initiator. Among the radical generators described above, the acylphosphine oxide polymerization initiators are as follows: Acylphosphine 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.

[0074] 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 blending component (b) at 0.1% by weight or more, the curing rate of the composition can be increased and the reaction efficiency can be improved. Furthermore, by blending component (b) at 50% by weight or less, a cured film with a certain degree of mechanical strength can be obtained.

[0075] <Component (c): Non-polymerizable compound> In addition to components (a) and (b) described above, the curable composition (A) in this disclosure may further contain a non-polymerizable compound as component (c) to the extent that it does not impair the effects of this disclosure, 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, internal release agents, antioxidants, polymer components, and other additives. Component (c) may contain multiple types of the compounds described above.

[0076] 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.

[0077] 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).

[0078] Here, interaction refers to energy transfer or electron transfer from the excited sensitizing dye to component (b), the photopolymerization initiator. Specific examples of sensitizing dyes include, but are not limited to, the following: 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, and pyrylium salt dyes.

[0079] 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.

[0080] Specific examples of such hydrogen donors include, but are not limited to, 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. A single hydrogen donor may be used alone, or two or more may be used in combination. Furthermore, the hydrogen donor may also function as a sensitizer.

[0081] 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 disclosure, as described later, there are restrictions on the amount of fluorine-based surfactants that can be added. The internally added release agent in this disclosure 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.

[0082] Fluorine-based surfactants include the following: polyalkylene oxide (polyethylene oxide, polypropylene oxide, etc.) adducts of alcohols having a perfluoroalkyl group, and polyalkylene oxide (polyethylene oxide, polypropylene oxide, etc.) adducts of perfluoropolyethers.

[0083] 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.

[0084] 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).

[0085] Furthermore, the internally added mold 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 having 2 to 4 carbon atoms to an alkyl alcohol having 1 to 50 carbon atoms.

[0086] Examples of alkyl alcohol polyalkylene oxide adducts include: 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, and stearyl alcohol ethylene oxide / propylene oxide adduct.

[0087] 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.

[0088] Examples of polyalkylene oxides include: 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, and monosuccinate esters.

[0089] 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), polyoxyethylene decyl ether (decyl alcohol ethylene oxide adduct) (FINESURF D-1303, D-1305, D-1307, D-1310), polyoxyethylene lauryl ether (lauryl alcohol ethylene oxide adduct) (BLAUNON EL-1505), polyoxyethylene cetyl ether (cetyl alcohol ethylene oxide adduct) (BLAUNON CH-305, CH-310), polyoxyethylene stearyl ether (stearyl alcohol ethylene oxide adduct) (BLAUNON) manufactured by Aoki Oil & Fat Industry Co., Ltd. SR-705, SR-707, SR-715, SR-720, SR-730, SR-750), random polymerization type polyoxyethylene polyoxypropylene stearyl ether from Aoki Oil & Fat Industry (BLAUNON SA-50 / 50 1000R, SA-30 / 70 2000R), polyoxyethylene methyl ether from BASF (Pluriol® A760E), and polyoxyethylene alkyl ether from Kao (Emulgen series).

[0090] Furthermore, commercially available polyalkylene oxides may be used, such as BASF's ethylene oxide-propylene oxide copolymer (Pluronic PE6400).

[0091] 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 of the total mass of component (a), component (b), and component (c), i.e., the total mass of all components excluding the 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 of the total mass of all components excluding the 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.

[0092] <Component (d): Solvent> The curable composition in this disclosure may contain one or more solvents as component (d). Each of the one or more solvents may have a boiling point of 80°C or higher and less than 250°C at normal pressure. Examples of component (d) include solvents in which components (a), (b), and (c) dissolve, such as alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and nitrogen-containing solvents. Component (d) may be used alone or in combination of two or more. The boiling point of component (d) at normal pressure is 80°C or higher, preferably 140°C or higher, and particularly preferably 150°C or higher. Furthermore, the boiling point of component (d) at normal pressure is less than 250°C, and particularly preferably less than 200°C. Therefore, the boiling point of component (d) at normal pressure is preferably 80°C or higher and less than 250°C, for example, preferably 150°C or higher and less than 200°C. If the boiling point of component (d) at atmospheric pressure is less than 80°C, the evaporation rate in the waiting step described later will be too fast, and component (d) may evaporate before the droplets of curable composition (A) can bond together, potentially preventing the droplets of curable composition (A) from bonding. Furthermore, if the boiling point of component (d) at atmospheric pressure is 250°C or higher, the evaporation of solvent (d) will be insufficient in the waiting step described later, potentially leaving component (d) in the cured product of curable composition (A).

[0093] Examples of alcohol-based solvents include: 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 alcohol Monoalcohol solvents such as ethanol, 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.

[0094] Examples of ketone solvents include: 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, and phenthone.

[0095] Examples of ether-based solvents include: 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 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.

[0096] Examples of ester solvents include: 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 ethyl acetate, diethylene glycol mono-n-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol 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.

[0097] Examples of nitrogen-containing solvents include the following: N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionamide, and N-methylpyrrolidone.

[0098] 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.

[0099] Furthermore, the following are even more preferred: propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol acetate monomethyl ether, propylene glycol acetate monoethyl ether, and propylene glycol acetate monopropyl ether.

[0100] Furthermore, propylene glycol monomethyl ether acetate is particularly preferred. Ethyl isocyanurate di(meth)acrylate is also a good example.

[0101] In this disclosure, preferred solvents are solvents 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.

[0102] Furthermore, in this disclosure, a polymerizable compound having a boiling point of 80°C or higher and less than 250°C at atmospheric pressure may also be used as component (d). Examples of polymerizable compounds having a boiling point of 80°C or higher and less than 250°C at atmospheric pressure include the following: cyclohexyl acrylate (198°C), benzyl acrylate (229°C), isobornyl acrylate (245°C), tetrahydrofurfuryl acrylate (202°C), trimethylcyclohexyl acrylate (232°C), isooctyl acrylate (217°C), n-octyl acrylate (228°C), ethoxyethoxyethyl acrylate (boiling point 230°C), divinylbenzene (193°C), 1,3-diisopropenylbenzene (218°C), styrene (145°C), and α-methylstyrene (165°C).

[0103] In this disclosure, when the total volume of the curable composition (A) is 100%, the content of solvent (d) is greater than 5% by volume and 95% or less by volume, preferably 10% to 90% by volume, and more preferably 20% to 80% by volume. If the content of solvent (d) is less than 5% by volume, a thin film cannot be obtained after the evaporation of solvent (d) under conditions in which a substantially continuous liquid film can be obtained. Also, if the content of solvent (d) is greater than 95% by volume, a thick film cannot be obtained after the evaporation of solvent (d) even if droplets are dropped as densely as possible by the inkjet method.

[0104] <Temperature during compounding of curable composition> When preparing the curable composition (A) in this disclosure, 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).

[0105] <Viscosity of the Curable Composition> The curable composition (A) in this disclosure is a liquid. This is because, in the placement step described later, droplets of the curable composition (A) are discretely dropped onto the substrate by an inkjet method. The viscosity of the curable composition (A) in this disclosure is 2 mPa·s or more and 60 mPa·s or less at 23°C, preferably 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 ejection of droplets 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 about 1.0 to 3.0 pL, which is preferred in this disclosure.

[0106] The viscosity at 23°C of the mixture of components of the curable composition (A) excluding solvent (d), i.e., the viscosity at 23°C of the mixture of components excluding solvent (d) of the curable composition (A), is preferably 10 mPa·s or more and 100 mPa·s or less. Preferably, the viscosity at 23°C of the mixture of components excluding solvent (d) of the curable composition (A) is preferably 15 mPa·s or more and 90 mPa·s or less, more preferably 20 mPa·s or more and 80 mPa·s or less. Even more preferably, it is preferably 25 mPa·s or more and 70 mPa·s or less. By making the viscosity of the components of the curable composition (A) excluding solvent (d) 100 mPa·s or less, the spread and fill are completed quickly when the curable composition (A) is brought into contact with the mold. Therefore, by using the curable composition (A) in this disclosure, 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) 10 mPa·s or higher, it is possible to prevent unwanted flow of droplets of the curable composition (A) after the solvent (d) has evaporated. 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.

[0107] <Surface Tension of Curable Composition> Regarding the surface tension of the curable composition (A) in this disclosure, it is preferable that the surface tension at 23°C of 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 of 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. Note that the higher the surface tension, for example, if it is 5 mN / m or more, the stronger the capillary force will be, so when the curable composition (A) is brought into contact with the mold, filling (spreading and filling) will 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 will be a cured film with a smooth surface.

[0108] <Contact Angle of Curable Composition> Regarding the contact angle of the curable composition (A) in this disclosure, 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 will 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.

[0109] <Impurities in the curable composition> The curable composition (A) in this disclosure preferably contains as few impurities as possible. Impurities refer to substances other than the components (a), (b), (c), and (d) described above. Therefore, the curable composition (A) in this disclosure is preferably obtained through a purification process. Such a purification process may include filtration using a filter.

[0110] For filtration using a filter, it is preferable to mix components (a), (b), and (c) described above and then filter the mixture 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 through 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 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.

[0111] <Glass transition temperature after curing of curable composition> If the glass transition temperature is sufficiently higher than the temperature at the time of demolding, the cured product at the time of demolding will be in a strong glassy state, i.e., will exhibit high mechanical strength. Therefore, the pattern is less likely to collapse or break due to the impact of demolding. Accordingly, when the demolding process is carried out at room temperature, the glass transition temperature of the cured product is preferably 80°C or higher, more preferably 100°C or higher, and particularly preferably 150°C or higher.

[0112] Methods for measuring the glass transition temperature of photocured materials include differential scanning calorimetry (DSC) and dynamic viscoelasticity measurement. For example, measurements using DSC are performed as follows: (1) The intersection point is determined between a straight line extending the low-temperature baseline of the DSC curve of the photocured material (the portion of the DSC curve in the temperature range where no transition or reaction occurs in the test specimen) toward the high-temperature side, and a tangent line drawn at the point where the slope of the curve representing the stepwise change portion of the glass transition is maximum. (2) From the determined intersection point, the extrapolation glass transition onset temperature (Tig) is determined as the glass transition temperature. Examples of main instruments include the STA-6000 (manufactured by Perkin Eimer).

[0113] On the other hand, when measurements are performed using a dynamic viscoelasticity instrument, the temperature at which the loss tangent (tanδ) of the photocured material is maximized is defined as the glass transition temperature. Examples of instruments capable of measuring dynamic viscoelasticity include the MCR301 (manufactured by Anton Paar).

[0114] Furthermore, when using the curable composition in this disclosure 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 metallic impurities in the curable composition is preferably 10 ppm or less, and more preferably 100 ppb or less.

[0115] In this specification, a substrate is described as a component on which droplets of the curable composition (A) are discretely dropped.

[0116] The substrate is the substrate to be processed, and typically a silicon wafer is used. The substrate may have a layer to be processed on its surface. The substrate may also have other layers formed beneath the layer to be processed. Furthermore, if a quartz substrate is used as the substrate, a replica of the mold for imprinting (replica mold) can be manufactured. However, the substrate is not limited to silicon wafers or quartz substrates. The substrate can be arbitrarily selected from those known as semiconductor device substrates, such as aluminum, titanium-tungsten alloy, aluminum-silicon alloy, aluminum-copper-silicon alloy, silicon oxide, and silicon nitride. It is preferable to improve the adhesion of the substrate or the layer to be processed 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.

[0117] The pattern formation method in this disclosure will be described with reference to Figures 1[1] to 1[7]. In this disclosure, the formed cured film 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. Generally, a film formation method that uses light to form a film having a nano-sized (1 nm to 100 nm) pattern (uneven structure) is called an optical imprint method. The film formation method in this disclosure uses an optical imprint method to form a film of a curable composition in the space between a mold and a substrate. However, the curable composition may be cured by other energy (e.g., heat, electromagnetic waves). Furthermore, the film formation method in this embodiment may be implemented as a method for forming a film having a pattern, i.e., as a pattern formation method, or as a method for forming a film without a pattern (e.g., a planarized film), i.e., as a planarized film formation method.

[0118] The following describes an example in which the film formation method in this embodiment is applied to a pattern formation method. The pattern formation method includes, for example, a formation step, a placement step, a waiting step, a contact step, a curing step, and a demolding step. The formation step is a step of forming a base layer. The placement step is a step of discretely placing droplets of the curable composition (A) on the base layer. The waiting step is a step of waiting for the droplets of the curable composition (A) to bond together and for the solvent (d) to volatilize. 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 demolding step is a step of separating the mold from the cured film of the curable composition (A). The placement step is performed after the formation step, 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 demolding step is performed after the curing step.

[0119] <Placement Process> In the placement process, droplets of the curable composition (A) are discretely placed on the substrate, as schematically shown in Figure 1 [1]. A substrate with a laminated underlayer may be used as the substrate. Furthermore, the surface of the substrate may have improved adhesion to the curable composition (A) through surface treatment such as silane coupling treatment, silazane treatment, or deposition of an organic thin film.

[0120] As a method for arranging droplets of the curable composition (A) on the substrate, the inkjet method is particularly preferred. It is preferable that the droplets of the curable composition (A) be densely arranged on the substrate region opposite to the region where the recesses constituting the mold pattern are densely present, and sparsely arranged on the substrate region opposite to the region where the recesses constituting the mold pattern are sparsely present. As a result, the film (residual film) of the curable composition (A) formed on the substrate, as described later, is controlled to have a uniform thickness regardless of the density of the mold pattern.

[0121] The thicker the residual film thickness, the lower the possibility of damage to the mold pattern due to foreign matter present between the mold and the substrate. Figure 4 schematically shows the effect of foreign matter P sandwiched between the mold M and the substrate S on the uneven pattern of the mold M. In Figure 4, in the placement step, a liquid film LC of the curable composition (A) is placed on the workpiece layer PL formed on the outermost layer of the substrate S. Then, in the contact step, the mold M is brought into contact with the liquid film LC of the curable composition (A) from which the solvent (d) has been removed. At this time, in the conventional technique, the uneven pattern of the mold M may be damaged by sandwiching foreign matter P that is thicker than the thickness of the residual film R. On the other hand, in this embodiment, the residual film R is made thicker than in the conventional technique. In Figure 4, the residual film R is shown as a film filled between the most protruding part of the mold M and the substrate S. Therefore, the residual film thickness corresponds to the distance between the most protruding part of the mold M and the substrate S (or the workpiece layer PL on it). In one example, the thickness of the residual film R sandwiched between the most protruding part of the mold M and the substrate S is 50 nm or more. As a result, even if large foreign objects are present, these foreign objects are embedded within the residual film, preventing damage to the uneven pattern. In this disclosure, because the residual film is thick, there is a high tolerance for differences in the height of the unevenness on the substrate surface. In one example, the height difference of the mold's unevenness is less than or equal to the thickness of the residual film. However, it should be noted that if the residual film is too thick, it may become difficult to expose the substrate surface in the residual film etching process described later.

[0122] To define the volume of curable composition (A) to be placed, an index called the average residual liquid film thickness is defined. The average residual liquid film thickness is the value obtained by dividing the volume of curable composition (A) (excluding solvent (d)) placed in the placement process by the area of ​​the film-forming region of the mold. The volume of curable composition (A) (excluding solvent (d)) is the sum of the volumes of individual droplets of curable composition (A) after the solvent (d) has evaporated. According to this definition, the average residual liquid film thickness can be defined regardless of the surface irregularities of the substrate, even if the substrate surface is uneven.

[0123] <Waiting Step> In this disclosure, a waiting step is provided between the placement step and the contact step. Here, the average initial liquid film thickness is defined as the value obtained by dividing the total volume of droplets of curable composition (A) dropped in one pattern formation by the total area of ​​the region where a pattern is formed in one pattern formation (pattern formation region). In the waiting step, the droplets of curable composition (A) spread out on the substrate as schematically shown in Figure 1[2]. As a result, the entire pattern formation region of the substrate is covered with curable composition (A). When the average initial liquid film thickness is 80 nm or more, as schematically shown in Figure 1[3], the droplets of curable composition (A) combine on the substrate to form a substantially continuous liquid film, as demonstrated by numerical calculations in the examples described later. Furthermore, when the average initial liquid film thickness is 89 nm or more, the surface of the liquid film becomes flat, as demonstrated by numerical calculations in the examples described later. A liquid film with an average initial film thickness of 80 nm or more is formed by applying 80 droplets / mm of a curable composition (A) in a volume of 1.0 pL or more. ２ This can be obtained by arranging them at the above density. Similarly, a liquid film with an average initial liquid film thickness of 89 nm can be obtained by arranging droplets of the curable composition (A) in a volume of 1.0 pL or more at a density of 89 droplets / mm². ２ This can be obtained by arranging them at a certain density.

[0124] Referring to Figures 2[1] to 2[4], the flow behavior of droplets of the curable composition (A) placed on the substrate during the waiting process will be explained. As shown in Figure 2[1], droplets of the curable composition (A) are discretely placed on the substrate, and as shown in Figure 2[2], each droplet gradually spreads on the substrate. Then, as shown in Figure 2[3], the droplets of the curable composition (A) on the substrate begin to combine to form a liquid film, and as shown in Figure 2[4], a continuous liquid film is formed (the surface of the substrate is covered with the curable composition (A), and there are no exposed surfaces). The state of the curable composition (A) as shown in Figure 2[4] is referred to as a "substantially continuous liquid film".

[0125] Furthermore, during the waiting process, the solvent (d) contained in the liquid film is evaporated, as schematically shown in Figure 1 [4]. The amount of solvent (d) remaining in the liquid film after the waiting process is preferably 10% by volume or less, assuming the total weight of components other than solvent (d) is 100% by volume. If the amount of solvent (d) remaining is greater than 10% by volume, the mechanical properties of the cured film may be reduced.

[0126] 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 heating is carried out, for example, at a temperature of 30°C to 200°C, preferably 80°C to 150°C, and particularly preferably 90°C to 110°C. The heating time can be 10 seconds to 600 seconds. The baking process can be carried out using a known heating device such as a hot plate or an oven.

[0127] The waiting period is, for example, 0.1 seconds to 600 seconds, preferably 10 seconds to 300 seconds. If the waiting period is shorter than 0.1 seconds, the bonding between droplets of the curable composition (A) will be insufficient, and a substantially continuous liquid film will not be formed. If the waiting period exceeds 600 seconds, productivity will decrease. Therefore, in order to suppress the decrease in productivity, substrates that have completed the placement process may be sequentially moved to the waiting process, and the waiting process may be carried out in parallel for multiple substrates, with substrates that have completed the waiting process being sequentially moved to the contact process. In the prior art, theoretically, it takes several thousand to tens of thousands of seconds for a substantially continuous liquid film to be formed, but in reality, the spreading of droplets of the curable composition is delayed due to the effect of volatilization, making it impossible to form a continuous liquid film.

[0128] During the waiting process, when solvent (d) evaporates, a substantially continuous liquid film consisting of components (a), (b), and (c) remains. The average remaining liquid film thickness of the substantially continuous liquid film after solvent (d) has evaporated (removed) is thinner than the liquid film by the amount of solvent (d) that has evaporated. In one example, the average remaining liquid film thickness after the waiting process may be 20 nm or less. The pattern formation region of the substrate remains covered over its entire surface by a substantially continuous liquid film of the curable composition (A) from which solvent (d) has been removed.

[0129] <Contact Process> In the contact process, as schematically shown in Figure 1[5], a substantially continuous liquid film of the curable composition (A), from which the solvent (d) has been removed, is brought into contact with the mold. The contact process 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, and this liquid becomes a liquid film that fills the fine patterns of the mold.

[0130] Figure 3 shows a comparison (difference) between the contact process in the prior art and the contact process in this disclosure. In this embodiment, during the waiting process, the droplets D of the curable composition (A) become a substantially continuous liquid film LF from which the solvent (d) has been removed, so the volume of gas G trapped between the mold M and the substrate S is reduced. Therefore, the spreading of the curable composition (A) in the contact process is completed quickly.

[0131] If the spreading and filling of the curable composition (A) is completed quickly during the contact process, the time the mold is kept in contact with the curable composition (A) (the time required for the contact process) can be shortened. Shortening the time required for the contact process leads to a reduction in the time required for pattern formation (film formation), thus improving productivity. 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 spreading and filling will be insufficient, and defects called unfilled defects tend to occur frequently.

[0132] As for the mold, if the curing process includes a light irradiation process, a mold made of a light-transmitting material is used, 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 material for the mold, a resin that does not dissolve in the components contained in the curable composition is selected. Quartz is suitable as a material for the mold because it has a small coefficient of thermal expansion and low pattern distortion.

[0133] 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 pattern on the mold, the less force is required to separate the mold from the cured film of the curable composition during the release 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 with each other, resulting in adhesion or damage. However, it is advantageous to have a pattern element height of about 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 substrate will be reduced.

[0134] The mold may be surface-treated before the contact process to improve the release properties of the mold 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. For example, commercially available coating-type release agents such as Optool® DSX manufactured by Daikin Industries, Ltd. 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.

[0135] 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. Preferably, the pressure applied to the curable composition (A) when the mold is brought into contact with the curable composition (A) is 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.

[0136] 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.

[0137] <Curing Process> In the curing process, as schematically shown in Figure 1[6], the curable composition (A) is cured by irradiating it with light as curing energy to form a cured film. In the curing process, for example, the curable composition (A) is irradiated with light through a mold. More specifically, the curable composition (A) filled in the fine pattern of the mold is irradiated with light through the mold. As a result, the curable composition (A) filled in the fine pattern of the mold hardens to form a cured film having a pattern.

[0138] 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 irradiation light be ultraviolet light. This is because many commercially available curing aids (photopolymerization initiators) are compounds that are 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 F ２ Lasers are one example of such light sources. However, ultra-high pressure mercury lamps are particularly preferred as light sources that emit ultraviolet light. There may be one or more light sources. Light may be irradiated over the entire surface of the curable composition (A) filled in the fine pattern of the mold, or only over a portion of the surface (limited area). Light may also be irradiated over the entire surface of the substrate intermittently multiple times, or continuously over the entire surface of the substrate.

[0139] Furthermore, light may be irradiated onto a first region of the substrate during the second irradiation process, and light may also be irradiated onto a second region of the substrate that is different from the first region during the second irradiation process.

[0140] <Release Process> In the release process, the mold is separated from the cured film, as schematically shown in Figure 1[7]. By separating the patterned cured film from the mold, a cured film with a pattern that is an inverted version of the mold's fine pattern is obtained in an upright state. Here, some of the cured film remains even in the recesses of the patterned cured film. This is the film that remains between the most convex part of the mold and the substrate, and is called the residual film.

[0141] 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.

[0142] <Repeat> By a series of steps (manufacturing process) having the above-described arrangement step followed by a demolding step in this order, a cured film having the desired uneven pattern shape (a pattern shape that follows the uneven shape of the mold) at the desired position can be obtained.

[0143] In the pattern formation method of this embodiment, the repeating units (shots) from the placement step to the demolding step can be repeated multiple times on the same substrate, making it possible to obtain a cured film having multiple desired patterns at desired positions on the substrate.

[0144] Planarization Film Formation Method The following describes an example in which the film formation method of this disclosure is applied to a planarization film formation method. The planarization film formation method includes, for example, a placement step, a waiting step, a contact step, a curing step, and a demolding step. The placement step is a step of placing droplets of the curable composition (A) on a substrate. The waiting step is a step of waiting for the droplets of the curable composition (A) to bond with each other and for the solvent (d) to volatilize. The contact step is a step of bringing the curable composition (A) into contact with a mold (also called a superstraight). The curing step is a step of curing the curable composition (A). The demolding step is a step of separating the mold from the cured film of the curable composition (A). In the planarization film formation method, a substrate having irregularities with a height difference of about 10 to 1,000 nm is used as the substrate, and a mold having a flat surface is used as the mold, and a cured film having a surface that conforms to the flat surface of the mold is formed through the contact step, curing step and demolding step. In the placement process, droplets of the curable composition (A) are densely arranged in the recesses of the substrate, and the curable composition (A) is sparsely arranged in the protrusions of the substrate. The waiting process is performed after the placement process, the contact process is performed after the waiting process, the curing process is performed after the contact process, and the demolding process is performed after the curing process.

[0145] A cured film having a pattern formed by the pattern forming method disclosed herein can be used as is as a component of at least a part of various articles. Furthermore, a cured film having a pattern formed by the pattern forming method disclosed herein can be temporarily used as a mask for etching, ion implantation, etc., on a substrate (or the layer to be processed if the substrate has a layer to be processed). After etching, ion implantation, etc., is performed in the substrate processing process, the mask is removed. This allows for the manufacture of various articles.

[0146] When removing hardened material from recesses in a hardened material pattern by etching, the specific method is not particularly limited, and conventionally known methods, such as dry etching, can be used. Conventionally known dry etching apparatus can be used for dry etching. The source gas used during dry etching is appropriately selected depending on the elemental composition of the hardened material being etched, but for example, the following gases can be used: CF ４ , C ２ F ６ , C ３ F ８ , CCl ２ F ２ , CCl ４ , CBrF ３ , BCl ３ , PCL ３ SF ６ , Cl ２ Halogen gases such as O ２ CO, CO ２ Gases containing oxygen atoms such as He, N ２ , inert gases such as Ar, H ２ NH ３ These gases can also be used in mixtures. In this case, the photocurable film requires high dry etching resistance in order to process the substrate with good yield.

[0147] Articles include electrical circuit elements, optical elements, MEMS, recording elements, sensors, or molds. 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 FPGA. Optical elements include microlenses, light guides, waveguides, anti-reflective coatings, diffraction gratings, polarizing elements, color filters, light-emitting elements, displays, and solar cells. MEMS include DMDs, microfluidics, and electromechanical conversion elements. Recording elements include optical discs such as CDs and DVDs, magnetic discs, magneto-optical discs, and magnetic heads. Sensors include magnetic sensors, optical sensors, and gyro sensors. Molds include molds for imprinting.

[0148] Furthermore, known photolithography processes such as imprint lithography and extreme ultraviolet (EUV) exposure can be performed on the planarized film formed by the planarized film formation method of this disclosure. Alternatively, a spin-on-glass (SOG) film and / or silicon oxide layer can be laminated, and a curable composition can be applied thereon for photolithography. This makes it possible to manufacture devices such as semiconductor devices. It is also possible to form devices including such devices, such as electronic devices such as displays, cameras, and medical devices. Examples of devices include LSIs, system LSIs, DRAMs, SDRAMs, RDRAMs, D-RDRAMs, and NAND flash memory.

[0149] Inversion Process The curable composition (A) of this disclosure can also be used as an inversion layer material for an inversion process. An inversion process is a process that includes, for example, the following steps after the placement step, contact step, curing step, and demolding step described above: - An inversion layer formation step (formation step) in which the inversion layer material is placed on the irregularities formed on the cured film to form an inversion layer. - An excess inversion layer removal step (removal step) in which the upper part of the inversion layer is removed so that the top surface of the convex parts of the irregularities is exposed, with the inversion layer embedded in the recesses of the irregularities formed on the cured film. - A residual film etching step in which the cured film is etched to the surface of the substrate using the inversion layer embedded in the recesses as a mask to form an inversion pattern. In this embodiment, as described above, the thickness of the residual film sandwiched between the most convex part 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 inversion process will be described in detail below.

[0150] <Inversion Layer Formation Process> As shown in Figure 5, a curable composition (A) is placed on the cured film CC having a pattern shape formed through the placement process and the release process, so as to fill the recesses of the pattern, thereby forming an inversion layer H.

[0151] <Excess Inversion Layer Removal Process> In the inversion layer formation process described above, an inversion layer is also formed on the upper part of the protrusions of the hardened film CC. Hereinafter, the inversion layer formed on the upper part of the protrusions of the hardened film CC in this manner will be referred to as the "excess inversion layer E". This excess inversion layer E needs to be removed until the upper part of the protrusions of the hardened film CC, which has a pattern shape, is exposed, as shown in Figure 5. Therefore, in the excess inversion layer removal process, the excess inversion layer E is removed in such a way that the top surface of the protrusions of the unevenness formed on the hardened film CC is exposed, while the inversion layer H is embedded in the recesses of the unevenness formed on the hardened film CC.

[0152] 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, but for example, fluorocarbon gases such as those shown below can be used. CF４ CHF ４ , C ２ F ６ , C ３ F ８ , C ４ F ８ , C ５ F ８ , C ４ F ６ , CCl ２ F ２ , CBrF ３ Etc. Alternatively, halogen-based gases such as those listed below can be used as the source gas during dry etching. CCl ４ , BCl ３ , PCL ３ SF ６ , Cl ２ These gases can also be used in mixtures.

[0153] <Residual Film Etching Process> The inversion layer H remaining 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 in the excess inversion layer removal process. Etching is continued until the surface of the workpiece layer PL of the substrate is exposed. If an intermediate transfer layer (C) that does not contain inorganic elements such as Si atoms, such as spin-on carbon (SOC), is formed between the surface of the workpiece layer PL of the substrate and the cured film CC, the intermediate transfer layer (C) is also etched.

[0154] This process creates a pattern with reversed irregularities compared to the hardened film CC (hereinafter referred to as the reversed pattern), as shown in Figure 5. While there are no particular limitations on the specific etching method, conventionally known methods, such as dry etching, can be used. A 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 O ２ CO, CO ２ Gases containing oxygen atoms such as He, N ２ , inert gases such as Ar, N ２ , H ２ NH ３These gases can be used. These gases can also be used in mixtures.

[0155] <Processing Process for the Workpiece Layer> Furthermore, in this embodiment, as shown in Figure 5, the workpiece layer PL on the substrate can be etched using the inverted pattern as a processing mask to obtain a workpiece layer having a pattern shape. Alternatively, the workpiece layer PL may be ion-implanted using the inverted pattern as a processing mask. The etching of the workpiece layer PL may be carried out under the same conditions as the etching of the excess inverted layer E described above, or under different conditions suitable for etching the workpiece layer PL. After processing the workpiece layer PL, the inverted pattern, which is the processing mask, may be removed.

[0156] Examples: To supplement the embodiments described above, more specific examples will be described.

[0157] According to Table 1 below, a curable composition (A) was prepared by mixing an N-vinyl compound (a1), a monofunctional acrylate compound (a2), a polyfunctional (meth)acrylate compound (a3), a photopolymerization initiator (b), and a solvent (d). The viscosity of curable composition (A) and curable composition (A) at 23°C after solvent (d) removal was measured. Furthermore, the OP of polymerizable compound (a) (i.e., the sum of compounds (a1), (a2), and (a3)) after solvent (d) removal was calculated using the method described above. In addition, the curing time of curable composition (A) after solvent removal and the glass transition temperature after curing were measured using the method described below. The measurement results are shown in Table 2.

[0158] The abbreviations used in Table 1 are as follows: • Monofunctional acrylate compound (a2): mPhOBzA: Same structure as described in the specific example of compound (a2). • Polyfunctional (meth)acrylate compound (a3): BPh44DA: Same structure as described in the specific example of polymerizable compound (a3). • Photopolymerization initiator (b): Omnirad819: Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (manufactured by IGM Resin). • Solvent (d): PGMEA: Propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical).

[0159] <Measurement of curing time of curable composition (A) during solvent removal and glass transition temperature after curing> Measurements were performed using a dynamic viscoelastic device MCR302 (manufactured by Anton Paar) equipped with a UV curing system and a heating unit. An 8 mm φ probe was used, with an exposure wavelength of 365 nm and an illuminance of 1.0 mW / cm². ２ The curing time and glass transition temperature were measured by exposing the curable composition (A) to a thickness of 100 μm to light for 900 seconds and then raising the temperature to 200°C. In this measurement, Omnirad 907 (manufactured by IGM Resin; 2-methyl-4'-(methylthio)-2-morpholinopropiophenone) was used as the photopolymerization initiator (b). This material has a smaller absorption coefficient at an exposure wavelength of 365 nm compared to Omnirad 819. It also has a storage modulus of 10. ７ The time to reach Pa was defined as the curing time, and the temperature at which the loss tangent (tanδ) of the photocured material is maximum was defined as the glass transition temperature.

[0160] <Inkjet ejection evaluation> The inkjet ejection evaluation was performed using a commercially available industrial material printer DMP-2850 (manufactured by Fujifilm). Examples 1 to 9 and Comparative Examples 1 to 3 obtained in Table 1 were each filled into a 1 pL cartridge, and the ejection process was observed using the built-in ejection observation camera and evaluated according to the following criteria. (Evaluation criteria) AAA: No distortion was observed at a flight speed of 11 m / sec or higher. AA: Very slight distortion was observed at a flight speed of 11 m / sec or higher, at a level that does not have practical effect. A: Very slight distortion was observed at a flight speed of 10 m / sec or higher, at a level that does not have practical effect. B: No ejection occurred.

[0161] <Evaluation of Filling Properties> Under conditions where the thickness of the liquid film after the solvent (d) evaporates is 100 nm, the curable compositions (A) of Examples 1 to 9 and Comparative Examples 1 to 3 were discretely dropped (placed) onto a silicon substrate, and the time until a substantially continuous liquid film was formed was measured and evaluated according to the following criteria. (Evaluation Criteria) AAA: A continuous liquid film was formed in less than 60 seconds. AA: A continuous liquid film was formed in 60 seconds or more but less than 100 seconds. A: A continuous liquid film was formed in 100 seconds or more but less than 200 seconds. B: A continuous liquid film was not formed even after 200 seconds.

[0162] <Evaluation of Pattern Collapse> The curable compositions (A) of Examples 1 to 9 and Comparative Examples 1 to 3 were subjected to a placement process, a waiting process, a contact process, a curing process, and a demolding process. The patterns obtained were observed and evaluated according to the following criteria. A quartz mold with a line-and-space (L / S) pattern of 50 nm depth and 20 nm width formed throughout the entire area was used. (Evaluation Criteria) AAA: Pattern collapse was observed in less than 0.1% of the pattern formation area. AA: Pattern collapse was observed in less than 1% of the pattern formation area. A: Pattern collapse was observed in less than 10% of the pattern formation area. B: Pattern collapse was observed in 10% or more of the pattern formation area.

[0163] <Evaluation of dry etching resistance> The hardened film obtained above was subjected to dry etching in a dry etching apparatus. ４ The film was exposed to plasma, and the weight change of the remaining film was measured and evaluated according to the following criteria: (Evaluation Criteria) AAA: The weight of the remaining cured film was 49% or more of the weight before etching. AA: The weight of the remaining cured film was 47% or more of the weight before etching. A: The weight of the remaining cured film was 43% or more of the weight before etching. B: The weight of the remaining cured film was less than 43% of the weight before etching.

[0164] The evaluation results are shown in Table 3. It can be seen that if the viscosity of the curable composition at 23°C is 2 mPa·s or more and 60 mPa·s or less, the inkjet ejection is good. It can be seen that if the viscosity at 23°C after solvent removal is 10 mPa·s or more and 100 mPa·s or less, the inkjet fillability is good, preferably 20 mPa·s or more and 80 mPa·s or less, and more preferably 25 mPa·s or more and 70 mPa·s or less.

[0165] Furthermore, if the glass transition temperature of the curable composition after curing was 80°C or higher, pattern collapse tended to be observed in areas of less than 10%. On the other hand, in Comparative Example 1, although the glass transition temperature was 80°C or higher, it is thought that the pattern collapse was observed in areas of 10% or more due to poor curing under conditions of insufficient exposure, resulting from the long curing time.

[0166] Furthermore, if the OP of polymerizable compound (a) was between 1.80 and 2.40, the weight of the remaining cured film was 49% or more of the weight before etching. Also, if the OP of polymerizable compound (a) was between 1.80 and 2.60, the weight of the remaining cured film was 47% or more of the weight before etching. If the weight of the remaining cured film was 47% or more of the weight before etching, and the OP of polymerizable compound (a) was between 1.80 and 2.70, the weight of the remaining cured film was 43% or more of the weight before etching.

[0167] The technical ideas derived from this disclosure are not limited to the exemplary embodiments disclosed, but are intended to encompass various modifications of the exemplary embodiments, or substitutions with equivalent structures or functions. The scope of the following claims should be interpreted in the broadest way to encompass all such modifications and equivalent structures and functions.

[0168] This application claims priority based on Japanese Patent Application No. 2025-009333 filed on 22 January 2025 and Japanese Patent Application No. 2025-243877 filed on 9 December 2025, and all of the contents of those applications are incorporated herein by reference.

Claims

1. A curable composition comprising a polymerizable compound (a), a photopolymerization initiator (b), and a solvent (d), wherein the content of the solvent (d) relative to the total curable composition is greater than 5% by volume and 95% by volume or less, the polymerizable compound (a) contains an N-vinyl compound (a1), a monofunctional acrylate compound (a2), and a polyfunctional (meth)acrylate compound (a3), the molecular weight of the N-vinyl compound (a1) is 150 or more and 300 or less, and the content of the N-vinyl compound (a1) is 5 parts by mass or more and less than 45 parts by mass per 100 parts by mass of the total amount of the polymerizable compound (a), characterized in that the curable composition is characterized in that 2. The curable composition according to claim 1, characterized in that the content of the polyfunctional (meth)acrylate compound (a3) ​​in the polymerizable compound (a) is 0 parts by mass or more and 55 parts by mass or less per 100 parts by mass of the total amount of the polymerizable compound (a).

3. The curable composition according to claim 1 or 2, characterized in that the polymerizable compound (a1) has two or more cyclic structures, and at least one of them contains an aromatic, aromatic heterocyclic, or alicyclic structure.

4. The curable composition according to any one of claims 1 to 3, characterized in that the N-vinyl compound (a1) comprises an N-vinylindole derivative represented by the following formula (1A). Formula (1A) (In the formula, R １ ~R ６ Each of these is independently a hydrogen atom, a C1-C10 alkyl group, an optionally substituted C6-C10 aryl group, an optionally substituted C2-C10 vinyl group, or an optionally substituted C2-C10 ethynyl group, and R １ ~R ６ At least two adjacent groups may be bonded to each other to form a ring.

5. The curable composition according to any one of claims 1 to 4, characterized in that the N-vinyl compound (a1) comprises an N-vinylcarbazole derivative represented by the following formula (2A). Formula (2A) (In the formula, R １ ~R ８ Each of these is independently a hydrogen atom, an optionally substituted C1-C10 alkyl group, an optionally substituted C6-C10 aryl group, an optionally substituted C2-C10 vinyl group, or an optionally substituted C2-C10 ethynyl group, and R １ ~R ８ At least two adjacent groups may be bonded to each other to form a ring.

6. The curable composition according to any one of claims 1 to 5, characterized in that the monofunctional acrylate compound (a2) has two or more cyclic structures, and at least one of them contains an aromatic, aromatic heterocyclic, or alicyclic structure.

7. The curable composition according to any one of claims 1 to 6, characterized in that the curable composition in the state from which the solvent (d) has been removed has a viscosity of 10 mPa·s or more and 100 mPa·s or less at 23°C.

8. The curable composition according to any one of claims 1 to 7, characterized in that the glass transition temperature of the cured product obtained by curing the curable composition in a state from which the solvent (d) has been removed is 80°C or higher.

9. The curable composition according to any one of claims 1 to 8, characterized in that the Onishi parameter (OP) of each polymerizable compound (a) is 1.80 or more and 2.70 or less.

10. The curable composition according to any one of claims 1 to 9, characterized in that the solvent (d) comprises one or more solvents, and the boiling point of each of the one or more solvents (d) at normal pressure is 80°C or higher and less than 250°C.

11. The curable composition according to claim 10, characterized in that the boiling point of each of the one or more solvents (d) under normal pressure is 150°C or higher and less than 200°C.

12. The curable composition according to any one of claims 1 to 11, characterized in that the curable composition is a curable composition for inkjet printing.

13. A film-forming method for forming a film of a curable composition in the space between a mold and a substrate, comprising: an arrangement step of discretely arranging a plurality of droplets of the curable composition according to any one of claims 1 to 12 on the substrate; a waiting step of waiting until each of the plurality of droplets discretely arranged on the substrate combines with adjacent droplets to form a continuous liquid film on the substrate, and the solvent contained in the liquid film is evaporated until the solvent content is 10% by volume or less of the total liquid film; and a contact step of bringing the mold and the liquid film on the substrate into contact after the waiting step.

14. The film forming method according to claim 13, characterized in that the waiting step includes a step of heating the substrate at a temperature of 30°C or higher and 200°C or lower, and for a period of 10 seconds or higher and 600 seconds or lower.

15. In the placement step, droplets of the curable composition having a volume of 1.0 pL or more are placed on the substrate at a density of 80 or more droplets / mm ２ The method for forming a film according to claim 13 or 14, characterized in that the droplets are placed at a density of 80 or more droplets / mm.

16. The film-forming method according to any one of claims 13 to 15, characterized in that the average remaining liquid film thickness, which is the value obtained by dividing the volume of the curable composition remaining after the waiting step by the area of ​​the film-forming region, is 20 nm or less.

17. The film forming method according to any one of claims 13 to 16, wherein the mold includes a pattern, the contact step involves bringing the pattern of the mold into contact with the liquid film on the substrate, and the film forming method further comprises a curing step after the contact step, in which the liquid film is cured to form a cured film having a pattern corresponding to the pattern of the mold.

18. The film forming method according to any one of claims 13 to 16, characterized in that the mold includes a flat surface, the contact step involves bringing the flat surface of the mold into contact with the liquid film on the substrate, and the film forming method further comprises a curing step after the contact step, in which the liquid film is cured to form a cured film having a surface that conforms to the flat surface of the mold.

19. A film forming method for forming a film of a curable composition in the space between a mold and a substrate, comprising: an arrangement step of discretely arranging a plurality of droplets of the curable composition according to any one of claims 1 to 12 on the substrate; a waiting step of waiting for each of the plurality of droplets discretely arranged on the substrate to combine with adjacent droplets to form a continuous liquid film on the substrate and for the solvent contained in the liquid film to evaporate; and a contact step of bringing the mold and the liquid film on the substrate into contact after the waiting step, wherein the waiting step includes a step of heating the substrate at a temperature of 30°C or more and 200°C or less and for 10 seconds or more and 600 seconds or less.

20. The film formation method according to claim 13, characterized in that the arrangement step involves discretely arranging the plurality of liquid droplets on the substrate using an inkjet method.

21. A pattern forming method comprising: an arrangement step of arranging a curable composition according to any one of claims 1 to 12 on a substrate; a contact step of bringing the curable composition into contact with a mold having irregularities after the arrangement step, wherein the thickness of the residual film sandwiched between the most convex part 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; a curing step of curing the liquid film of the curable composition after the contact step to form a cured film; a release step of separating the cured film from the mold after the curing step; a forming step of forming an inversion layer on the irregularities formed on the cured film after the release step; a removal step of removing the upper part of the inversion layer so that the top surface of the convex part of the irregularities is exposed, with the inversion layer embedded in the recess of the irregularities formed on the cured film; and an etching step of etching the cured film to the surface of the substrate using the inversion layer embedded in the recess as a mask to form an inversion pattern.

22. The pattern forming method according to 21, characterized in that, in the arrangement step, a plurality of droplets of the curable composition are discretely arranged on the substrate using an inkjet method.

23. A method for manufacturing an article, comprising: a step of forming a film of a curable composition on a substrate using a film forming method according to any one of claims 13 to 20; a step of processing the substrate on which the film has been formed in the first step; and a step of manufacturing an article from the processed substrate.

24. A method for manufacturing an article, comprising: a step of forming a pattern of a curable composition on a substrate using the pattern forming method described in claim 21 or 22; a step of processing the substrate on which the pattern has been formed in the first step; and a step of manufacturing an article from the processed substrate.

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