Negative resist composition and method for producing resist pattern

Abstract

To provide a negative resist composition capable of forming a resist pattern having good storage stability, and a method for producing a resist pattern using the negative resist composition.SOLUTION: There are provided a negative resist composition and a method for producing the same, the negative resist composition containing a resin (A1), an acid generator (B), and a crosslinking agent (E). The resin (A1) contains a structural unit represented by formula (a2-1) and a structural unit represented by formula (a2-4), and the acid generator (B) is a compound containing a specific acid generator. [In the formula (a2-1) and the formula (a2-4), Ra7 and Ra13 each independently represent a hydrogen atom or a methyl group.]SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a negative resist composition and a method for producing a resist pattern. [Background technology]

[0002] Patent Document 1 describes a negative resist composition containing a partially ethyl-etherified polyvinylphenol and an m-cresol novolac resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-42529 Summary of the Invention [Problem to be solved by the invention]

[0004] Negative resist compositions such as those described in Patent Document 1 often lack sufficient long-term (for example, one month) storage stability. Therefore, an object of the present invention is to provide a negative resist composition that is capable of forming a resist pattern with excellent storage stability, and a method for producing a resist pattern using such a negative resist composition. [Means for solving the problem]

[0005] As a result of intensive research into solving the above problems, the inventors have found that the above problems can be solved by a negative resist composition containing a resin (A1), an acid generator (B), and a crosslinking agent (E), wherein the resin (A1) has a predetermined structural unit, the acid generator (B) contains two or more types of acid generators having predetermined groups (chemical structures), and at least one of the acid generators is a compound represented by formula (b1). Further investigation led to the completion of the present invention.

[0006] That is, the present invention relates to the following negative resist composition and method for producing the same. [1] A negative resist composition comprising a resin (A1), an acid generator (B), and a crosslinking agent (E), The resin (A1) contains a structural unit represented by formula (a2-1) and a structural unit represented by formula (a2-4), The acid generator (B) contains at least two types of acid generators each having a group represented by formula (B1), and at least one of the acid generators is a compound represented by formula (b1). A negative resist composition. TIFF2025181636000001.tif48170 [In formula (a2-1) and formula (a2-4), R a7 , and R a13 each independently represents a hydrogen atom or a methyl group. R a10 , and R a14 are each independently an alkyl group having 1 to 6 carbon atoms. R a15 represents a hydrocarbon group having 1 to 12 carbon atoms. m 1 represents an integer between 0 and 4. 1 When is 2 or more, multiple R a10 may be the same or different from each other. m 2 represents an integer of 1 to 4. However, m 1 and m 2 The sum of these is 5 or less. m 3 represents an integer between 0 and 4. 3 When is 2 or more, multiple R a14 may be the same or different from each other. m 4 represents an integer of 1 to 4. 4 When is 2 or more, multiple R a15 may be the same or different from each other. However, m 3 and m 4 The sum of is 5 or less.] TIFF2025181636000002.tif23170[In formula (B1), R b1 represents a hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom, and a methylene group contained in the hydrocarbon group may be substituted with an oxygen atom or a carbonyl group.] TIFF2025181636000003.tif36170[In formula (b1), R b1 represents the same meaning as above. R b2 represents a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a thioalkyl group having 1 to 8 carbon atoms. Ring W b1 represents an aromatic hydrocarbon ring having 6 to 14 carbon atoms or an aromatic heterocyclic ring having 6 to 14 carbon atoms. x represents an integer of 0 to 6. When x is 2 or more, a plurality of R b2 may be the same or different.] [2] The acid generator (B) is (i) a combination of at least two compounds selected from compounds represented by formula (b1), or (ii) a combination of at least one compound selected from the compounds represented by formula (b1) and at least one compound selected from the compounds represented by formula (b2) and formula (b3); The negative resist composition according to [1], comprising: TIFF2025181636000004.tif50170[In formula (b2) to formula (b3), R b1 represents the same meaning as above. R b3 and R b4 each independently represents a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a thioalkyl group having 1 to 8 carbon atoms.] [3] The negative resist composition according to [1] or [2], wherein at least one compound selected from the compounds represented by formula (b1) contained in the acid generator (B) is a compound in which x is 1. [4] The negative resist composition according to any one of [1] to [3], further comprising a novolak resin. [5] The negative resist composition according to any one of [1] to [4], further comprising a quencher (C). [6] The negative resist composition according to any one of [1] to [5], wherein the crosslinking agent (E) is a melamine-based crosslinking agent or a glycoluril-based crosslinking agent. [7] A method for producing a resist pattern, comprising: (1) a step of applying the resist composition according to any one of [1] to [6] onto a substrate; (2) a step of drying the applied composition to form a composition layer; (3) exposing the composition layer to light; and (4) A step of heating and developing the composition layer after exposure A manufacturing method comprising: [Effects of the Invention]

[0007] According to the present invention, a negative resist composition having good storage stability can be obtained. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram schematically illustrating a pattern shape of a trench pattern of a resist pattern. DETAILED DESCRIPTION OF THE INVENTION

[0009] In this specification, unless otherwise specified, in the description of the structural formula of a compound, the term "hydrocarbon group" means a linear or branched chain hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a group formed by combining these groups. When the number of carbon atoms in the "hydrocarbon group" is specified, the group may be any of the above groups within the range permitted by the number of carbon atoms. When stereoisomers exist, all stereoisomers are included. In this specification, "(meth)acrylic acid" means "at least one of acrylic acid and methacrylic acid," and "(meth)acrylate" means "at least one of acrylate and methacrylate." In the groups described in this specification, those which can have both a straight-chain structure and a branched structure are interpreted as including both. In this specification, the term "solids content of a negative resist composition" refers to the sum of all components obtained by excluding the solvent (D), which will be described later, from the total amount of the negative resist composition.

[0010] 1. Negative resist composition The negative resist composition of the present invention contains a resin (hereinafter sometimes referred to as "resin (A1)") that includes a structural unit represented by formula (a2-1) (hereinafter sometimes referred to as structural unit (a2-1)) and a structural unit represented by formula (a2-4) (hereinafter sometimes referred to as structural unit (a2-4)), a crosslinking agent (hereinafter sometimes referred to as "crosslinking agent (E)"), and an acid generator (hereinafter sometimes referred to as "acid generator (B)"). Furthermore, the negative resist composition of the present invention may contain, as necessary, a novolak resin (hereinafter, sometimes referred to as "novolak resin (A2)"), a quencher (hereinafter, sometimes referred to as "quencher (C)"), a solvent (hereinafter, sometimes referred to as "solvent (D)"), and other components (hereinafter, sometimes referred to as "other components (F)").

[0011] The negative resist composition of the present invention contains a resin (A1) and may further contain an alkali-soluble resin. The alkali-soluble resin is a resin that has an acidic group (sometimes referred to as a hydrophilic group) and is soluble in an alkaline developer. Examples of the acidic group include a carboxy group, a sulfo group, and a hydroxy group (such as a phenolic hydroxy group). Examples of the alkali-soluble resin include alkali-soluble resins known in the resist field, such as novolak resins (A2), resins containing the structural unit (a2-1) but not the structural unit (a2-4), resins containing a structural unit derived from a (meth)acrylic acid ester, and polyalkylene glycols.

[0012] <Resin (A1)> The resin (A1) is a resin containing the structural unit (a2-1) and the structural unit (a2-4), and is an alkali-soluble resin. TIFF2025181636000005.tif48170[In formula (a2-1) and formula (a2-4), R a7 , and R a13 each independently represents a hydrogen atom or a methyl group. R a10 , and R a14 are each independently an alkyl group having 1 to 6 carbon atoms. R a15 represents a hydrocarbon group having 1 to 12 carbon atoms. m 1 represents an integer between 0 and 4. 1 When is 2 or more, multiple R a10 may be the same or different from each other. m 2 represents an integer of 1 to 4. However, m 1 and m 2 The sum of these is 5 or less. m 3 represents an integer between 0 and 4. 3 When is 2 or more, multiple R a14 may be the same or different from each other. m 4 represents an integer of 1 to 4. 4 When is 2 or more, multiple R a15 may be the same or different from each other. However, m 3 and m 4 The sum of is 5 or less.]

[0013] R a15Examples of hydrocarbon groups having 1 to 12 carbon atoms represented by the formula (I) include linear or branched chain hydrocarbon groups having 1 to 12 carbon atoms (particularly alkyl groups having 1 to 12 carbon atoms, alkenyl groups having 2 to 12 carbon atoms, and alkynyl groups having 2 to 12 carbon atoms), alicyclic hydrocarbon groups having 3 to 12 carbon atoms, aromatic hydrocarbon groups having 6 to 12 carbon atoms, and groups having 4 to 12 carbon atoms formed by combining these groups. Among these, groups in which the carbon atom bonded to the oxygen atom is a tertiary carbon atom are excluded. A methylene group contained in the hydrocarbon group having 1 to 12 carbon atoms may be substituted with an oxygen atom or a carbonyl group. However, a methylene group bonded to an oxygen atom and a methylene group bonded to the methylene group are not substituted with an oxygen atom. R a15 As the alkyl group, an alkyl group having 1 to 6 carbon atoms is preferred, an alkyl group having 1 to 4 carbon atoms is more preferred, and a methyl group, an ethyl group, and a propyl group are even more preferred.

[0014] In the resin (A1), the content of the structural unit (a2-1) is preferably from 10 to 90 mol %, more preferably from 20 to 85 mol %, based on all structural units in the resin (A1). In the resin (A1), the content of the structural unit (a2-4) is preferably from 3 to 40 mol %, more preferably from 5 to 30 mol %, and even more preferably from 10 to 25 mol %, based on all structural units in the resin (A1).

[0015] Resin (A1) may contain structural units other than the structural units (a2-1) and (a2-4). Examples of such structural units include structural units of monomers in which the hydroxy group of hydroxystyrene has been substituted with another group, and structural units of monomers having an α,β-unsaturated double bond. Examples of monomers that form such structural units include styrene-based monomers such as styrene, chlorostyrene, and α-methylstyrene; acrylic acid monomers such as acrylic acid, methacrylic acid, methyl acrylate, and methyl methacrylate; and vinyl acetate-based monomers such as vinyl acetate and vinyl benzoate.

[0016] Resin (A1) can be produced, for example, by the method described in JP-A-7-295220.

[0017] The weight-average molecular weight of resin (A1) is preferably 1,000 or more, more preferably 1,500 or more, even more preferably 2,000 or more, and preferably 10,000 or less, more preferably 8,000 or less, even more preferably 5,000 or less. The weight-average molecular weight is determined by gel permeation chromatography analysis as a value converted to standard polystyrene. Detailed analysis conditions for this analysis are described in the Examples of the present application.

[0018] <Novolac resin (A2)> The novolak resin (A2) is a resin obtained by condensing a phenol compound with an aldehyde in the presence of a catalyst, and is, for example, a resin containing a structural unit represented by the following formula (a4). TIFF2025181636000006.tif30170[In formula (a4), R a45 represents a halogen atom, a carboxy group, an alkyl group having 1 to 6 carbon atoms, a haloalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 12 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or a methacryloyloxy group. na4 represents an integer of 1 to 4. na41 represents an integer of 0 to 3, and when na41 is 2 or more, a plurality of R a45 may be the same or different, provided that 1≦na4+na41≦4 is satisfied.

[0019] In formula (a4), R a45 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R a45The alkyl group having 1 to 6 carbon atoms may be a linear or branched alkyl group, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. R a45 Examples of the haloalkyl group having 1 to 6 carbon atoms include groups in which a hydrogen atom contained in the above alkyl group is replaced with the above halogen atom, such as a fluorinated alkyl group having 1 to 6 carbon atoms, a chlorinated alkyl group having 1 to 6 carbon atoms, a brominated alkyl group having 1 to 6 carbon atoms, or an iodinated alkyl group having 1 to 6 carbon atoms, and among these, a perfluoroalkyl group having 1 to 3 carbon atoms is preferred. R a45 Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, and a tert-butoxy group. The number of carbon atoms in the alkoxy group is preferably 1 to 4, more preferably 1 to 3, still more preferably a methoxy group or an ethoxy group, and even more preferably a methoxy group. R a45 Examples of the alkoxyalkyl group having 2 to 12 carbon atoms include a methoxymethyl group, an ethoxyethyl group, a propoxymethyl group, an isopropoxymethyl group, a butoxymethyl group, a sec-butoxymethyl group, and a tert-butoxymethyl group. The alkoxyalkyl group is preferably an alkoxyalkyl group having 2 to 8 carbon atoms, more preferably a methoxymethyl group or an ethoxyethyl group, and even more preferably a methoxymethyl group. R a45 Examples of the alkoxyalkoxy group having 2 to 12 carbon atoms include a methoxymethoxy group, a methoxyethoxy group, an ethoxymethoxy group, an ethoxyethoxy group, a propoxymethoxy group, an isopropoxymethoxy group, a butoxymethoxy group, a sec-butoxymethoxy group, and a tert-butoxymethoxy group. The alkoxyalkoxy group is preferably an alkoxyalkoxy group having 2 to 8 carbon atoms, and more preferably a methoxyethoxy group or an ethoxyethoxy group. R a45Examples of the alkylcarbonyl group having 2 to 4 carbon atoms include an acetyl group, a propionyl group, a butyryl group, etc. The alkylcarbonyl group is preferably an alkylcarbonyl group having 2 to 3 carbon atoms, and more preferably an acetyl group. R a45 Examples of the alkylcarbonyloxy group having 2 to 4 carbon atoms include an acetyloxy group, a propionyloxy group, and a butyryloxy group. The alkylcarbonyloxy group is preferably an alkylcarbonyloxy group having 2 to 3 carbon atoms, and more preferably an acetyloxy group. In formula (a4), Ra 45 is preferably an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, even more preferably a methyl group, an ethyl group, a methoxy group or an ethoxy group, and even more preferably a methyl group or a methoxy group.

[0020] na4 is preferably 1 or 2, and more preferably 1. na41 is preferably 0, 1 or 2, and more preferably 0 or 1.

[0021] The novolak resin (A2) preferably has a weight-average molecular weight of 3,000 or more, more preferably 4,000 or more, even more preferably 5,000 or more, even more preferably 6,000 or more, and preferably 100,000 or less, more preferably 50,000 or less, even more preferably 10,000 or less, even more preferably 9,000 or less, and even more preferably 8,000 or less. By setting the weight-average molecular weight within this range, thinning and residue remaining after development can be effectively prevented. The weight-average molecular weight is determined by gel permeation chromatography analysis as a converted value based on standard polystyrene. Detailed analytical conditions for this analysis are described in the Examples of this application.

[0022] The content of resin (A2) relative to the total amount of resins contained in the negative resist composition is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, and even more preferably 65% ​​by mass or less.

[0023] <Resin containing structural units derived from (meth)acrylic acid ester> Examples of resins containing structural units derived from (meth)acrylic acid esters include those obtained by using the following compounds as monomers and polymerizing one or more of these monomers in combination by a conventional method. Examples of resins containing structural units derived from (meth)acrylic acid esters include resins containing structural units derived from the following monomers. Monomers having a carboxy group such as (meth)acrylic acid; monomers having a hydroxy group such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; and monomers having multiple ether bonds such as polyethylene glycol monomethyl ether (meth)acrylates (polyalkylene glycol monoalkyl ether (meth)acrylates) such as diethylene glycol monomethyl ether (meth)acrylate, triethylene glycol monomethyl ether (meth)acrylate, tetraethylene glycol monomethyl ether (meth)acrylate, pentaethylene glycol monomethyl ether (meth)acrylate, hexaethylene glycol monomethyl ether (meth)acrylate, heptaethylene glycol monomethyl ether (meth)acrylate, octaethylene glycol monomethyl ether (meth)acrylate, and nonaethylene glycol monomethyl ether (meth)acrylate.

[0024] The above-mentioned monomers may be used in combination with (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, tert-butyl (meth)acrylate, and hexyl (meth)acrylate; (meth)acrylic acid cycloalkyl esters such as cyclopentyl (meth)acrylate and cyclohexyl (meth)acrylate; monocyclic (meth)acrylic acid esters such as adamantyl (meth)acrylate and norbornyl (meth)acrylate; (meth)acrylic acid aryl esters such as phenyl (meth)acrylate and benzyl (meth)acrylate; and ethylene glycol monoalkyl ether (meth)acrylates (alkylene glycol monoalkyl ether (meth)acrylates) such as ethylene glycol monomethyl ether (meth)acrylate, ethylene glycol monoethyl ether (meth)acrylate, ethylene glycol monopropyl ether (meth)acrylate, and ethylene glycol monobutyl ether (meth)acrylate. In addition to the above monomers, styrenes such as styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene, and 4-isopropoxystyrene; carboxylic acids such as crotonic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid; and the hydroxystyrenes exemplified in the resin containing the structural unit derived from hydroxystyrene described above may also be used in combination. Examples of structural units derived from such monomers include structural units represented by formulae (a2-1) to (a2-4).

[0025] <Polyalkylene glycol> Polyalkylene glycols are polymers obtained by addition polymerization of alkylene oxides to alcohols. Examples of alcohols include butanol, ethylene glycol, propylene glycol, glycerin, and pentaerythritol. Examples of alkylene oxides include ethylene oxide, propylene oxide, and butylene oxide. Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, and polybutylene glycol.

[0026] <Acid generator (B)> The acid generator (B) is a compound that can be decomposed by light irradiation (exposure) to generate an acid. The generated acid acts as an acid catalyst that promotes the crosslinking reaction, and the crosslinker bonds with the reactive groups in the resin to form crosslinks. In other words, by exposing a negative resist composition containing the resin (A1), it can be made insoluble in a resist developer (an alkaline aqueous solution).

[0027] The acid generator (B) contains at least two types of acid generators having a group represented by formula (B1), at least one of which is a compound represented by formula (b1). TIFF2025181636000007.tif22170[In formula (B1), R b1 represents a hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom, and a methylene group contained in the hydrocarbon group may be substituted with an oxygen atom or a carbonyl group. * represents a bond.]

[0028] R b1 Examples of the hydrocarbon group having 1 to 18 carbon atoms in the hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom include linear or branched chain hydrocarbon groups having 1 to 18 carbon atoms, alicyclic hydrocarbon groups having 3 to 18 carbon atoms, aromatic hydrocarbon groups having 6 to 18 carbon atoms, and groups having 4 to 18 carbon atoms which are combinations of these groups. The linear or branched chain hydrocarbon group having 1 to 18 carbon atoms is preferably an alkyl group having 1 to 18 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, or a decyl group. Of these, linear groups are preferred. Examples of the alicyclic hydrocarbon group having 3 to 18 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and an adamantyl group. The aromatic hydrocarbon group having 6 to 18 carbon atoms is preferably an aryl group having 6 to 18 carbon atoms, and examples thereof include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, and a phenanthryl group.

[0029] Among the groups having 4 to 18 carbon atoms formed by combining the above groups, examples of the group (group having 4 to 18 carbon atoms) formed by combining a chain hydrocarbon group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, an isobornyl group, a 2-alkyladamantan-2-yl group, and a 1-(adamantan-1-yl)alkane-1-yl group. Examples of groups in which a chain hydrocarbon group and an aromatic hydrocarbon group are combined (groups having 7 to 18 carbon atoms) include aralkyl groups and aromatic hydrocarbon groups having an alkyl group, and specific examples thereof include benzyl, phenethyl, phenylpropyl, trityl, naphthylmethyl, naphthylethyl, p-methylphenyl, p-tert-butylphenyl, tolyl, xylyl, cumenyl, mesityl, 2,6-diethylphenyl, and 2-methyl-6-ethylphenyl groups. Examples of groups in which an alicyclic hydrocarbon group and an aromatic hydrocarbon group are combined (groups having 9 to 18 carbon atoms) include aromatic hydrocarbon groups having an alicyclic hydrocarbon group and alicyclic hydrocarbon groups having an aromatic hydrocarbon group, and specific examples include a p-cyclohexylphenyl group, a p-adamantylphenyl group, and a phenylcyclohexyl group.

[0030] R b1Of the hydrocarbon groups having 1 to 18 carbon atoms represented by the formula (I), an alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms is preferred, an alkyl group having 1 to 8 carbon atoms is more preferred, and an alkyl group having 1 to 4 carbon atoms is even more preferred.

[0031] R b1 Examples of the group in which a methylene group contained in an alicyclic hydrocarbon group having 3 to 18 carbon atoms is substituted with an oxygen atom or a carbonyl group include groups represented by formulae (Y1) to (Y12). Preferred are groups represented by formulae (Y7) to (Y9), and more preferred is a group represented by formula (Y9). TIFF2025181636000008.tif53170

[0032] The fluorine atom-containing hydrocarbon group having 1 to 18 carbon atoms is a group in which one or more hydrogen atoms contained in the above-mentioned hydrocarbon group having 1 to 18 carbon atoms have been substituted with a fluorine atom, and specific examples include fluoroalkyl groups such as a fluoromethyl group, a fluoroethyl group, a fluoropropyl group, a fluorobutyl group, a fluoropentyl group, a fluorohexyl group, a fluoroheptyl group, a fluorooctyl group, a fluorononyl group, and a fluorodecyl group; fluorocycloalkyl groups such as a fluorocyclopropyl group, a fluorocyclobutyl group, a fluorocyclopentyl group, a fluorocyclohexyl group, a fluorocycloheptyl group, a fluorocyclooctyl group, and a fluoroadamantyl group; and fluoroaryl groups such as a fluorophenyl group, a fluoronaphthyl group, and a fluoroanthryl group.

[0033] The hydrocarbon group having 1 to 18 carbon atoms and having a fluorine atom is preferably an alkyl group having 1 to 10 carbon atoms and having a fluorine atom, or an aromatic hydrocarbon group having 6 to 10 carbon atoms and having a fluorine atom, more preferably a perfluoroalkyl group having 1 to 8 carbon atoms, and even more preferably a perfluoroalkyl group having 1 to 4 carbon atoms.

[0034] At least one of the at least two acid generators having a group represented by formula (B1) is a compound represented by formula (b1). TIFF2025181636000009.tif36170[In formula (b1), R b1 represents the same meaning as above. R b2 represents a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a thioalkyl group having 1 to 8 carbon atoms. Ring W b1 represents an aromatic hydrocarbon ring having 6 to 14 carbon atoms or an aromatic heterocyclic ring having 6 to 14 carbon atoms. x represents an integer of 0 to 6. When x is 2 or more, a plurality of R b2 may be the same or different.]

[0035] R b2 The hydrocarbon group having 1 to 8 carbon atoms represented by the formula (I) may be linear or branched, and includes an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, and an alkynyl group having 1 to 8 carbon atoms. An alkyl group having 1 to 8 carbon atoms is preferred, an alkyl group having 1 to 6 carbon atoms is more preferred, and an alkyl group having 1 to 4 carbon atoms is even more preferred. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group.

[0036] R b2 Examples of the alkoxy group having 1 to 8 carbon atoms represented by the formula (I) include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentyloxy group. R b2 Examples of the thioalkyl group having 1 to 8 carbon atoms represented by the formula (I) include a thiomethyl group, a thioethyl group, a thiopropyl group, a thiobutyl group, and a thiopentyl group.

[0037] Ring W b1 Examples of the aromatic hydrocarbon ring having 6 to 14 carbon atoms represented by the formula: include a benzene ring, a naphthalene ring, and an anthracene ring. Ring W b1 Examples of the aromatic heterocyclic ring having 6 to 14 carbon atoms represented by the following formula include rings having 6 to 14 atoms constituting the ring, and preferred examples include the following rings. TIFF2025181636000010.tif24170 Ring W b1 is preferably a naphthalene ring.

[0038] The compound represented by formula (b1) is preferably a compound represented by any one of formulas (b4) to (b7), and more preferably a compound represented by formula (b4). TIFF2025181636000011.tif101170

[0039] [In formulas (b4) to (b7), R b1 , R b2 and x have the same meaning as above. y represents an integer of 0 to 4; z represents an integer of 0 to 2; X b1 and X b2 each independently represents -O-, -S- or -CO-.

[0040] Examples of the compound represented by formula (b1) include compounds represented by formulas (b1-1) to (b1-24). Preferred are compounds represented by formulas (b1-6) to (b1-10), (b1-13) to (b1-15), and (b1-20) to (b1-22).

[0041] TIFF2025181636000012.tif199170

[0042] TIFF2025181636000013.tif106170

[0043] The at least two acid generators having a group represented by formula (B1) contained in acid generator (B) may also contain compounds other than the compound represented by formula (b1), such as compounds represented by formula (b2) and (b3). TIFF2025181636000014.tif44170 [In formula (b2) and formula (b3), R b1 represents the same meaning as above. R b3 and R b4 each independently represents a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a thioalkyl group having 1 to 8 carbon atoms.]

[0044] R b3 and R b4 As the hydrocarbon group having 1 to 8 carbon atoms represented by the formula (I), R b2 Examples include the same hydrocarbon groups having 1 to 8 carbon atoms as those represented by the following formula: R b3 and R b4 As the alkoxy group having 1 to 8 carbon atoms represented by the formula (I), R b2 Examples of the alkoxy group include the same alkoxy groups having 1 to 8 carbon atoms as those represented by the following formula: R b3 and R b4 As the thioalkyl group having 1 to 8 carbon atoms represented by the formula (I), R b2 Examples include the same thioalkyl groups having 1 to 8 carbon atoms as those represented by the following formula:

[0045] Examples of the compound represented by formula (b2) include compounds represented by the following formulas: TIFF2025181636000015.tif79170

[0046] Examples of the compound represented by formula (b3) include compounds represented by the following formulas: TIFF2025181636000016.tif28170

[0047] At least one compound selected from the compounds represented by formula (b1) contained in the acid generator (B) is preferably a compound in which x is 1. b2 is preferably a hydrocarbon group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 8 carbon atoms.

[0048] Preferred examples of the acid generator (B) include those containing the following combinations: (i) a combination of at least two compounds selected from compounds represented by formula (b1), or (ii) A combination of at least one compound selected from the compounds represented by formula (b1) and at least one compound selected from the compounds represented by formula (b2) and formula (b3).

[0049] Among the combinations of (i) above, a compound represented by formula (b1) (wherein x is 1, R b1 , R b2 and W b1 has the same meaning as above), and a compound represented by formula (b1) (wherein x is 0). Ra4 and W b1 has the same meaning as above.)

[0050] Other preferred combinations of the above (i) include combinations of at least two compounds selected from the compounds represented by formulae (b4) to (b7).

[0051] Another preferred combination of the above (i) is a combination of at least two compounds selected from the compounds represented by formula (b4).

[0052] Another preferred combination of the above (i) is a compound represented by formula (b4) (wherein x is 0. R b1 and R b2 has the same meaning as above), and a compound represented by formula (b4) (wherein x is 1; R b1 and R b2 has the same meaning as above.)

[0053] Another preferred combination of the above (i) is a combination of at least one selected from formulae (b1-1) to (b1-11) and at least one selected from formulae (b1-12) to (b1-24).

[0054] A preferred example of the combination (ii) above is a combination of at least one compound selected from the compounds represented by formula (b4) and at least one compound selected from the compounds represented by formula (b2) and formula (b3).

[0055] Another preferred combination of the above (ii) is a combination of a compound represented by formula (b4) and at least one compound selected from the group consisting of compounds represented by formula (b2).

[0056] Another preferred combination of the above (ii) is a combination of at least one selected from formulas (b1-1) to (b1-24) and at least one selected from formulas (b2-1) to (b2-6) and formulas (b3-1) to (b3-3).

[0057] Another preferred combination of the above (ii) is a combination of at least one selected from formulae (b1-1) to (b1-24) and at least one selected from formulae (b2-1) to (b2-6).

[0058] The acid generator (B) used in the present invention essentially contains at least two types of acid generators having a group represented by formula (B1) as described above (at least one of the acid generators is a compound represented by formula (b1)), but may also contain an acid generator other than the two acid generators (such as a nonionic acid generator or an ionic acid generator) within a range that does not adversely affect the effects of the present invention. For example, examples of nonionic acid generators include organic halides, sulfonate esters (e.g., 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonyloxy). phenates), sulfones (for example, disulfone, ketosulfone, sulfonyldiazomethane), etc. (however, the acid generator contained as an essential component in the present invention is excluded). Typical examples of ionic acid generators include onium salts containing onium cations (e.g., diazonium salts, phosphonium salts, sulfonium salts, and iodonium salts). Examples of anions of onium salts include sulfonate anions, sulfonylimide anions, and sulfonylmethide anions.

[0059] Examples of the acid generator include compounds that generate an acid when exposed to radiation, such as those described in JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, JP-A-62-153853, JP-A-63-146029, U.S. Pat. No. 3,779,778, U.S. Pat. No. 3,849,137, German Patent No. 3,914,407, and European Patent No. 126,712. Compounds produced by known methods may also be used. The acid generator (B) may be used singly or in combination of two or more.

[0060] The ionic acid generator is preferably a compound represented by formula (b8) or formula (b9). TIFF2025181636000017.tif36170 [In formula (b8) and formula (b9), A b1 and A b2 represent each independently an oxygen atom or a sulfur atom. R b8 , R b9 , R b10 and R b11 are each independently an alkyl group having 1 to 10 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms. X1 - and X2 - represents an organic anion.

[0061] Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Examples of aromatic hydrocarbon groups having 6 to 12 carbon atoms include aryl groups such as phenyl, naphthyl, anthryl, biphenyl, and phenanthryl. The aromatic hydrocarbon group may further have a substituent, and examples of the aromatic hydrocarbon group having a substituent include an aralkyl group and an aromatic hydrocarbon group having an alkyl group, and specific examples include a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, a naphthylethyl group, a p-methylphenyl group, a p-tert-butylphenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a 2,6-diethylphenyl group, and a 2-methyl-6-ethylphenyl group. R b8 , R b9 , R b10 and R b11 are each preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms, more preferably a phenyl group.

[0062] X1 - and X2 - Examples of the organic anion represented by formula (b10) include a sulfonate anion, a bis(alkylsulfonyl)amide anion, and a tris(alkylsulfonyl)methide anion. Of these, a sulfonate anion is preferred, and a sulfonate anion represented by formula (b10) is more preferred. TIFF2025181636000018.tif20170[In formula (b10), R b12 represents a hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom, and a methylene group contained in the hydrocarbon group may be substituted with an oxygen atom or a carbonyl group.] R b12 As for R in formula (B1), b1 The same groups as those shown below can be mentioned.

[0063] Examples of the compound represented by formula (b8) include the following compounds. TIFF2025181636000019.tif101170

[0064] Examples of the compound represented by formula (b9) include the following compounds. TIFF2025181636000020.tif61170

[0065] The total content of the acid generator (B) in the negative resist composition of the present invention is preferably from 0.1 to 40 parts by mass, more preferably from 0.5 to 30 parts by mass, even more preferably from 1 to 20 parts by mass, and even more preferably from 1 to 5 parts by mass, relative to 100 parts by mass of the resin.

[0066] The content of the at least two acid generators having a group represented by formula (B1) (at least one of the acid generators is a compound represented by formula (b1)) contained in the acid generator (B) used in the present invention is usually 30 to 100 mass%, preferably 40 to 100 mass%, more preferably 50 to 100 mass%, and particularly preferably 60 to 100 mass%.

[0067] In the acid generator (B) used in the present invention, the content of the compound represented by formula (b1) contained in at least two types of acid generators having a group represented by formula (B1) is usually 20 to 100 mass%, preferably 30 to 100 mass%, more preferably 40 to 100 mass%, and particularly preferably 50 to 100 mass%.

[0068] <Crosslinking agent (E)> The crosslinking agent (E) is a compound that bonds with the resin (A1) when the acid generator (B) decomposes upon exposure to light and the acid generated is reacted with the compound to form a crosslinked structure. Examples of the crosslinking agent include a melamine-based crosslinking agent, a urea-based crosslinking agent, an alkylene urea-based crosslinking agent, and a glycoluril-based crosslinking agent.

[0069] The melamine-based crosslinking agent includes a compound represented by formula (e1). TIFF2025181636000021.tif33170[In formula (e1), R e1 represent each independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. R e2 are each independently a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or -CH-OR e1 Represents. R e3 represents a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or a group represented by formula (e1-1). TIFF2025181636000022.tif17170[In formula (e1-1), R e1 , and R e2 represents the same group as in formula (e1).

[0070] Specific examples of melamine-based crosslinking agents include N,N,N,N,N,N-hexakis(methoxymethyl)melamine, N,N,N,N,N,N-hexakis(ethoxymethyl)melamine, N,N,N,N,N,N-hexakis(propoxymethyl)melamine, N,N,N,N,N,N,N-hexakis(isopropoxymethyl)melamine, N,N,N,N,N,N,N-hexakis(butoxymethyl)melamine, and N,N,N,N,N,N -Hexakis(t-butoxymethyl)melamine, N,N,N,N,N,N-Hexakis(cyclohexyloxymethyl)melamine, N,N,N,N,N,N,N-Hexakis(cyclopentyloxymethyl)melamine, N,N,N,N,N,N,N-Hexakis(adamantyloxymethyl)melamine, N,N,N,N,N,N,N-Hexakis(norbornyloxymethyl)melamine, N,N,N,N,N-Tetrakis(methoxy N,N,N,N-Tetrakis(ethoxymethyl)acetoguanamine, N,N,N,N-Tetrakis(propoxymethyl)acetoguanamine, N,N,N,N-Tetrakis(isopropoxymethyl)acetoguanamine, N,N,N,N-Tetrakis(butoxymethyl)acetoguanamine, N,N,N,N-Tetrakis(t-butoxymethyl)acetoguanamine, N,N,N,N-Tetrakis (methoxymethyl)benzoguanamine, N,N,N,N-tetrakis(ethoxymethyl)benzoguanamine, N,N,N,N-tetrakis(propoxymethyl)benzoguanamine, N,N,N,N-tetrakis(isopropoxymethyl)benzoguanamine, N,N,N,N-tetrakis(butoxymethyl)benzoguanamine, N,N,N,N-tetrakis(t-butoxymethyl)benzoguanamine, and the like.

[0071] The urea-based crosslinking agent includes a compound represented by formula (e2). TIFF2025181636000023.tif22170[In formula (e2), R e1 , and R e2 represents the same group as in formula (e1). Specific examples of urea-based crosslinking agents include N,N-di(methoxymethyl)urea, N,N-di(ethoxymethyl)urea, N,N-di(propoxymethyl)urea, N,N-di(isopropoxymethyl)urea, N,N-di(butoxymethyl)urea, N,N-di(t-butoxymethyl)urea, N,N-di(cyclohexyloxymethyl)urea, N,N-di(cyclopentyloxymethyl)urea, N,N-di(adamantyloxymethyl)urea, and N,N-di(norbornyloxymethyl)urea.

[0072] The alkylene urea crosslinking agent includes a compound represented by formula (e3). TIFF2025181636000024.tif30170[In formula (e3), R e1 represents the same group as in formula (e1). R e3 each independently represents a hydrogen atom, a hydroxyl group, a hydrocarbon group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. xe represents an integer of 0 to 2.

[0073] Specific examples of alkylene urea crosslinking agents include N,N-di(methoxymethyl)-4,5-di(methoxymethyl)ethyleneurea, N,N-di(ethoxymethyl)-4,5-di(ethoxymethyl)ethyleneurea, N,N-di(propoxymethyl)-4,5-di(propoxymethyl)ethyleneurea, N,N-di(isopropoxymethyl)-4,5-di(isopropoxymethyl)ethyleneurea, N,N-di(butoxymethyl)-4,5-di(butoxymethyl)ethyleneurea, and N,N-di(t-butoxymethyl)ethyleneurea.

[0033] Examples thereof include N,N-di(dimethyl)-4,5-di(t-butoxymethyl)ethyleneurea, N,N-di(cyclohexyloxymethyl)-4,5-di(cyclohexyloxymethyl)ethyleneurea, N,N-di(cyclopentyloxymethyl)-4,5-di(cyclopentyloxymethyl)ethyleneurea, N,N-di(adamantyloxymethyl)-4,5-di(adamantyloxymethyl)ethyleneurea, and N,N-di(norbornyloxymethyl)-4,5-di(norbornyloxymethyl)ethyleneurea.

[0074] An example of the glycoluril crosslinking agent is represented by formula (e4). TIFF2025181636000025.tif38170[In formula (e4), R e1 represents the same group as in formula (e1). R e4 each independently represents a hydrogen atom, a hydroxyl group, a hydrocarbon group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.]

[0075] Specific examples of glycoluril-based crosslinking agents include N,N,N,N-tetra(methoxymethyl)glycoluril, N,N,N,N-tetra(ethoxymethyl)glycoluril, N,N,N,N-tetra(propoxymethyl)glycoluril, N,N,N,N-tetra(isopropoxymethyl)glycoluril, N,N,N,N-tetra(butoxymethyl)glycoluril, N,N,N,N-tetra(t-butoxymethyl)glycoluril, N,N,N,N-tetra(cyclohexyloxymethyl)glycoluril, N,N,N,N-tetra(cyclopentyloxymethyl)glycoluril, N,N,N,N-tetra(adamantyloxymethyl)glycoluril, and N,N,N,N-tetra(norbornyloxymethyl)glycoluril.

[0076] Among the above, the crosslinking agent (E) is preferably a melamine-based crosslinking agent or a glycoluril-based crosslinking agent. The crosslinking agent (E) may be used alone or in combination of two or more.

[0077] In the negative resist composition of the present invention, the content of the crosslinking agent (E) is preferably 1 to 50 parts by mass, more preferably 2 to 40 parts by mass, and even more preferably 3 to 30 parts by mass, per 100 parts by mass of the resin.

[0078] <Solvent (D)> The content of solvent (D) in the negative resist composition is usually 45% by mass or more, preferably 50% by mass or more, more preferably 55% by mass or more, and usually 99.9% by mass or less, preferably 99% by mass or less, more preferably 90% by mass or less. The content of solvent (E) can be measured by known analytical means, for example, liquid chromatography or gas chromatography.

[0079] Examples of the solvent (D) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate, and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; esters such as ethyl lactate, butyl acetate, amyl acetate, and ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone, and cyclohexanone; and cyclic esters such as γ-butyrolactone. The solvent (D) may be contained either alone or in combination of two or more.

[0080] <Quencher (C)> The negative resist composition of the present invention may contain a quencher (hereinafter, may be referred to as "quencher (C)"). The quencher (C) is a compound that has the effect of capturing the acid generated from the acid generator upon exposure. Examples of the quencher (C) include basic nitrogen-containing organic compounds. Examples of the basic nitrogen-containing organic compounds include amines and ammonium salts. Examples of the amines include aliphatic amines (including primary amines, secondary amines, and tertiary amines), aromatic amines, etc.

[0081] Examples of the amine include compounds represented by formula (C1) or formula (C2). TIFF2025181636000026.tif20170[In formula (C1), R c1 , R c2 and R c3represent each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms, and the alkyl group having 1 to 6 carbon atoms and the alicyclic hydrocarbon group having 3 to 10 carbon atoms may have at least one group selected from the group consisting of a hydroxy group, an amino group, and an alkoxy group having 1 to 6 carbon atoms, and the aromatic hydrocarbon group having 6 to 10 carbon atoms may have at least one group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alicyclic hydrocarbon group having 3 to 10 carbon atoms.

[0082] Examples of the compound represented by formula (C1) include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N,N-dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, dibutylmethylamine, ... Examples of the amine include ethyldipentylamine, dihexylmethylamine, dicyclohexylmethylamine, diheptylmethylamine, methyldioctylamine, methyldinonylamine, didecylmethylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, etc. Diisopropylaniline is preferred, and 2,6-diisopropylaniline is particularly preferred.

[0083] TIFF2025181636000027.tif17170[In formula (C2), Ring W 1 represents a heterocycle containing a nitrogen atom as a ring-constituting atom, or a benzene ring having a substituted or unsubstituted amino group, and the heterocycle and the benzene ring may have at least one group selected from the group consisting of a hydroxy group and an alkyl group having 1 to 4 carbon atoms. A 1 represents a phenyl group or a naphthyl group. nc represents 2 or 3, and a plurality of A 1 may be the same or different.]

[0084] The substituted or unsubstituted amino group is —N(R 4 )(R 5 ) and R 4 and R 5 are each independently a hydrogen atom, a chain hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms. Examples of the chain hydrocarbon group having 1 to 10 carbon atoms include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl groups. Examples of the alicyclic hydrocarbon group having 3 to 10 carbon atoms include monocyclic alicyclic hydrocarbon groups such as cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group; and polycyclic alicyclic hydrocarbon groups such as a decahydronaphthyl group, an adamantyl group, and a norbornyl group. Examples of aromatic hydrocarbon groups having 6 to 14 carbon atoms include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, and a phenanthryl group. The aromatic hydrocarbon group may further have a substituent, and examples of the substituent include an aryloxy group having 6 to 10 carbon atoms.

[0085] A heterocycle containing a nitrogen atom as one of the atoms constituting the ring may be an aromatic ring or a non-aromatic ring, and may contain other heteroatoms (e.g., oxygen atoms, sulfur atoms) in addition to the nitrogen atom. The number of nitrogen atoms contained in the heterocycle is, for example, 1 to 3. Examples of the heterocycle include rings represented by any of formulas (Y13) to (Y28). When one of the hydrogen atoms contained in the ring is removed, A 1 It becomes a combination with. TIFF2025181636000028.tif57170

[0086] Ring W 1 is preferably a heterocyclic ring containing a nitrogen atom as an atom constituting the ring, more preferably a 5- or 6-membered aromatic heterocyclic ring containing a nitrogen atom as an atom constituting the ring, and even more preferably a ring represented by any one of formulae (Y20) to (Y25).

[0087] Examples of the compound represented by formula (C2) include compounds represented by any of formulas (C2-1) to (C2-11). Preferred are compounds represented by any of formulas (C2-2) to (C2-8). TIFF2025181636000029.tif87170

[0088] The content of the quencher (C) in the solid content of the negative resist composition is preferably from 0.0001 to 5 mass%, more preferably from 0.0001 to 4 mass%, even more preferably from 0.001 to 3 mass%, even more preferably from 0.01 to 1.0 mass%, and even more preferably from 0.1 to 0.7 mass%.

[0089] <Other ingredients> The negative resist composition of the present invention may optionally contain components other than those described above (hereinafter, these may be referred to as "other components (F)"). There are no particular restrictions on the other components (F), and additives known in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, and adhesion improvers, can be used. When other component (F) is used, the content thereof is appropriately selected depending on the type of other component (F).

[0090] 2. Preparation of negative resist composition The negative resist composition of the present invention can be prepared by mixing resin (A1), crosslinking agent (E), acid generator (B), and, if necessary, resins other than resin (A1), quencher (C), solvent (D), and other components (F). The order of mixing is arbitrary and is not particularly limited. The temperature during mixing is, for example, 10 to 40°C, and an appropriate temperature can be selected depending on the type of resin, etc., the solubility of the resin, etc. in the solvent (D), etc. The mixing time can be selected from the range of 0.5 to 24 hours depending on the mixing temperature. The mixing means is also not particularly limited, and stirring and mixing can be used. After mixing the components, it is preferable to filter the mixture using a filter with a pore size of about 0.003 to 50 μm.

[0091] 3. Resist pattern manufacturing method The method for producing a resist pattern of the present invention comprises: (1) applying the negative resist composition of the present invention onto a substrate; (2) a step of drying the coated negative resist composition to form a composition layer; (3) exposing the composition layer to light; and (4) A step of heating and developing the composition layer after exposure.

[0092] The negative resist composition can be applied to a substrate using a commonly used device such as a spin coater. Examples of the substrate include inorganic substrates such as silicon wafers, and semiconductor elements (e.g., transistors, diodes, etc.) may be formed on the substrate in advance. The applied composition is dried to remove the solvent and form a composition layer. Drying is carried out, for example, by evaporating the solvent using a heating device such as a hot plate (so-called pre-baking), or by using a vacuum device. The heating temperature is preferably 50 to 200°C, and the heating time is preferably 30 to 600 seconds. The pressure during vacuum drying is preferably 1 to 1.0 × 10 5 It is preferable that the pressure is about Pa. After drying, the film thickness of the resulting composition is preferably 1 to 50 μm, more preferably 1.5 to 30 μm.

[0093] The resulting composition layer is typically exposed using an exposure device. Examples of exposure light sources include light sources emitting light with wavelengths of 345 to 436 nm (g-line (wavelength: 436 nm), h-line (wavelength: 405 nm), i-line (wavelength: 365 nm)), light sources emitting ultraviolet laser light such as KrF excimer laser (wavelength: 248 nm), ArF excimer laser (wavelength: 193 nm), and F2 excimer laser (wavelength: 157 nm), light sources that convert the wavelength of laser light from a solid-state laser light source (such as a YAG or semiconductor laser) to emit harmonic laser light in the far ultraviolet or vacuum ultraviolet region, and light sources that irradiate electron beams or extreme ultraviolet (EUV) light. In this specification, irradiation with these types of radiation may be collectively referred to as "exposure." During exposure, exposure is typically performed through a mask corresponding to the desired pattern. When the exposure light source is an electron beam, exposure may be performed by direct writing without using a mask. The composition layer after exposure may be subjected to a heat treatment (so-called post-exposure bake) to promote the crosslinking reaction between the resin and the crosslinking agent. The heating temperature is usually about 50 to 200° C., preferably about 70 to 150° C. The heating time is usually 40 to 400 seconds, preferably 50 to 350 seconds.

[0094] The heated composition layer is usually developed using a developing device and a developer. Examples of the development method include a dipping method, a puddle method, a spray method, and a dynamic dispensing method. The development temperature is preferably, for example, 5 to 60°C, and the development time is preferably, for example, 5 to 600 seconds.

[0095] The negative resist composition of the present invention uses an alkaline developer as a developer. The alkaline developer may be any of various alkaline aqueous solutions used in this field. Examples include aqueous solutions of tetramethylammonium hydroxide and (2-hydroxyethyl)trimethylammonium hydroxide (commonly known as choline). The alkaline developer may contain a surfactant. After development, the resist pattern is preferably washed with ultrapure water, and then water remaining on the substrate and pattern is removed. After cleaning, it is preferable to remove the rinse liquid remaining on the substrate and the pattern.

[0096] By exposing a resist obtained using the negative resist composition of the present invention, it is possible to form a resist pattern with a highly accurate shape.

[0097] 4.Applications The negative resist composition of the present invention is useful for producing a thick resist film, for example, a resist film with a thickness of 1 to 50 μm. [Example]

[0098] The present invention will be explained in more detail with reference to examples. In the examples, "%" and "parts" representing the content or amount used are by mass unless otherwise specified. The weight average molecular weight is a value determined by gel permeation chromatography under the following conditions. Device: HLC-8320GPC model (Tosoh Corporation) Column: TSKgel Multipore H XL -M x 3 + guard column (Tosoh) Eluent: tetrahydrofuran Flow rate: 1.0mL / min Detector: RI detector Column temperature: 40℃ Injection volume: 100μl Molecular weight standard: Standard polystyrene (Tosoh Corporation)

[0099] Synthesis Example 1 [Synthesis of Resin (A2)-1] A four-neck flask equipped with a stirrer, reflux condenser, and thermometer was charged with 413.5 parts of 2,5-xylenol, 103.4 parts of salicylaldehyde, 20.1 parts of p-toluenesulfonic acid, and 826.9 parts of methanol. The mixture was heated to reflux and maintained at this temperature for 4 hours. After cooling, 1320 parts of methyl isobutyl ketone was added, and 1075 parts of the solvent was distilled off at normal pressure. 762.7 parts of m-cresol and 29.0 parts of 2-tert-butyl-5-methylphenol were added, and the mixture was heated to 65°C. 678 parts of 37% formalin was added dropwise over 1.5 hours, adjusting the temperature to 87°C at the end of the dropwise addition. The resulting mixture was maintained at 87°C for 10 hours, after which 1115 parts of methyl isobutyl ketone was added. The mixture was washed three times with deionized water. 500 parts of methyl isobutyl ketone was added to the resulting mixture, and the mixture was concentrated under reduced pressure until the total volume reached 3435 parts. To the resulting mixture, 3796 parts of methyl isobutyl ketone and 4990 parts of n-heptane were added, and the mixture was heated to 60°C and stirred for 1 hour. The mixture was then separated, and the lower layer containing the resin was removed, diluted with 3500 parts of propylene glycol monomethyl ether acetate, and concentrated to obtain 1690 parts of a propylene glycol monomethyl ether acetate solution of resin (A2)-1 (solid content 43%). The weight-average molecular weight of novolak resin (A2)-1 was 7 x 10 3 It was.

[0100] <Preparation of Negative Resist Composition> The components shown in Table 1 were mixed and dissolved to obtain a mixture, which was then filtered through a fluororesin filter with a pore size of 0.5 μm to prepare a negative resist composition.

[0101] [Table 1]

[0102] <Resin> (A1)-1: Resin (A1)-1 A resin containing the following structural units, synthesized by the method described in JP-A 2001-42529. TIFF2025181636000031.tif46170 Weight average molecular weight: 3700 The percentage of hydroxy groups in poly-p-hydroxystyrene replaced with ethoxy groups is 20.9%. (A2)-1: Resin (A2)-1 It was synthesized according to Synthesis Example 1. (A2)-2: Resin (A2)-2 A resin containing the following structural units, synthesized by the method described in JP-A 2001-42529. TIFF2025181636000032.tif31170 Weight average molecular weight: 9250

[0103] <Acid generator (B)> (B)-1: N-hydroxynaphthalimide triflate (Heraeus) TIFF2025181636000033.tif25170(B)-2: Synthesized by the method described in WO2014 / 084269 TIFF2025181636000034.tif27170(B)-3: Compound represented by the following formula (PAG-121; manufactured by BASF) TIFF2025181636000035.tif30170

[0104] <Crosslinking agent (E)> (E)-1: N,N,N,N,N,N-Hexakis(methoxymethyl)melamine (Tokyo Chemical Industry Co., Ltd.) TIFF2025181636000036.tif43170(E)-2: Compound represented by the following formula (manufactured by Heraeus) TIFF2025181636000037.tif32170

[0105] <Quencher (C)> (C)-1: 2,4,5-triphenylimidazole (Tokyo Chemical Industry Co., Ltd.)

[0106] <Solvent (D)> (D)-1: Propylene glycol monomethyl ether acetate

[0107] Examples 1 to 6, Comparative Examples 1 and 2 (i-line exposure evaluation of negative resist composition) The above negative resist composition was spin-coated onto a 4-inch silicon wafer substrate that had been treated with hexamethyldisilazane (HMDS) so that the film thickness after pre-baking would be 6 μm. Thereafter, the coating was pre-baked on a direct hot plate at 100° C. for 180 seconds to form a composition layer. Next, the composition layer formed on the wafer was exposed to light through a mask using an i-line stepper (NSR-2005i9C; manufactured by Nikon Corporation, NA=0.5) to form trench patterns (trench widths of 3, 2, and 1 μm) by gradually changing the exposure dose. After exposure, post-exposure baking was performed on a hot plate at 100° C. for 60 seconds, and then puddle development was performed with a 2.38 mass % aqueous solution of tetramethylammonium hydroxide for 180 seconds to obtain a resist pattern. The resist pattern obtained after development was observed under a scanning electron microscope, and the exposure dose at which a trench pattern with a width of 3 μm was obtained was taken as the effective sensitivity.

[0108] <Resolution evaluation> The resist pattern obtained at the effective sensitivity was observed with a scanning electron microscope, and the minimum line width of the resolved trench pattern was measured.

[0109] <Shape evaluation> The 3 μm trench patterns obtained at the effective sensitivity were observed under a scanning electron microscope, and were judged as follows: those with a good top and bottom shape close to a rectangle [Fig. 1(a)] were marked with a "○", those with a round top shape [Fig. 1(b)] or those with a notch at the bottom [Fig. 1(c)] were marked with a "△", and those with a round top shape [Fig. 1(b)] or those with a notch at the bottom [Fig. 1(c)] were marked with an "×". The results are shown in Table 2.

[0110] <Storage stability evaluation> The negative resist composition was stored at −5° C. for one month, and the state of the negative resist composition was visually observed. Those in which no solid precipitated were evaluated as “Good”, and those in which solid precipitated were evaluated as “Poor”.

[0111] [Table 2]

[0112] Examples 1 to 6 had good storage stability. Furthermore, Examples 1 to 6 also had good resolution and good shape. On the other hand, Comparative Example 1 had poor storage stability because only one type of acid generator ((B)-1) was used. Furthermore, Comparative Example 2 did not achieve resolution because only one type of acid generator ((B)-3) was used. [Industrial Applicability]

[0113] The negative resist composition of the present invention has good storage stability and is useful for semiconductor microfabrication.

Claims

1. A negative resist composition comprising a resin (A1), an acid generator (B), and a crosslinking agent (E), The resin (A1) contains a structural unit represented by formula (a2-1) and a structural unit represented by formula (a2-4), The acid generator (B) contains at least two types of acid generators each having a group represented by formula (B1), and at least one of the acid generators is a compound represented by formula (b1). A negative resist composition. [In formula (a2-1) and formula (a2-4), R ａ７ , and R ａ１３ each independently represents a hydrogen atom or a methyl group. R ａ１０ , and R ａ１４ each independently represents an alkyl group having 1 to 6 carbon atoms. R ａ１５ represents a hydrocarbon group having 1 to 12 carbon atoms. m １ represents an integer of 0 to 4. １ When is 2 or more, multiple R ａ１０ may be the same or different from each other. m ２ represents an integer of 1 to 4. However, m １ and m ２ The sum of these is 5 or less. m ３ represents an integer of 0 to 4. ３ When is 2 or more, multiple R ａ１４ may be the same or different from each other. m ４ represents an integer of 1 to 4. ４ When is 2 or more, multiple R ａ１５ may be the same or different from each other. However, m ３ and m ４ The sum of is 5 or less.] [In formula (B1), R ｂ１ represents a hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom, and a methylene group contained in the hydrocarbon group may be substituted with an oxygen atom or a carbonyl group. [In formula (b1), R ｂ１ represents the same meaning as above. R ｂ２ represents a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a thioalkyl group having 1 to 8 carbon atoms. Ring W ｂ１ represents an aromatic hydrocarbon ring having 6 to 14 carbon atoms or an aromatic heterocyclic ring having 6 to 14 carbon atoms. x represents an integer of 0 to 6. When x is 2 or more, a plurality of R ｂ２ may be the same or different.]

2. The acid generator (B) is (i) a combination of at least two compounds selected from compounds represented by formula (b1), or (ii) a combination of at least one compound selected from the compounds represented by formula (b1) and at least one compound selected from the compounds represented by formula (b2) and formula (b3); 2. The negative resist composition according to claim 1, comprising: [In formulas (b2) to (b3), R ｂ１ represents the same meaning as above. R ｂ３ and R ｂ４ each independently represents a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or a thioalkyl group having 1 to 8 carbon atoms.]

3. 2. The negative resist composition according to claim 1, wherein x is 1 in at least one compound selected from the group consisting of compounds represented by formula (b1) contained in the acid generator (B).

4. 2. The negative resist composition according to claim 1, further comprising a novolak resin.

5. 2. The negative resist composition according to claim 1, further comprising a quencher (C).

6. 2. A negative resist composition according to claim 1, wherein the crosslinking agent (E) is a melamine-based crosslinking agent or a glycoluril-based crosslinking agent.

7. A method for producing a resist pattern, comprising: (1) A step of applying the resist composition according to any one of claims 1 to 6 onto a substrate; (2) a step of drying the applied composition to form a composition layer; (3) exposing the composition layer to light; and (4) A step of heating and developing the composition layer after exposure A manufacturing method comprising:

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