Resist composition and pattern forming method

Abstract

The present invention relates to a resist composition and a pattern forming method. The subject of the present invention is to provide a resist composition that exhibits particularly good mask size dependence (mask error coefficient: MEF), LWR, and size uniformity (CDU) in optical lithography using high-energy rays such as ArF excimer laser as a light source, and to provide a pattern forming method using the resist composition. The solution to the problem is a resist composition, which is characterized by containing: (A) a resin containing repeating units with acid-labile groups and not containing repeating units with aromatic substituents, (B) a photoacid generator represented by the general formula (B‑1), and (C) a solvent. In the formula, W1 represents a cyclic divalent hydrocarbon group containing heteroatoms and having 4 to 12 carbon atoms. W2 represents a cyclic monovalent hydrocarbon group containing no heteroatoms and having 4 to 14 carbon atoms. Rf is a divalent organic group represented by the above general formula. M + represents an onium cation.

Description

Technical Field

[0001] The present invention relates to a resist composition and a pattern forming method. Background Art

[0002] With the high integration and high speed of LSI, miniaturization is also progressing rapidly. As for the most advanced miniaturization technology, mass production has been achieved by inserting liquid such as water between the projection lens and the substrate to perform exposure, and multiple exposure (multi-patterning) of ArF lithography and extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm are being studied.

[0003] Among the chemically amplified resist materials used in the above-mentioned photolithography, a compound that decomposes and generates an acid when exposed to light (hereinafter referred to as an "acid generator") is used. By optimizing the structure in the acid generator, acid diffusion can be suppressed and a high-resolution pattern can be formed. Such an acid generator has been studied, for example, those disclosed in Patent Documents 1 to 4.

[0004] Prior art literature

[0005] Patent Literature

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-074843

[0007] [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-191054

[0008] [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-126869

[0009] [Patent Document 4] Japanese Patent Application Laid-Open No. 2012-072108 Summary of the invention

[0010] Problem that the invention aims to solve

[0011] When miniaturization is further achieved, the acid generators that have been studied in the past are not necessarily sufficient in terms of many performance aspects, such as resolution and resist pattern shape.

[0012] The present invention is made to solve the above-mentioned problems, and an object of the present invention is to provide a resist composition and a pattern forming method that exhibit good mask size dependency (mask error factor: MEF), LWR, and size uniformity (CDU) in optical lithography.

[0013] Solutions for solving problems

[0014] In order to solve the above-mentioned problems, the present invention provides a resist composition, which is characterized by containing: (A) a resin containing a repeating unit having an acid-labile group and not containing a repeating unit having an aromatic substituent, (B) a photoacid generator represented by the general formula (B-1), and (C) a solvent.

[0015] [Chemistry 1]

[0016]

[0017] In the formula, W1 represents a cyclic divalent hydrocarbon group containing heteroatoms and having 4 to 12 carbon atoms. W2 represents a cyclic monovalent hydrocarbon group containing no heteroatoms and having 4 to 14 carbon atoms. Rf is a divalent organic group represented by the above general formula, A1 and A2 each independently represent a hydrogen atom or a trifluoromethyl group, B1 and B2 each independently represent a hydrogen atom, a fluorine atom or a trifluoromethyl group, and * represents an atomic bond with a carbonyloxy group. m represents 0 to 4, and n represents an integer from 0 to 1. M + represents an onium cation.

[0018] The resist composition of the present invention can exhibit good mask size dependency (mask error factor: MEF), LWR, and dimensional uniformity (CDU) in optical lithography.

[0019] In this case, W1 in the general formula (B-1) is preferably a cyclic divalent hydrocarbon group having 6 to 12 carbon atoms and containing a lactone ring structure.

[0020] According to such a resist composition, when acid is generated after exposure, the lactone ring is arranged near the sulfonic acid group, so that acid diffusion can be further suppressed, and thus better mask size dependency, LWR, and size uniformity can be exhibited.

[0021] In the general formula (B-1), W2 is preferably a polycyclic monovalent hydrocarbon group having 7 to 14 carbon atoms and containing no hetero atom.

[0022] According to such a resist composition, since a highly condensed hydrocarbon group is disposed at the terminal, appropriate solubility can be imparted, and thus better mask size dependency, LWR, and size uniformity can be exhibited.

[0023] Furthermore, the Rf group in the aforementioned general formula (B-1) is preferably selected from the groups represented by the following formulae (Rf-1) to (Rf-6).

[0024] [Chemistry 2]

[0025]

[0026] * represents an atomic bond to the oxycarbonyl group.

[0027] According to such a resist composition, the solubility is improved due to the effect of the fluorine atoms in Rf, and the sulfonic acid generated after exposure has an appropriate acid strength, so that better mask size dependency, LWR, and size uniformity can be exhibited.

[0028] The resist composition preferably further contains a component (D) which is a resin different from the resin of the component (A) and is a fluorine-containing resin having at least one repeating unit selected from the group consisting of the following formulae (D-1), (D-2) and (D-3).

[0029] [Chemistry 3]

[0030]

[0031] In the formula, R A are each independently a hydrogen atom or a methyl group. 51 and R 52 R is independently a hydrogen atom, or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms. 53 R is a single bond, or a linear or branched divalent hydrocarbon group having 1 to 5 carbon atoms. 54 , R 55 and R 56 R is independently a hydrogen atom, a linear, branched or cyclic monovalent hydrocarbon group having 1 to 15 carbon atoms, a fluorinated monovalent hydrocarbon group or an acyl group, or an acid-labile group. 54 , R 55 and R 56 When it is a monovalent hydrocarbon group or a fluorinated monovalent hydrocarbon group, part of their carbon atoms may be substituted by an ether group or a carbonyl group. 57 It is a linear, branched or cyclic hydrocarbon group or a fluorinated hydrocarbon group having a valence of (v+1) and a carbon number of 1 to 20. v is an integer of 1 to 3.

[0032] The resist composition of the present invention further contains such a component (D), which can improve the contact angle between the resist film surface and water, and suppress defects caused by residual wetting water or the dissolution of acid generators and quenchers. In addition, the solubility of the resist film surface can be adjusted to achieve good dimensional uniformity.

[0033] Furthermore, the present invention provides a pattern forming method, which is characterized by comprising the following steps: applying the above-mentioned resist composition on a substrate and performing a heat treatment to form a resist film, exposing the above-mentioned resist film to high-energy rays, and developing the exposed resist film using a developer.

[0034] Such a pattern forming method can achieve good mask size dependency, LWR, and size uniformity in optical lithography.

[0035] In the pattern forming method of the present invention, the high-energy ray may be an ArF excimer laser with a wavelength of 193 nm or a KrF excimer laser with a wavelength of 248 nm.

[0036] Furthermore, the aforementioned exposure may be an immersion exposure performed by inserting a liquid having a refractive index of 1.0 or higher between the resist film and the projection lens, or an immersion exposure may be performed by further forming a protective film on the aforementioned resist film and inserting the aforementioned liquid between the protective film and the projection lens to form a pattern.

[0037] Such a pattern forming method can form a pattern with better sensitivity and excellent MEF, LWR, and CDU.

[0038] Furthermore, in the pattern forming method of the present invention, the high-energy ray may be an electron beam or extreme ultraviolet ray having a wavelength of 3 to 15 nm.

[0039] In such a pattern forming method, good mask size dependency, LWR, and size uniformity can also be achieved.

[0040] Effects of the Invention

[0041] The resist composition of the present invention can form a resist pattern having excellent mask size dependency (mask error factor: MEF) and LWR.

[0042] The present invention can provide a resist composition and a pattern forming method that exhibit good mask size dependency (mask error factor: MEF), LWR, and size uniformity (CDU), particularly in optical lithography using ArF excimer laser as a light source.

[0043] Furthermore, the resist composition of the present invention has good sensitivity and good pattern shape, and is suitable as a material for ArF immersion lithography. In particular, it has good sensitivity and excellent MEF in both positive pattern formation by alkali development and negative pattern formation by organic solvent development, and is effective in various development processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] [ Figure 1 ] represents the PAG1 obtained in Example 1-1 1 Figure 1 HNMR spectrum.

[0045] [ Figure 2 ] represents the PAG1 obtained in Example 1-1 19 Figure 1. FNMR spectrum. DETAILED DESCRIPTION

[0046] As described above, when miniaturization is further achieved, the acid generators that have been studied in the past are not necessarily sufficient in terms of many performance aspects such as resolution and resist pattern shape.

[0047] The inventors of the present application have conducted in-depth studies to achieve the above-mentioned purpose and have obtained the following findings: a resist composition using an acid generator represented by the following formula (B-1) exhibits good MEF, LWR, and CDU and is extremely effective in precise microfabrication.

[0048] That is, the present invention provides a resist composition, characterized by comprising: (A) a resin containing repeating units having acid-labile groups and not containing repeating units having aromatic substituents, (B) a photoacid generator represented by the general formula (B-1), and (C) a solvent.

[0049] [Chemistry 4]

[0050]

[0051] In the formula, W1 represents a cyclic divalent hydrocarbon group containing heteroatoms and having 4 to 12 carbon atoms. W2 represents a cyclic monovalent hydrocarbon group containing no heteroatoms and having 4 to 14 carbon atoms. Rf is a divalent organic group represented by the above general formula, A1 and A2 each independently represent a hydrogen atom or a trifluoromethyl group, B1 and B2 each independently represent a hydrogen atom, a fluorine atom or a trifluoromethyl group, and * represents an atomic bond with a carbonyloxy group. m represents 0 to 4, and n represents an integer from 0 to 1. M + represents an onium cation.

[0052] The present invention is described in detail below, but the present invention is not limited thereto. In addition, in the following chemical formulas, enantiomers or diastereomers may often exist in the chemical structure, but unless otherwise specified, each chemical formula represents all of these stereoisomers in any case. Furthermore, these stereoisomers may be used alone or in the form of a mixture.

[0053] [Resist composition]

[0054] The resist composition of the present invention comprises: (A) a resin containing a repeating unit having an acid-labile group and not containing a repeating unit having an aromatic substituent, (B) a photoacid generator represented by the general formula (B-1), and (C) a solvent. It may further contain a specific fluorine-containing resin different from the resin of the component (A) as the component (D), or other components such as a quencher and a surfactant as needed. Each component is described below.

[0055] [(A) Base resin]

[0056] In the resist composition of the present invention, the base resin (resin A) of the component (A) is a resin containing a repeating unit having an acid-labile group and does not contain a repeating unit having an aromatic substituent other than the repeating unit containing an acid-labile group.

[0057] In the base resin of the component (A), examples of the repeating unit having an acid-labile group include the following general formula (a1).

[0058] [Chemistry 5]

[0059]

[0060] In the formula, R 1 is a hydrogen atom or a methyl group. X represents an acid-labile group.

[0061] The repeating unit represented by the general formula (a1) can provide a polymer that decomposes under the action of an acid to produce a carboxylic acid and becomes alkali-soluble. Various groups can be used as the acid-labile group X, specifically groups represented by the following general formulas (L1) to (L9), tertiary alkyl groups having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, trialkylsilyl groups having 1 to 6 carbon atoms, oxoalkyl groups having 4 to 20 carbon atoms, etc.

[0062] [Chemistry 6]

[0063]

[0064] Here, a dashed line represents an atomic bond (the same applies hereinafter).

[0065] In formula (L1), R L01 , R L02 represents a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and specific examples thereof include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, n-octyl, norbornyl, tricyclodecanyl, tetracyclododecyl, adamantyl and the like. L03 It represents a monovalent hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, which may have a hetero atom such as an oxygen atom, and includes linear, branched or cyclic alkyl groups, and groups in which a part of the hydrogen atoms is substituted with a hydroxyl group, an alkoxy group, an oxy group, an amino group, an alkylamino group, etc. Specific examples include the following substituted alkyl groups, etc.

[0066] [Chemistry 7]

[0067]

[0068] R L01 and R L02 , R L01 and R L03 , RL02 and R L03 They can also bond to each other and form a ring with the carbon atoms and oxygen atoms to which they are bonded. When a ring is formed, R L01 , R L02 , R L03 Each of them represents a linear or branched alkylene group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms.

[0069] In formula (L2), R L04 represents a tertiary alkyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, a trialkylsilyl group in which each alkyl group is a carbon atoms of 1 to 6 carbon atoms, an oxoalkyl group having 4 to 20 carbon atoms, or a group represented by the general formula (L1) above. As for the tertiary alkyl group, specific examples include: tert-butyl, tert-pentyl, 1,1-diethylpropyl, 2-cyclopentylpropane-2-yl, 2-cyclohexylpropane-2-yl, 2-(bicyclo[2.2.1]heptane-2-yl)propane-2-yl, 2-(adamantan-1-yl)propane-2-yl, 1-ethylcyclopentyl , 1-butylcyclopentyl, 1-ethylcyclohexyl, 1-butylcyclohexyl, 1-ethyl-2-cyclopentenyl, 1-ethyl-2-cyclohexenyl, 2-methyl-2-adamantyl, 2-ethyl-2-adamantyl, etc., as for the trialkylsilyl group, specifically, trimethylsilyl, triethylsilyl, dimethyl-tert-butylsilyl, etc., as for the oxoalkyl group, specifically, 3-oxocyclohexyl, 4-methyl-2-oxooxacyclohexane-4-yl, 5-methyl-2-oxooxacyclopentane-5-yl, etc., can be exemplified. l is an integer of 0 to 6.

[0070] In formula (L3), R L05 represents an optionally substituted linear, branched or cyclic alkyl group having 1 to 8 carbon atoms or an optionally substituted aryl group having 6 to 20 carbon atoms. Specific examples of the optionally substituted alkyl group include linear, branched or cyclic alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, cyclopentyl and cyclohexyl groups, and groups in which a part of the hydrogen atoms is substituted with hydroxyl, alkoxy, carboxyl, alkoxycarbonyl, oxy, amino, alkylamino, cyano, mercapto, alkylthio, sulfo and the like. Specific examples of the optionally substituted aryl group include phenyl, methylphenyl, naphthyl, anthracenyl, phenanthrenyl and pyrenyl groups. In formula (L3), m is 0 or 1, and n is any one of 0, 1, 2 and 3, and is a number satisfying 2m+n=2 or 3.

[0071] In formula (L4), R L06 represents an optionally substituted linear, branched or cyclic alkyl group having 1 to 8 carbon atoms or an optionally substituted aryl group having 6 to 20 carbon atoms, and specific examples thereof include and R L05 The same is true for others. L07 ~R L16Each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 15 carbon atoms, and specific examples thereof include: methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, and other linear, branched, or cyclic alkyl groups, and groups in which a portion of the hydrogen atoms is substituted with a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, an oxy group, an amino group, an alkylamino group, a cyano group, a mercapto group, an alkylthio group, a sulfo group, and the like. L07 ~R L16 They can also be bonded to form a ring (e.g. R L07 With R L08 , R L07 With R L09 , R L08 With R L10 , R L09 With R L10 , R L11 With R L12 , R L13 With R L14 In this case, it represents a divalent hydrocarbon group having 1 to 15 carbon atoms, and specifically, it can be exemplified by removing one hydrogen atom from the above-mentioned monovalent hydrocarbon groups. L07 ~R L16 The adjacent carbon atoms in the carbon atom can bond to each other without any other substance and form a double bond (for example, R L07 With R L09 , R L09 With R L15 , R L13 With R L15 wait).

[0072] In formula (L5), R L17 , R L18 , R L19 Each independently represents a linear, branched or cyclic alkyl group having 1 to 15 carbon atoms, and specific examples thereof include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, n-octyl, 1-adamantyl and 2-adamantyl.

[0073] In formula (L6), R L20 represents an optionally substituted linear, branched or cyclic alkyl group having 1 to 10 carbon atoms or an optionally substituted aryl group having 6 to 20 carbon atoms, and specific examples thereof include and R L05 The same and so on.

[0074] In formula (L7), R L21represents an optionally substituted linear, branched or cyclic alkyl group having 1 to 10 carbon atoms or an optionally substituted aryl group having 6 to 20 carbon atoms, and specific examples thereof include and R L05 The same and so on.

[0075] R L24 represents a divalent group which forms a substituted or unsubstituted cyclopentane ring, cyclohexane ring or norbornane ring together with the carbon atom to which it is bonded. L22 , R L23 R each independently represents a hydrogen atom or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms. L22 and R L23 They may be bonded to each other and form a ring together with the carbon atoms to which they are bonded, in which case they represent a divalent group forming a substituted or unsubstituted cyclopentane ring or cyclohexane ring. p represents 1 or 2.

[0076] In formula (L8), R L25 represents an optionally substituted linear, branched or cyclic alkyl group having 1 to 10 carbon atoms or an optionally substituted aryl group having 6 to 20 carbon atoms, and specific examples thereof include and R L05 The same and so on.

[0077] R L28 represents a divalent group which forms a substituted or unsubstituted cyclopentane ring, cyclohexane ring or norbornane ring together with the carbon atom to which it is bonded. L26 , R L27 R each independently represents a hydrogen atom or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms. L26 and R L27 They may be bonded to each other and form a ring together with the carbon atoms to which they are bonded, in which case they represent a divalent group forming a substituted or unsubstituted cyclopentane ring or cyclohexane ring. q represents 1 or 2.

[0078] In formula (L9), R L29 represents an optionally substituted linear, branched or cyclic alkyl group having 1 to 10 carbon atoms or an optionally substituted aryl group having 6 to 20 carbon atoms, and specific examples thereof include and R L05 The same and so on.

[0079] R L32 represents a divalent group which forms a substituted or unsubstituted cyclopentane ring, cyclohexane ring or norbornane ring together with the carbon atom to which it is bonded. L30 , R L31 R each independently represents a hydrogen atom or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms. L30 and R L31 They may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, and in this case, they represent a divalent group forming a substituted or unsubstituted cyclopentane ring or cyclohexane ring.

[0080] Among the acid-labile groups represented by the above formula (L1), specific examples of linear or branched acid-labile groups include the following groups.

[0081] [Chemistry 8]

[0082]

[0083] Among the acid-labile groups represented by the formula (L1), specific examples of cyclic groups include tetrahydrofuran-2-yl, 2-methyltetrahydrofuran-2-yl, tetrahydropyran-2-yl, and 2-methyltetrahydropyran-2-yl.

[0084] Specific examples of the acid-labile group of the above formula (L2) include: tert-butoxycarbonyl, tert-butoxycarbonylmethyl, tert-pentyloxycarbonyl, tert-pentyloxycarbonylmethyl, 1,1-diethylpropyloxycarbonyl, 1,1-diethylpropyloxycarbonylmethyl, 1-ethylcyclopentyloxycarbonyl, 1-ethylcyclopentyloxycarbonylmethyl, 1-ethyl-2-cyclopentenyloxycarbonyl, 1-ethyl-2-cyclopentenyloxycarbonylmethyl, 1-ethoxyethoxycarbonylmethyl, 2-tetrahydropyranyloxycarbonylmethyl, 2-tetrahydrofuranyloxycarbonylmethyl, and the like.

[0085] Specific examples of the acid-labile group of the above formula (L3) include: 1-methylcyclopentyl, 1-ethylcyclopentyl, 1-n-propylcyclopentyl, 1-isopropylcyclopentyl, 1-n-butylcyclopentyl, 1-sec-butylcyclopentyl, 1-tert-butylcyclopentyl, 1-cyclohexylcyclopentyl, 1-(4-methoxy-n-butyl)cyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl, 3-methyl-1-cyclopenten-3-yl, 3-ethyl-1-cyclopenten-3-yl, 3-methyl-1-cyclohexen-3-yl, 3-ethyl-1-cyclohexen-3-yl, etc.

[0086] The acid-labile group of the above formula (L4) is particularly preferably a group represented by the following formulas (L4-1) to (L4-4).

[0087] [Chemistry 9]

[0088]

[0089] In the above general formulae (L4-1) to (L4-4), the dashed lines indicate the bonding position and bonding direction. L41 Each independently represents a monovalent hydrocarbon group such as a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and specific examples thereof include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, cyclopentyl and cyclohexyl.

[0090] In the aforementioned general formulae (L4-1) to (L4-4), enantiomers and diastereomers may exist, and the aforementioned general formulae (L4-1) to (L4-4) represent all of these stereoisomers. These stereoisomers may be used alone or in the form of a mixture.

[0091] For example, the general formula (L4-3) represents one or a mixture of two groups selected from the groups represented by the following general formulas (L4-3-1) and (L4-3-2).

[0092] [Chemistry 10]

[0093]

[0094] The general formula (L4-4) represents one or a mixture of two or more selected from the groups represented by the following general formulae (L4-4-1) to (L4-4-4).

[0095] [Chemistry 11]

[0096]

[0097] The above general formulae (L4-1) to (L4-4), (L4-3-1), (L4-3-2) and (L4-4-1) to (L4-4-4) also represent their mirror image isomers and mixtures of mirror image isomers.

[0098] In addition, by making the bonding direction of (L4-1) to (L4-4), (L4-3-1), (L4-3-2) and (L4-4-1) to (L4-4-4) respectively outward (exo) relative to the bicyclo [2.2.1] heptane ring, high reactivity in the acid catalyst removal reaction can be achieved (refer to Japanese Patent Publication No. 2000-336121). When producing these monomers with tertiary exo-alkyl groups having a bicyclo [2.2.1] heptane skeleton as substituents, there are sometimes cases where monomers containing endo alkyl groups represented by the following general formula (L4-1-endo) to (L4-4-endo) are contained. In order to achieve good reactivity, the exo ratio is preferably 50% or more, and the exo ratio is more preferably 80% or more.

[0099] [Chemistry 12]

[0100]

[0101] In the formula, R 13 Representation and illustration as R L41 The same group.

[0102] Refer to Japanese Patent Application Laid-Open No. 2000-336121.

[0103] Specific examples of the acid-labile group in the formula (L4) include the following groups.

[0104] [Chemistry 13]

[0105]

[0106] In addition, the tertiary alkyl group having 4 to 20 carbon atoms, the alkyl groups each having 1 to 6 carbon atoms, the oxoalkyl group having 4 to 20 carbon atoms, and R L04 The same as those listed above, etc.

[0107] Specific examples of the acid-labile group of the formula (L5) include a tert-butyl group, a tert-amyl group, and the following groups.

[0108] [Chemistry 14]

[0109]

[0110] Specific examples of the acid-labile group in the formula (L6) include the following groups.

[0111] [Chemistry 15]

[0112]

[0113] Specific examples of the acid-labile group in the formula (L7) include the following groups.

[0114] [Chemistry 16]

[0115]

[0116] Specific examples of the acid-labile group in the formula (L8) include the following groups.

[0117] [Chemistry 17]

[0118]

[0119] Specific examples of the acid-labile group in the formula (L9) include the following groups.

[0120] [Chemistry 18]

[0121]

[0122] Specific examples of the monomer represented by the general formula (a1) include the following, but are not limited thereto.

[0123] [Chemistry 19]

[0124]

[0125] In the formula, R 1 represents a hydrogen atom or a methyl group.

[0126] [Chemistry 20]

[0127]

[0128] In the formula, R 1 represents a hydrogen atom or a methyl group.

[0129] [Chemistry 21]

[0130]

[0131] In the formula, R 1 represents a hydrogen atom or a methyl group.

[0132] [Chemistry 22]

[0133]

[0134] In the formula, R 1 represents a hydrogen atom or a methyl group.

[0135] Furthermore, in the base resin of the component (A), in addition to the unit represented by the above-mentioned general formula (a1), monomers represented by the following general formulae (a2) to (a4) may be used as needed.

[0136] [Chemistry 23]

[0137]

[0138] In the formula, R 1 Same as above. 5 and R 6 Each independently represents a hydrogen atom or a hydroxyl group. Y represents a substituent having a lactone structure or a substituent having a sultone structure. Z represents a hydrogen atom, or a substituent of a fluorinated hydrocarbon group having 1 to 15 carbon atoms or a fluorinated alcohol group having 1 to 15 carbon atoms.

[0139] The unit represented by the general formula (a2) may be specifically exemplified by the following, but is not limited thereto.

[0140] [Chemistry 24]

[0141]

[0142] Specific examples of the monomer represented by the general formula (a3) ​​include the following, but are not limited thereto.

[0143] [Chemistry 25]

[0144]

[0145] In the formula, R 1represents a hydrogen atom or a methyl group.

[0146] [Chemistry 26]

[0147]

[0148] In the formula, R 1 represents a hydrogen atom or a methyl group.

[0149] [Chemistry 27]

[0150]

[0151] In the formula, R 1 represents a hydrogen atom or a methyl group.

[0152] [Chemistry 28]

[0153]

[0154] In the formula, R 1 represents a hydrogen atom or a methyl group.

[0155] Specific examples of the repeating unit represented by the general formula (a4) include the following, but are not limited thereto.

[0156] [Chemistry 29]

[0157]

[0158] Monomers having carbon-carbon double bonds other than those mentioned above may also be used in the resist composition of the present invention, for example: substituted acrylates such as methyl methacrylate, methyl crotonate, dimethyl maleate, dimethyl itaconic acid; unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid; norbornene, norbornene derivatives, tetracyclo[4.4.0.1 2,5 .17 7,10 ] Cyclic olefins such as dodecene derivatives; unsaturated acid anhydrides such as itaconic anhydride, α-methylene-γ-butyrolactones, α-methylstyrenes, and other monomers.

[0159] The weight average molecular weight (Mw) of resin A (base resin of component (A)) is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. Within the above range, there is no concern that etching resistance is reduced or that the contrast before and after exposure cannot be ensured and the resolution is reduced. In the present invention, Mw is a polystyrene-converted measurement value obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[0160] In addition, when the molecular weight distribution (Mw / Mn) of resin A is wide, both low molecular weight and high molecular weight polymers exist, so there is a concern that foreign matter may be observed on the pattern after exposure, or the pattern shape may deteriorate. Therefore, since the influence of such molecular weight and molecular weight distribution tends to become larger as the pattern rules become finer, in order to obtain a resist composition suitable for fine pattern sizes, the molecular weight distribution of resin A is preferably 1.0 to 2.0, and a narrow distribution of 1.0 to 1.5 is particularly preferred.

[0161] The method for synthesizing resin A includes, for example, a method in which a monomer having an unsaturated bond for obtaining a repeating unit represented by formula (a1) and a repeating unit represented by formulas (a2) to (a4) or other repeating units as required is placed in an organic solvent, and a free radical initiator is added to carry out thermal polymerization. Examples of the organic solvent used in the polymerization include: toluene, benzene, THF, diethyl ether, dioxane, methyl ethyl ketone, γ-butyrolactone, propylene glycol monomethyl ether acetate (PGMEA), etc. Examples of polymerization initiators include: 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylpropionic acid) dimethyl ester, benzoyl peroxide, lauroyl peroxide, etc. The reaction temperature is preferably 50 to 150°C, and more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours. The acid-labile group may be directly introduced into the monomer, or may be protected or partially protected after polymerization. In addition, in order to adjust the molecular weight, a known chain transfer agent such as dodecyl mercaptan or 2-mercaptoethanol may be used to carry out polymerization. In this case, the amount of the chain transfer agent added is preferably an amount of 0.01 to 10 expressed in molar ratio relative to the total monomers to be polymerized.

[0162] In the resin A, the preferred content ratio of each repeating unit derived from each monomer can be set to, for example, the range shown below, but is not limited thereto.

[0163] The repeating unit represented by formula (I) (a1) preferably contains 1 to 99 mol %, more preferably 20 to 95 mol %, and even more preferably 30 to 90 mol %.

[0164] (II) at least one type selected from the repeating units represented by formulae (a2) to (a4) is preferably contained in an amount of 0 to 99 mol %, more preferably 1 to 90 mol %, and even more preferably 10 to 70 mol %,

[0165] (III) The content of other repeating units is preferably 0 to 99 mol %, more preferably 0 to 70 mol %, and even more preferably 0 to 50 mol %.

[0166] In addition, the base resin of component (A) may contain two or more resins having different composition ratios, molecular weights or molecular weight distributions, and may contain a resin not containing a repeating unit represented by formula (a1) in addition to a resin having a repeating unit having an acid-labile group as needed.

[0167] [(B) Photoacid generator]

[0168] The resist composition of the present invention contains a photoacid generator represented by the following formula (B-1) as the component (B).

[0169] [Chemistry 30]

[0170]

[0171] In the formula, W1 represents a cyclic divalent hydrocarbon group containing heteroatoms and having 4 to 12 carbon atoms. W2 represents a cyclic monovalent hydrocarbon group containing no heteroatoms and having 4 to 14 carbon atoms. Rf is a divalent organic group represented by the above general formula, A1 and A2 each independently represent a hydrogen atom or a trifluoromethyl group, B1 and B2 each independently represent a hydrogen atom, a fluorine atom or a trifluoromethyl group, and * represents an atomic bond with a carbonyloxy group. m represents 0 to 4, and n represents an integer from 0 to 1. M + represents an onium cation.

[0172] Specific examples of the heteroatom-containing cyclic divalent hydrocarbon group having 4 to 12 carbon atoms represented by W1 include the following.

[0173] [Chemistry 31]

[0174]

[0175] * represents an atomic bond to the oxycarbonyl group.

[0176] Particularly preferred W1 includes cyclic divalent hydrocarbon groups containing a lactone ring structure, and particularly preferred are cyclic divalent hydrocarbon groups containing a lactone ring structure having a carbon number of 6 to 12. When acid is generated after exposure, the lactone ring is arranged near the sulfonic acid group to further suppress acid diffusion.

[0177] Specific examples of the heteroatom-free cyclic monovalent hydrocarbon group having 4 to 14 carbon atoms represented by W2 include the following.

[0178] [Chemistry 32]

[0179]

[0180] Dashed lines represent atomic bonds.

[0181] W2 is preferably a polycyclic monovalent hydrocarbon group containing no heteroatoms and having 7 to 14 carbon atoms. A particularly preferred W2 is an adamantyl group. By arranging a highly condensed hydrocarbon group at the terminal, appropriate solubility can be imparted.

[0182] Rf is a divalent organic group represented by the above general formula. Here, A1 and A2 each independently represent a hydrogen atom or a trifluoromethyl group, B1 and B2 each independently represent a hydrogen atom, a fluorine atom or a trifluoromethyl group, and * represents an atomic bond with a carbonyloxy group. m represents 0 to 4, and n represents an integer of 0 to 1. Preferably, m+n>0.

[0183] The Rf group is particularly preferably selected from the groups represented by the following formulae (Rf-1) to (Rf-6).

[0184] [Chemistry 33]

[0185]

[0186] * represents an atomic bond to the carbonyloxy group.

[0187] If the photoacid generator represented by formula (B-1) has such an Rf, the solubility is improved due to the effect of the fluorine atom, and the sulfonic acid generated after exposure has an appropriate acid strength, which is preferred.

[0188] Specific examples of the structure of the anion part of the photoacid generator represented by formula (B-1) are shown below, but the invention is not limited thereto.

[0189] [Chemistry 34]

[0190]

[0191] [Chemistry 35]

[0192]

[0193] [Chemistry 36]

[0194]

[0195] In formula (B-1), M + The onium cation represented is preferably at least one selected from the group consisting of cations represented by the following formula (b1) and formula (b2).

[0196] [Chemistry 37]

[0197]

[0198] In formula (b1) and (b2), R 41 ~R 45 are each independently a linear, branched or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 41 , R 42 and R 43 Any two of them may be bonded to each other and form a ring together with the sulfur atom in the formula.

[0199] R 41 ~R 45 The monovalent hydrocarbon groups represented by include: alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups such as vinyl, allyl, propenyl, butenyl, hexenyl, and cyclohexenyl; aryl groups such as phenyl, naphthyl, and thienyl; aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl. Among them, aryl groups are preferred. In addition, the hydrogen atoms of a part of the above-mentioned monovalent hydrocarbon groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and the carbon atoms of a part of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, hydroxyl groups, cyano groups, carbonyl groups, ether groups, ester groups, sulfonate groups, carbonate groups, lactone rings, sultone rings, carboxylic anhydrides, and halogenated alkyl groups may also be contained.

[0200] Examples of the sulfonium cation represented by the formula (b1) include, but are not limited to, the following.

[0201] [Chemistry 38]

[0202]

[0203] [Chemistry 39]

[0204]

[0205] [Chemistry 40]

[0206]

[0207] [Chemistry 41]

[0208]

[0209] [Chemistry 42]

[0210]

[0211] [Chemistry 43]

[0212]

[0213] [Chemistry 44]

[0214]

[0215] [Chemistry 45]

[0216]

[0217] Examples of the iodonium cation represented by the formula (b2) include, but are not limited to, the following.

[0218] [Chemistry 46]

[0219]

[0220] Furthermore, in order to fine-tune the photolithography performance, the resist composition of the present invention may also contain other photoacid generators other than the aforementioned photoacid generators. As for other photoacid generators, if they are compounds that generate acid due to high-energy radiation irradiation, they may be any, and any known resist composition, especially a well-known one used in a chemically amplified resist composition, may be sufficient. As for other ideal photoacid generators, there are sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc., which can be used alone or in combination of two or more. As for the acid generated from other photoacid generators, it is preferable to be a strong acid such as sulfonic acid, (bisperfluoroalkanesulfonyl)imide, (trisperfluoromethanesulfonyl)methide, or a weak acid such as carboxylic acid.

[0221] Specific examples of other photoacid generators include the following formulas (B-2), (B-3), and (B-4).

[0222] [Chemistry 47]

[0223]

[0224] In formula (B-2), A 1 is a hydrogen atom or a trifluoromethyl group. 21 It is a linear, branched or cyclic monovalent hydrocarbon group having 1 to 35 carbon atoms which may contain an oxygen atom, a nitrogen-containing heterocyclic group or a group represented by the following formula (i). + It is an onium cation.

[0225] [Chemistry 48]

[0226]

[0227] In formula (i), R 31 and R 32 Each of R is independently a hydrogen atom or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 31 and R 32 They may also bond to each other and to the nitrogen atom to which they are bonded to form a ring. 33 It is a linear, branched or cyclic divalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom.

[0228] R 21The monovalent hydrocarbon group which may contain an oxygen atom represented by the present invention may include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, 1-adamantyl, and 1-adamantylmethyl; groups containing a steroid structure; 2-oxocyclopentyl, 2-oxocyclohexyl, 4-oxocyclohexyl, 2-oxopropyl, 2-oxoethyl, 2-cyclopentyl-2-oxoethyl, 2-cyclohexyl-2-oxoethyl, 2-(4-methylcyclohexyl)-2-oxoethyl, 4-oxa-tricyclo[4.2.1.0 3,7 ] oxoalkyl such as nonan-5-on-9-yl, 4-oxo-1-adamantyl; phenyl, 1-naphthyl, 2-naphthyl, anthracenyl, thienyl, 4-hydroxyphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 4-tert-butoxyphenyl, 3-tert-butoxyphenyl and other alkoxyphenyls; 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 4-n-butylphenyl, 2,4-dimethylphenyl, etc. Alkyl naphthyl such as alkylphenyl, methyl naphthyl, ethyl naphthyl, alkoxy naphthyl such as methoxy naphthyl, ethoxy naphthyl, dialkyl naphthyl such as dimethyl naphthyl, diethyl naphthyl, dialkoxy naphthyl such as dimethoxy naphthyl, diethoxy naphthyl, etc.; aryl groups such as benzyl, 1-phenylethyl, 2-phenylethyl, etc.; aryl oxyalkyl groups such as 2-aryl-2-oxoethyl such as 2-phenyl-2-oxoethyl, 2-(1-naphthyl)-2-oxoethyl, 2-(2-naphthyl)-2-oxoethyl, etc. Other examples include vinyl, isopropenyl, etc.

[0229] R 21 Examples of the nitrogen-containing heterocyclic group represented by include aziridine, pyrrolidine, piperidine, morpholine, pyrrole, pyridine, azetine, oxazole, isoxazole, thiazole, isothiazole, imidazole, pyrazole, pyridazine, pyrimidine, pyrazine, pyrroline, 2-imidazoline, imidazolidine, 3-pyrazoline, pyrazolidine, piperazine, triazine, oxadiazine, dithiazine, indole, isoindole, quinoline, isoquinoline, cinnoline, phthalazine, quinazoline, quinoxaline, 1,8-naphthyridine, purine, pteridine, indolizine, carbazole, acridine, phenazine, phenanthridine, 1,10-phenanthroline, phenoxazine, indoline, isoindoline, quinuclidine, benzo[e]indole, benzo[cd]indole, and the like.

[0230] As R 21 Particularly preferred ones include tert-butyl, cyclohexyl, 1-adamantyl, 1-adamantylmethyl, 4-oxa-tricyclo[4.2.1.0 3,7 ]nonan-5-one-9-yl, 4-oxo-1-adamantyl, alkyl groups containing a steroid structure, and the like.

[0231] In formula (i), R31 and R 32 The monovalent hydrocarbon group represented by ] can be exemplified by alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups such as vinyl, allyl, propenyl, butenyl, hexenyl, and cyclohexenyl; aryl groups such as phenyl, naphthyl, and thienyl; and aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl. In addition, in the aforementioned hydrocarbon group, part of the hydrogen atoms thereof may be substituted by the aforementioned monovalent hydrocarbon group, or a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms, or part of the carbon atoms of these groups may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms, and as a result, a hydroxyl group, a cyano group, a carbonyl group, an ether group, an ester group, a sulfonate group, a carbonate group, a lactone ring, a sultone ring, a carboxylic anhydride, a haloalkyl group, or the like may be contained.

[0232] R 31 and R 32 When they are bonded to each other and to form a ring together with the nitrogen atom to which they are bonded, specific ring types include aziridine, pyrrolidine, piperidine, morpholine, pyrrole, pyridine, azetidine, oxazole, isoxazole, thiazole, isothiazole, imidazole, pyrazole, pyridazine, pyrimidine, pyrazine, pyrroline, 2-imidazoline, imidazolidine, 3-pyrazoline, pyrazolidine, piperazine, triazine, oxadiazine, dithiazine, indole, isoindole, quinoline, isoquinoline, cinnoline, phthalazine, quinazoline, quinoxaline, 1,8-naphthyridine, purine, pteridine, indolizine, carbazole, acridine, phenazine, phenanthridine, 1,10-phenanthroline, phenoxazine, indoline, isoindoline, quinuclidine, benzo[e]indole, benzo[cd]indole, and the like. Furthermore, the hydrogen atoms of some of these rings may be replaced by the aforementioned hydrocarbon groups, or groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, or the carbon atoms of some of these rings may be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, hydroxyl groups, cyano groups, carbonyl groups, ether groups, ester groups, sulfonate groups, carbonate groups, lactone rings, sultone rings, carboxylic anhydrides, haloalkyl groups, and the like may be contained.

[0233] In formula (i), R 33The divalent hydrocarbon group represented by the present invention includes methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, -diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, heptadecan-1,17-diyl and other straight-chain alkanediyl groups; branched alkanediyl groups formed by adding side chains such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl and the like to the above-mentioned straight-chain alkanediyl groups; saturated cyclic hydrocarbon groups such as cyclopentanediyl, cyclohexanediyl, norbornanediyl, adamantanediyl and the like; unsaturated cyclic divalent hydrocarbon groups such as phenylene and naphthylene. In addition, some of the hydrogen atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms and halogen atoms, or some of the carbon atoms of these groups may be inserted with groups containing heteroatoms such as oxygen atoms, sulfur atoms and nitrogen atoms, and as a result, hydroxyl groups, cyano groups, carbonyl groups, ether groups, ester groups, sulfonate groups, carbonate groups, lactone rings, sultone rings, carboxylic anhydrides, alkyl halides and the like may be contained.

[0234] The specific examples of the structure of the anion part of the photoacid generator represented by formula (B-2) are shown below, but are not limited thereto. 1 Same as above.

[0235] [Chemistry 49]

[0236]

[0237] [Chemistry 50]

[0238]

[0239] In formula (B-2), M + The onium cation represented by is preferably at least one selected from the cations represented by the above formula (b1) and formula (b2).

[0240] In formula (B-3), A 2 is a hydrogen atom or a trifluoromethyl group. 22 , R 23 and R 24 Each is independently a hydrogen atom, or a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. p and q are each independently an integer of 0 to 5. r is an integer of 0 to 4. L is a single bond, an ether group, or a linear, branched, or cyclic divalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom.

[0241] R 22 , R23 and R 24 The monovalent hydrocarbon group represented by the present invention includes methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6 ] alkyl groups such as decyl and adamantyl. In addition, some of the hydrogen atoms in these groups may be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, or some of the carbon atoms in these groups may be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in hydroxyl groups, cyano groups, carbonyl groups, ether groups, ester groups, sulfonate groups, carbonate groups, lactone rings, sultone rings, carboxylic anhydride, haloalkyl groups, etc. R 22 , R 23 and R 24 Preferred are methyl, methoxy, tert-butyl, tert-butoxy and the like.

[0242] In the formula (B-3), the divalent hydrocarbon group represented by L can be exemplified as R 33 In addition, it can be a combination of two or more of these groups. In addition, the hydrogen atoms of some of these groups can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, or the carbon atoms of some of these groups can be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, hydroxyl groups, cyano groups, carbonyl groups, ether groups, ester groups, sulfonate groups, carbonate groups, lactone rings, sultone rings, carboxylic anhydrides, halogenated alkyl groups, etc. can be contained.

[0243] The photoacid generator represented by formula (B-3) may be exemplified by the following, but is not limited thereto. 2 Same as above.

[0244] [Chemistry 51]

[0245]

[0246] [Chemistry 52]

[0247]

[0248] (B) The photoacid generator may further include a compound represented by the above formula (B-4). 3 and A 4 are independently a hydrogen atom or a trifluoromethyl group, and cannot be a hydrogen atom at the same time. 25M is a linear, branched or cyclic monovalent hydrocarbon group having 1 to 35 carbon atoms which may contain an oxygen atom, a nitrogen-containing heterocyclic group or a group represented by the above formula (i). + The same as the above-mentioned onium cation.

[0249] Specific examples of the structure of the anion part of the photoacid generator represented by formula (B-4) are shown below, but the invention is not limited thereto.

[0250] [Chemistry 53]

[0251]

[0252] [Chemistry 54]

[0253]

[0254] Among the above-mentioned other photoacid generators, compounds having a fluorine-containing structure represented by a trifluoromethyl group as an anion structure have high hydrophobicity and less dissolution in immersion water. In addition, due to the fluorine-containing structure, the solvent solubility is high, and when developing with an organic solvent, the residue after development can be reduced. This can reduce defects after development, and is suitable as a resist composition for ArF immersion exposure.

[0255] Specific examples other than the above-mentioned photoacid generator include, for example, compounds described in paragraphs

[0122] to

[0142] of Japanese Patent Application Laid-Open No. 2008-111103, and particularly preferred compounds include compounds described in paragraphs

[0088] to

[0092] of Japanese Patent Application Laid-Open No. 2014-001259, compounds described in paragraphs

[0015] to

[0017] of Japanese Patent Application Laid-Open No. 2012-41320, and compounds described in paragraphs

[0015] to

[0029] of Japanese Patent Application Laid-Open No. 2012-106986. The partially fluorinated sulfonic acid generating type photoacid generator described in the above-mentioned publications can be preferably used, especially in ArF lithography, because the strength and diffusion distance of the acid generated are appropriate.

[0256] The content of the photoacid generator of component (B) is preferably 0.1 to 50 parts by mass, more preferably 0.2 to 40 parts by mass, and even more preferably 0.3 to 35 parts by mass relative to 100 parts by mass of the base resin of component (A). If it is within the above range, the resolution will not deteriorate, and there will be no concern about the generation of foreign matter after the development of the resist film or during the peeling. In addition, the content of the compound represented by formula (B-4) when added is preferably 0 to 50% by mass in the photoacid generator of component (B).

[0257] [(C) Solvent]

[0258] The resist composition of the present invention contains a solvent as the component (C). Examples of the solvent include ketones such as cyclohexanone and methyl-2-n-pentyl ketone described in paragraphs

[0144] to

[0145] of JP-A-2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; lactones such as γ-butyrolactone and ketoalcohols such as diacetone alcohol; and mixed solvents thereof. When an acetal acid-labile group is used, a high-boiling alcohol solvent may be added to accelerate the deprotection reaction of the acetal. Specifically, diethylene glycol, propylene glycol, glycerol, 1,4-butanediol, 1,3-butanediol, etc. may be added.

[0259] The content of the solvent of the component (C) is preferably 100 to 10,000 parts by mass, more preferably 300 to 8,000 parts by mass, based on 100 parts by mass of the base resin of the component (A).

[0260] [(D) Fluorine-containing resin]

[0261] The resist composition of the present invention may contain a resin different from the resin A, and may contain at least one fluorine-containing resin selected from the repeating units represented by the following formulae (D-1), (D-2) and (D-3).

[0262] [Chemistry 55]

[0263]

[0264] In the formula, R A is a hydrogen atom or a methyl group. 51 and R 52 R is independently a hydrogen atom, or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms. 53 R is a single bond, or a linear or branched divalent hydrocarbon group having 1 to 5 carbon atoms. 54 , R 55 and R 56 R is independently a hydrogen atom, a linear, branched or cyclic monovalent hydrocarbon group having 1 to 15 carbon atoms, a fluorinated monovalent hydrocarbon group or an acyl group, or an acid-labile group. 54 , R 55 and R 56 When it is a monovalent hydrocarbon group or a fluorinated monovalent hydrocarbon group, part of their carbon atoms may be substituted by an ether group or a carbonyl group. 57It is a linear, branched or cyclic hydrocarbon group or a fluorinated hydrocarbon group having a valence of (v+1) and a carbon number of 1 to 20. v is an integer of 1 to 3.

[0265] R 51 and R 52 Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, adamantyl, and norbornyl. Among them, a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 6 carbon atoms is preferred.

[0266] R 53 Specific examples of the divalent hydrocarbon group having 1 to 5 carbon atoms represented by include a methylene group, an ethylene group, a trimethylene group, a propylene group, a tetramethylene group, a pentamethylene group, and the like.

[0267] R 54 , R 55 and R 56 The monovalent hydrocarbon group having 1 to 15 carbon atoms represented by the alkyl group may be alkyl, alkenyl, alkynyl, etc., preferably alkyl. The aforementioned alkyl group may be exemplified by the aforementioned ones, and may also be exemplified by n-undecyl, n-dodecyl, tridecyl, tetradecyl, pentadecyl, etc. The aforementioned fluorinated monovalent hydrocarbon group having 1 to 15 carbon atoms may be exemplified by groups in which some or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned monovalent hydrocarbon group are substituted by fluorine atoms. As mentioned above, some of their carbon atoms may be substituted by ether groups or carbonyl groups.

[0268] R 54 , R 55 and R 56 When it is an acid-labile group, specific examples thereof include: groups represented by the aforementioned formulae (L1) to (L9), tertiary alkyl groups having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, trialkylsilyl groups in which each alkyl group is an alkyl group having 1 to 6 carbon atoms, oxoalkyl groups having 4 to 20 carbon atoms, etc.

[0269] R 57 Examples of the (v+1)-valent hydrocarbon group or fluorinated hydrocarbon group having 1 to 20 carbon atoms include groups obtained by removing a necessary number of hydrogen atoms from the above-mentioned monovalent hydrocarbon group or fluorinated monovalent hydrocarbon group.

[0270] The repeating units represented by formula (D-1) include, but are not limited to, the following. A Same as above.

[0271] [Chemistry 56]

[0272]

[0273] The repeating units represented by formula (D-2) include, but are not limited to, the following. A Same as above.

[0274] [Chemistry 57]

[0275]

[0276] The repeating units represented by formula (D-3) include, but are not limited to, the following. A Same as above.

[0277] [Chemistry 58]

[0278]

[0279] The Mw of the fluorine-containing resin of the component (D) is preferably 1,000 to 100,000, more preferably 3,000 to 15,000. The Mw / Mn is preferably 1.0 to 2.0, more preferably 1.0 to 1.6.

[0280] When synthesizing the fluorine-containing resin of component (D), one method thereof is to add a free radical initiator to an organic solvent to obtain a monomer having an unsaturated bond for obtaining repeating units represented by formulas (D-1) to (D-3) and other repeating units as required, and to carry out heat polymerization. Examples of the organic solvent used in the polymerization include toluene, benzene, THF, diethyl ether, dioxane, methyl ethyl ketone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc. Examples of the polymerization initiator include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylpropionic acid) dimethyl ester, benzoyl peroxide, lauroyl peroxide, etc. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. The acid-labile group may be used directly by introducing it into the monomer, or it may be protected or partially protected after polymerization. In order to adjust the molecular weight, the polymerization may be carried out using a known chain transfer agent such as dodecyl mercaptan or 2-mercaptoethanol. In this case, the amount of the chain transfer agent added is preferably 0.01 to 10 in terms of molar ratio relative to all monomers to be polymerized.

[0281] When the resist composition of the present invention contains a fluorine-containing resin as component (D), its content is preferably 0.1 to 50 parts by mass, and more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the base resin of component (A). If the content is within the above range, the contact angle between the surface of the resist film and water can be fully improved, and defects caused by residual wetting water, or the dissolution of acid generators and quenchers can be suppressed. In addition, the solubility of the surface of the resist film can be adjusted, and good dimensional uniformity can be achieved.

[0282] [Other ingredients]

[0283] The resist composition of the present invention may contain an amine compound, a sulfonate or a carboxylate as a quencher as needed. In this specification, a quencher refers to a compound that can suppress the diffusion rate of the acid generated from the photoacid generator when it diffuses in the resist film.

[0284] Among such quenchers, the amine compounds include primary, secondary or tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Laid-Open No. 2008-111103, and particularly, amine compounds having any one of a hydroxyl group, an ether group, an ester group, a lactone ring, a cyano group, a sulfonate group, etc. are preferably used. In addition, compounds in which a primary or secondary amine is protected in the form of a carbamate group, such as the compounds described in Japanese Patent No. 3790649, can also be used. Such protected amine compounds are effective when there is a component that is unstable to alkali in the resist composition.

[0285] Examples of the sulfonate salt include compounds represented by the following formula (Z1). Examples of the carboxylate salt include compounds represented by the following formula (Z2).

[0286] [Chemistry 59]

[0287]

[0288] R 101 M is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom, but excludes a group in which the hydrogen atom on the carbon atom at the α position bonded to the sulfonic group is replaced by a fluorine atom or a fluoroalkyl group. + Each is independently an onium cation and examples thereof include the same ones as exemplified above.

[0289] The aforementioned hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include: alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6] Cyclic saturated hydrocarbon groups such as decyl, adamantyl, and adamantylmethyl; alkenyl groups include vinyl, allyl, propenyl, butenyl, hexenyl and the like; unsaturated aliphatic cyclic hydrocarbon groups such as cyclohexenyl; aryl groups such as phenyl, naphthyl, alkylphenyl (2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 4-n-butylphenyl, etc.), dialkylphenyl (2,4-dimethylphenyl, 2,4,6-triisopropylphenyl, etc.), alkylnaphthyl (methylnaphthyl, ethylnaphthyl, etc.), dialkylnaphthyl (dimethylnaphthyl, diethylnaphthyl, etc.); heteroaryl groups such as thienyl; aralkyl groups such as benzyl, 1-phenylethyl, 2-phenylethyl, etc., etc.

[0290] Furthermore, some of the hydrogen atoms in these groups may be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms in these groups may be replaced by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, they may contain hydroxyl groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydrides, haloalkyl groups, and the like. Examples of the hydrocarbon group containing a heteroatom include alkoxyphenyl groups such as 4-hydroxyphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 4-tert-butoxyphenyl, and 3-tert-butoxyphenyl; alkoxynaphthyl groups such as methoxynaphthyl, ethoxynaphthyl, n-propoxynaphthyl, and n-butoxynaphthyl; dialkoxynaphthyl groups such as dimethoxynaphthyl and diethoxynaphthyl; aryl pendant oxyalkyl groups such as 2-aryl-2-oxoethyl groups such as 2-phenyl-2-oxoethyl, 2-(1-naphthyl)-2-oxoethyl, and 2-(2-naphthyl)-2-oxoethyl; and the like.

[0291] R 102 It is a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. 102 The hydrocarbon group represented by R can be exemplified by 101 Other specific examples include fluorine-containing alkyl groups such as trifluoromethyl, trifluoroethyl, 2,2,2-trifluoro-1-methyl-1-hydroxyethyl, and 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl; and fluorine-containing aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl.

[0292] Examples of the sulfonate represented by formula (Z1) include the following, but are not limited thereto.

[0293] [Chemistry 60]

[0294]

[0295] [Chemistry 61]

[0296]

[0297] Examples of the carboxylate represented by the formula (Z2) include the following, but are not limited thereto.

[0298] [Chemistry 62]

[0299]

[0300] When the resist composition of the present invention contains the aforementioned quencher, its content is preferably 0.001 to 12 parts by mass, and more preferably 0.01 to 8 parts by mass, relative to 100 parts by mass of the base resin of component (A). Due to the admixture of the quencher, the adjustment of the resist sensitivity becomes easy, and the diffusion rate of the acid in the resist film can be suppressed and the resolution can be improved, the sensitivity change after exposure can be suppressed, or the substrate and environmental dependence can be reduced, so that the exposure latitude, pattern profile, etc. are improved. In addition, by adding these quenchers, the substrate adhesion can also be improved. The aforementioned quenchers can be used alone or in combination of two or more.

[0301] [Surfactant]

[0302] The resist composition of the present invention may also contain a surfactant that is insoluble or sparingly soluble in water and soluble in an alkali developer and / or a surfactant component that is insoluble or sparingly soluble in water and an alkali developer. Such a surfactant can refer to the (S) definition component described in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2011-16746.

[0303] As for the surfactant that is insoluble or poorly soluble in water and alkali developer, among the surfactants described in the aforementioned gazette, FC-4430 (manufactured by 3M Co., Ltd.), SURFLON (registered trademark) S-381 (manufactured by AGC SEIMI CHEMICAL Co., Ltd.), SURFYNOL (registered trademark) E1004 (manufactured by AIR PRODUCTS Co., Ltd.), KH-20, KH-30 (manufactured by Asahi Glass Co., Ltd.), and the oxetane ring-opening polymer represented by the following structural formula (surf-1) are preferred. These may be used alone or in combination of two or more.

[0304] [Chemistry 63]

[0305]

[0306] However, Rf, R, M, A, B, C, and N in the above formula apply only to this formula.

[0307] In the formula (surf-1), R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. Specific examples of divalent groups include ethylene, tetramethylene, propylene, 2,2-dimethyl-1,3-propanediyl, pentamethylene, and the like. Examples of trivalent or tetravalent groups include those shown below.

[0308] [Chemistry 64]

[0309]

[0310] In the formula, dashed lines represent atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane and pentaerythritol, respectively.

[0311] Among them, tetramethylene or 2,2-dimethyl-1,3-propanediyl is preferably used. Rf is trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. M is an integer of 0 to 3, N is an integer of 1 to 4, and the sum of M and N represents the valence of R, which is an integer of 2 to 4. A is 1, B is an integer of 2 to 25, and C is an integer of 0 to 10. B is preferably an integer of 4 to 20, and C is preferably 0 or 1. In addition, the arrangement of the constituent units of the aforementioned structure is not limited, and they may be blocks or randomly bonded. For details on the manufacture of surfactants of partially fluorinated oxetane ring-opening polymer systems, see the specification of U.S. Patent No. 5,650,483, etc.

[0312] [Pattern Formation Method]

[0313] The present invention further provides a method for forming a pattern using the aforementioned resist composition. When the resist composition of the present invention is used to form a pattern, it can be implemented by using a known photolithography technique. Specifically, the resist composition of the present invention is applied to a substrate (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) for integrated circuit manufacturing, or a substrate (Cr, CrO, CrON, MoSi2, SiO2, etc.) for mask circuit manufacturing by a method such as spin coating, so that the film thickness becomes 0.05 to 2 μm, and then it is pre-baked on a heating plate preferably at 60 to 150° C. for 1 to 10 minutes, and more preferably at 80 to 140° C. for 1 to 5 minutes, to form a resist film.

[0314] Then, a mask for forming a target pattern is placed on the resist film, and high-energy rays such as KrF excimer laser, ArF excimer laser, EUV, EB, etc. with a wavelength of 3 to 15 nm are irradiated so that the exposure amount is preferably 1 to 200 mJ / cm 2 , becomes 10~100mJ / cm 2 More preferably, it is 0.1 to 100 μC / cm 2 , becoming 0.5~50μC / cm 2Better. In addition to the usual exposure method, the exposure can also be carried out by an immersion method in which a liquid with a refractive index of 1.0 or more is inserted between the resist film and the projection lens. A water-insoluble protective film can also be used at this time. Then, post-exposure baking (PEB) is performed on a heating plate at preferably 60 to 150°C for 1 to 5 minutes, preferably 80 to 140°C for 1 to 3 minutes. Then, a developer of an alkaline aqueous solution of tetramethylammonium hydroxide (TMAH) or the like, preferably 0.1 to 5% by mass, preferably 2 to 3% by mass, or an organic solvent developer such as butyl acetate is used, and a common method such as a dip method, a puddle method, or a spray method is used to perform development for preferably 0.1 to 3 minutes, preferably 0.5 to 2 minutes, thereby forming a desired pattern on the substrate.

[0315] The aforementioned water-insoluble protective film is used to prevent elution from the resist film and to improve the water sliding property of the film surface, and is roughly divided into two types. One is an organic solvent stripping type that needs to be stripped using an organic solvent that does not dissolve the resist film before alkali development, and the other is an alkali soluble type that is soluble in an alkali developer and removes the protective film together with the soluble part of the resist film. The latter is a material made of a polymer compound having a 1,1,1,3,3,3-hexafluoro-2-propanol residue that is insoluble in water and soluble in an alkali developer as a base, and is particularly preferably made to dissolve in an alcohol solvent with more than 4 carbon atoms, an ether solvent with 8 to 12 carbon atoms, and a mixed solvent thereof. It can also be made into a material made by dissolving the aforementioned water-insoluble and alkali developer-soluble surfactant in an alcohol solvent with more than 4 carbon atoms, an ether solvent with 8 to 12 carbon atoms, or a mixed solvent thereof.

[0316] In addition, as for the means of pattern formation method, pure water rinsing (postsoak) can be performed after the photoresist film is formed to extract the acid generator from the film surface or wash away the particles, or rinsing (postsoak) can be performed to remove the water remaining on the film after exposure.

[0317] The developer of the pattern forming method of the present invention may be an alkaline aqueous solution of TMAH or the like at preferably 0.1 to 5% by mass, more preferably 2 to 3% by mass, as described above, but an organic solvent may also be used. In this case, negative tone development may be performed to develop / dissolve the unexposed area.

[0318] In the organic solvent development, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, phenyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, pentyl acetate, methyl pentyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl ... At least one of methyl ester, methyl crotonate, ethyl crotonate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and 2-phenylethyl acetate can be used as the developer.

[0319] Example

[0320] Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0321] [1] Synthesis of onium salts

[0322] [Example 1-1] Synthesis of PAG-1

[0323] PAG-1 was synthesized according to the following scheme.

[0324] [Chemistry 65]

[0325]

[0326] Mix 100 g of ammonium salt 1, 68.7 g of cationic intermediate 1, 100 g of pure water and 400 g of dichloromethane, and stir and ripen for 1 hour. After separating and extracting the organic layer, wash it twice with a mixed solution of 5.7 g of cationic intermediate 1 and 100 g of pure water, wash it 5 times with 100 g of pure water, and wash it twice with 100 g of 20 wt% methanol aqueous solution. Concentrate the obtained organic layer, add PGMEA and concentrate it again to prepare a 20 wt% PGMEA solution. After stirring the obtained PGMEA solution at room temperature overnight to precipitate the solid, add 500 g of hexane and stir for 2 hours. Filter the obtained solid, rinse it with 200 g of hexane, and finally dry it by heating under reduced pressure at 50°C to obtain 104.8 g of the target PAG1 (yield 88%). The obtained PAG1 1 HNMR indicates Figure 1 , 19 FNMR stands for Figure 2 .

[0327] IR(D-ATR): ν=3087,3002,2906,2852,1785,1727,1477,1448,1344,1240,1180,1103,1076,1035,1010,997,943,750,684,642,551,522,501cm -1

[0328] [Examples 1-2 to 1-8] Synthesis of other PAGs (PAG-2 to PAG-8)

[0329] PAG-2 to PAG-8 were synthesized using corresponding raw materials according to a known organic synthesis method.

[0330] [Chemistry 66]

[0331]

[0332] [2] Synthesis of polymers

[0333] The polymer used in the resist composition of the present invention was synthesized by the following method: The Mw of the obtained polymer is a polystyrene-equivalent value measured by GPC using THF as a solvent.

[0334] [Synthesis Example 1] Synthesis of Resist Polymer 1

[0335] [Chemistry 67]

[0336]

[0337] Under nitrogen environment, α-methacryloyloxy-γ-butyrolactone (32.5g), 3-hydroxyadamantyl methacrylate (12.9g), 1-ethylcyclopentyl methacrylate (54.6g), and 2,2'-dimethyl azobisisobutyrate (6.27g) were dissolved in PGMEA (155g) to prepare a solution. The solution was added dropwise to PGMEA (78g) stirred at 80°C for 5 hours under nitrogen environment. After the addition was completed, the mixture was stirred at 80°C for 2 hours. After cooling to room temperature, the reaction solution was added dropwise to methanol (2000g). The precipitated solid was filtered and vacuum dried at 50°C for 20 hours to obtain the resist polymer 1 in the form of a white powder solid. The yield was 82g, and the yield was 82%.

[0338] [Synthesis Examples 2 to 5] Synthesis of Resist Polymers 2 to 5

[0339] Resist polymers 2 to 5 shown below were prepared in the same manner as in Synthesis Example 1 except that the types and blending ratios of the monomers were changed.

[0340] [Chemistry 68]

[0341]

[0342] [3] Preparation of resist composition

[0343] [Examples 2-1 to 2-35, Comparative Examples 1-1 to 1-28]

[0344] The onium salt (PAG-1 to PAG-8) of the present invention, comparative photoacid generators PAG-A to PAG-H, resist polymers 1 to 5, other photoacid generators PAG-X to PAG-Z, quenchers Q-1 to Q-4, and alkali-soluble surfactant SF-1 are dissolved in a solvent containing 0.01 mass % of surfactant A (manufactured by OMNOVA) in the composition shown in the following Table 1 to prepare a solution, and the solution is filtered through a 0.2 μm Teflon (registered trademark) filter to prepare a resist composition.

[0345] [Table 1]

[0346]

[0347]

[0348]

[0349]

[0350] In Table 1, the solvent, comparative photoacid generators PAG-A to PAG-H, other photoacid generators PAG-X to PAG-Z, quenchers Q-1 to Q-4, and alkali-soluble surfactant SF-1 are as follows.

[0351] ·PAG-A~PAG-H:

[0352] [Chemistry 69]

[0353]

[0354] ·PAG-X~PAG-Z:

[0355] [Chemistry 70]

[0356]

[0357] SF-1:

[0358] [Chemistry 71]

[0359]

[0360] Q-1~Q-4:

[0361] [Chemistry 72]

[0362]

[0363] Solvent:

[0364] S-1: PGMEA (propylene glycol monomethyl ether acetate)

[0365] S-2: GBL (γ-butyrolactone)

[0366] Surfactant A:

[0367] 3-Methyl-3-(2,2,2-trifluoroethoxymethyl)oxetane·tetrahydrofuran·2,2-dimethyl-1,3-propanediol copolymer (manufactured by OMNOVA)

[0368] [Chemistry 73]

[0369]

[0370] a:(b+b'):(c+c')=1:4~7:0.01~1 (molar ratio)

[0371] Mw=1,500

[0372] [4] Evaluation of resist composition: ArF exposure patterning evaluation (1)

[0373] [Examples 3-1 to 3-24, Comparative Examples 2-1 to 2-18]

[0374] An antireflection film (100 nm film thickness) was formed by coating an antireflection film solution (ARC29A manufactured by Nissan Chemical Industries, Ltd.) on a silicon substrate and baking it at 200°C for 60 seconds. Each resist composition (R-01 to R-24, R-36 to R-53) was spin-coated on the antireflection film and baked at 100°C for 60 seconds using a hot plate to obtain a resist film with a film thickness of 90 nm. This was exposed using an ArF excimer laser scanning exposure machine (manufactured by Nikon Corporation, NSR-S610C, NA=1.30, bipolar, Cr mask) while varying the exposure amount and focus (exposure amount pitch: 1 mJ / cm) on a line and space pattern (LS pattern) with a line width of 40 nm and a pitch of 80 nm on a wafer. 2, focal pitch: 0.025μm) while performing immersion exposure, and after exposure, baking (PEB) at the temperature shown in Table 3 for 60 seconds. In addition, water is used as the immersion liquid. Thereafter, immersion development is performed with a 2.38% by mass TMAH aqueous solution for 30 seconds, rinsed with pure water, spin dried, and a positive pattern is obtained. The LS pattern after development is observed using a Hitachi Advanced Technologies (Co., Ltd.) long-distance SEM (CG4000) to evaluate the sensitivity, exposure latitude, mask error factor (MEF), line width roughness (LWR) and shape according to the following method. The results are shown in Table 2.

[0375] [Sensitivity evaluation]

[0376] In terms of sensitivity, the optimum exposure E for obtaining an LS pattern with a line width of 40 nm and a pitch of 80 nm was determined. op (mJ / cm 2 ) and use it as the sensitivity.

[0377] [Exposure latitude (EL) evaluation]

[0378] In the EL evaluation, the EL (unit: %) was determined by the following formula from the exposure amount formed in the range of ±10% (36 to 44 nm) of the pitch width of 40 nm in the above-mentioned LS pattern.

[0379] EL(%)=(|E1-E2| / E op )×100

[0380] E1: Provides the optimal exposure for LS pattern with line width of 36nm and pitch of 80nm

[0381] E2: Provides the optimal exposure for LS patterns with a line width of 44nm and a pitch of 80nm

[0382] E op :Provide the optimal exposure for LS pattern with line width of 40nm and pitch of 80nm

[0383] [MEF evaluation]

[0384] When the mask size is changed with a fixed pitch, the E op The line width of each pattern irradiated. The slope of the mask size and the pattern line width is called MEF (Mask Error Enhancement Factor). A MEF of about 3.0 or less is defined as good.

[0385] [LWR evaluation]

[0386] For E opThe LS pattern obtained by irradiation was measured at 10 locations in the longitudinal direction of the line, and the value (3σ) three times the standard deviation (σ) was calculated as LWR. The smaller this value is, the smaller the roughness is, and a pattern with a uniform line width can be obtained.

[0387] [Table 2]

[0388]

[0389]

[0390] From the results shown in Table 2, it can be seen that the resist composition containing the onium salt of the present invention as a photoacid generator has good sensitivity, excellent MEF and LWR, and good pattern shape, and is suitable as a material for ArF immersion lithography.

[0391] On the other hand, the resist composition (comparative example) using known photoacid generators PAG-A to PAG-E (see patent documents 1 to 4), PAG-F and PAG-H without heteroatoms in W1, and PAG-G and PAG-H containing heteroatoms in W2 has low EL and insufficient MEF and LWR.

[0392] [5] Evaluation of resist composition: ArF exposure patterning evaluation (2)

[0393] [Examples 4-1 to 4-11, Comparative Examples 3-1 to 3-10]

[0394] Each resist composition (R-25 to R-35, R54 to R63) was spin-coated on a substrate for a three-layer process, on which a spin-coated carbon film ODL-180 (carbon content: 80 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 180 nm, and a spin-coated hard mask SHB-A941 (silicon content: 43 mass%) containing silicon was formed thereon with a film thickness of 35 nm, and baked at 100°C for 60 seconds using a hot plate to form a resist film with a film thickness of 100 nm. The resist film was exposed to light using an ArF excimer laser immersion scanning exposure machine (manufactured by Nikon Co., Ltd., NSR-S610C, NA=1.30, σ0.90 / 0.72, cross-pole opening 35 degrees, azimuthally polarized illumination, 6% half-step phase shift mask, cross-pole illumination) while varying the exposure amount and focus (exposure amount pitch: 1 mJ / cm 2, focal pitch: 0.025μm) while performing exposure of a contact hole pattern (CH pattern) with a size of 45nm and a pitch of 110nm on the wafer, and after exposure, PEB was performed for 60 seconds at the temperature shown in Table 4. In addition, water was used as the immersion liquid. Thereafter, immersion development was performed using n-butyl acetate for 30 seconds, and then rinsed with 4-methyl-2-pentanol, and spin dried to obtain a negative pattern. The CH pattern after development was observed using a Hitachi Advanced Technologies Co., Ltd.-made length measurement SEM (CG4000), and the sensitivity, MEF, and size uniformity (CDU) were evaluated according to the following methods. The results are shown in Table 3.

[0395] [Sensitivity evaluation]

[0396] In terms of sensitivity, the optimum exposure E for obtaining a CH pattern with a hole size of 45 nm and a pitch of 110 nm was determined. op (mJ / cm 2 ). The smaller the value, the higher the sensitivity.

[0397] [MEF evaluation]

[0398] When the mask size is changed with a fixed pitch, the E op The slope of the mask size and the CH pattern size is defined as MEF (Mask Error Enhancement Factor). A MEF of about 3.0 or less is defined as good.

[0399] [CDU evaluation]

[0400] For E op The dimensions of the CH pattern obtained by irradiation are measured at 10 locations (9 CH patterns per location) within the same exposure amount, and the dimensional uniformity (CDU) is calculated as 3 times the standard deviation (σ) (3σ) from the results. The smaller this value is, the better the dimensional uniformity of the CH pattern is.

[0401] [Table 3]

[0402] Resist PEB(℃) <![CDATA[Eop(mJ / cm 2 )]]> MEF CDU(nm) Example 4-1 R-25 90 38 2.4 2.7 Example 4-2 R-26 95 39 2.6 2.6 Example 4-3 R-27 90 38 2.5 2.7 Example 4-4 R-28 90 38 2.4 2.8 Embodiment 4-5 R-29 90 37 2.5 2.8 Embodiment 4-6 R-30 90 39 2.5 2.6 Embodiment 4-7 R-31 90 38 2.6 2.7 Embodiment 4-8 R-32 95 38 2.4 2.7 Embodiment 4-9 R-33 95 40 2.5 2.7 Embodiment 4-10 R-34 90 38 2.5 2.8 Embodiment 4-11 R-35 100 38 2.6 2.7 Comparative Example 3-1 R-54 90 39 3.3 3.9 Comparative Example 3-2 R-55 90 38 3.2 3.9 Comparative Example 3-3 R-56 90 40 3.1 4.1 Comparative Examples 3-4 R-57 95 39 3.4 3.8 Comparative Examples 3-5 R-58 90 39 3.5 3.7 Comparative Examples 3-6 R-59 95 40 3.1 3.7 Comparative Examples 3-7 R-60 100 38 3.2 3.9 Comparative Examples 3-8 R-61 90 38 3.3 3.6 Comparative Examples 3-9 R-62 95 38 3.2 3.5 Comparative Examples 3-10 R-63 90 38 3.2 3.7

[0403] From the results shown in Table 3, it can be seen that the resist composition of the present invention has good sensitivity and excellent MEF and CDU even in negative pattern formation by organic solvent development.

[0404] On the other hand, the resist composition (comparative example) using known photoacid generators PAG-A to PAG-E (see patent documents 1 to 4), PAG-F and PAG-H without heteroatoms in W1, and PAG-G and PAG-H containing heteroatoms in W2, has insufficient MEF and CDU.

[0405] In summary, it is shown that the resist composition of the present invention is also effective in an organic solvent development process.

[0406] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and those having substantially the same configuration as the technical concept described in the claims of the present invention and having the same functions and effects are intended to be included in the technical scope of the present invention.

Claims

1. A resist composition, characterized in that contain: (A) a resin containing a repeating unit having an acid-labile group and containing no repeating unit having an aromatic substituent, (B) a photoacid generator consisting of the photoacid generator represented by the general formula (B-1), or consisting of the photoacid generator represented by the general formula (B-1) and at least one other photoacid generator selected from the group consisting of the photoacid generators represented by the formula (B-2), the formula (B-3) and the formula (B-4), and (C) a solvent; In the formula, W1 represents a cyclic divalent hydrocarbon group containing heteroatoms and having 4 to 12 carbon atoms; W2 represents a cyclic monovalent hydrocarbon group containing no heteroatoms and having 4 to 14 carbon atoms; Rf is a divalent organic group represented by the above general formula; A1 and A2 each independently represent a hydrogen atom or a trifluoromethyl group; B1 and B2 each independently represent a hydrogen atom, a fluorine atom or a trifluoromethyl group; * represents an atomic bond with a carbonyloxy group; m represents 0 to 4, and n represents an integer from 0 to 1; M + represents an onium cation selected from at least one of the cations represented by formula (b1) and formula (b2); The cation represented by formula (b1) is selected from the following: In formula (b2), R 44 ~R 45 Each independently represents a linear, branched or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom; In formula (B-2), A 1 is a hydrogen atom or a trifluoromethyl group; R 21 is a linear, branched or cyclic monovalent hydrocarbon group having 1 to 35 carbon atoms which may contain an oxygen atom, or a nitrogen-containing heterocyclic group, or a group represented by the following formula (i); M + is the onium cation in the above general formula (B-1); In formula (i), R 31 and R 32 Each independently represents a hydrogen atom, or a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; R 31 and R 32 They can also bond to each other and to the nitrogen atoms to which they are bonded to form a ring; R 33 It is a linear, branched or cyclic divalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; In formula (B-3), A 2 is a hydrogen atom or a trifluoromethyl group; R 22 , R 23 and R 24 Each of them is independently a hydrogen atom, or a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; p and q are each independently an integer of 0 to 5; r is an integer of 0 to 4; L is a single bond, an ether group, or a linear, branched, or cyclic divalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; In formula (B-4), A 3 and A 4 are independently a hydrogen atom or a trifluoromethyl group, and are not both hydrogen atoms; R 25 is a linear, branched or cyclic monovalent hydrocarbon group having 1 to 35 carbon atoms which may contain an oxygen atom, or a nitrogen-containing heterocyclic group, or a group represented by the above formula (i); M + It is the onium cation in the above general formula (B-1).

2. The resist composition according to claim 1, wherein W1 in the general formula (B-1) is a cyclic divalent hydrocarbon group having 6 to 12 carbon atoms and containing a lactone ring structure.

3. The resist composition according to claim 1 or 2, wherein W2 in the general formula (B-1) is a polycyclic monovalent hydrocarbon group having 7 to 14 carbon atoms and containing no hetero atom.

4. The resist composition according to claim 1 or 2, wherein The Rf group in the general formula (B-1) is selected from the groups represented by the following formulae (Rf-1) to (Rf-6); * represents an atomic bond to the oxycarbonyl group.

5. The resist composition according to claim 1 or 2, further comprising a component (D) which is a resin different from the resin of the component (A) and is a fluorine-containing resin having at least one type of repeating unit selected from the group consisting of the following formulae (D-1), (D-2) and (D-3); In the formula, R A are independently a hydrogen atom or a methyl group; R 51 and R 52 Each of R is independently a hydrogen atom, or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms; 53 is a single bond, or a linear or branched divalent hydrocarbon group having 1 to 5 carbon atoms; R 54 , R 55 and R 56 R are each independently a hydrogen atom, or a linear, branched or cyclic monovalent hydrocarbon group having 1 to 15 carbon atoms, a fluorinated monovalent hydrocarbon group or an acyl group, or an acid-labile group; 54 , R 55 and R 56 When it is a monovalent hydrocarbon group or a fluorinated monovalent hydrocarbon group, part of their carbon atoms may be substituted by an ether group or a carbonyl group; R 57 It is a linear, branched or cyclic hydrocarbon group or a fluorinated hydrocarbon group having a valence of (v+1) and a carbon number of 1 to 20; v is an integer of 1 to 3.

6. A pattern forming method, characterized by comprising the following steps: The resist composition according to any one of claims 1 to 5 is applied on a substrate and subjected to a heat treatment to form a resist film, exposing the resist film to high energy radiation, and The exposed resist film is developed using a developer.

7. The pattern forming method according to claim 6, wherein: The high-energy radiation is ArF excimer laser light having a wavelength of 193 nm or KrF excimer laser light having a wavelength of 248 nm.

8. The pattern forming method according to claim 6 or 7, wherein: This exposure is an immersion exposure performed by inserting a liquid having a refractive index of 1.0 or more between the resist film and the projection lens.

9. The pattern forming method according to claim 8, further comprising forming a protective film on the resist film, and inserting the liquid between the protective film and a projection lens to perform immersion exposure.

10. The pattern forming method according to claim 6, wherein: The high-energy rays are electron beams or extreme ultraviolet rays with a wavelength of 3 to 15 nm.

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