Resist material and pattern forming method

Abstract

The invention relates to a resist material and a pattern forming method. The present invention addresses the problem of providing: a resist material having high sensitivity regardless of the positive type or the negative type and improved LWR and CDU; and a pattern forming method using the same. [Solution] A resist material containing a dionium salt, a divalent anion containing an onium cation, and a benzene oxide anion structure substituted with an iodine atom and a fluorosulfonic acid anion structure bonded to an aromatic ring of the benzene oxide anion structure.

Description

Technical Field

[0001] The present invention relates to a resist material and a patterning method. Background Art

[0002] With the high integration and high speed of LSIs, the miniaturization of pattern rules has been rapidly progressing. This is because of the spread of high-speed communication of 5G and artificial intelligence (AI), and high-performance devices for processing them have become necessary. In terms of the most advanced miniaturization technology, mass production of devices at the 5nm node and 3nm node by extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm is already in progress. In addition, research using EUV lithography has also been conducted for the next-generation 2nm node devices and the next-next-generation node, and IMEC in Belgium has announced the development of devices.

[0003] With the progress of miniaturization, blurring of images due to acid diffusion has also become a problem. In order to ensure the resolution of fine patterns with a processing size of 45nm or less, it has been proposed that not only the improvement of the dissolution contrast as previously claimed, but also the control of acid diffusion is important (Non-Patent Document 1). However, since chemically amplified resist materials use acid diffusion to improve sensitivity and contrast, if the post-exposure bake (PEB) temperature is lowered or the time is shortened to suppress acid diffusion to the limit, the sensitivity and contrast will be significantly reduced.

[0004] In EUV resist materials, it is necessary to simultaneously achieve high sensitivity, high resolution, and low line width roughness (LWR). If the acid diffusion distance is shortened, the LWR and dimensional uniformity (CDU) will be improved, but the sensitivity will be lowered. For example, by lowering the PEB temperature, the LWR and CDU will be improved, but the sensitivity will be lowered. Increasing the amount of quencher added will also improve the LWR and CDU, but the sensitivity will be lowered. It is necessary to break through the trade-off relationship between sensitivity and LWR.

[0005] Resist materials in which an onium salt containing an anion having an iodine atom or a bromine atom is added as an acid generator have been proposed (Patent Documents 1 to 4). By having an iodine atom with a large absorption of EUV and a bromine atom with high ionization efficiency, the decomposition efficiency of the acid generator during exposure will be increased, and the sensitivity will be increased. The amount of photon absorption increases, and the physical contrast can be improved.

[0006] EUV light with a wavelength of 13.5 nm is a short wavelength of more than one digit compared to ArF excimer laser with a wavelength of 193 nm, so it has high energy and a large influence on the variation in the number of photons (Non-Patent Document 2). Therefore, it has been pointed out that LWR deteriorates (Non-Patent Document 3). In addition, it has also been pointed out that as the miniaturization progresses, the influence of LWR deterioration caused by variations (Resist, Stochastics) in the resist components (polymer, PAG, quencher) (Non-Patent Document 4).

[0007] There has been proposed a resist material (Patent Document 5) containing a polymer formed by bonding an acid generator (PAG) and a quencher (PDQ). By integrating the polymer, PAG, and quencher, the variations present among them are suppressed and LWR and CDU are improved. In addition, there has also been proposed a resist material (Patent Documents 6 and 7) containing an additive formed by bonding PAG and a quencher.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-159744

[0011] [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-5224

[0012] [Patent Document 3] Japanese Patent Application Laid-Open No. 2018-25789

[0013] [Patent Document 4] Japanese Patent Application Laid-Open No. 2019-3175

[0014] [Patent Document 5] Japanese Patent Application Laid-Open No. 2022-115072

[0015] [Patent Document 6] Japanese Patent Application Laid-Open No. 2015-24989

[0016] [Patent Document 7] International Publication No. 2020 / 158313

[0017] Non-Patent Documents

[0018] [Non-Patent Document 1] SPIE Vol.6520 65203L-1(2007)

[0019] [Non-Patent Document 2] SPIE Vol.3331 535(1998)

[0020] [Non-Patent Document 3] SPIE Vol.7273 727343-1(2009)

[0021] [Non-Patent Document 4] SPIE Vol.9776 97760V-1(2016) Summary of the Invention

[0022] [Problems to be Solved by the Invention]

[0023] It is desired to develop a resist material that is more sensitive than known resist materials and can improve the LWR of line patterns and the CDU of hole patterns.

[0024] The present invention has been made in view of the above circumstances, and an object thereof is to provide a resist material that is highly sensitive both for positive and negative types, and has improved LWR and CDU, and to provide a pattern forming method using the same.

[0025] [Means for Solving the Problems]

[0026] As a result of repeated and in-depth studies by the inventors of the present application in order to achieve the above object, it has been found that: by using a bis-onium salt containing a divalent anion having a phenoxide anion structure substituted with an iodine atom and a fluorosulfonic acid anion structure bonded to the phenoxide anion structure, and an onium cation as an acid generator and a quencher, upon exposure to radiation, the acid generator is directly excited, and there is no influence of the diffusion of secondary electrons, whereby a resist material having high sensitivity, improved LWR and CDU, high contrast, excellent resolution, and a wide process latitude can be obtained, and thus the present invention has been completed.

[0027] That is, the present invention provides the following resist material and pattern forming method.

[0028] 1. A resist material, comprising:

[0029] A bis-onium salt containing a divalent anion having a phenoxide anion structure substituted with an iodine atom and a fluorosulfonic acid anion structure bonded to the phenoxide anion structure, and an onium cation.

[0030] 2. The resist material according to 1., wherein the bis-onium salt is represented by the following formula (1).

[0031] [Chemical Formula 1]

[0032]

[0033] In the formula, m is an integer of 1 to 4. n is an integer of 0 to 3. However, 1 ≤ m + n ≤ 4. p is 0 or 1.

[0034] X 1 and X 2 are each independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, or a carbamate bond.

[0035] R1 is a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom other than an iodine atom, a nitro group or a cyano group, and the hydrocarbon group may also have at least 1 kind selected from a halogen atom, an oxygen atom, a sulfur atom and a nitrogen atom.

[0036] R 2 is a single bond or a C1-C40 alkylene group, and the alkylene group may also contain at least 1 kind selected from an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom.

[0037] Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group. However, when p is 0, at least one of Rf 3 and Rf 4 is a fluorine atom or a trifluoromethyl group, and when p is 1, at least one of Rf 1 ~Rf 4 is a fluorine atom or a trifluoromethyl group. Further, Rf 1 and Rf 2 may also combine to form a carbonyl group.

[0038] M + is a sulfonium cation or an iodonium cation.

[0039] 3. The resist material according to 1. or 2., further comprising a base polymer.

[0040] 4. The resist material according to 3., wherein the base polymer contains a repeating unit represented by the following formula (a1) or (a2).

[0041] [Chemical formula 2]

[0042]

[0043] In the formula, R A are each independently a hydrogen atom or a methyl group.

[0044] Y 1 is a single bond, a phenylene group or a naphthylene group, or a C1-C12 linking group containing at least 1 kind selected from an ester bond, an ether bond and a lactone ring, and the phenylene group, naphthylene group and linking group may also have at least 1 kind selected from a hydroxyl group, a C1-C8 saturated hydrocarbon group oxy group and a C2-C8 saturated hydrocarbon group carbonyl oxy group.

[0045] Y 2 is a single bond or an ester bond.

[0046] Y 3 is a single bond, an ether bond or an ester bond.

[0047] R 11 and R 12 are each independently an acid-labile group.

[0048] R 13 is a saturated hydrocarbon group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbon group carbonyl having 2 to 5 carbon atoms, a cyano group or a saturated hydrocarbon group oxycarbonyl having 2 to 5 carbon atoms.

[0049] R 14 is a single bond or an alkanediyl having 1 to 6 carbon atoms, and the alkanediyl may also contain an ether bond or an ester bond.

[0050] a is an integer from 0 to 4.

[0051] 5. The resist material as described in 4., which is a chemically amplified positive resist material.

[0052] 6. The resist material as described in 3., wherein the aforementioned base polymer does not contain acid-labile groups.

[0053] 7. The resist material as described in 6., which is a chemically amplified negative resist material.

[0054] 8. The resist material as described in any one of 1. to 7. further contains an organic solvent.

[0055] 9. The resist material as described in any one of 1. to 8. further contains a quencher.

[0056] 10. The resist material as described in any one of 1. to 9. further contains an acid generator.

[0057] 11. The resist material as described in any one of 1. to 10. further contains a surfactant.

[0058] 12. A pattern forming method, comprising the following steps:

[0059] Forming a resist film on a substrate using the resist material as described in any one of 1. to 11.,

[0060] Exposing the aforementioned resist film with high-energy rays, and

[0061] Developing the aforementioned exposed resist film using a developer.

[0062] 13. The pattern forming method as described in 12., wherein the aforementioned high-energy rays are an ArF excimer laser with a wavelength of 193 nm, a KrF excimer laser with a wavelength of 248 nm, an electron beam (EB) or EUV with a wavelength of 3 to 15 nm.

[0063] [Effects of the Invention]

[0064] A resist film containing a dication salt having a divalent anion with a fluorosulfonic acid anion structure containing a phenoxide anion structure substituted with an iodine atom and an aromatic ring bonded to the phenoxide anion structure, and an onium cation has the characteristics of being directly excited during exposure due to a large absorption of EUV light and inhibiting acid diffusion. Thereby, a reduction in resolution caused by secondary electrons and blurring of acid diffusion can be prevented. Since the aforementioned dication salt is in a form in which an acid generator that is an onium salt generating sulfonic acid and a quencher that is an onium salt generating iodinated phenol are bonded and the acid generator and the quencher are always arranged at a certain distance, the aforementioned Resist Stochastics is improved, and thereby LWR and CDU can be improved. By having an iodine atom on the quencher side, the absorption on the quencher side is higher and the decomposition efficiency on the quencher side is higher than that on the acid generator side. Thereby, a resist material with high sensitivity and improved LWR and CDU can be constructed. Detailed Description of the Invention

[0065] [Resist Material]

[0066] The resist material of the present invention contains a dication salt having a divalent anion with a fluorosulfonic acid anion structure containing a phenoxide anion structure substituted with an iodine atom and an aromatic ring bonded to the phenoxide anion structure, and an onium cation. The aforementioned dication salt is an acid generator-cum-quencher having the functions of both an acid generator and a quencher, and due to the light absorption by the iodine atom, the high reactivity of fluorosulfonic acid, and the interaction of acid diffusion control caused by the presence of the quencher nearby all the time, the acid diffusion is small and the diffusion distance is uniform. Thereby, LWR and CDU can be improved.

[0067] The improvement effects of LWR and CDU brought about by the dication salt used in the present invention are effective in any of positive pattern formation by alkaline aqueous solution development, negative pattern formation, and negative pattern formation in organic solvent development.

[0068] [Dication Salt]

[0069] The aforementioned dication salt is preferably represented by the following formula (1).

[0070] [Chemical Formula 3]

[0071]

[0072] In formula (1), m is an integer from 1 to 4. n is an integer from 0 to 3. However, 1 ≤ m + n ≤ 4. p is 0 or 1.

[0073] In formula (1), X 1 and X 2 are each independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, or a carbamate bond. Among them, X 1is preferably a single bond, an ether bond, an ester bond or a sulfonate bond, X 2 is preferably a single bond, an ether bond or an ester bond.

[0074] In formula (1), R 1 is a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom other than an iodine atom, a nitro group or a cyano group, and the hydrocarbon group may also have at least one selected from a halogen atom, an oxygen atom, a sulfur atom and a nitrogen atom.

[0075] R 1 Specific examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, etc. R 1 The hydrocarbon group represented by R may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl; cyclic saturated hydrocarbon groups having 3 to 10 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl; alkenyl groups having 2 to 10 carbon atoms such as vinyl, propenyl, butenyl, hexenyl; alkynyl groups having 2 to 10 carbon atoms such as ethynyl, propynyl, butynyl; cyclic unsaturated aliphatic hydrocarbon groups having 3 to 10 carbon atoms such as cyclohexenyl, norbornenyl; aryl groups having 6 to 10 carbon atoms such as phenyl, tolyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl; aralkyl groups having 7 to 10 carbon atoms such as benzyl, phenethyl; groups obtained by combining them, etc.

[0076] In formula (1), R 2 is a single bond or a divalent hydrocarbon group having 1 to 40 carbon atoms, and the divalent hydrocarbon group may also contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom.

[0077] R 2The represented alkylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, 1-methylethane-1,2-diyl, 1-ethylethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, 2-methylpropane-1,1-diyl, butane-1,3-diyl, butane-1,4-diyl, butane-2,3-diyl, 1,1-dimethylpropane-1,3-diyl, 2,2-dimethylpropane-1,3-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, pentadecane-1,15-diyl, hexadecane-1,16-diyl, heptadecane-1,17-diyl, octadecane-1,18-diyl, nonadecane-1,19-diyl, eicosane-1,20-diyl, etc., alkanediyl groups having 1 to 40 carbon atoms; cyclopentanediyl, cyclohexanediyl, bicyclo[2.2.2]octanediyl, norbornanediyl, adamantanediyl, etc., cyclic saturated alkylene groups having 3 to 40 carbon atoms; ethylenediyl, propylenediyl, butylenediyl, etc., alkenediyl groups having 2 to 40 carbon atoms; acetylenediyl, propynediyl, butynediyl, etc., alkynediyl groups having 2 to 40 carbon atoms; cyclohexenediyl, bicyclo[2.2.2]octenediyl, norbornenediyl, etc., cyclic unsaturated aliphatic alkylene groups having 3 to 40 carbon atoms; phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, 9,10-dihydro-9,10-ethanoanthracenediyl, etc., arylene groups having 6 to 40 carbon atoms; groups obtained by combining them, etc.

[0078] In formula (1), Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. However, when p is 0, at least one of Rf 3 and Rf 4 is a fluorine atom or a trifluoromethyl group, and when p is 1, at least one of Rf 1 ~Rf 4 is a fluorine atom or a trifluoromethyl group. Further, Rf 1 and Rf 2 may also combine to form a carbonyl group.

[0079] Specific examples of the anion of the aforementioned dication salt are as follows, but are not limited thereto.

[0080] [Chemical formula 4]

[0081]

[0082] [Chemical Formula 5]

[0083]

[0084] [Chemical Formula 6]

[0085]

[0086] [Chemical Formula 7]

[0087]

[0088] [Chemical Formula 8]

[0089]

[0090] [Chemical Formula 9]

[0091]

[0092] [Chemical Formula 10]

[0093]

[0094] [Chemical Formula 11]

[0095]

[0096] [Chemical Formula 12]

[0097]

[0098] [Chemical Formula 13]

[0099]

[0100] [Chemical Formula 14]

[0101]

[0102] [Chemical Formula 15]

[0103]

[0104] [Chemical Formula 16]

[0105]

[0106] [Chemical Formula 17]

[0107]

[0108] [Chemical Formula 18]

[0109]

[0110] [Chemical Formula 19]

[0111]

[0112] [Chemical Formula 20]

[0113]

[0114] [Chemical Formula 21]

[0115]

[0116] [Chemical Formula 22]

[0117]

[0118] [Chemical Formula 23]

[0119]

[0120] [Chemical Formula 24]

[0121]

[0122] [Chemical Formula 25]

[0123]

[0124] [Chemical Formula 26]

[0125]

[0126] [Chemical Formula 27]

[0127]

[0128] [Chemical Formula 28]

[0129]

[0130] [Chemical Formula 29]

[0131]

[0132] [Chemical Formula 30]

[0133]

[0134] [Chemical Formula 31]

[0135]

[0136] [Chemical Formula 32]

[0137]

[0138] [Chemical Formula 33]

[0139]

[0140] [Chemical formula 34]

[0141]

[0142] [Chemical formula 35]

[0143]

[0144] [Chemical formula 36]

[0145]

[0146] [Chemical formula 37]

[0147]

[0148] [Chemical formula 38]

[0149]

[0150] [Chemical formula 39]

[0151]

[0152] [Chemical formula 40]

[0153]

[0154] In formula (1), M + is a sulfonium cation or an iodonium cation. Among two Ms + , one may be a sulfonium cation and the other may be an iodonium cation, or both may be sulfonium cations, or both may be iodonium cations. When both of the two Ms + are sulfonium cations, they may be the same as each other or different from each other. Also, when both of the two Ms + are iodonium cations, they may be the same as each other or different from each other.

[0155] The aforementioned sulfonium cation is preferably the one represented by the following formula (2), and the aforementioned iodonium cation is preferably the one represented by the following formula (3).

[0156] [Chemical formula 41]

[0157]

[0158] In formulas (2) and (3), R 3 ~R 7 are each independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom.

[0159] R 3 ~R7 Specific examples of the halogen atom represented include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.

[0160] R 3 ~R 7 The hydrocarbon group having 1 to 20 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group, a n-hexyl group, a n-octyl group, a n-nonyl group, a n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an eicosyl group; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, and an adamantyl group; alkenyl groups having 2 to 20 carbon atoms such as a vinyl group, an allyl group, a butenyl group, and a hexenyl group; alkynyl groups having 2 to 20 carbon atoms such as an ethynyl group, a propynyl group, and a butynyl group; cyclic unsaturated aliphatic hydrocarbon groups having 3 to 20 carbon atoms such as a cyclohexenyl group and a norbornenyl group; aryl groups having 6 to 20 carbon atoms such as a phenyl group, a tolyl group, an ethylphenyl group, a n-propylphenyl group, an isopropylphenyl group, a n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, a n-propylnaphthyl group, an isopropylnaphthyl group, a n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, and a tert-butylnaphthyl group; aralkyl groups having 7 to 20 carbon atoms such as a benzyl group and a phenethyl group; groups obtained by combining them, etc.

[0161] Further, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of -CH2- of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, it may also contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a mercapto group, a pentafluorothio group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0162] Further, R 3 and R 4 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. In this case, the aforementioned ring is preferably one having the following structure.

[0163] [Chemical formula 42]

[0164]

[0165] In the formula, the dotted line represents an atomic bond.

[0166] M + Specific examples of the sulfonium cation represented include those shown below, but are not limited thereto.

[0167] [Chemical Formula 43]

[0168]

[0169] [Chemical Formula 44]

[0170]

[0171] [Chemical Formula 45]

[0172]

[0173] [Chemical Formula 46]

[0174]

[0175] [Chemical Formula 47]

[0176]

[0177] [Chemical Formula 48]

[0178]

[0179] [Chemical Formula 49]

[0180]

[0181] [Chemical Formula 50]

[0182]

[0183] [Chemical Formula 51]

[0184]

[0185] [Chemical Formula 52]

[0186]

[0187] [Chemical Formula 53]

[0188]

[0189] [Chemical Formula 54]

[0190]

[0191] [Chemical Formula 55]

[0192]

[0193] [Chemical Formula 56]

[0194]

[0195] [Chemical Formula 57]

[0196]

[0197] [Chemical Formula 58]

[0198]

[0199] [Chemical Formula 59]

[0200]

[0201] [Chemical Formula 60]

[0202]

[0203] [Chemical Formula 61]

[0204]

[0205] [Chemical Formula 62]

[0206]

[0207] [Chemical Formula 63]

[0208]

[0209] [Chemical Formula 64]

[0210]

[0211] [Chemical Formula 65]

[0212]

[0213] [Chemical Formula 66]

[0214]

[0215] [Chemical Formula 67]

[0216]

[0217] [Chemical Formula 68]

[0218]

[0219] [Chemical Formula 69]

[0220]

[0221] [Chemical Formula 70]

[0222]

[0223] [Chemical Formula 71]

[0224]

[0225] [Chemical formula 72]

[0226]

[0227] [Chemical formula 73]

[0228]

[0229] [Chemical formula 74]

[0230]

[0231] M + Specific examples of the sulfonium cations represented are as follows, but are not limited thereto.

[0232] [Chemical formula 75]

[0233]

[0234] [Chemical formula 76]

[0235]

[0236] Examples of the method for synthesizing the aforementioned bis-onium salt include: a method of performing salt exchange between a sulfonium salt or sulfonium salt containing a halide anion and an ammonium salt containing a divalent anion having a phenoxide anion structure substituted with an iodine atom and a fluorosulfonic acid anion structure bonded to the phenoxide anion structure.

[0237] In the resist material of the present invention, the content of the aforementioned bis-onium salt is preferably 0.01 to 1000 parts by mass, more preferably 0.05 to 500 parts by mass, based on 100 parts by mass of the base polymer described later, considering the viewpoints of sensitivity and acid diffusion inhibition effect.

[0238] [Base polymer]

[0239] The base polymer contained in the resist material of the present invention, in the case of a positive resist material, contains a repeating unit having an acid-labile group. The repeating unit having an acid-labile group is preferably a repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1) or a repeating unit represented by formula (a2) (hereinafter also referred to as repeating unit a2).

[0240] [Chemical formula 77]

[0241]

[0242] In formulas (a1) and (a2), R A are each independently a hydrogen atom or a methyl group. Y 1is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one selected from an ester bond, an ether bond, and a lactone ring, and the phenylene group, naphthylene group, and linking group may also have at least one selected from a hydroxyl group, a saturated hydrocarbon group oxy group having 1 to 8 carbon atoms, and a saturated hydrocarbon group carbonyl oxy group having 2 to 8 carbon atoms. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond, or an ester bond. R 11 and R 12 are each independently an acid-labile group. R 13 is a saturated hydrocarbon group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbon group carbonyl having 2 to 5 carbon atoms, a cyano group, or a saturated hydrocarbon group oxycarbonyl having 2 to 5 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may also contain an ether bond or an ester bond. a is an integer of 0 to 4.

[0243] Specific examples of the monomer providing the repeating unit a1 are as follows, but are not limited thereto. In addition, in the following formula, R A and R 11 are the same as described above.

[0244] [Chemical formula 78]

[0245]

[0246] [Chemical formula 79]

[0247]

[0248] [Chemical formula 80]

[0249]

[0250] Specific examples of the monomer providing the repeating unit a2 are as follows, but are not limited thereto. In addition, in the following formula, R A and R 12 are the same as described above.

[0251] [Chemical formula 81]

[0252]

[0253] The acid-labile groups represented by R 11 and R 12 in the repeating units a1 and a2 include, for example, those described in JP-A-2013-80033 and JP-A-2013-83821.

[0254] Typically, specific examples of the acid-labile group include those represented by any of the following formulas (AL-1) to (AL-3).

[0255] [Chemical Formula 82]

[0256]

[0257] In the formula, the dashed line represents an atomic bond.

[0258] In formulas (AL-1) and (AL-2), R L1 and R L2 are each independently a hydrocarbon group having 1 to 40 carbon atoms, and may also contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be any of linear, branched, and cyclic. The aforementioned hydrocarbon group is preferably a saturated hydrocarbon group having 1 to 40 carbon atoms, more preferably a saturated hydrocarbon group having 1 to 20 carbon atoms.

[0259] In formula (AL-1), b is an integer from 0 to 10, preferably an integer from 1 to 5.

[0260] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and may also contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be any of linear, branched, and cyclic. The aforementioned hydrocarbon group is preferably a saturated hydrocarbon group having 1 to 20 carbon atoms. Also, any two of R L2 , R L3 and R L4 may also be bonded to each other and form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded or together with a carbon atom and an oxygen atom. The aforementioned ring is preferably a ring having 4 to 16 carbon atoms, particularly preferably an alicyclic ring.

[0261] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbon group having 1 to 20 carbon atoms, and may also contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be any of linear, branched, and cyclic. The aforementioned hydrocarbon group is preferably a saturated hydrocarbon group having 1 to 20 carbon atoms. Also, any two of R L5 , R L6 and R L7 may also be bonded to each other and form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. The aforementioned ring is preferably a ring having 4 to 16 carbon atoms, particularly preferably an alicyclic ring.

[0262] The aforementioned base polymer may also contain a repeating unit b having a phenolic hydroxyl group as a bonding group. Specific examples of the monomer providing the repeating unit b are as shown below, but are not limited thereto. In addition, in the following formula, R A is the same as the aforementioned.

[0263] [Chemical Formula 83]

[0264]

[0265] The aforementioned base polymer may also contain repeating units c of other adhesion groups such as hydroxyl groups other than phenolic hydroxyl groups, lactone rings, sultone rings, ether bonds, ester bonds, sulfonate ester bonds, carbonyl groups, sulfonyl groups, cyano groups, or carboxyl groups. Specific examples of the monomers providing the repeating units c are as shown below, but are not limited thereto. In addition, in the following formula, R A is the same as the aforementioned.

[0266] [Chemical formula 84]

[0267]

[0268] [Chemical formula 85]

[0269]

[0270] [Chemical formula 86]

[0271]

[0272] [Chemical formula 87]

[0273]

[0274] [Chemical formula 88]

[0275]

[0276] [Chemical formula 89]

[0277]

[0278] [Chemical formula 90]

[0279]

[0280] [Chemical formula 91]

[0281]

[0282] The aforementioned base polymer may also contain repeating units d derived from indene, benzofuran, benzothiophene, acenaphthene, chromone, coumarin, norbornadiene, or their derivatives. Specific examples of the monomers providing the repeating units d are as shown below, but are not limited thereto.

[0283] [Chemical formula 92]

[0284]

[0285] The aforementioned base polymer may also contain repeating unit e derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methylenedihydroindene, vinylpyridine or vinylcarbazole.

[0286] The aforementioned base polymer may also contain repeating unit f derived from an onium salt having a polymerizable unsaturated bond. Specific examples of preferable repeating unit f include: a repeating unit represented by the following formula (f1) (hereinafter also referred to as repeating unit f1), a repeating unit represented by the following formula (f2) (hereinafter also referred to as repeating unit f2), a repeating unit represented by the following formula (f3) (hereinafter also referred to as repeating unit f3), a repeating unit represented by the following formula (f4) (hereinafter also referred to as repeating unit f4), and a repeating unit represented by the following formula (f5) (hereinafter also referred to as repeating unit f5). In addition, repeating units f1 to f5 may be used alone or in combination of two or more.

[0287] [Chemical formula 93]

[0288]

[0289] In formulas (f1) to (f5), R A is independently a hydrogen atom or a methyl group.

[0290] In formulas (f1) to (f3), Z 1 is a single bond, an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, a group having 7 to 18 carbon atoms obtained by combining them, or -O-Z 11 -, -C(=O)-O-Z 11 - or -C(=O)-NH-Z 11 -. Z 11 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining them, and may also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -O-C(=O)-. Z 31 is an aliphatic alkylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining them, and may also contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. Z 4 is a methylene group, 2,2,2-trifluoro-1,1-ethanediyl, or a carbonyl group. Z 5 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 -. Z51 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond, a halogen atom, or a hydroxyl group. Further, Z 1 , Z 11 , Z 31 and Z 51 The aliphatic alkylene group represented may be saturated or unsaturated, and may be linear, branched, or cyclic.

[0291] In formulas (f4) and (f5), Z 6 is a single bond, a phenylene group, a naphthylene ring, an ester bond, or an amide bond.

[0292] In formula (f4), Z 7A is a single bond or a divalent organic group having 1 to 24 carbon atoms, and may also have at least one selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom.

[0293] Z 7A The divalent organic group represented may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkylene groups having 1 to 24 carbon atoms in which part or all of the hydrogen atoms are substituted with iodine atoms or bromine atoms. Specific examples of the alkylene group having 1 to 24 carbon atoms include: methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, 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, pentadecane-1,15-diyl, hexadecane-1,16-diyl, heptadecane-1,17-diyl, octadecane-1,18-diyl, nonadecane-1,19-diyl, icosane-1,20-diyl, etc. alkanediyls; cyclopentanediyl, methylcyclopentanediyl, dimethylcyclopentanediyl, trimethylcyclopentanediyl, tetramethylcyclopentanediyl, cyclohexanediyl, methylcyclohexanediyl, dimethylcyclohexanediyl, trimethylcyclohexanediyl, tetramethylcyclohexanediyl, norbornanediyl, adamantanediyl, etc. cyclic saturated alkylene groups; phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, tert-butylnaphthylene, biphenyldiyl, methylbiphenyldiyl, dimethylbiphenyldiyl, etc. arylene groups; groups obtained by combining them, etc. Further, Z 7APart or all of the hydrogen atoms may also be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, Z 7A Part of the -CH2- may also be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, it may also contain a hydroxyl group, an ester bond, an ether bond, an amide bond, a urethane bond, a urea bond, etc.

[0294] In formula (f5), Z 7B is a monovalent organic group having 1 to 10 carbon atoms and may also have at least one selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom.

[0295] Z 7B The monovalent organic group represented may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include a hydrocarbon group having 1 to 10 carbon atoms in which part or all of the hydrogen atoms are substituted with an iodine atom or a bromine atom. Specific examples of the hydrocarbon group having 1 to 10 carbon atoms include: alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, 3-pentyl, tert-pentyl, neopentyl, n-hexyl, n-octyl, n-nonyl, n-decyl; cyclic saturated hydrocarbon groups having 3 to 10 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, norbornyl, cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl, cyclobutylethyl, cyclopentylmethyl, cyclopentylethyl, cyclohexylmethyl, cyclohexylethyl, methylcyclopropyl, methylcyclobutyl, methylcyclopentyl, methylcyclohexyl, ethylcyclopropyl, ethylcyclobutyl, ethylcyclopentyl, ethylcyclohexyl; alkenyl groups having 2 to 10 carbon atoms such as vinyl, 1-propenyl, 2-propenyl, butenyl, pentenyl, hexenyl, heptenyl, nonenyl, decenyl; alkynyl groups having 2 to 10 carbon atoms such as ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl; cyclic unsaturated aliphatic hydrocarbon groups having 3 to 10 carbon atoms such as cyclopentenyl, cyclohexenyl, methylcyclopentenyl, methylcyclohexenyl, ethylcyclopentenyl, ethylcyclohexenyl, norbornene; aryl groups having 6 to 10 carbon atoms such as phenyl, tolyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl; aralkyl groups having 7 to 10 carbon atoms such as benzyl, phenethyl, phenylpropyl, phenylbutyl; groups obtained by combining them, etc. Further, 7B Part or all of the hydrogen atoms may also be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, Z 7B Part of the -CH2- may also be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, it may also contain a hydroxyl group, an ester bond, an ether bond, an amide bond, a urethane bond, a urea bond, etc.

[0296] In formulas (f4) and (f5), Z8 is a single bond, an ether bond, an ester bond, a thioether bond or an alkanediyl having 1 to 6 carbon atoms.

[0297] In formula (f5), Z 9 is a trivalent organic group having 1 to 12 carbon atoms, and may also have at least one selected from an oxygen atom, a nitrogen atom and a sulfur atom. Z 9 The trivalent organic group represented may be saturated or unsaturated, and may be any of linear, branched and cyclic. Specific examples thereof may include groups obtained by further removing one hydrogen atom from an alkylene group having 1 to 12 carbon atoms. Specific examples of the alkylene group having 1 to 12 carbon atoms may include those having 1 to 12 carbon atoms among the alkylene groups having 1 to 24 carbon atoms described above. Further, a part or all of the hydrogen atoms of Z 9 may also be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom and a sulfur atom, and a part of the -CH2- of Z 9 may also be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom and a sulfur atom, and as a result, it may contain a hydroxyl group, an ester bond, an ether bond, an amide bond, a urethane bond, a urea bond, etc.

[0298] In formulas (f1) to (f5), R 21 to R 25 are each independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Specific examples of the halogen atom may include: a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. The hydrocarbon group may be saturated or unsaturated, and may be any of linear, branched and cyclic. Specific examples thereof may include the same examples as those of the hydrocarbon groups exemplified in the descriptions of formulas (2) and (3) as R 3 to R 7 represented. Further, a part or all of the hydrogen atoms of the hydrocarbon group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of the -CH2- of the hydrocarbon group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. In addition, R 23 and R 24 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. At this time, specific examples of the ring may include the same examples as those of the rings that can be formed when R 3 and R 4 are bonded to each other and form a ring together with the sulfur atom to which they are bonded as exemplified in the description of formula (2).

[0299] In formulas (f4) and (f5), R 26Each is independently a saturated hydrocarbon group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group or a nitro group.

[0300] In formulae (f4) and (f5), the circular R is a (j + 2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. Specific examples of the (j + 2)-valent aromatic hydrocarbon group include groups obtained by detaching (j + 2) hydrogen atoms from aromatic hydrocarbons such as benzene and naphthalene.

[0301] In formulae (f4) and (f5), j is independently an integer from 0 to 5.

[0302] In formula (f1), M - is a non-nucleophilic counter ion. Specific examples of the non-nucleophilic counter ion include: halide ions such as chloride ion and bromide ion; fluoroalkylsulfonate ions such as trifluoromethanesulfonate ion, 1,1,1-trifluoroethanesulfonate ion and nonafluorobutanesulfonate ion; arylsulfonate ions such as toluenesulfonate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion and 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as methanesulfonate ion and butanesulfonate ion; imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion and bis(perfluorobutylsulfonyl)imide ion; methylation ions such as tris(trifluoromethylsulfonyl)methylation ion and tris(perfluoroethylsulfonyl)methylation ion.

[0303] More specific examples of the non-nucleophilic counter ion include: sulfonate ions in which the α-position is substituted with a fluorine atom represented by the following formula (f1-1), sulfonate ions in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group represented by the following formula (f1-2), and the like.

[0304] [Chemical formula 94]

[0305]

[0306] In formula (f1-1), R 31 is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may also contain at least one selected from an ether bond, an ester bond, a carbonyl group, a lactone ring and a fluorine atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include the same examples as the hydrocarbon groups represented by R f a 1 shown later.

[0307] In formula (f1-2), R 32is a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a hydrocarbon group carbonyl having 2 to 30 carbon atoms, and the hydrocarbon group and the hydrocarbon group carbonyl may also contain at least one selected from an ether bond, an ester bond, a carbonyl group, and a lactone ring. The hydrocarbon moiety of the aforementioned hydrocarbon group and hydrocarbon group carbonyl may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same examples as those exemplified as R in the following formula (1A'). f a 1 The same examples as those of the hydrocarbon group represented by

[0308] Specific examples of the cation of the monomer providing the repeating unit f1 are as follows, but are not limited thereto. In addition, in the following formula, R A is the same as the aforementioned one.

[0309] [Chemical formula 95]

[0310]

[0311] Specific examples of the cations of the repeating units f2 to f5 are the same as those exemplified as the cations of the onium salts represented by the formula (1).

[0312] Specific examples of the anion of the monomer providing the repeating unit f2 are as follows, but are not limited thereto. In addition, in the following formula, R A is the same as the aforementioned one.

[0313] [Chemical formula 96]

[0314]

[0315] [Chemical formula 97]

[0316]

[0317] [Chemical formula 98]

[0318]

[0319] [Chemical formula 99]

[0320]

[0321] [Chemical formula 100]

[0322]

[0323] [Chemical formula 101]

[0324]

[0325] [Chemical formula 102]

[0326]

[0327] [Chemical formula 103]

[0328]

[0329] [Chemical formula 104]

[0330]

[0331] [Chemical formula 105]

[0332]

[0333] [Chemical formula 106]

[0334]

[0335] [Chemical formula 107]

[0336]

[0337] [Chemical formula 108]

[0338]

[0339] [Chemical formula 109]

[0340]

[0341] [Chemical formula 110]

[0342]

[0343] Specific examples of the anion of the monomer providing the repeating unit f3 are as follows, but are not limited thereto. In addition, in the following formula, R A is the same as described above.

[0344] [Chemical formula 111]

[0345]

[0346] Specific examples of the anion of the monomer providing the repeating unit f4 or f5 are as follows, but are not limited thereto. In addition, in the following formula, R A and X BI are the same as described above.

[0347] [Chemical formula 112]

[0348]

[0349] [Chemical formula 113]

[0350]

[0351] [Chemical formula 114]

[0352]

[0353] [Chemical Formula 115]

[0354]

[0355] [Chemical Formula 116]

[0356]

[0357] [Chemical Formula 117]

[0358]

[0359] [Chemical Formula 118]

[0360]

[0361] [Chemical Formula 119]

[0362]

[0363] [Chemical Formula 120]

[0364]

[0365] [Chemical Formula 121]

[0366]

[0367] [Chemical Formula 122]

[0368]

[0369] [Chemical Formula 123]

[0370]

[0371] [Chemical Formula 124]

[0372]

[0373] [Chemical Formula 125]

[0374]

[0375] [Chemical Formula 126]

[0376]

[0377] [Chemical Formula 127]

[0378]

[0379] [Chemical Formula 128]

[0380]

[0381] [Chemical Formula 129]

[0382]

[0383] [Chemical Formula 130]

[0384]

[0385] [Chemical Formula 131]

[0386]

[0387] [Chemical Formula 132]

[0388]

[0389] [Chemical Formula 133]

[0390]

[0391] [Chemical Formula 134]

[0392]

[0393] [Chemical Formula 135]

[0394]

[0395] [Chemical Formula 136]

[0396]

[0397] The repeating units f1 to f5 function as acid generators. By bonding the acid generator to the polymer main chain, acid diffusion can be reduced, and a decrease in resolution due to blurring of acid diffusion can be prevented. Also, by uniformly dispersing the acid generator, LWR and CDU are improved.

[0398] The base polymer for a positive resist material requires repeating unit a1 or a2 containing acid-labile groups. At this time, the content ratios of repeating units a1, a2, b, c, d, e, and f should be 0 ≤ a1 < 1.0, 0 ≤ a2 < 1.0, 0 < a1 + a2 < 1.0, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.9, 0 ≤ d ≤ 0.8, 0 ≤ e ≤ 0.8, and 0 ≤ f ≤ 0.5. It is more preferable that 0 ≤ a1 ≤ 0.9, 0 ≤ a2 ≤ 0.9, 0.1 ≤ a1 + a2 ≤ 0.9, 0 ≤ b ≤ 0.8, 0 ≤ c ≤ 0.8, 0 ≤ d ≤ 0.7, 0 ≤ e ≤ 0.7, and 0 ≤ f ≤ 0.4. It is even more preferable that 0 ≤ a1 ≤ 0.8, 0 ≤ a2 ≤ 0.8, 0.1 ≤ a1 + a2 ≤ 0.8, 0 ≤ b ≤ 0.75, 0 ≤ c ≤ 0.75, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.6, and 0 ≤ f ≤ 0.3. In addition, when repeating unit f is at least one selected from repeating units f1 to f5, f = f1 + f2 + f3 + f4 + f5. Also, a1 + a2 + b + c + d + e + f = 1.0.

[0399] On the other hand, for the base polymer for a negative resist material, acid-labile groups are not necessary. Examples of such base polymers include those containing repeating unit b, and optionally further containing repeating units c, d, e, and / or f. The content ratios of these repeating units should be 0 < b ≤ 1.0, 0 ≤ c ≤ 0.9, 0 ≤ d ≤ 0.8, 0 ≤ e ≤ 0.8, and 0 ≤ f ≤ 0.5. It is more preferable that 0.2 ≤ b ≤ 1.0, 0 ≤ c ≤ 0.8, 0 ≤ d ≤ 0.7, 0 ≤ e ≤ 0.7, and 0 ≤ f ≤ 0.4. It is even more preferable that 0.3 ≤ b ≤ 1.0, 0 ≤ c ≤ 0.75, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.6, and 0 ≤ f ≤ 0.3. In addition, when repeating unit f is at least one selected from repeating units f1 to f5, f = f1 + f2 + f3 + f4 + f5. Also, b + c + d + e + f = 1.0.

[0400] Examples of the method for synthesizing the aforementioned base polymer include, for example, a method of adding a radical polymerization initiator and heating monomers providing the aforementioned repeating units in an organic solvent to carry out polymerization.

[0401] Specific examples of the organic solvent used in the polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, etc. Specific examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, etc. The temperature during polymerization should be 50 to 80 °C. The reaction time should be 2 to 100 hours, and more preferably 5 to 20 hours.

[0402] When copolymerizing a hydroxyl group-containing monomer, the hydroxyl group can be substituted with an acetal group such as ethoxyethoxy that is easily deprotected by an acid prior to polymerization, and deprotection can be carried out using a weak acid and water after polymerization. It is also possible to substitute with an acetyl group, a formyl group, a trimethylacetyl group, etc. in advance, and carry out base hydrolysis after polymerization.

[0403] When copolymerizing hydroxystyrene and hydroxyvinylnaphthalene, hydroxystyrene and hydroxyvinylnaphthalene can also be replaced with acetoxystyrene and acetoxyvinylnaphthalene, and after polymerization, the acetoxy group can be deprotected by the aforementioned base hydrolysis to become hydroxystyrene and hydroxyvinylnaphthalene.

[0404] As the base for base hydrolysis, ammonia water, triethylamine, etc. can be used. Also, the reaction temperature should preferably be -20 to 100 °C, more preferably 0 to 60 °C. The reaction time should preferably be 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0405] The polystyrene-reduced weight average molecular weight (Mw) of the aforementioned base polymer determined by gel permeation chromatography (GPC) using THF as a solvent should preferably be 1000 to 500000, more preferably 2000 to 30000. If Mw is within the aforementioned range, the heat resistance of the resist film and the solubility in an alkaline developer are good.

[0406] In addition, when the molecular weight distribution (Mw / Mn) in the aforementioned base polymer is wide, since there will be low molecular weight and high molecular weight polymers, there is a concern that foreign substances will be observed in the pattern and the shape of the pattern will deteriorate after exposure. As the pattern is regularly miniaturized, the influence of Mw and Mw / Mn also easily becomes larger. Therefore, in order to obtain a resist material that can be ideally used for fine pattern sizes, the Mw / Mn of the aforementioned base polymer should preferably be 1.0 to 2.0, and a narrow dispersion of 1.0 to 1.5 is particularly good.

[0407] The aforementioned base polymer can also contain two or more kinds of polymers with different composition ratios, Mw, and Mw / Mn.

[0408] [Organic solvent]

[0409] The resist material of the present invention may also contain an organic solvent. The foregoing organic solvent is not particularly limited as long as it can dissolve the foregoing components and the following components. Specific examples of the foregoing organic solvent include: ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, 2-heptanone, etc. described in paragraphs

[0144] to

[0145] of Japanese Patent Laid-Open No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, etc.; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, etc.; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol monoterbutyl ether acetate, etc.; lactones such as γ-butyrolactone, etc.

[0410] In the resist material of the present invention, the content of the foregoing organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, based on 100 parts by mass of the base polymer. The foregoing organic solvent may be used alone or in combination of two or more.

[0411] [Quencher]

[0412] The resist material of the present invention may also contain a quencher. In addition, a quencher means a compound that can prevent the acid generated from the acid generator in the resist material from diffusing to the unexposed portion by capturing the acid.

[0413] Examples of the foregoing quencher include known types of basic compounds. Specific examples of known types of basic compounds include: primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, urethanes, etc. Particularly preferably, they are primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Laid-Open No. 2008-111103, amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, a sulfonate bond, or compounds having a urethane bond described in Japanese Patent No. 3790649, etc. By adding such a basic compound, for example, the diffusion rate of the acid in the resist film can be further suppressed, or the shape can be corrected.

[0414] Further, examples of the quenching agent include sulfonium salts, oxonium salts, ammonium salts, etc. of sulfonic acids, carboxylic acids or fluorinated alkoxides in which the α-position is not fluorinated, as described in Japanese Patent Application Laid-Open No. 2008-158339. Sulfonic acids, imidic acids or methylated acids in which the α-position is fluorinated are necessary for deprotecting the acid labile group of the carboxylic acid ester, and by salt exchange with the above-mentioned onium salts, sulfonic acids, carboxylic acids or fluorinated alcohols in which the α-position is not fluorinated are released. Sulfonic acids, carboxylic acids and fluorinated alcohols in which the α-position is not fluorinated do not cause a deprotection reaction, so they function as quenching agents.

[0415] Specific examples of such a quenching agent include, for example, a compound represented by the following formula (4) (onium salt of a sulfonic acid in which the α-position is not fluorinated), a compound represented by the following formula (5) (onium salt of a carboxylic acid), and a compound represented by the following formula (6) (onium salt of an alkoxide).

[0416] [Chemical Formula 137]

[0417]

[0418] In formula (4), R 101 is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom, provided that the hydrogen atom at the α-carbon atom bonded to the sulfo group is not substituted with a fluorine atom or a fluoroalkyl group.

[0419] R 101 The hydrocarbon group having 1 to 40 carbon atoms represented may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl; cyclic saturated hydrocarbon groups having 3 to 40 carbon atoms such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6 decyl, adamantyl, adamantylmethyl; alkenyl groups having 2 to 40 carbon atoms such as vinyl, allyl, propenyl, butenyl, hexenyl; cyclic unsaturated aliphatic hydrocarbon groups having 3 to 40 carbon atoms such as cyclohexenyl; aryl groups having 6 to 40 carbon atoms such as phenyl, naphthyl, alkylphenyl (2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 4-n-butylphenyl, etc.), di- or tri-alkylphenyl (2,4-dimethylphenyl, 2,4,6-triisopropylphenyl, etc.), alkylnaphthyl (methylnaphthyl, ethylnaphthyl, etc.), dialkylnaphthyl (dimethylnaphthyl, diethylnaphthyl, etc.); aralkyl groups having 7 to 40 carbon atoms such as benzyl, 1-phenylethyl, 2-phenylethyl, etc.

[0420] Further, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, it may also contain a hydroxyl group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Specific examples of the heteroatom-containing hydrocarbon group include: heteroaryl groups such as thienyl; alkoxyphenyl groups such as 4-hydroxyphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 4-tert-butoxyphenyl, 3-tert-butoxyphenyl; alkoxynaphthyl groups such as methoxynaphthyl, ethoxynaphthyl, n-propoxynaphthyl, n-butoxynaphthyl; dialkoxynaphthyl groups such as dimethoxynaphthyl, diethoxynaphthyl; aryl oxoalkyl groups such as 2-aryl-2-oxoethyl groups such as 2-phenyl-2-oxoethyl, 2-(1-naphthyl)-2-oxoethyl, 2-(2-naphthyl)-2-oxoethyl, etc.

[0421] In formula (5), R 102 is a hydrocarbon group having 1 to 40 carbon atoms that may also contain a heteroatom. Specific examples of the hydrocarbon group represented by R 102 may be listed and exemplified as the same examples as those of the hydrocarbon group represented by R 101 In addition, other specific examples include: fluoroalkyl groups such as trifluoromethyl, trifluoroethyl, 2,2,2-trifluoro-1-methyl-1-hydroxyethyl, 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl; fluoroaryl groups such as pentafluorophenyl, 4-trifluoromethylphenyl, etc.

[0422] In formula (6), R 103 is a saturated hydrocarbon group having 1 to 8 carbon atoms having at least 3 fluorine atoms or an aryl group having 6 to 10 carbon atoms having at least 3 fluorine atoms, and may also contain a nitro group.

[0423] In formulas (4), (5) and (6), Mq + is an onium cation. The aforementioned onium cation is preferably a sulfonium cation, an iodonium cation or an ammonium cation, and more preferably a sulfonium cation. Specific examples of the aforementioned sulfonium cation may be listed as the same examples as those of the sulfonium cation exemplified in the description of formula (1) and represented by M +

[0424] A sulfonium salt of a benzenecarboxylic acid containing an iodobenzene ring represented by the following formula (7) can also be desirably used as the quencher.

[0425] [Chemical formula 138]

[0426]

[0427] ​In formula (7), x is an integer from 1 to 5, y is an integer from 0 to 3, and z is an integer from 1 to 3.

[0428] In formula (7), R 111 is a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbon group having 1 to 6 carbon atoms, a saturated hydrocarbon group oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon group carbonyl oxy group having 2 to 6 carbon atoms or a saturated hydrocarbon group sulfonyl oxy group having 1 to 4 carbon atoms, or -N(R 111A )-C(=O)-R 111B or -N(R 111A )-C(=O)-O-R 111B . R 111A is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. R 111B is a saturated hydrocarbon group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 8 carbon atoms. When y and / or z is 2 or more, each R 111 may be the same or different from each other.

[0429] In formula (7), L 1 is a single bond or a (z + 1)-valent linking group having 1 to 20 carbon atoms, and may also contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxyl group, and a carboxyl group. The aforementioned saturated hydrocarbon group, saturated hydrocarbon group oxy group, saturated hydrocarbon group carbonyl oxy group, and saturated hydrocarbon group sulfonyl oxy group may be linear, branched, or cyclic.

[0430] In formula (7), R 112 , R 113 and R 114 are each independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof may include the same examples as those of the hydrocarbon groups represented as R 3 to R 7 in the descriptions of formulas (2) and (3).

[0431] Specific examples of the compound represented by formula (7) may include those described in JP-A-2017-219836 and JP-A-2021-91666.

[0432] Other examples of the aforementioned quencher may include the polymer-type quencher described in JP-A-2008-239918. This improves the rectangularity of the resist pattern by aligning on the surface of the resist film. The polymer-type quencher also has the effect of preventing pattern film loss and pattern doming when using a protective film for immersion exposure.

[0433] In addition, sulfonium salts of the betaine type described in Japanese Patent No. 6848776 and Japanese Unexamined Patent Application Publication No. 2020-37544, fluorine atom-free methylated acids described in Japanese Unexamined Patent Application Publication No. 2020-55797, sulfonium salts of sulfonamides described in Japanese Patent No. 5807552, sulfonium salts of iodine atom-containing sulfonamides described in Japanese Unexamined Patent Application Publication No. 2019-211751, and acid generators that generate phenol, halogen, and carbonic acid can be used as quenchers.

[0434] When the resist material of the present invention contains the aforementioned quencher, its content is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, relative to 100 parts by mass of the base polymer. The aforementioned quencher can be used alone or in combination of two or more.

[0435] [Other Components]

[0436] In addition to containing the aforementioned components, an acid generator other than the salt represented by the formula (1) (hereinafter referred to as other acid generator), a surfactant, a dissolution inhibitor, a crosslinking agent, a water repellency improver, acetylene alcohols, etc. can also be contained.

[0437] Examples of the aforementioned other acid generators include compounds that generate an acid upon exposure to actinic rays or radiation (photoacid generators). Any compound that generates an acid upon irradiation with high-energy rays can be used as the component of the photoacid generator, and an acid generator that generates sulfonic acid, imidic acid, or methylated acid is preferred. Specific examples of ideal photoacid generators include sulfonium salts, iodonium salts, sulfonyl diazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate type acid generators. Specific examples of the aforementioned acid generators include those described in paragraphs

[0122] to

[0142] of Japanese Unexamined Patent Application Publication No. 2008-111103, Japanese Unexamined Patent Application Publication No. 2018-5224, and Japanese Unexamined Patent Application Publication No. 2018-25789. When the resist material of the present invention contains other acid generators, its content is preferably 0 to 200 parts by mass, more preferably 0.1 to 100 parts by mass, relative to 100 parts by mass of the base polymer.

[0438] Specific examples of the aforementioned surfactant include those described in paragraphs

[0165] to

[0166] of Japanese Unexamined Patent Application Publication No. 2008-111103. By adding a surfactant, the coatability of the resist material can be further improved or controlled. When the resist material of the present invention contains a surfactant, its content is preferably 0.0001 to 10 parts by mass relative to 100 parts by mass of the base polymer. The aforementioned surfactant can be used alone or in combination of two or more.

[0439] When the resist material of the present invention is positive type, by blending a dissolution inhibitor, the dissolution rate difference between the exposed portion and the unexposed portion can be further enlarged, and the resolution can be further improved. Specific examples of the foregoing dissolution inhibitor include: a compound in which the hydrogen atom of the phenolic hydroxyl group in a compound having a molecular weight of preferably 100 to 1000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule is substituted by an acid-labile group in a proportion of 0 to 100 mol% as a whole, or a compound in which the hydrogen atom of the carboxyl group in a compound containing a carboxyl group in the molecule is substituted by an acid-labile group in a proportion of preferably 50 to 100 mol% on average as a whole. Specific examples include: compounds in which the hydrogen atoms of the hydroxyl group and carboxyl group of bisphenol A, triphenol, phenolphthalein, cresol novolak resin, naphthoic acid, adamantane carboxylic acid, and cholic acid are substituted by acid-labile groups, etc., for example, those described in paragraphs

[0155] to

[0178] of Japanese Patent Laid-Open No. 2008-122932.

[0440] When the resist material of the present invention is positive type and contains the foregoing dissolution inhibitor, its content is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, based on 100 parts by mass of the base polymer. The foregoing dissolution inhibitor can be used alone or in combination of two or more.

[0441] On the other hand, when the resist material of the present invention is negative type, by adding a crosslinking agent to reduce the dissolution rate of the exposed portion, a negative pattern can be obtained thereby. Specific examples of the foregoing crosslinking agent include: epoxy compounds substituted by at least one group selected from hydroxymethyl, alkoxymethyl, and acyloxymethyl, melamine compounds, guanamine compounds, glycoluril compounds or urea compounds, isocyanate compounds, azide compounds, compounds containing double bonds such as alkenyloxy groups, etc. They can be used in the form of additives or introduced into the polymer side chain as pendant groups. Also, compounds containing hydroxyl groups can be used as crosslinking agents.

[0442] Specific examples of the foregoing epoxy compounds include: tris(2,3-epoxypropyl) isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triethylolethane triglycidyl ether, etc.

[0443] Specific examples of the foregoing melamine compounds include: hexahydroxymethyl melamine, hexamethoxymethyl melamine, compounds or mixtures in which 1 to 6 hydroxymethyl groups in hexahydroxymethyl melamine are methoxymethylated, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, compounds or mixtures in which 1 to 6 of the hydroxymethyl groups in hexahydroxymethyl melamine are acyloxymethylated, etc.

[0444] Specific examples of the guanylamine compound include: tetramethylol guanylamine, tetramethoxymethyl guanylamine, a compound or mixture thereof in which 1 to 4 hydroxymethyl groups in tetramethylol guanylamine are methoxymethylated, tetramethoxyethyl guanylamine, tetraacyloxy guanylamine, a compound or mixture thereof in which 1 to 4 hydroxymethyl groups in tetramethylol guanylamine are acyloxymethylated, and the like.

[0445] Specific examples of the glycoluril compound include: tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, a compound or mixture thereof in which 1 to 4 hydroxymethyl groups in tetramethylol glycoluril are methoxymethylated, a compound or mixture thereof in which 1 to 4 hydroxymethyl groups in tetramethylol glycoluril are acyloxymethylated, and the like. Specific examples of the urea compound include: tetramethylol urea, tetramethoxymethyl urea, a compound or mixture thereof in which 1 to 4 hydroxymethyl groups in tetramethylol urea are methoxymethylated, tetramethoxyethyl urea, and the like.

[0446] Specific examples of the isocyanate compound include: tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, and the like.

[0447] Specific examples of the azide compound include: 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylenebisazide, 4,4'-oxybisazide, and the like.

[0448] Specific examples of the compound containing an alkenyloxy group include: ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, trimethylolpropane trivinyl ether, and the like.

[0449] When the resist material of the present invention is negative and contains the aforementioned crosslinking agent, its content is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, based on 100 parts by mass of the base polymer. The aforementioned crosslinking agent can be used alone or in combination of two or more.

[0450] The aforementioned water repellency improver is one that improves the water repellency of the resist film surface and can be used in immersion lithography without using a top coat. The aforementioned water repellency improver is preferably a polymer containing a fluorinated alkyl group, a polymer containing 1,1,1,3,3,3 - hexafluoro - 2 - propanol residues with a specific structure, etc., and is preferably an example exemplified in Japanese Patent Laid - Open No. 2007 - 297590, Japanese Patent Laid - Open No. 2008 - 111103, etc. The aforementioned water repellency improver must be soluble in an alkali developer and an organic solvent developer. The aforementioned specific water repellency improver having 1,1,1,3,3,3 - hexafluoro - 2 - propanol residues has good solubility in the developer. Regarding the water repellency improver, a polymer containing repeating units of amino group and amine salt has a high effect of preventing the evaporation of acid during PEB and preventing the opening defect of the hole pattern after development. When the resist material of the present invention contains the aforementioned water repellency improver, its content is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the base polymer. The aforementioned water repellency improver can be used alone or in combination of two or more kinds.

[0451] Specific examples of the aforementioned acetylene alcohols can be those described in paragraphs

[0179] to

[0182] of Japanese Patent Laid - Open No. 2008 - 122932. When the resist material of the present invention contains the aforementioned acetylene alcohols, its content is preferably 0 to 5 parts by mass relative to 100 parts by mass of the base polymer. The aforementioned acetylene alcohols can be used alone or in combination of two or more kinds.

[0452] [Pattern formation method]

[0453] When the resist material of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be used. For example, regarding the pattern formation method, a method including the following steps can be cited: forming a resist film on a substrate using the aforementioned resist material, exposing the aforementioned resist film to high - energy rays, and developing the aforementioned exposed resist film using a developer.

[0454] First, the resist material of the present invention is coated on a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor blade coating, etc., so that the coating film thickness becomes 0.01 to 2 μm. It is pre - baked on a hot plate at 60 to 150 °C for 10 seconds to 30 minutes, and more preferably at 80 to 120 °C for 30 seconds to 20 minutes to form a resist film.

[0455] Then, the aforementioned resist film is exposed using high-energy rays. Specific examples of the aforementioned high-energy rays include: ultraviolet rays, far ultraviolet rays, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer lasers, γ-rays, synchrotron radiation, etc. When the aforementioned high-energy rays are ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, γ-rays, synchrotron radiation, etc., a mask for forming a target pattern is used directly or, and the exposure dose should be about 1 to 200 mJ / cm 2 and more preferably about 10 to 100 mJ / cm 2 for irradiation. When the high-energy ray is EB, the exposure dose should be about 0.1 to 300 μC / cm 2 and more preferably about 0.5 to 200 μC / cm 2 for direct drawing or using a mask for forming a target pattern. In addition, the resist material of the present invention is particularly suitable for fine patterning by KrF excimer lasers, ArF excimer lasers, EB, EUV, X-rays, soft X-rays, γ-rays, synchrotron radiation in high-energy rays, and is particularly suitable for fine patterning by EB or EUV.

[0456] After exposure, PEB with a temperature of preferably 30 to 150 °C, a time of 10 seconds to 30 minutes, and more preferably 50 to 120 °C, 30 seconds to 20 minutes can also be performed on a hot plate or in an oven, or it may not be performed.

[0457] After exposure or PEB, the resist film is developed by using a developer containing an aqueous alkali solution of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. with a concentration of preferably 0.1 to 10% by mass and ideally 2 to 5% by mass for 3 seconds to 3 minutes and preferably 5 seconds to 2 minutes using common methods such as dip method, puddle method, spray method, etc., and the target pattern will be formed. In the case of a positive resist material, the irradiated part will dissolve in the developer, and the unexposed part will not dissolve, and a positive pattern of the target will be formed on the substrate. In the case of a negative resist material, it is the opposite of the case of the positive resist material, the irradiated part will not dissolve in the developer, and the unexposed part will dissolve.

[0458] A positive resist material containing a base polymer having an acid-labile group can also be used, and negative patterns can be obtained by developing with an organic solvent. Specific examples of the developer used at this time include: 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, butenyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents can be used alone or in combination of two or more.

[0459] Rinsing is carried out at the end of development. The rinsing liquid is preferably a solvent that is miscible with the developer and does not dissolve the resist film. Such a solvent can ideally be an alcohol having 3 to 10 carbon atoms, an ether compound having 8 to 12 carbon atoms, an alkane, alkene, alkyne, or aromatic solvent having 6 to 12 carbon atoms.

[0460] Specific examples of the alcohol having 3 to 10 carbon atoms include: n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentanol, neopentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, etc.

[0461] Specific examples of the ether compound having 8 to 12 carbon atoms include: di-n-butyl ether, diisobutyl ether, di(sec-butyl) ether, di-n-pentyl ether, diisopentyl ether, di(sec-pentyl) ether, di(tert-pentyl) ether, di-n-hexyl ether, etc.

[0462] Specific examples of the alkanes having 6 to 12 carbon atoms include: hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Specific examples of the alkenes having 6 to 12 carbon atoms include: hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Specific examples of the alkynes having 6 to 12 carbon atoms include: hexyne, heptyne, octyne, etc.

[0463] Specific examples of the aromatic solvents include: toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, etc.

[0464] By performing rinsing, the collapse of the resist pattern and the occurrence of defects can be reduced. Also, rinsing is not necessary, and by not performing rinsing, the amount of solvent used can be reduced.

[0465] The developed hole pattern and groove pattern can also be shrunk using heat flow, RELACS technology, or DSA technology. A shrinkage agent is coated on the hole pattern, and due to the diffusion of the acid catalyst from the resist film during baking, crosslinking of the shrinkage agent occurs on the surface of the resist film, and the shrinkage agent adheres to the sidewalls of the hole pattern. The baking temperature should be 70 to 180 °C, more preferably 80 to 170 °C, and the baking time should be 10 to 300 seconds to remove the excess shrinkage agent and shrink the hole pattern.

[0466] Examples

[0467] Hereinafter, synthesis examples, examples, and comparative examples are illustrated to specifically describe the present invention, but the present invention is not limited to the following examples.

[0468] The structures of the bis-onium salts PAG-PDQ-1 to PAG-PDQ-10 used as an acid generator and quencher in the resist material are shown below.

[0469] [Chemical formula 139]

[0470]

[0471] [Chemical formula 140]

[0472]

[0473] [Chemical formula 141]

[0474]

[0475] [Chemical formula 142]

[0476]

[0477] [Chemical formula 143]

[0478]

[0479] [Synthesis Example] Synthesis of Base Polymers (Polymers P-1 to P-5)

[0480] The monomers were combined and copolymerization was carried out in THF as a solvent. The resulting mixture was poured into methanol, and the precipitated solid was washed with hexane, separated, and dried to obtain base polymers (Polymers P-1 to P-5) having the following compositions. The compositions of the obtained base polymers were confirmed by 1 1H-NMR, and Mw and Mw / Mn were confirmed by GPC (solvent: THF, standard: polystyrene).

[0481] [Chemical Formula 144]

[0482]

[0483] [Examples 1 to 17, Comparative Examples 1 to 3] Preparation and Evaluation of Resist Materials

[0484] (1) Preparation of Resist Materials

[0485] A solution prepared by dissolving each component in the composition shown in Table 1 was filtered through a 0.2-μm filter to prepare a resist material.

[0486] In Table 1, each component is as described below.

[0487] Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0488] EL (ethyl lactate)

[0489] DAA (diacetone alcohol)

[0490] Comparative acid generator and quencher: cPAG-PDQ-1

[0491] [Chemical Formula 145]

[0492]

[0493] Comparative acid generator: cPAG-1

[0494] [Chemical Formula 146]

[0495]

[0496] Blended acid generators: bPAG-1, bPAG-2

[0497] [Chemical Formula 147]

[0498]

[0499] Blended quencher: bPDQ-1

[0500] [Chemical formula 148]

[0501]

[0502] Comparative quencher: cPDQ-1

[0503] [Chemical formula 149]

[0504]

[0505] (2) EUV lithography evaluation

[0506] Each resist material shown in Table 1 was spin-coated on a Si substrate on which a spin-on hard mask SHB-A940 containing silicon (silicon content: 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and prebaked at 105 °C for 60 seconds using a hot plate to obtain a resist film with a film thickness of 40 nm. The aforementioned resist film was exposed using an EUV scanning exposure machine NXE3400 (NA 0.33, σ 0.9 / 0.7, dipole illumination) manufactured by ASML Corporation, and PEB was performed at the temperature described in Table 1 for 60 seconds on a hot plate, and then developed with a 2.38% by mass TMAH aqueous solution for 30 seconds to form lines and spaces with a pitch of 32 nm and a line width of 16 nm. Examples 1 to 16 and Comparative Examples 1 and 2 are positive resist materials, and Example 17 and Comparative Example 3 are negative resist materials.

[0507] Using a length measurement SEM (CG6300) manufactured by Hitachi High-Tech Corporation, the exposure dose at which line patterns were formed with a size of 16 nm ± 1.6 nm was determined, and the LWR of the line patterns at this exposure dose was measured. The results are shown in Table 1.

[0508] [Table 1]

[0509]

[0510]

[0511] From the results shown in Table 1, it can be seen that the resist material of the present invention containing a divalent anion having a benzene oxide anion structure substituted with an iodine atom and a fluorosulfonic acid anion structure of an aromatic ring bonded to the benzene oxide anion structure, and an onium cation, has high sensitivity and good LWR.

Claims

1. A resist material containing: A bis - onium salt containing a divalent anion having a fluorosulfonic acid anion structure with a phenoxide anion structure substituted by an iodine atom and an aromatic ring bonded to the phenoxide anion structure, and an onium cation.

2. The resist material according to claim 1, wherein The bis - onium salt is represented by the following formula (1); In the formula, m is an integer from 1 to 4; n is an integer from 0 to 3; provided that 1 ≤ m + n ≤ 4; p is 0 or 1; X 1 and X 2 are each independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond; R 1 is a hydrocarbon group having 1 to 10 carbon atoms, a halogen atom other than an iodine atom, a nitro group or a cyano group, and the hydrocarbon group may also have at least one selected from halogen atoms, oxygen atoms, sulfur atoms and nitrogen atoms; R 2 is a single bond or an alkylene group having 1 to 40 carbon atoms, and the alkylene group may also contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom; Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group; provided that when p is 0, at least one of Rf 3 and Rf 4 is a fluorine atom or a trifluoromethyl group, and when p is 1, at least one of Rf 1 ~Rf 4 is a fluorine atom or a trifluoromethyl group; further, Rf 1 and Rf 2 may also combine to form a carbonyl group; M + is a sulfonium cation or an iodonium cation.

3. The resist material according to claim 1, further containing a base polymer.

4. The resist material according to claim 3, wherein, The base polymer contains a repeating unit represented by the following formula (a1) or (a2); In the formula, R A are each independently a hydrogen atom or a methyl group; Y 1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one selected from an ester bond, an ether bond, and a lactone ring, and the phenylene group, naphthylene group, and linking group may also have at least one selected from a hydroxyl group, a saturated hydrocarbon group oxy group having 1 to 8 carbon atoms, and a saturated hydrocarbon group carbonyl oxy group having 2 to 8 carbon atoms; Y 2 is a single bond or an ester bond; Y 3 is a single bond, an ether bond or an ester bond; R 11 and R 12 are each independently acid-labile groups; R 13 is a saturated hydrocarbon group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbon group carbonyl having 2 to 5 carbon atoms, a cyano group or a saturated hydrocarbon group oxycarbonyl having 2 to 5 carbon atoms; R 14 is a single bond or an alkanediyl group with 1 to 6 carbon atoms, and the alkanediyl group may also contain an ether bond or an ester bond; a is an integer from 0 to 4.

5. The resist material according to claim 4, which is a chemically amplified positive - type resist material.

6. The resist material according to claim 3, wherein, The base polymer does not contain acid - labile groups.

7. The resist material according to claim 6, which is a chemically amplified negative - type resist material.

8. The resist material according to claim 1, further containing an organic solvent.

9. The resist material according to claim 1, further containing a quencher.

10. The resist material according to claim 1, further containing an acid generator.

11. The resist material according to claim 1, further containing a surfactant.

12. A pattern forming method comprising the following steps: Forming a resist film on a substrate using the resist material according to any one of claims 1 to 11, Exposing the resist film with high - energy rays, and Developing the exposed resist film using a developer.

13. The pattern forming method according to claim 12, wherein, The high - energy rays are an ArF excimer laser with a wavelength of 193 nm, a KrF excimer laser with a wavelength of 248 nm, an electron beam, or an extreme ultraviolet ray with a wavelength of 3 to 15 nm.

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