Chemically Amplified Resist Composition and Pattern Forming Method

Abstract

To provide a chemically amplified resist composition that exhibits a high sensitivity and improved LWR and CDU in photolithography using high energy rays, and a patterning process using the same.SOLUTION: Provided is a chemically amplified resist composition comprising (A) a polymer P comprising a repeat unit having an acid labile group containing a predetermined fluorinated aromatic ring, a repeat unit having a phenolic hydroxy group, and a repeat unit adapted to generate an acid by predetermined exposure operation, (B) an onium salt type quencher, and (C) a solvent.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a chemically amplified resist composition and a pattern forming method using the resist composition.

Background Art

[0002] In recent years, with the higher integration of integrated circuits, finer pattern formation has been required, and chemically amplified resists catalyzed by acid alone are used for processing patterns of 0.2 μm or less. Further, high-energy rays such as ultraviolet rays, far ultraviolet rays, and electron beams (EB) are used as exposure light sources at this time. In particular, electron beam lithography, which is used as an ultrafine processing technology, is also indispensable as a method for processing a photomask blank when manufacturing a photomask for semiconductor manufacturing.

[0003] Polymers having a large amount of aromatic skeletons having acidic side chains, such as polyhydroxystyrene, have been usefully used as materials for resists for KrF excimer lasers. However, since they show a large absorption for light in the vicinity of a wavelength of 200 nm, they have not been used as materials for resists for ArF excimer lasers. However, they are important materials in terms of obtaining high etching resistance as resist compositions for EB lithography and resist compositions for extreme ultraviolet (EUV) lithography, which are promising technologies for forming patterns smaller than the processing limit by ArF excimer lasers.

[0004] As base polymers for positive EB lithography resist compositions and EUV lithography resist compositions, materials are mainly used that, by using the acid generated from a photoacid generator upon irradiation with high-energy rays as a catalyst, deprotect an acid-decomposable protecting group that masks the acidic functional group of the phenolic side chain of the base polymer, and solubilize it in an alkaline developer. Further, as the acid-decomposable protecting group, a tertiary alkyl group, a tert-butoxycarbonyl group, an acetal group, etc. have mainly been used. Here, when using a protecting group with a relatively small activation energy required for deprotection, such as an acetal group, although there is an advantage that a highly sensitive resist film can be obtained, if the suppression of the diffusion of the generated acid is not sufficient, a deprotection reaction occurs even in the unexposed portion of the resist film, leading to problems such as deterioration of line width roughness (LWR) and a decrease in pattern dimension uniformity (CDU).

[0005] The control of sensitivity and pattern profile has been improved in various ways by the selection and combination of materials used in the resist composition, process conditions, etc. One of the improvements is the problem of acid diffusion that significantly affects the resolution of chemically amplified resist compositions. Since this problem of acid diffusion significantly affects sensitivity and resolution, many studies have been conducted.

[0006] Also, in an attempt to improve sensitivity, attempts have been made to introduce multiple bonds or aromatic rings into the acid-labile groups of the base polymer of the resist composition. Although some performance improvement can be seen by the introduction of these substituents, satisfactory results have not yet been obtained (Patent Documents 1 to 8).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Summary of the Invention

Problems to be Solved by the Invention

[0008] In a chemically amplified resist composition using an acid as a catalyst, it is desired to develop a chemically amplified resist composition that can achieve further high sensitivity and improve the LWR of line patterns and the CDU of hole patterns.

[0009] The present invention has been made in view of the above circumstances, and an object thereof is to provide a chemically amplified resist composition that is highly sensitive and has improved LWR and CDU in photolithography using high-energy rays, particularly EB lithography and EUV lithography, and a patterning method using the same.

Means for Solving the Problems

[0010] As a result of intensive studies to achieve the above object, the present inventors have found that by using a polymer containing a repeating unit having a fluorine atom aromatic ring as an acid-labile group, a repeating unit having a phenolic hydroxy group, and a repeating unit that generates an acid upon exposure, an onium salt type quencher, and a solvent, a pattern formation with high sensitivity, high contrast, excellent resolution, and a wide process margin excellent in the LWR of line patterns and the CDU of hole patterns becomes possible, and the present invention has been completed.

[0011] That is, the present invention provides the following chemically amplified resist composition and a patterning method. 1. (A) A polymer P that contains a repeating unit having an acid-labile group containing a fluorine atom-containing aromatic ring represented by the following formula (A1), a repeating unit having a phenolic hydroxy group, and a repeating unit that generates an acid upon exposure represented by any one of the following formulas (C1) to (C4), and whose solubility in a developer changes by the action of an acid. (B) An onium salt type quencher, and (C) A solvent A chemically amplified resist composition containing the same. [Chemical formula] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z A is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-Z A1 -. Z A1 is a hydroxy group, an ether bond, an ester bond, or an aliphatic hydrocarbylene group having 1 to 20 carbon atoms that may contain a lactone ring, or a phenylene group or a naphthylene group. * represents a bond to a carbon atom in the main chain. R B and R C are each independently a hydrocarbyl group having 1 to 10 carbon atoms that may contain a hetero atom, and R B and R C may be bonded to each other to form a ring together with the carbon atom to which they are bonded. R 1 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms. R 2 are each independently a hydrocarbyl group having 1 to 10 carbon atoms that may contain a hetero atom. n1 is an integer of 1 or 2. n2 is an integer of 0 to 5. n3 is an integer of 0 to 2.) [Chemical formula] (wherein R A is the same as described above. Z 1 is a single bond or a phenylene group. Z 2 is *-C(=O)-O-Z 21 -, *-C(=O)-NH-Z 21 - or *-O-Z 21 -. Z 21 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 3 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-Z 31 -. Z 31 is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond, or a lactone ring, or a phenylene group or a naphthylene group. Z 4 is a single bond or *-Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms, which may contain a hetero atom. 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, *-C(=O)-O-Z 51 -, *-C(=O)-N(H)-Z 51 - or *-O-Z 51 -. Z 51 is an aliphatic hydrocarbylene 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 contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. * represents a bond to a carbon atom in the main chain. R 21 and R 22 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hetero atom. Also, R 21and R 22 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonic acid ester bond, a carbonate bond or a carbamate bond. Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. Rf 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. However, all Rf 5 and Rf 6 will not simultaneously become hydrogen atoms. M - is a non-nucleophilic counter ion. A + is an onium cation. c is an integer from 0 to 3.) 2. A chemically amplified resist composition in which the repeating unit represented by the formula (A1) is the one represented by the following formula (A2).

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Effects of the Invention

[0012] By using the chemically amplified resist composition of the present invention, it is possible to construct a resist pattern having high sensitivity, improved LWR and CDU, high contrast, excellent resolution, and a wide process margin.

Modes for Carrying Out the Invention

[0013] [Chemically Amplified Resist Composition] The chemically amplified resist composition of the present invention contains (A) a polymer P containing a repeating unit having an acid-labile group containing a fluorine atom-containing aromatic ring, a repeating unit having a phenolic hydroxy group, and a repeating unit that generates an acid upon exposure, (B) an onium salt type quencher, and (C) a solvent.

[0014] [(A) Polymer P] The polymer P of component (A) functions as a base polymer and contains a repeating unit having an acid-labile group containing a fluorine atom-containing aromatic ring (hereinafter also referred to as repeating unit A). The repeating unit A is represented by the following formula (A1).

Chemical formula

[0015] In formula (A1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0016] In formula (A1), Z A is a single bond, a phenylene group, a naphthylene group or *-C(=O)-O-Z A1 -. Z A1 is a hydroxyl group, an ether bond, an ester bond, an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a lactone ring, or a phenylene group or a naphthylene group. * represents a bond to a carbon atom in the main chain.

[0017] Z A1The aliphatic hydrocarbylene group represented by may be linear, branched or cyclic. Specific examples thereof include alkanediyl groups having 1 to 20 carbon atoms such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, propane-2,2-diyl group, butane-1,1-diyl group, butane-1,2-diyl group, butane-1,3-diyl group, butane-2,3-diyl group, butane-1,4-diyl group, 1,1-dimethylethane-1,2-diyl group, pentane-1,5-diyl group, 2-methylbutane-1,2-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group; cycloalkanediyl groups having 3 to 20 carbon atoms such as cyclopropanediyl group, cyclobutane-1,1-diyl group, cyclobutanediyl group, cyclopentanediyl group, cyclohexanediyl group; polycyclic saturated hydrocarbylene groups having 4 to 20 carbon atoms such as adamantanediyl group, norbornanediyl group; and divalent groups obtained by combining these.

[0018] Z in formula (A1) A Examples of the structure in which is changed include, but are not limited to, those shown below. In the following formulas, R A is the same as described above, and the dashed line represents the bond to the carbon atom to which R B and R C are bonded.

Chemical formula

[0019]

Chemical formula

[0020]

Chemical formula

[0021]

Chemical formula

[0022] In formula (A1), R B and R C are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, 2-ethylhexyl group, n-octyl group; and cyclic saturated hydrocarbyl groups such as cyclopentyl group, cyclohexyl group, norbornyl group, tricyclodecanyl group, adamantyl group, etc.

[0023] Also, R B and R C may combine with each other to form a ring together with the carbon atom to which they are attached. Examples of the ring include cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, etc. Among these, cyclopentane ring and cyclohexane ring are preferred.

[0024] In formula (A1), R 1 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms or a fluorinated alkoxy group having 1 to 5 carbon atoms. Examples of the fluorinated alkyl group include fluoromethyl group, difluoromethyl group, trifluoromethyl group, 2,2,2-trifluoroethyl group, pentafluoroethyl group, pentafluoropropyl group, 1,1,1,3,3,3-hexafluoro-2-propyl group, nonafluorobutyl group, etc. Examples of the fluorinated alkoxy group include fluoromethoxy group, difluoromethoxy group, trifluoromethoxy group, 2,2,2-trifluoroethoxy group, pentafluoroethoxy group, pentafluoropropoxy group, 1,1,1,3,3,3-hexafluoro-2-propoxy group, nonafluorobutoxy group, etc. Among these, R 1It is preferably a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms, and more preferably a fluorine atom.

[0025] In formula (A1), R 2 is each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those exemplified as the hydrocarbyl groups represented by R B and R C .

[0026] In formula (A1), n1 is an integer of 1 or 2. n2 is an integer of 0 to 5, preferably 0 or 1. n3 is an integer of 0 to 2. When n3 is 0, it is a benzene ring; when n3 is 1, it is a naphthalene ring; when n3 is 2, it is an anthracene ring. From the viewpoint of solvent solubility, a benzene ring with n3 = 0 is preferred.

[0027] As the repeating unit A, those represented by the following formula (A2) are preferred.

Chemical formula

[0028] The monomer A1 that provides the repeating unit A can be produced, for example, according to the following scheme, but is not limited thereto.

Chemical formula

[0029] The first step is a step of reacting a ketone compound SM-2 that can be synthesized by a commercially available product or a known synthesis method with a Grignard reagent or an organolithium reagent prepared from a halide SM-1 to obtain a monomer precursor Pre-A1.)

[0030] The reaction can be carried out by a known organic synthesis method. Specifically, metallic magnesium or metallic lithium is suspended in an ether solvent such as tetrahydrofuran (THF) or diethyl ether, and a halide SM-1 diluted with the used solvent is added dropwise to prepare a Grignard reagent or an organolithium reagent. When preparing a Grignard reagent, especially when the halide SM-1 is a chloride, the reaction can be efficiently started by adding a small amount of 1,2-dibromoethane or iodine and then starting the dropwise addition of the halide SM-1. To the prepared Grignard reagent or organolithium reagent, a ketone compound SM-2 diluted with the used solvent is added dropwise. The reaction temperature is carried out from room temperature to about the boiling point of the used solvent. The reaction time is desirably determined by tracking the reaction by gas chromatography (GC) or silica gel thin-layer chromatography (TLC) to complete the reaction, but it is usually about 30 minutes to 2 hours. The monomer precursor Pre-A1 can be obtained from the reaction mixture by ordinary aqueous work-up. The obtained monomer precursor Pre-A1 can be purified according to conventional methods such as distillation, chromatography, and recrystallization if necessary.)

[0031] The second step is a step of introducing a polymerizable group through an ester bond to the tertiary alcohol Pre-A1 obtained in the first step to obtain a monomer A1.)

[0032] The reaction can be carried out by known organic synthesis methods. Specifically, the tertiary alcohol of Pre-A1 is dissolved in a solvent such as toluene, hexane, THF, acetonitrile, etc. in the presence of an organic base such as triethylamine or pyridine, and an acid halide such as methacrylic acid chloride or acrylic acid chloride is added dropwise to carry out the reaction. To accelerate the reaction rate, 4-dimethylaminopyridine may be added. The reaction temperature is carried out from 5°C to about the boiling point of the solvent used. The reaction time is desirably determined by tracking the reaction by GC or TLC until the reaction is complete, but it is usually about 1 to 24 hours. Monomer A1 can be obtained from the reaction mixture by ordinary aqueous work-up. The obtained monomer A1 can be purified according to conventional methods such as distillation, chromatography, recrystallization, etc. if necessary.

[0033] Examples of the repeating unit A represented by the formula (A1) include, but are not limited to, the following. In the following formulas, R A is the same as described above.

Chemical formula

[0034]

Chemical formula

[0035]

Chemical formula

[0036]

Chemical formula

[0037]

Chemical formula

[0038]

Chemical formula

[0039]

Chem.

[0040]

Chem.

[0041]

Chem.

[0042]

Chem.

[0043]

Chem.

[0044]

Chem.

[0045]

Chem.

[0046]

Chem.

[0047]

Chem.

[0048]

Chem.

[0049] [Chemistry]

[0050] [Chemistry]

[0051] [Chemistry]

[0052] [Chemistry]

[0053] [Chemistry]

[0054] [Chemistry]

[0055] [Chemistry]

[0056] [Chemistry]

[0057] [Chemistry]

[0058] [Chemistry]

[0059] [Chemistry]

[0060] [Chemistry]

[0061] [Chemistry]

[0062] [Chemistry]

[0063] [Chemistry]

[0064] [Chemistry]

[0065] The acid-labile group protected by carboxylic acid with tertiary benzyl alcohol has a very low activation energy for the deprotection reaction by acid catalyst compared to the acid-labile group of tertiary alkyl groups such as tert-butyl group, and the deprotection reaction proceeds even at a temperature of about 50°C. When a polymer having an acid-labile group with too low activation energy for the deprotection reaction is used as the base polymer, the post-exposure bake (PEB) temperature is too low, making it difficult to control the temperature uniformity or to control the diffusion of acid. If the control of the acid diffusion distance is not possible, the CDU of the pattern after development and the ultimate resolution decrease. For controlling the acid diffusion, an appropriate PEB temperature is required, and a range of approximately 80 to 100°C is appropriate.

[0066] Another problem when using a low activation energy protecting group is that in the case of a polymer copolymerized with a photoacid generator (PAG), the protecting group may be eliminated during polymerization. Although onium salt PAGs are basically neutral, partial dissociation may occur in the onium salt due to heating during polymerization, or an exchange reaction may occur between the proton of the phenolic hydroxyl group and the cation of the PAG when a repeating unit having a phenolic hydroxyl group is copolymerized simultaneously, generating an acid and causing deprotection of the protecting group. In particular, when a low activation energy protecting group is used, deprotection during polymerization is remarkable.

[0067] As described above, the acid-labile group protecting the carboxylic acid with a tertiary benzyl alcohol has the advantage of excellent etching resistance because it has a benzene ring, but elimination occurs during polymerization when copolymerized with PAG. Attaching an electron-withdrawing group to the benzene ring increases the activation energy of deprotection. This is presumably because the stability of the benzyl cation, the intermediate of deprotection, is reduced by the electron-withdrawing group. It is possible to optimize by attaching an electron-withdrawing group to a protecting group that is very easily deprotected to reduce the reactivity of the deprotection reaction.

[0068] It is said that fluorine atoms have a high absorption for EUV with a wavelength of 13.5 nm, and thus there is a sensitizing effect that improves sensitivity. An improvement in sensitivity is expected by introducing fluorine atoms into the protecting group. However, when fluorine atoms are introduced into the acid-labile group of a tertiary alkyl group, the stability of the intermediate cation of the deprotection reaction becomes very low due to the electron-withdrawing effect of fluorine, resulting in no olefin formation and no deprotection reaction. However, a tertiary acid-labile group having an aromatic group containing fluorine atoms has an optimal stability of the intermediate cation and exhibits an appropriate deprotection reactivity.

[0069] From the above, in order to suppress acid diffusion and improve dissolution contrast and etching resistance, by using Polymer P as the base polymer of a chemically amplified positive resist composition, the alkali dissolution rate contrast before and after exposure is significantly high, the effect of suppressing acid diffusion is high, it has high resolution, the pattern shape and LWR after exposure are good, and it shows even better etching resistance.

[0070] The chemically amplified resist composition of the present invention, in particular, has a high dissolution contrast of the resist film due to an optimal deprotection reaction, a high effect of suppressing acid diffusion, high resolution, an exposure margin, excellent process adaptability, a good pattern shape after exposure, and shows even better etching resistance. Therefore, due to having these excellent characteristics, it has extremely high practicality and is very effective as a material for forming a mask pattern.

[0071] [Repeating unit having a phenolic hydroxy group] Polymer P contains a repeating unit having a phenolic hydroxy group (hereinafter also referred to as repeating unit B). As the repeating unit B, those represented by the following formula (B1) are preferable. [Chemical formula]

[0072] In formula (B1), R A is the same as above. Z B is a single bond or *-C(=O)-O-. * represents a bond to a carbon atom in the main chain. R 11 is a halogen atom, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom. m1 is an integer of 1 to 4. m2 is an integer of 0 to 4. However, 1 ≦ m1 + m2 ≦ 5.

[0073] R 11 The hydrocarbyl groups represented by 11 , as well as the hydrocarbyl moieties of hydrocarbyloxy groups, hydrocarbylcarbonyl groups, hydrocarbylcarbonyloxy groups, and hydrocarbyloxycarbonyl groups, may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (A1). B and R C include those similar to the hydrocarbyl groups exemplified above.

[0074] Examples of the repeating unit B include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chemical formula

[0075]

Chemical formula

[0076]

Chemical formula

[0077] [Repeating unit that generates acid upon exposure] The polymer P contains a repeating unit that generates acid upon exposure (hereinafter, also referred to as repeating unit C). Examples of the repeating unit C include a repeating unit represented by the following formula (C1) (hereinafter, also referred to as repeating unit C1), a repeating unit represented by the following formula (C2) (hereinafter, also referred to as repeating unit C2), a repeating unit represented by the following formula (C3) (hereinafter, also referred to as repeating unit C3), or a repeating unit represented by the following formula (C4) (hereinafter, also referred to as repeating unit C4).

Chemical formula

[0078] In formulas (C1) to (C4), R A is the same as described above. Z 1 is a single bond or a phenylene group. Z 2 is *-C(=O)-O-Z 21 -, *-C(=O)-NH-Z 21 - or *-O-Z 21 -. Z 21 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 3 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-Z 31 -. Z 31 is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond, or a lactone ring, or a phenylene group or a naphthylene group. Z 4 is a single bond or *-Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. 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, *-C(=O)-O-Z 51 -, *-C(=O)-N(H)-Z 51 - or *-O-Z 51 -. Z 51 is an aliphatic hydrocarbylene 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 contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. * represents a bond to a carbon atom in the main chain.

[0079] Z 21 Z 31 and Z 51 The aliphatic hydrocarbylene groups represented by may be linear, branched, or cyclic, and specific examples thereof include those similar to those exemplified in the description of Z A1 in formula (A1).

[0080] Z 41 The hydrocarbylene group represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include, but are not limited to, those shown below.

Chemical formula

[0081] In formula (C1), R 21 and R 22 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group 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 methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group; alkenyl groups having 2 to 20 carbon atoms such as vinyl group, allyl group, propenyl group, butenyl group, hexenyl group; cyclic unsaturated hydrocarbyl groups having 3 to 20 carbon atoms such as cyclohexenyl group; aryl groups having 6 to 20 carbon atoms such as phenyl group, naphthyl group, thienyl group; aralkyl groups such as benzyl group, 1-phenylethyl group, 2-phenylethyl group; groups obtained by combining these, etc. An aryl group is preferred. Further, part or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and part of -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0082] Also, R 21 and R 22 may combine with each other to form a ring together with the sulfur atom to which they are attached. Specifically, examples include those represented by the following formula. In the following formula, the dashed line represents a bond with Z 2 .

Chemical formula

[0083] Examples of the cation of the repeating unit represented by formula (C1) include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chemical formula

[0084]

Chemical formula

[0085]

Chemical formula

[0086]

Chemical formula

[0087]

Chemical formula

[0088]

Chemical formula

[0089]

Chemical formula

[0090] In formula (C1), M - is a non-nucleophilic counter ion. Examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion; fluoroalkyl sulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion, and nonafluorobutanesulfonate ion; aryl sulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, and 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkyl sulfonate ions such as mesylate ion and butanesulfonate ion; imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, and bis(perfluorobutylsulfonyl)imide ion; methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion, etc.

[0091] Furthermore, examples of the non-nucleophilic counter ion include sulfonate anions in which the α-position is substituted with a fluorine atom and represented by the following formula (C1-1) and sulfonate anions in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group and represented by the following formula (C1-2).

Chemical formula

[0092] In formula (C1-1), R 23 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 30 carbon atoms, or a hydrocarbyloxycarbonyl group having 2 to 30 carbon atoms, and may contain a halogen atom, an ether bond, an ester bond, a carbonyl group or lactone ring and may be included. The hydrocarbyl moieties of the hydrocarbyl group, the hydrocarbylcarbonyloxy group, and the hydrocarbyloxycarbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A') described below105 Examples thereof include the same ones as those exemplified as the hydrocarbyl group represented by

[0093] In formula (C1-2), R 24 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and may contain a halogen atom, an ether bond, an ester bond, a carbonyl group or a lactone ring. R 25 is a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. The hydrocarbyl moiety of the hydrocarbyl group and the hydrocarbylcarbonyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include the same ones as those exemplified as the hydrocarbyl group represented by R 105 in formula (3A') described later. R 25 is preferably a trifluoromethyl group.

[0094] Specific examples of the sulfonate anion represented by formula (C1-1) or (C1-2) include, but are not limited to, those shown below. In the following formulas, R 25 is the same as above, and Ac is an acetyl group.

Chemical formula

[0095]

Chemical formula

[0096]

Chemical formula

[0097]

Chemical formula

[0098]

Chemical formula

[0099]

Chem.

[0100]

Chem.

[0101]

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[0102]

Chem.

[0103]

Chem.

[0104]

Chem.

[0105] In formulas (C2) and (C3), L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonic acid ester bond, a carbonate bond or a carbamate bond. Among these, from the viewpoint of synthesis, an ether bond, an ester bond, and a carbonyl group are preferable, and an ester bond and a carbonyl group are more preferable.

[0106] In formula (C2), Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. Among these, for Rf 1 and Rf 2 in order to increase the acid strength of the generated acid, it is preferable that both are fluorine atoms. For Rf 3 and Rf 4is independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. Among these, for improving solvent solubility, Rf 3 and Rf 4 at least one of which is preferably a trifluoromethyl group.

[0107] In formula (C3), Rf 5 and Rf 6 are independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. However, all Rf 5 and Rf 6 will not simultaneously become hydrogen atoms. Among these, for improving solvent solubility, Rf 5 and Rf 6 at least one of which is preferably a trifluoromethyl group.

[0108] In formulas (C2) and (C3), c is an integer of 0 to 3, but 1 is preferred.

[0109] Examples of the anion of the repeating unit represented by formula (C2) include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chemical formula

[0110]

Chemical formula

[0111]

Chemical formula

[0112]

Chemical formula

[0113]

Chemical formula

[0114]

Chem.

[0115] Examples of the anion of the repeating unit represented by the formula (C3) include, but are not limited to, those shown below. In the following formula, R A is the same as defined above.

Chem.

[0116]

Chem.

[0117]

Chem.

[0118] Examples of the anion of the repeating unit represented by the formula (C4) include, but are not limited to, those shown below. In the following formula, R A is the same as defined above.

Chem.

[0119] In formulas (C2) to (C4), A + is an onium cation. Examples of the onium cation include an ammonium cation, a sulfonium cation, and an iodonium cation. Among them, a sulfonium cation or an iodonium cation is preferable, and a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the formula (cation-2) is more preferable.

Chem.

[0120] In formulas (cation-1) and (cation-2), R ct1 ~R ct5 is each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group 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 methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group; alkenyl groups having 2 to 20 carbon atoms such as vinyl group, allyl group, propenyl group, butenyl group, hexenyl group; cyclic unsaturated hydrocarbyl groups having 3 to 20 carbon atoms such as cyclohexenyl group; aryl groups having 6 to 20 carbon atoms such as phenyl group, naphthyl group, thienyl group; aralkyl groups having 7 to 20 carbon atoms such as benzyl group, 1-phenylethyl group, 2-phenylethyl group; and groups obtained by combining these, etc. An aryl group is preferred. Further, part or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, halogen atom, and part of -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, and as a result, it may contain a hydroxy group, fluorine atom, chlorine atom, bromine atom, iodine atom, cyano group, carbonyl group, ether bond, ester bond, sulfonic acid ester bond, carbonate bond, lactone ring, sultone ring, carboxylic acid anhydride (-C(=O)-O-C(=O)-), haloalkyl group, etc.

[0121] Also, R ct1 and R ct2 may combine with each other to form a ring together with the sulfur atom to which they are attached. At this time, examples of the sulfonium cation represented by formula (cation-1) include those represented by the following formula.

Chemical formula

[0122] Examples of the sulfonium cation represented by formula (cation-1) include, but are not limited to, those shown below. [ka]

[0123] [ka]

[0124] [ka]

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] [ka]

[0129] [ka]

[0130] [ka]

[0131]

Chem.

[0132]

Chem.

[0133]

Chem.

[0134]

Chem.

[0135]

Chem.

[0136]

Chem.

[0137]

Chem.

[0138]

Chem.

[0139]

Chem.

[0140]

Chem.

[0141]

Chem.

[0142]

Chem.

[0143] Examples of the iodonium cation represented by formula (cation-2) include, but are not limited to, the following.

Chem.

[0144] Specific structures of the repeating units represented by formulas (C1) to (C4) include any combination of the anions and cations described above.

[0145] As the repeating unit C, repeating units C2, C3, and C4 are preferred from the viewpoint of controlling acid diffusion, repeating units C2 and C4 are more preferred from the viewpoint of the acid strength of the generated acid, and repeating unit C2 is even more preferred from the viewpoint of solvent solubility.

[0146] The polymer in the chemically amplified resist composition of the present invention is characterized by including a repeating unit having an acid-labile group containing a fluorine atom-containing aromatic ring, a repeating unit having a phenolic hydroxy group, and a repeating unit that generates an acid upon exposure. Upon exposure, secondary electrons are generated from the repeating unit having a phenolic hydroxy group, and the secondary electrons are effectively transmitted to the cation at the acid generation site, decomposing the sulfonium cation or iodonium cation to generate the corresponding acid. Since the generated acid is bonded to the polymer main chain, it does not diffuse excessively. Further, the repeating unit having an acid-labile group containing a fluorine atom-containing aromatic ring forms a stable tertiary benzyl cation after the elimination reaction. The tertiary benzyl cation is more stable than the carbocation eliminated from a general tertiary ester-type acid-labile group, so it has high reactivity with an acid. As a result, the dissolution contrast with the developer is high, and the sensitivity of the resist film is improved. Further, by introducing an acid-labile group containing a fluorine atom-containing aromatic ring, the fluorine atom concentration in the polymer can be increased, so the solubility in a solvent is increased, and it dissolves uniformly, and the polymer chains are less likely to aggregate. Due to the synergistic effect of these three repeating units, it is considered possible to form a pattern with high sensitivity and high contrast, and excellent in LWR of line patterns and CDU of hole patterns.

[0147] Polymer P may further contain at least one selected from the repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1) and the repeating unit represented by (a2) (hereinafter also referred to as repeating unit a2). [Chemical formula]

[0148] In formulas (a1) and (a2), R A is the same as described above. Z C is a single bond, a phenylene group, a naphthylene group or *-C(=O)-O-Z C1 -, and Z C1is a saturated hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group. Z D is a single bond or *-C(=O)-O-. * represents a bond to a carbon atom in the main chain. R 12 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. X A and X B are each independently an acid-labile group not containing a fluorine-containing aromatic ring. k is an integer of 0 to 4.

[0149] In formulae (a1) and (a2), X A and X B Examples of the acid-labile group represented by include those described in JP-A-2013-80033 and JP-A-2013-83821.

[0150] Typically, examples of the acid-labile group include those represented by the following formulae (AL-1) to (AL-3).

Chemical formula

[0151] In formulae (AL-1) and (AL-2), R L1 and R L2 are each independently a saturated hydrocarbyl group having 1 to 40 carbon atoms, which may contain a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The saturated hydrocarbyl group may be linear, branched, or cyclic. The saturated hydrocarbyl group preferably has 1 to 20 carbon atoms.

[0152] In formula (AL-1), a is an integer of 0 to 10, and preferably an integer of 1 to 5.

[0153] In formula (AL-2), R L3 and R L4is, independently of each other, a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms, and may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be linear, branched, or cyclic. Further, R L2 , R L3 and R L4 Any two of them may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded or a carbon atom and an oxygen atom. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0154] In formula (AL-3), R L5 , R L6 and R L7 are, independently of each other, a saturated hydrocarbyl group having 1 to 20 carbon atoms, and may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be linear, branched, or cyclic. Further, R L5 , R L6 and R L7 Any two of them may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0155] Examples of the repeating unit a1 include, but are not limited to, those shown below. In the following formulas, R A and X A are the same as those described above.

Chemical formula

[0156]

Chemical formula

[0157]

Chemical formula

[0158] Examples of the repeating unit a2 include, but are not limited to, those shown below. In the following formulas, R A and X B are the same as those described above.

Chemical Formula

[0159] The polymer P may further include a repeating unit represented by the following formula (D1) (hereinafter, also referred to as repeating unit D).

Chemical Formula

[0160] In formula (D1), R A is the same as described above. Z E is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-Z E1 -, where Z E1 is a hydroxy group, an ether bond, an ester bond, or a saturated hydrocarbylene group having 1 to 20 carbon atoms which may contain a lactone ring, or a phenylene group or a naphthylene group. * represents a bond to a carbon atom in the main chain. Y A is a hydrogen atom, or a polar group containing at least one selected from a hydroxy group, a cyano group, a carbonyl group, a carboxy group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic acid anhydride (-C(=O)-O-C(=O)-).

[0161] Examples of the repeating unit D include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chemical Formula

[0162]

Chemical Formula

[0163]

Chem.

[0164]

Chem.

[0165]

Chem.

[0166]

Chem.

[0167]

Chem.

[0168]

Chem.

[0169]

Chem.

[0170]

Chem.

[0171]

Chem.

[0172]

Chem.

[0173]

Chem.

[0174]

Chem.

[0175]

Chem.

[0176]

Chem.

[0177] Polymer P may further contain a repeating unit E derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or derivatives thereof. Examples of the monomer that gives the repeating unit E include, but are not limited to, those shown below.

Chem.

[0178] Polymer P may further contain a repeating unit F derived from indane, vinyl pyridine or vinyl carbazole.

[0179] In polymer P, the content ratios of repeating units A, a1, a2, B, C, D, E, and F are preferably 0 < A < 1.0, 0 ≤ a1 ≤ 0.8, 0 ≤ a2 ≤ 0.8, 0 < B < 1.0, 0 < C < 1.0, 0 ≤ D ≤ 0.8, 0 ≤ E ≤ 0.8, and 0 ≤ F ≤ 0.4, more preferably 0.05 ≤ A ≤ 0.9, 0 ≤ a1 ≤ 0.7, 0 ≤ a2 ≤ 0.7, 0 ≤ a1 + a2 ≤ 0.7, 0.09 ≤ B ≤ 0.55, 0.01 ≤ C ≤ 0.4, 0 ≤ D ≤ 0.7, 0 ≤ E ≤ 0.7, and 0 ≤ F ≤ 0.3, and even more preferably 0.1 ≤ A ≤ 0.8, 0 ≤ a1 ≤ 0.6, 0 ≤ a2 ≤ 0.6, 0 ≤ a1 + a2 ≤ 0.4, 0.1 ≤ B ≤ 0.45, 0.1 ≤ C ≤ 0.45, 0 ≤ D ≤ 0.6, 0 ≤ E ≤ 0.6, and 0 ≤ F ≤ 0.2. When repeating unit C is at least one selected from repeating units C1 to C4, C = C1 + C2 + C3 + C4. Also, A + a1 + a2 + B + C + D + E + F = 1.

[0180] The weight average molecular weight (Mw) of polymer P is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no risk of resolution degradation due to the inability to ensure the difference in dissolution rate before and after exposure. In the present invention, Mw is a polystyrene-equivalent measurement value by gel permeation chromatography (GPC) using THF or N,N-dimethylformamide (DMF) as a solvent.

[0181] Furthermore, in the case of the polymer, when the molecular weight distribution (Mw / Mn) is wide, there are low molecular weight and high molecular weight polymers, so there is a risk that foreign substances will be seen on the pattern or the pattern shape will deteriorate after exposure. Therefore, as the pattern rules are miniaturized, the influence of Mw / Mn tends to increase. To obtain a resist composition suitably used for fine pattern dimensions, the Mw / Mn of the polymer is preferably narrowly dispersed at 1.0 to 2.0.

[0182] To synthesize the polymer, for example, a monomer that gives the above-described repeating unit may be heated in an organic solvent with the addition of a radical polymerization initiator to perform polymerization.

[0183] Examples of the organic solvent used during polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), and the like. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, and the like. The addition amount of these initiators is preferably 0.01 to 25 mol% based on the total of the monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, more preferably 2 to 12 hours from the viewpoint of production efficiency.

[0184] The polymerization initiator may be added to the monomer solution and then supplied to the reaction kettle, or an initiator solution may be prepared separately from the monomer solution, and each may be independently supplied to the reaction kettle. Since there is a possibility that the polymerization reaction may proceed due to radicals generated from the initiator during the standby time and ultra-high molecular weight polymers may be generated, from the viewpoint of quality control, it is preferable to separately prepare and drop the monomer solution and the initiator solution. The acid-labile group may be used as it is introduced into the monomer, or may be protected or partially protected after polymerization. In addition, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol may be used in combination for adjusting the molecular weight. In this case, the addition amount of these chain transfer agents is preferably 0.01 to 20 mol% based on the total of the monomers to be polymerized.

[0185] In the case of a monomer containing a hydroxy group, during polymerization, the hydroxy group may be replaced with an acetal group that is easily deprotected by an acid such as an ethoxyethoxy group, and then deprotected with a weak acid and water after polymerization, or it may be replaced with an acetyl group, a formyl group, a pivaloyl group, etc., and then subjected to alkaline hydrolysis after polymerization.

[0186] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers may be heated and polymerized by adding a radical polymerization initiator in an organic solvent. However, acetoxystyrene or acetoxyvinylnaphthalene may be used, and after polymerization, the acetoxy group may be deprotected by alkali hydrolysis to obtain polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0187] As the base for alkali hydrolysis, aqueous ammonia, triethylamine, etc. can be used. Also, the reaction temperature is preferably -20 to 100 °C, more preferably 0 to 60 °C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0188] In addition, the amount of each monomer in the monomer solution may be appropriately set so as to be, for example, the preferable content ratio of the repeating unit described above.

[0189] The polymer obtained by the manufacturing method may be the reaction solution obtained by the polymerization reaction as the final product, or the powder obtained through a purification process such as a reprecipitation method in which the polymerization solution is added to a poor solvent to obtain a powder may be treated as the final product. However, from the viewpoints of working efficiency and quality stabilization, it is preferable to treat the polymer solution obtained by dissolving the powder obtained through the purification process in a solvent as the final product. Specific examples of the solvent used in this case 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 (PGME), 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 monotert-butyl ether acetate; lactones such as GBL; ketoalcohols such as diacetone alcohol (DAA); high-boiling alcohol solvents such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol; and mixed solvents thereof.

[0190] In the polymer solution, the concentration of the polymer is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0191] It is preferable to perform filter filtration on the reaction solution and the polymer solution. By performing filter filtration, foreign matters and gels that may cause defects can be removed, which is effective in terms of quality stabilization.

[0192] Examples of the material of the filter used for the filter filtration include those made of materials such as fluorocarbon-based, cellulose-based, nylon-based, polyester-based, and hydrocarbon-based materials. However, in the filtration step of the resist composition, filters made of fluorocarbon-based materials such as so-called Teflon (registered trademark), hydrocarbon-based materials such as polyethylene and polypropylene, or nylon are preferred. The pore size of the filter can be appropriately selected according to the target cleanliness, but is preferably 100 nm or less, more preferably 20 nm or less. These filters may be used alone or in combination of a plurality of filters. The filtration method may be such that the solution is passed only once, but it is more preferable to circulate the solution and perform filtration a plurality of times. The filtration step can be performed in any order and number of times in the polymer production process, but it is preferable to filter the reaction solution, polymer solution, or both after the polymerization reaction.

[0193] The polymer may contain two or more polymers having different composition ratios, Mw, and molecular weight distributions.

[0194] [(B) Onium salt type quencher] Examples of the onium salt type quencher of the component (B) include onium salts represented by the following formula (1) or (2). In the present invention, a quencher is a material for preventing the diffusion of the acid generated from the photoacid generator in the chemically amplified resist composition to the unexposed portion by trapping the acid and forming a desired pattern. [Chemical formula]

[0195] In formula (1), R q1 is a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hetero atom, except that the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group. In formula (2), R q2 is a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hetero atom.

[0196] R q1 Specific examples of the hydrocarbyl group represented by R include alkyl groups having 1 to 40 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, tert-pentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group; cycloalkyl groups having 3 to 40 carbon atoms such as cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo[5.2.1.0 2,6 decanyl group, adamantyl group; aryl groups having 6 to 40 carbon atoms such as phenyl group, naphthyl group, anthracenyl group; groups obtained by combining these, etc. Further, part or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, halogen atom, and part of -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, and as a result, it may contain a hydroxy group, fluorine atom, chlorine atom, bromine atom, iodine atom, cyano group, carbonyl group, ether bond, ester bond, sulfonic acid ester bond, carbonate bond, lactone ring, sultone ring, carboxylic acid anhydride (-C(=O)-O-C(=O)-), haloalkyl group, etc.

[0197] R q2 Specific examples of the hydrocarbyl group represented by R include, in addition to the substituents exemplified as specific examples of R q1 fluorinated alkyl groups such as trifluoromethyl group and trifluoroethyl group, and fluorinated aryl groups such as pentafluorophenyl group and 4-trifluoromethylphenyl group.

[0198] Examples of the anion of the onium salt represented by formula (1) include, but are not limited to, those shown below.

Chemical formula

[0199] [Chemical formula]

[0200] [Chemical formula]

[0201] Examples of the anion of the onium salt represented by formula (2) include, but are not limited to, those shown below. [Chemical formula]

[0202] [Chemical formula]

[0203] [Chemical formula]

[0204] In formulas (1) and (2), A + is an onium cation. Preferred examples of the onium cation include the sulfonium cation represented by the aforementioned formula (cation-1), the iodonium cation represented by the aforementioned formula (cation-2), or the ammonium cation represented by the following formula (cation-3). [Chemical formula]

[0205] In formula (cation-3), R ct6 ~R ct9 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. Also, R ct6 and R ct7They may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded. Examples of the hydrocarbyl group include R in formulas (cation-1) and (cation-2). ct1 ~R ct5 Examples of the hydrocarbyl group represented by these are the same as those exemplified as the hydrocarbyl group represented by the formula (cation-1) and (cation-2).

[0206] Examples of the ammonium cation represented by (cation-3) include, but are not limited to, those shown below.

Chemical formula

[0207] Specific examples of the onium salt represented by formula (1) or (2) include any combination of the anions and cations described above. These onium salts can be easily prepared by an ion exchange reaction using known organic chemical methods. For the ion exchange reaction, for example, JP-A-2007-145797 can be referred to.

[0208] The onium salt represented by formula (1) or (2) acts as a quencher in the chemically amplified resist composition of the present invention. This is due to each counter anion of the onium salt being a conjugate base of a weak acid. The weak acid referred to here means one that exhibits an acidity that cannot deprotect the acid-labile group of the acid-labile group-containing unit used in the base polymer. The onium salt represented by formula (1) or (2) functions as a quencher when used in combination with an onium salt type photoacid generator having a conjugate base of a strong acid such as a sulfonic acid with a fluorinated α-position as a counter anion. That is, when an onium salt that generates a strong acid such as a sulfonic acid with a fluorinated α-position and an onium salt that generates a weak acid such as a non-fluorinated sulfonic acid or carboxylic acid are mixed and used, when the strong acid generated from the photoacid generator by high-energy ray irradiation collides with the onium salt having an unreacted weak acid anion, a weak acid is released by salt exchange, and an onium salt having a strong acid anion is generated. Since the strong acid is exchanged for a weak acid with lower catalytic ability in this process, apparently, the acid is deactivated and the acid diffusion can be controlled.

[0209] Here, when the photoacid generator that generates a strong acid is an onium salt, as described above, the strong acid generated by high-energy ray irradiation can be exchanged for a weak acid. On the other hand, it is considered that the weak acid generated by high-energy ray irradiation hardly collides with the onium salt that generates an unreacted strong acid to perform salt exchange. This is due to the phenomenon that the onium cation easily forms an ion pair with the anion of a stronger acid.

[0210] In the chemically amplified resist composition of the present invention, the content of (B) the onium salt type quencher is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, based on 80 parts by mass of (A) the polymer P. If the content of (B) the onium salt type quencher is within the above range, the resolution is good and the sensitivity does not decrease significantly, which is preferable. (B) The onium salt type quencher may be used alone or in combination of two or more.

[0211] [(C) Organic solvent] As the organic solvent for the (C) component, there is no particular limitation as long as it can dissolve each of the components described above and each of the components described below. Examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ketoalcohols such as DAA; ethers such as PGME, 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 monotert-butyl ether acetate; lactones such as GBL; and mixed solvents thereof. When using a polymer containing an acetal-based acid-labile group, a high-boiling alcohol-based solvent, specifically, diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, 1,3-butanediol, etc. can also be added to accelerate the deprotection reaction of the acetal.

[0212] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixed solvents thereof, in which the solubility of the polymer P of the (A) component is particularly excellent, are preferred.

[0213] In the chemically amplified resist composition of the present invention, the content of the (C) organic solvent is preferably 200 to 5,000 parts by mass, more preferably 400 to 3,000 parts by mass, relative to 80 parts by mass of the (A) polymer P. The (C) organic solvent may be used alone or in combination of two or more.

[0214] [(D) Photoacid generator] The chemically amplified resist composition of the present invention may contain a photoacid generator as component (D). The photoacid generator is not particularly limited as long as it is a compound that generates an acid upon irradiation with high-energy rays. Preferred photoacid generators include those represented by the following formula (3).

Chem.

[0215] In formula (3), R 101 , R 102 and R 103 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. Further, R 101 and R 102 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same ones as those exemplified in the description of R ct1 ~R ct5 in formulas (cation-1) and (cation-2). Specific examples of the cation of the sulfonium salt represented by formula (3) include the same ones as those exemplified as specific examples of the sulfonium cation represented by formula (cation-1).

[0216] In formula (3), Xa - is an anion selected from the following formulas (3A) to (3D).

Chem.

[0217] In formula (3A), R fa is a fluorine atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same ones as those exemplified as the hydrocarbyl group represented by R 105 in formula (3A') described later.

[0218] As the anion represented by formula (3A), those represented by the following formula (3A') are preferable. [Chemical formula]

[0219] In formula (3A'), R 104 is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 105 is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a hetero atom. As the hetero atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc. are preferable, and an oxygen atom is more preferable. As the hydrocarbyl group, those having 6 to 30 carbon atoms are particularly preferable from the viewpoint of obtaining high resolution in fine pattern formation.

[0220] R 105 The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, 2-ethylhexyl group, nonyl group, undecyl group, tridecyl group, pentadecyl group, heptadecyl group, icosanyl group; cyclic saturated hydrocarbyl groups having 3 to 38 carbon atoms such as cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-adamantylmethyl group, norbornyl group, norbornylmethyl group, tricyclodecanyl group, tetracyclododecanyl group, tetracyclododecanylmethyl group, dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 38 carbon atoms such as allyl group, 3-cyclohexenyl group; aryl groups having 6 to 38 carbon atoms such as phenyl group, 1-naphthyl group, 2-naphthyl group; aralkyl groups having 7 to 38 carbon atoms such as benzyl group, diphenylmethyl group; groups obtained by combining these, etc. Among these, R 105The aliphatic group is preferred. Further, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Examples of the hydrocarbyl group containing a heteroatom include a tetrahydrofuryl group, a methoxymethyl group, an ethoxymethyl group, a methylthiomethyl group, an acetamidomethyl group, a trifluoroethyl group, a (2-methoxyethoxy)methyl group, an acetoxymethyl group, a 2-carboxy-1-cyclohexyl group, a 2-oxopropyl group, a 4-oxo-1-adamantyl group, a 3-oxocyclohexyl group, etc.

[0221] Regarding the synthesis of the sulfonium salt having the anion represented by the formula (3A'), it is detailed in JP-A-2007-145797, JP-A-2008-106045, JP-A-2009-7327, JP-A-2009-258695, etc. Further, the sulfonium salts described in JP-A-2010-215608, JP-A-2012-41320, JP-A-2012-106986, JP-A-2012-153644, etc. are also preferably used.

[0222] Examples of the anion represented by the formula (3A) include the same ones as those exemplified for M in the formula (C1), but are not limited thereto. -

[0223] In the formula (3B), R fb1 and R fb2 are each independently a fluorine atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in the formula (3A').105 Examples thereof include the same as those exemplified as the hydrocarbyl group represented by R fb1 and R fb2 are preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Also, R fb1 and R fb2 may be bonded to each other to form a ring together with the group (-CF2-SO2-N - -SO2-CF2-) to which they are bonded. At this time, the group obtained by bonding R fb1 and R fb2 to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0224] In formula (3C), R fc1 , R fc2 and R fc3 are each independently a fluorine atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include the same as those exemplified as the hydrocarbyl group represented by R 105 in formula (3A'). R fc1 , R fc2 and R fc3 are preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Also, R fc1 and R fc2 may be bonded to each other to form a ring together with the group (-CF2-SO2-C - -SO2-CF2-) to which they are bonded. At this time, the group obtained by bonding R fc1 and R fc2 to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0225] In formula (3D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include the same as those exemplified as R 105Examples thereof include the same as those exemplified as the hydrocarbyl group represented by

[0226] Regarding the synthesis of the sulfonium salt having the anion represented by the formula (3D), it is detailed in JP-A-2010-215608 and JP-A-2014-133723.

[0227] Examples of the anion represented by the formula (3D) include, but are not limited to, the following. [Chemical formula]

[0228] [Chemical formula]

[0229] The photoacid generator having the anion represented by the formula (3D) does not have a fluorine atom at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position, and thus has sufficient acidity to cleave the acid-labile group in the base polymer. Therefore, it can be used as a photoacid generator.

[0230] Also, the component (D) light As the acid generator, those represented by the following formula (4) are also preferable. [Chemical formula]

[0231] In the formula (4), R 201 and R 202 are each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a hetero atom. R 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a hetero atom. Also, R 201 , R 202 and R 203Any two of them may combine with each other to form a ring together with the sulfur atom to which they are attached. At this time, as the ring, in the description of formula (C1), R 21 and R 22 may be the same as those exemplified as the rings that can be formed together with the sulfur atom to which they are attached.

[0232] R 201 and R 202 The hydrocarbyl groups represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, tert-pentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group; cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms such as cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo[5.2.1.0 2,6 decanyl group, adamantyl group; aryl groups having 6 to 30 carbon atoms such as phenyl group, naphthyl group, anthracenyl group; groups obtained by combining these, and the like. Further, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, and the like.

[0233] R 203The hydrocarbylene group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups having 1 to 30 carbon atoms such as methane diyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group; cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms such as cyclopentane diyl group, cyclohexane diyl group, norbornane diyl group, adamantane diyl group; arylene groups having 6 to 30 carbon atoms such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, tert-butylnaphthylene group; groups obtained by combining these, and the like. Further, some or all of the hydrogen atoms of the hydrocarbylene group may 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 hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, or the like. The heteroatom is preferably an oxygen atom.

[0234] In formula (4), L Ais a hydrocarbylene group having 1 to 20 carbon atoms which may contain a single bond, an ether bond, or a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 203 and the like exemplified as the hydrocarbylene group represented by

[0235] In formula (4), X a , X b , X c and X d are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. However, at least one of X a , X b , X c and X d is a fluorine atom or a trifluoromethyl group.

[0236] As the photoacid generator represented by formula (4), those represented by the following formula (4') are preferable.

Chemical formula

[0237] In formula (4'), L A is the same as above. X e is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 301 , R 302 and R 303 are each independently a hydrogen atom, or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to the hydrocarbyl group exemplified as R 105 in formula (3A'). x and y are each independently an integer of 0 to 5, and z is an integer of 0 to 4.

[0238] Examples of the photoacid generator represented by formula (4) include those similar to the photoacid generators exemplified as the photoacid generator represented by formula (2) in JP-A-2017-026980.

[0239] Among the recording light photoacid generators, those containing an anion represented by formula (3A') or (3D) are particularly preferred because they have low acid diffusion and excellent solubility in solvents. In addition, those represented by formula (4') are particularly preferred because they have extremely low acid diffusion.

[0240] As other photoacid generators, onium salts represented by the following formula (5-1) or (5-2) can also be used.

Chemical formula

[0241] In formulas (5-1) and (5-2), p is an integer satisfying 1 ≤ p ≤ 3. q and r are integers satisfying 1 ≤ q ≤ 5, 0 ≤ r ≤ 3, and 1 ≤ q + r ≤ 5. q is preferably an integer satisfying 1 ≤ q ≤ 3, more preferably 2 or 3. r is preferably an integer satisfying 0 ≤ r ≤ 2.

[0242] In formulas (5-1) and (5-2), X BI is an iodine atom or a bromine atom, and when p and / or q are 2 or more, they may be the same or different from each other.

[0243] In formulas (5-1) and (5-2), L 11 is a single bond, an ether bond or an ester bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched or cyclic.

[0244] In formulas (5-1) and (5-2), L 12When p is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms, and when p is 2 or 3, it is a (p + 1)-valent linking group having 1 to 20 carbon atoms, and the linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.

[0245] In formulas (5-1) and (5-2), R 401 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms or a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond, or -N(R 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-O-R 401D . R 401A and R 401B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 401C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. R 401Dis an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyl group and hydrocarbylcarbonyloxy group may be linear, branched or cyclic. When p and / or r is 2 or more, each R 401 may be the same as or different from each other.

[0246] Among these, R 401 is preferably a hydroxy group, -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-O-R 401D , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group or the like.

[0247] In formulas (5-1) and (5-2), Rf 11 to Rf 14 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, and at least one of these is a fluorine atom or a trifluoromethyl group. Further, Rf 11 and Rf 12 may combine to form a carbonyl group. In particular, it is preferable that both Rf 13 and Rf 14 are fluorine atoms.

[0248] In formulas (5-1) and (5-2), R 402 , R 403 , R 404 , R 405 and R 406is independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those exemplified as the hydrocarbyl group represented by R 101 ~R 103 in the description of formula (3). Further, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone group, a sulfone group or a sulfonium salt-containing group, and a part of -CH2- of the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond or a sulfonic acid ester bond. Also, R 402 and R 403 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, examples of the ring include those similar to those exemplified as the ring that can be formed by bonding R 101 and R 102 to each other together with the sulfur atom to which they are bonded in the description of formula (3).

[0249] Examples of the cation of the sulfonium salt represented by formula (5-1) include those similar to those exemplified as the sulfonium cation represented by formula (C4). Also, examples of the cation of the iodonium salt represented by formula (5-2) include those similar to those exemplified as the iodonium cation represented by formula (cation-2).

[0250] Examples of the anion of the onium salts represented by formulas (5-1) and (5-2) include those similar to those exemplified as the anions of the onium salts represented by formulas (3-1) and (3-2) in JP-A-2020-118959.

[0251] When the chemically amplified resist composition of the present invention contains (D) a photoacid generator, its content is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 20 parts by mass, based on 80 parts by mass of the (A) polymer P. If the addition amount of the (D) photoacid generator is within the above range, the resolution is good, and there is no risk of foreign matter problems during or after development or peeling of the resist film, which is preferable. The (D) photoacid generator can be used alone or in combination of two or more.

[0252] [(E) nitrogen-containing quencher] The chemically amplified resist composition of the present invention may further contain a nitrogen-containing quencher. Examples of the nitrogen-containing quencher as the component (E) include primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonic acid ester bond. Also, compounds in which a primary or secondary amine is protected with a carbamate group, such as those described in Japanese Patent No. 3790649, can be mentioned.

[0253] In addition, a sulfonium salt of sulfonic acid having a nitrogen-containing substituent may be used as the nitrogen-containing quencher. Such a compound functions as a quencher in the unexposed portion and functions as a so-called photodecomposable base that loses its quenching ability by neutralization with the acid generated by itself in the exposed portion. By using a photodecomposable base, the contrast between the exposed portion and the unexposed portion can be further enhanced. For photodecomposable bases, for example, JP-A-2009-109595, JP-A-2012-46501, etc. can be referred to.

[0254] When the chemically amplified resist composition of the present invention contains (E) a nitrogen-containing quencher, its content is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass, based on 80 parts by mass of the (A) polymer P. The (E) nitrogen-containing quencher may be used alone or in combination of two or more.

[0255] [(F) Surfactant] The chemically amplified resist composition of the present invention may further contain (F) a surfactant. As the surfactant of the component (F), preferably, it is a surfactant that is insoluble or hardly soluble in water and soluble in an alkaline developer, or a surfactant that is insoluble or hardly soluble in water and an alkaline developer. As such surfactants, those described in JP-A-2010-215608 and JP-A-2011-16746 can be referred to.

[0256] As the surfactant that is insoluble or hardly soluble in water and an alkaline developer, among the surfactants described in the above publications, FC-4430 (manufactured by 3M), Surflon (registered trademark) S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Orfin (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and oxetane ring-opening polymers represented by the following formula (surf-1) are preferable. [Chemical formula]

[0257] Here, regardless of the above description, R, Rf, A, B, C, m, and n are only applicable to the formula (surf-1). R is an aliphatic group having 2 to 4 valences and 2 to 5 carbon atoms. Examples of the aliphatic group include, as the divalent group, an ethylene group, a 1,4-butylene group, a 1,2-propylene group, a 2,2-dimethyl-1,3-propylene group, a 1,5-pentylene group, etc., and as the trivalent or tetravalent group, the following groups can be mentioned. [Chemical formula] (In the formula, the dashed line is a bond, and each is a partial structure derived from glycerol, trimethylolethane, trimethylolpropane, or pentaerythritol.)

[0258] Among these, a 1,4-butylene group, a 2,2-dimethyl-1,3-propylene group, etc. are preferable.

[0259] Rf is a trifluoromethyl group or a pentafluoroethyl group, preferably a trifluoromethyl group. m is an integer from 0 to 3, n is an integer from 1 to 4, and the sum of n and m is the valence of R, which is an integer from 2 to 4. A is 1. B is an integer from 2 to 25, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. Also, each structural unit in formula (surf-1) does not define its arrangement, and they may be block-bonded or randomly bonded. Regarding the production of the surfactant of the partially fluorinated oxetane ring-opening polymer system, it is detailed in U.S. Patent No. 5650483 and the like.

[0260] Surfactants that are insoluble or poorly soluble in water and soluble in alkaline developers have the function of reducing water seepage and leaching by orienting on the surface of the resist film when no resist protective film is used in ArF immersion lithography. Therefore, it is useful for suppressing the elution of water-soluble components from the resist film and reducing damage to the exposure apparatus. Also, during alkaline aqueous solution development after exposure or PEB, it solubilizes and is less likely to become foreign matter that causes defects, so it is useful. Such surfactants have the property of being insoluble or poorly soluble in water and soluble in alkaline developers, and are polymer-type surfactants, also called hydrophobic resins. Those with particularly high water repellency and improved lubricity are preferred.

[0261] Examples of such polymer-type surfactants include those containing at least one selected from the repeating units represented by the following formulas (6A) to (6E).

Chemical formula

[0262] In formulas (6A) to (6E), R B is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. W 1 is -CH2-, -CH2CH2-, -O-, or two separated -H's. R s1 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. R s2is a single bond or a linear or branched hydrocarbylene group having 1 to 5 carbon atoms. R s3 each independently represents a hydrogen atom, a hydrocarbyl group or fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid-labile group. R s3 When R is a hydrocarbyl group or fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be interposed between carbon-carbon bonds. R s4 is a (u + 1)-valent hydrocarbon group or fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer of 1 to 3. R s5 each independently represents a hydrogen atom or a group represented by -C(=O)-O-R sa wherein R sa is a fluorinated hydrocarbyl group having 1 to 20 carbon atoms. R s6 is a hydrocarbyl group or fluorinated hydrocarbyl group having 1 to 15 carbon atoms, and an ether bond or a carbonyl group may be interposed between carbon-carbon bonds thereof.

[0263] R s1 The hydrocarbyl group represented by R is preferably a saturated hydrocarbyl group and may be linear, branched or cyclic. Specific examples thereof include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group; and cyclic saturated hydrocarbyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group. Among these, those having 1 to 6 carbon atoms are preferred.

[0264] R s2 The hydrocarbylene group represented by R is preferably a saturated hydrocarbylene group and may be linear, branched or cyclic. Specific examples thereof include methylene group, ethylene group, propylene group, butylene group, pentylene group and the like.

[0265] R s3 or R s6The hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples thereof include saturated hydrocarbyl groups, aliphatic unsaturated hydrocarbyl groups such as alkenyl groups and alkynyl groups, etc., but saturated hydrocarbyl groups are preferred. As the saturated hydrocarbyl group, R s1 In addition to those exemplified as the hydrocarbyl group represented by , an n-undecyl group, an n-dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, etc. can be mentioned. R s3 Or R s6 Examples of the fluorinated hydrocarbyl group represented by include groups in which some or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbyl group are substituted with fluorine atoms. As described above, an ether bond or a carbonyl group may be interposed between these carbon-carbon bonds.

[0266] R s3 Examples of the acid-labile group represented by include the groups represented by the aforementioned formulas (AL-1) to (AL-3), a trialkylsilyl group in which each alkyl group is an alkyl group having 1 to 6 carbon atoms, an oxoalkyl group having 4 to 20 carbon atoms, etc.

[0267] R s4 The (u + 1)-valent hydrocarbon group or fluorinated hydrocarbon group represented by can be linear, branched, or cyclic. Specific examples thereof include groups obtained by further removing u hydrogen atoms from the aforementioned hydrocarbyl group or fluorinated hydrocarbyl group, etc.

[0268] R saAs the fluorinated hydrocarbyl group represented by , a saturated one is preferable, and it may be linear, branched or cyclic. Specific examples thereof include those in which some or all of the hydrogen atoms of the hydrocarbyl group are substituted with fluorine atoms. For example, trifluoromethyl group, 2,2,2-trifluoroethyl group, 3,3,3-trifluoro-1-propyl group, 3,3,3-trifluoro-2-propyl group, 2,2,3,3-tetrafluoropropyl group, 1,1,1,3,3,3-hexafluoroisopropyl group, 2,2,3,3,4,4,4-heptafluorobutyl group, 2,2,3,3,4,4,5,5-octafluoropentyl group, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl group, 2-(perfluorobutyl)ethyl group, 2-(perfluorohexyl)ethyl group, 2-(perfluorooctyl)ethyl group, 2-(perfluorodecyl)ethyl group and the like can be mentioned.

[0269] Examples of the repeating units represented by formulae (6A) to (6E) include, but are not limited to, those shown below. In the following formulae, R B is the same as described above.

Chemical formula

[0270]

Chemical formula

[0271]

Chemical formula

[0272]

Chemical formula

[0273]

Chemical formula

[0274] The polymer surfactant may further contain other repeating units other than the repeating units represented by the formulas (6A) to (6E). Examples of the other repeating units include repeating units obtained from methacrylic acid, α-trifluoromethyl acrylic acid derivatives, and the like. In the polymer surfactant, the content of the repeating units represented by the formulas (6A) to (6E) is preferably 20 mol% or more, more preferably 60 mol% or more, and still more preferably 100 mol% in all the repeating units.

[0275] The Mw of the polymer surfactant is preferably from 1,000 to 500,000, more preferably from 3,000 to 100,000. The Mw / Mn is preferably from 1.0 to 2.0, more preferably from 1.0 to 1.6.

[0276] As a method for synthesizing the polymer surfactant, a method of heating and polymerizing a monomer containing an unsaturated bond that gives the repeating units represented by the formulas (6A) to (6E) and, if necessary, other repeating units in an organic solvent by adding a radical initiator can be mentioned. Examples of the organic solvent used during polymerization include toluene, benzene, THF, diethyl ether, dioxane, and the like. Examples of the polymerization initiator include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, and the like. 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 as it is introduced into the monomer, or may be protected or partially protected after polymerization.

[0277] When synthesizing the polymer surfactant, a known chain transfer agent such as dodecyl mercaptan or 2-mercaptoethanol may be used to adjust the molecular weight. In that case, the addition amount of these chain transfer agents is preferably 0.01 to 10 mol% based on the total number of moles of the monomers to be polymerized.

[0278] When the chemically amplified resist composition of the present invention contains (F) a surfactant, its content is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass, based on 80 parts by mass of the polymer (A). If the content of the (F) surfactant is 0.1 part by mass or more, the receding contact angle between the resist film surface and water is sufficiently improved. If it is 50 parts by mass or less, the dissolution rate of the resist film surface in the developer is small, and the height of the formed fine pattern is sufficiently maintained. The (F) surfactant may be used alone or in combination of two or more.

[0279] [(G) Other components] The chemically amplified resist composition of the present invention may contain, as (G) other components, a compound that decomposes by an acid to generate an acid (acid-generating compound), an organic acid derivative, a fluorine-substituted alcohol, a compound having a molecular weight (Mw) of 3,000 or less whose solubility in a developer changes by the action of an acid (dissolution inhibitor), and the like. As the acid-generating compound, reference can be made to the compounds described in JP-A-2009-269953 or JP-A-2010-215608. When the acid-generating compound is contained, its content is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass, based on 80 parts by mass of the polymer (A). If the content is too large, it is difficult to control diffusion, and resolution degradation and pattern shape degradation may occur. As the organic acid derivative, fluorine-substituted alcohol, and dissolution inhibitor, reference can be made to the compounds described in JP-A-2009-269953 or JP-A-2010-215608.

[0280] [Pattern formation method] The pattern formation method of the present invention includes a step of forming a resist film on a substrate using the above-described chemically amplified resist composition, a step of exposing the resist film with high-energy rays, and a step of developing the exposed resist film using a developer.

[0281] As the substrate, for example, 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.) can be used.

[0282] The resist film can be formed by applying the chemically amplified resist composition onto a substrate by a method such as spin coating so that the film thickness is preferably 0.05 to 2 μm, and then prebaking this on a hot plate, preferably at 60 to 150°C for 1 to 10 minutes, more preferably at 80 to 140°C for 1 to 5 minutes.

[0283] Examples of the high energy ray used for exposure of the resist film include i-ray, KrF excimer laser light, ArF excimer laser light, EB, EUV, etc. When using i-ray, KrF excimer laser light, ArF excimer laser light or EUV for exposure, it is carried out by irradiating with an exposure amount of preferably 1 to 200 mJ / cm 2 and more preferably 10 to 100 mJ / cm 2 while using a mask for forming the target pattern. When using EB for exposure, it is irradiated with an exposure amount of preferably 1 to 300 μC / cm 2 and more preferably 10 to 200 μC / cm 2 while using a mask for forming the target pattern or directly.

[0284] In addition to the normal exposure method, it is also possible to use the immersion method in which a liquid having a refractive index of 1.0 or more is interposed between the resist film and the projection lens for exposure. In that case, it is also possible to use a protective film insoluble in water.

[0285] The water-insoluble protective film is used to prevent elution from the resist film and increase the hydrophilicity of the film surface, and can be roughly classified into two types. One is an organic solvent peelable type that needs to be peeled off before alkali aqueous solution development with an organic solvent that does not dissolve the resist film, and the other is an alkali aqueous solution soluble type that is soluble in an alkali developer and removes both the soluble part of the resist film and the protective film. The latter is particularly based on a polymer having a 1,1,1,3,3,3-hexafluoro-2-propanol residue that is insoluble in water and soluble in an alkali developer, and a material dissolved in an alcohol solvent having 4 or more carbon atoms, an ether solvent having 8 to 12 carbon atoms, or a mixed solvent thereof is preferred. The surfactant described above that is insoluble in water and soluble in an alkali developer can also be a material dissolved in an alcohol solvent having 4 or more carbon atoms, an ether solvent having 8 to 12 carbon atoms, or a mixed solvent thereof.

[0286] After exposure, PEB may be performed. PEB can be carried out, for example, by heating on a hot plate, preferably at 60 to 150 °C for 1 to 5 minutes, more preferably at 80 to 140 °C for 1 to 3 minutes.

[0287] Development can be carried out, for example, using a developer of an alkali aqueous solution such as preferably 0.1 to 5% by mass, more preferably 2 to 3% by mass of tetramethylammonium hydroxide (TMAH), and can be carried out by a conventional method such as a dip method, a puddle method, or a spray method, preferably for 0.1 to 3 minutes, more preferably for 0.5 to 2 minutes. By developing in this way, a positive pattern is formed on the substrate.

[0288] Also, after forming the resist film, pure water rinsing may be performed to extract an acid generator or the like from the film surface or wash away particles, or rinsing may be performed to remove the water remaining on the film after exposure.

[0289] Furthermore, pattern formation may be performed by a double patterning method. As the double patterning method, there are a trench method in which a base of a 1:3 trench pattern is processed by first exposure and etching, the position is shifted, and a 1:3 trench pattern is formed by second exposure to form a 1:1 pattern, and a line method in which a first base of a 1:3 isolated remaining pattern is processed by first exposure and etching, the position is shifted, and a second base in which a 1:3 isolated remaining pattern is formed under the first base is processed to form a 1:1 pattern with a pitch halved.

[0290] In the pattern formation method of the present invention, a negative tone development method may be used in which an organic solvent is used as a developer instead of the alkaline aqueous solution developer to dissolve and develop the unexposed portion. Examples of the organic solvent developer 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, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl 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, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

Example

[0291] Hereinafter, the present invention will be specifically described with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples. The equipment used is as follows. ·IR: NICOLET 6700 manufactured by Thermo Fisher Scientific · 1 1H-NMR: ECA-500 manufactured by JEOL Ltd. · 19 19F-NMR: ECA-500 manufactured by JEOL Ltd.

[0292] [1] Synthesis of Monomers [Synthesis Example 1-1] Synthesis of Monomer MA-1 [Chemical Formula]

[0293] (1) Synthesis of Intermediate In-1 Under a nitrogen atmosphere, a Grignard reagent was prepared from magnesium (160.5 g), 4-bromofluorobenzene (1155 g) and THF (3300 g). While maintaining the internal temperature at 45 °C or lower, a solution composed of raw material M-1 (348.5 g) and THF (700 g) was added dropwise. After stirring at an internal temperature of 50 °C for 2 hours, the reaction solution was ice-cooled, and an aqueous solution mixture of ammonium chloride (660 g) and 3.0 mass% hydrochloric acid aqueous solution (3960 g) was added dropwise to stop the reaction. Toluene (4500 mL) was added, and normal aqueous work-up was performed. After distilling off the solvent and purifying by distillation, 865 g of intermediate In-1 was obtained as a colorless oily substance (yield 94%).

[0294] (2) Synthesis of Monomer MA-1 Under a nitrogen atmosphere, methacrylic acid chloride (821 g) was added dropwise to a solution of intermediate In-1 (865 g), triethylamine (1022 g), dimethylaminopyridine (68.5 g) and acetonitrile (3150 mL) at an internal temperature of 60 °C or lower. After aging at an internal temperature of 55 °C for 20 hours, the reaction solution was cooled with ice, and saturated aqueous sodium bicarbonate (2000 mL) was added dropwise to stop the reaction. The mixture was extracted with toluene (4200 mL), subjected to a normal aqueous work-up, the solvent was distilled off, and then vacuum distillation was performed to obtain 1012 g of monomer MA-1 as a colorless transparent oil (yield 81%).

[0295] IR spectral data of monomer MA-1 and 1 1H-NMR, 19 The results of 19F-NMR are shown below. IR (D-ATR): ν = 2982, 2930, 1717, 1637, 1603, 1512, 1454, 1406, 1383, 1366, 1329, 1304, 1271, 1234, 1179, 1163, 1137, 1105, 1095, 1015, 941, 835, 813, 724, 655, 607, 556, 533 cm -1 . 1 1H-NMR (600 MHz in DMSO-d6): δ = 7.38 (2H, dd), 7.14 (2H, dd), 6.02 (1H, d), 5.64 (1H, d), 1.84 (3H, s), 1.73 (6H, s) ppm. 19 19F-NMR (600 MHz in DMSO-d6): δ = -117.49 (1F, m) ppm.

[0296] [Synthesis Example 1-2] Synthesis of monomer MA-2 [Chemical formula]

[0297] (1) Synthesis of intermediate In-2 Under a nitrogen atmosphere, a Grignard reagent was prepared from magnesium (59 g), 1,4-dichlorobutane (146 g), and THF (1000 mL). While maintaining the internal temperature at 50 °C or lower, a solution consisting of raw material M-2 (154 g) and THF (150 mL) was added dropwise. After stirring at an internal temperature of 50 °C for 2 hours, the reaction solution was ice-cooled, and an aqueous solution mixture of ammonium chloride (240 g) and 3.0 mass% hydrochloric acid aqueous solution (1450 g) was added dropwise to stop the reaction. Toluene (800 mL) was added, and normal aqueous work-up was performed. After distilling off the solvent, vacuum distillation was carried out to obtain 175 g of intermediate In-2 as a colorless transparent oily substance (yield 98%).

[0298] (2) Synthesis of monomer MA-2 Synthesis was carried out in the same manner as in Synthesis Example 1-1(2) except that intermediate In-2 was used instead of intermediate In-1, and monomer MA-2 was obtained as a colorless transparent oily substance (yield 82%).

[0299] IR spectral data of monomer MA-2 and 1 H-NMR, 19 the results of F-NMR are shown below. IR(D-ATR): ν= 3048, 2960, 2877, 1885, 1717, 1636, 1606, 1512, 1451, 1407, 1377,1331, 1302, 1231, 1165, 1151, 1098, 1043, 1014, 982, 967, 941, 898, 833, 814, 725, 652, 581, 550 cm -1 . 1 H-NMR(600MHz in DMSO-d6): δ= 7.38(2H, dd), 7.12(2H, dd), 6.00(1H, d), 5.62(1H, d), 2.37(2H, m), 2.03(2H, m), 1.81(3H, s), 1.77-1.72(4H, m) ppm. 19 F-NMR (600MHz in DMSO-d6): δ= -117.13(1F, m) ppm.

[0300] [Synthesis Examples 1-3 to 1-18] Synthesis of Monomers MA-3 to MA-18 Using the corresponding raw materials, the following monomers MA-3 to MA-18 were synthesized. [Chemical Formula]

[0301] IR spectral data of monomer MA-3 and 1 H-NMR, 19 the results of F-NMR are shown below. IR(D-ATR): ν = 2983, 2930, 1720, 1637, 1616, 1592, 1489, 1446, 1435, 1401, 1383, 1366, 1329, 1302, 1284, 1273, 1176, 1135, 1101, 1069, 1009, 939, 895, 872, 830, 814, 785, 698, 653, 573, 518, 471 cm -1 . 1 H-NMR(600MHz in DMSO-d6): δ = 7.37(1H, m), 7.18(1H, m), 7.14(1H, m), 7.06(1H, m), 6.04(1H, d), 5.66(1H, d), 1.85(3H, s), 1.73(6H, s) ppm. 19 F-NMR (600MHz in DMSO-d6): δ = -114.35(1F, m) ppm.

[0302] IR spectral data of monomer MA-4 and 1 H-NMR, 19 the results of F-NMR are shown below. IR(D-ATR): ν = 2985, 1720, 1638, 1621, 1452, 1411, 1384, 1367, 1328, 1303, 1271, 1167, 1128, 1115, 1100, 1 068, 1017, 942, 841, 814, 715, 651, 620, 605, 544 cm -1 . 1 1H-NMR (600 MHz in DMSO-d6): δ = 7.69 (2H, d), 7.56 (2H, d), 6.06 (1H, d), 5.67 (1H, d), 1.85 (3H, s), 1.75 (6H, s) ppm. 19 19F-NMR (600 MHz in DMSO-d6): δ = -62.13 (3F, s) ppm.

[0303] IR spectrum data of monomer MA-5 and 1 1H-NMR, 19 19F-NMR results are shown below. IR (D-ATR): ν = 2984, 1720, 1638, 1512, 1454, 1410, 1384, 1367, 1330, 1303, 1259, 1223, 1170, 1139, 1098, 1019, 941, 850, 813, 672, 613, 560 cm -1 . 1 1H-NMR (600 MHz in DMSO-d6): δ = 7.46 (2H, dd), 7.31 (2H, dd), 6.04 (1H, d), 5.66 (1H, d), 1.85 (3H, s), 1.73 (6H, s) ppm. 19 19F-NMR (600 MHz in DMSO-d6): δ = -57.98 (3F, s) ppm.

[0304] IR spectrum data of monomer MA-6 and 1 1H-NMR, 19 19F-NMR results are shown below. IR(D-ATR): ν = 2960, 2877, 1719, 1637, 1616, 1591, 1490, 1443, 1401, 1378, 1331, 1301, 1269, 1198, 1155, 1077, 1046, 1008, 976, 941, 867, 838, 816, 783, 696, 658, 523, 462 cm -1 . 1 H-NMR(600 MHz in DMSO-d6): δ = 7.35(1H, m), 7.17(1H, m), 7.12(1H, m), 7.06(1H, m), 6.03(1H, s), 5.64(1H, s), 2.34(2H, m), 2.06(2H, m), 1.83(3H, s), 1.77 - 1.74(4H, m) ppm. 19 F-NMR (600 MHz in DMSO-d6): δ = -114.61(1F, m) ppm.

[0305] IR spectrum data of monomer MA-7 and 1 H-NMR, 19 the results of F-NMR are shown below. IR(D-ATR): ν = 2958, 2877, 1717, 1637, 1616, 1581, 1491, 1450, 1402, 1377, 1330, 1303, 1218, 1176, 1154, 1103, 1041, 1008, 983, 970, 938, 900, 862, 814, 756, 653, 550, 479 cm -1 . 1 H-NMR(600 MHz in DMSO-d6): δ = 7.43(1H, m), 7.29(1H, m), 7.12(2H, m), 5.97(1H, s), 5.60(1H, s), 2.46(2H, m), 2.10(2H, m), 1.80(3H, s), 1.77 - 1.72(4H, m) ppm. 19F-NMR (600 MHz in DMSO-d6): δ = -113.83 (1F, m) ppm.

[0306] IR spectral data of monomer MA-8 and 1 1H-NMR, 19 the results of 19F-NMR are shown below. IR (D-ATR): ν = 2961, 2878, 1719, 1637, 1610, 1520, 1451, 1424, 1378, 1330, 1298, 1285, 1196, 1159, 1118, 1044, 1008, 977, 942, 868, 816, 775, 709, 650, 617, 579, 460 cm -1 . 1 1H-NMR (600 MHz in DMSO-d6): δ = 7.37 (2H, m), 7.19 (1H, m), 6.02 (1H, s), 5.63 (1H, s), 2.35 (2H, m), 2.04 (2H, m), 1.82 (3H, s), 1.77 - 1.73 (4H, m) ppm. 19 19F-NMR (600 MHz in DMSO-d6): δ = -140.13 (1F, m), -142.34 (1F, m) ppm.

[0307] IR spectral data of monomer MA-9 and 1 1H-NMR, 19 the results of 19F-NMR are shown below. IR (D-ATR): ν = 3048, 2960, 2877, 1885, 1717, 1636, 1606, 1512, 1451, 1407, 1377, 1331, 1302, 1231, 1165, 1151, 1098, 1043, 1014, 982, 967, 941, 898, 833, 814, 725, 652, 581, 550 cm -1 . 11H-NMR (600 MHz in DMSO-d6): δ = 7.38 (2H, dd), 7.12 (2H, dd), 6.00 (1H, d), 5.62 (1H, d), 2.37 (2H, m), 2.03 (2H, m), 1.81 (3H, s), 1.78 - 1.74 (4H, m) ppm. 19 19F-NMR (600 MHz in DMSO-d6): δ = -111.10 (2F, m) ppm.

[0308] IR spectral data of monomer MA-10 and 1 1H-NMR, 19 19F-NMR results are shown below. IR (D-ATR): ν = 2962, 2879, 1719, 1637, 1620, 1451, 1411, 1378, 1327, 1159, 1125, 1071, 1017, 984, 943, 899, 839, 816, 650, 602, 523 cm -1 . 1 1H-NMR (600 MHz in DMSO-d6): δ = 7.67 (2H, dd), 7.55 (2H, dd), 6.05 (1H, d), 5.66 (1H, d), 2.35 (2H, m), 2.10 (2H, m), 1.83 (3H, s), 1.81 - 1.74 (4H, m) ppm. 19 19F-NMR (600 MHz in DMSO-d6): δ = -62.15 (3F, s) ppm.

[0309] IR spectral data of monomer MA-11 and 1 1H-NMR, 19 19F-NMR results are shown below. IR (D-ATR): ν = 3048, 2936, 2862, 1719, 1637, 1602, 1513, 1450, 1409, 1377, 1364, 1328, 1303, 1280, 1253, 1223, 1171, 1162, 1130, 1103, 1035, 1013, 961, 939, 916, 906, 847, 833, 824, 810, 778, 723, 652, 604, 578, 550, 506 cm -1 . 1 1H-NMR (600 MHz in DMSO-d6): δ = 7.35 (2H, dd), 7.14 (2H, dd), 6.06 (1H, d), 5.66 (1H, d), 2.39 (2H, m), 1.86 (3H, s), 1.78 - 1.52 (7H, m), 1.29 (1H, m) ppm. 19 19F-NMR (600 MHz in DMSO-d6): δ = -117.42 (1F, m) ppm.

[0310] IR spectral data of monomer MA-12 and 1 1H-NMR, 19 19F-NMR results are shown below. IR (D-ATR): ν = 2937, 2863, 1721, 1637, 1595, 1511, 1451, 1402, 1378, 1328, 1303, 1260, 1219, 1166, 1130, 1113, 1035, 1015, 962, 940, 924, 907, 847, 806, 678, 640, 614, 556 cm -1 . 1 1H-NMR (600 MHz in DMSO-d6): δ = 7.44 (2H, dd), 7.30 (2H, dd), 6.07 (1H, d), 5.67 (1H, d), 2.38 (2H, dm), 1.87 (3H, s), 1.76 (2H, tm), 1.68 - 1.50 (5H, m), 1.29 (1H, m) ppm. 19F-NMR (600 MHz in DMSO-d6): δ = -57.96 (3F, s) ppm.

[0311] [Comparative Synthesis Examples 1-1 to 1-8] Synthesis of Comparative Monomers MAX-1 to MAX-8 Using the corresponding raw materials, Comparative Monomers MAX-1 to MAX-8 were synthesized as comparative monomers. [Chemical Formula]

[0312] [2] Synthesis of Polymer Among the monomers used for the synthesis of the polymer, those other than Monomers MA-1 to MA-18 and Comparative Monomers MAX-1 to MAX-8 are as follows. [Chemical Formula]

[0313] [Chemical Formula]

[0314] [Chemical Formula]

[0315] [Chemical Formula]

[0316] [Synthesis Example 2-1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, 50.1 g of monomer MA-1, 24.8 g of monomer MB-1, 38.0 g of monomer MC-1, 3.96 g of V-601 (manufactured by Fuji Film Wako Pure Chemical Corporation), and 127 g of MEK were placed in a flask to prepare a monomer-polymerization initiator solution. 46 g of MEK was taken in another flask under a nitrogen atmosphere, heated to 80 °C with stirring, and then the monomer-polymerization initiator solution was added dropwise over 4 hours. After the addition was complete, stirring was continued for 2 hours while maintaining the temperature of the polymerization solution at 80 °C, and then it was cooled to room temperature. The obtained polymerization solution was added dropwise to 2000 g of vigorously stirred hexane, and the precipitated polymer was separated by filtration. Further, the obtained polymer was washed twice with 600 g of hexane and then vacuum dried at 50 °C for 20 hours to obtain a white powdery polymer P-1 (yield 98.1 g, yield 98%). The Mw of polymer P-1 was 10,900 and Mw / Mn was 1.82. Here, Mw is a polystyrene-equivalent measurement value by GPC using DMF as a solvent.

[0317] [Chemical formula]

[0318] [Synthesis Examples 2-2 to 2-30, Comparative Synthesis Examples 2-1 to 2-15] Synthesis of Polymers P-2 to P-30 and CP-1 to CP-15 The polymers shown in Tables 1 to 3 were produced in the same manner as in Synthesis Example 2-1, except that the types and mixing ratios of the respective monomers were changed. In Tables 1 to 3, the introduction ratio is in mol%.

[0319] [Table 1]

[0320] [Table 2]

[0321] [Table 3]

[0322] [3] Preparation of chemically amplified resist composition [Examples 1-1 to 1-31, Comparative Examples 1-1 to 1-15] Polymers P (P-1 to P-30), comparative polymers (CP-1 to CP-15), photoacid generators (PAG-1, PAG-2), quenchers (SQ-1 to SQ-3, AQ-1) were dissolved in a solvent containing 100 ppm of FC-4430 manufactured by 3M as a surfactant with the compositions shown in Tables 4 to 6 below, and the resulting solution was filtered through a 0.2 μm Teflon (registered trademark) filter to prepare a chemically amplified resist composition.

[0323] [Table 4]

[0324] [Table 5]

[0325] [Table 6]

[0326] In Tables 4 to 6, each component is as follows. · Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol)

[0327] · Photoacid generator: PAG-1, PAG-2 [Chemical formula]

[0328] · Quencher: SQ-1 to SQ-3, AQ-1 [Chemical formula]

[0329] [4] EUV Lithography Evaluation (1) [Examples 2-1 to 2-31, Comparative Examples 2-1 to 2-15] Each of the chemically amplified resist compositions (R-1 to R-31, CR-1 to CR-15) shown in Tables 4 to 6 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a film thickness of 20 nm, and prebaked at 100 °C for 60 seconds using a hot plate to produce a resist film with a film thickness of 50 nm. This was exposed to an LS pattern with a wafer size of 18 nm and a pitch of 36 nm using an EUV scanner NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination) manufactured by ASML while changing the exposure dose and focus (exposure dose pitch: 1 mJ / cm 2 , focus pitch: 0.020 μm), and after exposure, PEB was performed at the temperatures shown in Tables 7 to 9 for 60 seconds. Then, paddle development was performed for 30 seconds with a 2.38% by mass TMAH aqueous solution, rinsed with a surfactant-containing rinse material, spin-dried, and a positive pattern was obtained. The obtained LS pattern was observed with a length measurement SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, and the sensitivity, exposure latitude (EL), LWR, depth of focus (DOF), and collapse limit were evaluated according to the following methods. The results are shown in Tables 7 to 9.

[0330] [Sensitivity Evaluation] The optimum exposure dose E op (mJ / cm 2 ) at which an LS pattern with a line width of 18 nm and a pitch of 36 nm was obtained was determined, and this was taken as the sensitivity. The smaller this value, the higher the sensitivity.

[0331] [EL Evaluation] From the exposure doses formed within the range of ±10% (16.2 to 19.8 nm) of the space width of 18 nm in the LS pattern, EL (unit: %) was determined by the following formula. The larger this value, the better the performance. EL (%) = (|E1 - E2| / E op ) × 100 E1: The optimum exposure dose that gives an LS pattern with a line width of 16.2 nm and a pitch of 36 nm E2: Optimal exposure dose for an LS pattern with a line width of 19.8 nm and a pitch of 36 nm E op : Optimal exposure dose for an LS pattern with a line width of 18 nm and a pitch of 36 nm

[0332] [LWR evaluation] E op The LS pattern obtained by irradiation was measured for the dimensions at 10 locations in the longitudinal direction of the line, and from the results, three times the standard deviation (σ) (3σ) was determined as the LWR. The smaller this value, the smaller the roughness and the more uniform the line width pattern can be obtained.

[0333] [DOF evaluation] As the focus depth evaluation, the focus range formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm dimension in the LS pattern was determined. The larger this value, the wider the focus depth.

[0334] [Evaluation of the collapse limit of the line pattern] The line dimensions of each exposure dose at the optimal focus of the LS pattern were measured at 10 locations in the longitudinal direction. The thinnest line dimension obtained without collapse was defined as the collapse limit dimension. The smaller this value, the better the collapse limit.

[0335]

Table 7

[0336]

Table 8

[0337]

Table 9

[0338] From the results shown in Tables 7 to 9, it was confirmed that the chemically amplified resist composition of the present invention has good sensitivity, excellent various lithography performances, and shows strong performance against pattern collapse.

[0339] [5] EUV Lithography Evaluation (2) [Examples 3-1 to 3-31, Comparative Examples 3-1 to 3-15] Each chemically amplified resist composition (R-1 to R-31, CR-1 to CR-15) shown in Tables 10 to 12 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a film thickness of 20 nm, pre-baked at 105°C for 60 seconds using a hot plate, and a resist film with a film thickness of 50 nm was produced. This was exposed using an EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask for a hole pattern with a wafer-level dimension of pitch 46 nm and +20% bias) manufactured by ASML, PEB was performed at the temperatures described in Tables 10 to 12 for 60 seconds using a hot plate, and development was performed for 30 seconds with a 2.38 mass% TMAH aqueous solution to form a hole pattern with a dimension of 23 nm. Using a length-measuring SEM (CG6300) manufactured by Hitachi High-Tech Corporation, the exposure dose when a hole dimension of 23 nm was formed was measured and taken as the sensitivity. Also, the dimensions of 50 holes at this time were measured, and three times the standard deviation (σ) calculated from the results was taken as the dimension variation (CDU). The results are shown in Tables 10 to 12.

[0340]

Table 10

[0341]

Table 11

[0342]

Table 12

[0343] From the results shown in Tables 10 to 12, it was confirmed that the chemically amplified resist composition of the present invention has good sensitivity and is excellent in CDU.

Claims

1. (A) A polymer P that contains a repeating unit having an acid-labile group containing a fluorine atom-containing aromatic ring represented by the following formula (A1), a repeating unit having a phenolic hydroxy group, and a repeating unit that generates an acid upon exposure represented by any one of the following formulas (C1) to (C4), and whose solubility in a developer changes by the action of an acid. (B) An onium salt type quencher, and (C) A solvent (However, it does not contain a base polymer containing at least one selected from a repeating unit having an imide group to which an aromatic group substituted with an iodine atom is bonded, a repeating unit in which a hydrogen atom of a carboxy group is substituted with an acid-labile group, and a repeating unit in which a hydrogen atom of a phenolic hydroxy group is substituted with an acid-labile group.). 【Chemical Formula 1】 (wherein, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.) Z A is a single bond, a phenylene group, a naphthylene group or *-C(=O)-O-Z A1 -. Z A1 is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group. * represents a bond to a carbon atom in the main chain. R B and R C are each independently a methyl group or an ethyl group, and R B and R C may combine with each other to form a cyclopentane ring or a cyclohexane ring together with the carbon atom to which they are attached. R 1 is, independently of each other, a fluorine atom, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a pentafluoroethyl group, a pentafluoropropyl group, a 1,1,1,3,3,3-hexafluoro-2-propyl group, a fluoromethoxy group, a difluoromethoxy group, a trifluoromethoxy group, a 2,2,2-trifluoroethoxy group, a pentafluoroethoxy group, a pentafluoropropoxy group or a 1,1,1,3,3,3-hexafluoro-2-propoxy group. R 2 is independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. n1 is an integer of 1 or 2. n2 is 0. n3 is 1. ) [Chemical Formula 2] (wherein, R A is the same as described above. Z 1 is a single bond or a phenylene group. Z 2 is *-C(=O)-O-Z 21 -, *-C(=O)-NH-Z 21 - or *-O-Z 21 -. Z 21 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 3 is a single bond, a phenylene group, a naphthylene group or *-C(=O)-O-Z 31 -. Z 31 is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group. Z 4 is a single bond or *-Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. 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, *-C(=O)-O-Z 51 -, *-C(=O)-N(H)-Z 51 - or *-O-Z 51 -. Z 51 is an aliphatic hydrocarbylene 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 contain a carbonyl group, an ester bond, an ether bond or a hydroxy group. * represents a bond with a carbon atom in the main chain. R 21 and R 22 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. Further, R 21 and R 22 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonic acid ester bond, a carbonate bond or a carbamate bond. Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. Rf 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. However, all of the Rf 5 and Rf 6 do not simultaneously become hydrogen atoms. M - is a non-nucleophilic counterion. A + is an onium cation. c is an integer from 0 to 3. )

2. R 1 The chemically amplified resist composition according to claim 1, wherein R is a fluorine atom, a trifluoromethyl group or a trifluoromethoxy group.

3. The chemically amplified resist composition according to claim 1 or 2, wherein the repeating unit having a phenolic hydroxy group is represented by the following formula (B1). 【Chemical Formula 3】 (wherein, R A is the same as described above. Z B is a single bond or *-C(=O)-O-. * represents a bond with a carbon atom in the main chain. R 11 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom, a cyano group, or a hetero atom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom. m1 is an integer from 1 to 4. m2 is an integer from 0 to 4. However, 1 ≦ m1 + m2 ≦ 5. )

4. The chemically amplified resist composition according to any one of claims 1 to 3, wherein the onium salt type quencher is represented by the following formula (1) or (2). 【Chemical Formula 4】 (wherein, R q1 is a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hetero atom, provided that the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is excluded from those substituted with a fluorine atom or a fluoroalkyl group). R q2 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom. A + is an onium cation.)

5. A + The chemically amplified resist composition according to any one of claims 1 to 4, wherein A is a cation represented by the following formula (cation-1) or (cation-2). 【Chemical Formula 5】 (In the formula, R ct1 ~R ct5 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. Further, R ct1 and R ct2 may combine with each other to form a ring together with the sulfur atom to which they are attached.)

6. The polymer P further contains a repeating unit represented by the following formula (a1) or (a2) The chemically amplified resist composition according to any one of claims 1 to 5. 【Chemical Formula 6】 (wherein, R A is the same as described above. Z C is a single bond, a phenylene group, a naphthylene group or *-C(=O)-O-Z C1 -, and Z C1 is a saturated hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group. Z D is a single bond or *-C(=O)-O-. * represents a bond with a carbon atom in the main chain. R 12 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. X A and X B are each independently an acid-labile group that does not contain a fluorine-containing aromatic ring. k is an integer from 0 to 4. )

7. The chemically amplified resist composition according to any one of claims 1 to 6, wherein the polymer P further contains a repeating unit represented by the following formula (D1). 【Chemical Formula 7】 (wherein, R A is the same as described above. Z E is a single bond, a phenylene group, a naphthylene group or *-C(=O)-O-Z E1 -, and Z E1 is a saturated hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group. * represents a bond to a carbon atom in the main chain. Y A is a hydrogen atom or a polar group containing at least one selected from a hydroxy group, a cyano group, a carbonyl group, a carboxy group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (—C(═O)—O—C(═O)—).)

8. The chemically amplified resist composition according to any one of claims 1 to 7, further comprising a photoacid generator.

9. The chemically amplified resist composition according to any one of claims 1 to 8, further comprising a surfactant.

10. A pattern forming method including a step of forming a resist film on a substrate using the chemically amplified resist composition according to any one of claims 1 to 9, a step of exposing the resist film to high energy rays, and a step of developing the exposed resist film using a developer.

11. The pattern forming method according to claim 10, wherein the high energy ray is an i-ray, a KrF excimer laser beam, an ArF excimer laser beam, an electron beam, or an extreme ultraviolet ray having a wavelength of 3 to 15 nm.

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