Chemically amplified resist composition and patterning process

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 high integration of integrated circuits, finer pattern formation has been required, and chemically amplified resists catalyzed by acid alone are used in the processing of 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 photomask blanks when manufacturing photomasks for semiconductor production.

[0003] Polymers having a large amount of aromatic skeletons with 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 to light near 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 a base polymer for a positive EB lithography resist composition or an EUV lithography resist composition, a material that solubilizes in an alkaline developer by deprotecting an acid-decomposable protecting group that masks the acidic functional group of the phenolic side chain of the base polymer using the acid generated from the photoacid generator by irradiating high-energy rays as a catalyst is mainly used. Further, as the acid-decomposable protecting group, a tertiary alkyl group, a tert-butoxycarbonyl group, an acetal group, etc. have been mainly used. Here, when using a protecting group with a relatively small activation energy required for deprotection such as an acetal group, there is an advantage that a highly sensitive resist film can be obtained. However, 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 has a great impact on sensitivity and resolution, many studies have been conducted.

[0006] In addition, in an attempt to improve sensitivity, multiple bonds or aromatic rings have been introduced 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 capable of further higher sensitivity and improving 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 having high sensitivity and improved LWR and CDU, and a pattern forming method using the same in photolithography using high energy rays, particularly EB lithography and EUV lithography.

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 chemically amplified resist composition containing 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, it is possible to form a pattern 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, and completed the present invention.

[0011] That is, the present invention provides the following chemically amplified resist composition and a pattern forming 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 (A2), 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 (however, it does not contain a repeating unit in which a hydrogen atom of a carboxy group is substituted with a pyridine ring-containing tertiary hydrocarbyl group). (B) An onium salt type quencher, and (C) A solvent The chemically amplified resist composition containing (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] (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 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. R B and R C are each independently a methyl group or an ethyl group having 1 to 10 carbon atoms, and R B and R C may be bonded to each other to form a cyclopentane ring or a cyclohexane ring together with the carbon atom to which they are bonded. R 1is independently a fluorine atom, 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, fluoromethoxy group, difluoromethoxy group, trifluoromethoxy group, 2,2,2-trifluoroethoxy group, pentafluoroethoxy group, pentafluoropropoxy group or 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 hetero atom. n1 is an integer of 1 or 2. n2 is 0. ) [Chemical formula] (In the formula, 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 5is 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 21 and R 22 may combine with each other to form a ring together with the sulfur atom to which they are attached. 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 of 0 to 3. ) 2. The chemically amplified resist composition according to claim 1, which does not contain a nitrogen-containing quencher. 3.R 1 The chemically amplified resist composition according to claim 1 or 2, wherein R is a fluorine atom, a trifluoromethyl group, or a trifluoromethoxy group. 4. The chemically amplified resist composition according to any one of claims 1 to 3, wherein the repeating unit having a phenolic hydroxy group is represented by the following formula (B1).

Chemical formula

Chemical formula

Chemical formula

Chemical formula

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

Mode 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 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.

[0017] Z A1The aliphatic hydrocarbylene group represented by [[ ]] is may be linear, branched, or cyclic. Specific examples thereof include C1-C20 alkanediyl groups 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; C3-C20 cycloalkanediyl groups such as cyclopropanediyl group, cyclobutane-1,1-diyl group, cyclobutanediyl group, cyclopentanediyl group, cyclohexanediyl group; C4-C20 polycyclic saturated hydrocarbylene groups such as adamantanediyl group, norbornanediyl group; and divalent groups obtained by combining these, etc.

[0018] Z in formula (A1) A Structures obtained by changing [[ ]] 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 and the like.

[0023] Also, 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. Examples of the ring include cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring and the like. 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 and the like. 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 and the like. Among these, R 1is 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, it is preferably a benzene ring with n3 being 0.

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

Chemical formula

[0028] The monomer A1 that gives 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 Pre-A1 which is a monomer precursor.

[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 the 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) until the reaction is completed, 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 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 following the reaction by GC or TLC until the reaction is completed, 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, those shown below. 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]

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[0040]

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[0041]

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[0042]

Chem.

[0043]

Chem.

[0044]

Chem.

[0045]

Chem.

[0046]

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[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]

Chem.

[0061]

Chem.

[0062]

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[0063]

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[0064]

Chem.

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

[0066] Another problem when using low-activation energy protecting groups is that in the case of polymers copolymerized with photoacid generators (PAGs), the protecting groups may be eliminated during polymerization. Although onium salt PAGs are basically neutral, partial dissociation may occur in the onium salts due to heating during polymerization, or when repeating units with phenolic hydroxyl groups are copolymerized simultaneously, an acid generation reaction may occur due to the exchange reaction between the proton of the phenolic hydroxyl group and the cation of the PAG, resulting in deprotection of the protecting group. Especially when using low-activation energy protecting groups, 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. However, when copolymerized with PAG, elimination occurs during polymerization. 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 extremely low due to the electron-withdrawing effect of fluorine, so that the deprotection reaction does not occur without the generation of olefins. 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 reactivity of deprotection.

[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 excellent etching resistance.

[0070] The chemically amplified resist composition of the present invention, in particular, has a high dissolution contrast of the resist film by an optimal deprotection reaction, a high effect of suppressing acid diffusion, has high resolution, has an exposure margin, is excellent in process adaptability, has a good pattern shape after exposure, and shows more excellent 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 described 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 and 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 are the same as those exemplified as the hydrocarbyl groups represented by.

[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 heteroatom. 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 exemplified in the description of Z A1 in formula (A1).

[0080] Z 41 The hydrocarbylene group represented by the formula may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include, but are not limited to, the following. [Chemical formula] (In the formula, the dashed line represents a bond.)

[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. Among them, an aryl 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, a halogen atom, etc., and some 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 formula, 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 a sulfonic acid anion in which the α-position is substituted with a fluorine atom represented by the following formula (C1-1) and a sulfonic acid anion in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group represented by the following formula (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, a lactone ring, or a fluorine atom. The hydrocarbyl moiety 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 later. 105Those similar to the ones exemplified as the hydrocarbyl group represented by [are included].

[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 those similar to the ones 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 described above, and Ac is an acetyl group. [Chemical formula]

[0095] [Chemical formula]

[0096] [Chemical formula]

[0097] [Chemical formula]

[0098] [Chemical formula]

[0099] [Chemical formula]

[0100] [Chemical formula]

[0101] [Chemical formula]

[0102] [Chemical formula]

[0103] [Chemical formula]

[0104] [Chemical formula]

[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 preferred, and an ester bond and a carbonyl group are more preferred.

[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 formula (C3) include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chem.

[0116]

Chem.

[0117]

Chem.

[0118] Examples of the anion of the repeating unit represented by formula (C4) include, but are not limited to, those shown below. In the following formulas, R A is the same as described 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. Preferably, it is a sulfonium cation or an iodonium cation, and more preferably, it is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by formula (cation-2).

Chem.

[0120] In formulas (cation-1) and (cation-2), R ct1 ~R ct5 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 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 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.

Chemical formula

[0123]

Chemical formula

[0124]

Chemical formula

[0125]

Chemical formula

[0126]

Chemical formula

[0127]

Chemical formula

[0128]

Chemical formula

[0129]

Chemical formula

[0130]

Chemical formula

[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, those shown below.

Chem.

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

[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 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. Upon exposure, secondary electrons are generated from the repeating unit having a phenolic hydroxy group, and the secondary electrons effectively transfer to the cation at the acid generation site, causing the sulfonium cation or iodonium cation to decompose and 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 acid. As a result, the dissolution contrast with the developer is high, and the sensitivity of the resist film is improved. In addition, 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 the 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] The 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 that does not contain a fluorine-containing aromatic ring. k is an integer from 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, a fluorine atom, etc. 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 from 0 to 10, preferably an integer from 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 hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, etc. The hydrocarbyl group may be linear, branched or cyclic. Also, R L2 and 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 the 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 and R L6 and R L7 are, independently of each other, a saturated hydrocarbyl group having 1 to 20 carbon atoms, and may contain a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, etc. The hydrocarbyl group may be linear, branched or cyclic. Also, R L5 and 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, the following. In the following formulas, R A and X B are the same as described above.

Chemical Formula

[0159] The polymer P may further contain 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, the following. 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 a derivative 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 still 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, and 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 a decrease in resolution 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 having a wide molecular weight distribution (Mw / Mn), there are low molecular weight and high molecular weight polymers, so there is a risk that foreign substances may be seen on the pattern or the shape of the pattern may deteriorate after exposure. Therefore, as the pattern rules become finer, 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, monomers that give the above-described repeating units may be heated in an organic solvent with the addition of a radical polymerization initiator to carry out polymerization.

[0183] As organic solvents used during polymerization, there may be mentioned toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), etc. As the polymerization initiator, there may be mentioned 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, etc. 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, and 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 proceeds due to radicals generated from the initiator during the standby time and a superpolymer is formed, from the viewpoint of quality control, it is preferable to independently 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. Further, 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 substituted 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 may be substituted 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 subjected to heat polymerization 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. 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] The amount of each monomer in the monomer solution may be appropriately set, for example, so as to achieve the preferable content ratio of the repeating units described above.

[0189] The polymer obtained by the manufacturing method may use the reaction solution obtained by the polymerization reaction as the final product, or the polymer solution obtained by subjecting the polymerization solution to a purification process such as a reprecipitation method of adding the polymerization solution 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 by the purification process in a solvent as the final product. Specific examples of the solvent used at that time 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 to the unexposed portion by trapping the acid generated from the photoacid generator in the chemically amplified resist composition 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; cyclic saturated hydrocarbyl 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, and the like. 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, a halogen atom, etc., 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, 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, and the like.

[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]

Chem.

[0200]

Chem.

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

Chem.

[0202]

Chem.

[0203]

Chem.

[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).

Chem.

[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 combined with each other to form a ring together with the nitrogen atom to which they are attached. Examples of the hydrocarbyl group include R in formulas (cation-1) and (cation-2). ct1 ~R ct5 Examples of the hydrocarbyl group represented thereby include the same ones as those exemplified as the hydrocarbyl group represented by formula (cation-1).

[0206] Examples of the ammonium cation represented by formula (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 an acid having an acidity that cannot deprotect the acid-labile group of the acid-labile group-containing unit used in the base polymer. When the onium salt represented by formula (1) or (2) is used in combination with an onium salt type photoacid generator having a conjugate base of a strong acid such as a sulfonic acid whose α-position is fluorinated as a counter anion, it functions as a quencher. That is, when an onium salt that generates a strong acid such as a sulfonic acid whose α-position is fluorinated 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 and undergoes 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] (C) As the organic solvent, there is no particular limitation as long as it can dissolve each of the aforementioned components and each of the components described below. 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, high-boiling alcohol solvents, 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).

Chemical formula

[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 heteroatom. 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 to R ct5 in formulas (cation-1) and (cation-2). Further, 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).

Chemical formula

[0217] In formula (3A), R fa is 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 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 heteroatom. As the heteroatom, 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 105Preferably, it is an aliphatic group. 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 a part of -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 described in detail 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. - 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 ones as those exemplified as the hydrocarbyl group represented by .

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

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

[0228] [Chemical formula]

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

[0230] In addition, as a photoacid generator other than the photoacid generator bonded to the base polymer chain of component (D), those represented by the following formula (4) are also preferable. [Chemical formula]

[0231] In 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. Further, 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 combine with each other to form a ring similar to 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 group 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; 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 and other cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms; 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 a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- of the hydrocarbyl group may be substituted with a group containing a hetero atom 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.

[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 methanediyl 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 cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, adamantanediyl 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, a halogen atom, etc., and some of the -CH2- of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and 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. As the heteroatom, an oxygen atom is preferable.

[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 those similar to the examples 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 described 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 from 0 to 5, and z is an integer from 0 to 4.

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

[0239] Among the other 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. Also, 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 formulae (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 formulae (5-1) and (5-2), X BI is an iodine atom or a bromine atom, and when p and / or q is 2 or more, they may be the same or different from each other.

[0243] In formulae (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 formulae (5-1) and (5-2), L 12 is a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and a (p + 1)-valent linking group having 1 to 20 carbon atoms when p is 2 or 3, 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 C1-C20 hydrocarbyl group, a C1-C20 hydrocarbyloxy group, a C2-C20 hydrocarbylcarbonyl group, a C2-C20 hydrocarbyloxycarbonyl group, a C2-C20 hydrocarbylcarbonyloxy group or a C1-C20 hydrocarbylsulfonyloxy group 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 C1-C6 saturated hydrocarbyl group. R 401C is a hydrogen atom or a C1-C6 saturated hydrocarbyl group, which may contain a halogen atom, a hydroxy group, a C1-C6 saturated hydrocarbyloxy group, a C2-C6 saturated hydrocarbylcarbonyl group or a C2-C6 saturated hydrocarbylcarbonyloxy group. R 401D is a C1-C16 aliphatic hydrocarbyl group, a C6-C14 aryl group or a C7-C15 aralkyl group, which may contain a halogen atom, a hydroxy group, a C1-C6 saturated hydrocarbyloxy group, a C2-C6 saturated hydrocarbylcarbonyl group or a C2-C6 saturated hydrocarbylcarbonyloxy group. 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, etc.

[0247] In formulas (5-1) and (5-2), Rf 11 ~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. Also, 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 406 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 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 groups represented by R 101 ~R 103 in the description of formula (3). Also, 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 some of the -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 403may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, as the ring, in the description of formula (3), R 101 and R 102 may be the same as those exemplified as the rings that can be formed together with the sulfur atom to which they are bonded.

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

[0250] Examples of the anion of the onium salt represented by formulas (5-1) and (5-2) include the same ones as 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 P80. 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 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, and 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. Further, compounds in which a primary or secondary amine is protected with a carbamate group, such as those described in Japanese Patent No. 3790649, can also 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 area and functions as a so-called photodecomposable base that loses its quenching ability by neutralization with its own generated acid in the exposed area. By using a photodecomposable base, the contrast between the exposed area and the unexposed area can be further enhanced. For the photodecomposable base, reference can be made to, for example, JP-A-2009-109595, JP-A-2012-46501, and the like.

[0254] When the chemically amplified resist composition of the present invention contains the (E) nitrogen-containing quencher, its content is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass, relative to 80 parts by mass of the polymer (A). 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 an (F) surfactant. The surfactant as the component (F) is preferably 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 a surfactant, reference can be made to those described in JP-A-2010-215608 and JP-A-2011-16746.

[0256] Examples of surfactants that are insoluble or poorly soluble in water and alkaline developers include, among the surfactants described in the above publication, 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), etc. are preferable. [Chemical formula]

[0257] Here, regardless of the above description, R, Rf, A, B, C, m, and n are only applicable to 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 divalent groups such as ethylene group, 1,4-butylene group, 1,2-propylene group, 2,2-dimethyl-1,3-propylene group, 1,5-pentylene group, etc., and trivalent or tetravalent groups include the following. [Chemical formula] (In the formula, the dashed lines are bonds, and each is a partial structure derived from glycerol, trimethylolethane, trimethylolpropane, or pentaerythritol.)

[0258] Among these, 1,4-butylene group, 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 order, and they may be bonded blockwise or randomly. Regarding the production of a surfactant based on a partially fluorinated oxetane ring-opening polymer, it is detailed in U.S. Patent No. 5,650,483 and the like.

[0260] A surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer has a 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, and is also useful because it solubilizes during alkaline aqueous solution development after exposure or PEB and is less likely to become foreign matter causing defects. Such a surfactant has the property of being insoluble or poorly soluble in water and soluble in an alkaline developer, is a polymer-type surfactant, is also called a hydrophobic resin, and 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 may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include saturated hydrocarbyl groups, aliphatic unsaturated hydrocarbyl groups such as alkenyl groups and alkynyl groups, etc., with saturated hydrocarbyl groups being 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. may 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 Examples of the (u + 1)-valent hydrocarbon group or fluorinated hydrocarbon group represented by may 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 [formula], a saturated one is preferred, 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 formulas (6A) to (6E) include, but are not limited to, those shown below. In the following formulas, 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 formulas (6A) to (6E). Examples of the other repeating units include repeating units obtained from methacrylic acid, α-trifluoromethylacrylic acid derivatives, and the like. In the polymer surfactant, the content of the repeating units represented by 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 1,000 to 500,000, and more preferably 3,000 to 100,000. Mw / Mn is preferably 1.0 to 2.0, and more preferably 1.0 to 1.6.

[0276] As a method for synthesizing the polymer surfactant, a method of adding a radical initiator to a monomer containing an unsaturated bond that gives repeating units represented by formulas (6A) to (6E) and, if necessary, other repeating units in an organic solvent and heating and polymerizing them 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, known chain transfer agents such as dodecyl mercaptan and 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 (A) polymer P. 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-proliferating compound), an organic acid derivative, a fluorine-substituted alcohol, a compound having a molecular weight of 3,000 or less whose solubility in a developer changes by the action of an acid (dissolution inhibitor), etc. As the acid-proliferating compound, reference can be made to the compounds described in JP-A-2009-269953 or JP-A-2010-215608. When the acid-proliferating 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 (A) polymer P. If the content is too large, it is difficult to control diffusion, and deterioration of resolution and pattern shape 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 to 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 pre-baking 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-line, KrF excimer laser light, ArF excimer laser light, EB, EUV, etc. When using i-line, KrF excimer laser light, ArF excimer laser light or EUV for exposure, it is carried out by irradiating with a mask for forming a target pattern so that the exposure dose is preferably 1 to 200 mJ / cm 2 and more preferably 10 to 100 mJ / cm 2 When using EB for exposure, it is irradiated with a mask for forming a target pattern or directly so that the exposure dose is preferably 1 to 300 μC / cm 2 and more preferably 10 to 200 μC / cm 2 in this way.

[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 products 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, and 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 an alkali aqueous solution developer 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] In addition, 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] The present invention will be specifically described below with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples. The apparatuses used are 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 consisting 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 a mixed aqueous solution 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, the intermediate In-1 was obtained as a colorless oily substance (865 g, yield 94%) by distillation purification.

[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 ice-cooled, and saturated aqueous sodium hydrogen carbonate (2000 mL) was added dropwise to stop the reaction. After extraction with toluene (4200 mL), normal aqueous work-up, and evaporation of the solvent, vacuum distillation was performed to obtain 1012 g of monomer MA-1 as a colorless transparent oily substance (yield 81%).

[0295] The 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 cooled with ice, 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 and 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 and 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 Structure Diagram]

[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, 1168, 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 spectral 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 spectral 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 1H-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 19F-NMR (600 MHz in DMSO-d6): δ = -114.61 (1F, m) ppm.

[0305] IR spectrum data of monomer MA-7 and 1 1H-NMR, 19 the results of 19F-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 1H-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 Structure]

[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 Structure]

[0313] [Chemical Structure]

[0314] [Chemical Structure]

[0315] [Chemical Structure]

[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 completion of the dropwise addition, 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-converted 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, CP-1 to CP-15 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] The polymers P (P-1 to P-30), comparative polymers (CP-1 to CP-15), photoacid generators (PAG-1, PAG-2), and 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 pre-baked 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 dimension of 18 nm and a pitch of 36 nm on the wafer 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 with a 2.38% by mass TMAH aqueous solution for 30 seconds, rinsing was performed with a rinsing material containing a surfactant, spin drying was performed, and a positive pattern was obtained. The obtained LS pattern was observed with a length measuring SEM (CG6300) manufactured by Hitachi High-Tech 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 taken 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% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a film thickness of 20 nm, prebaked 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 then exposed using an EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask for a hole pattern with a pitch of 46 nm and a +20% bias in the on-wafer dimension) 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 carried out for 30 seconds with a 2.38% by 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-Technologies 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 (3σ) 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 (A2), a repeating unit having a phenolic hydroxy group, and a repeating unit that generates an acid upon exposure represented by any of the following formulas (C1) to (C4) (however, it does not contain a repeating unit in which the hydrogen atom of the carboxy group is substituted with a pyridine ring-containing tertiary hydrocarbyl group), (B)An onium salt type quencher, and (C)A solvent A chemically amplified resist composition containing (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 the hydrogen atom of the carboxy group is substituted with an acid-labile group, and a repeating unit in which the hydrogen atom of the phenolic hydroxy group is substituted with an acid-labile group). 【Chemical 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 having 1 to 10 carbon atoms, and R B and R C may be bonded to each other to form a cyclopentane ring or a cyclohexane ring together with the carbon atom to which they are bonded. R 1 is, independently of one another, a fluorine atom, 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, fluoromethoxy group, difluoromethoxy group, trifluoromethoxy group, 2,2,2-trifluoroethoxy group, pentafluoroethoxy group, pentafluoropropoxy group or 1,1,1,3,3,3-hexafluoro-2-propoxy group. R 2 is, independently of each other, 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. 【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 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 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 each independently represents a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms, provided that all of the Rf 5 and Rf 6 do not simultaneously become hydrogen atoms. M - is a non-nucleophilic counter ion. A + is an onium cation. c is an integer of 0 to 3.

2. The chemically amplified resist composition according to Claim 1, which does not contain a nitrogen-containing type quencher.

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

4. The chemically amplified resist composition according to any one of Claims 1 to 3, wherein the repeating unit having a phenolic hydroxy group is represented by the following formula (B1). [Chemical 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 heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. m1 is an integer of 1 to 4. m2 is an integer of 0 to 4. However, 1 ≦ m1 + m2 ≦ 5.

5. The chemically amplified resist composition according to any one of Claims 1 to 4, 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 hetero atom. A + is an onium cation.)

6. A + The chemically amplified resist composition according to any one of claims 1 to 5, 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.)

7. 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 6. [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 to 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 of 0 to 4.

8. The chemically amplified resist composition according to any one of Claims 1 to 7, 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 acid anhydride (—C(═O)—O—C(═O)—).)

9. The chemically amplified resist composition according to any one of Claims 1 to 8, further containing a photoacid generator.

10. The chemically amplified resist composition according to any one of Claims 1 to 9, further containing a surfactant.

11. 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 10, a step of exposing the resist film to high energy rays, and a step of developing the exposed resist film using a developer.

12. The pattern forming method according to claim 11, wherein the high energy rays are i-line, KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet rays having a wavelength of 3 to 15 nm.

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