Onium salt type monomer, polymer, chemically amplified resist composition, and patterning method

Abstract

To provide an onium salt monomer used for a chemical amplification resist composition good in sensitivity and contrast, excellent in lithography characteristics such as exposure tolerance, edge roughness, dimensional uniformity, and focal depth, and strong in pattern collapse in fine pattern formation and excellent also in etching resistance in photolithography using a high energy ray, a polymer including a repeating unit derived from the onium salt type monomer, a chemical amplification resist composition including the polymer, and a method of forming pattern using the chemical amplification resist composition.SOLUTION: An onium salt type monomer is represented by the following formula (a1).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to onium salt type monomers, polymers, chemically amplified resist compositions, and patterning methods. [Background technology]

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern rules is progressing rapidly. In particular, the expansion of the flash memory market and the increase in storage capacity are driving this miniaturization. As for the most advanced miniaturization technology, mass production of 65nm node devices using ArF lithography is underway, and preparations for mass production of next-generation 45nm node devices using ArF immersion lithography are underway. For next-generation 32nm node devices, immersion lithography using ultra-high NA lenses combining a liquid with a higher refractive index than water, a high refractive index lens, and a high refractive index resist film, extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm, and double exposure (double patterning lithography) of ArF lithography are among the candidates and are currently being investigated.

[0003] As miniaturization progresses and approaches the diffraction limit of light, the contrast of light decreases. This decrease in light contrast leads to a reduction in the resolution of hole patterns and trench patterns, as well as a decrease in the focus margin, in positive resist films.

[0004] As patterns become finer, the edge roughness (LWR) of line patterns and the dimensional uniformity (CDU) of hole patterns are becoming problematic. The effects of uneven distribution and aggregation of base polymers and acid generators, as well as the effects of acid diffusion, have been pointed out. Furthermore, LWR tends to increase as the resist film thins, and the degradation of LWR due to thinning as finer patterns progress is becoming a serious problem.

[0005] In resist compositions for EUV lithography, it is necessary to simultaneously achieve high sensitivity, high resolution, and low LWR. Shortening the acid diffusion distance reduces LWR but also lowers sensitivity. For example, lowering the post-exposure bake (PEB) temperature reduces LWR but lowers sensitivity. Increasing the amount of quencher added also reduces LWR but lowers sensitivity. It is necessary to overcome the trade-off relationship between sensitivity and LWR.

[0006] To suppress acid diffusion, resist compounds containing repeating units derived from onium salts of polymerizable unsaturated sulfonic acids have been proposed (Patent Document 1). Such so-called polymer-bound acid generators have the characteristic of very short acid diffusion because polymer-type sulfonic acids are generated upon exposure. Furthermore, sensitivity can be improved by increasing the ratio of the acid generator. In the case of additive-type acid generators, increasing the amount added also increases sensitivity, but in this case the acid diffusion distance also increases. Since acids diffuse non-uniformly, increased acid diffusion degrades LWR and CDU. Polymer-type acid generators can be said to have high capability in balancing sensitivity, LWR, and CDU.

[0007] With the recent miniaturization of resist patterns, conventional resist compounds containing repeating units derived from onium salts of polymerizable unsaturated sulfonic acids present challenges in resist pattern collapse due to the developer during development and etching resistance after pattern formation. Furthermore, more sophisticated control of acid diffusion is required. To ensure the resolution of fine patterns, it is necessary to overcome these challenges simultaneously. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Patent No. 4425776 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] In acid-catalyzed chemically amplified resist compositions, there is a need for the development of a resist composition that exhibits good sensitivity, improves the LWR of lines and the CDU of holes, and also has excellent etching resistance after pattern formation.

[0010] The present invention has been made in view of the above circumstances, and aims to provide an onium salt type monomer used in a chemically amplified resist composition that exhibits good sensitivity and contrast, excellent lithography performance such as exposure margin (EL), LWR, CDU, and depth of focus (DOF) in photolithography using high-energy beams such as KrF excimer laser light, ArF excimer laser light, electron beam (EB), and EUV, and is also resistant to pattern deformation and etching even in the formation of fine patterns; a polymer containing repeating units derived from the onium salt type monomer; a chemically amplified resist composition containing the polymer; and a method for forming a pattern using the chemically amplified resist composition. [Means for solving the problem]

[0011] As a result of diligent research to achieve the above objective, the present inventors have discovered that by using a polymer containing repeating units derived from an onium salt containing a fluorosulfonic acid anion having acenaphthylene, a fused aromatic compound, as a polymer-bonded acid generator, a chemically amplified resist composition can be obtained that exhibits good sensitivity, improved LWR and CDU due to highly controlled acid diffusion, high contrast and high resolution, and excellent etching resistance, thus completing the present invention.

[0012] In other words, the present invention provides the following onium salt type monomers, polymers, chemically amplified resist compositions, and pattern forming methods. 1. An onium salt type monomer represented by the following formula (a1). [ka] (In the formula, n1 is an integer between 0 and 4. n2 is an integer between 0 and 4.) R A is, independently of one another, a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 1 is a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. When n1 ≧ 2, a plurality of R 1 may combine with each other to form a ring together with the carbon atom to which they are attached. L A and L B are, independently of one another, a single bond, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a carbonate bond or a carbamate bond. X L is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a hetero atom. Q 1 and Q 2 are, independently of one another, a hydrogen atom, a fluorine atom, a hydrocarbyl group having 1 to 6 carbon atoms or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Q 3 and Q 4 are, independently of one another, a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Z + is an onium cation.) 2. An onium salt type monomer represented by the following formula (a1-1).

Chemical formula

Chemical formula

[0013] A resist film containing a polymer comprising repeating units derived from an onium salt type monomer represented by formula (a1) has good solvent solubility, It has an asenaphthylene structure Therefore, it has the characteristic of low acid diffusion. This prevents a decrease in resolution due to blurring caused by acid diffusion, and makes it possible to improve LWR and CDU. 。 Furthermore, the aromatic ring acts as a good etching-resistant group, making it suitable for forming fine patterns. [Modes for carrying out the invention]

[0014] [Onium salt type monomer] The onium salt type monomer of the present invention is represented by the following formula (a1). [ka]

[0015] formula( a 1) Wherein, n1 is an integer between 0 and 4, but is preferably an integer between 0 and 2, and more preferably 0 or 1. n2 is an integer between 0 and 4, but is preferably an integer between 0 and 2, and more preferably 0 or 1.

[0016] formula( a 1) Medium, R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Of these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0017] formula( a 1) Medium, R 1This is a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom. Examples of the halogen atom include fluorine, chlorine, bromine, and iodine. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl groups; and cyclopropyl Cyclic saturated hydrocarbyl groups with 3 to 20 carbon atoms, such as pyr group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group; alkenyl groups with 2 to 20 carbon atoms, such as vinyl group, allyl group, propenyl group, butenyl group, hexenyl group; cyclic unsaturated hydrocarbyl groups with 3 to 20 carbon atoms, such as cyclohexenyl group; phenyl group, naphthyl group, etc. 6 Examples include aryl groups with up to 20 carbon atoms; aralkyl groups with 7 to 20 carbon atoms such as benzyl groups, 1-phenylethyl groups, and 2-phenylethyl groups; and groups obtained by combining these. Of these, aryl groups are preferred. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the inclusion of hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0018] When n1 ≥ 2, multiple R 1However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. Examples of rings formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornane rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., and as a result, the ring may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides, haloalkyl groups, etc.

[0019] formula( a 1) Medium, L A and L B These are, independently, a single bond, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a carbonate bond, or a carbamate bond. Of these, a single bond, an ether bond, or an ester bond is preferred.

[0020] formula( a 1) Medium, X L This is a 1-40 carbon atom hydrocarbylene group which may contain single bonds or heteroatoms. The hydrocarbylene group may be linear, branched, or cyclic, and specific examples include an alkanediyl group and a cyclic saturated hydrocarbylene group. The heteroatoms may include oxygen atoms, nitrogen atoms, sulfur atoms, etc.

[0021] X L The following are preferred as C1-C40 hydrocarbylene groups that may contain heteroatoms represented by the formula below. In the formula below, * represents L A and L B This represents a combination of two things. [ka]

[0022] [ka]

[0023] [ka]

[0024] Of these, X L -0~X L -3, X L -29~X L -34, X L -47~X L -49 is preferred, X L -0~X L -2, X L -29, X L -47 is more preferable.

[0025] formula( a 1) Medium, Q 1 and Q 2 Each of these is independently a hydrogen atom, a fluorine atom, a C1-C6 hydrocarbyl group, or a C1-C6 fluorinated saturated hydrocarbyl group. The C1-C6 hydrocarbyl group is R 1 Examples of fluorinated saturated hydrocarbyl groups having 1 to 20 carbon atoms, as represented by [formula], include those having 1 to 6 carbon atoms, but are not limited to these. A trifluoromethyl group is preferred as the fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms.

[0026] formula( a 1) Medium, Q 3 and Q 4 Each of these is independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. A trifluoromethyl group is preferred as the fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Q 3 and Q 4 It is even more preferable that the atom is a fluorine atom.

[0027] In formula ( a 1), n2 is an integer from 0 to 4. Among these, n2 is preferably from 0 to 2, and more preferably 0 or 1.

[0028] In formula ( a 1), -[C(Q 1 )(Q 2 )] n2 -C(Q 3 )(Q 4 )-SO3 - Specific examples of the partial structure represented by are preferably those shown below, but are not limited thereto. In the following formulas, * represents a bond with L B .

Chemical Formula

[0029] Among these, Acid-1 to Acid-7 are preferred, and Acid-1 to Acid-3, Acid-6 and Acid-7 are more preferred.

[0030] As the onium salt type monomer represented by formula (a1), those represented by the following formula (a1-1) are preferred

Chemical Formula

[0031] As the onium salt type monomer represented by formula (a1-1), those represented by the following formula (a1-2) are preferred.

Chemical Formula

[0032] Examples of the anion of the onium salt type monomer represented by the formula (a1) include, but are not limited to, the following. In the following formula, R A and Q 1 are the same as above. Also, the bonding positions of various substituents on the aromatic ring may be interchanged with each other.)

Chemical formula

[0033]

Chemical formula

[0034]

Chemical formula

[0035]

Chemical formula

[0036]

Chemical formula

[0037]

Chemical formula

[0038]

Chemical formula

[0039]

Chemical formula

[0040] formula( a 1) Medium, Z + This is an onium cation. The onium cation is preferably a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2). [ka]

[0041] In formulas (cation-1) and (cation-2), R ct1 ~R ct5 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom.

[0042] Examples of the halogen atoms mentioned above include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0043] The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C30 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups; C3-C30 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; C2-C30 alkenyl groups such as vinyl, allyl, propenyl, butenyl, and hexenyl groups; C3-C30 cyclic unsaturated hydrocarbyl groups such as cyclohexenyl groups; C6-C30 aryl groups such as phenyl, naphthyl, and thienyl groups; C7-C30 aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these, but aryl groups are preferred. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, the material may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0044] Also, R ct1 and R ct2 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, examples of sulfonium cations represented by formula (cation-1) include those represented by the following formula. [ka] (In the formula, the dashed line represents R ct3 (This is a combination of the two.)

[0045] Examples of sulfonium cations represented by formula (cation-1) include, but are not limited to, those listed below. [ka]

[0046] [ka]

[0047] [ka]

[0048] [ka]

[0049] [ka]

[0050] [ka]

[0051] [ka]

[0052] [ka]

[0053] [ka]

[0054] [ka]

[0055]

change

[0056]

change

[0057]

change

[0058]

change

[0059]

change

[0060]

change

[0061]

change

[0062]

change

[0063]

change

[0064]

change

[0065]

change

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] Examples of iodonium cations represented by formula (cation-2) include, but are not limited to, those listed below. [ka]

[0072] [ka]

[0073] Specific examples of onium salt monomers represented by formula (a1) include any combination of the anion and cation mentioned above.

[0074] The onium salt type monomer represented by formula (a1) can be synthesized, for example, by the same method as the sulfonium salt having polymerizable anion described in Japanese Patent Publication No. 5201363, but is not limited thereto.

[0075] formula( a 1) Represented by These onium salt type monomers are useful as photoacid generators bonded to the polymer main chain.

[0076] [polymer] The polymer of the present invention contains repeating units derived from an onium salt type monomer represented by formula (a1) (hereinafter also referred to as repeating unit a).

[0077] The polymer of the present invention is a polymer-bonded photoacid generator that functions as both a photoacid generator and a base polymer in a chemically amplified resist composition. A structural feature of the polymer of the present invention is that it has an acenaphthylene structure as a polymerizable group. Acenaphthylene is a polycyclic aromatic hydrocarbon that possesses both rigidity and polymerizability. Because it has an aromatic ring directly attached to the main chain, the main chain of the base polymer becomes rigid, thereby improving the glass transition temperature (Tg) of the base polymer. By introducing such an acenaphthylene structure into the main chain of the polymer as an anion of the photoacid generator, excessive acid diffusion of the generated acid after exposure is suppressed. Furthermore, it is conceivable that the base polymer will be arranged regularly due to the interaction of aromatic rings within or between base polymers (π-π stacking effect), resulting in resistance to pattern collapse in the developer even during fine pattern formation. Moreover, even in the etching process after fine pattern formation, the acenaphthylene structure provides excellent etching resistance. Due to these synergistic effects, the polymer of the present invention suppresses excessive acid diffusion, exhibits excellent LWR in line patterns and CDU in hole patterns, and enables pattern formation that is resistant to pattern collapse. Therefore, it is particularly suitable as a material for chemically amplified positive resist compositions.

[0078] The polymer may further contain a repeating unit represented by the following formula (b1) (hereinafter also referred to as repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit b2). [ka]

[0079] In equations (b1) and (b2), R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0080] In formula (b1), X 1 This consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-OX. 11 - or *-C(=O)-NH-X 11 -The phenylene group or naphthylene group may be substituted with a carbon-1 to carbon-10 alkoxy group or halogen atom, which may contain a fluorine atom. 11 This is a saturated hydrocarbylene group, phenylene group, or naphthylene group having 1 to 10 carbon atoms, and the saturated hydrocarbylene group may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. * represents a bond with a carbon atom of the main chain.

[0081] In formula (b2), X 2 The bond is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond with a carbon atom in the main chain. 11 This is a C1-C20 hydrocarbyl group which may contain a halogen atom, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyl group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. a is an integer from 0 to 4, preferably 0 or 1.

[0082] In formulas (b1) and (b2), AL 1 and AL 2 Each of these is independently an acid-unstable group. Examples of such acid-unstable groups include, but are not limited to, those described in Japanese Patent Publication No. 2013-80033 and Japanese Patent Publication No. 2013-83821.

[0083] Typically, the acid-unstable groups mentioned above are those represented by the following formulas (AL-1) to (AL-3). [ka] (In the formula, * represents a coupling.)

[0084] In equations (AL-1) and (AL-2), R L1 and R L2 Each of these is independently a hydrocarbyl group having 1 to 40 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. The hydrocarbyl group may be linear, branched, or cyclic. Hydrocarbyl groups having 1 to 20 carbon atoms are preferred.

[0085] In formula (AL-1), b is an integer between 0 and 10, preferably between 1 and 5.

[0086] In formula (AL-2), R L3 and R L4 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, or iodine atoms. The hydrocarbyl group may be linear, branched, or cyclic. Also, R L2 , R L3 and R L4 Any two of these may bond with each other to form a ring having 3 to 20 carbon atoms, together with the carbon atom to which they are bonded, or a carbon atom and an oxygen atom. The ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0087] In formula (AL-3), R L5 , R L6 and R L7 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. The hydrocarbyl group may be linear, branched, or cyclic. Also, R L5 , R L6 and RL7 Any two of them may combine with each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they are attached. As said ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0088] Examples of the repeating unit b1 include, but are not limited to, those shown below. In the following formulas, R A and AL 1 are the same as described above.

Chemical formula

[0089]

Chemical formula

[0090]

Chemical formula

[0091]

Chemical formula

[0092]

Chemical formula

[0093]

Chemical formula

[0094]

Chemical formula

[0095] Examples of the repeating unit b2 include, but are not limited to, those shown below. In the following formulas, R A and AL 2 are the same as described above. [ka]

[0096] [ka]

[0097] [ka]

[0098] Preferably, the base polymer further contains a repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit c). [ka]

[0099] In formula (c1), R A This is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 The bond is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond with a carbon atom in the main chain. 21 c is an integer from 1 to 20 carbon atoms, which may contain a halogen atom, a nitro group, a cyano group, a heteroatom, a hydrocarbyl group from 1 to 20 carbon atoms, a hydrocarbyloxy group from 1 to 20 carbon atoms, which may contain a heteroatom, a hydrocarbylcarbonyl group from 2 to 20 carbon atoms, which may contain a heteroatom, or a hydrocarbyloxycarbonyl group from 2 to 20 carbon atoms, which may contain a heteroatom. c is an integer from 1 to 4. d is an integer from 0 to 3, where 1 ≤ c + d ≤ 5.

[0100] The repeating unit c can be, but is not limited to, those listed below. Note that in the following formula, R A This is the same as described above. [ka]

[0101]

Chem.

[0102]

Chem.

[0103]

Chem.

[0104]

Chem.

[0105] The base polymer preferably further contains a repeating unit represented by the following formula (d1) (hereinafter also referred to as repeating unit d).

Chem.

[0106] In formula (d1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Z 1 is a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-Z 11 - or *-C(=O)-NH-Z 11 -, or the phenylene group or naphthylene group may be substituted with an alkoxy group having 1 to 10 carbon atoms or a halogen atom which may contain a fluorine atom. Z 11 is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated hydrocarbylene group may contain a hydroxy group, an ether bond, an ester bond or a lactone ring. * represents a bond to a carbon atom of the main chain. R 31This refers to a group having 1 to 20 carbon atoms that includes at least one structure selected from a hydrogen atom, or a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl 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)-OC(=O)-).

[0107] The repeating unit d can be, but is not limited to, the following. Note that in the following formula, R A This is the same as described above. [ka]

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] [ka]

[0113] [ka]

[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] [ka]

[0118] [ka]

[0119] [ka]

[0120] [ka]

[0121] [ka]

[0122] [ka]

[0123] As for the repeating unit c or d, in ArF lithography, those having a lactone ring are particularly preferred, and in KrF lithography, EB lithography, and EUV lithography, those having a phenol moiety are preferred.

[0124] The polymer may further contain repeating units (hereinafter also referred to as repeating unit e) having a structure in which a hydroxyl group is protected by an acid-unstable group. The repeating unit e is not particularly limited as long as it has one or more structures in which a hydroxyl group is protected and the protecting group decomposes upon the action of an acid to generate a hydroxyl group, but it is preferably represented by the following formula (e1). [ka]

[0125] In formula (e1), R A R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 41 R is a (e+1) valent hydrocarbon group having 1 to 30 carbon atoms, which may contain heteroatoms. 42 is an acid-unstable group. e is an integer between 1 and 4.

[0126] In formula (e1), R 42 The acid-unstable group represented by can be any group that is deprotected by the action of an acid and generates a hydroxyl group. 42 The structure is not particularly limited, but acetal structures, ketal structures, alkoxycarbonyl groups, and alkoxymethyl groups represented by the following formula (e2) are preferred, and alkoxymethyl groups represented by the following formula (e2) are particularly preferred. [ka] (In the formula, * represents a bond. R 43 (This refers to a hydrocarbyl group with 1 to 15 carbon atoms.)

[0127] R 42 Specific examples of the acid-unstable group represented by (e2), the alkoxymethyl group represented by (e2), and the repeating unit e are the same as those exemplified in the description of the repeating unit d described in Japanese Patent Application Publication No. 2020-111564.

[0128] The base polymer may further contain a repeating unit f derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or derivatives thereof. Examples of the monomer that gives the repeating unit f include, but are not limited to, those shown below. [Chemical formula]

[0129] The base polymer may further contain a repeating unit g derived from styrene, indane, vinyl pyridine or vinyl carbazole.

[0130] In the polymer of the present invention, the content ratios of the repeating units a, b1, b2, c, d, e, f and g are preferably 0 < a ≤ 0.4, 0 < b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 < c ≤ 0.6, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.3, 0 ≤ f ≤ 0.3 and 0 ≤ g ≤ 0.3, and more preferably 0 < a ≤ 0.3, 0 < b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 < c ≤ 0.5, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.2, 0 ≤ f ≤ 0.2 and 0 ≤ g ≤ 0.2. However, a + b1 + b2 + c + d + e + f + g ≤ 1.0.

[0131] The weight average molecular weight (Mw) of the polymer is preferably from 1000 to 500000, more preferably from 3000 to 100000. If Mw is within this range, sufficient etching resistance can be obtained and there is no risk of deterioration of the 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 tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent.

[0132] Furthermore, the molecular weight distribution (Mw / Mn) of the polymer tends to have a greater influence as the pattern rule becomes finer. Therefore, in order to obtain a resist composition suitable for fine pattern dimensions, it is preferable that the Mw / Mn is narrowly dispersed between 1.0 and 2.0. Within this range, there are few low molecular weight or high molecular weight polymers, and there is no risk of foreign matter being observed on the pattern or deterioration of the pattern shape after exposure.

[0133] One example of a method for synthesizing the aforementioned polymer is to heat a monomer that provides the repeating units described above in an organic solvent with a radical polymerization initiator added, and polymerize it.

[0134] Examples of organic solvents used during polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyrolactone (GBL). Examples of polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of these initiators added is preferably 0.01 to 25 mol% of the total amount of monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, and more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the viewpoint of production efficiency.

[0135] The polymerization initiator may be added to the monomer solution and supplied to the reaction vessel, or an initiator solution may be prepared separately from the monomer solution and each supplied to the reaction vessel independently. Since the polymerization reaction may proceed and a superpolymer may be formed by radicals generated from the initiator during the waiting time, it is preferable from a quality control viewpoint to prepare the monomer solution and the initiator solution independently and add them dropwise. The acid-unstable group may be used as is, introduced into the monomer, or it may be protected or partially protected after polymerization. In addition, known chain transfer agents such as dodecyl mercaptan or 2-mercaptoethanol may be used in combination to adjust the molecular weight. In this case, the amount of these chain transfer agents added is preferably 0.01 to 20 mol% of the total amount of monomers to be polymerized.

[0136] In the case of monomers containing hydroxyl groups, the hydroxyl groups may be substituted with acetal groups that are easily deprotected by acids such as ethoxyethoxy groups during polymerization, and then deprotected with a weak acid and water after polymerization. Alternatively, they may be substituted with acetyl groups, formyl groups, pivaloyl groups, etc., and then alkaline hydrolysis may be performed after polymerization.

[0137] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene may be polymerized by heating in an organic solvent with a radical polymerization initiator. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene may be used, and after polymerization, the acetoxy group may be deprotected by alkaline hydrolysis to obtain polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0138] Ammonia water, triethylamine, etc., can be used as the base during alkaline hydrolysis. 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.

[0139] The amount of each monomer in the monomer solution can be appropriately set, for example, to achieve a preferred content ratio of the repeating units described above.

[0140] The polymer obtained by the above manufacturing method may be treated as a final product if it is a reaction solution obtained by a polymerization reaction, or as a final product if it is a powder obtained by a purification process such as a reprecipitation method in which the polymerization solution is added to a poor solvent and a powder is obtained. However, from the viewpoint of work 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.

[0141] Specific examples of solvents used in this process include ketones such as cyclohexanone and methyl-2-n-pentyl ketone, as described in paragraphs

[0144] to

[0145] of Japanese Patent Publication No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; 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. Examples include ethers such as ethers; 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; alcohols such as diacetone alcohol (DAA); high-boiling point alcoholic solvents such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol; and mixed solvents thereof.

[0142] In the polymer solution, the concentration of the polymer is preferably 0.01 to 30% by mass, and more preferably 0.1 to 20% by mass.

[0143] It is preferable to filter the reaction solution or polymer solution. Filtering removes foreign matter and gel that may cause defects, which is effective in stabilizing quality.

[0144] Examples of filter materials used in the aforementioned filter filtration include fluorocarbon, cellulose, nylon, polyester, and hydrocarbon materials. However, in the filtration process of chemically amplified resist compositions, filters made of fluorocarbon materials such as Teflon (registered trademark), hydrocarbon materials such as polyethylene and polypropylene, or nylon are preferred. The pore size of the filter can be appropriately selected according to the desired level of cleanliness, but is preferably 100 nm or less, and more preferably 20 nm or less. These filters may be used individually or in combination. The filtration method may involve passing the solution through only once, but it is more preferable to circulate the solution and filter it multiple times. The filtration process can be carried out in any order and number of times in the polymer manufacturing process, but it is preferable to filter the reaction solution after the polymerization reaction, the polymer solution, or both.

[0145] [Chemically amplified resist composition] [(A) Base polymer] The chemically amplified resist composition of the present invention includes a base polymer containing the aforementioned polymer as component (A).

[0146] The aforementioned polymer may be used alone, or two or more polymers with different composition ratios, Mw, and / or Mw / Mn may be used in combination. In addition, the (A) base polymer may include hydrogenated ring-opening metathesis polymers in addition to the aforementioned polymers, and for this, those described in Japanese Patent Publication No. 2003-66612 may be used.

[0147] [(B) Organic solvents] The chemically amplified resist composition of the present invention may contain an organic solvent as component (B). The organic solvent (B) is not particularly limited as long as it is capable of dissolving the components described above and the components described later. Examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; keto alcohols 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.

[0148] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixed solvents thereof are preferred, as they exhibit particularly excellent solubility of the base polymer of component (A).

[0149] In the chemically amplified resist composition of the present invention, the content of (B) organic solvent is preferably 200 to 5000 parts by mass, and more preferably 400 to 3500 parts by mass, per 80 parts by mass of (A) base polymer. (B) organic solvent may be used alone or as a mixture of two or more types.

[0150] [(C) Quencher] The chemically amplified resist composition of the present invention may contain a quencher as component (C). In this invention, a quencher is a material that traps the acid generated from the photoacid generator in the chemically amplified resist composition, thereby preventing its diffusion to unexposed areas and forming a desired pattern.

[0151] (C) Quenchers include onium salts represented by the following formulas (1) or (2). [ka]

[0152] In formula (1), R q1 This is a C1-C40 hydrocarbyl group which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the α-carbon of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group. In formula (2), R q2 This is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a hydrogen atom or a heteroatom.

[0153] R q1 Specifically, the C1-C40 hydrocarbyl groups represented by include C1-C40 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0 2,6Examples include cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as decyl groups and adamantyl groups; and aryl groups having 6 to 40 carbon atoms, such as phenyl groups, naphthyl groups, and anthracenyl groups. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, the group may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0154] R q2 Specifically, the hydrocarbyl group represented by R q1 In addition to the substituents exemplified as specific examples, other examples include fluorinated saturated hydrocarbyl groups such as trifluoromethyl and trifluoroethyl groups, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl groups.

[0155] The anions of the onium salt represented by formula (1) include, but are not limited to, those listed below. [ka]

[0156] [ka]

[0157] [ka]

[0158] The anions of the onium salt represented by formula (2) include, but are not limited to, those listed below. [ka]

[0159] [ka]

[0160] [ka]

[0161] In equations (1) and (2), MQ + This is an onium cation. The onium cation is preferably a sulfonium cation represented by the formula (cation-1) described above, an iodonium cation represented by the formula (cation-2) described above, or an ammonium cation represented by the following formula (cation-3). [ka]

[0162] In formula (cation-3), R ct6 ~R ct9 Each of these is independently a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. Also, R ct6 and R ct7 These may bond with each other to form a ring with the nitrogen atom to which they are bonded. The hydrocarbyl group is R in the description of formulas (cation-1) and (cation-2). ct1 ~R ct5 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0163] Examples of ammonium cations represented by formula (cation-3) include, but are not limited to, those listed below. [ka]

[0164] Specific examples of onium salts represented by formula (1) or (2) include any combination of the anions and cations mentioned above. These onium salts can be easily prepared by ion exchange reactions using known organic chemical methods. For ion exchange reactions, refer to, for example, Japanese Patent Publication No. 2007-145797.

[0165] 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 because each counteranion of the onium salt is a conjugate base of a weak acid. Here, a weak acid refers to an acidity that does not deprotect the acid-unstable groups of the acid-unstable group-containing units used in the base polymer. The onium salt represented by formula (1) or (2) functions as a quencher when used in combination with an onium salt type photoacid generator having a conjugate base of a strong acid, such as a sulfonic acid with fluorinated α-position, as a counteranion. That is, when an onium salt that generates a strong acid, such as a sulfonic acid with fluorinated α-position, is mixed with an onium salt that generates a weak acid, such as an unfluorinated sulfonic acid or carboxylic acid, 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, the weak acid is released by salt exchange, and an onium salt having a strong acid anion is produced. In this process, strong acids are replaced by weaker acids with lower catalytic activity, so the acids appear to be deactivated, allowing for control of acid diffusion.

[0166] Furthermore, as the (C) quencher, an onium salt having a sulfonium cation and a phenoxide anion moiety in the same molecule as described in Japanese Patent Publication No. 6848776, an onium salt having a sulfonium cation and a carboxylate anion moiety in the same molecule as described in Japanese Patent Publication No. 6583136 and Japanese Patent Application Publication No. 2020-200311, and an onium salt having an iodonium cation and a carboxylate anion moiety in the same molecule as described in Japanese Patent Publication No. 6274755 can also be used.

[0167] Here, if the photoacid generator that produces a strong acid is an onium salt, as mentioned above, the strong acid produced by high-energy ray irradiation can be exchanged for a weak acid. On the other hand, it is thought that the weak acid produced by high-energy ray irradiation is unlikely to collide with the unreacted onium salt that produces the strong acid and undergo salt exchange. This is due to the phenomenon that onium cations are more likely to form ion pairs with the anions of stronger acids.

[0168] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (1) or (2) as the (C) quencher, the content is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, per 80 parts by mass of the (A) base polymer. When the onium salt type quencher of component (C) is within the above range, the resolution is good and the sensitivity does not decrease significantly, which is preferable. The onium salt represented by formula (1) or (2) may be used alone or in combination of two or more types.

[0169] The chemically amplified resist composition of the present invention may contain a nitrogen-containing compound as the (C) quencher. Examples of the nitrogen-containing compound of component (C) include primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Publication No. 2008-111103, particularly amine compounds having a hydroxyl group, ether bond, ester bond, lactone ring, cyano group, or sulfonic acid ester bond. Also, examples include compounds in which a primary or secondary amine is protected with a carbamate group, such as the compound described in Japanese Patent Application Publication No. 3790649.

[0170] Furthermore, a sulfonium sulfonate salt having a nitrogen-containing substituent may be used as the nitrogen-containing compound. Such a compound functions as a quencher in the unexposed area and loses its quenching ability in the exposed area through neutralization with its own generated acid, functioning as a so-called photodecayable base. By using a photodecayable base, the contrast between the exposed and unexposed areas can be further enhanced. For example, Japanese Patent Publication No. 2009-109595 and Japanese Patent Publication No. 2012-46501 can be referenced as examples of photodecayable bases.

[0171] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as (C) quencher, the content is preferably 0.001 to 12 parts by mass, and more preferably 0.01 to 8 parts by mass, per 80 parts by mass of the (A) base polymer. The nitrogen-containing compound may be used alone or in combination of two or more types.

[0172] [(D) Acid Generator] The chemically amplified resist composition of the present invention may contain an acid generator, to the extent that it does not impair the effects of the present invention. Examples of the acid generator include compounds that generate acid in response to active light or radiation (photoacid generators). The photoacid generator is not particularly limited as long as it is a compound that generates acid upon irradiation with high-energy rays, but those that generate sulfonic acid, imido acid, or methidoic acid are preferred. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc. Specific examples of acid generators are those described in paragraphs

[0122] to

[0142] of Japanese Patent Application Publication No. 2008-111103.

[0173] Furthermore, sulfonium salts represented by the following formula (3-1) and iodonium salts represented by the following formula (3-2) can also be suitably used as photoacid generators. [ka]

[0174] In equations (3-1) and (3-2), R 101 ~R 105 Each of these is a hydrocarbyl group having 1 to 20 carbon atoms, which may independently contain a halogen atom or a heteroatom. In the description of formulas (cation-1) and (cation-2), R is used to describe the halogen atom and the hydrocarbyl group. ct1 ~R ct5Examples of halogen atoms and hydrocarbyl groups represented by are the same as those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc. 101 and R 102 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring formed is R as described in the explanation of formula (cation-1). ct1 and R ct2 Examples similar to those exemplified include rings that can be formed when these elements bond to each other, together with the sulfur atoms to which they bond.

[0175] Examples of cations for the sulfonium salt represented by formula (3-1) are the same as those exemplified for the sulfonium cation represented by formula (cation-1). Similarly, examples of cations for the iodonium salt represented by formula (3-2) are the same as those exemplified for the iodonium cation represented by formula (cation-2).

[0176] In equations (3-1) and (3-2), Xa - This is an anion selected from the following formulas (3A) to (3D). [ka]

[0177] In formula (3A), R faR is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (3A') described later. fa1 Examples similar to those given in the explanation can be cited.

[0178] The anion represented by formula (3A) is preferably the one represented by formula (3A') below. [ka]

[0179] In formula (3A'), R HF This is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0180] In formula (3A'), R fa1 This is a hydrocarbyl group having 1 to 38 carbon atoms, which may contain heteroatoms. The heteroatoms are preferably oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc., with oxygen atoms being more preferred. From the viewpoint of obtaining high resolution in fine pattern formation, the hydrocarbyl group having 6 to 30 carbon atoms is particularly preferred.

[0181] R fa1The C1-C38 hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C38 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and eicosyl; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl Examples include cyclic saturated hydrocarbyl groups with 3 to 38 carbon atoms, such as C3, norbornylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated aliphatic hydrocarbyl groups with 2 to 38 carbon atoms, such as allyl and 3-cyclohexenyl; aryl groups with 6 to 38 carbon atoms, such as phenyl, 1-naphthyl, and 2-naphthyl; aralkyl groups with 7 to 38 carbon atoms, such as benzyl and diphenylmethyl; and groups obtained by combining these.

[0182] Furthermore, 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, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a 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)-OC(=O)-), a haloalkyl group, etc. Of the heteroatoms, oxygen atoms are preferred. Examples of hydrocarbyl groups containing heteroatoms include tetrahydrofuryl group, methoxymethyl group, ethoxymethyl group, methylthiomethyl group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy)methyl group, acetoxymethyl group, 2-carboxy-1-cyclohexyl group, 2-oxopropyl group, 4-oxo-1-adamantyl group, and 3-oxocyclohexyl group.

[0183] For details on the synthesis of sulfonium salts containing the anion represented by formula (3A'), please refer to Japanese Patent Publication No. 2007-145797, Japanese Patent Publication No. 2008-106045, Japanese Patent Publication No. 2009-7327, Japanese Patent Publication No. 2009-258695, etc. Also, sulfonium salts described in Japanese Patent Publication No. 2010-215608, Japanese Patent Publication No. 2012-41320, Japanese Patent Publication No. 2012-106986, Japanese Patent Publication No. 2012-153644, etc., can be suitably used.

[0184] The anions represented by formula (3A) include, but are not limited to, those listed below. In the formula below, Ac represents an acetyl group. [ka]

[0185] [ka]

[0186] [ka]

[0187] [ka]

[0188] In formula (3B), R fb1 and R fb2 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (3A'). fa1 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fb1 and R fb2 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms.fb1 and R fb2 This refers to the groups that bond to each other (-CF2-SO2-N - It may form a ring with -SO2-CF2-), in which case R fb1 and R fb2 The group obtained by the bonding of these two elements is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0189] In formula (3C), R fc1 , R fc2 and R fc3 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (3A'). fa1 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fc1 , R fc2 and R fc3 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 This refers to the groups that bond to each other (-CF2-SO2-C - It may form a ring with -SO2-CF2-), in which case R fc1 and R fc2 The group obtained by the bonding of these two elements is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0190] In formula (3D), R fd R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (3A'). fa1 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown.

[0191] The synthesis of sulfonium salts containing the anion represented by formula (3D) is detailed in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2014-133723.

[0192] The anions represented by formula (3D) include, but are not limited to, those listed below. [ka]

[0193] [ka]

[0194] Furthermore, the photoacid generator containing the anion represented by formula (3D) does not have a fluorine atom at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position, which gives it sufficient acidity to cleave acid-unstable groups in the base polymer. Therefore, it can be used as a photoacid generator.

[0195] As a photoacid generator, one represented by the following formula (4) can also be suitably used. [ka]

[0196] In formula (4), R 201 and R 202 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain heteroatoms. 203 This is a hydrocarbylene group having 1 to 30 carbon atoms, which may contain heteroatoms. Also, R 201 , R 202 and R 203 Any two of these may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is defined as R in the explanation of formula (cation-1). ct1 and R ct2Examples similar to those exemplified include rings that can be formed when these elements bond to each other, together with the sulfur atoms to which they bond.

[0197] R 201 and R 202 The C1-C30 hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C30 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, and tricyclo[5.2.1.0 2,6 Examples include cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as decyl groups and adamantyl groups; aryl groups having 6 to 30 carbon atoms, such as phenyl groups, methylphenyl groups, ethylphenyl groups, n-propylphenyl groups, isopropylphenyl groups, n-butylphenyl groups, isobutylphenyl groups, sec-butylphenyl groups, tert-butylphenyl groups, naphthyl groups, methylnaphthyl groups, ethylnaphthyl groups, n-propylnaphthyl groups, isopropylnaphthyl groups, n-butylnaphthyl groups, isobutylnaphthyl groups, sec-butylnaphthyl groups, tert-butylnaphthyl groups, anthracenyl groups, and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, the material may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0198] R 203The hydrocarbylene group, represented by , having 1 to 30 carbon atoms, may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkane diyl groups with 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, etc.; cyclopentanediyl group, cyclohex Examples include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as xanediyl, norbornanediyl, and adamantanediyl groups; arylene groups having 6 to 30 carbon atoms, such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, and tert-butylnaphthylene; and groups obtained by combining these. Furthermore, 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, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, 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)-OC(=O)-), a haloalkyl group, etc. The heteroatom is preferably an oxygen atom.

[0199] In formula (4), LA This is a 1-20 carbon atom hydrocarbylene group which may contain single bonds, ether bonds, or heteroatoms. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 203 Examples of hydrocarbylene groups represented by the same formula as those exemplified above include the same groups as those shown.

[0200] In formula (4), X A , X B , X C and X D Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. However, X A , X B , X C and X D At least one of these is a fluorine atom or a trifluoromethyl group.

[0201] In equation (4), k is an integer between 0 and 3.

[0202] The photoacid generator represented by formula (4) is preferably the one represented by formula (4') below. [ka]

[0203] In formula (4'), L A This is the same as above. R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (3A'). fa1 Examples of hydrocarbyl groups represented by the formula shown are similar to those exemplified. x and y are each independent integers from 0 to 5. z is an integer from 0 to 4.

[0204] Examples of photoacid generators represented by formula (4) include those similar to those exemplified as photoacid generators represented by formula (2) in Japanese Patent Publication No. 2017-26980.

[0205] Among the photoacid generators, those containing an anion represented by formula (3A') or (3D) are particularly preferred because they exhibit low acid diffusion and excellent solubility in solvents. Furthermore, those represented by formula (4') are particularly preferred because they exhibit extremely low acid diffusion.

[0206] In addition, sulfonium salts and iodonium salts containing anions having an aromatic ring substituted with an iodine atom, represented by the following formulas (5-1) or (5-2), can also be used as other acid generators. [ka]

[0207] In equations (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, and more preferably 2 or 3. r is preferably an integer satisfying 0 ≤ r ≤ 2.

[0208] In equations (5-1) and (5-2), L 1 This is a saturated hydrocarbylene group having 1 to 6 carbon atoms, which may contain a single bond, an ether bond, or an ester bond, or an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0209] In equations (5-1) and (5-2), L 2 When p is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms, and when p is 2 or 3, it is a (p+1) valent linking group having 1 to 20 carbon atoms, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0210] In equations (5-1) and (5-2), R 401This may include a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group, or an ether bond, and may contain 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, or -N(R 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D Or -N(R 401C )-C(=O)-OR 401D That is. R 401A and R 401B Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 401C R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 401D This is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 They may be the same or different from one another.

[0211] Of these, R 401Examples include hydroxyl groups, -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-OR 401D Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc. are preferred.

[0212] In equations (5-1) and (5-2), Rf 11 ~Rf 14 Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of these is either a fluorine atom or a trifluoromethyl group. Also, Rf 11 and Rf 12 These may combine to form a carbonyl group. In particular, Rf 13 and Rf 14 It is preferable that both are fluorine atoms.

[0213] In equations (5-1) and (5-2), R 402 ~R 406 Each of these is a hydrocarbyl group having 1 to 20 carbon atoms, which may independently contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. For example, in the explanation of formulas (cation-1) and (cation-2), R ct1 ~R ct5 Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxyl group, carboxyl group, halogen atom, cyano group, nitro group, mercapto group, sultone ring, sulfo group, or sulfonium salt-containing group, and some of the -CH2- of the hydrocarbyl group may be substituted with an ether bond, ester bond, carbonyl group, amide bond, carbonate bond, or sulfonic acid ester bond. 402 and R 403 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is R as described in the explanation of formula (cation-1). ct1 and R ct2Examples similar to those exemplified include rings that can be formed when these elements bond to each other, together with the sulfur atoms to which they bond.

[0214] Examples of cations for the sulfonium salt represented by formula (5-1) are the same as those exemplified for the sulfonium cation represented by formula (cation-1). Similarly, examples of cations for the iodonium salt represented by formula (5-2) are the same as those exemplified for the iodonium cation represented by formula (cation-2).

[0215] The anions of the onium salt represented by formula (5-1) or (5-2) include, but are not limited to, those listed below. [ka]

[0216] [ka]

[0217] [ka]

[0218] [ka]

[0219] [ka]

[0220] [ka]

[0221] [ka]

[0222]

change

[0223]

change

[0224]

change

[0225]

change

[0226]

change

[0227]

change

[0228]

change

[0229]

change

[0230]

change

[0231]

change

[0232]

change

[0233] [ka]

[0234] [ka]

[0235] [ka]

[0236] [ka]

[0237] If the chemically amplified resist composition of the present invention contains (D) an acid generator, its content is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass, per 80 parts by mass of the (A) base polymer. When the amount of acid generator of component (D) is within the above range, the resolution is good and there is no risk of foreign matter problems occurring after development or peeling of the resist film, so it is preferable. (D) The acid generator may be used alone or in combination of two or more types.

[0238] [(E) Surfactants] The chemically amplified resist composition of the present invention may further contain a surfactant as component (E). Preferably, the surfactant (E) is a surfactant that is insoluble or sparingly soluble in water and soluble in an alkaline developer, or a surfactant that is insoluble or sparingly soluble in both water and an alkaline developer. Examples of such surfactants can be found in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2011-16746.

[0239] As surfactants that are insoluble or poorly soluble in water and alkaline developer, among the surfactants described in the above publication, FC-4430 (manufactured by 3M), Surflon® S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Orfin® E1004 (manufactured by Nisshin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and oxetane ring-opening polymers represented by the following formula (surf-1) are preferred. [ka]

[0240] Here, R, Rf, A, B, C, m, and n apply only to formula (surf-1), notwithstanding the preceding description. R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. Examples of such aliphatic groups include the divalent ethylene group, 1,4-butylene group, 1,2-propylene group, 2,2-dimethyl-1,3-propylene group, and 1,5-pentylene group, while examples of trivalent or tetravalent aliphatic groups are listed below. [ka] (In the formula, the dashed lines represent bonds, which are substructures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.)

[0241] Among these, the 1,4-butylene group and the 2,2-dimethyl-1,3-propylene group are preferred.

[0242] 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, 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. Furthermore, the order of each constituent unit in formula (surf-1) is not specified, and they may be bonded in a block-like manner or randomly. For details on the production of partially fluorinated oxetane ring-opening polymer surfactants, please refer to U.S. Patent No. 5,650,483, etc.

[0243] Surfactants that are insoluble or sparingly soluble in water and soluble in alkaline developers have the function of reducing water penetration and leaching by orienting themselves on the surface of the resist film when a resist protective film is not used in ArF immersion lithography. Therefore, they are useful in suppressing the elution of water-soluble components from the resist film and reducing damage to the exposure equipment. Furthermore, they are useful because they become solubilized during alkaline aqueous solution development after exposure or post-exposure bake (PEB) and are less likely to become foreign substances that cause defects. Such surfactants are insoluble or sparingly soluble in water and soluble in alkaline developers, and are polymer-type surfactants, also called hydrophobic resins, with those that have particularly high water repellency and improve water lubricity being preferred.

[0244] Examples of such polymer-type surfactants include those containing at least one repeating unit selected from the following formulas (6A) to (6E). [ka]

[0245] In formulas (6A) to (6E), R B is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 R is -CH2-, -CH2CH2-, -O-, or two separated -H atoms. s1Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. s2 R is a single bond or a linear or branched hydrocarbylene group having 1 to 5 carbon atoms. s3 Each of these is independently a hydrogen atom, a C1-C15 hydrocarbyl group or a fluorinated hydrocarbyl group, or an acid-unstable group. s3 If the group is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be interposed between the carbon-carbon bonds. s4 R is a (u+1) valent hydrocarbon group or fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer from 1 to 3. s5 These are, independently, hydrogen atoms, or -C(=O)-OR sa It is a group represented by R. sa This is a fluorinated hydrocarbyl group having 1 to 20 carbon atoms. s6 This is a hydrocarbyl group having 1 to 15 carbon atoms or a fluorinated hydrocarbyl group, and an ether bond or a carbonyl group may be interposed between the carbon-carbon bonds.

[0246] R s1 The C1-C10 hydrocarbyl group represented by is preferably a saturated hydrocarbyl group and may be linear, branched, or cyclic. Specific examples include C1-C10 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups; and C3-C10 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl groups. Of these, those with C1-C6 are preferred.

[0247] R s2 The hydrocarbylene group represented by is preferably a saturated hydrocarbylene group and may be linear, branched, or cyclic. Specific examples include methylene, ethylene, propylene, butylene, and pentylene groups.

[0248] R s3 or R s6 The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include saturated hydrocarbyl groups, alkenyl groups, alkynyl groups, and other aliphatic unsaturated hydrocarbyl groups, but saturated hydrocarbyl groups are preferred. The saturated hydrocarbyl group is R s1 In addition to the examples given as hydrocarbyl groups represented by , other examples include undecyl groups, dodecyl groups, tridecyl groups, tetradecyl groups, pentadecyl groups, etc. s3 or R s6 Examples of fluorinated hydrocarbyl groups represented by the above-mentioned hydrocarbyl group include groups in which some or all of the hydrogen atoms bonded to the carbon atoms are replaced with fluorine atoms. As mentioned above, ether bonds or carbonyl groups may be interposed between these carbon-carbon bonds.

[0249] R s3 Examples of acid-unstable groups represented by the formulas (AL-3) to (AL-5) mentioned above include trialkylsilyl groups in which each alkyl group has 1 to 6 carbon atoms, and oxo group-containing alkyl groups having 4 to 20 carbon atoms.

[0250] R s4 The (u+1) valent hydrocarbon group or fluorinated hydrocarbon group represented by can be linear, branched, or cyclic, and specific examples include groups obtained by further removing u hydrogen atoms from the aforementioned hydrocarbyl group or fluorinated hydrocarbyl group.

[0251] R saThe fluorinated hydrocarbyl group represented by is preferably saturated and may be linear, branched, or cyclic. Specific examples include those in which some or all of the hydrogen atoms of the hydrocarbyl group are substituted with fluorine atoms, and specific examples of such include 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, etc.

[0252] The repeating units represented by any of the formulas (6A) to (6E) include, but are not limited to, the following. Note that in the following formulas, R B This is the same as described above. [ka]

[0253] [ka]

[0254] [ka]

[0255] [ka]

[0256] [ka]

[0257] The polymer-type surfactant may further contain other repeating units other than those represented by formulas (6A) to (6E). Examples of other repeating units include those obtained from methacrylic acid and α-trifluoromethylacrylic acid derivatives. The content of the repeating units represented by formulas (6A) to (6E) in the polymer-type surfactant is preferably 20 mol% or more, more preferably 60 mol% or more, and even more preferably 100 mol% of the total repeating units.

[0258] The Mw of the polymer-type surfactant is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. The Mw / Mn ratio is preferably 1.0 to 2.0, and more preferably 1.0 to 1.6.

[0259] A method for synthesizing the polymer-type surfactant involves polymerizing a monomer containing unsaturated bonds that provide repeating units represented by formulas (6A) to (6E), and optionally other repeating units, by heating it in an organic solvent with a radical initiator. Examples of organic solvents used during polymerization include toluene, benzene, THF, diethyl ether, and dioxane. Examples of polymerization initiators include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. The acid-unstable group may be used as is after being introduced into the monomer, or it may be protected or partially protected after polymerization.

[0260] When synthesizing the polymer-type surfactant, known chain transfer agents such as dodecyl mercaptan or 2-mercaptoethanol may be used to adjust the molecular weight. In that case, the amount of these chain transfer agents added is preferably 0.01 to 10 mol% relative to the total number of moles of monomers to be polymerized.

[0261] If the chemically amplified resist composition of the present invention contains (E) a surfactant, its content is preferably 0.1 to 50 parts by mass, and more preferably 0.5 to 10 parts by mass, per 80 parts by mass of the (A) base polymer. If the content of (E) surfactant is 0.1 parts by mass or more, the receding contact angle between the resist film surface and water is sufficiently improved, and 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. (E) surfactant may be used alone or in combination of two or more types.

[0262] [(F) Dissolution inhibitor] The chemically amplified resist composition of the present invention may further contain a dissolution inhibitor as component (F). When the chemically amplified resist composition of the present invention is of the positive type, the difference in dissolution rate between the exposed and unexposed areas can be further increased by incorporating a dissolution inhibitor, thereby further improving the resolution.

[0263] Examples of the aforementioned dissolution inhibitors include compounds having a molecular weight of preferably 100 to 1000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule, in which the hydrogen atoms of the phenolic hydroxyl groups are substituted with acid-unstable groups in a proportion of 0 to 100 mol% overall, or compounds containing a carboxyl group in the molecule, in which the hydrogen atoms of the carboxyl group are substituted with acid-unstable groups in an average proportion of 50 to 100 mol overall. Specifically, examples include compounds in which the hydrogen atoms of the hydroxyl group or carboxyl group of bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalenecarboxylic acid, adamantanecarboxylic acid, and cholic acid are substituted with acid-unstable groups, for example, those described in paragraphs

[0155] to

[0178] of Japanese Patent Application Publication No. 2008-122932.

[0264] If the chemically amplified resist composition of the present invention contains (F) a dissolution inhibitor, its content is preferably 0 to 50 parts by mass, and more preferably 5 to 40 parts by mass, per 80 parts by mass of (A) the base polymer.

[0265] [(G) Other ingredients] The chemically amplified resist composition of the present invention may include, as (G) other components, compounds that decompose with acid to generate acid (acid-generating compounds), organic acid derivatives, fluorine-substituted alcohols, water-repellency enhancers, etc. As the acid-generating compounds, compounds described in Japanese Patent Publication No. 2009-269953 or Japanese Patent Publication No. 2010-215608 can be referenced. When the acid-generating compounds are included, their content is preferably 0 to 5 parts by mass, and more preferably 0 to 3 parts by mass, per 80 parts by mass of the (A) base polymer. If the content is too high, it becomes difficult to control acid diffusion, which may lead to deterioration of resolution and pattern shape. As the organic acid derivatives and fluorine-substituted alcohols, compounds described in Japanese Patent Publication No. 2009-269953 or Japanese Patent Publication No. 2010-215608 can be referenced.

[0266] The water-repellent enhancer can be used in immersion lithography without a topcoat. Preferred water-repellent enhancers include polymers containing alkyl fluoride, polymers containing 1,1,1,3,3,3-hexafluoro-2-propanol residues of a specific structure, and those exemplified in Japanese Patent Publication No. 2007-297590 and Japanese Patent Publication No. 2008-111103 are more preferred. The water-repellent enhancer needs to be soluble in an alkaline developer or an organic solvent developer. The aforementioned water-repellent enhancer having a specific 1,1,1,3,3,3-hexafluoro-2-propanol residue exhibits good solubility in the developer. As a water-repellent enhancer, polymers containing repeating units including amino groups or amine salts are highly effective in preventing acid evaporation in the PEB and thus preventing poor hole pattern opening after development. If the chemically amplified resist composition of the present invention contains the water-repellency improving agent, its content is preferably 0 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass, per 80 parts by mass of the (A) base polymer.

[0267] [Pattern formation method] When the chemically amplified resist composition of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied. For example, a pattern formation method may include a step of forming a resist film on a substrate using the chemically amplified resist composition described above, a step of exposing the resist film with high-energy rays, and a step of developing the exposed resist film using a developer.

[0268] First, the chemically amplified resist composition of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, so that the coating film thickness is 0.01 to 2.0 μm. This is then pre-baked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0269] Next, the resist film is exposed using high-energy rays. Examples of high-energy rays include ultraviolet rays, far-ultraviolet rays, EB rays, EUV rays with wavelengths of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When using ultraviolet rays, far-ultraviolet rays, EUV rays, X-rays, soft X-rays, excimer laser light, gamma rays, or synchrotron radiation as the high-energy rays, the exposure amount is preferably 1 to 200 mJ / cm², either directly or using a mask to form the desired pattern. 2 To the extent, more preferably 10 to 100 mJ / cm² 2 Irradiate to the extent of the above. When using EB as the high-energy beam, the exposure dose is preferably 0.1 to 100 μC / cm². 2 To a degree, more preferably 0.5 to 50 μC / cm² 2The pattern is drawn either directly or using a mask to form the desired pattern. The chemically amplified resist composition of the present invention is particularly suitable for fine patterning using high-energy rays, including ArF excimer laser light with a wavelength of 193 nm, KrF excimer laser light with a wavelength of 248 nm, EB, or EUV, X-rays, soft X-rays, gamma rays, or synchrotron radiation with wavelengths of 3 to 15 nm.

[0270] After exposure, PEB may be performed on a hot plate at a temperature of preferably 60-150°C for 10 seconds to 30 minutes, more preferably at 80-120°C for 30 seconds to 20 minutes.

[0271] After exposure or PEB, development is performed using a developer solution containing 0.1 to 10% by mass, preferably 2 to 5% by mass, of an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by conventional methods such as the dip method, puddle method, or spray method. The areas irradiated with light dissolve in the developer solution, while the areas not exposed do not dissolve, forming the desired positive-type pattern on the substrate.

[0272] Negative patterns can also be obtained using an organic solvent developer instead of the aforementioned alkaline aqueous solution. The developers used in this case 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 crotate, ethyl crotate, Examples include 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, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenyl acetate, and 2-phenylethyl acetate. These organic solvents may be used individually or in mixtures of two or more.

[0273] Rinsing may be performed at the end of development. A solvent that mixes with the developer but does not dissolve the resist film is preferred as the rinsing solution. Preferred solvents include C3-C10 alcohols, C8-C12 ether compounds, C6-C12 alkanes, alkenes, alkynes, and aromatic solvents.

[0274] The C3-C10 alcohols include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, Examples include 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol.

[0275] Examples of the ether compounds having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, and di-n-hexyl ether.

[0276] Examples of C6-C12 alkanes include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Examples of C6-C12 alkenes include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of C6-C12 alkynes include hexine, heptine, and octin.

[0277] Examples of the aforementioned aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0278] Rinsing can reduce the occurrence of deformation and defects in the resist pattern. However, rinsing is not always necessary, and omitting it can reduce the amount of solvent used.

[0279] The developed hole patterns and trench patterns can also be shrunk using thermal flow, RELACS, or DSA techniques. A shrinking agent is applied to the hole pattern, and crosslinking of the shrinking agent occurs on the surface of the resist film due to the diffusion of an acid catalyst from the resist film during baking, causing the shrinking agent to adhere to the side walls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, during which excess shrinking agent is removed and the hole pattern is reduced in size. [Examples]

[0280] 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 apparatus used is as follows. • MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0281] [1] Synthesis of onium salt type monomers [Example 1-1] Synthesis of onium salt type monomer a-1 [ka]

[0282] (1) Synthesis of intermediate In-1 Under a nitrogen atmosphere, raw materials SM-1 (7.9g), SM-2 (15.9g), 4-dimethylaminopyridine (0.5g), and methylene chloride (70g) were added to a reaction vessel and cooled in an ice bath. While maintaining the temperature inside the reaction vessel below 20°C, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (9.2g) was added in powder form. After addition, the temperature was raised to room temperature and aged for 12 hours. After aging, water (50g) was added to stop the reaction, and a normal aqueous work-up was performed. After removing the solvent by distillation, diisopropyl ether was added and recrystallization was performed to obtain 19.3g of intermediate In-1 as white crystals (yield 86%).

[0283] (2) Onium salt type monomer a -1 synthesis Under a nitrogen atmosphere, intermediate In-1 (19.3g), starting material SM-3 (11.9g), methyl isobutyl ketone (100g), and water (70g) were added to a reaction vessel. After stirring for 30 minutes, the organic layer was separated, washed with water, and then concentrated under reduced pressure to obtain 22.0g of the target monomer a-1 as an oily substance (yield 93%).

[0284] MALDI TOF-MS: POSITIVE M + 277(C 18 H 13 OS + equivalent) NEGATIVE M - 407(C 16 H8F5O5S - equivalent)

[0285] [Examples 1-2 to 1-7] Synthesis of onium salt type monomers a-2 to a-7 Using corresponding raw materials and known organic synthesis reactions, onium salt type monomers a-2 to a-7, represented by the following formulas, were synthesized. [ka]

[0286] [Comparative Examples 1-1 to 1-4] Synthesis of Comparative Monomers Ca-1 to Ca-4 Using corresponding raw materials and known organic synthesis reactions, comparative monomers ca-1 to ca-4, represented by the following formulas, were synthesized. [ka]

[0287] [2] Synthesis of base polymers Of the monomers used in the synthesis of the base polymer, a -1~ a - 7th grade Other comparative monomers besides CA-1 to CA-4 are as follows: [ka]

[0288] [ka]

[0289] [ka]

[0290] [Example 2-1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, monomer a-1 (15.7g), monomer b1-1 (18.8g), monomer c-1 (5.5g), 1.76g of V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 50g of MEK were placed in a flask to prepare a monomer-polymerization initiator solution. In another flask under a nitrogen atmosphere, 19g of MEK was placed and heated to 80°C with stirring, and then the monomer-polymerization initiator solution was added dropwise over 4 hours. After the addition was complete, stirring was continued for 2 hours while maintaining the temperature of the polymerization solution at 80°C, and then it was cooled to room temperature. The obtained polymerization solution was added dropwise to 800g of hexane that had been vigorously stirred, and the precipitated polymer was filtered off. Furthermore, the obtained polymer was washed twice with 240g of hexane, and then vacuum dried at 50°C for 20 hours to obtain a white powdery polymer P-1 (yield 39.2g, yield 98%). The Mw of polymer P-1 was 9700, and the Mw / Mn ratio was 1.82. Note that Mw is a polystyrene-converted value measured using GPC with DMF as the solvent. [ka]

[0291] [Examples 2-2 to 2-20, Comparative Examples 2-1 to 2-10] Synthesis of polymers P-2 to P-20 and comparative polymers CP-1 to CP-10 Except for changing the types and proportions of each monomer, implementation The polymers shown in Tables 1 and 2 were produced using the same method as in Example 2-1.

[0292] [Table 1]

[0293] [Table 2]

[0294] [3] Preparation of resist composition [Examples 3-1 to 3-20, Comparative Examples 3-1 to 3-10] A solution was prepared by dissolving predetermined components selected from the base polymers (P-1 to P-20), comparative base polymers (CP-1 to CP-10), acid generators (PAG-1, PAG-2), and quenchers (SQ-1 to SQ-3, AQ-1) of the present invention in a solvent containing 0.01% by mass of FC-4430 manufactured by 3M as a surfactant, in the compositions shown in Tables 3 and 4 below. The solution was then filtered through a 0.2 μm Teflon® type filter to prepare chemically amplified resist compositions (R-1 to R-20, CR-1 to CR-10).

[0295] [Table 3]

[0296] [Table 4]

[0297] In Tables 3 and 4, the solvents, quenchers (SQ-1 to SQ-3, AQ-1), and acid generators (PAG-1, PAG-2) are as follows: • Solvent: PGMEA (Propylene glycol monomethyl ether acetate) DAA (Diacetone Alcohol)

[0298] • Quencher: SQ-1~SQ-3, AQ-1 [ka]

[0299] • Acid generators: PAG-1, PAG-2 [ka]

[0300] [4] EUV lithography evaluation (1) [Examples 4-1 to 4-20, Comparative Examples 4-1 to 4-10] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-10) shown in Tables 3 and 4 was spin-coated onto a Si substrate formed with a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. to a thickness of 20 nm. The resist film was then pre-baked at 100°C for 60 seconds using a hot plate to produce a 50 nm thick resist film. This film was then exposed to an LS pattern with a wafer dimension of 18 nm and a pitch of 36 nm using an ASML EUV scanner NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination) by varying the exposure dose and focus (exposure dose pitch: 1 mJ / cm²). 2 The process was carried out while adjusting the focus pitch (0.020 μm), and after exposure, PEB was performed for 60 seconds at the temperatures shown in Tables 5 and 6. Then, paddle development was performed for 30 seconds with a 2.38 mass% TMAH aqueous solution, rinsed with a surfactant-containing rinse material, and spin-dried to obtain a positive type pattern. The obtained LS patterns were observed using a Hitachi High-Technologies Corporation measuring SEM (CG6300), and the sensitivity, EL, LWR, DOF, and tilt limit were evaluated according to the method described below. The results are shown in Tables 5 and 6.

[0301] [Sensitivity evaluation] Optimal exposure amount E for obtaining an LS pattern with a line width of 18 nm and a pitch of 36 nm op (mJ / cm 2 The value of ) was calculated and defined as the sensitivity. The smaller this value, the higher the sensitivity.

[0302] [EL rating] The exposure amount formed within ±10% (16.2 to 19.8 nm) of the 18 nm space width in the aforementioned LS pattern was used to calculate the EL (in %) using the following formula. A larger value indicates better performance. EL(%)=(|E1-E2| / E op ) × 100 E1: Optimal exposure amount to give an LS pattern with a line width of 16.2 nm and a pitch of 36 nm. E2: Optimal exposure amount to give an LS pattern with a line width of 19.8 nm and a pitch of 36 nm. E op: Optimal exposure amount to give an LS pattern with a line width of 18nm and a pitch of 36nm

[0303] [LWR rating] E op The LS pattern obtained by irradiation was measured at 10 points along the longitudinal direction of the line, and the LWR was calculated as three times the standard deviation (σ) (3σ) from the results. The smaller this value, the less roughness and the more uniform the line width pattern obtained.

[0304] [DOF rating] To evaluate the depth of focus, the focus range formed within ±10% of the 18nm dimension (16.2 to 19.8nm) in the aforementioned LS pattern was determined. A larger value indicates a wider depth of focus.

[0305] [Evaluation of the limit of line pattern collapse] The line dimensions for each exposure amount at the optimal focus of the aforementioned LS pattern were measured at 10 points along the longitudinal direction. The thinnest line dimension obtained without collapse was defined as the collapse limit dimension. The smaller this value, the better the collapse limit.

[0306] [Table 5]

[0307] [Table 6]

[0308] The results shown in Tables 5 and 6 indicate that the chemically amplified resist composition using a base polymer containing the onium salt monomer of the present invention exhibits excellent EL, LWR, and DOF with good sensitivity. Furthermore, it was confirmed that the tilt limit value is small and that the pattern is resistant to tilting even in the formation of fine patterns. Therefore, the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[0309] [5] EUV Lithography Evaluation (2) [Examples 5-1 to 5-20, Comparative Examples 5-1 to 5-10] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-10) shown in Tables 3 and 4 was spin-coated onto 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. had been formed to a thickness of 20 nm. The resist film was then pre-baked at 105°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. This was then exposed using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, wafer-mounted dimensions of 46 nm pitch, +20% bias hole pattern mask), and PEB was performed for 60 seconds at the temperatures listed in Tables 7 and 8 using a hot plate. Development was then performed with a 2.38% by mass TMAH aqueous solution for 30 seconds to form a hole pattern with dimensions of 23 nm. Using a Hitachi High-Technologies Corporation length-measuring SEM (CG6300), the exposure amount when a hole dimension of 23 nm was formed was measured and defined as the sensitivity. The dimensions of 50 holes at that time were also measured, and the dimensional variation (CDU) was defined as three times the standard deviation (σ) calculated from the results (3σ). The results are shown in Tables 7 and 8.

[0310] [Table 7]

[0311] [Table 8]

[0312] The results shown in Tables 7 and 8 confirm that the chemically amplified resist composition of the present invention exhibits good sensitivity and excellent CDU.

[0313] [6] Dry etching resistance evaluation [Examples 6-1 to 6-20, Comparative Examples 6-1 to 6-10] Two g each of the polymers shown in Tables 1 and 2 (polymers P-1 to P-20, comparative polymers CP-1 to CP-10) was dissolved in 10 g of cyclohexanone, filtered through a 0.2 μm size filter, and the resulting polymer solution was spin-coated onto a Si substrate to a thickness of 300 nm. The films were then evaluated under the following conditions. Etching test with CHF3 / CF4 gas: The difference in polymer film thickness before and after etching was determined using the TE-8500P dry etching system manufactured by Tokyo Electron Ltd. The etching conditions are as follows: Chamber pressure 40 Pa RF Power 1000W Gap 9mm CHF3 gas flow rate: 30 mL / min CF4 gas flow rate: 30 mL / min Ar gas flow rate: 100 mL / min Time 60sec This evaluation indicates that materials with less film thickness variation, i.e., those with less reduction in film thickness, have higher etching resistance. The results of the dry etching resistance are shown in Tables 9 and 10.

[0314] [Table 9]

[0315] [Table 10]

[0316] The results shown in Tables 9 and 10 confirm that the polymer of the present invention has excellent dry etching resistance to CHF3 / CF4 gases.

Claims

1. An onium salt type monomer represented by the following formula (a1). 【Chemistry 1】 (In the formula, n1 is an integer between 0 and 4. n2 is an integer between 0 and 4.) R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 1 This is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a halogen atom or a heteroatom. When n1 ≥ 2, multiple R 1 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. L A and L B These are, independently, a single bond, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a carbonate bond, or a carbamate bond. X L This group is a single bond or a group represented by any of the following formulas X L-0 to X L-49. 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 (In the formula, * represents a bond between L A and L B.) Q 1 and Q 2 These are, independently, a hydrogen atom, a fluorine atom, a C1-C6 hydrocarbyl group, or a C1-C6 fluorinated saturated hydrocarbyl group. Q 3 and Q 4 are each independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Z + This is an onium cation.

2. The onium salt type monomer according to Claim 1, wherein n1 is 0 or 1.

3. The onium salt type monomer according to claim 1, which is represented by the following formula (a1-1). 【Transformation 5】 (In the formula, n1, n2, R A , R 1 , L A , L B , X L Q 1 Q 2 and Z + (This is the same as above.)

4. The onium salt type monomer according to claim 3, which is represented by the following formula (a1-2). 【Transformation 6】 (In the formula, n1, n2, R A , R 1 , L A , X L Q 1 Q 2 and Z + (This is the same as above.)

5. Z + The onium salt type monomer according to claim 1, wherein the sulfonium cation is represented by the following formula (caten-1) or the iodonium cation is represented by the following formula (caten-2). 【Transformation 7】 (In the formula, R ct1 ~R ct5 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom.

6. A polymer comprising repeating units derived from the onium salt type monomer described in claim 1.

7. Furthermore, the polymer according to claim 6, comprising a repeating unit represented by the following formula (b1) or (b2). 【Transformation 8】 (In the formula, R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 This consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-O-X 11 - or * - C (= O) - NH - X 11 - and the phenylene group or naphthylene group may be substituted with a carbon-1 to carbon-10 alkoxy group or halogen atom which may contain a fluorine atom. 11 This is a saturated hydrocarbylene group, a phenylene group, or a naphthylene group having 1 to 10 carbon atoms, and the saturated hydrocarbylene group may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. X 2 These are single bonds, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond with a carbon atom in the main chain. AL 1 and AL 2 These are, independently, acid-unstable groups. R 11 This is a C1-C20 hydrocarbyl group which may contain a halogen atom, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyl group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. (a is an integer between 0 and 4.)

8. Furthermore, the polymer according to claim 6, comprising a repeating unit represented by the following formula (c1). 【Chemistry 9】 (In the formula, R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y 1 The bonds are single bonds, *-C(=O)-O-, or *-C(=O)-NH-. The asterisk (*) represents a bond with a carbon atom in the main chain. R 21 This is a C1-C20 hydrocarbyl group which may contain a halogen atom, a nitro group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyl group which may contain a heteroatom, a C2-C20 hydrocarbylcarbonyloxy group which may contain a heteroatom, or a C2-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. c is an integer between 1 and 4. d is an integer between 0 and 3. However, 1 ≤ c + d ≤ 5.

9. Furthermore, the polymer according to claim 6, comprising a repeating unit represented by the following formula (d1). 【Chemistry 10】 (In the formula, R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z 1 This consists of a single bond, a phenylene group, a naphthylene group, and *-C(=O)-O-Z. 11 - or * - C (= O) - NH - Z 11 - or the phenylene group or naphthylene group may be substituted with a carbon-1 to carbon-10 alkoxy group or halogen atom which may contain a fluorine atom. * represents a bond with a carbon atom of the main chain. Z 11 This is a saturated hydrocarbylene group, a phenylene group, or a naphthylene group having 1 to 10 carbon atoms, and the saturated hydrocarbylene group may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. R 31 This is a group having 1 to 20 carbon atoms that includes at least one structure selected from a hydrogen atom, or a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl 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)-).

10. (A) A chemically amplified resist composition comprising a base polymer containing the polymer described in any one of claims 6 to 9.

11. Furthermore, the chemically amplified resist composition according to claim 10, further comprising (B) an organic solvent.

12. Furthermore, the chemically amplified resist composition according to claim 10, further comprising (C) a quencher.

13. Furthermore, the chemically amplified resist composition according to claim 10, further comprising (D) an acid generator.

14. Furthermore, the chemically amplified resist composition according to claim 10, further comprising (E) a surfactant.

15. A pattern forming method comprising the steps of: forming a resist film on a substrate using the chemically amplified resist composition according to claim 10; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer.

16. The pattern formation method according to claim 15, wherein the high-energy beam is ArF excimer laser light with a wavelength of 193 nm or KrF excimer laser light with a wavelength of 248 nm, an electron beam or extreme ultraviolet light with a wavelength of 3 to 15 nm.

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