Onium salt, chemically amplified resist composition and pattern forming method

Abstract

The invention relates to an onium salt, a chemically amplified resist composition and a pattern forming method. The present invention addresses the problem of providing: a chemically amplified resist composition which has excellent LWR and resolution and is capable of suppressing collapse of a resist pattern in optical lithography using high-energy rays, such as extreme ultraviolet lithography, EUV lithography, and electron beam (EB) lithography; an onium salt used therein; and a pattern forming method using the chemically amplified resist composition. [Solution] An onium salt represented by formula (1). # imgabs0 #

Description

Technical Field

[0001] The invention relates to an onium salt, a chemically amplified resist composition and a pattern forming method. Background Art

[0002] With the high integration and high speed of LSI, the miniaturization of pattern rules is progressing rapidly. This is because the high-speed communication of 5G and the popularization of artificial intelligence (AI) have made it necessary to have high-performance devices to handle them. As for the most advanced miniaturization technology, some people have carried out mass production of 5nm node devices using extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm. In addition, some people are also conducting research on the use of EUV lithography in the next generation 3nm node and the next generation 2nm node devices.

[0003] As the miniaturization progresses, the blurring of images due to the diffusion of acid becomes a problem. In order to ensure the resolution of fine patterns with a size of 45 nm or more, it has been proposed that in addition to the improvement of the dissolution contrast proposed previously, the control of acid diffusion is also important (Non-Patent Document 1). However, chemically amplified resist compositions improve sensitivity and contrast through the diffusion of acid, so if the post-exposure baking (PEB) temperature is reduced and the time is shortened to suppress the diffusion of acid to the limit, the sensitivity and contrast will be significantly reduced.

[0004] There is a triangular trade-off relationship between sensitivity, resolution, and edge roughness (LER, LWR). In order to improve the resolution, acid diffusion must be suppressed, but if the acid diffusion distance is shortened, the sensitivity will decrease.

[0005] It is effective to add an acid generator that generates a bulky acid to inhibit acid diffusion. In this regard, it has been proposed that a repeating unit from an onium salt having a polymerizable unsaturated bond is contained in the polymer. In this case, the polymer functions as an acid generator (polymer-bonded acid generator). In Patent Document 1, it has been proposed that a sulfonium salt or an iodonium salt having a polymerizable unsaturated bond that generates a specific sulfonic acid be used. In Patent Document 2, it has been proposed that a sulfonium salt in which a sulfonic acid is directly bonded to the main chain be used.

[0006] In order to efficiently carry out the deprotection reaction of the acid-labile group of the base polymer, a photoacid generator that generates α,α-fluoroalkanesulfonic acid is used, especially in ArF resist compositions and EUV resist compositions. Patent document 3 describes a photoacid generator that generates 2-acyloxy-1,1,3,3,3-pentafluoropropane-1-sulfonic acid, which has excellent solubility and stability in solvents and can have a wide range of molecular designs. In particular, a photoacid generator that generates 2-(1-adamantyloxy)-1,1,3,3,3-pentafluoropropane-1-sulfonic acid into which a highly bulky substituent is introduced has small acid diffusion. In addition, patent documents 4 to 6 also describe photoacid generators that generate α,α-fluoroalkanesulfonic acids of various structures. Since they have fluorine atoms on the carbon atoms adjacent to the sulfonic acid group, they generate strong acids.

[0007] Patent Documents 7 and 8 describe photoacid generators having a trifluoromethyl group at the β-position of the sulfonic acid group. Although these do not have the acidity of the aforementioned α,α-fluoroalkanesulfonic acid, they have a moderate acidity and allow the deprotection reaction to proceed according to the reactivity of the acid-labile group of the base polymer.

[0008] Then, it was proposed to introduce an onium salt containing a nitrogen functional group into the anion part of the photoacid generator that generates fluoroalkanesulfonic acid. Patent document 9 describes a photoacid generator that generates α,α-fluoroalkanesulfonic acid having aniline as an aromatic amine and pyridine as a nitrogen-containing aromatic ring in the anion part. In addition, Patent document 10 describes a photoacid generator that generates α,α-fluoroalkanesulfonic acid having a structure in which aliphatic amine is protected with an acid-labile group in the anion part. These nitrogen-containing functional groups have the function of capturing acid in the exposed part of the resist pattern and have the effect of reducing excessive acid diffusion. By using them, the triangular trade-off relationship between sensitivity, resolution and edge roughness will be improved to some extent, but satisfactory results have not been obtained so far. In order to respond to the demand for further miniaturization, the development of photoacid generators with low acid diffusion is important, and the development of materials that overcome these problems is expected.

[0009] Prior art literature

[0010] Patent Literature

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 11-125907

[0012] [Patent Document 2] Japanese Patent Application Laid-Open No. 11-327143

[0013] [Patent Document 3] Japanese Patent Application Publication No. 2007-145797

[0014] [Patent Document 4] Japanese Patent Application Publication No. 2021-11478

[0015] [Patent Document 5] Japanese Patent Application Publication No. 2019-112435

[0016] [Patent Document 6] Japanese Patent No. 6769783

[0017] [Patent Document 7] Japanese Patent No. 5815575

[0018] [Patent Document 8] International Publication No. 2022 / 244682

[0019] [Patent Document 9] Japanese Patent No. 6013218

[0020] [Patent Document 10] Japanese Patent No. 5821543 Summary of the invention

[0021] [Problems to be solved by the invention]

[0022] The present invention is made in view of the above-mentioned situation, and its purpose is to provide: a chemically amplified resist composition that has excellent LWR and resolution and can suppress the collapse of the resist pattern in optical lithography using high-energy rays such as extreme ultraviolet lithography, EUV lithography and electron beam (EB) lithography; an onium salt used therein; and a pattern forming method using the chemically amplified resist composition.

[0023] [Methods to solve the problem]

[0024] The inventors of the present application have conducted intensive studies to achieve the above-mentioned purpose, and as a result, have found that an onium salt containing an aliphatic heterocycle containing a nitrogen atom and an anion having a fluorine atom or a fluorinated hydrocarbon group at the β-position of the sulfonic acid group is a photoacid generator and a quencher, that is, has both the functions of a photoacid generator and a quencher. Furthermore, a chemically amplified resist composition containing the above-mentioned onium salt has excellent resolution of the resist film, a small LWR, and suppresses swelling during development, and is extremely effective in precise microfabrication, thereby completing the present invention.

[0025] That is, the present invention provides the following onium salt, chemically amplified resist composition and pattern forming method.

[0026] 1. An onium salt represented by the following formula (1);

[0027] [Chemistry 1]

[0028]

[0029] Wherein, n1 is an integer from 0 to 6; n2 is 1 or 2;

[0030] W is an aliphatic heterocyclic ring having 2 to 20 carbon atoms and containing a nitrogen atom which may also contain a heteroatom;

[0031] LA and L B each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond or a carbamate bond;

[0032] X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom;

[0033] R 1 is a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms; when n1≥2, multiple R 1 They may also be bonded to each other and to form a ring together with the carbon atom on W to which they are bonded;

[0034] R 2 and R 3 are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; and R 2 and R 3 They may also bond to each other and form a ring together with the carbon atoms to which they are bonded;

[0035] Q 1 and Q 2 Each independently represents a hydrogen atom, a fluorine atom, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms; but Q 1 and Q 2 At least one of them is a fluorine atom or a fluorinated hydrocarbon group having 1 to 6 carbon atoms;

[0036] R AL It is an acid-labile group;

[0037] Z + It is an onium cation.

[0038] 2. The onium salt of 1, wherein R AL A group represented by the following formula (AL-1) or (AL-2);

[0039] [Chemistry 2]

[0040]

[0041] Where, L C is -O- or -S-;

[0042] R 4 , R 5 and R 6 are each independently a hydrocarbon group having 1 to 10 carbon atoms; and R 4 , R 5 and R 6 Any two of them may also be bonded to each other to form a ring together with the carbon atoms to which they are bonded;

[0043] R 7 and R8 Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; R 9 is a hydrocarbon group having 1 to 20 carbon atoms, wherein -CH2- in the hydrocarbon group may be substituted by -O- or -S-; and R 8 and R 9 They can also bond to each other and to the carbon atoms and L C Together they form a heterocyclic group having 3 to 20 carbon atoms, wherein -CH2- in the heterocyclic group may be substituted by -O- or -S-;

[0044] m1 and m2 are each independently 0 or 1;

[0045] * indicates an atomic bond to an adjacent -O- atom.

[0046] 3. The onium salt of 1 or 2, wherein Z + It is a sulfonium cation represented by the following formula (cation-1), an iodonium cation represented by the following formula (cation-2), or an ammonium cation represented by the following formula (cation-3);

[0047] [Chemistry 3]

[0048]

[0049] In the formula, R c 1 ~R c9 are each independently a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom; and R c 1 and R c2 They may also bond to each other to form a ring together with the sulfur atom to which they are bonded.

[0050] 4. The onium salt according to any one of 1 to 3, represented by the following formula (1A);

[0051] [Chemistry 4]

[0052]

[0053] Where n1, n2, W, L A , X L , R 1 ~R 3 , Q 1 , Q 2 , R AL and Z + Same as above.

[0054] 5. The onium salt of 4 is represented by the following formula (1B);

[0055] [Chemistry 5]

[0056]

[0057] Where n1, W, L A , X L , R 1 ~R 3 , R AL and Z + Same as above.

[0058] 6. A photoacid generator and quencher, which is composed of the onium salt according to any one of 1 to 5.

[0059] 7. A chemically amplified resist composition comprising the photoacid generator and quencher of 6.

[0060] 8. The chemically amplified resist composition of 7 further comprises an organic solvent.

[0061] 9. The chemically amplified resist composition of 7 or 8, comprising a base polymer containing a repeating unit represented by the following formula (a1);

[0062] [Chemistry 6]

[0063]

[0064] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0065] X 1 is a single bond, phenylene, naphthylene or *-C(=O)-OX 11 -, the phenylene or naphthylene group may be substituted by an alkoxy group having 1 to 10 carbon atoms which may also contain a fluorine atom or a halogen atom; X 11 It is a saturated alkylene group, phenylene group or naphthylene group having 1 to 10 carbon atoms. The saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. * represents an atomic bond to a carbon atom of the main chain;

[0066] AL 1 It is an acid-labile group.

[0067] 10. The chemically amplified resist composition of 9, wherein the base polymer further comprises a repeating unit represented by the following formula (a2);

[0068] [Chemistry 7]

[0069]

[0070] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0071] X 2 is a single bond or *-C(=O)-O-; * represents an atomic bond to a carbon atom of the main chain;

[0072] R 11 is a halogen atom, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom;

[0073] AL 2 It is an acid-labile group;

[0074] a is an integer from 0 to 4.

[0075] 11. The chemically amplified resist composition of 9 or 10, wherein the base polymer further comprises a repeating unit represented by the following formula (b1) or (b2);

[0076] [Chemistry 8]

[0077]

[0078] In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0079] Y 1 is a single bond or *-C(=O)-O-; * represents an atomic bond to a carbon atom of the main chain;

[0080] R 21 A group having 1 to 20 carbon atoms and a structure containing at least one selected from the group consisting of 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 sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-);

[0081] R 22 is a halogen atom, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom;

[0082] b is an integer from 1 to 4; c is an integer from 0 to 4; but 1≤b+c≤5.

[0083] 12. The chemically amplified resist composition according to any one of items 9 to 11, wherein the base polymer further comprises a repeating unit represented by any one of the following formulae (c1) to (c4);

[0084] [Chemistry 9]

[0085]

[0086] In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;

[0087] Z 1 is a single bond or a phenylene group;

[0088] Z 2 **-C(=O)-OZ 21 -, **-C(=O)-NH-Z 21 -or**-OZ 21 -;Z 21 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group;

[0089] Z 3 Each is independently a single bond, phenylene, naphthylene or *-C(=O)-OZ 31 -;Z 31 is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring;

[0090] Z 4 Each is independently a single bond, ***-Z 41 -C(=O)-O-、***-C(=O)-NH-Z 41 -or***-OZ 41 -;Z 41 is an alkylene group having 1 to 20 carbon atoms which may contain heteroatoms;

[0091] Z 5 Each is independently a single bond, ****-Z 51 -C(=O)-O-、****-C(=O)-NH-Z 51 -or****-OZ 51 -;Z 51 is an alkylene group having 1 to 20 carbon atoms which may contain heteroatoms;

[0092] Z 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 61 -, *-C(=O)-N(H)-Z 61 -or*-OZ 61 -;Z 61 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group;

[0093] * indicates an atomic bond to a carbon atom in the main chain; ** indicates an atomic bond to Z 1 Atomic bonds with Z 3 Atomic bonds with Z 4 Atomic bonds;

[0094] R 31 and R 32 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; and R 31 and R 32 They may also bond to each other and form a ring together with the sulfur atom to which they are bonded;

[0095] L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond;

[0096] R 1 and Rf 2 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms;

[0097] R 3 and Rf 4 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms;

[0098] R 5 and Rf 6 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; however, all Rf 5 and Rf 6 Not all hydrogen atoms at the same time;

[0099] M - It is a non-nucleophilic counter ion;

[0100] A + is an onium cation;

[0101] d is an integer from 0 to 3.

[0102] 13. The chemically amplified resist composition according to any one of items 7 to 12, further comprising a photoacid generator.

[0103] 14. The chemically amplified resist composition according to any one of items 7 to 13, further comprising a quencher.

[0104] 15. The chemically amplified resist composition according to any one of items 7 to 14, further comprising a surfactant.

[0105] 16. A method for forming a pattern, comprising the following steps:

[0106] A resist film is formed on a substrate using the chemically amplified resist composition of any one of items 7 to 15; the resist film is exposed to high-energy rays; and the exposed resist film is developed using a developer.

[0107] 17. The pattern forming method of 16, wherein the high-energy ray is KrF excimer laser, ArF excimer laser, EB or EUV with a wavelength of 3 to 15 nm.

[0108] [Effects of the Invention]

[0109] The onium salt of the present invention can well function as a photoacid generator and quencher in a chemically amplified resist composition. The resist film obtained from the chemically amplified resist composition containing the onium salt of the present invention has good sensitivity and excellent dissolution contrast. As a result, the size uniformity (CDU) of the hole pattern and the LWR of the line pattern are improved, and a high-resolution pattern profile with excellent rectangularity can be constructed. BRIEF DESCRIPTION OF THE DRAWINGS

[0110] [ Figure 1 ] is the onium salt NPAG-1 obtained in Example 1-1 1 H-NMR spectrum.

[0111] [ Figure 2 ] is the onium salt NPAG-2 obtained in Example 1-2 1 H-NMR spectrum. DETAILED DESCRIPTION

[0112] [Onium salt]

[0113] The onium salt of the present invention is represented by the following formula (1).

[0114] [Chemistry 10]

[0115]

[0116] In formula (1), n1 is an integer of 0 to 6. n2 is 1 or 2, preferably 1.

[0117] In formula (1), W is an aliphatic heterocyclic ring having 2 to 20 carbon atoms and containing a nitrogen atom which may contain a heteroatom. Specific examples of the structure of W include those shown below, but are not limited to these. In the following formula, * represents the same as L. A The atomic bond between R AL Atomic bond of -OC(=O)-.

[0118] [Chemistry 11]

[0119]

[0120] In formula (1), L A and L B Each independently represents a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond or a urethane bond. Among these, a single bond, an ether bond, an ester bond or an amide bond is more preferred, and a single bond, an ester bond or an amide bond is more preferred.

[0121] In formula (1), X L is a single bond or a alkylene group having 1 to 40 carbon atoms which may contain a hetero atom. The alkylene group may be linear, branched or cyclic, and specific examples thereof include alkanediyl and cyclic saturated alkylene groups. Specific examples of the hetero atom include oxygen atoms, nitrogen atoms, sulfur atoms, etc.

[0122] Just X L Specific examples of the alkylene group having 1 to 40 carbon atoms which may contain a hetero atom as represented by the formula include those shown below, but are not limited to these. A and L B of atomic bonds.

[0123] [Chemistry 12]

[0124]

[0125] [Chemistry 13]

[0126]

[0127] [Chemistry 14]

[0128]

[0129] [Chemistry 15]

[0130]

[0131] Among these, X L -0~X L -22 and X L -47~X L -58 is ideal.

[0132] In formula (1), R 1is a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be any of linear, branched, and cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, 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, tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as decyl, adamantyl, and adamantylmethyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and anthracenyl; groups obtained by combining them, etc. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of -CH2- of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, carbamate bonds, amide bonds, imide bonds, lactone rings, sultone rings, thiolactone rings, lactam rings, sultams, carboxylic anhydrides (-C(=O)-OC(=O)-), and haloalkyl groups may be contained.

[0133] Again, when n1≥2, multiple R 1 They may also be bonded to each other and form a ring together with the carbon atom on W to which they are bonded. Specific examples of the ring formed at this time include cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, norbornane ring, adamantane ring, etc. In addition, part or all of the hydrogen atoms in the aforementioned ring may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and part of -CH2- in the aforementioned ring may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, it may also contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. In addition, two R bonded to the same atom forming W 1 They may be bonded to each other to form a ring or a spiro ring.

[0134] In formula (1), R 2 and R 3 Each is independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be straight chain, branched, or cyclic. Specific examples thereof include: 1 The hydrocarbon groups exemplified are the same as those exemplified above.

[0135] Again, R 2 and R 3 They may also be bonded to each other to form a ring together with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include: 1 The examples of the rings that can be formed by mutually bonding are the same as those given above.

[0136] In formula (1), Q 1 and Q 2 Each independently represents a hydrogen atom, a fluorine atom, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms. 1 and Q 2 At least one of Q is a fluorine atom or a fluorinated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated hydrocarbon group having 1 to 6 carbon atoms is preferably a trifluoromethyl group. 1 and Q 2 All of them are preferably trifluoromethyl.

[0137] In formula (1), R AL is an acid-labile group. Specifically, R AL Preferably, the group is represented by the following formula (AL-1) or (AL-2).

[0138] [Chemistry 16]

[0139]

[0140] In the formula, * represents an atomic bond to the adjacent -O-.

[0141] In formula (AL-2), L C It is -O- or -S-.

[0142] In formula (AL-1), R 4 , R 5 and R 6 are each independently a hydrocarbon group having 1 to 10 carbon atoms. 4 , R 5 and R 6 Any two of them may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. m1 is 0 or 1.

[0143] In formula (AL-2), R 7 and R 8 Each R is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. 9 is a hydrocarbon group having 1 to 20 carbon atoms, wherein the -CH2- of the hydrocarbon group may be substituted by -O- or -S-. 8 and R 9 They can also bond to each other and to the carbon atoms and L CTogether they form a heterocyclic group having 3 to 20 carbon atoms, wherein -CH2- in the heterocyclic group may be substituted by -O- or -S-. m2 is 0 or 1.

[0144] Specific examples of the acid-labile group represented by formula (AL-1) include those shown below, but are not limited to these. In the following formula, * represents an atomic bond with an adjacent -O-.

[0145] [Chemistry 17]

[0146]

[0147] [Chemistry 18]

[0148]

[0149] [Chemistry 19]

[0150]

[0151] [Chemistry 20]

[0152]

[0153] [Chemistry 21]

[0154]

[0155] [Chemistry 22]

[0156]

[0157] [Chemistry 23]

[0158]

[0159] [Chemistry 24]

[0160]

[0161] [Chemistry 25]

[0162]

[0163] [Chemistry 26]

[0164]

[0165] [Chemistry 27]

[0166]

[0167] Specific examples of the acid-labile group represented by the formula (AL-2) include those shown below, but are not limited to these. In the following formula, * represents an atomic bond with an adjacent -O-.

[0168] [Chemistry 28]

[0169]

[0170] [Chemistry 29]

[0171]

[0172] The onium salt represented by the formula (1) is preferably represented by the following formula (1A).

[0173] [Chemistry 30]

[0174]

[0175] Where n1, n2, W, L A , X L , R 1 ~R 3 , Q 1 , Q 2 , R AL and Z + Same as above.

[0176] The onium salt represented by the formula (1A) is preferably represented by the following formula (1B).

[0177] [Chemistry 31]

[0178]

[0179] Where n1, W, L A , X L , R 1 ~R 3 , R AL and Z + Same as above.

[0180] Specific examples of the anion of the onium salt represented by the formula (1) include those shown below, but are not limited to these.

[0181] [Chemistry 32]

[0182]

[0183] [Chemistry 33]

[0184]

[0185] [Chemistry 34]

[0186]

[0187] [Chemistry 35]

[0188]

[0189] [Chemistry 36]

[0190]

[0191] [Chemistry 37]

[0192]

[0193] [Chemistry 38]

[0194]

[0195] [Chemistry 39]

[0196]

[0197] [Chemistry 40]

[0198]

[0199] [Chemistry 41]

[0200]

[0201] [Chemistry 42]

[0202]

[0203] [Chemistry 43]

[0204]

[0205] [Chemistry 44]

[0206]

[0207] [Chemistry 45]

[0208]

[0209] [Chemistry 46]

[0210]

[0211] [Chemistry 47]

[0212]

[0213] [Chemistry 48]

[0214]

[0215] [Chemistry 49]

[0216]

[0217] [Chemistry 50]

[0218]

[0219] [Chemistry 51]

[0220]

[0221] [Chemistry 52]

[0222]

[0223] [Chemistry 53]

[0224]

[0225] [Chemistry 54]

[0226]

[0227] [Chemistry 55]

[0228]

[0229] [Chemistry 56]

[0230]

[0231] [Chemistry 57]

[0232]

[0233] [Chemistry 58]

[0234]

[0235] [Chemistry 59]

[0236]

[0237] [Chemistry 60]

[0238]

[0239] [Chemistry 61]

[0240]

[0241] [Chemistry 62]

[0242]

[0243] [Chemistry 63]

[0244]

[0245] [Chemistry 64]

[0246]

[0247] [Chemistry 65]

[0248]

[0249] [Chemistry 66]

[0250]

[0251] [Chemistry 67]

[0252]

[0253] [Chemistry 68]

[0254]

[0255] [Chemistry 69]

[0256]

[0257] [Chemistry 70]

[0258]

[0259] [Chemistry 71

[0260]

[0261] [Chemistry 72]

[0262]

[0263] [Chemistry 73]

[0264]

[0265] [Chemistry 74]

[0266]

[0267] [Chemistry 75]

[0268]

[0269] [Chemistry 76]

[0270]

[0271] [Chemistry 77]

[0272]

[0273] [Chemistry 78]

[0274]

[0275] [Chemistry 79]

[0276]

[0277] [Chemistry 80]

[0278]

[0279] [Chemistry 81]

[0280]

[0281] [Chemistry 82]

[0282]

[0283] [Chemistry 83]

[0284]

[0285] [Chemistry 84]

[0286]

[0287] [Chemistry 85]

[0288]

[0289] In formula (1), Z + The onium cation is preferably a sulfonium cation represented by the following formula (cation-1), an iodonium cation represented by the following formula (cation-2), or an ammonium cation represented by the following formula (cation-3).

[0290] [Chemistry 86]

[0291]

[0292] In formula (cation-1) to (cation-3), R c1～ R c9Each is independently a hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be any of linear, branched, and cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 30 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 30 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them, and aryl groups are more preferred. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. 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 sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0293] Again, R c1 and R c2 They may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, specific examples of the sulfonium cation represented by formula (cation-1) include those represented by the following formula.

[0294] [Chemistry 87]

[0295]

[0296] In the formula, the dotted line is the c3 of atomic bonds.

[0297] Specific examples of the cation of the sulfonium salt represented by the formula (cation-1) include those shown below, but are not limited to these.

[0298] [Chemistry 88]

[0299]

[0300] [Chemistry 89]

[0301]

[0302] [Chemistry 90]

[0303]

[0304] [Chemistry 91]

[0305]

[0306] [Chemistry 92]

[0307]

[0308] [Chemistry 93]

[0309]

[0310] [Chemistry 94]

[0311]

[0312] [Chemistry 95]

[0313]

[0314] [Chemistry 96]

[0315]

[0316] [Chemistry 97]

[0317]

[0318] [Chemistry 98]

[0319]

[0320] [Chemistry 99]

[0321]

[0322] [Chemical 100]

[0323]

[0324] [Chemistry 101]

[0325]

[0326] [Chemistry 102]

[0327]

[0328] [Chemistry 103]

[0329]

[0330] [Chemistry 104]

[0331]

[0332] [Chemistry 105]

[0333]

[0334] [Chemistry 106]

[0335]

[0336] [Chemistry 107]

[0337]

[0338] [Chemistry 108]

[0339]

[0340] [Chemistry 109]

[0341]

[0342] [Chemistry 110]

[0343]

[0344] [Chemistry 111]

[0345]

[0346] [Chemistry 112]

[0347]

[0348] [Chemistry 113]

[0349]

[0350] Specific examples of the iodonium cation represented by the formula (cation-2) include those shown below, but are not limited to these.

[0351] [Chemistry 114]

[0352]

[0353] [Chemistry 115]

[0354]

[0355] Specific examples of the ammonium cation represented by the formula (cation-3) include those shown below, but are not limited to these.

[0356] [Chemistry 116]

[0357]

[0358] Specific examples of the onium salt of the present invention include any combination of the above-mentioned anions and cations.

[0359] The onium salt of the present invention can be synthesized by a known method. As an example, a method for producing an onium salt represented by the following formula (NPAG-1-ex) will be described.

[0360] [Chemistry 117]

[0361]

[0362] Where n1, n2, W, L A , X L , R 1 ~R 3 , Q 1 , Q 2 , R ALU and Z + Same as above. + is a relative cation. - is the relative anion.

[0363] The first step is a step of obtaining the intermediate In-1-ex by reacting a raw material SM-1 which is commercially available or can be synthesized by a known synthesis method with a raw material SM-2. When a direct ester bond is formed by the carboxyl group of the raw material SM-1 and the hydroxyl group of the raw material SM-2, various condensing agents can be used. As for the condensing agent used, N, N'-dicyclohexylcarbodiimide, N, N'-diisopropylcarbodiimide, 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide, hydrochloric acid 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, etc. can be cited, but considering the ease of removing the urea compound generated as a by-product after the reaction, it is more ideal to use hydrochloric acid 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. The reaction is carried out by dissolving the raw materials SM-1 and SM-2 in a halogen-based solvent such as dichloromethane and adding a condensing agent. If 4-dimethylaminopyridine is added as a catalyst, the reaction rate can be improved. The reaction time, from the perspective of yield, is expected to be completed by tracking the reaction with silica gel thin layer chromatography (TLC), but it is usually about 12 to 24 hours. After the reaction is stopped, the by-produced urea compound is removed by filtration or water washing as needed, and the intermediate In-1-ex can be obtained by subjecting the reaction solution to a conventional aqueous work-up. The intermediate In-1-ex obtained can be refined by general methods such as distillation, chromatography, and recrystallization, if necessary.

[0364] The second step is to react the obtained intermediate In-1-ex with Z + X -The step of obtaining the onium salt NSQ-1-ex by salt exchange with the onium salt represented by X-. In addition, as for X-, chloride ion, bromide ion, iodide ion or methylsulfate anion is more desirable because the exchange reaction can be easily and quantitatively carried out. The progress of the reaction is expected to be confirmed by TLC from the perspective of yield. The onium salt NPAG-1-ex can be obtained from the reaction mixture by performing a conventional aqueous work-up. If necessary, it can be purified by general methods such as chromatography and recrystallization.

[0365] In the above embodiment, the ion exchange in the second step can be easily performed by a known method, and for example, Japanese Patent Application Laid-Open No. 2007-145797 can be referred to.

[0366] In addition, the above-mentioned production method is only an example, and the production method of the onium salt of the present invention is not limited thereto.

[0367] [Photoacid generator and quencher]

[0368] The onium salt of the present invention is useful as a photoacid generator and quencher. In the present invention, the photoacid generator refers to a compound that generates a strong acid due to high-energy ray irradiation, and the strong acid refers to a compound having sufficient acidity to initiate a deprotection reaction of an acid-labile group. The quencher refers to a material that captures the strong acid generated from the photoacid generator and prevents it from diffusing to the unexposed part, so as to form a desired pattern.

[0369] If the onium salt of the present invention is coexisted with an onium salt that generates a strong acid such as a fluorinated sulfonic acid, an imidic acid, or a methylated acid at the α position, the acid-labile group at the anion site of the onium salt of the present invention will be deprotected to generate an amine while the sulfonic acid having a fluorine atom or a fluorine-containing substituent at the β position and the strong acid are generated by light irradiation. The strong acid functions as a catalyst for initiating the deprotection reaction of the acid-labile group of the base polymer, and the sulfonic acid having a fluorine atom or a fluorine-containing substituent at the β position generated by the onium salt of the present invention also has a moderate acidity, so it has weak acidity and will cause the deprotection reaction to proceed according to the acid leaving reactivity of the acid-labile group. On the other hand, the amine generated at the anion site of the onium salt of the present invention functions as a quencher and has the function of capturing the generated acid. The strong acid and the weak acid diffuse the acid while performing countless proton exchanges while causing the leaving reaction of the base polymer to proceed, but the amine bonded intramolecularly of the weak acid functions as a quencher and inhibits excessive acid diffusion. Through these effects, an appropriate acid diffusion distance can be maintained, so the diffusion of acid to the unexposed part is suppressed, the contrast of the exposed part / unexposed part is improved, and the LWR of the line pattern and the CDU of the hole pattern can be improved.

[0370] [Chemically amplified resist composition]

[0371] The chemically amplified resist composition of the present invention contains (A) a photoacid generator / quencher composed of an onium salt represented by the formula (1) as an essential component.

[0372] In the chemically amplified resist composition of the present invention, the content of the photoacid generator and quencher (A) is preferably 0.1 to 40 parts by mass, and more preferably 1 to 20 parts by mass, relative to 80 parts by mass of the base polymer (C) described later. If the content of the photoacid generator and quencher (A) falls within the above range, it can fully function as a quencher, and there is no risk of performance degradation such as reduced sensitivity, insufficient solubility, and generation of foreign matter.

[0373] [(B) Organic solvent]

[0374] The chemically amplified resist composition of the present invention may also contain an organic solvent as the component (B). The organic solvent (B) is not particularly limited as long as it can dissolve the component (A) and the components described below. Specific examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ketoalcohols such as diacetone alcohol (DAA); ethers such as propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; lactones such as γ-butyrolactone (GBL), and mixed solvents thereof.

[0375] Among these organic solvents, PGME, PGMEA, cyclohexanone, GBL, DAA, ethyl lactate, and mixed solvents thereof are preferred because they have particularly excellent solubility in the base polymer of the component (C).

[0376] In the chemically amplified resist composition of the present invention, the content of the organic solvent (B) is preferably 200 to 5000 parts by mass, more preferably 400 to 3500 parts by mass, relative to 80 parts by mass of the base polymer (C) described later. The organic solvent (B) may be used alone or in combination of two or more.

[0377] [(C) Base polymer]

[0378] The chemically amplified resist composition of the present invention may contain a base polymer as the component (C). The base polymer (C) comprises a repeating unit represented by the following formula (a1) (hereinafter, also referred to as repeating unit a1).

[0379] [Chemistry 118]

[0380]

[0381] In formula (a1), X 1 is a single bond, phenylene, naphthylene or *-C(=O)-OX 11 -, the phenylene group or naphthylene group may be substituted with an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom or a halogen atom. 11 It is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group. The saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. * represents an atomic bond to a carbon atom of the main chain.

[0382] In formula (a1), AL 1 The acid-labile group includes those described in JP-A-2013-80033 and JP-A-2013-83821.

[0383] Representative examples of the acid-labile group include those represented by the following formulae (AL-3) to (AL-5).

[0384] [Chemistry 119]

[0385]

[0386] In the formula, the dotted lines are atomic bonds.

[0387] In formula (AL-3) and (AL-4), R L1 and R L2 Each is independently a saturated hydrocarbon group having 1 to 40 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The saturated hydrocarbon group may be straight-chain, branched, or cyclic. The saturated hydrocarbon group preferably has 1 to 20 carbon atoms.

[0388] In the formula (AL-3), k is an integer of 0-10, and preferably an integer of 1-5.

[0389] In formula (AL-4), R L3 and R L4 Each independently represents a hydrogen atom or a saturated hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The hydrocarbon group may be linear, branched, or cyclic. L2 , R L3 and R L4Any two of them may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. The above ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0390] In formula (AL-5), R L5 , R L6 and R L7 Each is independently a saturated hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The hydrocarbon group may be linear, branched, or cyclic. L5 , R L6 and R L7 Any two of them may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded. The above-mentioned ring is preferably a ring having 4 to 16 carbon atoms, and an alicyclic ring is particularly preferred.

[0391] Specific examples of the repeating unit a1 include those shown below, but are not limited to these. A and AL 1 Same as above.

[0392] [Chemistry 120]

[0393]

[0394] [Chemistry 121]

[0395]

[0396] [Chemistry 122]

[0397]

[0398] The aforementioned base polymer may further contain a repeating unit represented by the following formula (a2) (hereinafter, also referred to as repeating unit a2).

[0399] [Chemistry 123]

[0400]

[0401] In formula (a2), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 2 is a single bond or *-C(=O)-O-. * represents an atomic bond to a carbon atom of the main chain. 11It is a halogen atom, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom. 2 The acid-labile group is an acid-labile group. 1 The acid-labile groups represented by are the same as those exemplified above. a is an integer of 0 to 4, and is preferably 0 or 1.

[0402] Specific examples of the repeating unit a2 include those shown below, but are not limited to these. A and AL 2 Same as above.

[0403] [Chemistry 124]

[0404]

[0405] The base polymer preferably further includes 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).

[0406] [Chemistry 125]

[0407]

[0408] In formula (b1) and (b2), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 is a single bond or *-C(=O)-O-. * represents an atomic bond to a carbon atom of the main chain. 21 It is a hydrogen atom, or a group having 1 to 20 carbon atoms containing a structure including at least one selected from the group consisting of 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 sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-). 22 is a halogen atom, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom. b is an integer of 1 to 4. c is an integer of 0 to 4. However, 1≤b+c≤5.

[0409] Specific examples of the repeating unit b1 include those shown below, but are not limited to these. A Same as above.

[0410] [Chemistry 126]

[0411]

[0412] [Chemistry 127]

[0413]

[0414] [Chemistry 128]

[0415]

[0416] [Chemistry 129]

[0417]

[0418] [Chemistry 130]

[0419]

[0420] [Chemistry 131]

[0421]

[0422] [Chemistry 132]

[0423]

[0424] [Chemistry 133]

[0425]

[0426] [Chemistry 134]

[0427]

[0428] [Chemistry 135]

[0429]

[0430] [Chemistry 136]

[0431]

[0432] [Chemistry 137]

[0433]

[0434] [Chemistry 138]

[0435]

[0436] [Chemistry 139]

[0437]

[0438] [Chemistry 140]

[0439]

[0440] [Chemistry 141]

[0441]

[0442] Specific examples of the repeating unit b2 include those shown below, but are not limited to these. A Same as above.

[0443] [Chemistry 142]

[0444]

[0445] [Chemistry 143]

[0446]

[0447] [Chemistry 144]

[0448]

[0449] [Chemistry 145]

[0450]

[0451] [Chemistry 146]

[0452]

[0453] As for the repeating unit b1 or b2, in ArF lithography, those having a lactone ring as a polar group are more preferable, and in KrF lithography, EB lithography and EUV lithography, those having a phenol part are more preferable.

[0454] The base polymer may further contain a repeating unit represented by any of the following formulae (c1) to (c4) (hereinafter, also referred to as repeating units c1 to c4, respectively).

[0455] [Chemistry 147]

[0456]

[0457] In formulas (c1) to (c4), R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 is a single bond or a phenylene group. 2 **-C(=O)-OZ 21 -, **-C(=O)-NH-Z 21-or**-OZ 21 -.Z 21 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 3 Each is independently a single bond, phenylene, naphthylene or *-C(=O)-OZ 31 -.Z 31 Z is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. 4 Each is independently a single bond, ***-Z 41 -C(=O)-O-、***-C(=O)-NH-Z 41 -or***-OZ 41 -.Z 41 It is a alkylene group having 1 to 20 carbon atoms which may contain a hetero atom. 5 Each is independently a single bond, ****-Z 51 -C(=O)-O-、****-C(=O)-NH-Z 51 -or****-OZ 51 -.Z 51 It is a alkylene group having 1 to 20 carbon atoms which may contain a hetero atom. 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 61 -, *-C(=O)-N(H)-Z 61 -or*-OZ 61 -.Z 61 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group. * indicates an atomic bond to a carbon atom of the main chain. ** indicates an atomic bond to Z 1 *** indicates an atomic bond with Z 3 **** indicates the atomic bond with Z 4 of atoms.

[0458] Z 21 , Z 31 and Z 61The aliphatic alkylene group represented may be any of linear, branched or cyclic, and specific examples thereof include alkanediyl groups such as methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-2,2-diyl, butane-1,1-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-2,3-diyl, butane-1,4-diyl, 1,1-dimethylethane-1,2-diyl, pentane-1,5-diyl, 2-methylbutane-1,2-diyl, and hexane-1,6-diyl; cycloalkanediyl groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining these.

[0459] Z 41 and Z 51 The alkylene group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those shown below, but are not limited to these.

[0460] [Chemistry 148]

[0461]

[0462] In the formula, the dotted lines are atomic bonds.

[0463] In formula (c1), R 31 and R 32 Each is independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be any of linear, branched, and cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them, but aryl groups are more preferred. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. 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 sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0464] Again, R 31 and R 32 They may also be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring may be exemplified by the same as in the description of formula (cation-1) with respect to R c1 and R c2 The rings that can be formed by bonding with the sulfur atom to which they are bonded are the same as those exemplified above.

[0465] Specific examples of the cation in the repeating unit c1 include those shown below, but are not limited to these. A Same as above.

[0466] [Chemistry 149]

[0467]

[0468] [Chemistry 150]

[0469]

[0470] [Chemistry 151]

[0471]

[0472] [Chemistry 152]

[0473]

[0474] [Chemistry 153]

[0475]

[0476] [Chemistry 154]

[0477]

[0478] [Chemistry 155]

[0479]

[0480] In formula (c1), M- is a non-nucleophilic counter ion. Specific examples of the non-nucleophilic counter ions include halide ions such as chloride ions and bromide ions; fluoroalkyl sulfonate ions such as trifluoromethanesulfonate ions, 1,1,1-trifluoroethanesulfonate ions, and nonafluorobutanesulfonate ions; aryl sulfonate ions such as toluenesulfonate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, and 1,2,3,4,5-pentafluorobenzenesulfonate ions; alkyl sulfonate ions such as methanesulfonate ions and butanesulfonate ions; imide ions such as bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, and bis(perfluorobutylsulfonyl)imide ions; methide ions such as tris(trifluoromethylsulfonyl)methide ions and tris(perfluoroethylsulfonyl)methide ions; and the like.

[0481] Then, as specific examples of the aforementioned non-nucleophilic relative ions, there can be listed a sulfonate anion represented by the following formula (c1-1) in which the α-position is substituted with a fluorine atom and a sulfonate anion represented by the following formula (c1-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group.

[0482] [Chemistry 156]

[0483] R 33 —CF2—SO3 - (c1-1)

[0484]

[0485] In formula (c1-1), R 33 is a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, a hydrocarbon carbonyloxy group having 2 to 30 carbon atoms, or a hydrocarbon oxycarbonyl group having 2 to 30 carbon atoms, and the hydrocarbon group may also contain a halogen atom, an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbon radical of the aforementioned hydrocarbon group, hydrocarbon carbonyloxy group, and hydrocarbon oxycarbonyl group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include the following: fa1 The hydrocarbon groups exemplified are the same as those exemplified above.

[0486] In formula (c1-2), R 34 R is a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a hydrocarbon carbonyl group having 2 to 30 carbon atoms. The hydrocarbon group and hydrocarbon carbonyl group may contain a halogen atom, an ether bond, an ester bond, a carbonyl group, or a lactone ring. 35 is a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. The hydrocarbon radical of the hydrocarbon radical and hydrocarbon carbonyl group may be saturated or unsaturated, and may be straight-chain, branched or cyclic. Specific examples thereof include the following: fa1 The hydrocarbon groups represented by are the same as those exemplified above. 35 The trifluoromethyl group is more preferred.

[0487] Specific examples of the sulfonic acid anion represented by formula (c1-1) or (c1-2) include those shown below, but are not limited to these. 35 As mentioned above, Ac is acetyl.

[0488] [Chemistry 157]

[0489]

[0490] [Chemistry 158]

[0491]

[0492] [Chemistry 159]

[0493]

[0494] [Chemistry 160]

[0495]

[0496] [Chemistry 161]

[0497]

[0498] [Chemistry 162]

[0499]

[0500] [Chemistry 163]

[0501]

[0502] [Chemistry 164]

[0503]

[0504] [Chemistry 165]

[0505]

[0506] [Chemistry 166]

[0507]

[0508] In formula (C2) and (C3), L 1 It is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond. Among them, from the viewpoint of synthesis, an ether bond, an ester bond or a carbonyl group is more preferable, and an ester bond or a carbonyl group is more preferable.

[0509] In formula (c2), Rf 1 and Rf 2Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 1 and Rf 2 In order to increase the acid strength of the generated acid, it is more ideal that all of them are fluorine atoms. 3 and Rf 4 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 3 and Rf 4 It is preferred that at least one of the groups is a trifluoromethyl group.

[0510] In formula (c3), Rf 5 and Rf 6 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 5 and Rf 6 They are not hydrogen atoms at the same time. Among them, in order to improve the solvent solubility, Rf 5 and Rf 6 It is preferred that at least one of the groups is a trifluoromethyl group.

[0511] In formulae (c2) and (c3), d is an integer of 0 to 3, and 1 is preferable.

[0512] Specific examples of the anion of the repeating unit c2 include those shown below, but are not limited to these. A Same as above.

[0513] [Chemistry 167]

[0514]

[0515] [Chemistry 168]

[0516]

[0517] [Chemistry 169]

[0518]

[0519] [Chemistry 170]

[0520]

[0521] [Chemistry 171]

[0522]

[0523] [Chemistry 172]

[0524]

[0525] [Chemistry 173]

[0526]

[0527] Specific examples of the anion of the repeating unit c3 include those shown below, but are not limited to these. A Same as above.

[0528] [Chemistry 174]

[0529]

[0530] [Chemistry 175]

[0531]

[0532] [Chemistry 176]

[0533]

[0534] [Chemistry 177]

[0535]

[0536] [Chemistry 178]

[0537]

[0538] [Chemistry 179]

[0539]

[0540] [Chemistry 180]

[0541]

[0542] Specific examples of the anion of the repeating unit c4 include those shown below, but are not limited to these. A Same as above.

[0543] [Chemistry 181]

[0544]

[0545] In formulas (C2) to (C4), A + It is an onium cation. As the onium cation, there can be mentioned sulfonium cations, iodonium cations, ammonium cations, etc., but sulfonium cations and iodonium cations are more preferable. As for their specific structures, there can be mentioned the same ones as those exemplified for the cations represented by formulas (cation-1) to (cation-3).

[0546] Repeating units c1 to c4 function as photoacid generators. When a base polymer (ie, polymer-bonded acid generator) containing repeating units c1 to c4 is used, the chemically amplified resist composition of the present invention may or may not contain (D) a photoacid generator described later.

[0547] The base polymer may further contain a repeating unit having a structure in which a hydroxyl group is protected by an acid-labile group (hereinafter, also referred to as repeating unit d). The repeating unit d is not particularly limited as long as it has a structure in which one or two hydroxyl groups are protected and the protecting group is decomposed by the action of an acid to generate a hydroxyl group, but preferably it is represented by the following formula (d1).

[0548] [Chemistry 182]

[0549]

[0550] In formula (d1), R A Same as above. 41 It is a (e+1)-valent hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. 42 is an acid-labile group. e is an integer of 1-4.

[0551] In formula (d1), R 42 The acid-labile group represented by R may be any one that is deprotected by the action of an acid to generate a hydroxyl group. 42 The structure of is not particularly limited, and is preferably an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (d2), and particularly preferably an alkoxymethyl group represented by the following formula (d2).

[0552] [Chemistry 183]

[0553]

[0554] In the formula, * represents an atomic bond. 43 It is a hydrocarbon group having 1 to 15 carbon atoms.

[0555] Just R 42 Specific examples of the acid-labile group represented by the formula (d2), the alkoxymethyl group represented by the formula (d2), and the repeating unit d include the same ones as exemplified in the description of the repeating unit d described in JP-A-2020-111564.

[0556] The base polymer may further contain a repeating unit e derived from indene, benzofuran, benzothiophene, acenaphthene, chromone, coumarin, norbornadiene or a derivative thereof. Specific examples of the monomer providing the repeating unit e include those shown below, but are not limited thereto.

[0557] [Chemical 184]

[0558]

[0559] The aforementioned base polymer may further contain repeating unit f derived from indene, vinylpyridine, or vinylcarbazole.

[0560] In the polymer of the present invention, the content ratios of repeating units a1, a2, b1, b2, c1 to c4, d, e, and f are preferably 0 < a1 ≤ 0.8, 0 ≤ a2 ≤ 0.8, 0 < а1 + a2 ≤ 0.8, 0 ≤ b1 ≤ 0.6, 0 ≤ b2 ≤ 0.6, 0 ≤ b1 + b2 ≤ 0.6, 0 ≤ c1 ≤ 0.4, 0 ≤ c2 ≤ 0.4, 0 ≤ c3 ≤ 0.4, 0 ≤ c4 ≤ 0.4, 0 ≤ c1 + c2 + c3 + c4 ≤ 0.4, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.3, and 0 ≤ f ≤ 0.3, and more preferably 0 < a1 ≤ 0.7, 0 ≤ a2 ≤ 0.7, 0 < а1 + a2 ≤ 0.7, 0 ≤ b1 ≤ 0.5, 0 ≤ b2 ≤ 0.5, 0 ≤ b1 + b2 ≤ 0.5, 0 ≤ c1 ≤ 0.3, 0 ≤ c2 ≤ 0.3, 0 ≤ c3 ≤ 0.3, 0 ≤ c4 ≤ 0.3, 0 ≤ c1 + c2 + c3 + c4 ≤ 0.3, 0 ≤ d ≤ 0.3, 0 ≤ e ≤ 0.3, and 0 ≤ f ≤ 0.3. However, a1 + a2 + b1 + b2 + c1 + c2 + c3 + c4 + d + e + f = 1.0.

[0561] The weight average molecular weight (Mw) of the aforementioned polymer is preferably 1000 to 500000, and more preferably 3000 to 100000. If Mw falls within this range, sufficient etching resistance can be obtained, and there will be no concern about a decrease in resolution due to the inability to ensure a difference in dissolution rate before and after exposure. In addition, in the present invention, Mw is a polystyrene conversion measurement value obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent.

[0562] Then, regarding the molecular weight distribution (Mw / Mn) of the aforementioned polymer, since the influence of Mw / Mn tends to become larger as the pattern rule is miniaturized, in order to obtain a chemically amplified resist composition that can be ideally used for fine pattern sizes, a narrow dispersion with Mw / Mn of 1.0 to 2.0 is preferred. If it falls within the aforementioned range, there are fewer low molecular weight and high molecular weight polymers, and there will be no concern about finding foreign substances on the pattern or deterioration of the pattern shape after exposure.

[0563] To synthesize the aforementioned polymer, for example, the monomers providing the repeating units may be added with a radical polymerization initiator in an organic solvent and heated to carry out polymerization.

[0564] As for the organic solvent used in the polymerization, toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), PGMEA, GBL, etc. can be cited. As for the above-mentioned polymerization initiator, 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, etc. can be cited. The amount of these initiators added is preferably 0.01 to 25 mol% relative to the total amount of the 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 2 to 12 hours is more preferably considered from the perspective of production efficiency.

[0565] The aforementioned polymerization initiator can be added to the aforementioned monomer solution and supplied to the reactor, or the initiator solution can be prepared separately from the aforementioned monomer solution and then independently supplied to the reactor. During the standby time, there is a possibility that the polymerization reaction will be carried out due to the free radicals generated from the initiator and an ultra-high molecular body will be generated. Therefore, considering the viewpoint of quality management, it is more ideal that the monomer solution and the initiator solution are independently prepared and added dropwise. The acid-labile group can also be directly used by introducing it into the monomer, or it can be protected or partially protected after polymerization. In addition, for the adjustment of molecular weight, a known chain transfer agent such as dodecanethiol and 2-mercaptoethanol can also be used in combination. At this time, the addition amount of these chain transfer agents relative to the total amount of the monomers to be polymerized is preferably 0.01 to 20 mol%.

[0566] When the monomer contains a hydroxyl group, the hydroxyl group may be replaced with an acetal group such as ethoxyethoxy which is easily deprotected by acid during polymerization and then deprotected by weak acid and water after polymerization. Alternatively, the hydroxyl group may be replaced with an acetyl group, a formyl group, a pivaloyl group, etc. and then hydrolyzed with alkali after polymerization.

[0567] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, a free radical polymerization initiator is added to hydroxystyrene or hydroxyvinylnaphthalene and other monomers in an organic solvent and the polymerization is carried out by heating. However, acetoxystyrene or acetoxyvinylnaphthalene can also be used and the acetoxy group can be deprotected by alkaline hydrolysis after the polymerization to prepare polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0568] As the base for alkaline hydrolysis, aqueous ammonia, triethylamine, etc. can be used. The reaction temperature is preferably -20 to 100°C, more preferably 0 to 60°C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0569] The amount of each monomer in the monomer solution can be appropriately set, for example, so as to achieve the preferred content ratio of the repeating unit.

[0570] The polymer obtained by the above-mentioned production method can be used as the final product as a reaction solution obtained by the polymerization reaction, or as a powder obtained by adding the polymerization solution to a poor solvent and treating it as the final product through a purification step such as a reprecipitation method to obtain a powder. However, considering the operating efficiency and quality stability, it is more ideal to treat the powder obtained by the purification step into a solvent to form a polymer solution as the final product.

[0571] Specific examples of the solvent used in this case include ketones such as cyclohexanone and methyl-2-n-pentyl ketone described in paragraphs

[0144] to

[0145] of Japanese Patent Application Laid-Open No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; PGME, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, and propylene glycol dimethyl ether. , diethylene glycol dimethyl ether and other ethers; PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, 3-methoxypropionic acid methyl ester, 3-ethoxypropionic acid ethyl ester, tert-butyl acetate, tert-butyl propionate, propylene glycol monotert-butyl ether acetate and other esters; GBL and other lactones; DAA and other alcohols; diethylene glycol, propylene glycol, glycerol, 1,4-butanediol, 1,3-butanediol and other high-boiling point alcohol solvents; and their mixed solvents.

[0572] In the polymer solution, the concentration of the polymer is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0573] It is preferable to filter the reaction solution and polymer solution through a filter medium. Filtering through a filter medium can remove foreign matter and gel that may cause defects, which is effective in stabilizing quality.

[0574] As for the material of the filter material used in the aforementioned filter material filtration, materials such as fluorocarbon, cellulose, nylon, polyester, hydrocarbon can be cited, but in the filtering step of the chemical resist composition, the filter material formed by hydrocarbons such as fluorocarbon, polyethylene, polypropylene or nylon called Teflon (registered trademark) is more ideal. The pore size of the filter material can be appropriately selected in conjunction with the cleanliness set as the target, but it is more ideal to be less than 100nm, and more ideal to be less than 20nm. Again, these filter materials can be used alone, or multiple filter materials can be used in combination. As for the filtering method, the solution can be made to pass only once, but it is more ideal to circulate the solution and filter multiple times. The filtering step can be carried out in any order and number of times in the manufacturing step of the polymer, but it is more ideal to filter the reaction solution, polymer solution or both after the polymerization reaction.

[0575] The base polymer (C) may be used alone or in combination of two or more polymers having different composition ratios, Mw and / or Mw / Mn. In addition, the base polymer (C) may contain a hydrogenated ring-opening metathesis polymer in addition to the aforementioned polymers, and the polymer described in Japanese Patent Application Publication No. 2003-66612 may be used.

[0576] [(D) Photoacid generator]

[0577] The chemically amplified resist composition of the present invention has a photoacid generator and quencher as an essential component (A), but may also contain a photoacid generator as a component (D). The photoacid generator of the component (D) is not particularly limited as long as it is a compound that generates a strong acid when irradiated with high-energy rays. Specific examples of ideal photoacid generators include those represented by the following formula (2-1) or (2-2).

[0578] [Chemistry 185]

[0579]

[0580] In formula (2-1) and (2-2), R 101 ~R 105 are each independently a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. 101 , R 102 and R 103 Any two of them may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

[0581] Specific examples of the sulfonium cation represented by formula (2-1) include the same ones as those exemplified for the sulfonium cation represented by formula (cation-1), but are not limited thereto. Specific examples of the iodonium cation represented by formula (2-2) include the same ones as those exemplified for the iodonium cation represented by formula (cation-2), but are not limited thereto.

[0582] In formula (2-1) and (2-2), Xa - is an anion selected from the following formulae (2A) to (2D).

[0583] [Chemistry 186]

[0584]

[0585] In formula (2A), R fa is a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be straight chain, branched, or cyclic. Specific examples thereof include the following: fa1 The hydrocarbon groups exemplified are the same as those exemplified above.

[0586] The anion represented by the formula (2A) is preferably represented by the following formula (2A').

[0587]

[0588] In formula (2A'), R HF represents a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0589] R fa1 The hydrocarbon group may contain a hetero atom and has 1 to 38 carbon atoms. The hetero atom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and is more preferably an oxygen atom. The hydrocarbon group is preferably one having 6 to 30 carbon atoms from the viewpoint of obtaining high resolution when forming a fine pattern.

[0590] R fa1 The hydrocarbon group having 1 to 38 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl, pentadecyl, heptadecyl, and eicosyl; cyclic saturated hydrocarbon groups having 3 to 38 carbon atoms, such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated aliphatic hydrocarbon groups having 2 to 38 carbon atoms, such as allyl and 3-cyclohexenyl; aryl groups having 6 to 38 carbon atoms, such as phenyl, 1-naphthyl, and 2-naphthyl; aralkyl groups having 7 to 38 carbon atoms, such as benzyl and diphenylmethyl; and groups obtained by combining these.

[0591] Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. 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 sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like. Specific examples of the hydrocarbon group containing a heteroatom include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, 5-hydroxy-1-adamantyl, 5-tert-butylcarbonyloxy-1-adamantyl, 4-oxatricyclo[4.2.1.0 3,7 ]nonan-5-one-2-yl, 3-oxocyclohexyl, etc.

[0592] For details on the synthesis of sulfonium salts having an anion represented by formula (2A'), see 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 also be preferably used.

[0593] Specific examples of the anion represented by the formula (2A) include the same ones as exemplified for the anions represented by the formulae (c1-1) and (c1-2).

[0594] In formula (2B), R fb1 and R fb2 Each is independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be straight chain, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are the same as those exemplified above. fb1 and R fb2 In particular, R is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 They can also bond to each other and to the groups they bond to (-CF2-SO2-N - -SO2-CF2-) together to form a ring, at this time, R fb1 and Rfb2 The groups that can be obtained by bonding to each other are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0595] In formula (2C), R fc1 , R fc2 and R fc3 Each is independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be straight chain, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are the same as those exemplified above. fc1 , R fc2 and R fc3 In particular, R is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 They can also bond to each other and to the groups they bond to (-CF2-SO2-C - -SO2-CF2-) together to form a ring, at this time, R fc1 and R fc2 The groups that can be obtained by bonding to each other are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0596] In formula (2D), R fd is a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be straight chain, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups exemplified are the same as those exemplified above.

[0597] For details on the synthesis of the sulfonium salt having an anion represented by the formula (2D), see Japanese Patent Application Laid-Open Nos. 2010-215608 and 2014-133723.

[0598] Specific examples of the anion represented by the formula (2D) include those shown below, but are not limited to these.

[0599] [Chemistry 187]

[0600]

[0601] [Chemistry 188]

[0602]

[0603] Examples of the non-nucleophilic counter ion include anions having an aromatic ring substituted with an iodine atom or a bromine atom. Specific examples of such anions include those represented by the following formula (2E).

[0604] [Chemistry 189]

[0605]

[0606] In formula (2E), x is an integer satisfying 1≤x≤3. y and z are integers satisfying 1≤y≤5, 0≤z≤3 and 1≤y+z≤5. y is preferably an integer satisfying 1≤y≤3, more preferably 2 or 3. z is preferably an integer satisfying 0≤z≤2.

[0607] In formula (2E), X BI is an iodine atom or a bromine atom, and when x and / or y is 2 or more, they may be the same as or different from each other.

[0608] In formula (2E), L 11 It is a single bond, an ether bond, or an ester bond, or a saturated alkylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated alkylene group may be linear, branched, or cyclic.

[0609] In formula (2E), L 12 When x is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms. When x is 2 or 3, it is a (x+1)-valent linking group having 1 to 20 carbon atoms. The linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.

[0610] In formula (2E), R fe is a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbonoxy group having 1 to 20 carbon atoms, a hydrocarboncarbonyl group having 2 to 20 carbon atoms, a hydrocarbonoxycarbonyl group having 2 to 10 carbon atoms, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms or a hydrocarbonsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group or an ether bond, or -N(R feA )(R feB )、-N(R feC )-C(=O)-R feD or -N(R feC )-C(=O)-OR feD . R feA and R feB Each R is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. feC R is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. feDIt is an aliphatic hydrocarbon group having 1 to 16 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon group may be saturated or unsaturated, and may be any of a straight chain, a branched shape, or a cyclic shape. The aforementioned hydrocarbon group, hydrocarbon oxy group, hydrocarbon carbonyl group, hydrocarbon oxycarbonyl group, hydrocarbon carbonyloxy group, and hydrocarbon sulfonyloxy group may be any of a straight chain, a branched shape, or a cyclic shape. When x and / or z is 2 or more, each R fe They can be the same or different.

[0611] Among these, R fe For hydroxyl, -N(R feC )-C(=O)-R feD 、-N(R feC )-C(=O)-OR feD , fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group and the like are preferred.

[0612] In formula (2E), Rf 11 ~Rf 14 Each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them is a fluorine atom or a trifluoromethyl group. 11 With Rf 12 They may also be combined to form a carbonyl group. In particular, Rf 13 and Rf 14 At the same time, a fluorine atom is more preferable.

[0613] Specific examples of the anion of the onium salt represented by formula (2E) include those shown below, but are not limited to these. BI Same as above.

[0614] [Chemistry 190]

[0615]

[0616] [Chemistry 191]

[0617]

[0618] [Chemistry 192]

[0619]

[0620] [Chemistry 193]

[0621]

[0622] [Chemistry 194]

[0623]

[0624] [Chemistry 195]

[0625]

[0626] [Chemistry 196]

[0627]

[0628] [Chemistry 197]

[0629]

[0630] [Chemistry 198]

[0631]

[0632] [Chemistry 199]

[0633]

[0634] [Chemistry 200]

[0635]

[0636] [Chemistry 201]

[0637]

[0638] [Chemistry 202]

[0639]

[0640] [Chemistry 203]

[0641]

[0642] [Chemistry 204]

[0643]

[0644] [Chemistry 205]

[0645]

[0646] [Chemistry 206]

[0647]

[0648] [Chemistry 207]

[0649]

[0650] [Chemistry 208]

[0651]

[0652] [Chemistry 209]

[0653]

[0654] [Chemistry 210]

[0655]

[0656] [Chemistry 211]

[0657]

[0658] [Chemistry 212]

[0659]

[0660] As for the aforementioned non-nucleophilic counter ion, a fluorobenzenesulfonic acid anion bonded to an aromatic group containing an iodine atom described in Japanese Patent No. 6648726, an anion having a mechanism of decomposition by acid described in International Publication No. 2021 / 200056 and Japanese Patent Application No. 2021-070692, an anion having a cyclic ether group described in Japanese Patent Application No. 2018-180525 and Japanese Patent Application No. 2021-35935, and an anion described in Japanese Patent Application No. 2018-092159 can also be used.

[0661] As for the aforementioned non-nucleophilic counter ions, anions of bulky benzenesulfonic acid derivatives containing no fluorine atoms described in Japanese Patent Publication Nos. 2006-276759, 2015-117200, 2016-65016, and 2019-202974, and benzenesulfonic acid anions containing no fluorine atoms and bonded to an aromatic group containing an iodine atom described in Japanese Patent No. 6645464, and alkylsulfonic acid anions can also be used.

[0662] As for the aforementioned non-nucleophilic counter ion, the anion of the disulfonic acid described in JP-A-2015-206932, the anion of a sulfonic acid on one side and a sulfonamide or sulfonylimide different therefrom on the other side described in International Publication No. 2020 / 158366, and the anion of a sulfonic acid on one side and a carboxylic acid on the other side described in JP-A-2015-024989 can also be used.

[0663] Moreover, the photoacid generator of the component (D) is preferably represented by the following formula (3).

[0664] [Chemistry 213]

[0665]

[0666] In formula (3), R 201 and R 202 Each independently represents a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. 203 is a alkylene group having 1 to 30 carbon atoms which may contain a hetero atom. 201 , R 202 and R 203 Any two of them may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

[0667] R 201 and R 202 The hydrocarbon group having 1 to 30 carbon atoms represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, such as decyl and adamantyl; aryl groups having 6 to 30 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl and anthracenyl; groups derived from combinations thereof, etc. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing hetero atoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. 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 sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0668] R 203The alkylene group having 1 to 30 carbon atoms represented by the invention may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, Alkanediyl groups having 1 to 30 carbon atoms, such as heptadecanediyl group, etc.; cyclic saturated alkylene groups having 3 to 30 carbon atoms, such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, adamantanediyl group, etc.; arylene groups having 6 to 30 carbon atoms, such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, tert-butylnaphthylene group, etc.; Furthermore, part or all of the hydrogen atoms of the aforementioned alkylene group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned alkylene group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, 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 sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. may be contained. As for the aforementioned hetero atom, an oxygen atom is preferably used.

[0669] In formula (3), L A is a single bond, an ether bond, or an alkylene group having 1 to 20 carbon atoms which may contain a hetero atom. The alkylene group may be saturated or unsaturated, and may be straight chain, branched, or cyclic. Specific examples thereof include: 203 The alkylene groups exemplified are the same as those exemplified above.

[0670] In formula (3), X a , X b , X c and X d Each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group. a , X b , X c and X d At least one of them is a fluorine atom or a trifluoromethyl group.

[0671] The photoacid generator represented by the formula (3) is preferably represented by the following formula (3').

[0672] [Chemistry 214]

[0673]

[0674] In formula (3'), L A Same as above. X e R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 Each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are the same as those exemplified above. p1 and p2 are each independently an integer of 0-5, and p3 is an integer of 0-4.

[0675] Examples of the photo-acid generator represented by formula (3) include the same ones as exemplified for the photo-acid generator represented by formula (2) in JP-A-2017-026980.

[0676] Among the other photoacid generators mentioned above, those containing anions represented by formula (2A') or (2D) are particularly preferred because they have low acid diffusion and excellent solubility in solvents. Also, those represented by formula (3') are particularly preferred because they have extremely low acid diffusion.

[0677] When the chemically amplified resist composition of the present invention contains a photoacid generator (D), its content is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass relative to 80 parts by mass of the base polymer (C). If the amount of the photoacid generator added as component (D) falls within the aforementioned range, the resolution is good, and there is no concern of foreign matter after the development or peeling of the resist film, so it is more ideal. The photoacid generator of component (D) can be used alone or in combination of two or more.

[0678] [(E) Quencher]

[0679] The chemically amplified resist composition of the present invention contains the photoacid generator and quencher as the component (A) as an essential component, but may also contain a quencher as the component (E).

[0680] Examples of the quencher (E) include onium salts represented by the following formula (4) or (5).

[0681] [Chemistry 215]

[0682]

[0683] In formula (4), R q1 is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom, but excludes a case where the hydrogen atom bonded to the carbon atom at the α-position of the sulfonic acid group is substituted with a fluorine atom or a fluoroalkyl group. q2 It is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom.

[0684] Just R q1 Specific examples of the hydrocarbon group having 1 to 40 carbon atoms include alkyl groups having 1 to 40 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbon groups with 3 to 40 carbon atoms such as decyl and adamantyl; aryl groups with 6 to 40 carbon atoms such as phenyl, naphthyl, anthracenyl, etc. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and part of -CH2- of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may be contained.

[0685] Just R q2 Specifically, in addition to R q1 In addition to the substituents exemplified in the specific examples of , fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl can be mentioned.

[0686] Specific examples of the anion of the onium salt represented by the formula (4) include those shown below, but are not limited to these.

[0687] [Chemistry 216]

[0688]

[0689] [Chemistry 217]

[0690]

[0691] [Chemistry 218]

[0692]

[0693] [Chemistry 219]

[0694]

[0695] Specific examples of the anion of the onium salt represented by the formula (5) include those shown below, but are not limited to these.

[0696] [Chemistry 220]

[0697]

[0698] [Chemistry 221]

[0699]

[0700] [Chemistry 222]

[0701]

[0702] In formula (4) and (5), Mq + The onium cation is preferably a sulfonium cation represented by the above formula (cation-1), an iodonium cation represented by the above formula (cation-2), or an ammonium cation represented by the above formula (cation-3).

[0703] As for the specific example of the onium salt represented by formula (4) or (5), any combination of the above-mentioned anions and cations can be cited. In addition, these onium salts are easily prepared by ion exchange reactions using known organic chemical methods. Regarding ion exchange reactions, for example, Japanese Patent Publication No. 2007-145797 can be used as a reference.

[0704] The onium salt represented by formula (4) or (5) functions as a quencher in the chemically amplified resist composition of the present invention. This is because each counter anion of the onium salt is a conjugate base of a weak acid. Here, the so-called weak acid refers to an acid that is insufficient to deprotect the acid-labile group of the unit containing an acid-labile group used in the base polymer. The onium salt represented by formula (4) or (5) 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 sulfonic acid fluorinated at the α-position as a counter anion. That is, when an onium salt that generates a strong acid such as sulfonic acid fluorinated at the α-position is used in combination with an onium salt that generates a weak acid such as sulfonic acid or carboxylic acid that is not fluorinated, if the strong acid generated from the photoacid generator due to high-energy ray irradiation collides with the unreacted onium salt having a weak acid anion, the weak acid is released due to salt exchange, and an onium salt having a strong acid anion is generated. Through this process, the strong acid is exchanged for a weaker acid with lower catalytic ability, so the acid is apparently deactivated and the acid diffusion can be controlled.

[0705] In addition, as for the (E) quencher, an onium salt having a sulfonium cation and a phenoxide anion site in the same molecule as described in Japanese Patent No. 6848776 can be used, and an onium salt having a sulfonium cation and a carboxylate anion site in the same molecule as described in Japanese Patent No. 6583136 and Japanese Patent Application Publication No. 2020-200311, and an onium salt having an iodonium cation and a carboxylate anion site in the same molecule as described in Japanese Patent No. 6274755 can also be used.

[0706] Here, when the photoacid generator that generates a strong acid is an onium salt, it is considered that, although the strong acid generated by high-energy ray irradiation is exchanged for a weak acid as described above, on the other hand, the weak acid generated by high-energy ray irradiation and the unreacted onium salt that generates a strong acid collide with each other and salt exchange is difficult to perform. This is because the onium cation easily forms an ion pair with the anion of a stronger acid.

[0707] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (2) or (3) as the (E) quencher, its content is preferably 0.1 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass relative to 80 parts by mass of the (C) base polymer. If the onium salt quencher of the (E) component falls within the above range, the resolution is good and there is no significant decrease in sensitivity, so it is more ideal. The onium salt represented by formula (2) or (3) can be used alone or in combination of two or more.

[0708] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as (E) a quencher. Examples of the nitrogen-containing compound of the component (E) include primary, secondary or tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Publication No. 2008-111103, and in particular, amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate bond. In addition, examples include compounds described in Japanese Patent No. 3790649, and compounds obtained by protecting primary or secondary amines with carbamate groups.

[0709] In addition, a sulfonium sulfonate salt having a nitrogen-containing substituent may also be used as the nitrogen-containing compound. Such a compound functions as a quencher in the unexposed portion, and the exposed portion loses the quencher performance due to neutralization with the acid generated by itself, and functions as a so-called photodisintegration base. By using a photodisintegration base, the contrast between the exposed portion and the unexposed portion can be made stronger. As for the photodisintegration base, for example, Japanese Patent Publication No. 2009-109595, Japanese Patent Publication No. 2012-46501, etc. can be used as reference.

[0710] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as the (E) quencher, its content is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass, relative to 80 parts by mass of the (C) base polymer. The nitrogen-containing compound may be used alone or in combination of two or more.

[0711] [(F) Surfactant]

[0712] The chemically amplified resist composition of the present invention may further contain (F) a surfactant. As for the surfactant of the component (F), it is preferably a surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer, or a surfactant that is insoluble or poorly soluble in water and an alkaline developer. As for such a surfactant, reference may be made to those described in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2011-16746.

[0713] As for the surfactants that are insoluble or poorly soluble in water and alkali developer, among the surfactants described in the aforementioned gazette, FC-4430 (manufactured by 3M Co., Ltd.), Surflon (registered trademark) S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Olfine (registered trademark) E1004 (manufactured by Nissin Chemical Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and the oxetane ring-opening polymer represented by the following formula (surf-1) are particularly preferable.

[0714] [Chemistry 223]

[0715]

[0716] Here, R, Rf, A, B, C, m, and n are irrelevant to the above description and apply only to formula (surf-1). R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. As for the aforementioned aliphatic group, for a divalent one, ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentylene, etc. can be listed, and for a trivalent or tetravalent one, the following can be listed.

[0717] [Chemistry 224]

[0718]

[0719] In the formula, the dotted lines are atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.

[0720] Among these, 1,4-butylene group, 2,2-dimethyl-1,3-propylene group and the like are particularly preferred.

[0721] Rf is trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. m is an integer of 0 to 3, n is an integer of 1 to 4, and the sum of n and m is the valence of R and is an integer of 2 to 4. A is 1. B is an integer of 2 to 25, preferably an integer of 4 to 20. C is an integer of 0 to 10, preferably 0 or 1. In addition, the arrangement of the constituent units in formula (surf-1) is not specified, and they may be bonded in blocks or randomly. For details on the manufacture of surfactants based on partially fluorinated oxetane ring-opening polymers, see the specification of U.S. Patent No. 5,650,483, etc.

[0722] A surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer has the function of reducing water penetration and leaching by being oriented to the surface of the resist film when no resist protective film is used in ArF immersion lithography. Therefore, it is useful in terms of suppressing the elution of water-soluble components from the resist film and reducing damage to the exposure device. In addition, it is useful because it can be dissolved during development with an alkaline aqueous solution after exposure and after PEB, and it is not easy to become a foreign matter that may cause defects. This type of surfactant is insoluble or poorly soluble in water and soluble in an alkaline developer. It is a polymer-type surfactant, also known as a hydrophobic resin, and is particularly ideal for having high water repellency and improving water sliding properties.

[0723] Specific examples of such polymeric surfactants include those containing at least one type of repeating units selected from the group consisting of the repeating units represented by the following formulae (6A) to (6E).

[0724] [Chemistry 225]

[0725]

[0726] In formulas (6A) to (6E), R B W is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 It is -CH2-, -CH2CH2-, -O- or two -H separated from each other. s1 Each R is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. s2 is a single bond, or a linear or branched alkylene group having 1 to 5 carbon atoms. s3 Each R is independently a hydrogen atom, a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group. s3 When it is a hydrocarbon group or a fluorinated hydrocarbon group, there may be an ether bond or a carbonyl group between the carbon-carbon bonds. s4 is a (u+1)-valent hydrocarbon group or a fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer of 1 to 3. s5 are each independently a hydrogen atom, or -C(=O)-OR sa Represents a group.sa is a fluorinated hydrocarbon group having 1 to 20 carbon atoms. s6 It is a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, and an ether bond or a carbonyl group may be present between carbon-carbon bonds.

[0727] R s1 The hydrocarbon group represented by is preferably a saturated hydrocarbon group, and may be any of a straight chain, a branched, or a cyclic type. Specific examples thereof include 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; and cyclic saturated hydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl. Among these, those having 1 to 6 carbon atoms are more preferred.

[0728] R s2 The alkylene group represented by is preferably a saturated alkylene group, and may be any of a linear, branched, or cyclic type. Specific examples thereof include methylene, ethylene, propylene, butylene, and pentylene.

[0729] R s3 or R s6 The hydrocarbon group represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include saturated hydrocarbon groups, alkenyl groups, alkynyl groups, and other aliphatic unsaturated hydrocarbon groups, but saturated hydrocarbon groups are more preferred. s1 In addition to the hydrocarbon groups exemplified above, examples include n-undecyl, n-dodecyl, tridecyl, tetradecyl, pentadecyl, and the like. s3 or R s6 As for the fluorinated hydrocarbon groups represented by , some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbon groups are substituted with fluorine atoms. As mentioned above, these carbon-carbon bonds may be separated by ether bonds or carbonyl groups.

[0730] Just R s3 Specific examples of the acid-labile group represented by include groups represented by the above formulae (AL-3) to (AL-5), trialkylsilyl groups in which each alkyl group is an alkyl group having 1 to 6 carbon atoms, and alkyl groups containing an oxo group having 4 to 20 carbon atoms.

[0731] R s4 The (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group represented by may be linear, branched or cyclic, and specific examples thereof include groups obtained by removing u hydrogen atoms from the above-mentioned hydrocarbon group or fluorinated hydrocarbon group.

[0732] R saThe fluorinated hydrocarbon group represented by is preferably saturated, and may be any of linear, branched, and cyclic. Specific examples thereof include those in which a part or all of the hydrogen atoms of the aforementioned hydrocarbon groups are substituted by fluorine atoms, such as trifluoromethyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoro-1-propyl, 3,3,3-trifluoro-2-propyl, 2,2,3,3-tetrafluoropropyl, 1,1,1,3,3,3-hexafluoroisopropyl, 2,2,3,3,4,4,4-heptafluorobutyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl, 2-(perfluorobutyl)ethyl, 2-(perfluorohexyl)ethyl, 2-(perfluorooctyl)ethyl, 2-(perfluorodecyl)ethyl, etc.

[0733] Specific examples of the repeating units represented by formulae (6A) to (6E) include those shown below, but are not limited to these. B Same as above.

[0734] [Chemistry 226]

[0735]

[0736] [Chemistry 227]

[0737]

[0738] [Chemistry 228]

[0739]

[0740] [Chemistry 229]

[0741]

[0742] [Chemistry 230]

[0743]

[0744] [Chemistry 231]

[0745]

[0746] The aforementioned polymeric surfactant may further contain other repeating units other than the repeating units represented by formulas (6A) to (6E). As for other repeating units, examples include repeating units obtained from methacrylic acid, α-trifluoromethylacrylic acid derivatives, etc. In the polymeric surfactant, the content of the repeating units represented by formulas (6A) to (6E) is preferably 20 mol% or more, more preferably 60 mol% or more, and even more preferably 100 mol% in the total repeating units.

[0747] The Mw of the polymer surfactant is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. The Mw / Mn is preferably 1.0 to 2.0, more preferably 1.0 to 1.6.

[0748] As for the method of synthesizing the aforementioned polymer surfactant, there can be cited a method in which a monomer having an unsaturated bond that provides a repeating unit represented by formula (6A) to (6E) and other repeating units as required is added with a free radical initiator to an organic solvent and heated to polymerize it. As for the organic solvent used in the polymerization, there can be cited toluene, benzene, THF, diethyl ether, dioxane, etc. As for the polymerization initiator, there can be cited to be AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, etc. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. The acid-labile group can be used directly introduced into the monomer, or it can be protected or partially protected after polymerization.

[0749] When synthesizing the aforementioned polymer surfactant, a known chain transfer agent such as dodecanethiol or 2-mercaptoethanol may be used to adjust the molecular weight. In this case, the amount of the chain transfer agent added is preferably 0.01 to 10 mol% relative to the total molar number of the monomers to be polymerized.

[0750] When the chemically amplified resist composition of the present invention contains a surfactant (F), the content thereof is preferably 0.1 to 50 parts by mass, and more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the base polymer (C). If the content of the surfactant (F) is 0.1 parts by mass or more, the receding contact angle between the resist film surface and water will be sufficiently improved, and if it is 50 parts by mass or less, the dissolution rate of the resist film surface to the developer is low, and the height of the fine pattern formed will be sufficiently ensured. The surfactant (F) may be used alone or in combination of two or more.

[0751] [(G) Other ingredients]

[0752] The chemically amplified resist composition of the present invention may also contain compounds that decompose and generate acid due to acid (acid multiplication compounds), organic acid derivatives, fluorine-substituted alcohols, compounds with a Mw of 3000 or less that change solubility in a developer due to the action of acid (dissolution inhibitors), etc. As for the aforementioned acid multiplication compounds, reference may be made to the compounds described in Japanese Patent Application Laid-Open No. 2009-269953 or Japanese Patent Application Laid-Open No. 2010-215608. When the aforementioned acid multiplication compound is included, its content is preferably 0 to 5 parts by weight, and more preferably 0 to 3 parts by weight relative to 80 parts by weight of the (C) base polymer. If the content is too much, it is difficult to control the diffusion of the acid, and there is a possibility that the resolution and pattern shape may be degraded. As for the aforementioned organic acid derivatives, fluorine-substituted alcohols and dissolution inhibitors, reference may be made to the compounds described in Japanese Patent Application Laid-Open No. 2009-269953 or Japanese Patent Application Laid-Open No. 2010-215608.

[0753] [Pattern Formation Method]

[0754] The pattern forming method of the present invention comprises the following steps: forming a resist film on a substrate using the chemically amplified resist composition; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

[0755] As for the aforementioned substrate, for example, 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.) can be used.

[0756] The resist film can be formed, for example, by applying the chemically amplified resist composition by spin coating or the like so that the film thickness is preferably 0.05 to 2 μm, and pre-baking it on a hot plate at a temperature of preferably 60 to 150° C. for 1 to 10 minutes, more preferably 80 to 140° C. for 1 to 5 minutes.

[0757] As for the high energy radiation used for exposure of the resist film, i-ray, KrF excimer laser, ArF excimer laser, EB, EUV, etc. can be listed. When using KrF excimer laser, ArF excimer laser or EUV, a mask for forming a target pattern can be used to preferably expose the film at an exposure dose of 1 to 200 mJ / cm 2 , more ideally 10 to 100 mJ / cm 2 When using EB, a mask for forming the target pattern or directly using an exposure dose of 1 to 300 μC / cm2 , more ideally 10 to 200 μC / cm 2 way of irradiation.

[0758] In addition to the usual exposure method, the exposure may be performed by an immersion method in which a liquid having a refractive index of 1.0 or more is interposed between the resist film and the projection lens. In this case, a protective film insoluble in water may be used.

[0759] The aforementioned protective film insoluble in water is used to prevent elution from the resist film and improve the water sliding property of the film surface, and can be roughly divided into two types. One of them is an organic solvent stripping type that must be stripped before alkaline aqueous solution development by an organic solvent that does not dissolve the resist film, and the other is an alkaline aqueous solution soluble type that is soluble in an alkaline developer and removes the protective film at the same time when the soluble part of the resist film is removed. The latter is particularly preferably a material based on a polymer having a 1,1,1,3,3,3-hexafluoro-2-propanol residue that is insoluble in water and soluble in an alkaline developer, and that is soluble in an alcohol solvent with a carbon number of 4 or more, an ether solvent with a carbon number of 8 to 12, and a mixed solvent thereof. It can also be set to a material in which the aforementioned surfactant that is insoluble in water and soluble in an alkaline developer is dissolved in an alcohol solvent with a carbon number of 4 or more, an ether solvent with a carbon number of 8 to 12, or a mixed solvent thereof.

[0760] After the exposure, PEB may be performed. PEB can be performed, for example, by heating on a hot plate at 60 to 150° C. for 1 to 5 minutes, more preferably 80 to 140° C. for 1 to 3 minutes.

[0761] As for development, for example, a developer containing an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) in an ideal concentration of 0.1 to 5% by mass, more preferably 2 to 3% by mass, is used, and development is performed using general methods such as dipping, puddle, and spraying for an ideal period of 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, whereby the exposed portion is dissolved and a target pattern is formed on the substrate.

[0762] After the resist film is formed, the acid generator and the like from the film surface may be extracted or particles may be washed away by washing with pure water, or water remaining on the film after exposure may be removed.

[0763] Then, the pattern formation can also be performed by a double patterning method. As for the double patterning method, examples include a trench method in which a substrate with a 1:3 trench pattern is processed by the first exposure and etching, and then the position is shifted and a 1:3 trench pattern is formed by the second exposure to form a 1:1 pattern; and a line method in which a first substrate with a 1:3 isolation pattern is processed by the first exposure and etching, and then the position is shifted and a second substrate with a 1:3 isolation pattern formed under the first substrate is processed by the second exposure to form a 1:1 pattern with half the pitch.

[0764] In the pattern forming method of the present invention, a negative tone development method in which an organic solvent is used as a developer to dissolve the unexposed portion instead of the alkaline aqueous solution may be used. In the organic solvent development, as the developer, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl croton ... Ethyl beanate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0765] Example

[0766] Hereinafter, the present invention will be specifically described by showing synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples. In addition, the following apparatuses were used.

[0767] IR: NICOLET 6700 manufactured by Thermo Fisher Scientific

[0768] · 1 H-NMR: ECA-500 manufactured by JEOL Ltd.

[0769] ·MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0770] [1] Synthesis of onium salts

[0771] [Example 1-1] Synthesis of Onium Salt NPAG-1

[0772] [Chemistry 232]

[0773]

[0774] (1) Synthesis of intermediate In-1

[0775] In a nitrogen environment, compound SM-1 (10.2 g), compound SM-2 (7.9 g), 4-dimethylaminopyridine (DMAP) (0.5 g) and dichloromethane (50 g) were fed into a reaction vessel and cooled with an ice bath. While maintaining the temperature in the reaction vessel below 20°C, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (9.2 g) was directly added in the form of a powder. After addition, the temperature was raised to room temperature and matured for 12 hours. After maturation, water was added to stop the reaction, and the usual aqueous work-up was performed to distill off the solvent to obtain the intermediate In-1 (yield 16.4 g, yield 95%) in the form of an oil.

[0776] (2) Synthesis of onium salt NPAG-1

[0777] Under nitrogen atmosphere, the intermediate In-2 (19.9 g) and the compound SM-3 (13.4 g) were mixed with dichloromethane (100 g) and water (80 g) and stirred at room temperature for 2 hours. After stirring, the mixture was subjected to a conventional aqueous work-up, the solvent was distilled off, and diisopropyl ether was added and washed to obtain the onium salt NSQ-1 (yield 20.6 g, yield 86%) as an oil.

[0778] The IR spectrum data and TOF-MS results of the onium salt NPAG-1 are shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 1 In addition, the NMR spectrum ( 1 In the result of H-NMR / DMSO-d6), dichloromethane used as a solvent and diisopropyl ether used for washing were detected.

[0779] IR(D-ATR):ν=3079,2979,2957,2858,1780,1696,1590,1478,1460,1445,1415,1367,1333,1317,1274,123 9,1223,1204,1173,1147,1123,1087,1042,973,946,930,883,814,789,772,760,723,683,649,617,595cm -1 .

[0780] MALDI TOF-MS:POSITIVE M +277 (equivalent to C 18 H 13 OS + )

[0781] NEGATIVE M - 472 (equivalent to C 15 H 20 F6NO7S - )

[0782] [Examples 1-2 to 1-7] Synthesis of Onium Salts NPAG-2 to NPAG-7

[0783] Onium salts NPAG-2 to NPAG-7 represented by the following formulae were synthesized using corresponding raw materials and known organic chemical reactions.

[0784] [Chemistry 233]

[0785]

[0786] The IR spectrum data and TOF-MS results of the onium salt NPAG-2 are shown below. 1 The results of H-NMR / DMSO-d6 are shown in Figure 2 In addition, the NMR spectrum ( 1 In the result of H-NMR / DMSO-d6), dichloromethane used as a solvent and diisopropyl ether used for washing were detected.

[0787] IR(D-ATR):ν=3055,2965,2870,1778,1694,1684,1588,1491,1464,1408,1367,1329,1307,1237, 1225,1198,1174,1145,1073,1039,971,947,926,867,837,762,725,678,658,621,606,597,567cm -1 .

[0788] MALDI TOF-MS:POSITIVE M + 431 (equivalent to C 30 H 39 S + )

[0789] NEGATIVE M - 472 (equivalent to C 15 H 20 F6NO7S - )

[0790] [Synthesis Example] Synthesis of base polymers (polymers P-1 to P-5)

[0791] The monomers were combined and copolymerized in MEK as a solvent, and then added to hexane. The precipitated solid was washed with hexane, isolated, and dried to obtain base polymers (polymers P-1 to P-5) with the following composition. The composition of the obtained base polymer is determined by 1 H-NMR, Mw, and Mw / Mn were confirmed by GPC (solvent: DMF, standard: polystyrene).

[0792] [Chemistry 234]

[0793]

[0794] [3] Preparation of chemically amplified resist compositions

[0795] [Examples 2-1 to 2-20, Comparative Examples 1-1 to 1-16]

[0796] The onium salts of the present invention (NPAG-1 to NPAG-7), comparative onium salts (cPAG-A to cPAG-D), base polymers (P-1 to P-5), photoacid generators (PAG-1, PAG-2) and quenchers (SQ-A, AQ-A) having the compositions shown in the following Tables 1 and 2 were dissolved in a solvent containing 100 ppm of FC-4430 manufactured by 3M Company as a surfactant to prepare a solution, and the solution was filtered through a 0.2 μm Teflon (registered trademark) filter material to prepare a chemically amplified resist composition.

[0797] In Tables 1 and 2, the components are as follows.

[0798] Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0799] DAA (Diacetone Alcohol)

[0800] ·Comparative onium salts: cPAG-A to cPAG-D

[0801] [Chemistry 235]

[0802]

[0803] Photoacid generator: PAG-1, PAG-2

[0804] [Chemistry 236]

[0805]

[0806] Quencher: SQ-A, AQ-A

[0807] [Chemistry 237]

[0808]

[0809] [Table 1]

[0810]

[0811]

[0812] [Table 2]

[0813]

[0814] [4]EUV lithography evaluation (1)

[0815] [Examples 3-1 to 3-20, Comparative Examples 2-1 to 2-16]

[0816] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-16) was spin-coated on a Si substrate on which a silicon-containing spin-coating hard mask SHB-A940 (containing 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and pre-baked using a hot plate at 100° C. for 60 seconds to prepare a resist film with a film thickness of 50 nm. The resist film was exposed using an EUV scanning exposure machine NXE3400 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, dipole illumination) while changing the exposure amount and focus (exposure amount pitch: 1 mJ / cm 2 , focal pitch: 0.020 μm) while exposing an LS pattern with a size of 18 nm and a pitch of 36 nm on the wafer, and after exposure, PEB was performed for 60 seconds at the temperature shown in Tables 3 and 4. Thereafter, immersion development was performed for 30 seconds with a 2.38 mass % TMAH aqueous solution, and then rinsed with a rinse material containing a surfactant, and then spin-dried to obtain a positive pattern.

[0817] The developed LS pattern was observed with CD-SEM (CG6300) manufactured by Hitachi Advanced Technologies Co., Ltd., and the sensitivity, EL, LWR, DOF and collapse limit were evaluated according to the following methods. The results are shown in Tables 3 and 4.

[0818] [Sensitivity evaluation]

[0819] The optimum exposure Eop (mJ / cm2) for obtaining a LS pattern with a line width of 18 nm and a pitch of 36 nm was calculated. 2 ) and define it as sensitivity.

[0820] [EL evaluation]

[0821] The EL (unit: %) was calculated from the exposure amount formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm interval width in the LS pattern described above by the following formula. The larger the value, the better the performance.

[0822] EL(%)=(|E1-E2| / E op )×100

[0823] E1: Optimal exposure for LS pattern with line width of 16.2nm and pitch of 36nm

[0824] E2: Optimal exposure for LS pattern with line width of 19.8nm and pitch of 36nm

[0825] E op : Optimal exposure for LS pattern with line width of 18nm and pitch of 36nm

[0826] [LWR evaluation]

[0827] For the LS pattern obtained by irradiation with Eop, the dimensions of 10 points in the long side direction of the line are measured, and the value (3σ) tripled by the standard deviation (σ) is calculated as LWR. The smaller this value is, the smaller the roughness is, and the more uniform the line width pattern can be obtained.

[0828] [DOF evaluation]

[0829] As the focal depth evaluation, the focal range formed within the range of ±10% (16.2 to 19.8 nm) of the size of 18 nm in the LS pattern was obtained. The larger the value, the wider the focal depth.

[0830] [Evaluation of the collapse limit of line patterns]

[0831] The line size of each exposure amount in the optimal focus of the LS pattern was measured at 10 locations in the long-side direction. The thinnest line size that can be obtained without collapse is taken as the collapse limit size. The smaller the value, the better the collapse limit.

[0832] [Table 3]

[0833]

[0834]

[0835] [Table 4]

[0836]

[0837] From the results shown in Tables 3 and 4, it was confirmed that the chemically amplified resist composition of the present invention has good sensitivity, is excellent in various lithography properties, and exhibits strong resistance to pattern collapse.

[0838] [5]EUV lithography evaluation (2)

[0839] [Examples 4-1 to 4-20, Comparative Examples 3-1 to 3-16]

[0840] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-16) was spin-coated on a Si substrate on which a silicon-containing spin-coated hard mask SHB-A940 (containing 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and pre-baked using a hot plate at 100° C. for 60 seconds to produce a resist film with a film thickness of 60 nm. Then, the above-mentioned resist film was exposed using an EUV scanning exposure machine NXE3400 manufactured by ASML (NA0.33, σ0.9 / 0.6, quadrupole illumination, a mask of a hole pattern with a size pitch of 44nm on the wafer and a deviation of +20%), and PEB was performed for 60 seconds on a heating plate at the temperature described in Tables 5 and 6, and development was performed for 30 seconds with a 2.38 mass% TMAH aqueous solution. In Examples 4-1 to 4-18 and Comparative Examples 3-1 to 3-10, a hole pattern with a size of 22nm was obtained, and in Examples 4-19, 4-20 and Comparative Examples 3-11, 3-12, a dot pattern with a size of 22nm was obtained.

[0841] The exposure amount when a hole or dot size of 22 nm was formed was measured using CD-SEM (CG6300) manufactured by Hitachi Advanced Technology Co., Ltd., and the result was defined as sensitivity. The size of 50 holes or dots at this time was measured, and the value (3σ) three times the standard deviation (σ) calculated from the result was defined as CDU. The results are shown in Tables 5 and 6.

[0842] [Table 5]

[0843]

[0844] [Table 6]

[0845]

[0846] From the results shown in Tables 5 and 6, it was confirmed that the chemically amplified resist composition including the photoacid generator / quencher composed of the onium salt of the present invention had good sensitivity and excellent CDU.

Claims

1. An onium salt represented by the following formula (1); Wherein, n1 is an integer from 0 to 6; n2 is 1 or 2; W is an aliphatic heterocyclic ring having 2 to 20 carbon atoms and containing a nitrogen atom which may also contain a heteroatom; L A and L B each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond or a carbamate bond; X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom; R 1 is a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms; when n1≥2, multiple R 1 They may also be bonded to each other and to form a ring together with the carbon atom on W to which they are bonded; R 2 and R 3 are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; and R 2 and R 3 They may also bond to each other and form a ring together with the carbon atoms to which they are bonded; Q 1 and Q 2 Each independently represents a hydrogen atom, a fluorine atom, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms; but Q 1 and Q 2 At least one of them is a fluorine atom or a fluorinated hydrocarbon group having 1 to 6 carbon atoms; R AL It is an acid-labile group; Z + It is an onium cation.

2. The onium salt according to claim 1, wherein R AL A group represented by the following formula (AL-1) or (AL-2); Where, L C is -O- or -S-; R 4 , R 5 and R 6 are each independently a hydrocarbon group having 1 to 10 carbon atoms; and R 4 , R 5 and R 6 Any two of them may also be bonded to each other to form a ring together with the carbon atoms to which they are bonded; R 7 and R 8 Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; R 9 is a hydrocarbon group having 1 to 20 carbon atoms, wherein -CH2- in the hydrocarbon group may be substituted by -O- or -S-; and R 8 and R 9 They can also bond to each other and to the carbon atoms and L C Together they form a heterocyclic group having 3 to 20 carbon atoms, wherein -CH2- in the heterocyclic group may be substituted by -O- or -S-; m1 and m2 are each independently 0 or 1; * indicates an atomic bond to an adjacent -O- atom.

3. The onium salt according to claim 1, wherein Z + It is a sulfonium cation represented by the following formula (cation-1), an iodonium cation represented by the following formula (cation-2), or an ammonium cation represented by the following formula (cation-3); In the formula, R c1 ~R c9 are each independently a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom; and R c1 and R c2 They may also bond to each other to form a ring together with the sulfur atom to which they are bonded.

4. The onium salt according to claim 1, represented by the following formula (1A); Where n1, n2, W, L A , X L , R 1 ~R 3 , Q 1 , Q 2 , R AL and Z + Same as above.

5. The onium salt according to claim 4, represented by the following formula (1B); Where n1, W, L A , X L , R 1 ~R 3 , R AL and Z + Same as above. 6 . A photoacid generator and quencher, comprising the onium salt according to claim 1 .

7. A chemically amplified resist composition comprising the photoacid generator-cum-quencher according to claim 6.

8. The chemically amplified resist composition according to claim 7, further comprising an organic solvent.

9. The chemically amplified resist composition according to claim 7, comprising a base polymer containing a repeating unit represented by the following formula (a1); In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X 1 is a single bond, phenylene, naphthylene or *-C(=O)-OX 11 -, the phenylene or naphthylene group may be substituted by an alkoxy group having 1 to 10 carbon atoms which may also contain a fluorine atom or a halogen atom; X 11 It is a saturated alkylene group, phenylene group or naphthylene group having 1 to 10 carbon atoms. The saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. * represents an atomic bond to a carbon atom of the main chain; AL 1 It is an acid-labile group.

10. The chemically amplified resist composition according to claim 9, wherein The base polymer further comprises a repeating unit represented by the following formula (a2); In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; X 2 is a single bond or *-C(=O)-O-; * represents an atomic bond to a carbon atom of the main chain; R 11 is a halogen atom, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom; AL 2 It is an acid-labile group; a is an integer from 0 to 4.

11. The chemically amplified resist composition according to claim 9, wherein: The base polymer further comprises a repeating unit represented by the following formula (b1) or (b2); In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; Y 1 is a single bond or *-C(=O)-O-; * represents an atomic bond to a carbon atom of the main chain; R 21 A group having 1 to 20 carbon atoms and a structure containing at least one selected from the group consisting of 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 sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-); R 22 is a halogen atom, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom; b is an integer from 1 to 4; c is an integer from 0 to 4; but 1≤b+c≤5.

12. The chemically amplified resist composition according to claim 9, wherein: The base polymer further comprises a repeating unit represented by any of the following formulae (c1) to (c4); In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; Z 1 is a single bond or a phenylene group; Z 2 **-C(=O)-OZ 21 -, **-C(=O)-NH-Z 21 -or**-OZ 21 -;Z 21 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group; Z 3 Each is independently a single bond, phenylene, naphthylene or *-C(=O)-OZ 31 -;Z 31 is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring; Z 4 Each is independently a single bond, ***-Z 41 -C(=O)-O-、***-C(=O)-NH-Z 41 -or***-OZ 41 -;Z 41 is an alkylene group having 1 to 20 carbon atoms which may contain heteroatoms; Z 5 Each is independently a single bond, ****-Z 51 -C(=O)-O-、****-C(=O)-NH-Z 51 -or****-OZ 51 -;Z 51 is an alkylene group having 1 to 20 carbon atoms which may contain heteroatoms; Z 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, *-C(=O)-OZ 61 -, *-C(=O)-N(H)-Z 61 -or*-OZ 61 -;Z 61 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group; * indicates an atomic bond to a carbon atom in the main chain; ** indicates an atomic bond to Z 1 *** indicates atomic bond with Z 3 Atomic bonds with Z 4 Atomic bonds; R 31 and R 32 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom; and R 31 and R 32 They may also bond to each other and form a ring together with the sulfur atom to which they are bonded; L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond; R 1 and Rf 2 Each is independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; R 3 and Rf 4 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; R 5 and Rf 6 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; however, all Rf 5 and Rf 6 Not all hydrogen atoms at the same time; M - It is a non-nucleophilic counter ion; A + is an onium cation; d is an integer from 0 to 3.

13. The chemically amplified resist composition according to claim 7, further comprising a photoacid generator.

14. The chemically amplified resist composition according to claim 7, further comprising a quencher.

15. The chemically amplified resist composition according to claim 7, further comprising a surfactant.

16. A method for forming a pattern, comprising the following steps: A resist film is formed on a substrate using the chemically amplified resist composition according to claim 7; the resist film is exposed to high-energy rays; and the exposed resist film is developed using a developer.

17. The pattern forming method according to claim 16, wherein: The high-energy ray is KrF excimer laser, ArF excimer laser, electron beam or extreme ultraviolet ray with a wavelength of 3 to 15 nm.

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