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

Abstract

The invention relates to an onium salt type monomer, a polymer, a chemically amplified resist composition and a pattern forming method. The present invention provides a photolithographic composition which has excellent solvent solubility in lithography using high-energy rays, and excellent lithography performance such as high sensitivity, high contrast, exposure margin, edge roughness, size uniformity, and focal depth, and which can be used in lithography using high-energy rays. The present invention relates to an onium salt-type monomer used in a chemically amplified resist composition which has excellent etching resistance and pattern collapse resistance even in fine pattern formation, a polymer comprising a repeating unit derived from the onium salt-type monomer, a chemically amplified resist composition comprising the polymer, and a method for producing the chemically amplified resist composition. And a pattern forming method using the chemically amplified resist composition. An onium salt type monomer comprising an anion represented by formula (a1) and a cation represented by formula (a2). # imgabs0 #

Description

Technical Field

[0001] The present invention relates to an onium salt monomer, a polymer, a chemically amplified resist composition, and a patterning method. Background Art

[0002] With the high integration and high speed of LSIs, the miniaturization of pattern rules has been rapidly progressing. In particular, the market expansion of flash memories and the increase in memory capacity have promoted miniaturization. As the most advanced miniaturization technology, mass production of 65 nm node devices is being carried out by ArF lithography, and preparations for mass production of 45 nm node devices by the next-generation ArF immersion lithography are underway. As the next-generation 32 nm node devices, immersion lithography using an ultra-high NA lens that combines a liquid having a refractive index higher than that of water, a high refractive index lens, and a high refractive index resist film, extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm, double exposure (double patterning lithography) of ArF lithography, etc. are candidates and are being studied.

[0003] With the progress of miniaturization, as the light approaches the diffraction limit, the contrast of light decreases. Due to the decrease in the contrast of light, the resolution and focus tolerance of hole patterns and trench patterns are reduced in a positive resist film.

[0004] With the miniaturization of patterns, the edge roughness (LWR) of line patterns and the critical dimension uniformity (CDU) of hole patterns are also regarded as problems. The effects of non-uniform distribution and aggregation of the base polymer and the acid generator, and the effect of acid diffusion have been pointed out. Furthermore, as the resist film becomes thinner, the LWR tends to increase, and the deterioration of the LWR due to the thinning accompanying the progress of miniaturization has become a serious problem.

[0005] In a resist composition for EUV lithography, it is necessary to simultaneously achieve high sensitivity, high resolution, and low LWR. If the acid diffusion distance is shortened, the LWR becomes smaller, but the sensitivity decreases. For example, by lowering the post-exposure bake (PEB) temperature, the LWR becomes smaller, but the sensitivity decreases. Even if the amount of quencher added is increased, the LWR becomes smaller, but the sensitivity decreases. It is necessary to break the trade-off relationship between sensitivity and LWR.

[0006] In order to suppress the diffusion of acid, a resist compound having a repeating unit of an onium salt of a sulfonic acid having a polymerizable unsaturated group has been proposed (Patent Document 1). This so-called polymer-bound acid generator has a very short acid diffusion characteristic because it generates a polymeric sulfonic acid by exposure. In addition, by increasing the ratio of the acid generator, the sensitivity can also be improved. In the case of an additive acid generator, if the addition amount is increased, the sensitivity is increased, but in this case, the acid diffusion distance also increases. Since the acid diffuses unevenly, when the acid diffusion increases, the LWR and CDU deteriorate. In terms of the balance of sensitivity, LWR, and CDU, it can be said that the polymeric acid generator has high performance.

[0007] Since the iodine atom has a very large absorption of EUV at a wavelength of 13.5 nm, the effect of generating secondary electrons from the iodine atom during exposure has been confirmed and is highly regarded in EUV lithography. Patent Document 2 describes a photoacid generator in which an iodine atom is introduced into an anion, and Patent Document 3 describes a photoacid generator having a polymerizable group in which an iodine atom is introduced into an anion. Patent Document 4 describes a photoacid generator in which an iodine atom is introduced into both a cation and an anion. By this, although a certain degree of improvement in lithography performance has been confirmed, the solubility of the iodine atom in an organic solvent is not high, and there is a concern about precipitation in the solvent.

[0008] Patent Document 5 describes a photoacid generator in which a plurality of fluorine atoms are introduced into a cation. Although the solubility of the photoacid generator in a solvent has been improved by the introduction of a plurality of fluorine atoms, it is not sufficient from the viewpoint of EUV absorption, and there is room for improvement.

[0009] Patent Documents 6 to 10 describe photoacid generators and quenchers (acid diffusion control agents) containing iodine atoms and fluorine atoms in a cation. Patent Document 11 describes an onium salt monomer in which an iodine atom and a polymerizable group are introduced into a cation. Through these developments, an improvement in the performance as a resist material has been confirmed, but it is still not satisfactory from the viewpoint of acid diffusion control, and the development of a resist material useful for further fine pattern formation is required.

[0010] [Prior Art Documents]

[0011] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent No. 4425776 Gazette

[0013] [Patent Document 2] Japanese Patent No. 6720926 Gazette

[0014] [Patent Document 3] Japanese Patent No. 6973274 Gazette

[0015] [Patent Document 4] Japanese Patent No. 7041204 Gazette

[0016] [Patent Document 5] Japanese Patent Publication No. 7389562

[0017] [Patent Document 6] Japanese Unexamined Patent Application Publication No. 2021-123579

[0018] [Patent Document 7] Japanese Unexamined Patent Application Publication No. 2021-123580

[0019] [Patent Document 8] Japanese Unexamined Patent Application Publication No. 2022-123839

[0020] [Patent Document 9] Japanese Unexamined Patent Application Publication No. 2023-88869

[0021] [Patent Document 10] Japanese Unexamined Patent Application Publication No. 2023-88870

[0022] [Patent Document 11] Japanese Unexamined Patent Application Publication No. 2022-28615 SUMMARY OF THE INVENTION

[0023] [Problems to be Solved by the Invention]

[0024] In a chemically amplified resist composition using an acid as a catalyst, it is desired to develop a resist composition having higher sensitivity, capable of improving the LWR of line patterns and the CDU of hole patterns, and also having excellent etching resistance after pattern formation.

[0025] The present invention has been made in view of the above circumstances, and an object thereof is to provide an onium salt type monomer, a polymer containing a repeating unit derived from the onium salt type monomer, a chemically amplified resist composition containing the polymer, and a pattern forming method using the chemically amplified resist composition. The onium salt type monomer is used in a chemically amplified resist composition that has excellent solvent solubility, high sensitivity, high contrast, excellent lithography performance such as exposure latitude (EL), LWR, CDU, and depth of focus (DOF) in lithography using high-energy rays such as KrF excimer laser, ArF excimer laser, electron beam (EB), and EUV, and is not likely to cause pattern collapse in the formation of fine patterns and also has excellent etching resistance.

[0026] [Means for Solving the Problems]

[0027] The present inventors have conducted intensive studies to achieve the aforementioned objectives and have discovered that a polymer comprising repeating units derived from an onium salt-type monomer having good solvent solubility, wherein the onium salt-type monomer comprises a fluorosulfonium anion comprising a polymerizable group and an aromatic ring structure substituted with an iodine atom, and a triarylsulfonium cation comprising an iodine atom and a fluorine atom, and that by using this polymer as a polymer-bound photoacid generator, a chemically amplified resist composition can be obtained that exhibits high sensitivity, high contrast, high resolution, improved lithographic performance such as LWR and CDU, and excellent etching resistance after patterning. This has led to the completion of the present invention.

[0028] That is, the present invention provides the following onium salt-type monomers, polymers, chemically amplified resist compositions, and pattern formation methods.

[0029] 1. An onium salt-type monomer, consisting of an anion represented by the following formula (a1) and a cation represented by the following formula (a2),

[0030] [Chemistry 1]

[0031]

[0032] In the formula, n1 is 0 or 1, n2 is 0 or 1, n3 is an integer of 0 to 4, n4 is an integer of 0 to 4, n5 is an integer of 1 to 6, but when n2 is 0, 1≤n4+n5≤4, when n2 is 1, 1≤n4+n5≤6, n6 is an integer of 0 to 4, n7 is 0 or 1, n8 is 0 or 1, but n7 and n8 are not both 0.

[0033] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0034] R 1 is a halogen, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain heteroatoms, or a hydrocarbonthio group having 1 to 20 carbon atoms which may contain heteroatoms. When n3 is 2, 3 or 4 and n7 is 1, each R 1 They can be the same or different. 1 can be bonded to each other and to the carbon atoms to which they are bonded to form a ring, when n8 is 0, n7 is 1 and n3 is 1, 2, 3 or 4, and at least one R 1 is an iodine atom,

[0035] R 2 is a halogen atom other than an iodine 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, or a hydrocarbonthio group having 1 to 20 carbon atoms which may contain a hetero atom; when n4 is 2, 3 or 4 and n8 is 1, each R 2 They can be the same or different. 2They can be bonded to each other and together with the carbon atoms to which they are bonded form a ring.

[0036] L A1 、L B1 and L C are each independently a single bond, an ether bond, an ester bond, a sulfonate bond, an amide bond, a sulfonamide bond, a carbonate bond or a carbamate bond.

[0037] X L1 is a single bond or an alkylene group having 1 to 40 carbon atoms which may also contain heteroatoms.

[0038] Q 1 and Q 2 are each independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0039] Q 3 and Q 4 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0040] [Chemical formula 2]

[0041]

[0042] In the formula, m1 is 0 or 1, m2 is 0 or 1, m3 is 0 or 1, m4 is an integer from 0 to 4, m5 is an integer from 0 to 4, m6 is an integer from 0 to 6, m7 is an integer from 0 to 6, m8 is an integer from 0 to 2, m9 is an integer from 0 to 2, m10 is an integer from 0 to 2, m11 is 0 or 1, m12 is an integer from 0 to 4, m13 is an integer from 0 to 2, m14 is an integer from 0 to 2. However, when m1 is 0, 0 ≤ m6 + m9 ≤ 4; when m1 is 1, 0 ≤ m6 + m9 ≤ 6; when m2 is 0, 0 ≤ m7 + m10 ≤ 4; when m2 is 1, 0 ≤ m7 + m10 ≤ 6; when m3 is 0, 1 ≤ m4 + m5 + m8 + m14 ≤ 4; when m3 is 1, 1 ≤ m4 + m5 + m8 + m14 ≤ 6; when m11 is 0, 0 ≤ m12 + m13 ≤ 4; when m11 is 1, 0 ≤ m12 + m13 ≤ 6. Also, m4 + m12 ≥ 1.

[0043] R F1 ~R F3 are each independently a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxy group having 1 to 6 carbon atoms or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms. When m6 is 2 or more, each R F 1 can be the same or different from each other. When m7 is 2 or more, each R F2 can be the same or different from each other. When m5 is 2 or more, each R F3 can be the same or different from each other.

[0044] R3 ~R 6 is a halogen atom other than an iodine atom and a fluorine atom, a nitro group, a nitrile group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbon thio group having 1 to 20 carbon atoms which may contain a hetero atom. When m8 is 2, two Rs 3 may be the same or different from each other, and the two Rs 3 may be bonded to each other and form a ring together with the carbon atom to which they are bonded. When m9 is 2, two Rs 4 may be the same or different from each other, and the two Rs 4 may be bonded to each other and form a ring together with the carbon atom to which they are bonded. When m10 is 2, two Rs 5 may be the same or different from each other, and the two Rs 5 may be bonded to each other and form a ring together with the carbon atom to which they are bonded. When m13 is 2, two Rs 6 may be the same or different from each other, and the two Rs 6 may be bonded to each other and form a ring together with the carbon atom to which they are bonded.

[0045] In addition, the aromatic rings directly bonded to the sulfur cation may be bonded to each other and form a ring together with S + +

[0046] L A2 and L B2 are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond.

[0047] X L2 is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom.

[0048] 2. The onium salt type monomer according to 1., wherein the anion is represented by the following formula (a1-1)

[0049] [Chemical formula 3]

[0050]

[0051] In the formula, n1 to n6, R A , R 1 , R 2 , L A1 , L C and Q 1 ~Q 4 are the same as those described above.

[0052] 3. The onium salt type monomer according to 2., wherein the anion is represented by the following formula (a1-2):

[0053] [Formula 4]​​

[0054]

[0055] In the formula, n1 to n6, R A , R 1 , R 2 , L A1 and Q 1 to Q 4 are the same as those described above.

[0056] 4. An onium salt type monomer according to any one of 1. to 3., wherein the cation is represented by the following formula (a2-1),

[0057] [Chemical formula 5]

[0058]

[0059] In the formula, m4 to m10, m12 to m14, R F1 to R F3 , R 3 to R 6 , L A2 , L B2 and X L2 are the same as those described above.

[0060] 5. An onium salt type monomer according to 4., wherein the cation is represented by the following formula (a2-2),

[0061] [Chemical formula 6]

[0062]

[0063] In the formula, m4 to m10, R F 1 to R F3 and R 3 to R 5 are the same as those described above.

[0064] 6. A monomeric photoacid generator comprising an onium salt type monomer according to any one of 1. to 5.

[0065] 7. A polymer comprising repeating units derived from the monomeric photoacid generator according to 6.

[0066] 8. The polymer according to 7., further comprising repeating units represented by the following formula (b1) or (b2),

[0067] [Chemical formula 7]

[0068]

[0069] In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0070] X 1 represents a single bond, phenylene, naphthylene, *-C(=O)-O-X 11 - or *-C(=O)-NH-X 11 -, and the phenylene or naphthylene may be substituted by a hydroxyl group, nitro group, cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom, and X 11 is a saturated alkylene group having 1 to 10 carbon atoms, phenylene or naphthylene, and the saturated alkylene group may contain a hydroxyl group, ether bond, ester bond or lactone ring,

[0071] X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-,

[0072] * represents an atomic bond with the carbon atom of the main chain,

[0073] R 11 is a halogen atom, cyano group, hydroxyl group, nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom,

[0074] AL 1 and AL 2 are each independently an acid-labile group,

[0075] a is an integer of 0 to 4.

[0076] 9. The polymer according to 7. or 8., further comprising a repeating unit represented by the following formula (b3),

[0077] [Chemical formula 8]

[0078]

[0079] In the formula, b1 is 0 or 1, b2 is an integer of 0 to 3 when b1 is 0, and an integer of 0 to 5 when b1 is 1,

[0080] R A is a hydrogen atom, fluorine atom, methyl group or trifluoromethyl group,

[0081] X 3 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, and * represents an atomic bond with the carbon atom of the main chain,

[0082] R 12 and R 13 are each independently a hydrogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. Additionally, R12 and R 13 may be bonded to each other and together with the carbon atoms to which they are bonded form a ring,

[0083] R 14 represents a halogen atom, a hydroxyl group, a cyano group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon thio group having 1 to 20 carbon atoms which may contain a hetero atom, or -N(R 14A )(R 14B ), R 14A and R 14B are each independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. When b2 is 2 or more, a plurality of R 14 may be bonded to each other and together with the carbon atoms of the aromatic ring to which they are bonded form a ring,

[0084] X 4 is a single bond, an aliphatic alkylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining them,

[0085] X 5 and X 6 are each independently an oxygen atom or a sulfur atom, provided that X 4 and X 6 are bonded to adjacent carbon atoms of the aromatic ring.

[0086] 10. The polymer according to any one of 7. to 9., further comprising a repeating unit represented by the following formula (c1),

[0087] [Chemical formula 9]

[0088]

[0089] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group,

[0090] Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * represents a bond to a carbon atom of the main chain,

[0091] R 21 is a halogen atom, a nitro group, a cyano group, a carboxyl group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom,

[0092] c is an integer from 1 to 4, and d is an integer from 0 to 3, provided that 1 ≤ c + d ≤ 5.

[0093] 11. The polymer according to any one of 7. to 10. further comprises a repeating unit represented by the following formula (d1):

[0094] [Chemical formula 10]

[0095]

[0096] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0097] Z 1 represents a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-Z 11 -, or *-C(=O)-NH-Z 11 -, the phenylene group or naphthylene group may be substituted with a hydroxyl group, a nitro group, a cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom, * represents an atomic bond with a carbon atom of the main chain, Z 11 is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring,

[0098] R 31 is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one or more structures selected from hydroxyl groups other than phenolic hydroxyl groups, cyano groups, carbonyl groups, carboxyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings and carboxylic anhydrides (-C(=O)-O-C(=O)-).

[0099] 12. A chemically amplified resist composition comprising (A) a base polymer containing the polymer according to any one of 7. to 11.

[0100] 13. The chemically amplified resist composition according to 12. further comprises (B) an organic solvent.

[0101] 14. The chemically amplified resist composition according to 12. or 13. further comprises (C) a quencher.

[0102] 15. The chemically amplified resist composition according to any one of 12. to 14. further comprises (D) an acid generator.

[0103] 16. The chemically amplified resist composition according to any one of 12. to 15. further comprises (E) a surfactant.

[0104] 17. The chemically amplified resist composition according to any one of 12. to 16. further comprises (F) a dissolution inhibitor.

[0105] 18. A pattern forming method comprising the following steps:

[0106] Form a resist film on a substrate using a chemically amplified resist composition according to any one of 12. to 17.;

[0107] Expose the resist film to high-energy rays; and,

[0108] Develop the exposed resist film using a developer.

[0109] 19. The pattern forming method according to 18., wherein the high-energy ray is an ArF excimer laser having a wavelength of 193 nm, a KrF excimer laser having a wavelength of 248 nm, an electron beam, or extreme ultraviolet rays having a wavelength of 3 to 15 nm.

[0110] [Effects of the Invention]

[0111] A polymer containing a repeating unit derived from an onium salt type monomer and generating an acid upon exposure has good solubility due to the increased lipophilicity caused by fluorine atoms. The onium salt type monomer is composed of a fluoroalkylsulfonate anion containing a polymerizable group and an aromatic ring structure substituted with an iodine atom, and a triarylsulfonium cation containing an iodine atom and a fluorine atom. The triarylsulfonium cation containing an iodine atom and a fluorine atom, especially in EUV lithography with a wavelength of 13.5 nm, has a very large absorption of EUV caused by the iodine atom, so secondary electrons are generated from the iodine atom during exposure. In addition, due to the electron-withdrawing effect caused by the fluorine atom, the energy level of the lowest unoccupied molecular orbital (LUMO) in the frontier orbital theory is lowered, making it easy to accept the generated secondary electrons, thus promoting the decomposition of the cation and effectively generating an acid. On the other hand, in the fluoroalkylsulfonate anion containing a polymerizable group and an aromatic ring structure substituted with an iodine atom, since the anion also has an iodine atom, secondary electrons are generated, promoting the decomposition of the cation, and being highly sensitized by these synergistic effects. In addition, due to the large atomic weight of the fluorine atom and the structure in which the generated acid bonds to the polymer main chain, it has the characteristic of small acid diffusion. Thus, it is possible to prevent the reduction in resolution caused by the blur of acid diffusion, and to improve LWR and CDU. In addition, the aromatic ring in the repeating unit functions as a good etching-resistant group, which is ideal in fine pattern formation. Detailed Description

[0112] [Onium Salt Type Monomer]

[0113] The onium salt type monomer of the present invention contains an anion represented by the following formula (a1).

[0114] [Chemical Formula 11]

[0115]

[0116] In formula (a1), n1 is 0 or 1. When n1 is 0, it is a benzene ring, and when n1 is 1, it is a naphthalene ring. However, from the viewpoint of solvent solubility, a benzene ring with n1 = 0 is preferred. n2 is 0 or 1. When n2 is 0, it is a benzene ring, and when n2 is 1, it is a naphthalene ring. However, from the viewpoint of solvent solubility, a benzene ring with n2 = 0 is preferred.

[0117] In formula (a1), n3 is an integer from 0 to 4. From the viewpoint of raw material supply, n3 is preferably 0, 1, or 2, more preferably 0 or 1. n4 is an integer from 0 to 4, more preferably 0, 1, or 2, and even more preferably 0 or 1.

[0118] In formula (a1), n5 is an integer from 1 to 6. The more iodine atoms in the anion structure, especially the higher the absorption of EUV, but there may be a concern of insufficient solvent solubility and precipitation in the resist composition. Therefore, n5 is preferably 1, 2, or 3, more preferably 1 or 2. However, when n2 = 0, 1 ≤ n4 + n5 ≤ 4, and when n2 = 1, 1 ≤ n4 + n5 ≤ 6.

[0119] In formula (a1), n6 is an integer from 0 to 4, preferably 0, 1, 2, or 3, more preferably 1. n7 is 0 or 1. n8 is 0 or 1. However, n7 and n8 are not both 0 at the same time.

[0120] In formula (a1), R A is preferably a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among them, a hydrogen atom and a methyl group are preferred, and a hydrogen atom is more preferred.

[0121] In formula (a1), the iodine atom in the aromatic ring of the anion is preferably bonded to the ortho position of the carbon atom to which L B1 is bonded. Since the iodine atom is an element with a large atomic radius, the rotation of the bonding axes of the aromatic ring to which the polymerizable group is bonded and the aromatic ring to which the iodine atom is bonded is inhibited, and the rigidity of the polymer is increased.

[0122] In formula (a1), R 1is a halogen, nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may also contain heteroatoms, a hydrocarbon oxy group having 1 to 20 carbon atoms which may also contain heteroatoms, or a hydrocarbon thio group having 1 to 20 carbon atoms which may also contain heteroatoms. As the above-mentioned halogen, a fluorine atom, a chlorine atom, a bromine atom or an iodine atom is preferable, and a fluorine atom or an iodine atom is more preferable. The hydrocarbon group portion of the aforementioned hydrocarbon group, hydrocarbon oxy group and hydrocarbon thio group may be saturated or unsaturated, and may be linear, branched or cyclic. As specific examples thereof, alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl butyl, tert-butyl-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, etc.; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl, etc.; alkenyl groups having 2 to 20 carbon atoms such as vinyl, propenyl, butenyl, hexenyl, etc.; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclohexenyl, etc.; aryl groups having 6 to 20 carbon atoms such as phenyl, naphthyl, etc.; aralkyl groups having 7 to 20 carbon atoms such as benzyl, 1-phenylethyl, 2-phenylethyl, etc.; groups obtained by combining them, etc. In addition, a part or all of the hydrogen atoms of the above-mentioned hydrocarbon group may be substituted with a group containing heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- of the above-mentioned hydrocarbon group may be substituted with a group containing heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. 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)-O-C(=O)-), a haloalkyl group, etc. When n3 is 2, 3 or 4 and n7 is 1, each R 1 may be the same as or different from each other.

[0123] In addition, when n3 is 2, 3 or 4 and n7 is 1, a plurality of R 1 may be bonded to each other and together with the carbon atoms of the aromatic ring to which they are bonded, form a ring. As specific examples of the ring formed at this time, a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. may be mentioned. In addition, a part or all of the hydrogen atoms in the above-mentioned ring may be substituted with a group containing heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- in the above-mentioned ring may be substituted with a group containing heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. As a result, 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)-O-C(=O)-), a haloalkyl group, etc. However, when n8 is 0, n7 is 1 and n3 is 1, 2, 3 or 4, and at least one R 1 is an iodine atom.

[0124] In formula (a1), R 2 is a halogen atom other than an iodine atom, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbon thio group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of the halogen atom other than the iodine atom include a fluorine atom, a chlorine atom, a bromine atom, etc. The hydrocarbon group portion of the aforementioned hydrocarbon group, hydrocarbon oxy group, and hydrocarbon thio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same examples as those exemplified for the hydrocarbon group represented by R 1 , but are not limited thereto. When n4 is 2, 3, or 4 and n8 is 1, each R 2 may be the same or different from each other.

[0125] In addition, when n4 is 2, 3, or 4 and n8 is 1, a plurality of R 2 may be bonded to each other and together with the carbon atom to which they are bonded, form a ring. As the above ring, a 5- to 8-membered ring is preferred.

[0126] In formula (a1), L A1 , L B1 and L C are each independently a single bond, an ether bond, an ester bond, a sulfonate bond, an amide bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. Among them, L A1 , as the ester bond, is preferably a single bond, an ether bond, an ester bond, or a sulfonate bond, more preferably an ester bond or a sulfonate bond. L B1 is preferably a single bond, an ether bond, or an ester bond, more preferably a single bond. L C is preferably a single bond, an ether bond, an ester bond, or a sulfonate bond, more preferably an ether bond or an ester bond.

[0127] In formula (a1), X L1 is a single bond, or an alkylene group having 1 to 40 carbon atoms which may contain a heteroatom. The aforementioned alkylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl, cyclic saturated alkylene group, arylene group, etc. Specific examples of the above heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, etc.

[0128] X L1 The specific examples of the alkylene group having 1 to 40 carbon atoms which may contain a heteroatom represented by may be listed as follows, but are not limited to these. It should be noted that in the following formula, * respectively represents the atomic bond with L A1 and with L B1 .

[0129] [Chemical formula 12]

[0130]

[0131] [Chemical formula 13]

[0132]

[0133] [Chemical Formula 14]

[0134]

[0135] [Chemical Formula 15]

[0136]

[0137] Among them, X L -0 to X L -22, X L -29 to X L -34 and X L -47 to X L -58 is preferred.

[0138] In formula (a1), Q 1 and Q 2 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms is preferably trifluoromethyl.

[0139] In formula (a1), Q 3 and Q 4 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Each independently being a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms is preferably trifluoromethyl. Q 3 and Q 4 are more preferably fluorine atoms.

[0140] In formula (a1), -[C(Q 1 )(Q 2 )] n6 -C(Q 3 )(Q 4 )-SO3 - Specific examples of the partial structure represented by are preferably those shown below, but are not limited to these. It should be noted that in the following formula, * represents the atomic bond with L C of.

[0141] [Chemical Formula 16]

[0142]

[0143] Among these, Acid-1 to Acid-7 are preferred, and Acid-1 to Acid-3, Acid-6, and Acid-7 are more preferred.

[0144] As the anion represented by formula (a1), the anion represented by the following formula (a1-1) is preferred.

[0145] [Chemical formula 17]

[0146]

[0147] In the formula, n1 to n6, R A , R 1 , R 2 , L A1 , L C and Q 1 to Q 4 are the same as those described above.

[0148] As the anion structure represented by formula (a1-1), the anion structure represented by the following formula (a1-2) is preferred.

[0149] [Chemical formula 18]

[0150]

[0151] In the formula, n1 to n6, R A , R 1 , R 2 , L A1 and Q 1 to Q 4 are the same as those described above.

[0152] As the anion represented by formula (a1), the following anions can be cited, but are not limited to these. It should be noted that in the following formula, R A , Q 1 , R 2 , n, and n are the same as those described above, and Me is a methyl group. In addition, the bonding positions of various substituents on the aromatic ring can be interchanged with each other.

[0153] [Chemical formula 19]

[0154]

[0155] [Chemical formula 20]

[0156]

[0157] [Chemical formula 21]

[0158]

[0159] [Chemical formula 22]

[0160]

[0161] [Chemical formula 23]

[0162]

[0163] [Chemical formula 24]

[0164]

[0165] [Chemical formula 25]

[0166]

[0167] [Chemical formula 26]

[0168]

[0169] [Chemical formula 27]

[0170]

[0171] [Chemical formula 28]

[0172]

[0173] [Chemical formula 29]

[0174]

[0175] [Chemical formula 30]

[0176]

[0177] [Chemical formula 31]

[0178]

[0179] [Chemical formula 32]

[0180]

[0181] [Chemical formula 33]

[0182]

[0183] [Chemical formula 34]

[0184]

[0185] [Chemical formula 35]

[0186]

[0187] [Chemical formula 36]

[0188]

[0189] [Chemical formula 37]

[0190]

[0191] [Chemical formula 38]

[0192]

[0193] [Chemical Formula 39]

[0194]

[0195] [Chemical Formula 40]

[0196]

[0197] [Chemical Formula 41]

[0198]

[0199] [Chemical Formula 42]

[0200]

[0201] [Chemical Formula 43]

[0202]

[0203] [Chemical Formula 44]

[0204]

[0205] [Chemical Formula 45]

[0206]

[0207] [Chemical Formula 46]

[0208]

[0209] [Chemical Formula 47]

[0210]

[0211] [Chemical Formula 48]

[0212]

[0213] [Chemical Formula 49]

[0214]

[0215] [Chemical Formula 50]

[0216]

[0217] [Chemical Formula 51]

[0218]

[0219] [Chemical Formula 52]

[0220]

[0221] [Chemical Formula 53]

[0222]

[0223] [Chemical Formula 54]

[0224]

[0225] [Chemical Formula 55]

[0226]

[0227] [Chemical Formula 56]

[0228]

[0229] [Chemical Formula 57]

[0230]

[0231] [Chemical Formula 58]

[0232]

[0233] [Chemical Formula 59]

[0234]

[0235] [Chemical Formula 60]

[0236]

[0237] [Chemical Formula 61]

[0238]

[0239] [Chemical Formula 62]

[0240]

[0241] [Chemical Formula 63]

[0242]

[0243] [Chemical Formula 64]

[0244]

[0245] [Chemical Formula 65]

[0246]

[0247] [Chemical Formula 66]

[0248]

[0249] [Chemistry 67]

[0250]

[0251] [Chemistry 68]

[0252]

[0253] [Chemistry 69]

[0254]

[0255] [Chemistry 70]

[0256]

[0257] [Chemistry 71]

[0258]

[0259] [Chemistry 72]

[0260]

[0261] [Chemistry 73]

[0262]

[0263] [Chemistry 74]

[0264]

[0265] [Chemistry 75]

[0266]

[0267] [Chemistry 76]

[0268]

[0269] [Chemistry 77]

[0270]

[0271] [Chemistry 78]

[0272]

[0273] [Chemistry 79]

[0274]

[0275] [Chemistry 80]

[0276]

[0277] [Chemical Formula 81]

[0278]

[0279] [Chemical Formula 82]

[0280]

[0281] [Chemical Formula 83]

[0282]

[0283] [Chemical Formula 84]

[0284]

[0285] [Chemical Formula 85]

[0286]

[0287] [Chemical Formula 86]

[0288]

[0289] [Chemical Formula 87]

[0290]

[0291] [Chemical Formula 88]

[0292]

[0293] [Chemical Formula 89]

[0294]

[0295] [Chemical Formula 90]

[0296]

[0297] [Chemical Formula 91]

[0298]

[0299] [Chemical Formula 92]

[0300]

[0301] [Chemical Formula 93]

[0302]

[0303] [Chemical Formula 94]

[0304]

[0305] As an example of other anions, the anions described in paragraphs

[0023] to

[0029] of Japanese Patent No. 6973274 can also be cited.

[0306] The onium salt monomer of the present invention contains a cation represented by the following formula (a2).

[0307] [Chemical formula 95]

[0308]

[0309] In formula (a2), m1 is 0 or 1. When m1 is 0, it is a benzene ring, and when m1 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with m1 being 0 is preferred. m2 is 0 or 1. When m2 is 0, it is a benzene ring, and when m2 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with m2 being 0 is preferred. m3 is 0 or 1. When m3 is 0, it is a benzene ring, and when m3 is 1, it is a naphthalene ring. From the viewpoint of solubility, a benzene ring with m3 being 0 is preferred.

[0310] In formula (a2), m4 is an integer from 0 to 4. The more the number of iodine atoms in the cation structure, especially the higher the absorption of EUV, but the solvent solubility is insufficient, and it may precipitate in the resist composition. Therefore, m4 is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2.

[0311] In formula (a2), m5 is an integer from 0 to 4. From the viewpoint of raw material supply, m5 is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2. m6 is an integer from 0 to 6. From the viewpoint of raw material supply, m6 is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2. m7 is an integer from 0 to 6. From the viewpoint of raw material supply, m7 is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2.

[0312] In formula (a2), m8 is an integer from 0 to 2. From the viewpoint of raw material supply, m8 is preferably 0 or 1. m9 is an integer from 0 to 2. From the viewpoint of raw material supply, m9 is preferably 0 or 1. m10 is an integer from 0 to 2. From the viewpoint of raw material supply, m10 is preferably 0 or 1.

[0313] In formula (a2), m11 is 0 or 1. When m11 is 0, it is a benzene ring, and when m11 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with m11 being 0 is preferred.

[0314] In formula (a2), m12 is an integer from 0 to 4. The more the number of iodine atoms in the cation structure, especially the higher the absorption of EUV, but the solvent solubility is insufficient, and it may precipitate in the resist composition. Therefore, m12 is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2.

[0315] In formula (a2), m13 is an integer from 0 to 2. From the viewpoint of raw material supply, m13 is preferably 0 or 1. m14 is an integer from 0 to 2. From the viewpoint of synthesis, m14 is preferably 0 or 1.

[0316] However, when m1 = 0, 0 ≤ m6 + m9 ≤ 4; when m1 = 1, 0 ≤ m6 + m9 ≤ 6. When m2 = 0, 0 ≤ m7 + m10 ≤ 4; when m2 = 1, 0 ≤ m7 + m10 ≤ 6. When m3 = 0, 1 ≤ m4 + m5 + m8 + m14 ≤ 4; when m3 = 1, 1 ≤ m4 + m5 + m8 + m14 ≤ 6. When m11 = 0, 0 ≤ m12 + m13 ≤ 4; when m11 = 1, 0 ≤ m12 + m13 ≤ 6. Also, m4 + m12 ≥ 1.

[0317] In formula (a2), R F1 ~R F3 are each independently a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms. Among these, trifluoromethyl, trifluoromethoxy, and trifluorothiomethoxy are preferred. When m6 is 2 or more, each R F1 may be the same or different from each other. When m7 is 2 or more, each R F2 may be the same or different from each other. When m5 is 2 or more, each R F3 may be the same or different from each other.

[0318] In formula (a2), R 3 ~R 6 are a halogen atom other than an iodine atom and a fluorine atom, a nitro group, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbon thio group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbon moiety of the aforementioned hydrocarbon group, hydrocarbon oxy group, and hydrocarbon thio group may be saturated or unsaturated, and may be linear, branched, or cyclic. As specific examples thereof, the same groups as those exemplified for the hydrocarbon group represented by R 1 can be cited. In addition, a part or all of the hydrogen atoms of the hydrocarbon moiety of the aforementioned hydrocarbon group, hydrocarbon oxy group, and hydrocarbon thio group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of -CH2- of the aforementioned hydrocarbon group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom. 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)-O-C(=O)-), a haloalkyl group, etc.

[0319] In addition, when m8 = 2, the two R 3 may be the same or different from each other, and the two R 3can be bonded to each other and together with the carbon atoms to which they are bonded to form a ring. When m9 is 2, two Rs 4 can be the same as or different from each other, and the two Rs 4 can be bonded to each other and together with the carbon atoms to which they are bonded to form a ring. When m10 is 2, two Rs 5 can be the same as or different from each other, and the two Rs 5 can be bonded to each other and together with the carbon atoms to which they are bonded to form a ring. When m13 is 2, two Rs 6 can be the same as or different from each other, and the two Rs 6 can be bonded to each other and together with the carbon atoms to which they are bonded to form a ring. Specific examples of the ring formed at this time include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. In addition, some or all of the hydrogen atoms in the above ring can be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- in the above ring can be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate ester bonds, carbonate ester bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-O-C(=O)-), haloalkyl groups, etc.

[0320] In addition, the S in the sulfonium cation represented by the formula (a2) + directly bonded aromatic rings can be bonded to each other and together with S + to form a ring. At this time, specific examples of the structure of the aforementioned ring include the structures represented by the following formulas, etc.

[0321] [Chemical formula 96]

[0322]

[0323] In the formula, the dashed line is an atomic bond.

[0324] In the formula (a2), L A2 and L B2 are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate ester bond, a sulfonamide bond, a carbonate ester bond, or a carbamate bond. Among them, L A2 is preferably a single bond, an ether bond, an ester bond, or a sulfonate ester bond, more preferably an ester bond or a sulfonate ester bond. L B2 is preferably a single bond, an ether bond, or an ester bond, more preferably a single bond.

[0325] In the formula (a2), X L2 is a single bond or a C1-C40 alkylene group that may contain heteroatoms. Specific examples of the C1-C40 alkylene group that may contain heteroatoms include and X L1Specific examples of the C1-C40 divalent hydrocarbon group which may contain a hetero atom are shown below, but are not limited thereto.

[0326] As the sulfonium cation represented by the formula (a2), the sulfonium cation represented by the following formula (a2-1) is preferred.

[0327] [Chemical formula 97]

[0328]

[0329] In the formula, m4 to m10, m12 to m14, R F1 ~R F3 , R 3 ~R 6 , L A2 , L B2 and X L2 are the same as above.

[0330] As the cation represented by the formula (a2-1), the cation represented by the following formula (a2-2) is preferred.

[0331] [Chemical formula 98]

[0332]

[0333] In the formula, m4 to m10, R F 1 ~R F3 and R 3 ~R 5 are the same as above.

[0334] Specific examples of the sulfonium cation represented by the formula (a2) are shown below, but are not limited thereto. Note that in the following formulas, Me represents a methyl group.

[0335] [Chemical formula 99]

[0336]

[0337] [Chemical formula 100]

[0338]

[0339] [Chemical formula 101]

[0340]

[0341] [Chemical formula 102]

[0342]

[0343] [Chemical formula 103]

[0344]

[0345] [Chemical Formula 104]

[0346]

[0347] [Chemical Formula 105]

[0348]

[0349] [Chemical Formula 106]

[0350]

[0351] [Chemical Formula 107]

[0352]

[0353] [Chemical Formula 108]

[0354]

[0355] [Chemical Formula 109]

[0356]

[0357] [Chemical Formula 110]

[0358]

[0359] [Chemical Formula 111]

[0360]

[0361] [Chemical Formula 112]

[0362]

[0363] [Chemical Formula 113]

[0364]

[0365] [Chemical Formula 114]

[0366]

[0367] [Chemical Formula 115]

[0368]

[0369] [Chemical Formula 116]

[0370]

[0371] [Chemical Formula 117]

[0372]

[0373] [Chemical formula 118]

[0374]

[0375] [Chemical formula 119]

[0376]

[0377] [Chemical formula 120]

[0378]

[0379] [Chemical formula 121]

[0380]

[0381] [Chemical formula 122]

[0382]

[0383] [Chemical formula 123]

[0384]

[0385] [Chemical formula 124]

[0386]

[0387] [Chemical formula 125]

[0388]

[0389] [Chemical formula 126]

[0390]

[0391] As a specific example of the onium salt type monomer of the present invention, any combination of the above-mentioned anions and cations can be cited.

[0392] The onium salt type monomer of the present invention can be synthesized, for example, by the same method as the sulfonium salt having a polymerizable anion described in Japanese Patent No. 5201363, but is not limited thereto.

[0393] [Polymer]

[0394] The polymer of the present invention contains a repeating unit (hereinafter, also referred to as repeating unit a) of an onium salt type monomer composed of an anion represented by formula (a1) and a cation represented by formula (a2) below.

[0395] The polymer of the present invention is a polymer-bound photoacid generator that functions as a base polymer in a chemically amplified resist composition and as a photoacid generator. The triarylsulfonium cation containing iodine and fluorine atoms generates secondary electrons from the iodine atoms during exposure, particularly in EUV lithography at a wavelength of 13.5 nm, because the EUV absorption of the iodine atom is very large. In addition, due to the electron-withdrawing effect of the fluorine atom, the energy level of the LUMO in the frontier orbital theory is lowered, making it easier to accept the generated secondary electrons, thereby promoting the decomposition of the cation and effectively generating acid. On the other hand, since the fluorosulfonic acid anion containing a polymerizable group and an aromatic ring structure substituted with an iodine atom also contains iodine atoms, secondary electrons are generated, promoting the decomposition of the cation, and achieving high sensitivity through their synergistic effect. In addition, due to the large atomic weight of the iodine atom and the structure in which the generated acid is bonded to the polymer main chain, it has the characteristic of low acid diffusion. In particular, the polymerizable group composed of styrene and vinylnaphthalene structures has rigidity compared to polymerizable groups such as methacrylate, and increases the glass transition temperature (Tg) of the polymer. It is believed that the aromatic rings within or between the base polymers interact with each other (pi-pi stacking effect), so that the base polymers are regularly arranged and exhibit resistance to pattern collapse by the developer during fine pattern formation. In addition, in the etching step after fine pattern formation, the aromatic rings directly bonded to the main chain also exhibit excellent etching resistance. In the aromatic ring substituted with an iodine atom, the iodine atom is bonded to L in formula (a1). B1 The ortho position of the bonded carbon atom is preferred, which can be expected to inhibit rotation of the bond axis between the aromatic ring to which the polymerizable group is bonded and the aromatic ring substituted with an iodine atom. Consequently, excessive diffusion of the generated acid is suppressed, resulting in excellent LWR of line patterns and CDU of hole patterns, and the formation of patterns resistant to pattern collapse. Therefore, the polymer of the present invention is particularly suitable as a material for chemically amplified positive resist compositions.

[0396] The polymer may further include 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).

[0397] [Chemistry 127]

[0398]

[0399] In formulas (b1) and (b2), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0400] In formula (b1), X 1 represents a single bond, phenylene, naphthylene, *-C(=O)-OX 11- or *-C(=O)-NH-X 11 -, the phenylene or naphthylene may be substituted with a hydroxyl group, a nitro group, a cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. X 11 is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. * represents a bond with a carbon atom of the main chain.

[0401] In formula (b2), X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents a bond with a carbon atom of the main chain. R 11 is a halogen, a cyano group, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. a is an integer of 0 to 4, preferably 0 or 1.

[0402] In formulas (b1) and (b2), AL 1 and AL 2 are each independently an acid-labile group. Specific examples of the acid-labile group include, for example, the groups described in JP-A-2013-80033 and JP-A-2013-83821, but are not limited thereto.

[0403] Typically, specific examples of the acid-labile group include those represented by the following formulas (AL-1) to (AL-3).

[0404] [Chemical formula 128]

[0405]

[0406] In the formula, * is a bond.

[0407] In formulas (AL-1) and (AL-2), R L1 and R L2 are each independently a hydrocarbon group having 1 to 40 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, or an iodine atom. The hydrocarbon group may be linear, branched, or cyclic. The hydrocarbon group preferably has 1 to 20 carbon atoms.

[0408] In formula (AL-1), b is an integer of 0 to 10, preferably an integer of 1 to 5.

[0409] In formula (AL-2), R L3 and R L4Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, and an iodine atom. The aforementioned hydrocarbon group may be linear, branched, or cyclic. Additionally, R L2、 R L3 and R L4 Any two of them may be bonded to each other and, together with the carbon atom or carbon and oxygen atoms to which they are bonded, form a ring having 3 to 20 carbon atoms. As the above ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0410] In formula (AL-3), R L5 、R L6 and R L7 Each independently represents a hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, and an iodine atom. The hydrocarbon group may be linear, branched, or cyclic. Additionally, R L5 、R L6 and R L7 Any two of them may be bonded to each other and, together with the carbon atom to which they are bonded, form a ring having 3 to 20 carbon atoms. As the above ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0411] As specific examples of the repeating unit b1, the following repeating units are exemplified, but are not limited thereto. It should be noted that in the following formula, R A and AL 1 Are the same as above.

[0412] [Chemical formula 129]

[0413]

[0414] [Chemical formula 130]

[0415]

[0416] [Chemical formula 131]

[0417]

[0418] [Chemical formula 132]

[0419]

[0420] [Chemical formula 133]

[0421]

[0422] [Chemical formula 134]

[0423]

[0424] [Chemical formula 135]

[0425]

[0426] As specific examples of the repeating unit b2, the repeating units shown below can be cited, but are not limited thereto. It should be noted that in the following formula, R A and AL 2 are the same as those described above.

[0427] [Chemical formula 136]

[0428]

[0429] [Chemical formula 137]

[0430]

[0431] [Chemical formula 138]

[0432]

[0433] The above polymer may further contain a repeating unit represented by the following formula (b3) (hereinafter, also referred to as repeating unit b3).

[0434] [Chemical formula 139]

[0435]

[0436] In formula (b3), b1 is 0 or 1. When b1 is 0, it is a benzene ring, and when b1 is 1, it is a naphthalene ring. From the viewpoint of considering solvent solubility, a benzene ring with b1 = 0 is preferred. b2 is an integer from 0 to 3 when b1 is 0, and an integer from 0 to 5 when b1 is 1. From the viewpoint of raw material supply, b2 is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2.

[0437] In formula (b3), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom and a methyl group are preferred, and a hydrogen atom is more preferred.

[0438] In formula (b3), X 3 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom of the main chain. Among these, a single bond and *-C(=O)-O- are preferred, and a single bond is more preferred.

[0439] In formula (b3), R 12 and R 13Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl; alkenyl groups having 2 to 20 carbon atoms such as vinyl, propenyl, butenyl, 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; aralkyl groups having 7 to 20 carbon atoms such as benzyl, 1-phenylethyl, 2-phenylethyl; groups obtained by combining them, etc. In addition, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and a part of -CH2- of the aforementioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom. 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)-O-C(=O)-), a haloalkyl group, etc.

[0440] In addition, R 12 and R 13 may be bonded to each other and together with the carbon atom to which they are bonded form a ring. Specific examples of the ring formed at this time include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. In addition, a part or all of the hydrogen atoms in the aforementioned ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and a part of -CH2- in the aforementioned ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom. 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)-O-C(=O)-), a haloalkyl group, etc.

[0441] In formula (b3), R 14 represents a halogen atom, a hydroxyl group, a cyano group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom or -N(R 14A )(R 14B ). R 14A and R14B is each independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. The aforementioned halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, more preferably a fluorine atom or an iodine atom. The hydrocarbon group and the hydrocarbon group moieties of the hydrocarbyloxy group, the hydrocarbyloxycarbonyl group and the hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched or cyclic. As specific examples thereof, groups similar to the groups exemplified for the hydrocarbon group represented by R 12 and R 13 can be mentioned. In addition, a part or all of the hydrogen atoms of the above-mentioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- of the above-mentioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. As a result, it may contain a hydroxyl group, a cyano group, fluorine, chlorine, bromine, iodine, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. When b2 is 2 or more, each R 14 may be the same or different from each other.

[0442] In addition, when b2 is 2 or more, a plurality of R 14 may be bonded to each other and form a ring together with the carbon atoms of the aromatic ring to which they are bonded. As specific examples of the ring formed at this time, a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. can be mentioned. In addition, a part or all of the hydrogen atoms in the above-mentioned ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- in the above-mentioned ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. As a result, it may contain a 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)-O-C(=O)-), a haloalkyl group, etc.

[0443] In formula (b3), X 4 is a single bond, an aliphatic alkylene group having 1 to 4 carbon atoms, a carboxyl group, a sulfonyl group or a group obtained by combining them. Among these, from the viewpoint of raw material supply, a single bond, a carbonyl group or a sulfonyl group is preferable, and from the viewpoint of the polar group generated after the reaction, a single bond or a carbonyl group is more preferable.

[0444] In formula (b3), X 5 and X 6 are each independently an oxygen atom or a sulfur atom. However, X 4 and X 6 are bonded to adjacent carbons of the aromatic ring. X 5 and X 6 may be the same or different from each other. From the viewpoint of reactivity, X 5and X 6 Preferably, they are all oxygen atoms.

[0445] As specific examples of the repeating unit b3, the repeating units shown below can be cited, but are not limited thereto. It should be noted that in the following formula, R A is the same as above, and Me is a methyl group. In addition, the bonding positions of various substituents on the aromatic ring can be interchanged with each other.

[0446] [Chemical formula 140]

[0447]

[0448] [Chemical formula 141]

[0449]

[0450] [Chemical formula 142]

[0451]

[0452] [Chemical formula 143]

[0453]

[0454] [Chemical formula 144]

[0455]

[0456] [Chemical formula 145]

[0457]

[0458] [Chemical formula 146]

[0459]

[0460] [Chemical formula 147]

[0461]

[0462] [Chemical formula 148]

[0463]

[0464] [Chemical formula 149]

[0465]

[0466] [Chemical formula 150]

[0467]

[0468] [Chemical formula 151]

[0469]

[0470] [Chemical formula 152]

[0471]

[0472] [Chemical formula 153]

[0473]

[0474] [Chemical formula 154]

[0475]

[0476] [Chemical formula 155]

[0477]

[0478] [Chemical formula 156]

[0479]

[0480] [Chemical formula 157]

[0481]

[0482] [Chemical formula 158]

[0483]

[0484] [Chemical formula 159]

[0485]

[0486] [Chemical formula 160]

[0487]

[0488] [Chemical formula 161]

[0489]

[0490] [Chemical formula 162]

[0491]

[0492] [Chemical formula 163]

[0493]

[0494] [Chemical formula 164]

[0495]

[0496] [Chemical formula 165]

[0497]

[0498] [Chemical Formula 166]

[0499]

[0500] [Chemical Formula 167]

[0501]

[0502] [Chemical Formula 168]

[0503]

[0504] [Chemical Formula 169]

[0505]

[0506] [Chemical Formula 170]

[0507]

[0508] [Chemical Formula 171]

[0509]

[0510] [Chemical Formula 172]

[0511]

[0512] [Chemical Formula 173]

[0513]

[0514] [Chemical Formula 174]

[0515]

[0516] [Chemical Formula 175]

[0517]

[0518] [Chemical Formula 176]

[0519]

[0520] [Chemical Formula 177]

[0521]

[0522] [Chemical Formula 178]

[0523]

[0524] [Chemical Formula 179]

[0525]

[0526] [Chemical formula 180]

[0527]

[0528] [Chemical formula 181]

[0529]

[0530] [Chemical formula 182]

[0531]

[0532] [Chemical formula 183]

[0533]

[0534] [Chemical formula 184]

[0535]

[0536] [Chemical formula 185]

[0537]

[0538] [Chemical formula 186]

[0539]

[0540] [Chemical formula 187]

[0541]

[0542] [Chemical formula 188]

[0543]

[0544] [Chemical formula 189]

[0545]

[0546] It is preferable that the aforementioned polymer further contains a repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit c).

[0547] [Chemical formula 190]

[0548]

[0549] In formula (c1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * represents a bond to a carbon atom in the main chain,

[0550] R21 is a halogen atom, nitro group, cyano group, carboxyl group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon group carbonyl having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon group carbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom.

[0551] c is an integer of 1 to 4, d is an integer of 0 to 3, provided that 1 ≤ c + d ≤ 5.

[0552] Specific examples of the repeating unit c are listed below, but are not limited thereto. Also, in the following formula, R A As described above.

[0553] [Chemical formula 191]

[0554]

[0555] [Chemical formula 192]

[0556]

[0557] [Chemical formula 193]

[0558]

[0559] [Chemical formula 194]

[0560]

[0561] [Chemical formula 195]

[0562]

[0563] The above polymer preferably further contains a repeating unit represented by the following formula (d1) (hereinafter, also referred to as repeating unit d).

[0564] [Chemical formula 196]

[0565]

[0566] In the formula (d1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Z 1 represents a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-Z 11 -, or *-C(=O)-NH-Z 11 -, and the phenylene group or naphthylene group may be substituted with a hydroxyl group, a nitro group, a cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. * represents a bond with a carbon atom of the main chain. Z 11is a saturated alkylene group, phenylene group or naphthylene group having 1 to 10 carbon atoms, and the saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. R 31 is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one or more structures selected from hydroxyl groups other than phenolic hydroxyl groups, cyano groups, carbonyl groups, carboxyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings and carboxylic anhydrides (-C(=O)-O-C(=O)-).

[0567] As specific examples of the repeating unit d, the repeating units shown below can be cited, but are not limited thereto. It should be noted that in the following formula, R A is the same as the above.

[0568] [Chemical formula 197]

[0569]

[0570] [Chemical formula 198]

[0571]

[0572] [Chemical formula 199]

[0573]

[0574] [Chemical formula 200]

[0575]

[0576] [Chemical formula 201]

[0577]

[0578] [Chemical formula 202]

[0579]

[0580] [Chemical formula 203]

[0581]

[0582] [Chemical formula 204]

[0583]

[0584] [Chemical formula 205]

[0585]

[0586] [Chemical formula 206]

[0587]

[0588] [Chemical formula 207]

[0589]

[0590] [Chemical formula 208]

[0591]

[0592] [Chemical formula 209]

[0593]

[0594] [Chemical formula 210]

[0595]

[0596] [Chemical formula 211]

[0597]

[0598] [Chemical formula 212]

[0599]

[0600] As the repeating unit d, in ArF lithography, a repeating unit having a lactone ring as a polar group is particularly preferred. In KrF lithography, EB lithography, and EUV lithography, a repeating unit having a phenolic moiety is preferred.

[0601] The above 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 e). As the repeating unit e, as long as it has a structure in which one or more hydroxyl groups are protected and the protecting group decomposes by the action of an acid to generate a hydroxyl group, there is no particular limitation, and a repeating unit represented by the following formula (e1) is preferred.

[0602] [Chemical formula 213]

[0603]

[0604] In formula (e1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 41 is an (e + 1)-valent hydrocarbon group having 1 to 30 carbon atoms that may contain a heteroatom. R 42 is an acid-labile group. e is an integer from 1 to 4.

[0605] In formula (e1), the acid-labile group represented by R 42 is a group that is deprotected by the action of an acid to generate a hydroxyl group. The structure of R 42 is not particularly limited, and a acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (e2), etc. are preferred, and an alkoxymethyl group represented by the following formula (e2) is particularly preferred.

[0606] [Chemical formula 214]

[0607]

[0608] In the formula, * represents an atomic bond. R 43 is a hydrocarbon group having 1 to 15 carbon atoms.

[0609] R 42 Specific examples of the acid-labile group represented by and the alkoxymethyl group represented by formula (e2) and the repeating unit e are the same as those exemplified in the description of the repeating unit d described in Japanese Patent Application Laid-Open No. 2020-111564.

[0610] The aforementioned polymer may further contain a repeating unit f derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or their derivatives. Specific examples of the monomer that provides the repeating unit f include the monomers shown below, but are not limited thereto.

[0611] [Chemical formula 215]

[0612]

[0613] The aforementioned polymer may further contain a repeating unit g derived from styrene, indene, vinylpyridine or vinylcarbazole.

[0614] In the polymer of the present invention, the content ratios of the repeating units a, b1, b2, b3, c, d, e, f and g are preferably 0 < a ≤ 0.5, 0 ≤ b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 ≤ b3 ≤ 0.6, 0 ≤ c ≤ 0.8, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.3, 0 ≤ f ≤ 0.3 and 0 ≤ g ≤ 0.3, more preferably 0 < a ≤ 0.4, 0 ≤ b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 ≤ b3 ≤ 0.5, 0 ≤ c ≤ 0.7, 0 ≤ d ≤ 0.4, 0 ≤ e ≤ 0.2, 0 ≤ f ≤ 0.2 and 0 ≤ g ≤ 0.2. Among them, a + b1 + b2 + b3 + c + d + e + f + g ≤ 1.0.

[0615] The weight average molecular weight (Mw) of the above polymer is preferably 1000 to 500000, more preferably 3000 to 100000. If Mw is in this range, sufficient etching resistance can be obtained, and there is no concern about a decrease in resolution due to the inability to ensure a difference in dissolution rate before and after exposure. It should be noted that 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.

[0616] Furthermore, regarding the molecular weight distribution (Mw / Mn) of the aforementioned polymer, as the pattern rules become finer, the influence of Mw / Mn tends to increase. Therefore, in order to obtain a resist composition suitable for use in fine pattern sizes, it is preferable that Mw / Mn is a narrow dispersion of 1.0 to 2.0. If it is within the aforementioned range, there are few low-molecular-weight and high-molecular-weight polymers, and after exposure, there is no risk of seeing foreign substances on the pattern or the shape of the pattern deteriorating.

[0617] As a method for synthesizing the above polymer, for example, a method can be cited in which a monomer providing the above repeating unit is added with a radical polymerization initiator in an organic solvent and heated to polymerize it.

[0618] Specific examples of the organic solvent used during polymerization include: toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), etc. Specific examples of the above polymerization initiator include: 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, etc. The addition amount of these initiators is preferably 0.01 to 25 mol% relative to the total of the monomers to be polymerized. The reaction temperature is preferably 50 to 150 °C, more preferably 60 to 100 °C. The reaction time is preferably 2 to 24 hours, and from the viewpoint of production efficiency, more preferably 2 to 12 hours.

[0619] The above polymerization initiator can be added to the above monomer solvent and supplied to the reaction kettle, or an initiator solution can be prepared separately from the above monomer solvent, and they can be supplied to the reaction kettle independently. Since there is a possibility of polymerization reaction and formation of ultra-high molecular weight bodies due to free radicals generated from the initiator during the standby time, from the viewpoint of quality control, it is preferable to prepare the monomer solution and the initiator solution independently and perform dropping. The acid-labile group can directly use the group introduced into the monomer, or it can be protected or partially protected after polymerization. In addition, in order to adjust the molecular weight, known chain transfer agents such as dodecanethiol and 2-mercaptoethanol can also be used in combination. In this case, the addition amount of these chain transfer agents is preferably 0.01 to 20 mol% relative to the total of the monomers to be polymerized.

[0620] In the case of a monomer containing a hydroxyl group, during polymerization, the hydroxyl group can be replaced with an acetal group such as ethoxyethoxy that is easily deprotected by an acid, and deprotected with a weak acid and water after polymerization, or it can be replaced with an acetyl group, a formyl group, a trimethylacetyl group, etc., and subjected to base hydrolysis after polymerization.

[0621] In the case of copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers can be heated and polymerized by adding a radical polymerization initiator in an organic solvent, or acetoxystyrene or acetoxyvinylnaphthalene can be used, and after polymerization, the acetoxy group can be deprotected by alkali hydrolysis to produce polyhydroxystyrene or hydroxyvinylnaphthalene.

[0622] As specific examples of the base for alkali hydrolysis, ammonia water, triethylamine, etc. can be used. In addition, the reaction temperature is preferably -20 to 100 °C, more preferably 0 to 60 °C. In addition, the reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0623] It should be noted that the amounts of the respective monomers in the above monomer solution can be appropriately set, for example, in such a manner that the content ratio is preferably the above repeating unit.

[0624] For the polymer obtained by the above manufacturing method, the reaction solution obtained by the polymerization reaction can be used as the final product, or the powder obtained by a purification step such as a reprecipitation method in which the polymerization solution is added to a poor solvent to obtain a powder can be used as the final product. From the viewpoints of operation efficiency and quality stabilization, it is preferably to use the polymer solution obtained by dissolving the powder obtained by the purification step in a solvent as the final product.

[0625] As specific examples of the solvent used at this time, ketones such as cyclohexanone and methyl-2-n-amyl ketone described in paragraphs

[0144] to

[0145] of JP-A No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monoter-butyl ether acetate; lactones such as GBL; alcohols such as diacetone alcohol (DAA); high-boiling alcohol solvents such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol; and mixed solvents thereof.

[0626] In the above polymer solution, the concentration of the polymer is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0627] The above reaction solution and polymer solution are preferably filtered through a filter. By performing filter filtration, foreign matters and gels that may cause defects can be removed, which is effective in terms of quality stabilization.

[0628] As the material of the filter used in the aforementioned filtration of the filter, filters made of materials such as fluorocarbon-based, cellulose-based, nylon-based, polyester-based, and hydrocarbon-based materials can be cited. In the filtration step of the chemically amplified resist composition, a filter made of a fluorocarbon-based material such as so-called Teflon (registered trademark), a hydrocarbon-based material such as polyethylene or polypropylene, or nylon is preferably used. The pore diameter of the filter can be appropriately selected according to the target cleanliness, preferably 100 nm or less, more preferably 20 nm or less. In addition, one of these filters can be used alone, or multiple filters can be used in combination. The filtration method can be carried out by passing the solution only once, but more preferably, the solution is circulated for multiple filtrations. The filtration step can be carried out in any order and number in the polymer manufacturing step, and preferably, the reaction solution, polymer solution, or both after the polymerization reaction are filtered.

[0629] [Chemically Amplified Resist Composition]

[0630] [(A) Base Polymer]

[0631] The chemically amplified resist composition of the present invention contains a base polymer containing the above polymer as component (A).

[0632] The above polymers can be used alone, or two or more polymers having different composition ratios, Mw, and / or Mw / Mn can be used in combination. In addition, the (A) base polymer may contain a hydride of a ring-opening metathesis polymer, and in this regard, the substances described in JP-A-2003-66612 can be used.

[0633] [(B) Quencher]

[0634] The chemically amplified resist composition of the present invention may contain a quencher as component (B). It should be noted that in the present invention, a quencher refers to a material that prevents the acid generated by the photoacid generator in the chemically amplified resist composition from diffusing to the unexposed portion by capturing the acid, thereby forming a desired pattern.

[0635] As a specific example of the (B) quencher, an onium salt represented by the following formula (1) or (2) can be cited.

[0636] [Chemical Formula 216]

[0637]

[0638] In formula (1), R q1 is a hydrogen atom, or a hydrocarbon group having 1 to 40 carbon atoms that may also contain a hetero atom, provided that the hydrogen atom bonded to the α-position carbon atom of the sulfonyl group is not substituted with a fluorine atom or a fluoroalkyl group. In formula (2), R q2 is a hydrogen atom, or a hydrocarbon group having 1 to 40 carbon atoms that may also contain a hetero atom.

[0639] R q1 represents a hydrocarbon group having 1 to 40 carbon atoms. Specifically, examples include: alkyl groups having 1 to 40 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl; cycloalkyl groups having 3 to 40 carbon atoms such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6 decyl, adamantyl; aryl groups having 6 to 40 carbon atoms such as phenyl, naphthyl, anthryl. In addition, a part or all of the hydrogen atoms of the above hydrocarbon groups may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of -CH2- of the above hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a 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)-O-C(=O)-), a haloalkyl group, etc.

[0640] R q2 represents a hydrocarbon group. Specifically, in addition to the substituents exemplified as specific examples of R q1 , fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl can also be cited.

[0641] Specific examples of the anion of the onium salt represented by formula (1) include those shown below, but are not limited thereto.

[0642] [Chemical formula 217]

[0643]

[0644] [Chemical formula 218]

[0645]

[0646] [Chemical formula 219]

[0647]

[0648] Specific examples of the anion of the onium salt represented by formula (2) include those shown below, but are not limited thereto.

[0649] [Chemical formula 220]

[0650]

[0651] [Chemical formula 221]

[0652]

[0653] [Chemical formula 222]

[0654]

[0655] In formulas (1) and (2), Mq + is an onium cation. As the above onium cation, 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) is preferred.

[0656] [Chemical formula 223]

[0657]

[0658] In formulas (cation-1) and (cation-2), R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom.

[0659] R ct1 ~R ct5 Specific examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.

[0660] R ct1 ~R ct5 The hydrocarbon group represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl; cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl; alkenyl groups having 2 to 30 carbon atoms such as vinyl, propenyl, butenyl, 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, thienyl; aralkyl groups having 7 to 30 carbon atoms such as benzyl, 1-phenylethyl, 2-phenylethyl; groups obtained by combining them, etc., but aryl groups are preferred. In addition, part or all of the hydrogen atoms of the above hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and -CH2- or part of the above hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0661] In addition, R ct1 and R ct2 can be bonded to each other and together with the sulfur atom to which they are bonded form a ring. At this time, as a specific example of the structure of the aforementioned ring, the structure represented by the following formula etc. can be cited.

[0662] [Chemical formula 224]

[0663]

[0664] Among them, the dotted line represents the atomic bond with R ct3 .

[0665] As specific examples of the sulfonium cation represented by formula (cation-1), those shown below can be cited, but are not limited to these.

[0666] [Chemical formula 225]

[0667]

[0668] [Chemical formula 226]

[0669]

[0670] [Chemical formula 227]

[0671]

[0672] [Chemical formula 228]

[0673]

[0674] [Chemical formula 229]

[0675]

[0676] [Chemical formula 230]

[0677]

[0678] [Chemical formula 231]

[0679]

[0680] [Chemical formula 232]

[0681]

[0682] [Chemical formula 233]

[0683]

[0684] [Chemical formula 234]

[0685]

[0686] [Chemical formula 235]

[0687]

[0688] [Chemical formula 236]

[0689]

[0690] [Chemical formula 237]

[0691]

[0692] [Chemical formula 238]

[0693]

[0694] [Chemical formula 239]

[0695]

[0696] [Chemical formula 240]

[0697]

[0698] [Chemical formula 241]

[0699]

[0700] [Chemical formula 242]

[0701]

[0702] [Chemical formula 243]

[0703]

[0704] [Chemical formula 244]

[0705]

[0706] [Chemical formula 245]

[0707]

[0708] [Chemical formula 246]

[0709]

[0710] [Chemical formula 247]

[0711]

[0712] [Chemical formula 248]

[0713]

[0714] [Chemical 249]

[0715]

[0716] [Chemical 250]

[0717]

[0718] [Chemical 251]

[0719]

[0720] Specific examples of the oxonium cation represented by formula (cation-2) are listed below, but are not limited thereto.

[0721] [Chemical 252]

[0722]

[0723] [Chemical 253]

[0724]

[0725] In formula (cation-3), R ct6 ~R ct9 are each independently a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. Further, R ct6 and R ct7 may be bonded to each other and together with the nitrogen atom to which they are bonded form a ring. Specific examples of the above hydrocarbon group are, for example, the same groups as those exemplified for the hydrocarbon group represented by R ct1 ~R ct5 in the description of formulas (cation-1) and (cation-2).

[0726] Specific examples of the ammonium cation represented by formula (cation-3) are shown below, but are not limited to these.

[0727] [Chemical 254]

[0728]

[0729] Specific examples of the onium salt represented by formula (1) or formula (2) can be any combination of the aforementioned anions and cations. It should be noted that these onium salts can be easily prepared by an ion exchange reaction using known organic chemical methods. Regarding the ion exchange reaction, for example, reference can be made to Japanese Patent Application Laid-Open No. 2007-145797.

[0730] The onium salt represented by formula (1) or (2) acts as a quencher in the chemically amplified resist composition of the present invention. This is because each counter anion of the above onium salt is a conjugate base of a weak acid. The weak acid mentioned here refers to a weak acid that exhibits an acidity that cannot deprotect the acid-labile group of the unit containing an acid-labile group used in the base polymer. That is, the onium salt represented by formula (1) or (2) functions as a quencher when used in combination with an onium salt type photoacid generator having a conjugate base of a strong acid such as a sulfonic acid with a fluorinated α-position as a counter anion. That is, when an onium salt that generates a strong acid such as a sulfonic acid with a fluorinated α-position is mixed with an onium salt that generates a weak acid such as a non-fluorinated sulfonic acid or carboxylic acid, if the strong acid generated by the photoacid generator by high-energy ray irradiation collides with the unreacted onium salt having a weak acid anion, the weak acid is released by salt exchange, and an onium salt having a strong acid anion is generated. In this process, the strong acid is exchanged for a weak acid with lower catalytic ability. Therefore, apparently, the acid is inactivated and the control of acid diffusion can be carried out.

[0731] In addition, as the (B) quencher, an onium salt having a sulfonium cation and a phenolate anion moiety in the same molecule described in Japanese Patent No. 6848776, an onium salt having a sulfonium cation and a carboxylate anion moiety in the same molecule described in Japanese Patent No. 6583136 and Japanese Patent Application Laid-Open No. 2020-200311, and an onium salt having an iodonium cation and a carboxylate anion moiety in the same molecule described in Japanese Patent No. 6274755 can also be used.

[0732] Here, it is considered that when the photoacid generator that generates a strong acid is an onium salt, as described above, the strong acid generated by high-energy ray irradiation can be exchanged for a weak acid. On the other hand, the weak acid generated by high-energy ray irradiation is difficult to collide with the unreacted onium salt that generates a strong acid for salt exchange. This is due to the phenomenon that the onium cation is more likely to form an ion pair with the anion of the strong acid.

[0733] When the chemically amplified resist composition of the present invention contains the onium salt represented by formula (1) or (2) as the (B) quencher, its content is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, relative to 80 parts by mass of the (A) base polymer. If the onium salt type quencher of the (B) component is within the above range, the resolution is good and the sensitivity will not be significantly reduced, so it is preferred. The onium salt represented by formula (1) or (2) can be used alone or in combination of two or more.

[0734] The chemically amplified resist composition of the present invention may contain a nitrogen-containing compound as the (B) quencher. As the nitrogen-containing compound of the (B) component, primary, secondary or tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103 can be cited, 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 can be cited. Further, as described in Japanese Patent No. 3790649, compounds in which a primary amine or a secondary amine is protected with a carbamate group can also be cited. Furthermore, as described in JP-A-2009-109595, compounds having an acid-labile group in the molecule can also be cited.

[0735] In addition, a sulfonium salt having a nitrogen-containing substituent can also be used as the nitrogen-containing compound. Such a compound functions as a quencher in the unexposed portion, and loses its quencher ability by neutralization with the acid generated by itself in the exposed portion, and functions as a so-called photo-decomposable base. By using a photo-decomposable base, the contrast between the exposed portion and the unexposed portion can be further enhanced. As the photo-decomposable base, for example, reference can be made to JP-A-2009-109595, JP-A-2012-46501, etc.

[0736] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as the (B) 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 (A) base polymer. The above nitrogen-containing compounds can be used alone or in combination of two or more.

[0737] [(C) Organic solvent]

[0738] The chemically amplified resist composition of the present invention may contain an organic solvent as the component (C). The (C) organic solvent is not particularly limited as long as it can dissolve the foregoing components and the following components. Specific examples of such an organic solvent 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; ketol such as DAA; ethers such as PGME, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monoter-butyl ether acetate; lactones such as GBL; and mixed solvents thereof.

[0739] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and their mixed solvents, in which the solubility of the base polymer of component (A) is particularly excellent, are preferred.

[0740] In the chemically amplified resist composition of the present invention, the content of (C) organic solvent is preferably 200 to 5000 parts by mass, more preferably 400 to 3500 parts by mass, relative to 80 parts by mass of (A) base polymer. (C) The organic solvent can be used alone or in combination of two or more.

[0741] [(D) Acid generator]

[0742] The chemically amplified resist composition of the present invention may contain an acid generator within a range not detrimental to the effects of the present invention. As the above acid generator, an acid generator (photoacid generator) that generates an acid upon irradiation with actinic light or radiation can be mentioned. As the photoacid generator, as long as it is an acid generator that generates an acid upon irradiation with high-energy rays, there is no particular limitation, and an acid generator that generates sulfonic acid, imidic acid, or methide acid is preferred. As the preferred photoacid generators, there are sulfonium salts, iodonium salts, sulfonyldiazomethanes, N-sulfonyloxyimides, oxime-O-sulfonate type acid generators, etc. As specific examples of the acid generator, the acid generators described in paragraphs

[0122] to

[0142] of Japanese Patent Laid-Open No. 2008-111103 can be mentioned.

[0743] In addition, as the photoacid generator, the sulfonium salt represented by the following formula (3-1) and the iodonium salt represented by the following formula (3-2) can also be suitably used.

[0744] [Chemical formula 255]

[0745]

[0746] In formulas (3-1) and (3-2), R 101 ~R 105 are each independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. As specific examples of the above halogen atom and hydrocarbon group, for example, the same as those for R ct1 ~R ct5Groups similar to the groups exemplified for the halogen atom and the hydrocarbon group represented. In addition, part or all of the hydrogen atoms of the above hydrocarbon group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the -CH2- of the above hydrocarbon group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonate ester bonds, carbonate ester bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-O-C(=O)-), haloalkyl groups, etc. In addition, R 101 and R 102 may be bonded to each other and together with the sulfur atom to which they are bonded form a ring. As a specific example of the ring formed at this time, for example, in the description of formula (cation-1), for R ct1 and R ct2 bonded to each other and together with the sulfur atom to which they are bonded, it is the same ring as the ring exemplified as the ring that can be formed.

[0747] In addition, as a specific example of the cation of the sulfonium salt represented by formula (3-1), cations similar to the cations exemplified as the oxonium cations represented by formula (cation-2) can be cited. In addition, as a specific example of the cation of the sulfonium salt represented by formula (3-2), cations similar to the cations exemplified as the oxonium cations represented by formula (cation-2) can be cited.

[0748] In formulas (3-1) and (3-2), Xa - is an anion selected from the following formulas (3A) to (3D).

[0749] [Chemical formula 256]

[0750]

[0751] In formula (3A), R fa is a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms containing a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. As specific examples thereof, substances similar to those exemplified in the description of R fa1 of formula (3A') described later can be cited.

[0752] As the anion represented by formula (3A), a group represented by the following formula (3A') is preferred.

[0753] [Chemical formula 257]

[0754]

[0755] In formula (3A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0756] In formula (3A)'), R fa1 is a hydrocarbon group having 1 to 38 carbon atoms which may contain a heteroatom. The aforementioned heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and more preferably an oxygen atom. From the viewpoint of obtaining high resolution in the formation of a fine pattern, the hydrocarbon group is particularly preferably a hydrocarbon group having 6 to 30 carbon atoms.

[0757] R fa1 The hydrocarbon group having 1 to 38 carbon atoms represented 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, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, icosyl; cycloalkyl saturated hydrocarbon groups having 3 to 38 carbon atoms such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, dicyclohexylmethyl; unsaturated aliphatic hydrocarbon groups having 2 to 38 carbon atoms such as allyl, 3-cyclohexenyl; aryl groups having 6 to 38 carbon atoms such as phenyl, 1-naphthyl, 2-naphthyl; aralkyl groups having 7 to 38 carbon atoms such as benzyl, diphenylmethyl; groups obtained by combining them, etc.

[0758] In addition, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- of the aforementioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc. As a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. It should be noted that as the aforementioned heteroatom, an oxygen atom is preferred. 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, 3-oxocyclohexyl, etc.

[0759] The synthesis of sulfonium salts containing anions represented by formula (3A)' is described in detail in Japanese Patent Application Laid-Open No. 2007-145797, Japanese Patent Application Laid-Open No. 2008-106045, Japanese Patent Application Laid-Open No. 2009-7327, Japanese Patent Application Laid-Open No. 2009-258695, etc. In addition, it is also preferred to use sulfonium salts described in Japanese Patent Application Laid-Open No. 2010-215608, Japanese Patent Application Laid-Open No. 2012-41320, Japanese Patent Application Laid-Open No. 2012-106986, Japanese Patent Application Laid-Open No. 2012-153644, etc.

[0760] Specific examples of the anion represented by formula (3A) include those shown below, but are not limited thereto. In the following formula, Ac represents an acetyl group.

[0761] [Chemistry 258]

[0762]

[0763] [Chemistry 259]

[0764]

[0765] [Chemistry 260]

[0766]

[0767] [Chemistry 261]

[0768]

[0769] In formula (3B), 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 heteroatom. The hydrocarbon group may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include R in formula (3A'): fa1 The same groups as those exemplified for the hydrocarbon groups represented by R fb1 and R fb2 It is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 Can bond to each other and to the groups to which they are bonded (-CF2-SO2-N - -SO2-CF2-) together to form a ring, at this time, R fb1 and R fb2 The group obtained by bonding to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0770] In formula (3C), R fc1 、R fc2 and R fc3Each independently is a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. As specific examples thereof, groups similar to the groups exemplified by the hydrocarbon group represented by R in formula (3A') can be cited. fa1 The hydrocarbon group represented by fc1 R fc2 and R fc3 are preferably a fluorine atom or a linear fluoroalkyl group having 1 to 4 carbon atoms. In addition, R fc1 and R fc2 may be bonded to each other and together with the group (-CF2-SO2-C - -SO2-CF2-) to which they are bonded form a ring. In this case, the group obtained by bonding R fc1 and R fc2 to each other is preferably fluoroethylene or fluoropropylene.

[0771] In formula (3D), R fd is a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. As specific examples thereof, groups similar to the groups exemplified by the hydrocarbon group represented by R in formula (3A') can be cited. fa1 The same groups as those exemplified by the hydrocarbon group represented by

[0772] For the synthesis of the sulfonium salt containing the anion represented by formula (3D), refer to Japanese Patent Application Laid-Open No. 2010-215608 and Japanese Patent Application Laid-Open No. 2014-133723 for details.

[0773] As specific examples of the anion represented by formula (3D), those shown below can be cited, but are not limited thereto.

[0774] [Chemical formula 262]

[0775]

[0776] [Chemical formula 263]

[0777]

[0778] It should be noted that the photoacid generator containing the anion represented by formula (3D) does not have a fluorine atom at the α-position of the sulfonyl group, but since it has two trifluoromethyl groups at the β-position, it has an acidity sufficient to cleave the acid-labile group in the base polymer. Therefore, it can be used as a photoacid generator.

[0779] As the photoacid generator, it is also preferable to use a substance represented by the following formula (4).

[0780] [Chemical formula 264]

[0781]

[0782] In formula (4), R 201 and R 202 are each independently a hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. R 203 is a divalent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. Further, any two of R 201 , R 202 and R 203 may be bonded to each other and together with the sulfur atom to which they are bonded form a ring. At this time, as a specific example of the above ring, for example, the same rings as those exemplified for the rings that R ct1 and R ct2 can be bonded to each other and together with the sulfur atom to which they are bonded form in the description of formula (cation-1).

[0783] The hydrocarbon group having 1 to 30 carbon atoms represented by R 201 and R 202 may be saturated or unsaturated, and may be linear, branched or cyclic. As specific examples thereof, alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl; cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6 decyl, 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, anthryl; groups obtained by combining them, etc. Further, a part or all of the hydrogen atoms of the above hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and a part of -CH2- of the above hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0784] R 203The C1-C30 alkylene group represented can be saturated or unsaturated, and can be linear, 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, heptadecane-1,17-diyl and other C1-C30 alkanediyl groups; cyclopentanediyl, cyclohexanediyl, norbornanediy, adamantanediyl and other C3-C30 cyclic saturated alkylene groups; phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, tert-butylnaphthylene and other C6-C30 arylene groups; groups obtained by combining them, etc. In addition, part or all of the hydrogen atoms of the above alkylene group can be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and part or all of the -CH2- of the above alkylene group can be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc. As a result, it can contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate ester bonds, carbonate ester bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-O-C(=O)-), haloalkyl groups, etc. As the above heteroatom, an oxygen atom is preferably used.

[0785] In formula (4), L 1 is a single bond, or a C1-C20 alkylene group which may contain an ether bond or a heteroatom. The aforementioned alkylene group can be saturated or unsaturated, and can be linear, branched or cyclic. Specific examples thereof include the same groups as those exemplified for the alkylene group represented by R 203 .

[0786] In formula (4), X a , X b , X c and X d are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group. However, at least one of X a , X b , X c and X d is a fluorine atom or a trifluoromethyl group.

[0787] In formula (4), k is an integer from 0 to 3.

[0788] As the photoacid generator represented by formula (4), a group represented by the following formula (4') is preferable.

[0789] [Chemical formula 265]

[0790]

[0791] In formula (4'), L 1 is the same as above. X e is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 301 , R 302 and R 303 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. As specific examples thereof, groups similar to the groups exemplified for the hydrocarbon group represented by R fa1 in formula (3A') can be cited. x and y are each independently an integer from 0 to 5. z is an integer from 0 to 4.

[0792] As a specific example of the photoacid generator represented by formula (4), a photoacid generator similar to the photoacid generator exemplified as the photoacid generator represented by formula (2) in Japanese Patent Application Laid-Open No. 2017-26980 can be cited.

[0793] Among the aforementioned photoacid generators, a compound containing an anion represented by formula (3A') or (3D) has low acid diffusibility and excellent solubility in a solvent, and is therefore particularly preferable. In addition, the compound represented by formula (4') has extremely low acid diffusion and is particularly preferable.

[0794] In addition, as other acid generators, sulfonium salts and iodonium salts containing an anion having an aromatic ring substituted with an iodine atom represented by the following formula (5-1) or formula (5-2) can also be used.

[0795] [Chemical formula 266]

[0796]

[0797] In formulas (5-1) and (5-2), p is 1, 2 or 3. q and r are integers satisfying 1 ≤ q ≤ 5, 0 ≤ r ≤ 3 and 1 ≤ q + r ≤ 5. q is preferably 1, 2 or 3, more preferably 2 or 3. r is preferably 0, 1 or 2.

[0798] In formulas (5-1) and (5-2), L 11 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 aforementioned saturated alkylene group may be linear, branched or cyclic.

[0799] In formulas (5-1) and (5-2), L 12 is a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and a (p + 1)-valent linking group having 1 to 20 carbon atoms when p is 2 or 3. This linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.

[0800] In formulas (5-1) and (5-2), R 401 represents 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 hydrocarbon oxy group having 1 to 20 carbon atoms, a hydrocarbon carbonyl group having 2 to 20 carbon atoms, a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms or a hydrocarbon sulfonyloxy group having 1 to 20 carbon atoms that may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group or an ether bond, or -N(R 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-O-R 401D . R 401A and R 401B are each independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. R 401C 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. R 401D is an aliphatic hydrocarbon group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carboxyl 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 linear, branched or cyclic. The aforementioned hydrocarbon group, hydrocarbon oxy group, hydrocarbon carbonyl group, hydrocarbon oxycarbonyl group, hydrocarbon carbonyloxy group and hydrocarbon sulfonyloxy group may be linear, branched or cyclic. When p and / or r is 2 or more, each R 401 may be the same or different from each other.

[0801] Among them, R 401 is preferably a hydroxyl group, -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-O-R 401D , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group, etc.

[0802] In formulas (5-1) and (5-2), Rf 1 ~Rf 4Each independently is: a hydrogen atom, a fluorine atom or a trifluoromethyl group, provided that at least one of them is a fluorine atom or a trifluoromethyl group. Further, Rf 1 and Rf 2 may combine to form a carbonyl group. In particular, Rf 3 and Rf 4 are preferably both fluorine atoms.

[0803] In formulas (5-1) and (5-2), R 402 ~R 406 each independently is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. As specific examples thereof, for example, the same groups as those exemplified for the hydrocarbon groups represented by R ct1 ~R ct5 in the descriptions of formulas (cation-1) and (cation-2). Further, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone ring, a sulfo group or a group containing a sulfonium salt, and part of -CH2- of the aforementioned hydrocarbon group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond or a sulfonate bond. Further, R 402 and R 403 may bond to each other and form a ring together with the sulfur atom to which they are bonded. At this time, as specific examples of the aforementioned ring, rings the same as those exemplified for the rings that can be formed by bonding R ct1 and R ct2 to each other and forming a ring together with the sulfur atom to which they are bonded in the description of formula (cation-1) can be cited.

[0804] Further, as specific examples of the cation of the sulfonium salt represented by formula (5-1), the same cations as those exemplified as the sulfonium cations represented by formula (cation-1) can be cited. Further, as specific examples of the cation of the oxonium salt represented by formula (5-2), the same cations as those exemplified as the oxonium cations represented by formula (cation-2) can be cited.

[0805] As specific examples of the anion of the onium salt represented by formula (5-1) or (5-2), those shown below can be cited, but are not limited thereto.

[0806] [Chemical formula 267]

[0807]

[0808] [Chemical formula 268]

[0809]

[0810] [Chemical formula 269]

[0811]

[0812] [Chemical formula 270]

[0813]

[0814] [Chemical formula 271]

[0815]

[0816] [Chemical formula 272]

[0817]

[0818] [Chemical formula 273]

[0819]

[0820] [Chemical formula 274]

[0821]

[0822] [Chemical formula 275]

[0823]

[0824] [Chemical formula 276]

[0825]

[0826] [Chemical formula 277]

[0827]

[0828] [Chemical formula 278]

[0829]

[0830] [Chemical formula 279]

[0831]

[0832] [Chemical formula 280]

[0833]

[0834] [Chemical formula 281]

[0835]

[0836] [Chemical formula 282]

[0837]

[0838] [Chemical formula 283]

[0839]

[0840] [Chemical formula 284]

[0841]

[0842] [Chemical formula 285]

[0843]

[0844] [Chemical formula 286]

[0845]

[0846] [Chemical formula 287]

[0847]

[0848] [Chemical formula 288]

[0849]

[0850] When the chemically amplified resist composition of the present invention contains (D) an acid generator, its content is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 20 parts by mass, relative to 80 parts by mass of (A) the base polymer. If the addition amount of the (D) acid generator is within the above range, the resolution is good, and there will be no problem of foreign matter during the development or peeling of the resist film, so it is preferred. The (D) acid generator can be used alone as one kind, or two or more kinds can be used in combination.

[0851] [(E) Surfactant]

[0852] The chemically amplified resist composition of the present invention may further contain a surfactant as the (E) component. As the (E) surfactant, a surfactant that is insoluble or hardly soluble in water and soluble in an alkali developer, or a surfactant that is insoluble or hardly soluble in water and an alkali developer is preferred. As such a surfactant, reference can be made to the surfactants described in Japanese Patent Application Laid-Open No. 2010-215608 and Japanese Patent Application Laid-Open No. 2011-16746.

[0853] As the surfactant that is insoluble or hardly soluble in water and an alkali developer, among the surfactants described in the above publications, FC-4430 (manufactured by 3M), Surflon (registered trademark) S-381 (manufactured by AGC SEIMICHEMICAL Co., Ltd.), Olfine (registered trademark) E1004 (manufactured by Nissin Chemical Industry 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 preferred.

[0854] [Chemical formula 289]

[0855]

[0856] Here, R, Rf, A, B, C, m, and n are not related to the foregoing description and are only applicable to formula (surf-1). R is an aliphatic group with a valence of 2 to 4 and 2 to 5 carbon atoms. As the foregoing aliphatic group, as a divalent group, examples include ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentylene, etc. As a trivalent or tetravalent group, the following groups can be cited.

[0857] [Chemical formula 290]

[0858]

[0859] In the formula, the dotted lines are atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.

[0860] Among them, 1,4-butylene, 2,2-dimethyl-1,3-propylene, etc. are preferred.

[0861] Rf is trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. m is an integer from 0 to 3, n is an integer from 1 to 4, and the sum of n and m is the valence of R, which is an integer from 2 to 4. A is 1. B is an integer from 2 to 25, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. In addition, the arrangement of each structural unit in formula (surf-1) is not specified, and they can be block-bonded or randomly bonded. The manufacture of surfactants based on partially fluorinated oxetane ring-opening polymers is described in detail in, for example, the specification of U.S. Patent No. 5650483.

[0862] In the case of not using a resist protective film in ArF immersion lithography, a surfactant that is insoluble or hardly soluble in water but soluble in an alkaline developer has the function of reducing the infiltration or exudation of water by aligning on the surface of the resist film. Therefore, it can be used to reduce the damage to the exposure apparatus by suppressing the elution of water-soluble components from the resist film, and dissolve during alkaline aqueous solution development after exposure or post-exposure bake (PEB), and is unlikely to become a foreign substance causing defects. Such a surfactant has the property of being insoluble or hardly soluble in water but soluble in an alkaline developer, is a polymer-type surfactant, and is also called a hydrophobic resin. Particularly preferably, it is a surfactant with high water repellency and improved lubricity.

[0863] As a specific example of such a polymer-type surfactant, a polymer-type surfactant containing at least one kind of repeating unit selected from those represented by the following formulas (6A) to (6E) can be cited.

[0864] [Chemical formula 291]

[0865]

[0866] In formulas (6A) to (6E), R B is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. W 1 is -CH2-, -CH2CH2-, -O- or two separate -H's. R s1 are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R s2 is a single bond or a linear or branched alkylene group having 1 to 5 carbon atoms. R s3 are each independently a hydrogen atom, a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group. R s3 When it is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group can be inserted between carbon-carbon bonds. R s4 is a (u + 1)-valent hydrocarbon group or fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer from 1 to 3. R s5 each independently represents a hydrogen atom, or a group represented by -C(=O)-O-R sa represents the group. R sa is a fluorinated hydrocarbon group having 1 to 20 carbon atoms. R s6 is a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, and an ether bond or a carbonyl group can be inserted between its carbon-carbon bonds.

[0867] R s1 The hydrocarbon group having 1 to 10 carbon atoms represented by is preferably a saturated hydrocarbon group, and can be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl; cyclic saturated hydrocarbon groups having 3 to 10 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, norbornyl, etc. Among them, an alkyl group having 1 to 6 carbon atoms is preferred.

[0868] R s2 The alkylene group represented by is preferably a saturated alkylene group, and can be linear, branched or cyclic. Specific examples thereof include methylene, ethylene, propylene, butylene, pentylene, etc.

[0869] R s3 or R s6 The hydrocarbon group represented by can be saturated or unsaturated, and can be linear, branched or cyclic. Specific examples thereof include saturated hydrocarbon groups, aliphatic unsaturated hydrocarbon groups such as alkenyl groups and alkynyl groups, etc., and a saturated hydrocarbon group is preferred. Specific examples of the above saturated hydrocarbon groups include R s1The hydrocarbon group represented, in addition to this, includes undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, etc. R s3 or R s6 Specific examples of the fluoroalkyl group represented include groups in which a part or all of the hydrogen atoms bonded to the carbon of the aforementioned hydrocarbon group are substituted with fluorine atoms. As described above, an ether bond or a carbonyl group may be inserted between these carbon-carbon bonds.

[0870] R s3 Specific examples of the acid-labile group represented include the groups represented by the aforementioned formula (AL-3) to formula (AL-5), trialkylsilyl groups in which each alkyl group is an alkyl group having 1 to 6 carbon atoms, alkyl groups having 4 to 20 carbon atoms containing an oxo group, etc.

[0871] R s4 The (u + 1)-valent hydrocarbon group or fluoroalkyl group represented by R may be linear, branched, or cyclic. As specific examples thereof, groups obtained by further removing u hydrogen atoms from the aforementioned hydrocarbon group or fluoroalkyl group, etc. may be mentioned.

[0872] R sa The fluoroalkyl group represented by R is preferably saturated and may be linear, branched, or cyclic. As specific examples thereof, groups in which a part or all of the hydrogen atoms of the aforementioned hydrocarbon group are substituted with fluorine atoms may be mentioned. As specific examples thereof, 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. may be mentioned.

[0873] As specific examples of the repeating unit represented by any one of formula (6A) to formula (6E), those shown below may be mentioned, but are not limited thereto. It should be noted that in the following formula, R B is the same as above.

[0874] [Chemical formula 292]

[0875]

[0876] [Chemical formula 293]

[0877]

[0878] [Chemical formula 294]

[0879]

[0880] [Chemical Formula 295]

[0881]

[0882] [Chemical Formula 296]

[0883]

[0884] The aforementioned polymeric surfactant may further contain other repeating units other than the repeating units represented by Formula (6A) to Formula (6E). Specific examples of the other repeating units include repeating units obtained from methacrylic acid, α-trifluoromethyl methacrylic acid derivatives, etc. In the polymeric surfactant, the content of the repeating units represented by Formula (6A) to (6E) is preferably 20 mol% or more, more preferably 60 mol% or more, and still more preferably 100 mol% in all the repeating units.

[0885] The Mw of the aforementioned polymeric surfactant is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. Mw / Mn is preferably 1.0 to 2.0, more preferably 1.0 to 1.6.

[0886] As a method for synthesizing the aforementioned polymeric surfactant, the following method can be cited: A monomer containing an unsaturated group that provides the repeating units represented by Formula (6A) to Formula (6E) and other repeating units as needed is added with a radical initiator in an organic solvent and heated to polymerize it. Specific examples of the organic solvent used during polymerization include: toluene, benzene, THF, diethyl ether, dioxane, etc. Specific examples of the polymerization initiator include: 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 directly use the acid-labile group introduced into the monomer, or can be protected or partially protected after polymerization.

[0887] When synthesizing the aforementioned polymeric surfactant, in order to adjust the molecular weight, existing chain transfer agents such as dodecanethiol and 2-mercaptoethanol can also be used. In this case, the addition amount of these chain transfer agents is preferably 0.01 to 10 mol% relative to the total molar amount of the monomers to be polymerized.

[0888] When the chemically amplified resist composition of the present invention contains (E) a surfactant, its content is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of (A) the base polymer. If the content of (E) the surfactant is 0.1 part by mass or more, the receding contact angle of the resist film surface with water is sufficiently increased. If it is 50 parts by mass or less, the dissolution rate of the resist film surface with respect to the developer is small, and the height of the formed fine pattern is sufficiently maintained. (E) The surfactant can be used alone or in combination of two or more.

[0889] [(F) Dissolution inhibitor]

[0890] The chemically amplified resist composition of the present invention may further contain a dissolution inhibitor as component (F). When the chemically amplified resist composition of the present invention is positive type, by incorporating a dissolution inhibitor, the difference in dissolution rate between the exposed portion and the unexposed portion can be further increased, and the resolution can be further improved.

[0891] Specific examples of the aforementioned dissolution inhibitor include compounds having a molecular weight preferably of 100 to 1000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule, and compounds in which the hydrogen atoms of the phenolic hydroxyl groups are replaced by acid-labile groups in a proportion of 0 to 100 mol% in total, or compounds containing a carboxyl group in the molecule and compounds in which the hydrogen atoms of the carboxyl group are replaced by acid-labile groups in a proportion of 50 to 100 mol% on average in total. Specifically, bisphenol A, triphenol, phenolphthalein, cresol novolac, naphthoic acid, adamantane carboxylic acid, compounds in which the hydrogen atoms of the hydroxyl groups and carboxyl groups of cholic acid are replaced by acid-labile groups, etc. can be mentioned. For example, the compounds described in paragraphs

[0155] to

[0178] of Japanese Patent Application Laid-Open No. 2008-122932 can be mentioned.

[0892] When the chemically amplified resist composition of the present invention contains (F) a dissolution inhibitor, its content is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, relative to 80 parts by mass of (A) the base polymer. (F) The dissolution inhibitor can be used alone or in combination of two or more.

[0893] [(G) Other components]

[0894] The chemically amplified resist composition of the present invention may also contain (G) other components, such as: compounds that decompose by acid and generate acid (acid proliferation compounds), organic acid derivatives, fluoroalcohols, water repellency improvers, etc. As the above-mentioned acid proliferation compounds, reference can be made to the compounds described in JP-A-2009-269953 or JP-A-2010-215608. When containing the aforementioned acid proliferation compound, its content is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass, relative to 80 parts by mass of the (A) base polymer. If the content is too large, it is difficult to control acid diffusion, and sometimes deterioration of resolution and pattern shape may occur. As the above-mentioned organic acid derivatives and fluorosubstituted alcohols, reference can be made to the compounds described in JP-A-2009-269953 or JP-A-2010-215608.

[0895] The aforementioned water repellency improver can be used for immersion lithography without using a top coat. As the aforementioned water repellency improver, polymers containing fluorinated alkyl groups, polymers containing 1,1,1,3,3,3-hexafluoro-2-propanol residues with a specific structure, etc. can be cited. More preferably, the polymers exemplified in JP-A-2007-297590, JP-A-2008-111103, etc. The aforementioned water repellency improver needs to be dissolved in an alkali developer or an organic solvent developer. The above-mentioned water repellency improver having specific 1,1,1,3,3,3-hexafluoro-2-propanol residues has good solubility in the developer. As the water repellency improver, a polymer containing repeating units of amino or amine salts has a high effect of preventing evaporation of acid in PEB and preventing poor opening of the hole pattern after development. When the chemically amplified resist composition of the present invention contains the above-mentioned water repellency improver, its content is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the (A) base polymer.

[0896] [Pattern formation method]

[0897] When the chemically amplified resist composition of the present invention is used for manufacturing various integrated circuits, known lithography methods can be applied. For example, as a pattern formation method, a method including the following steps can be cited: a step of forming a resist film on a substrate using the above-mentioned chemically amplified resist composition; a step of exposing the above-mentioned resist film with high-energy rays; and a step of developing the above-mentioned exposed resist film using a developer.

[0898] First, the chemically amplified resist composition of the present invention is coated on a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflection film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor blade coating, etc., so that the coating thickness becomes 0.01 to 2.0 μm. It is preferably pre-baked on a hot plate at 60 to 150 °C for 10 seconds to 30 minutes, more preferably pre-baked at 80 to 120 °C for 30 seconds to 20 minutes to form a resist film.

[0899] Next, the resist film is exposed using high-energy rays. Examples of the high-energy rays include ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, γ-rays, synchrotron radiation, etc. Examples of the high-energy rays include ultraviolet rays, far ultraviolet rays, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer lasers, γ-rays, synchrotron radiation, etc. When using ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, γ-rays, synchrotron radiation, etc. as the high-energy rays, irradiation is performed directly or using a mask for forming a target pattern so that the exposure dose is preferably 1 to 200 mJ / cm 2 or so, more preferably 10 to 100 mJ / cm 2 or so. In the case of using EB as the high-energy ray, the exposure dose is preferably about 0.1 to 100 μC / cm 2 or so, more preferably 0.5 to 50 μC / cm 2 and the pattern is drawn directly or using a mask for forming a target pattern. The chemically amplified resist composition of the present invention is particularly suitable for fine patterning using ArF excimer laser with a wavelength of 193 nm, KrF excimer laser with a wavelength of 248 nm, EB, or EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, γ-rays, or synchrotron radiation in high-energy rays.

[0900] After exposure, PEB can be performed on a hot plate at preferably 60 to 150 °C for 10 seconds to 30 minutes, more preferably at 80 to 120 °C for 30 seconds to 20 minutes.

[0901] After exposure or PEB, a developer containing an aqueous solution of an alkali such as 0.1 to 10% by mass, preferably 2 to 5% by mass, of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. is used, and development is carried out for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, using a conventional method such as the dip method, puddle method, spray method, etc. Thus, the irradiated part dissolves in the developer, and the unexposed part does not dissolve, forming a target positive pattern on the substrate.

[0902] An organic solvent developer can also be used instead of the above aqueous alkali solution to obtain a negative pattern. Specific examples of the developer used at this time include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents can be used alone or in combination of two or more.

[0903] At the end of development, rinsing can be carried out. As the rinsing liquid, a solvent that is preferably miscible with the developer and does not dissolve the resist film is used. As such a solvent, an alcohol having 3 to 10 carbon atoms, an ether compound having 8 to 12 carbon atoms, an alkane, alkene, alkyne, or aromatic solvent having 6 to 12 carbon atoms is preferably used.

[0904] Specific examples of the alcohol having 3 to 10 carbon atoms include n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentanol, neopentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, etc.

[0905] As specific examples of the ether compound having 8 to 12 carbon atoms, dibutyl ether, diisobutyl ether, di-sec-butyl ether, dipentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, dihexyl ether, etc. can be mentioned.

[0906] As specific examples of the alkane having 6 to 12 carbon atoms, hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. can be mentioned. As specific examples of the alkene having 6 to 12 carbon atoms, hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. can be mentioned. As specific examples of the alkyne having 6 to 12 carbon atoms, hexyne, heptyne, octyne, etc. can be mentioned.

[0907] As specific examples of the aromatic solvent, toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, etc. can be mentioned.

[0908] By performing rinsing, collapse of the resist pattern and generation of defects can be reduced. In addition, rinsing is not necessary, and by not performing rinsing, the amount of solvent used can be reduced.

[0909] The holes or trench patterns can also be shrunk by heat flow, RELACS or DSA. By coating a shrinkage agent on the hole pattern, diffusion of the acidic catalyst from the resist film during baking causes crosslinking of the shrinkage agent on the surface of the resist film, and the shrinkage agent adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180 °C, more preferably 80 to 170 °C, and the baking time is preferably 10 to 300 seconds to remove the excess shrinkage agent and shrink the hole pattern.

[0910] [Examples]

[0911] The present invention will be specifically described below with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples. It should be noted that the apparatuses used are as described above.

[0912] ·MALDITOF-MS: S3000 manufactured by JEOL Ltd.

[0913] [1] Synthesis of onium salt type monomer

[0914] [Example 1-1] Synthesis of onium salt type monomer a-1

[0915] [Chemical formula 297]

[0916]

[0917] (1) Synthesis of intermediate In-1

[0918] Under a nitrogen atmosphere, the raw material SM-1 (37.2 g), triethylamine (18.0 g), and 4-dimethylaminopyridine (1.50 g) were dissolved or suspended in THF (200 g) in a reaction vessel, and the resulting mixture was cooled in an ice bath. Then, a solution obtained by dissolving p-styrenesulfonyl chloride (16.4 g) in THF (50 g) was added dropwise. After the addition was complete, the temperature in the reaction vessel was raised to 50 °C and allowed to age for 6 hours. Then, the reaction solution was cooled, and saturated aqueous sodium bicarbonate solution (100 g) was added to stop the reaction. The target product was extracted twice with ethyl acetate (200 g), subjected to a usual aqueous work-up, the solvent was distilled off, and purification was carried out by silica gel chromatography to obtain 45.8 g of intermediate In-1 in the form of an oil (yield 97%).

[0919] (2) Synthesis of intermediate In-2

[0920] Under a nitrogen atmosphere, intermediate In-1 (45.8 g) was dissolved in THF (200 g). While cooling in an ice bath, 25 mass% aqueous sodium hydroxide solution (15.5 g) was added dropwise. After the addition, the temperature in the reaction vessel was raised to 30 °C and allowed to age for 12 hours. After aging, the reaction solution was cooled, and 20 mass% hydrochloric acid (18.2 g) was added dropwise to stop the reaction. The target product was extracted twice with ethyl acetate (200 g), subjected to a usual aqueous work-up, the solvent was distilled off, and recrystallization was carried out with hexane to obtain 37.5 g of intermediate In-2 in the form of white crystals (yield 90%).

[0921] (3) Synthesis of intermediate In-3

[0922] Under a nitrogen atmosphere, intermediate In-2 (37.5 g), raw material SM-2 (34.8 g), 4-dimethylaminopyridine (1.1 g), and chloromethane (150 g) were added to a reaction vessel, and the mixture was cooled in an ice bath. While maintaining the temperature in the reaction vessel at 20 °C or lower, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (20.1 g) was added in powder form. After the addition, the temperature was raised to room temperature and allowed to age for 12 hours. After aging, water (100 g) was added to stop the reaction, a usual aqueous work-up was carried out, the solvent was distilled off, and diisopropyl ether was added for recrystallization to obtain 61.5 g of intermediate In-3 in the form of an oil (yield 89%).

[0923] (4) Synthesis of the onium salt monomer a-1

[0924] Under a nitrogen atmosphere, the intermediate In-3 (61.5 g), the raw material SM-3 (36.6 g), chloromethane (200 g), and water (150 g) were added to a reaction vessel, and the mixture was stirred for 30 minutes. Then, the organic layer was separated, washed with water, and then concentrated under reduced pressure. The concentrated solution was purified by silica gel chromatography to obtain 71.6 g of the target onium salt monomer a-1 in the form of an oil (yield 87%).

[0925] MALDI TOF-MS: POSITIVE M + 461 (corresponding to C 18 H 10 F4IS + )

[0926] NEGATIVE M - 766 (corresponding to C 18 H 10 F5I2O8S2 - )

[0927] [Example 1-2 to 1-7] Synthesis of onium salt monomers a-2 to a-7

[0928] Using the corresponding raw materials and known organic synthesis reactions, onium salt monomers a-2 to a-7 represented by the following formula were synthesized.

[0929] [Chemical formula 298]

[0930]

[0931] [Comparative Example 1-1 to 1-4] Synthesis of comparative onium salt monomers ca-1 to ca-4

[0932] Using the corresponding raw materials and known organic synthesis reactions, comparative onium salt monomers ca-1 to ca-4 represented by the following formula were synthesized.

[0933] [Chemical formula 299]

[0934]

[0935] [2] Synthesis of basic polymer

[0936] Among the monomers used in the synthesis of the basic polymer, the monomers other than monomers a-1 to a-7 and comparative monomers ca-1 to ca-4 are as described above.

[0937] [Chemical formula 300]

[0938]

[0939] [Chemical formula 301]

[0940]

[0941] [Chemical Formula 302]

[0942]

[0943] [Example 2-1] Synthesis of Polymer P-1

[0944] Under a nitrogen atmosphere, monomer a-1 (53.8 g), monomer b1-1 (35.8 g), monomer c-1 (10.5 g), 3.36 g of V-601 (manufactured by Fuji Photo Film Co., Ltd.) and 139 g of MEK were added to a flask to prepare a monomer-polymerization initiator solution. In another flask under a nitrogen atmosphere, 46 g of MEK was taken and heated to 80 °C with stirring. The above monomer-polymerization initiator was added dropwise over 4 hours. After the addition was completed, stirring was continued for 2 hours while maintaining the temperature of the polymerization solution at 80 °C, and then it was cooled to room temperature. The obtained polymerization solution was added dropwise to 3000 g of vigorously stirred hexane, and the precipitated polymer was separated by filtration. The obtained polymer was washed twice with 600 g of hexane and then dried in vacuo at 50 °C for 20 hours to obtain a white powder polymer P-1 (yield 97.1 g, yield 97%). The Mw of polymer P-1 was 9400, and Mw / Mn was 1.75. It should be noted that Mw is a polystyrene conversion measurement value obtained by GPC using DMF as a solvent.

[0945] [Chemical Formula 303]

[0946]

[0947] [Examples 2-2 to 2-20, Comparative Examples 2-1 to 2-10] Synthesis of Polymers P-2 to P-20, Comparative Polymers CP-1 to CP-10

[0948] Except for changing the types and blending ratios of the respective monomers, the polymers shown in Tables 1 and 2 were produced by the same method as in Example 2-1.

[0949] [Table 1]

[0950]

[0951] [Table 2]

[0952]

[0953] [3] Preparation of Chemically Amplified Resist Composition [Examples 3-1 to 3-20, Comparative Examples 3-1 to 3-10]

[0954] The specified components in the base polymers (P-1 to P-20) of the present invention, comparative base polymers (CP-1 to CP-10), acid generators (PAG-1, PAG-2), and quenchers (SQ-1 to SQ-3, AQ-1) were dissolved in a solvent containing 0.01% by mass of FC-4430 manufactured by 3M Company as a surfactant according to the compositions shown in Tables 3 and 4 below to prepare a solution. The solution was filtered through a 0.2 μm Teflon (registered trademark) type filter to prepare chemically amplified resist compositions (R-1 to R-20, CR-1 to CR-10).

[0955] [Table 3]

[0956]

[0957] [Table 4]

[0958]

[0959]

[0960] In Tables 3 and 4, the solvent, quenchers (SQ-1 to SQ-3, AQ-1), and acid generators (PAG-1, PAG-2) are as described above.

[0961] · Solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0962] DAA (diacetone alcohol)

[0963] · Quenchers: SQ-1 to SQ-3, AQ-1

[0964] [Chemical Formula 304]

[0965]

[0966] · Acid generators: PAG-1, PAG-2

[0967] [Chemical Formula 305]

[0968]

[0969] [4] EUV Lithography Evaluation (1)

[0970] [Examples 4-1 to 4-20, Comparative Examples 4-1 to 4-10]

[0971] Each of the chemically amplified resist compositions (R-1 to R-20, CR-1 to CR-10) shown in Tables 3 and 4 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and pre-baked at 100 °C for 60 seconds using a hot plate to fabricate a resist film with a film thickness of 50 nm. For the aforementioned resist film, using an EUV scanner NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination) manufactured by ASML, for the exposure of an LS pattern with a size of 18 nm and a pitch of 36 nm on the wafer, while changing the exposure dose and focus (exposure dose interval: 1 mJ / cm 2 , focus interval: 0.020 μm), after exposure, PEB was performed for 60 seconds at the temperatures shown in Tables 5 and 6. Then, development was carried out by standing for 30 seconds with a 2.38 mass% TMAH aqueous solution, rinsing was performed with a rinsing material containing a surfactant, and spin drying was carried out to obtain a positive pattern.

[0972] The obtained LS pattern was observed with a length measuring SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, and the sensitivity, EL, LWR, DOF, and collapse limit were evaluated according to the following methods. The results are shown in Tables 5 and 6.

[0973] [Sensitivity Evaluation]

[0974] The optimum exposure dose Eop (mJ / cm 2 ) at which an LS pattern with a line width of 18 nm and a pitch of 36 nm can be obtained was determined, and this was taken as the sensitivity. The smaller this value, the higher the sensitivity.

[0975] [EL Evaluation]

[0976] Based on the exposure doses formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm spacing width in the above LS pattern, EL (unit: %) was calculated by the following formula. The larger this value, the better the performance.

[0977] EL (%) = (E1 - E2 / Eop) × 100

[0978] E1: The optimum exposure dose that provides an LS pattern with a line width of 16.2 nm and a pitch of 36 nm

[0979] E2: The optimum exposure dose that provides an LS pattern with a line width of 19.8 nm and a pitch of 36 nm

[0980] Eop: The optimum exposure dose that provides an LS pattern with a line width of 18 nm and a pitch of 36 nm

[0981] [LWR Evaluation]

[0982] For the LS pattern obtained by irradiating with Eop, measure the sizes at 10 positions in the length direction of the line, and obtain three times the standard deviation (σ) (3σ) as the LWR from the results. The smaller this value, the smaller the roughness and the more uniform the line width of the pattern can be obtained.

[0983] [DOF evaluation]

[0984] As the depth of focus evaluation, obtain the focusing range formed within the range of ±10% (16.2 to 19.8 nm) of the size of 18 nm in the above LS pattern. The larger this value, the wider the depth of focus.

[0985] [Evaluation of the collapse limit of the line pattern]

[0986] Measure the line sizes of each exposure amount at the best focus of the above LS pattern at 10 positions in the length direction. Take the thinnest line size that does not collapse as the collapse limit size. The smaller this value, the better the collapse limit.

[0987] [Table 5]

[0988]

[0989] [Table 6]

[0990]

[0991] From the results shown in Tables 5 and 6, it can be seen that the chemically amplified resist composition using the base polymer containing the repeating unit of the onium salt type monomer of the present invention has excellent EL, LWR, and DOF under good sensitivity. In addition, it was confirmed that the value of the collapse limit is small and it is also resistant to pattern collapse in fine pattern formation. Therefore, the chemically amplified resist composition of the present invention is shown to be suitable as a material for EUV lithography.

[0992] [5] EUV lithography evaluation (2)

[0993] [Examples 5-1 to 5-20, Comparative Examples 5-1 to 5-10]

[0994] Each of the chemically amplified resist compositions (R-1 to R-20, CR-1 to CR-10) shown in Tables 3 and 4 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and pre-baked at 105 °C for 60 seconds using a hot plate to produce a resist film with a film thickness of 50 nm. It was exposed using an EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask with a hole pattern having a pitch of 46 nm and a +20% deviation in size on the wafer) manufactured by ASML, and PEB was performed at the temperatures described in Tables 7 and 8 for 60 seconds using a hot plate, and developed for 30 seconds with a 2.38 mass% TMAH aqueous solution to form a hole pattern with a size of 23 nm.

[0995] Using a length-measuring SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, the exposure dose when forming holes with a size of 23 nm was measured and used as the sensitivity. In addition, the sizes of 50 holes at this time were measured, and three times the standard deviation (σ) calculated from the results (3σ) was used as the size deviation (CDU). The results are shown in Tables 7 and 8.

[0996] [Table 7]

[0997]

[0998] [Table 8]

[0999]

[1000] From the results shown in Tables 7 and 8, it was confirmed that the chemically amplified resist composition of the present invention has good sensitivity and excellent CDU.

[1001] [6] Dry etching resistance evaluation

[1002] [Examples 6-1 to 6-20, Comparative Examples 6-1 to 6-10]

[1003] 2 g of each of the polymers (polymers P-1 to P-20, comparative polymers CP-1 to CP-10) shown in Tables 1 and 2 was dissolved in 10 g of cyclohexanone, filtered through a 0.2 μm-sized filter, and the resulting polymer solution was formed into a film on a Si substrate by spin coating to produce a film with a thickness of 300 nm, and evaluated under the following conditions.

[1004] Etching test in CHF3 / CF4-based gas:

[1005] Using a dry etching apparatus TE-8500P manufactured by Tokyo Electron Limited, the film thickness difference of the polymer film before and after etching was determined.

[1006] The etching conditions are as described above.

[1007]

[1008] In this evaluation, a case with a small film thickness difference, that is, a small reduction amount, indicates high etching resistance.

[1009] The results of the dry etching resistance are shown in Tables 9 and 10.

[1010] [Table 9]

[1011]

[1012]

[1013] [Table 10]

[1014] Polymer <![CDATA[Etching rate of CHF3 / CF4-based gas (nm / min)]]> Comparative Example 6-1 CP-1 109 Comparative Example 6-2 CP-2 101 Comparative Example 6-3 CP-3 103 Comparative Example 6-4 CP-4 100 Comparative Example 6-5 CP-5 110 Comparative Example 6-6 CP-6 102 Comparative Example 6-7 CP-7 101 Comparative Example 6-8 CP-8 103 Comparative Example 6-9 CP-9 104 Comparative Example 6-10 CP-10 103

[1015] It was confirmed from the results shown in Tables 9 and 10 that the polymer of the present invention has excellent dry etching resistance to CHF3 / CF4-based gases.

Claims

1. An onium salt type monomer, which is composed of an anion represented by the following formula (a1) and a cation represented by the following formula (a2). In the formula, n1 is 0 or 1, n2 is 0 or 1, n3 is an integer from 0 to 4, n4 is an integer from 0 to 4, n5 is an integer from 1 to 6. However, when n2 is 0, 1 ≤ n4 + n5 ≤ 4; when n2 is 1, 1 ≤ n4 + n5 ≤ 6. n6 is an integer from 0 to 4, n7 is 0 or 1, n8 is 0 or 1. However, n7 and n8 are not 0 at the same time. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R 1 is a halogen, nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain heteroatoms, or a hydrocarbon thio group having 1 to 20 carbon atoms which may contain heteroatoms. When n3 is 2, 3 or 4 and n7 is 1, each R 1 may be the same or different from each other. Multiple Rs 1 may be bonded to each other and together with the carbon atoms to which they are bonded form a ring. When n8 is 0, n7 is 1 and n3 is 1, 2, 3 or 4, and at least one R 1 is an iodine atom. R 2 is a halogen atom other than an iodine atom, a nitro group, a C1-C20 hydrocarbon group which may contain a heteroatom, a C1-C20 hydrocarbon oxy group which may contain a heteroatom, or a C1-C20 hydrocarbon thio group which may contain a heteroatom. When n4 is 2, 3 or 4 and n8 is 1, each R 2 may be the same or different from each other, and multiple R 2 may be bonded to each other and together with the carbon atoms to which they are bonded form a ring, L A1 , L B1 and L C each independently represents a single bond, an ether bond, an ester bond, a sulfonate bond, an amide bond, a sulfonamide bond, a carbonate bond or a carbamate bond. X L1 is a single bond or an alkylene group having 1 to 40 carbon atoms which may also contain heteroatoms. Q 1 and Q 2 each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, Q 3 and Q 4 each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, In the formula, m1 is 0 or 1, m2 is 0 or 1, m3 is 0 or 1, m4 is an integer from 0 to 4, m5 is an integer from 0 to 4, m6 is an integer from 0 to 6, m7 is an integer from 0 to 6, m8 is an integer from 0 to 2, m9 is an integer from 0 to 2, m10 is an integer from 0 to 2, m11 is 0 or 1, m12 is an integer from 0 to 4, m13 is an integer from 0 to 2, m14 is an integer from 0 to 2. However, when m1 is 0, 0 ≤ m6 + m9 ≤ 4; when m1 is 1, 0 ≤ m6 + m9 ≤ 6. When m2 is 0, 0 ≤ m7 + m10 ≤ 4; when m2 is 1, 0 ≤ m7 + m10 ≤ 6. When m3 is 0, 1 ≤ m4 + m5 + m8 + m14 ≤ 4; when m3 is 1, 1 ≤ m4 + m5 + m8 + m14 ≤ 6. When m1 is 0, 0 ≤ m12 + m13 ≤ 4; when m11 is 1, 0 ≤ m12 + m13 ≤ 6. Also, m4 + m12 ≥ 1. R F1 ~R F3 Each independently represents a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbon oxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbon thio group having 1 to 6 carbon atoms. When m6 is 2 or more, each R F1 may be the same as or different from each other. When m7 is 2 or more, each R F2 may be the same as or different from each other. When m5 is 2 or more, each R F3 may be the same as or different from each other. R 3 ~R 6 is a halogen atom other than an iodine atom and a fluorine atom, a nitro group, a nitrile group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbon thio group having 1 to 20 carbon atoms which may contain a heteroatom. When m8 is 2, the two Rs 3 may be the same as or different from each other, and the two Rs 3 may be bonded to each other and together with the carbon atom to which they are bonded form a ring. When m9 is 2, the two Rs 4 may be the same as or different from each other, and the two Rs 4 may be bonded to each other and together with the carbon atom to which they are bonded form a ring. When m10 is 2, the two Rs 5 may be the same as or different from each other, and the two Rs 5 may be bonded to each other and together with the carbon atom to which they are bonded form a ring. When m13 is 2, the two Rs 6 may be the same as or different from each other, and the two Rs 6 may be bonded to each other and together with the carbon atom to which they are bonded form a ring. In addition, the aromatic rings directly bonded to the sulfur cation in the sulfonium cation can be bonded to each other and to sulfur + to form a ring together + ​ L A2 and L B2 each independently represents a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond, X L2 is a single bond or an alkylene group having 1 to 40 carbon atoms which may also contain a heteroatom.

2. The onium salt type monomer according to claim 1, wherein, The anion is represented by the following formula (a1-1): In the formula, n1 to n6, R A 、R 1 、R 2 、L A1 、L C and Q 1 ~Q 4 are the same as those above.

3. The onium salt type monomer according to claim 2, wherein, The anion is represented by the following formula (a1-2): where n1 to n6, R A , R 1 , R 2 , L A1 and Q 1 to Q 4 are the same as above.

4. The onium salt monomer according to claim 1, wherein The cation is represented by the following formula (a2-1): Wherein, m4 to m10, m12 to m14, R F1 ~R F3 、R 3 ~R 6 、L A2 、L B2 and X L2 are the same as those described above.

5. The onium salt monomer according to claim 4, wherein The cation is represented by the following formula (a2-2): where m4 to m10, R F1 ~R F3 and R 3 ~R 5 are the same as above.

6. A monomeric photoacid generator, which is composed of the onium salt type monomer according to any one of claims 1 to 5.

7. A polymer, which contains repeating units derived from the monomeric photoacid generator according to claim 6.

8. The polymer according to claim 7, which further contains repeating units represented by the following formula (b1) or (b2). wherein, R A each independently represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X 1 represents a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-X 11 - or *-C(=O)-NH-X 11 -, the phenylene group or naphthylene group may be substituted by a hydroxyl group, a nitro group, a cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom, X 11 is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH- * represents an atomic bond with a carbon atom of the main chain. R 11 is a halogen atom, a cyano group, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon group carbonyl having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon group carbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbon oxy group carbonyl having 2 to 20 carbon atoms which may contain a heteroatom. AL 1 and AL 2 each independently represents an acid-labile group, a is an integer from 0 to 4.

9. The polymer according to claim 7, which further contains repeating units represented by the following formula (b3). In the formula, b1 is 0 or 1, b2 is an integer from 0 to 3 when b1 is 0, and b2 is an integer from 0 to 5 when b1 is 1. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X 3 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * represents the atomic bond with the carbon atom of the main chain. R 12 and R 13 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. Further, R 12 and R 13 may be bonded to each other and together with the carbon atoms to which they are bonded form a ring, R 14 represents a halogen atom, a hydroxyl group, a cyano group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon thio group having 1 to 20 carbon atoms which may contain a heteroatom, or -N(R 14A )(R 14B ), where R 14A and R 14B are each independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, and when b2 is 2 or more, a plurality of R 14 may be bonded to each other and together with the carbon atoms of the aromatic ring to which they are bonded form a ring. X 4 is a single bond, an aliphatic alkylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining them. X 5 and X 6 each independently represents an oxygen atom or a sulfur atom, provided that X 4 and X 6 are bonded to adjacent carbon atoms of the aromatic ring.

10. The polymer according to claim 7, which further contains repeating units represented by the following formula (c1). wherein, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, where * represents the atomic bond with the carbon atom of the main chain R 21 is a halogen atom, nitro group, cyano group, carboxyl group, hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, hydrocarbon group carbonyl having 2 to 20 carbon atoms which may contain a heteroatom, hydrocarbon group carbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or hydrocarbon oxy group carbonyl having 2 to 20 carbon atoms which may contain a heteroatom. c is an integer from 1 to 4, d is an integer from 0 to 3. However, 1 ≤ c + d ≤ 5.

11. The polymer according to claim 7, which further contains repeating units represented by the following formula (d1). wherein, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, Z 1 is a single bond, phenylene, naphthylene, *-C(=O)-O-Z 11 - or *-C(=O)-NH-Z 11 -, the phenylene or naphthylene may be substituted by a hydroxyl group, nitro group, cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom or a halogen atom, * represents an atomic bond with a carbon atom of the main chain, Z 11 is a saturated alkylene group having 1 to 10 carbon atoms, phenylene or naphthylene, and the saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring R 31 is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one or more structures selected from hydroxyl groups other than phenolic hydroxyl groups, cyano groups, carbonyl groups, carboxyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, and carboxylic anhydrides (-C(=O)-O-C(=O)-).

12. A chemically amplified resist composition, which contains (A) a base polymer containing the polymer according to claim 7.

13. The chemically amplified resist composition according to claim 12, which further contains (B) an organic solvent.

14. The chemically amplified resist composition according to claim 12, which further contains (C) a quencher.

15. The chemically amplified resist composition according to claim 12, which further contains (D) an acid generator.

16. The chemically amplified resist composition according to claim 12 further comprises (E) a surfactant.

17. The chemically amplified resist composition according to claim 12 further comprises (F) a dissolution inhibitor.

18. A pattern forming method comprising the following steps: forming a resist film on a substrate using the chemically amplified resist composition according to claim 12; exposing the resist film to high energy rays; and developing the exposed resist film using a developer.

19. The pattern forming method according to claim 18, wherein, The high energy rays are an ArF excimer laser with a wavelength of 193 nm, a KrF excimer laser with a wavelength of 248 nm, an electron beam, or extreme ultraviolet rays with a wavelength of 3 to 15 nm.

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