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: an onium salt-type monomer which has excellent solvent solubility in lithography using high-energy rays, and which is capable of forming a pattern by using the onium salt-type monomer, 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 forming a pattern by using the chemically amplified resist composition; the photosensitive resin composition has excellent lithography properties such as high sensitivity, high contrast, EL, LWR, CDU, and DOF, is less susceptible to pattern collapse during the formation of fine patterns, and has excellent etching resistance. The onium salt type monomer is represented by formula (a).

Description

Technical Field

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

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern rules is progressing rapidly. In particular, the expansion of the flash memory market and the increase in memory capacity have driven miniaturization. As the most advanced miniaturization method, ArF lithography is being used to mass-produce 65nm node devices, and preparations are underway for mass production of 45nm node devices using next-generation ArF immersion lithography. As candidates for the next-generation 32nm node device, immersion lithography using a combination of a liquid with a higher refractive index than water, a high-refractive-index lens, and an ultra-high-NA lens with a high-refractive-index resist film, extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm, and double exposure (double patterning lithography) of ArF lithography are being studied.

[0003] As miniaturization progresses, the contrast of light decreases as the diffraction limit of light is approached. This decrease in contrast leads to a decrease in the resolution of hole patterns and groove patterns and a decrease in focus margin in the positive resist film.

[0004] As patterns become increasingly miniaturized, the line width roughness (LWR) of line patterns and the dimensional uniformity (CDU) of hole patterns have become increasingly problematic. Some have pointed to the uneven distribution of base polymers and acid generators, the effects of aggregation, and the effects of acid diffusion. Furthermore, as resist films become thinner, the LWR tends to increase, and the degradation of LWR caused by the thinning associated with miniaturization has become a serious problem.

[0005] In resist compositions for EUV lithography, high sensitivity, high resolution, and low LWR must be simultaneously achieved. Shortening the acid diffusion distance reduces the LWR, but also reduces sensitivity. For example, lowering the post-exposure bake (PEB) temperature reduces the LWR, but also reduces sensitivity. Increasing the amount of quencher also reduces the LWR, but also reduces sensitivity. There is a need to break the trade-off between sensitivity and LWR.

[0006] In order to suppress the diffusion of acid, a resist composition containing repeating units of an onium salt of a sulfonic acid having a polymerizable unsaturated bond has been proposed (Patent Document 1). This so-called polymer-bonded acid generator has the characteristic of very short acid diffusion because it generates polymer-type sulfonic acid by exposure. In addition, by increasing the ratio of the acid generator, the sensitivity can also be improved. Additive-type acid generators also become highly sensitive when the addition amount 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 the balance between sensitivity, LWR and CDU, it can be said that polymer-type acid generators have high capabilities.

[0007] Iodine atoms have a very strong absorption in EUV at a wavelength of 13.5 nm. The effect of generating secondary electrons from iodine atoms during exposure has been confirmed, and this has attracted attention in EUV lithography. Patent Document 2 describes a photoacid generator in which an iodine atom is introduced into an anion. In addition, Patent Document 3 describes a photoacid generator containing a polymerizable group in which an iodine atom is introduced into an anion. Therefore, although improvements in lithographic performance have been confirmed to a certain extent, the solubility of iodine atoms in organic solvents is not high, and there is concern about precipitation in the solvent.

[0008] Furthermore, in recent years, fluoroalkanesulfonic acid, an organic fluorine compound that is a target of PFAS, has been regulated, raising concerns about its impact on the environment and human health. In addition to the demand for further miniaturization, there is also a desire to develop resist materials with less environmental impact.

[0009] Prior art literature

[0010] Patent Literature

[0011] [Patent Document 1] Japanese Patent No. 4425776

[0012] [Patent Document 2] Japanese Patent No. 6720926

[0013] [Patent Document 3] Japanese Patent No. 6973274 Summary of the Invention

[0014] [Problems to be Solved by the Invention]

[0015] In chemically amplified resist compositions using an acid as a catalyst, there is a demand for development of a resist composition that has higher sensitivity, can improve the LWR of a line pattern and the CDU of a hole pattern, and also has excellent etching resistance after pattern formation.

[0016] The present invention has been made in view of the above-mentioned circumstances, and its object is to provide an onium salt-type monomer; a polymer comprising repeating units derived from the onium salt-type monomer; a chemically amplified resist composition comprising the polymer; and a pattern forming method using the chemically amplified resist composition. The onium salt-type monomer has excellent solvent solubility, high sensitivity, high contrast, and excellent lithographic performance such as exposure margin (EL), LWR, CDU, and depth of focus (DOF), particularly in lithography using high-energy radiation such as KrF excimer lasers, ArF excimer lasers, electron beams (EB), and EUV. Furthermore, the monomer is less likely to cause pattern collapse in fine pattern formation and has excellent etching resistance.

[0017] [Means for solving the problem]

[0018] The present inventors have conducted intensive studies to achieve the above-mentioned objectives and have discovered that a chemically amplified resist composition having high sensitivity, improved LWR and CDU, high contrast and resolution, and excellent etching resistance can be obtained by using a polymer containing repeating units of a sulfonium salt or iodonium salt derived from an aromatic sulfonic acid anion having a polymerizable group having a styrene or vinylnaphthalene structure and containing an aromatic ring structure substituted with an iodine atom as a polymer-bound acid generator. This has led to the completion of the present invention.

[0019] That is, the present invention provides the following onium salt-type monomers, polymers, chemically amplified resist compositions, and pattern formation methods.

[0020] 1. An onium salt-type monomer represented by the following formula (a):

[0021] [Chemistry 1]

[0022]

[0023] In the formula, n1 is 0 or 1, n2 is an integer from 0 to 4, n3 is 0 or 1, n4 is an integer from 1 to 4, n5 is an integer from 0 to 4, but when n3 is 0, 1≤n4+n5≤4, when n3 is 1, 1≤n4+n5≤6, n6 is 0 or 1, n7 is an integer from 0 to 4, n8 is an integer from 0 to 4, but when n6 is 0, 0≤n7+n8≤4, when n6 is 1, 0≤n7+n8≤6,

[0024] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0025] R 1 is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, and when n2 is 2, 3 or 4, multiple R 1 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring,

[0026] R2 is a halogen atom other than an iodine atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when n5 is 2, 3 or 4, multiple R 2 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring,

[0027] R 3 is a halogen atom other than a fluorine atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when n8 is 2, 3 or 4, multiple R 3 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring,

[0028] R F is 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, and when n7 is 2, 3 or 4, each R F They can be the same or different from each other.

[0029] L A 、L B , and L C 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,

[0030] X L is a single bond or a alkylene group having 1 to 40 carbon atoms which may contain a heteroatom,

[0031] Z + Onium cation.

[0032] 2. The onium salt monomer of 1 is represented by the following formula (a1):

[0033] [Chemistry 2]

[0034]

[0035] Where, n1~n8, R A 、R 1 、R 2 、R 3 、R F 、L A 、L C and Z + Same as above.

[0036] 3. The onium salt monomer as described in 2. is represented by the following formula (a2):

[0037] [Chemistry 3]

[0038]

[0039] Where, n1~n5, R A 、R1 、R 2 、L A 、L C and Z + Same as above.

[0040] 4. The onium salt-type monomer according to any one of 1. to 3., wherein Z + is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2),

[0041] [Chemistry 4]

[0042]

[0043] Where R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom, and R ct1 and R ct2 They may be bonded to each other and to the sulfur atom to which they are bonded to form a ring.

[0044] 5. A polymer comprising a repeating unit derived from the onium salt-type monomer according to any one of 1. to 4.

[0045] 6. The polymer according to 5., which functions as a polymer-bound acid generator.

[0046] 7. The polymer according to 5. or 6., further comprising a repeating unit represented by the following formula (b1) or (b2),

[0047] [Chemistry 5]

[0048]

[0049] Where R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0050] X 1 represents a single bond, phenylene, naphthylene, *-C(=O)-OX 11 - or *-C(=O)-NH-X 11 -, the phenylene or naphthylene group may be substituted by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group having 1 to 10 carbon atoms which may contain a fluorine atom, 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, wherein the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring,

[0051] X 2is a single bond, *-C(=O)-O- or *-C(=O)-NH-,

[0052] * indicates atomic bonds to carbon atoms of the main chain,

[0053] 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 hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom,

[0054] AL 1 and AL 2 are each independently an acid-labile group,

[0055] a is an integer from 0 to 4.

[0056] 8. The polymer according to any one of 5. to 7., further comprising a repeating unit represented by the following formula (b3),

[0057] [Chemistry 6]

[0058]

[0059] In the formula, b1 is 0 or 1, b2 is an integer from 0 to 3 when b1 is 0, and an integer from 0 to 5 when b1 is 1,

[0060] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0061] X 3 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * represents an atomic bond to a carbon atom of the main chain,

[0062] 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 hetero atom, and R 12 and R 13 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring,

[0063] R 14 is 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 hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonthio group having 1 to 20 carbon atoms which may contain a hetero atom, or -N(R 14A )(R 14B ), R 14A and R 14BEach independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. When b2 is 2 or more, multiple R 14 can be bonded to each other and to the carbon atoms of the aromatic ring to which they are bonded to form a ring,

[0064] 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 these groups,

[0065] X 5 and X 6 are each independently an oxygen atom or a sulfur atom, but X 4 and X 6 Bonded to adjacent carbon atoms of the aromatic ring.

[0066] 9. The polymer according to any one of 5. to 8., further comprising a repeating unit represented by the following formula (c1),

[0067] [Chemistry 7]

[0068]

[0069] Where R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0070] Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * represents an atomic bond to a carbon atom of the main chain,

[0071] R 21 is a halogen atom, a nitro group, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom,

[0072] c is an integer of 1 to 4, d is an integer of 0 to 3, but 1≤c+d≤5.

[0073] 10. The polymer according to any one of 5. to 9., further comprising a repeating unit represented by the following formula (d1),

[0074] [Chemistry 8]

[0075]

[0076] Where R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0077] Z 1 represents a single bond, phenylene, naphthylene, *-C(=O)-OZ11 - or *-C(=O)-NH-Z 11 -, the phenylene or naphthylene group may be substituted by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group having 1 to 10 carbon atoms which may contain fluorine atoms, an alkoxy group having 1 to 10 carbon atoms which may contain fluorine atoms, or a halogen atom, * represents an atomic bond to 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, wherein the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring,

[0078] R 31 A group having 1 to 20 carbon atoms, or a hydrogen atom, or a group containing at least one structure selected from the group consisting of a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-).

[0079] 11. A chemically amplified resist composition comprising (A) a base polymer comprising the polymer according to any one of 5. to 10.

[0080] 12. The chemically amplified resist composition according to 11. further comprising (B) an organic solvent.

[0081] 13. The chemically amplified resist composition according to 11. or 12., further comprising (C) a quencher.

[0082] 14. The chemically amplified resist composition according to any one of 11. to 13., further comprising (D) another acid generator.

[0083] 15. The chemically amplified resist composition according to any one of 11. to 14., further comprising (E) a surfactant.

[0084] 16. The chemically amplified resist composition according to any one of 11. to 15., further comprising (F) a dissolution inhibitor.

[0085] 17. A pattern forming method comprising the following steps: forming a resist film on a substrate using the chemically amplified resist composition according to any one of 11. to 16.; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

[0086] 18. The pattern forming method according to 17., wherein the high-energy ray is an ArF excimer laser with a wavelength of 193 nm, a KrF excimer laser with a wavelength of 248 nm, an electron beam, or an extreme ultraviolet ray with a wavelength of 3 to 15 nm.

[0087] [Effects of the Invention]

[0088] The resist film containing a polymer of repeating units derived from an onium salt-type monomer represented by (a) has good solvent solubility and is characterized by low acid diffusion due to the large atomic weight of the iodine atom. This prevents the reduction in resolution caused by blurring due to acid diffusion, and improves LWR and CDU. In addition, the iodine atom group has a very large absorption of EUV at a wavelength of 13.5nm, so secondary electrons are generated from the iodine atom during exposure, resulting in high sensitivity. This makes it possible to construct a chemically amplified resist composition with high sensitivity and improved LWR and CDU. In addition, the aromatic ring acts as a good etching resistance group and is suitable for fine pattern formation. DETAILED DESCRIPTION

[0089] [Onium salt type monomer]

[0090] The onium salt-type monomer of the present invention is represented by the following formula (a).

[0091] [Chemistry 9]

[0092]

[0093] In formula (a), n1 is 0 or 1. When n1 is 0, it is a benzene ring, and when n1 is 1, it is a naphthalene ring. From the perspective of solvent solubility, a benzene ring in which n1 is 0 is preferred. n2 is an integer of 0 to 4. From the perspective of raw material supply, n2 is preferably 0, 1 or 2, and more preferably 0 or 1.

[0094] In formula (a), n3 is 0 or 1. When n3 is 0, it is a benzene ring, and when n3 is 1, it is a naphthalene ring. However, from the viewpoint of solvent solubility, a benzene ring in which n3 is 0 is preferred. n4 is an integer of 1 to 4. The more iodine atoms there are in the anion structure, the higher the absorption to EUV, in particular. However, there is a possibility that the solvent solubility becomes poor and the material precipitates in the resist composition. Therefore, n4 is preferably 1, 2 or 3, more preferably 1 or 2. n5 is an integer of 0 to 4, preferably 0, 1 or 2, more preferably 0 or 1. When n3 is 0, 1≤n4+n5≤4, and when n3 is 1, 1≤n4+n5≤6.

[0095] In formula (a), n6 is 0 or 1. When n6 is 0, it is a benzene ring, and when n6 is 1, it is a naphthalene ring. However, from the perspective of solvent solubility, n6 is preferably a benzene ring. n7 is an integer from 0 to 4, and from the perspective of the acid strength of the generated acid, it is preferably 1, 2, 3, or 4, and more preferably 2, 3, or 4. n8 is an integer from 0 to 4. However, when n6 is 0, 0 ≤ n7 + n8 ≤ 4, and when n6 is 1, 0 ≤ n7 + n8 ≤ 6.

[0096] In formula (a), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0097] In formula (a), at least one iodine atom in the aromatic ring of the anion is bonded to L B The ortho position of the carbon atom to which the polymerizing group is bonded is preferred. Since the iodine atom is an element with a large atomic radius, the rotation of the bond axis between the aromatic ring to which the polymerizable group is bonded and the aromatic ring to which the iodine atom is bonded is suppressed, thereby improving the rigidity of the polymer.

[0098] In formula (a), R 1 is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and more preferably a fluorine atom or an iodine atom. The 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, and eicosyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 6 to 20 carbon atoms, such as vinyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 2 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these. In addition, part or all of the hydrogen atoms of the above hydrocarbon groups 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 groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, the hydrocarbon groups may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, and the like. When n2 is 2, 3, or 4, each R 1 They can be the same or different from each other.

[0099] In addition, when n2 is 2, 3 or 4, multiple R 1They can bond to each other and form a ring together with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. In addition, some or all of the hydrogen atoms in the above-mentioned rings may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a portion of the -CH2- in the above-mentioned rings may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, the rings may also contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), and haloalkyl groups.

[0100] In formula (a), R 2 is a halogen atom other than iodine or a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms. Specific examples of the above-mentioned halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, etc. The above-mentioned hydrocarbon group may be saturated or unsaturated, and may be straight chain, branched chain, or cyclic. Specific examples thereof include and 1 The groups exemplified for the hydrocarbon groups represented are the same groups, but are not limited thereto. When n5 is 2, 3 or 4, each R 2 They can be the same or different from each other.

[0101] In addition, when n5 is 2, 3 or 4, multiple R 2 They may be bonded to each other and form a ring together with the carbon atoms to which they are bonded. The above-mentioned ring is preferably a 5- to 8-membered ring.

[0102] In formula (a), R 3 is a halogen atom other than a fluorine atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of the halogen atom other than a fluorine atom include a chlorine atom, a bromine atom, and an iodine atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include: 1 The same groups as those exemplified for the hydrocarbon groups represented are not limited thereto. When n8 is 2, 3 or 4, each R 3 They can be the same or different from each other.

[0103] In addition, when n8 is 2, 3 or 4, multiple R 3 They may be bonded to each other and form a ring together with the carbon atoms to which they are bonded. The above-mentioned ring is preferably a 5- to 8-membered ring.

[0104] In formula (a), R FEach independently represents a fluorine atom, a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbonoxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbonthio group having 1 to 6 carbon atoms. Among these, a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group, or a trifluoromethylthio group is preferred, and a fluorine atom is more preferred. When n7 is 2, 3, or 4, each R F They can be the same or different from each other.

[0105] In formula (a), L A 、L B and L C 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. A , preferably a single bond, an ether bond, an ester bond or a sulfonate bond, more preferably an ester bond or a sulfonate bond. B Preferably it is a single bond, an ether bond or an ester bond, more preferably a single bond. C , preferably a single bond, an ether bond, an ester bond, an amide bond or a sulfonate bond, more preferably an ether bond, an ester bond or an amide bond.

[0106] In formula (a), X L is a single bond or a carbon number 1 to 40 alkylene group which may contain a hetero atom. From the viewpoint of rigidity, X L Preferably, it is a single bond. In addition, the aforementioned alkylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl, cyclic saturated alkylene, and arylene groups. Examples of the aforementioned heteroatoms include oxygen atoms, nitrogen atoms, and sulfur atoms.

[0107] X L Specific examples of the alkylene group having 1 to 40 carbon atoms which may contain a hetero atom include the following, but are not limited thereto. In the following formulae, * represents L A and L B atomic bonds.

[0108] [Chemistry 10]

[0109]

[0110] [Chemistry 11]

[0111]

[0112] [Chemistry 12]

[0113]

[0114] [Chemistry 13]

[0115]

[0116] Among them, X L -0~X L -22, X L -29~X L -34 and X L -47~X L -58 is better.

[0117] Examples of the onium salt-type monomer represented by formula (a) include groups represented by the following formula (a1).

[0118] [Chemistry 14]

[0119]

[0120] Where, n1~n8, R A 、R 1 、R 2 、R 3 、R F 、L A 、L C and Z + Same as above.

[0121] Examples of the onium salt-type monomer represented by formula (a1) include groups represented by the following formula (a2).

[0122] [Chemistry 15]

[0123]

[0124] Where, n1~n5, R A 、R 1 、R 2 、L A 、L C and Z + Same as above.

[0125] Specific examples of anions of the onium salt represented by formula (a) include the following anions, but are not limited thereto. A As described above, Me is a methyl group. In addition, the bonding positions of the various substituents on the aromatic ring may be interchangeable.

[0126] [Chemistry 16]

[0127]

[0128] [Chemistry 17]

[0129]

[0130] [Chemistry 18]

[0131]

[0132] [Chemistry 19]

[0133]

[0134] [Chemistry 20]

[0135]

[0136] [Chemistry 21]

[0137]

[0138] [Chemistry 22]

[0139]

[0140] [Chemistry 23]

[0141]

[0142] [Chemistry 24]

[0143]

[0144] [Chemistry 25]

[0145]

[0146] [Chemistry 26]

[0147]

[0148] [Chemistry 27]

[0149]

[0150] [Chemistry 28]

[0151]

[0152] [Chemistry 29]

[0153]

[0154] [Chemistry 30]

[0155]

[0156] [Chemistry 31]

[0157]

[0158] [Chemistry 32]

[0159]

[0160] [Chemistry 33]

[0161]

[0162] [Chemistry 34]

[0163]

[0164] [Chemistry 35]

[0165]

[0166] [Chemistry 36]

[0167]

[0168] [Chemistry 37]

[0169]

[0170] [Chemistry 38]

[0171]

[0172] [Chemistry 39]

[0173]

[0174] [Chemistry 40]

[0175]

[0176] [Chemistry 41]

[0177]

[0178] [Chemistry 42]

[0179]

[0180] [Chemistry 43]

[0181]

[0182] [Chemistry 44]

[0183]

[0184] [Chemistry 45]

[0185]

[0186] [Chemistry 46]

[0187]

[0188] [Chemistry 47]

[0189]

[0190] [Chemistry 48]

[0191]

[0192] [Chemistry 49]

[0193]

[0194] [Chemistry 50]

[0195]

[0196] [Chemistry 51]

[0197]

[0198] [Chemistry 52]

[0199]

[0200] [Chemistry 53]

[0201]

[0202] [Chemistry 54]

[0203]

[0204] [Chemistry 55]

[0205]

[0206] [Chemistry 56]

[0207]

[0208] [Chemistry 57]

[0209]

[0210] [Chemistry 58]

[0211]

[0212] [Chemistry 59]

[0213]

[0214] [Chemistry 60]

[0215]

[0216] [Chemistry 61]

[0217]

[0218] In formula (a), Z + The onium cation is preferably a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2).

[0219] [Chemistry 62]

[0220]

[0221] In formula (cation-1) and (cation-2), R ct1 ~R ct5 Each is independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom.

[0222] R ct1 ~R ct5 Specific examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.

[0223] R ct1 ~R ct5 The hydrocarbon group represented by may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 30 carbon atoms, such as vinyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 30 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 30 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and combinations thereof. Aryl groups are preferred. In addition, a part or all of the hydrogen atoms of the above-mentioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of the -CH2- of the above-mentioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, the hydrocarbon group may also 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)-OC(=O)-), a haloalkyl group, and the like.

[0224] In addition, R ct1 and R ct2 They may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, specific examples of the ring structure include the structure represented by the following formula.

[0225] [Chemistry 63]

[0226]

[0227] Wherein, the dotted line represents and R ct3 atomic bonds.

[0228] Specific examples of the sulfonium cation represented by formula (cation-1) include those shown below, but are not limited to these.

[0229] [Chemistry 64]

[0230]

[0231] [Chemistry 65]

[0232]

[0233] [Chemistry 66]

[0234]

[0235] [Chemistry 67]

[0236]

[0237] [Chemistry 68]

[0238]

[0239] [Chemistry 69]

[0240]

[0241] [Chemistry 70]

[0242]

[0243] [Chemistry 71]

[0244]

[0245] [Chemistry 72]

[0246]

[0247] [Chemistry 73]

[0248]

[0249] [Chemistry 74]

[0250]

[0251] [Chemistry 75]

[0252]

[0253] [Chemistry 76]

[0254]

[0255] [Chemistry 77]

[0256]

[0257] [Chemistry 78]

[0258]

[0259] [Chemistry 79]

[0260]

[0261] [Chemistry 80]

[0262]

[0263] [Chemistry 81]

[0264]

[0265] [Chemistry 82]

[0266]

[0267] [Chemistry 83]

[0268]

[0269] [Chemistry 84]

[0270]

[0271] [Chemistry 85]

[0272]

[0273] [Chemistry 86]

[0274]

[0275] [Chemistry 87]

[0276]

[0277] [Chemistry 88]

[0278]

[0279] [Chemistry 89]

[0280]

[0281] [Chemistry 90]

[0282]

[0283] [Chemistry 91]

[0284]

[0285] [Chemistry 92]

[0286]

[0287] [Chemistry 93]

[0288]

[0289] [Chemistry 94]

[0290]

[0291] [Chemistry 95]

[0292]

[0293] [Chemistry 96]

[0294]

[0295] [Chemistry 97]

[0296]

[0297] [Chemistry 98]

[0298]

[0299] [Chemistry 99]

[0300]

[0301] [Chemistry 100]

[0302]

[0303] [Chemistry 101]

[0304]

[0305] [Chemistry 102]

[0306]

[0307] [Chemistry 103]

[0308]

[0309] [Chemistry 104]

[0310]

[0311] [Chemistry 105]

[0312]

[0313] [Chemistry 106]

[0314]

[0315] [Chemistry 107]

[0316]

[0317] [Chemistry 108]

[0318]

[0319] [Chemistry 109]

[0320]

[0321] [Chemistry 110]

[0322]

[0323] [Chemistry 111]

[0324]

[0325] [Chemistry 112]

[0326]

[0327] [Chemistry 113]

[0328]

[0329] [Chemistry 114]

[0330]

[0331] [Chemistry 115]

[0332]

[0333] [Chemistry 116]

[0334]

[0335] [Chemistry 117]

[0336]

[0337] [Chemistry 118]

[0338]

[0339] [Chemistry 119]

[0340]

[0341] [Chemistry 120]

[0342]

[0343] [Chemistry 121]

[0344]

[0345] [Chemistry 122]

[0346]

[0347] Specific examples of the iodonium cation represented by formula (cation-2) are listed below, but are not limited to these.

[0348] [Chemistry 123]

[0349]

[0350] [Chemistry 124]

[0351]

[0352] Specific examples of the onium salt-type monomer of the present invention include any combination of the above-mentioned anions and cations.

[0353] The onium salt-type monomer of the present invention can be synthesized, for example, by the same method as that for the sulfonium salt having a polymerizable anion described in Japanese Patent No. 5201363, but is not limited thereto.

[0354] [polymer]

[0355] The polymer of the present invention includes a repeating unit derived from an onium salt-type monomer represented by formula (a) (hereinafter also referred to as repeating unit a).

[0356] The polymer of the present invention is a polymer-bonded photoacid generator that functions as a photoacid generator in a chemically amplified resist composition and functions as a base polymer. As structural features of the polymer of the present invention, there can be cited repeating units of sulfonium salts or iodonium salts containing a fluorosulfonic acid anion containing a polymerizable group having a styrene or vinylnaphthalene structure and an aromatic ring substituted by an iodine atom. Since the iodine atom has a great absorption of 13.5nm EUV, secondary electrons are generated during exposure, and the energy of the secondary electrons is transferred to the acid generator, thereby promoting decomposition and thus performing high sensitivity. The polymerizable group composed of styrene and vinylnaphthalene structures has rigidity compared to polymerizable groups such as methacrylate, and the glass transition temperature (Tg) of the polymer is increased. It is believed that the base polymer is regularly arranged by the interaction of aromatic rings within or between base polymers (π-π stacking effect), and also exhibits resistance to pattern collapse in the developer when fine patterns are formed. In addition, in the etching step after fine pattern formation, the aromatic ring directly bonded to the main chain also exhibits excellent etching resistance. In the aromatic ring substituted with iodine atoms, the iodine atom is preferably L in formula (a). B The ortho-bonding of the bonded carbon atoms is expected to inhibit rotation of the bond axis between the aromatic ring to which the polymerizable group is bonded and the aromatic ring to which the iodine atom is bonded. 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.

[0357] 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).

[0358] [Chemistry 125]

[0359]

[0360] In formulas (b1) and (b2), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0361] In formula (b1), X 1 is a single bond, phenylene, naphthylene, *-C(=O)-OX 11 - or *-C(=O)-NH-X 11 -, the phenylene or naphthylene group may be substituted by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group having 1 to 10 carbon atoms which may contain a fluorine atom, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. 11It is a saturated alkylene group, phenylene group, or naphthylene group having 1 to 10 carbon atoms. The saturated alkylene group may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring. * is an atomic bond to a carbon atom in the main chain.

[0362] In formula (b2), X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is an atomic bond to a carbon atom of the main chain. 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 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 from 0 to 4, preferably 0 or 1.

[0363] In formulas (b1) and (b2), AL 1 and AL 2 Each independently represents an acid-labile group. Specific examples of the acid-labile group include, but are not limited to, groups described in JP-A-2013-80033 and JP-A-2013-83821.

[0364] Typically, specific examples of the acid-labile group include those represented by the following formulae (AL-1) to (AL-3).

[0365] [Chemistry 126]

[0366]

[0367] In the formula, * is an atomic bond.

[0368] In formulas (AL-1) and (AL-2), R L1 and R L2 Each is independently a hydrocarbon group having 1 to 40 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. A hydrocarbon group having 1 to 20 carbon atoms is preferred.

[0369] In formula (AL-1), b is an integer of 0-10, preferably an integer of 1-5.

[0370] In formula (AL-2), R L3 and R L4 Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and may also contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, fluorine atoms, and iodine atoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. L2、R L3 and R L4 Any two of them may be bonded to each other and together with the carbon atom or the carbon atom and oxygen 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 preferred, and an alicyclic ring is particularly preferred.

[0371] 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 also contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, fluorine atoms, and iodine atoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. L5 、R L6 and R L7 Any two of them may be bonded to each other and together with the carbon atoms to which they are bonded form a ring having 3 to 20 carbon atoms. The above ring is preferably a ring having 4 to 16 carbon atoms, and is particularly preferably an alicyclic ring.

[0372] Specific examples of the repeating unit b1 include the following repeating units, but are not limited thereto. A and AL 1 Same as above.

[0373] [Chemistry 127]

[0374]

[0375] [Chemistry 128]

[0376]

[0377] [Chemistry 129]

[0378]

[0379] [Chemistry 130]

[0380]

[0381] [Chemistry 131]

[0382]

[0383] [Chemistry 132]

[0384]

[0385] [Chemistry 133]

[0386]

[0387] Specific examples of the repeating unit b2 include the following repeating units, but are not limited thereto. A and AL 2 Same as above.

[0388] [Chemistry 134]

[0389]

[0390] [Chemistry 135]

[0391]

[0392] [Chemistry 136]

[0393]

[0394] The polymer may further include a repeating unit represented by the following formula (b3) (hereinafter also referred to as repeating unit b3).

[0395] [Chemistry 137]

[0396]

[0397] 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. b2 is an integer of 0 to 3 when b1 is 0, and an integer of 0 to 5 when b1 is 1. From the perspective of raw material supply, b2 is preferably 0, 1, 2 or 3, and more preferably 0, 1 or 2.

[0398] In formula (b3), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0399] In formula (b3), X 3 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is an atomic bond to a carbon atom in the main chain. Among these, a single bond and *-C(=O)-O- are preferred, and a single bond is more preferred.

[0400] In formula (b3), R 12 and R 13Each is independently a hydrogen atom or a hydrocarbon group having 1 to 20 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 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, and eicosyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these. In addition, part or all of the hydrogen atoms of the above-mentioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the above-mentioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, the hydrocarbon group may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0401] In addition, R 12 and R 13 They can be bonded to each other to form a ring together with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. In addition, some or all of the hydrogen atoms in the above-mentioned rings may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a portion of the -CH2- in the above-mentioned rings may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, the rings may also contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, and the like.

[0402] 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 hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonthio group having 1 to 20 carbon atoms which may contain a hetero atom, or -N(R 14A )(R 14B ). R 14A and R14B Each independently represents 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 aforementioned hydrocarbon group and the hydrocarbon group portion of the hydrocarbonoxy group, hydrocarbonoxycarbonyl group and hydrocarbonthio group may be saturated or unsaturated, and may be linear, branched or cyclic. As specific examples thereof, there can be mentioned and with respect to R 12 and R 13 The same groups as those exemplified for the hydrocarbon groups represented by . In addition, part or all of the hydrogen atoms of the above hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the -CH2- of the above hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may also be contained. When b2 is 2 or more, each R 14 They can be the same or different from each other.

[0403] In addition, when b2 is 2 or more, multiple R 14 They can be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. In addition, some or all of the hydrogen atoms in the above-mentioned rings may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a portion of the -CH2- in the above-mentioned rings may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, the rings may also contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, and the like.

[0404] In formula (b3), X 4 It is a single bond, an aliphatic alkylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a combination thereof. Among these, a single bond, a carbonyl group, or a sulfonyl group is preferred from the perspective of raw material supply, and a single bond or a carbonyl group is more preferred from the perspective of a polar group generated after the reaction.

[0405] In formula (b3), X 5 and X 6 Each independently represents an oxygen atom or a sulfur atom. 4 and X 6 Bonded to adjacent carbon atoms in an aromatic ring. 5 and X 6 They may be the same or different from each other. From the viewpoint of reactivity, X5 and X 6 Preferably, they are all oxygen atoms.

[0406] Specific examples of the repeating unit b3 include the following repeating units, but are not limited thereto. A As described above, Me is a methyl group. In addition, the bonding positions of the various substituents on the aromatic ring may be interchangeable.

[0407] [Chemistry 138]

[0408]

[0409] [Chemistry 139]

[0410]

[0411] [Chemistry 140]

[0412]

[0413] [Chemistry 141]

[0414]

[0415] [Chemistry 142]

[0416]

[0417] [Chemistry 143]

[0418]

[0419] [Chemistry 144]

[0420]

[0421] [Chemistry 145]

[0422]

[0423] [Chemistry 146]

[0424]

[0425] [Chemistry 147]

[0426]

[0427]

[0428] [Chemistry 149]

[0429]

[0430] [Chemistry 150]

[0431]

[0432] [Chemistry 151]

[0433]

[0434] [Chemistry 152]

[0435]

[0436] [Chemistry 153]

[0437]

[0438] [Chemistry 154]

[0439]

[0440] [Chemistry 155]

[0441]

[0442] [Chemistry 156]

[0443]

[0444] [Chemistry 157]

[0445]

[0446] [Chemistry 158]

[0447]

[0448] [Chemistry 159]

[0449]

[0450] [Chemistry 160]

[0451]

[0452] [Chemistry 161]

[0453]

[0454] [Chemistry 162]

[0455]

[0456] [Chemistry 163]

[0457]

[0458] [Chemistry 164]

[0459]

[0460] [Chemistry 165]

[0461]

[0462] [Chemistry 166]

[0463]

[0464] [Chemistry 167]

[0465]

[0466] [Chemistry 168]

[0467]

[0468] [Chemistry 169]

[0469]

[0470] [Chemistry 170]

[0471]

[0472] [Chemistry 171]

[0473]

[0474] [Chemistry 172]

[0475]

[0476] [Chemistry 173]

[0477]

[0478] [Chemistry 174]

[0479]

[0480] [Chemistry 175]

[0481]

[0482] [Chemistry 176]

[0483]

[0484] [Chemistry 177]

[0485]

[0486] [Chemistry 178]

[0487]

[0488] [Chemistry 179]

[0489]

[0490] [Chemistry 180]

[0491]

[0492] [Chemistry 181]

[0493]

[0494] [Chemistry 182]

[0495]

[0496] [Chemistry 183]

[0497]

[0498] [Chemistry 184]

[0499]

[0500] [Chemistry 185]

[0501]

[0502] [Chemistry 186]

[0503]

[0504] [Chemistry 187]

[0505]

[0506] It is preferred that the polymer further include a repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit c).

[0507] [Chemistry 188]

[0508]

[0509] In formula (c1), R A Y is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is an atomic bond to a carbon atom of the main chain. 21The group is a halogen atom, a nitro group, a cyano 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, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain heteroatoms, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain heteroatoms, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain heteroatoms. c is an integer from 1 to 4. d is an integer from 0 to 3. However, 1 ≤ c + d ≤ 5.

[0510] Specific examples of the repeating unit c include the following repeating units, but are not limited thereto. A Same as above.

[0511] [Chemistry 189]

[0512]

[0513] [Chemistry 190]

[0514]

[0515] [Chemistry 191]

[0516]

[0517] [Chemistry 192]

[0518]

[0519] [Chemistry 193]

[0520]

[0521] It is preferred that the polymer further include a repeating unit represented by the following formula (d1) (hereinafter also referred to as repeating unit d).

[0522] [Chemistry 194]

[0523]

[0524] In formula (d1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 represents a single bond, phenylene, naphthylene, *-C(=O)-OZ 11 - or *-C(=O)-NH-Z 11 -, the phenylene or naphthylene group may be substituted by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group having 1 to 10 carbon atoms which may contain a fluorine atom, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. * is an atomic bond to a carbon atom of the main chain. Z 11R is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group. The saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. 31 A group having 1 to 20 carbon atoms, or a hydrogen atom, or a group containing at least one structure selected from the group consisting of a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-).

[0525] Specific examples of the repeating unit d include the following repeating units, but are not limited thereto. A Same as above.

[0526] [Chemistry 195]

[0527]

[0528] [Chemistry 196]

[0529]

[0530] [Chemistry 197]

[0531]

[0532] [Chemistry 198]

[0533]

[0534] [Chemistry 199]

[0535]

[0536] [Chemistry 200]

[0537]

[0538] [Chemistry 201]

[0539]

[0540] [Chemistry 202]

[0541]

[0542] [Chemistry 203]

[0543]

[0544] [Chemistry 204]

[0545]

[0546] [Chemistry 205]

[0547]

[0548] [Chemistry 206]

[0549]

[0550] [Chemistry 207]

[0551]

[0552] [Chemistry 208]

[0553]

[0554] [Chemistry 209]

[0555]

[0556] [Chemistry 210]

[0557]

[0558] As the repeating unit d, a repeating unit having a lactone ring as a polar group is particularly preferred in ArF lithography, and a repeating unit having a phenol moiety is particularly preferred in KrF lithography, EB lithography, and EUV lithography.

[0559] The polymer may further include 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). The repeating unit e is not particularly limited as long as it has a structure in which one or more hydroxyl groups are protected and the protecting group decomposes upon the action of an acid to generate a hydroxyl group. The repeating unit represented by the following formula (e1) is preferred.

[0560] [Chemistry 211]

[0561]

[0562] In formula (e1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 41 It is a (e+1)-valent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. 42 is an acid-labile group. e is an integer from 1 to 4.

[0563] In formula (e1), R 42 The acid-labile group shown may be any group that generates a hydroxyl group by deprotection by the action of an acid. 42 The structure of is not particularly limited, and an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (e2) and the like are preferred, and an alkoxymethyl group represented by the following formula (e2) is particularly preferred.

[0564] [Chemical formula 212]

[0565]

[0566] In the formula, * represents an atomic bond. R 43 is a hydrocarbon group having 1 to 15 carbon atoms.

[0567] R 42 The acid-labile group represented by and the specific examples of alkoxymethyl and repeating unit e represented by formula (e2) are the same as those exemplified in the description of repeating unit d described in Japanese Patent Application Laid-Open No. 2020-111564.

[0568] 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.

[0569] [Chemical formula 213]

[0570]

[0571] The aforementioned polymer may further contain a repeating unit g derived from styrene, indan, vinylpyridine or vinylcarbazole.

[0572] 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 ≤ 0.4, 0 < b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 ≤ b3 ≤ 0.8, 0 < c ≤ 0.6, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.3, 0 ≤ f ≤ 0.3 and 0 ≤ g ≤ 0.3, more preferably 0 < a ≤ 0.3, 0 < b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 ≤ b3 ≤ 0.7, 0 < c ≤ 0.5, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.2, 0 ≤ f ≤ 0.2 and 0 ≤ g ≤ 0.2. However, a + b1 + b2 + b3 + c + d + e + f + g ≤ 1.0.

[0573] The weight average molecular weight (Mw) of the above polymer is preferably 1000 to 500000, more preferably 3000 to 100000. If Mw is within 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. Moreover, 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.

[0574] Furthermore, the molecular weight distribution (Mw / Mn) of the polymer mentioned above tends to be more affected by the finer pattern pattern. Therefore, in order to obtain a resist composition suitable for use with fine pattern sizes, a narrow Mw / Mn distribution of 1.0 to 2.0 is preferred. Within this range, low-molecular-weight and high-molecular-weight polymers are less abundant, and there is no risk of visible foreign matter on the pattern after exposure or of poor pattern shape.

[0575] Examples of a method for synthesizing the polymer include a method in which a monomer providing the repeating unit is added to an organic solvent with a radical polymerization initiator and then heated to polymerize the monomer.

[0576] 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-mentioned polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylpropionic acid) dimethyl ester, 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, etc. The amount of these initiators added is preferably 0.01 to 25 mol% relative to the total amount of the monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and from the perspective of production efficiency, more preferably 2 to 12 hours.

[0577] The above-mentioned polymerization initiator can be added to the above-mentioned monomer solvent and supplied to the reactor, or the initiator solution can be prepared separately from the above-mentioned monomer solvent and supplied to the reactor respectively and independently. Since it is possible to carry out polymerization reaction and generate ultrahigh molecular weight bodies due to the free radicals generated from the initiator during the standby time, it is better to prepare the monomer solution and the initiator solution separately and add them dropwise from the viewpoint of quality management. The acid-labile group can be directly used as 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, it is also possible to use known chain transfer agents such as dodecanethiol and 2-mercaptoethanol. In this case, the addition amount of these chain transfer agents is preferably 0.01 to 20 mol% relative to the total amount of the monomers to be polymerized.

[0578] In the case of monomers containing hydroxyl groups, the hydroxyl groups can be replaced with acetal groups that are easily deprotected by acid, such as ethoxyethoxy, during polymerization, and deprotected using weak acid and water after polymerization. They can also be replaced with acetyl groups, formyl groups, pivaloyl groups, etc., and alkaline hydrolysis can be performed after polymerization.

[0579] In the case of copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers can be heated and polymerized by adding a free radical polymerization initiator in an organic solvent. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene can be used, and after polymerization, the acetoxy group can be deprotected by alkaline hydrolysis to prepare polyhydroxystyrene or hydroxyvinylnaphthalene.

[0580] Specific examples of the base used in the alkaline hydrolysis include aqueous ammonia, triethylamine, etc. The reaction temperature is preferably -20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0581] The amount of each monomer in the monomer solution may be appropriately set, for example, so as to achieve the desired content ratio of the repeating unit.

[0582] The polymer obtained by the above-mentioned production method can be processed as the final product using the reaction solution obtained by the polymerization reaction, or as the final product using a 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. From the perspective of operating efficiency and quality stabilization, it is preferred to process as the final product a polymer solution obtained by dissolving the powder obtained by the purification step in a solvent.

[0583] Specific examples of the solvent used at this time include ketones such as cyclohexanone and methyl-2-n-pentyl ketone described in paragraphs

[0144] to

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

[0584] In the polymer solution, the concentration of the polymer is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0585] The reaction solution and polymer solution are preferably filtered. Filtering can remove foreign matter and gel that may cause defects, which is effective in stabilizing quality.

[0586] As the material of the filter used in the aforementioned filter filtration, filters made of materials such as fluorocarbon, cellulose, nylon, polyester, and hydrocarbon can be listed. In the filtering step of the chemically amplified resist composition, filters made of fluorocarbon, polyethylene, polypropylene, and other hydrocarbons or nylons called so-called Teflon (registered trademark) are preferred. The pore size of the filter can be appropriately selected according to the target cleanliness, preferably less than 100 nm, and more preferably less than 20 nm. In addition, one of these filters can be used alone, or a combination of multiple filters can be used. The filtration method can allow the solution to pass only once, but it is better to circulate the solution and perform multiple filtrations. The filtration step can be performed in any order and number of times in the manufacturing step of the polymer, and it is better to filter the reaction solution, the polymer solution, or both after the polymerization reaction.

[0587] [Chemically amplified resist composition]

[0588] [(A) Base polymer]

[0589] The chemically amplified resist composition of the present invention contains a base polymer including the above-mentioned polymer as component (A).

[0590] The above-mentioned polymers may be used alone or in combination of two or more polymers having different composition ratios, Mw and / or Mw / Mn. In addition, the base polymer (A) may also include a hydrogenated ring-opening metathesis polymer in addition to the above-mentioned polymers. In this regard, the materials described in Japanese Patent Application Laid-Open No. 2003-66612 may be used.

[0591] [(B) Organic solvent]

[0592] The chemically amplified resist composition of the present invention may contain an organic solvent as component (B). The organic solvent (B) is not particularly limited, as long as it can dissolve the above-mentioned components and the following components. Specific examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ketoalcohols such as 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, t-butyl acetate, t-butyl propionate, and propylene glycol mono-t-butyl ether acetate; lactones such as GBL; and mixed solvents thereof.

[0593] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixed solvents thereof are preferred, as they have particularly excellent solubility in the base polymer of the component (A).

[0594] In the chemically amplified resist composition of the present invention, the content of the organic solvent (B) is preferably 200 to 5000 parts by mass, more preferably 400 to 3500 parts by mass, relative to 80 parts by mass of the base polymer (A). The organic solvent (B) may be used alone or as a mixture of two or more.

[0595] [(C) Quencher]

[0596] The chemically amplified resist composition of the present invention may contain a quencher as component (C). In the present invention, the quencher is a material that traps the acid generated by the photoacid generator in the chemically amplified resist composition, preventing it from diffusing into unexposed areas and forming a desired pattern.

[0597] Specific examples of the (C) quencher include onium salts represented by the following formula (1) or (2).

[0598] [Chemistry 214]

[0599]

[0600] In formula (1), R q1 is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom, except where the hydrogen atom bonded to the carbon atom at the α position of the sulfonic group is substituted by a fluorine atom or a fluoroalkyl group. q2 It is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom.

[0601] R q1 The hydrocarbon group having 1 to 40 carbon atoms represented by the carbon group includes, specifically, alkyl groups having 1 to 40 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 2,6] cyclic saturated hydrocarbon groups having 3 to 40 carbon atoms, such as decyl and adamantyl; aryl groups having 6 to 40 carbon atoms, such as phenyl, naphthyl, and anthracenyl. In addition, some or all of the hydrogen atoms of the above hydrocarbon groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the above hydrocarbon groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, the hydrocarbon groups may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, and the like.

[0602] R q2 The hydrocarbon group represented by R q1 In addition to the substituents exemplified as specific examples of , fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl can be mentioned.

[0603] Specific examples of the anion of the onium salt represented by formula (1) include the following, but are not limited to these.

[0604] [Chemistry 215]

[0605]

[0606] [Chemistry 216]

[0607]

[0608] [Chemistry 217]

[0609]

[0610] [Chemistry 218]

[0611]

[0612] [Chemistry 219]

[0613]

[0614] Specific examples of the anion of the onium salt represented by formula (2) include those shown below, but are not limited to these.

[0615] [Chemistry 220]

[0616]

[0617] [Chemistry 221]

[0618]

[0619] [Chemistry 222]

[0620]

[0621] [Chemistry 223]

[0622]

[0623] [Chemistry 224]

[0624]

[0625] In formulas (1) and (2), Mq + The onium cation is preferably a sulfonium cation represented by the above formula (cation-1), an iodonium cation represented by the above formula (cation-2), or an ammonium cation represented by the following formula (cation-3).

[0626] [Chemistry 225]

[0627]

[0628] In formula (cation-3), R q3 ~R q6 Each independently represents a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. q3 and R q4 They may be bonded to each other and to the nitrogen atom to which they are bonded to form a ring. Specific examples of the aforementioned hydrocarbon groups include, for example, and in the description of formula (cation-1) and (cation-2), R ct1 ~R ct5 The same groups as exemplified for the hydrocarbon groups represented are also included.

[0629] Specific examples of the ammonium cation represented by formula (cation-3) include the following examples, but are not limited to these.

[0630] [Chemistry 226]

[0631]

[0632] Specific examples of the onium salt represented by formula (1) or formula (2) include any combination of the aforementioned anions and cations. Furthermore, these onium salts can be easily prepared by an ion exchange reaction using known organic chemical methods. For ion exchange reactions, reference can be made, for example, to Japanese Patent Application Publication No. 2007-145797.

[0633] 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 onium salt is a conjugate base of a weak acid. The weak acid referred to here refers to a weak acid that exhibits an acidity that is unable to deprotect the acid-labile group of the unit containing the 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 fluorinated at the α-position as a counter anion. That is, when an onium salt that generates a strong acid such as a sulfonic acid fluorinated at the α-position is mixed with an onium salt that generates a weak acid such as a sulfonic acid or carboxylic acid that is not fluorinated, when the strong acid generated by the photoacid generator irradiated with high-energy radiation 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 weaker acid with lower catalytic ability, so that the acid is apparently deactivated and the acid diffusion can be controlled.

[0634] In addition, as the quencher (C), an onium salt having a sulfonium cation and a phenolate anion site in the same molecule as described in Japanese Patent No. 6848776, an onium salt having a sulfonium cation and a carboxylate anion site in the same molecule as described in Japanese Patent No. 6583136 and Japanese Patent Application Laid-Open No. 2020-200311, and an onium salt having an iodonium cation and a carboxylate anion site in the same molecule as described in Japanese Patent No. 6274755 can also be used.

[0635] Here, it is believed that when the photoacid generator that generates a strong acid is an onium salt, the strong acid generated by high-energy ray irradiation can be exchanged for a weak acid as described above. However, on the other hand, the weak acid generated by high-energy ray irradiation is less likely to collide with the unreacted onium salt that generated the strong acid to undergo salt exchange. This is because the onium cation is more likely to form an ion pair with the anion of the strong acid.

[0636] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (1) or (2) as the quencher (C), the content thereof 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 base polymer (A). The onium salt quencher content within the above range is preferred because it provides good resolution and does not significantly reduce sensitivity. The onium salt represented by formula (1) or (2) may be used alone or in combination of two or more.

[0637] The chemically amplified resist composition of the present invention may contain a nitrogen-containing compound as (C) a quencher. Specific examples of such nitrogen-containing compounds include the primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate bond. Furthermore, compounds in which a primary or secondary amine is protected with a carbamate group, such as the compounds described in JP-A-3790649, may also be mentioned.

[0638] Alternatively, sulfonium sulfonates with nitrogen-containing substituents can be used as nitrogen-containing compounds. These compounds function as quenchers in unexposed areas, while neutralizing the exposed areas with the acid they generate, losing their quenching properties and functioning as so-called photodegradable bases. The use of photodegradable bases can further enhance the contrast between exposed and unexposed areas. Examples of photodegradable bases include Japanese Patent Application Publication Nos. 2009-109595 and 2012-46501.

[0639] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as the quencher (C), the content thereof 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 base polymer (A). The nitrogen-containing compound may be used alone or in combination of two or more.

[0640] [(D) Acid generator]

[0641] The chemically amplified resist composition of the present invention may contain an acid generator within a range that does not impair the effects of the present invention. Examples of the acid generator include acid generators that generate acid in response to active light or radiation (photoacid generators). The photoacid generator is not particularly limited as long as it generates acid upon irradiation with high-energy rays, but is preferably an acid generator that generates sulfonic acid, imidic acid, or methide acid. Ideal photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonic acid-type acid generators. Specific examples of the acid generator include the acid generators described in paragraphs

[0122] to

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

[0642] Furthermore, as the photoacid generator, a sulfonium salt represented by the following formula (3-1) or an iodonium salt represented by the following formula (3-2) can also be preferably used.

[0643] [Chemistry 227]

[0644]

[0645] In formulas (3-1) and (3-2), R 101 ~R 105 Each is independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Specific examples of the above halogen atoms and hydrocarbon groups include, for example, and in the description of formulas (cation-1) and (cation-2), R ct1 ~R ct5 The halogen atoms and hydrocarbon groups represented by are the same groups as those exemplified in the hydrocarbon groups. In addition, part or all of the hydrogen atoms of the above hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the -CH2- of the above hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may be contained. In addition, R 101 and R 102 They can be bonded to each other and form a ring together with the sulfur atom to which they are bonded. As a specific example of the ring formed at this time, for example, in the description of formula (cation-1), R ct1 and R ct2 The same rings as those exemplified as the rings that can be formed together with the sulfur atom to which they are bonded are bonded to each other.

[0646] Specific examples of cations of the sulfonium salt represented by formula (3-1) include the same cations as those exemplified as the iodonium cations represented by formula (cation-1). Specific examples of cations of the iodonium salt represented by formula (3-2) include the same cations as those exemplified as the iodonium cations represented by formula (cation-2).

[0647] In formulas (3-1) and (3-2), Xa - is an anion selected from the following formulae (3A) to (3D).

[0648] [Chemistry 228]

[0649]

[0650] In formula (3A), R fa is a hydrocarbon group having 1 to 40 carbon atoms and which may contain a fluorine atom or a heteroatom. The hydrocarbon group may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include R fa1 The same substances as those exemplified in the description of .

[0651] As the anion represented by formula (3A), a group represented by the following formula (3A') is preferred.

[0652] [Chemistry 229]

[0653]

[0654] In formula (3A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0655] In formula (3A'), R fa1 The hydrocarbon group may contain a heteroatom having 1 to 38 carbon atoms. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, or a halogen atom, and more preferably an oxygen atom. The hydrocarbon group is preferably a hydrocarbon group having 6 to 30 carbon atoms from the viewpoint of achieving high resolution in fine pattern formation.

[0656] R fa1 The hydrocarbon group having 1 to 38 carbon atoms 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, and eicosyl; cyclic saturated hydrocarbon groups having 3 to 38 carbon atoms, such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated aliphatic hydrocarbon groups having 2 to 38 carbon atoms, such as allyl and 3-cyclohexenyl; aryl groups having 6 to 38 carbon atoms, such as phenyl, 1-naphthyl, and 2-naphthyl; aralkyl groups having 7 to 38 carbon atoms, such as benzyl and diphenylmethyl; and groups obtained by combining these.

[0657] Furthermore, some or all of the hydrogen atoms of the above-mentioned hydrocarbon groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms. A portion of the -CH2- group of the above-mentioned hydrocarbon groups may also be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms. Consequently, the hydrocarbon groups may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, and the like. Furthermore, the above-mentioned heteroatoms are preferably oxygen atoms. Specific examples of hydrocarbon groups containing heteroatoms include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, and 3-oxocyclohexyl.

[0658] The synthesis of sulfonium salts containing anions represented by formula (3A′) is described in detail in Japanese Patent Application Laid-Open Nos. 2007-145797, 2008-106045, 2009-7327, and 2009-258695. Furthermore, it is also desirable to use sulfonium salts described in Japanese Patent Application Laid-Open Nos. 2010-215608, 2012-41320, 2012-106986, and 2012-153644.

[0659] 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.

[0660] [Chemistry 230]

[0661]

[0662] [Chemistry 231]

[0663]

[0664] [Chemistry 232]

[0665]

[0666] [Chemistry 233]

[0667]

[0668] In formula (3B), R fb1 and R fb2 Each independently represents 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: 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.

[0669] In formula (3C), R fc1 、R fc2 and Rfc3 Each independently represents 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: fa1 The same groups as those exemplified for the hydrocarbon groups represented by R fc1 、R fc2 and R fc3 It is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 Can bond to each other and to the groups to which they are bonded (-CF2-SO2-C - -SO2-CF2-) together to form a ring, at this time, R fc1 and R fc2 The group obtained by bonding to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0670] In formula (3D), R fd is a hydrocarbon group having 1 to 40 carbon atoms which may contain heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated and may be linear, branched or cyclic. As specific examples thereof, the following are mentioned: fa1 The same groups as those exemplified for the hydrocarbon groups represented by

[0671] For details on the synthesis of the sulfonium salt containing the anion represented by formula (3D), see JP-A-2010-215608 and JP-A-2014-133723.

[0672] Specific examples of the anion represented by formula (3D) include those shown below, but are not limited to these.

[0673] [Chemistry 234]

[0674]

[0675] [Chemistry 235]

[0676]

[0677] Furthermore, the photoacid generator containing the anion represented by formula (3D) does not have a fluorine atom at the α-position of the sulfonic group, but has two trifluoromethyl groups at the β-position. Therefore, it has sufficient acidity to cleave the acid-labile groups in the base polymer. Therefore, it can be used as a photoacid generator.

[0678] As the photoacid generator, a substance represented by the following formula (4) can also be preferably used.

[0679] [Chemistry 236]

[0680]

[0681] In formula (4), R 201 and R 202 Each independently represents a hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. 203 is a C1-30 alkylene group which may contain a heteroatom. 201 、R 202 and R 203 Any two of them may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, as a specific example of the above ring, the same as those used as R in the description of formula (cation-1) can be cited. ct1 and R ct2 The rings that can be bonded to each other and to form a ring together with the sulfur atom to which they are bonded are the same as the rings exemplified.

[0682] R 201 and R 202 The hydrocarbon group having 1 to 30 carbon atoms represented by may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 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, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6 ] Cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, such as decyl and adamantyl; aromatic groups having 6 to 30 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl and anthracenyl; groups obtained by combining these groups, etc. In addition, part or all of the hydrogen atoms of the above-mentioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the above-mentioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, the hydrocarbon group may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0683] R 203The alkylene group having 1 to 30 carbon atoms may be saturated or unsaturated and may 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-114-diyl, pentadecane-115-diyl, hexadecane-116-diyl, heptane-1,17-diyl and the like. -alkanediyl having 1 to 30 carbon atoms, such as cyclopentanediyl, cyclohexanediyl, norbornanediyl, and adamantanediyl; cyclic saturated alkylene groups having 3 to 30 carbon atoms, such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, and tert-butylnaphthylene; and groups obtained by combining these groups. Furthermore, some or all of the hydrogen atoms of the above-mentioned alkylene group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms, and some or all of the -CH2- of the above-mentioned alkylene group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms. As a result, the group may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, and the like. As the above-mentioned heteroatoms, oxygen atoms are preferred.

[0684] In formula (4), L 1 is a single bond, an ether bond or an alkylene group having 1 to 20 carbon atoms which may contain heteroatoms. The alkylene group may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include: 203 The groups are the same as those exemplified for the hydrocarbylene group represented by .

[0685] In formula (4), X a 、X b 、X c and X d Each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group. a 、X b 、X c and X d At least one of them is a fluorine atom or a trifluoromethyl group.

[0686] In formula (4), k is an integer from 0 to 3.

[0687] As the photoacid generator represented by formula (4), a group represented by the following formula (4') is preferred.

[0688] [Chemistry 237]

[0689]

[0690] In formula (4'), L 1 Same as above. X e is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 、R 302 and R 303 Each is independently a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms. The hydrocarbon group may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include: fa1 The same groups as those exemplified for the hydrocarbon group represented by .x and y are each independently an integer of 0 to 5.z is an integer of 0 to 4.

[0691] Specific examples of the photo-acid generator represented by formula (4) include the same photo-acid generators as those exemplified as the photo-acid generator represented by formula (2) in JP-A-2017-26980.

[0692] Among the aforementioned photoacid generators, compounds containing anions represented by formula (3A') or (3D) are particularly preferred due to their low acid diffusion and excellent solubility in solvents. Compounds represented by formula (4') are particularly preferred due to their extremely low acid diffusion.

[0693] Furthermore, 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.

[0694] [Chemistry 238]

[0695]

[0696] 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.

[0697] In formulas (5-1) and (5-2), L 11 It is a single bond, an ether bond, an ester bond, or a saturated alkylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated alkylene group may be linear, branched, or cyclic.

[0698] In formulas (5-1) and (5-2), L 12 When p is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms. When p is 2 or 3, it is a (p+1)-valent linking group having 1 to 20 carbon atoms. The linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0699] 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 hydrocarbonoxy group having 1 to 20 carbon atoms, a hydrocarboncarbonyl group having 2 to 20 carbon atoms, a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms, or a hydrocarbonsulfonyloxy group having 1 to 20 carbon atoms, which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group, or an ether bond, or -N(R 401A )(R 401B )、-N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-O-. R 401D 、R 401A and R 401B Each independently represents a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. 401C R is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbonoxy group having 1 to 6 carbon atoms, a saturated hydrocarboncarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarboncarbonyloxy group having 2 to 6 carbon atoms. 401D It 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 also 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 aliphatic hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 They can be the same or different from each other.

[0700] Among them, as R 401 , hydroxyl, -N(R 401C )-C(=O)-R 401D 、-N(R 401C )-C(=O)-OR 401D , fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group and the like are preferred.

[0701] In formulas (5-1) and (5-2), Rf 1 ~Rf 4Each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 can combine to form a carbonyl group. In particular, Rf 3 and Rf 4 Preferably, they are all fluorine atoms.

[0702] In formulas (5-1) and (5-2), R 402 ~R 406 Each independently represents a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated and may be linear, branched or cyclic. As a specific example, for example, in the description of formula (cation-1) and (cation-2), R ct1 ~R ct5 The same groups as those exemplified for the hydrocarbon groups represented by . In addition, part or all of the hydrogen atoms of the above hydrocarbon groups may be substituted with hydroxyl groups, carboxyl groups, halogen atoms, cyano groups, nitro groups, mercapto groups, sultone rings, sulfo groups or groups containing sulfonium salts, and part of the -CH2- of the above hydrocarbon groups may be substituted with ether bonds, ester bonds, carbonyl groups, amide bonds, carbonate bonds or sulfonate bonds. In addition, R 402 and R 403 They may be bonded to each other and to the sulfur atom to which they are bonded to form a ring. In this case, as a specific example of the above ring, for example, and as R in the description of formula (cation-1) ct1 and R ct2 The rings that can be bonded to each other and to form a ring together with the sulfur atom to which they are bonded are the same as the rings exemplified.

[0703] Specific examples of the cation of the sulfonium salt represented by formula (5-1) include the same cations as those exemplified as the sulfonium cation represented by formula (cation-1). Specific examples of the cation of the iodonium salt represented by formula (5-2) include the same cations as those exemplified as the iodonium cation represented by formula (cation-2).

[0704] Specific examples of the anion of the onium salt represented by formula (5-1) or (5-2) include those shown below, but are not limited to these.

[0705] [Chemistry 239]

[0706]

[0707] [Chemistry 240]

[0708]

[0709] [Chemistry 241]

[0710]

[0711] [Chemistry 242]

[0712]

[0713] [Chemistry 243]

[0714]

[0715] [Chemistry 244]

[0716]

[0717] [Chemistry 245]

[0718]

[0719] [Chemistry 246]

[0720]

[0721] [Chemistry 247]

[0722]

[0723] [Chemistry 248]

[0724]

[0725] [Chemistry 249]

[0726]

[0727] [Chemistry 250]

[0728]

[0729] [Chemistry 251]

[0730]

[0731] [Chemistry 252]

[0732]

[0733] [Chemistry 253]

[0734]

[0735] [Chemistry 254]

[0736]

[0737] [Chemistry 255]

[0738]

[0739] [Chemistry 256]

[0740]

[0741] [Chemistry 257]

[0742]

[0743] [Chemistry 258]

[0744]

[0745] [Chemistry 259]

[0746]

[0747] [Chemistry 260]

[0748]

[0749] When the chemically amplified resist composition of the present invention contains an acid generator (D), its content is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass, relative to 80 parts by mass of the base polymer (A). An amount of the acid generator (D) within the aforementioned range is preferred because it provides excellent resolution and eliminates the risk of foreign matter appearing after development or during stripping of the resist film. The acid generator (D) may be used alone or in combination of two or more.

[0750] [(E) Surfactant]

[0751] The chemically amplified resist composition of the present invention may further contain a surfactant as component (E). The surfactant (E) is preferably a surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer, or a surfactant that is insoluble or poorly soluble in both water and an alkaline developer. Such surfactants can be found in Japanese Patent Application Publication Nos. 2010-215608 and 2011-16746.

[0752] Among the surfactants described in the aforementioned publication, preferred surfactants are those that are insoluble or poorly soluble in water and alkaline developer, such as FC-4430 (manufactured by 3M Co.), Surflon (registered trademark) S-381 (manufactured by AGC Seimichemical Co., Ltd.), Olfine (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20 and KH-30 (manufactured by AGC Seimichemical Co., Ltd.), and an oxetane ring-opening polymer represented by the following formula (surf-1).

[0753] [Chemistry 261]

[0754]

[0755] Here, R, Rf, A, B, C, m, and n are independent of the above descriptions and apply only to formula (surf-1). R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. Examples of the aforementioned aliphatic group include ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, and 1,5-pentylene as divalent groups, and the following as trivalent or tetravalent groups.

[0756] [Chemistry 262]

[0757]

[0758] In the formula, the dotted lines are atomic bonds, which are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.

[0759] Among them, 1,4-butylene and 2,2-dimethyl-1,3-propylene are preferred.

[0760] Rf is a trifluoromethyl group or a pentafluoroethyl group, preferably a trifluoromethyl group. m is an integer from 0 to 3, n is an integer from 1 to 4, the sum of n and m is the valence of R, and 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 the structural units in formula (surf-1) is not specified, and they can be bonded in blocks or randomly. The production of surfactants based on partially fluorinated oxetane ring-opening polymers is described in detail in the specification of U.S. Patent No. 5,650,483.

[0761] In ArF immersion lithography, where a resist overcoat is not used, surfactants that are insoluble or poorly soluble in water but soluble in alkaline developer solutions have the function of reducing water infiltration and outflow by aligning the resist film surface. Therefore, they can be used to reduce damage to exposure equipment by inhibiting the elution of water-soluble components from the resist film. Furthermore, they dissolve during alkaline aqueous solution development after exposure or after a post-exposure bake (PEB) and are less likely to become foreign matter that causes defects. Such surfactants are insoluble or poorly soluble in water but soluble in alkaline developer solutions. They are polymeric surfactants, also known as hydrophobic resins. Surfactants with high water repellency and improved water slip properties are particularly preferred.

[0762] Specific examples of such polymeric surfactants include polymeric surfactants containing at least one type of repeating unit selected from the group consisting of repeating units represented by the following formulae (6A) to (6E).

[0763] [Chemistry 263]

[0764]

[0765] In formulas (6A) to (6E), R B W is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 R is -CH2-, -CH2CH2-, -O- or two -H separated from each other. s1 Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. s2 R is a single bond or a straight-chain or branched alkylene group having 1 to 5 carbon atoms. s3 Each R is independently a hydrogen atom, a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group. s3 In the case of a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between carbon-carbon bonds. s4 is a (u+1)-valent hydrocarbon group or a fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer of 1 to 3. s5 Each independently represents a hydrogen atom, or -C(=O)-OR sa The group represented by R sa is a fluorinated hydrocarbon group having 1 to 20 carbon atoms. s6 It is a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, and an ether bond or a carbonyl group may be inserted between carbon-carbon bonds.

[0766] R s1 The hydrocarbon group having 1 to 10 carbon atoms represented by is preferably a saturated hydrocarbon group and may be linear, branched, or cyclic. Specific examples 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, and n-decyl; and cyclic saturated hydrocarbon groups having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl. Among these, alkyl groups having 1 to 6 carbon atoms are preferred.

[0767] R s2 The hydrocarbylene group represented by is preferably a saturated hydrocarbylene group and may be linear, branched or cyclic. Specific examples thereof include methylene, ethylene, propylene, butylene and pentylene.

[0768] R s3 or R s6 The hydrocarbon group represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include aliphatic unsaturated hydrocarbon groups such as saturated hydrocarbon groups, alkenyl groups, and alkynyl groups, with saturated hydrocarbon groups being preferred. Specific examples of the above-mentioned saturated hydrocarbon groups include R s1 Examples of the hydrocarbon group represented by include undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and the like. s3or R s6 Specific examples of the fluorinated hydrocarbon groups represented by include groups in which some or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon groups are substituted with fluorine atoms. As described above, an ether bond or a carbonyl group may be inserted between these carbon-carbon bonds.

[0769] R s3 Specific examples of the acid-labile group include the groups represented by the aforementioned formulae (AL-3) to (AL-5), trialkylsilyl groups wherein each alkyl group is an alkyl group having 1 to 6 carbon atoms, and alkyl groups having 4 to 20 carbon atoms and containing an oxo group.

[0770] R s4 The (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group represented by may be linear, branched, or cyclic. Specific examples thereof include groups obtained by removing u hydrogen atoms from the above-mentioned hydrocarbon group or fluorinated hydrocarbon group.

[0771] R sa The fluorinated hydrocarbon group represented by is preferably saturated and may be linear, branched or cyclic. Specific examples thereof include groups in which some or all of the hydrogen atoms of the above hydrocarbon groups are substituted with fluorine atoms, and specific examples thereof include 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, and 2-(perfluorodecyl)ethyl.

[0772] Specific examples of the repeating unit represented by any one of formulae (6A) to (6E) include the following, but are not limited thereto. B Same as above.

[0773] [Chemistry 264]

[0774]

[0775] [Chemistry 265]

[0776]

[0777] [Chemistry 266]

[0778]

[0779] [Chemistry 267]

[0780]

[0781] [Chemistry 268]

[0782]

[0783] 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 other repeating units include repeating units obtained from methacrylic acid, α-trifluoromethylacrylic 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 further preferably 100 mol% in all the repeating units.

[0784] The Mw of the polymeric surfactant is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. The Mw / Mn ratio is preferably 1.0 to 2.0, more preferably 1.0 to 1.6.

[0785] As a method for synthesizing the aforementioned polymeric surfactant, the following method can be cited: a monomer containing an unsaturated group that provides repeating units represented by formula (6A) to formula (6E) and other repeating units as needed is added with a free radical initiator in an organic solvent and heated to polymerize. Specific examples of the organic solvent used in the polymerization include: toluene, benzene, THF, diethyl ether, dioxane, etc. Specific examples of the polymerization initiator include: AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylpropionic acid) dimethyl ester, benzoyl peroxide, lauroyl peroxide, etc. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. The acid-labile group can be used directly as the acid-labile group introduced into the monomer, or it can be protected or partially protected after polymerization.

[0786] When synthesizing the aforementioned polymeric surfactant, a known chain transfer agent such as dodecanethiol or 2-mercaptoethanol may be used to adjust the molecular weight. In this case, the amount of such chain transfer agent added is preferably 0.01 to 10 mol % relative to the total molar amount of the monomers to be polymerized.

[0787] When the chemically amplified resist composition of the present invention includes a surfactant (E), 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 the base polymer (A). When the content of the surfactant (E) is 0.1 parts by mass or greater, the receding contact angle of the resist film surface with water is sufficiently increased. When the content is 50 parts by mass or less, the dissolution rate of the resist film surface in the developer is slow, allowing the height of the formed fine pattern to be sufficiently maintained. The surfactant (E) may be used alone or in combination of two or more.

[0788] [(F) Dissolution inhibitor]

[0789] 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 a positive-type resist, the addition of the dissolution inhibitor can further increase the difference in dissolution rate between the exposed and unexposed areas, thereby further improving resolution.

[0790] Specific examples of the dissolution inhibitor include compounds having a molecular weight of preferably 100 to 1000, more preferably 150 to 800, wherein the hydrogen atoms of the phenolic hydroxyl groups are substituted with acid-labile groups at a ratio of 0 to 100 mol % or more, or compounds containing a carboxylic acid in the molecule wherein the hydrogen atoms of the carboxylic acid are substituted with acid-labile groups at an average ratio of 50 to 100 mol %. Specifically, examples include compounds wherein the hydrogen atoms of the hydroxyl and carboxyl groups of bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalenecarboxylic acid, adamantanecarboxylic acid, and cholic acid are substituted with acid-labile groups. For example, the compounds described in paragraphs

[0155] to

[0178] of Japanese Patent Application Laid-Open No. 2008-122932 may be cited.

[0791] 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 the base polymer (A). The dissolution inhibitor (F) may be used alone or in combination of two or more.

[0792] [(G) Other ingredients]

[0793] In the chemically amplified resist composition of the present invention, as for (G) other components, compounds that decompose and generate acid due to acid (acid proliferation compounds), organic acid derivatives, fluorinated alcohols, water repellency enhancers, etc. may be contained. As the above-mentioned acid proliferation compounds, reference may be made to the compounds described in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608. When the above-mentioned acid proliferation compound is contained, 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 base polymer (A). If the content is too much, it is difficult to control the diffusion of acid, which sometimes causes degradation of resolution and degradation of pattern shape. As the above-mentioned organic acid derivatives and fluorinated alcohols, reference may be made to the compounds described in Japanese Patent Application Publication No. 2009-269953 or Japanese Patent Application Publication No. 2010-215608.

[0794] The aforementioned water repellency improver can be used for immersion lithography without using a top coat. As the aforementioned water repellency improver, it is preferable to enumerate: a polymer comprising a fluorinated alkyl group, a polymer comprising 1,1,1,3,3,3-hexafluoro-2-propanol residues of a specific structure, and more preferably a polymer exemplified in Japanese Patent Application Publication No. 2007-297590 and Japanese Patent Application Publication No. 2008-111103. The aforementioned water repellency improver needs to be dissolved in an alkaline developer or an organic solvent developer. The above-mentioned specific water repellency improver with 1,1,1,3,3,3-hexafluoro-2-propanol residues has good solubility in a developer. As a water repellency improver, a polymer comprising a repeating unit containing an amino group or an amine salt prevents the evaporation of the acid in the PEB and prevents the poor opening of the hole pattern after development. When the chemically amplified resist composition of the present invention contains the water repellency enhancer, the content thereof 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 base polymer (A).

[0795] [Pattern Formation Method]

[0796] When the chemically amplified resist composition of the present invention is used to manufacture various integrated circuits, known photolithography methods can be applied. For example, a patterning method includes the following steps: forming a resist film on a substrate using the chemically amplified resist composition; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

[0797] First, the chemically amplified resist composition of the present invention is applied to a substrate (e.g., Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective film) used in integrated circuit manufacturing or a substrate (e.g., Cr, CrO, CrON, MoSi2, SiO2) used in mask circuit manufacturing by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor blade coating to a coating thickness of 0.01 to 2.0 μm. The resist composition is then prebaked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0798] Next, the resist film is exposed using high-energy rays. Examples of the high-energy rays include ultraviolet rays, far ultraviolet rays, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer lasers, gamma rays, and synchrotron radiation. Examples of the high-energy rays include ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, gamma rays, and synchrotron radiation. When ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, gamma rays, and synchrotron radiation are used as the high-energy rays, the exposure is preferably 1 to 200 mJ / cm2 directly or using a mask for forming a target pattern. 2 About 10-100 mJ / cm 2 When EB is used as the high energy ray, the exposure dose is preferably 0.1 to 100 μC / cm 2 About 0.5 to 50 μC / cm 2 The chemically amplified resist composition of the present invention is particularly suitable for fine patterning using high-energy radiation, such as ArF excimer lasers with a wavelength of 193 nm, KrF excimer lasers with a wavelength of 248 nm, EB, EUV radiation with a wavelength of 3 to 15 nm, X-rays, soft X-rays, gamma rays, or synchrotron radiation.

[0799] After the exposure, PEB may be performed on a hot plate at preferably 60-150° C. for 10 seconds to 30 minutes, more preferably 80-120° C. for 30 seconds to 20 minutes.

[0800] After exposure or PEB, a developer containing 0.1 to 10% by mass, preferably 2 to 5% by mass, of an alkaline aqueous solution of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or the like is used, and development is performed for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by conventional methods such as dipping, puddle, or spraying. This allows the irradiated portion to dissolve in the developer, while the unexposed portion remains in the developer, thereby forming a target positive pattern on the substrate.

[0801] Alternatively, an organic solvent developer may be used instead of the alkaline aqueous solution to obtain a negative pattern. Specific examples of the developer used in this case include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, methyl crotonate, methyl crotonate, methyl pentanoate, methyl croton ... Ethyl beanate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0802] After development is complete, rinsing may be performed. A rinsing solution is preferably a solvent that is miscible with the developer and does not dissolve the resist film. Preferred solvents include alcohols with 3 to 10 carbon atoms, ether compounds with 8 to 12 carbon atoms, and alkanes, alkenes, and alkynes with 6 to 12 carbon atoms, as well as aromatic solvents.

[0803] 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, neopentyl alcohol, 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.

[0804] Specific examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-amyl ether, diisoamyl ether, di-sec-amyl ether, di-tert-amyl ether, and di-n-hexyl ether.

[0805] Specific examples of the alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Specific examples of the alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Specific examples of the alkynes having 6 to 12 carbon atoms include hexyne, heptyne, and octyne.

[0806] Specific examples of the aromatic solvent include toluene, xylene, ethylbenzene, cumene, tert-butylbenzene, and mesitylene.

[0807] By performing rinsing, the collapse of the resist pattern and the generation of defects can be reduced. In addition, rinsing is not essential, and by not performing rinsing, the amount of solvent used can be reduced.

[0808] The developed hole or groove pattern can also be shrunk using heat flow, RELACS, or DSA. A shrinking agent is applied to the hole pattern. During baking, the acidic catalyst from the resist film diffuses, causing crosslinking of the shrinking agent on the surface of the resist film and adhering to the sidewalls of the hole pattern. The baking temperature is preferably 70-180°C, more preferably 80-170°C, and the baking time is preferably 10-300 seconds to remove excess shrinking agent and shrink the hole pattern.

[0809] Example

[0810] Hereinafter, the present invention will be described in detail with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples.

[0811] MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0812] [1] Synthesis of onium salt monomers

[0813] [Example 1-1] Synthesis of Onium Salt Monomer a-1

[0814] [Chemistry 269]

[0815]

[0816] (1) Synthesis of intermediate In-1

[0817] Under a nitrogen atmosphere, the raw materials SM-1 (37.2 g), triethylamine (18.0 g) and 4-dimethylaminopyridine (1.5 g) were dissolved or suspended in THF (200 g) in a reaction vessel and cooled in an ice bath. Then, THF (30 g) in which p-styrenesulfonyl chloride (16.4 g) was dissolved was added dropwise. After the addition, the temperature in the reaction vessel was raised to 50°C and matured for 6 hours. Then, the reaction solution was cooled and a 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 general aqueous work-up, and after distilling the solvent, purified by silica gel chromatography to obtain 45.8 g of intermediate In-1 (yield 97%) as an oil.

[0818] (2) Synthesis of intermediate In-2

[0819] Under a nitrogen environment, the intermediate In-1 (45.8 g) was dissolved in THF (200 g). While cooling in an ice bath, a 25% by mass aqueous solution of sodium hydroxide (15.5 g) was added dropwise. After the addition, the temperature in the reaction vessel was raised to 30°C and matured for 12 hours. After maturation, the reaction solution was cooled and 20% by mass hydrochloric acid (18.2 g) was added dropwise to stop the reaction. The target product was extracted twice with ethyl acetate (200 g), and a general aqueous work-up was performed. After the solvent was distilled off, it was recrystallized with hexane to obtain 37.5 g of intermediate In-2 (yield 90%) as white crystals.

[0820] (3) Synthesis of intermediate In-3

[0821] Under a nitrogen environment, the intermediate In-2 (37.5g), the raw material SM-2 (28.0g), 4-dimethylaminopyridine (1.1g) and dichloromethane (150g) were added to the reaction vessel and cooled in an ice bath. While maintaining the temperature in the reaction vessel below 20°C, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (20.1g) was directly added in the form of a powder. After addition, the temperature was raised to room temperature and matured for 12 hours. After maturation, water (100g) was added to stop the reaction, and a general aqueous work-up was performed. After distilling off the solvent, diisopropyl ether was added for recrystallization, thereby obtaining 55.7g of the intermediate In-3 (yield 89%) in the form of an oil.

[0822] (4) Synthesis of onium salt monomer a-1

[0823] Under a nitrogen atmosphere, intermediate In-3 (55.7 g), raw material SM-3 (31.8 g), chloromethane (200 g), and water (150 g) were added to a reaction vessel and stirred for 30 minutes. The organic layer was separated, washed with water, and then concentrated under reduced pressure. The concentrate was purified by silica gel chromatography to obtain 64.2 g of the target monomer a-1 as an oil (yield 86%).

[0824] MALDI TOF-MS:POSITIVE M + 261 (equivalent to C 18 H 13 S + )

[0825] NEGATIVE M - 783 (equivalent to C 21 H9F4I2O8S2 - )

[0826] [Examples 1-2 to 1-7] Synthesis of Onium Salt-Type Monomers a-2 to a-7

[0827] Onium salt-type monomers a-2 to a-7 represented by the following formulae were synthesized using corresponding raw materials and known organic synthesis reactions.

[0828] [Chemistry 270]

[0829]

[0830] [Comparative Examples 1-1 to 1-4] Comparative Synthesis of Onium Salt Monomers ca-1 to ca-4

[0831] Comparative onium salt-type monomers ca-1 to ca-4 represented by the following formulae were synthesized using corresponding raw materials and known organic synthesis reactions.

[0832] [Chemistry 271]

[0833]

[0834] [2] Synthesis of base polymer

[0835] Among the monomers used for synthesis of the base polymer, monomers other than monomer a-1 to monomer a-7 and comparative monomer ca-1 to comparative monomer ca-4 are as follows.

[0836] [Chemistry 272]

[0837]

[0838] [Chemistry 273]

[0839]

[0840] [Chemistry 274]

[0841]

[0842] [Example 2-1] Synthesis of polymer P-1

[0843] Under a nitrogen atmosphere, monomer a-1 (54.1 g), monomer b1-1 (35.6 g), monomer c-1 (10.4 g), 3.34 g of V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, 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 added and heated to 80°C while stirring. The monomer-polymerization initiator solution was then added dropwise over 4 hours. After the addition was complete, stirring was continued for 2 hours while maintaining the polymerization solution at 80°C, followed by cooling to room temperature. The resulting polymerization solution was added dropwise to 3000 g of vigorously stirred hexane, and the precipitated polymer was separated by filtration. The resulting polymer was washed twice with 600 g of hexane and then vacuum-dried at 50°C for 20 hours to obtain polymer P-1 as a white powder (yield 95.1 g, yield 95%). The Mw of polymer P-1 was 9200, and Mw / Mn was 1.73. Mw is a polystyrene-equivalent measurement value obtained by GPC using DMF as a solvent.

[0844] [Chemistry 275]

[0845]

[0846] [Examples 2-2 to 2-20, Comparative Examples 2-1 to 2-10] Synthesis of Polymers P-2 to P-20 and Comparative Polymers CP-1 to CP-10

[0847] The polymers shown in Tables 1 and 2 were produced by the same method as in Example 2-1 except that the types and blending ratios of the monomers were changed.

[0848] [Table 1]

[0849]

[0850] [Table 2]

[0851]

[0852] [3] Preparation of chemically amplified resist compositions

[0853] [Examples 3-1 to 3-20, Comparative Examples 3-1 to 3-10]

[0854] Specified components selected from the base polymers of the present invention (P-1 to P-20), comparative base polymers (CP-1 to CP-10), acid generators (PAG-1 and PAG-2), and quenchers (SQ-1 to SQ-3AQ-1) were dissolved in a solvent containing 0.01% by mass of FC-4430 manufactured by 3M Company as a surfactant at the compositions shown in Tables 3 and 4 below to prepare solutions. The solutions were then filtered through a 0.2 μm Teflon (registered trademark) filter to prepare chemically amplified resist compositions (R-1 to R-20, CR-1 to CR-10).

[0855] [Table 3]

[0856]

[0857] [Table 4]

[0858]

[0859]

[0860] In Tables 3 and 4, the solvents, quenchers (SQ-1 to SQ-3, AQ-1), and acid generators (PAG-1, PAG-2) are as follows.

[0861] Solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0862] DAA (Diacetone Alcohol)

[0863] Quencher: SQ-1~SQ-3, AQ-1

[0864] [Chemistry 276]

[0865]

[0866] Acid generator: PAG-1, PAG-2

[0867] [Chemistry 277]

[0868]

[0869] [4]EUV lithography evaluation (1)

[0870] [Examples 4-1 to 4-20, Comparative Examples 4-1 to 4-10]

[0871] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-10) shown in Tables 3 and 4 was spin-coated onto a Si substrate on which a 20 nm thick silicon-containing spin-on hard mask SHB-A940 (silicon content: 43 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. was formed. The film was pre-baked at 100°C for 60 seconds using a hot plate to form a 50 nm thick resist film. The resist film was exposed to an LS pattern with a size of 18 nm and a pitch of 36 nm on the wafer using an EUV scanner NXE 3300 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, dipole illumination). The exposure dose and focus (exposure dose pitch: 1 mJ / cm) were varied. 2 After exposure, PEB was performed for 60 seconds at the temperatures shown in Tables 5 and 6. The pattern was then developed by immersion in a 2.38% by mass TMAH aqueous solution for 30 seconds, rinsed with a rinse material containing a surfactant, and spin-dried to obtain a positive pattern.

[0872] The obtained LS pattern was observed using a Hitachi Advanced Technologies Co., Ltd. long-range SEM (CG6300), 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.

[0873] [Sensitivity evaluation]

[0874] Find the optimal exposure dose Eop (mJ / cm2) to obtain an LS pattern with a line width of 18 nm and a pitch of 36 nm. 2 ) as the sensitivity. The smaller the value, the higher the sensitivity.

[0875] [EL evaluation]

[0876] The EL (unit: %) was calculated from the following formula based on the exposure amount formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm space width in the LS pattern. The larger the value, the better the performance.

[0877] EL (%) = (E1-E2 / Eop) × 100

[0878] E1: Provides the optimal exposure for LS patterns with a line width of 16.2nm and a pitch of 36nm

[0879] E2: Provides the optimal exposure for LS patterns with a line width of 19.8nm and a pitch of 36nm

[0880] Eop: Provides the optimal exposure for LS patterns with a line width of 18nm and a pitch of 36nm

[0881] [LWR evaluation]

[0882] For the LS pattern obtained by irradiation with Eop, the dimensions of the line were measured at 10 locations along the length of the line. From these measurements, the value (3σ) tripled from the standard deviation (σ) was calculated as the LWR. The smaller this value, the less roughness and more uniform the line width of the pattern.

[0883] [DOF evaluation]

[0884] As a depth of focus evaluation, the focus range formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm size in the LS pattern was determined. The larger the value, the wider the depth of focus.

[0885] [Evaluation of Collapse Limit of Line Pattern]

[0886] Measure the line size at each exposure dose at the optimal focus of the LS pattern at 10 locations along the length direction. The thinnest line size obtained without collapse is defined as the collapse limit size. The smaller this value, the better the collapse limit.

[0887] [Table 5]

[0888]

[0889]

[0890] [Table 6]

[0891]

[0892] The results shown in Tables 5 and 6 demonstrate that chemically amplified resist compositions using a base polymer containing repeating units derived from the onium salt-type monomer of the present invention exhibit good sensitivity and excellent EL, LWR, and DOF. Furthermore, they exhibited a low collapse threshold, demonstrating resistance to pattern collapse even during fine pattern formation. Therefore, the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[0893] [5]EUV lithography evaluation (2)

[0894] [Examples 5-1 to 5-20, Comparative Examples 5-1 to 5-10]

[0895] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-10) shown in Tables 3 and 4 was spin-coated onto a 20 nm thick Si substrate with a Shin-Etsu Chemical Co., Ltd. silicon-containing spin-on hard mask SHB-A940 (silicon content: 43 mass%). The resulting film was pre-baked for 60 seconds at 105°C using a hot plate to form a 50 nm thick resist film. This resist film was then exposed using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask with a hole pattern of 46 nm pitch on the wafer, +20% bias). PEB was then performed for 60 seconds using a hot plate at the temperatures listed in Tables 7 and 8. Development was then performed for 30 seconds using a 2.38 mass% TMAH aqueous solution to form a 23 nm hole pattern.

[0896] Using a Hitachi Advanced Technologies Co., Ltd. (CG6300) scanning electron microscope (SEM), the exposure dose when forming a pore size of 23 nm was measured and used as sensitivity. Furthermore, the dimensions of 50 pores were measured at this time, and the standard deviation (σ) calculated from the results was tripled (3σ) to form the dimensional deviation (CDU). The results are shown in Tables 7 and 8.

[0897] [Table 7]

[0898]

[0899] [Table 8]

[0900]

[0901]

[0902] From the results shown in Tables 7 and 8, it was confirmed that the chemically amplified resist composition of the present invention had good sensitivity and excellent CDU.

[0903] [6] Dry etching resistance evaluation

[0904] [Examples 6-1 to 6-20, Comparative Examples 6-1 to 6-10]

[0905] 2 g of each polymer shown in Tables 1 and 2 (polymers P-1 to P-20, comparative polymers CP-1 to CP-10) was dissolved in 10 g of cyclohexanone and filtered with a 0.2 μm filter. The resulting polymer solution was spin-coated on a Si substrate to form a film with a thickness of 300 nm, and evaluated under the following conditions.

[0906] Etching test using CHF3 / CF4 gas system:

[0907] Using a dry etching apparatus TE-8500P manufactured by Tokyo Electron Co., Ltd., the difference in film thickness of the polymer film before and after etching was determined.

[0908] The etching conditions are as follows.

[0909] Chamber pressure 40Pa

[0910] RF power 1000W

[0911] Gap 9mm

[0912] CHF3 gas flow rate 30mL / min

[0913] CF4 gas flow rate 30mL / min

[0914] Ar gas flow rate 100 mL / min

[0915] Time: 60 seconds

[0916] In this evaluation, a smaller difference in film thickness, that is, a smaller amount of reduction, indicates higher etching resistance.

[0917] The results of dry etching resistance are shown in Tables 9 and 10.

[0918] [Table 9]

[0919] polymer <![CDATA[Etching rate of CHF3 / CF4-based gas (nm / min)]]> Example 6-1 P-1 93 Example 6-2 P-2 92 Example 6-3 P-3 94 Example 6-4 P-4 95 Example 6-5 P-5 94 Example 6-6 P-6 95 Examples 6-7 P-7 96 Examples 6-8 P-8 95 Examples 6-9 P-9 94 Examples 6-10 P-10 94 Examples 6-11 P-11 95 Examples 6-12 P-12 93 Examples 6-13 P-13 95 Examples 6-14 P-14 95 Examples 6-15 P-15 94 Examples 6-16 P-16 95 Examples 6-17 P-17 93 Examples 6-18 P-18 95 Examples 6-19 P-19 94 Examples 6-20 P-20 95

[0920] [Table 10]

[0921] polymer <![CDATA[Etching rate of CHF3 / CF4-based gas (nm / min)]]> Comparative Example 6-1 CP-1 115 Comparative Example 6-2 CP-2 119 Comparative Example 6-3 CP-3 100 Comparative Example 6-4 CP-4 99 Comparative Example 6-5 CP-5 112 Comparative Example 6-6 CP-6 113 Comparative Examples 6-7 CP-7 99 Comparative Examples 6-8 CP-8 102 Comparative Examples 6-9 CP-9 112 Comparative Examples 6-10 CP-10 102

[0922] From the results shown in Tables 9 and 10, it can be seen that the polymer of the present invention has excellent dry etching resistance to CHF3 / CF4-based gases.

Claims

1. An onium salt-type monomer represented by the following formula (a): In the formula, n1 is 0 or 1, n2 is an integer from 0 to 4, n3 is 0 or 1, n4 is an integer from 1 to 4, n5 is an integer from 0 to 4, but when n3 is 0, 1≤n4+n5≤4, when n3 is 1, 1≤n4+n5≤6, n6 is 0 or 1, n7 is an integer from 0 to 4, n8 is an integer from 0 to 4, but when n6 is 0, 0≤n7+n8≤4, when n6 is 1, 0≤n7+n8≤6, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R 1 is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, and when n2 is 2, 3 or 4, multiple R 1 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring, R 2 is a halogen atom other than an iodine atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when n5 is 2, 3 or 4, multiple R 2 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring, R 3 is a halogen atom other than a fluorine atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when n8 is 2, 3 or 4, multiple R 3 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring, R F is 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, and when n7 is 2, 3 or 4, each R F They can be the same or different from each other. L A 、L B , and L C 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, X L is a single bond or a alkylene group having 1 to 40 carbon atoms which may contain a heteroatom, Z + Onium cation.

2. The onium salt-type monomer according to claim 1, represented by the following formula (a1): Where, n1~n8, R A 、R 1 、R 2 、R 3 、R F 、L A 、L C and Z + Same as above.

3. The onium salt-type monomer according to claim 2, represented by the following formula (a2): Where, n1~n5, R A 、R 1 、R 2 、L A 、L C and Z + Same as above.

4. The onium salt type monomer according to claim 1, wherein Z + is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2), Where R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom, and R ct1 and R ct2 They may be bonded to each other and to the sulfur atom to which they are bonded to form a ring. 5 . A polymer comprising a repeating unit derived from the onium salt-type monomer according to claim 1 . The polymer according to claim 5 , which functions as a polymer-bound acid generator.

7. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (b1) or (b2), Where R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X 1 represents a single bond, phenylene, naphthylene, *-C(=O)-OX 11 - or *-C(=O)-NH-X 11 -, the phenylene or naphthylene group may be substituted by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group having 1 to 10 carbon atoms which may contain a fluorine atom, 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, wherein the saturated alkylene group may also 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-, * indicates atomic bonds to carbon atoms 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 hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, AL 1 and AL 2 are each independently an acid-labile group, a is an integer from 0 to 4.

8. The polymer according to claim 5, further comprising a repeating unit 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 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-, * represents an atomic bond to a carbon atom of the main chain, 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 hetero atom, and R 12 and R 13 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring, R 14 is 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 hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonthio group having 1 to 20 carbon atoms which may contain a hetero atom, or -N(R 14A )(R 14B ), R 14A and R 14B Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. When b2 is 2 or more, multiple R 14 can be bonded to each other and to the carbon atoms of the aromatic ring to which they are bonded to 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 these groups, X 5 and X 6 are each independently an oxygen atom or a sulfur atom, but X 4 and X 6 Bonded to adjacent carbon atoms of the aromatic ring.

9. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (c1), Where 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-, * represents an atomic bond to a carbon atom of the main chain, R 21 is a halogen atom, a nitro group, a cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, c is an integer of 1 to 4, d is an integer of 0 to 3, but 1≤c+d≤5.

10. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (d1), Where R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, Z 1 represents a single bond, phenylene, naphthylene, *-C(=O)-OZ 11 - or *-C(=O)-NH-Z 11 -, the phenylene or naphthylene group may be substituted by a hydroxyl group, a nitro group, a cyano group, a saturated hydrocarbon group having 1 to 10 carbon atoms which may contain fluorine atoms, an alkoxy group having 1 to 10 carbon atoms which may contain fluorine atoms, or a halogen atom, * represents an atomic bond to 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, wherein the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring, R 31 A group having 1 to 20 carbon atoms, or a hydrogen atom, or a group containing at least one structure selected from the group consisting of a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-). 11 . A chemically amplified resist composition comprising (A) a base polymer comprising the polymer according to claim 5 .

12. The chemically amplified resist composition according to claim 11, further comprising (B) an organic solvent.

13. The chemically amplified resist composition according to claim 11, further comprising (C) a quencher.

14. The chemically amplified resist composition according to claim 11, further comprising (D) another acid generator.

15. The chemically amplified resist composition according to claim 11, further comprising (E) a surfactant.

16. The chemically amplified resist composition according to claim 11, further comprising (F) a dissolution inhibitor.

17. A pattern forming method comprising the steps of: forming a resist film on a substrate using the chemically amplified resist composition according to claim 11; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

18. The pattern forming method according to claim 17, wherein: The high-energy radiation is ArF excimer laser with a wavelength of 193 nm, KrF excimer laser with a wavelength of 248 nm, electron beam, or extreme ultraviolet radiation with a wavelength of 3 to 15 nm.

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