POLYMER, CHEMICALLY Amplified RESIST COMPOSITION AND PATTERN FORMING METHOD

Abstract

The invention relates to a polymer, a chemically amplified resist composition and a pattern forming method. Provided is a polymer that is used in a chemically amplified resist composition that has excellent solvent solubility in optical lithography using high-energy rays, has excellent lithography performance such as high sensitivity, high contrast, EL, LWR, CDU, and DOF, and also has excellent pattern collapse resistance and etching resistance when forming a fine pattern. Also provided are a chemically amplified resist composition containing the polymer, and a pattern forming method using the chemically amplified resist composition. A polymer containing a repeating unit represented by formula (a), and a repeating unit which is derived from an onium salt compound containing a fluorosulfonic acid anion having a polymerizable group and an aromatic ring structure substituted with an iodine atom and which generates an acid when exposed to light. # imgabs0 #

Description

Technical Field

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

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

[0003] As miniaturization progresses and approaches the diffraction limit of light, the contrast of light gradually decreases. Due to the decrease in light contrast, the resolution and focus tolerance of hole patterns and trench patterns in a positive resist film decrease.

[0004] The miniaturization of patterns, as well as the line width roughness (LWR) of line patterns and the critical dimension uniformity (CDU) of hole patterns, are regarded as problems. The effects of the concentration and aggregation of the base polymer and acid generator, and the effect of acid diffusion have been pointed out. Moreover, with the thinning of the resist film, there is a tendency for the LWR to increase, and the deterioration of the LWR due to the thinning accompanying the progress of miniaturization has become a serious problem.

[0005] The resist composition for EUV lithography must achieve high sensitivity, high resolution, and low LWR at the same time. When the acid diffusion distance is shortened, the LWR decreases but the sensitivity decreases. For example, by lowering the post-exposure bake (PEB) temperature, the LWR decreases, but the sensitivity decreases. By increasing the amount of quencher added, the LWR also decreases, but the sensitivity decreases. It is necessary to break the trade-off relationship between sensitivity and LWR.

[0006] In order to suppress acid diffusion, a resist compound containing a repeating unit of an onium salt of a sulfonic acid having a polymerizable unsaturated bond has been proposed (Patent Document 1). Such a so-called polymer-bonded acid generator has the characteristic that a polymer type sulfonic acid is generated by exposure, and thus the acid diffusion is very short. Also, by increasing the ratio of the acid generator, the sensitivity can be improved. When the amount of the additive type acid generator is increased, the sensitivity is improved, but in this case, the acid diffusion distance also increases. Since the acid diffuses unevenly, if the acid diffusion increases, the LWR and CDU deteriorate. In terms of the balance of sensitivity, LWR, and CDU, the polymer type acid generator can be said to have high ability.

[0007] The absorption of EUV with a wavelength of 13.5 nm by iodine atoms is very large. Therefore, the effect of generating secondary electrons from iodine atoms during exposure has been confirmed and is highly regarded in EUV lithography. In Patent Document 2, a photoacid generator in which iodine atoms are introduced into an anion is described, and in Patent Document 3, a photoacid generator containing a polymerizable group in which iodine atoms are introduced into an anion is described. Thereby, it is confirmed that there is an improvement in lithography performance to a certain extent, but the solubility of iodine atoms in organic solvents is not high, and there is a concern of precipitation in the solvent.

[0008] In Patent Documents 4 and 5, a photoresist material using a polymer obtained by copolymerizing salicylic acid having a polymerizable group or its protected form as a base polymer is proposed. Salicylic acid has a structure with a hydroxyl group and a carboxyl group on adjacent carbons of an aromatic ring, and the substituents form hydrogen bonds with each other. Thereby, although there are two polar groups, the solubility in organic solvents is relatively high, and copolymerization with other monomers is relatively easy. However, the performance as a photoresist material is not very ideal, and it is sought to develop a more useful photoresist material for forming fine patterns.

[0009] Prior Art Documents

[0010] Patent Documents

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

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

[0013] [Patent Document 3] Japanese Patent No. 6973274 Gazette

[0014] [Patent Document 4] Japanese Patent Application Laid-Open No. 2023-131926

[0015] [Patent Document 5] International Publication No. 2023 / 162837 Summary of the Invention

[0016] [Problems to be Solved by the Invention]

[0017] In a chemically amplified resist composition using an acid as a catalyst, it is desired to develop a resist composition with higher sensitivity, improved LWR of line patterns and CDU of hole patterns, and excellent etching resistance after pattern formation.

[0018] In view of the foregoing circumstances, an object of the present invention is to provide a polymer for use in a chemically amplified resist composition, a chemically amplified resist composition containing the polymer, and a pattern forming method using the chemically amplified resist composition, which have excellent solvent solubility, high sensitivity, high contrast, and excellent lithography performance such as exposure latitude (EL), LWR, CDU, depth of focus (DOF), etc., especially in optical lithography using high-energy rays such as KrF excimer laser, ArF excimer laser, electron beam (EB), EUV, etc., and are resistant to pattern collapse during fine pattern formation and have excellent etching resistance.

[0019] [Means for Solving the Problem]

[0020] The inventors of the present application have made diligent investigations to achieve the foregoing object, and as a result, it has been found that by using a polymer having a repeating unit derived from an onium salt containing the following as a polymer-bonded acid generator, a chemically amplified resist composition having high sensitivity, improved LWR and CDU, high contrast and high resolution, and excellent etching resistance can be obtained, and thus the present invention has been completed. The onium salt has a styrene or vinylnaphthalene structure as a polymerizable group and contains a fluorosulfonic acid anion having an aromatic ring structure substituted with an iodine atom.

[0021] By using a polymer having a repeating unit containing a cyclic acetal structure fused to an aromatic ring and a repeating unit derived from an onium salt containing a fluorosulfonic acid anion having an aromatic ring structure substituted with an iodine atom as a polymer-bonded acid generator, a chemically amplified resist composition having high sensitivity, improved LWR and CDU, high contrast and high resolution, and excellent etching resistance can be obtained, and thus the present invention has been completed.

[0022] That is, the present invention provides the following polymer, chemically amplified resist composition, and pattern forming method.

[0023] 1. A polymer containing a repeating unit represented by the following formula (a) and

[0024] a repeating unit derived from an onium salt compound containing a fluorosulfonic acid anion having a polymerizable group and an aromatic ring structure substituted with an iodine atom, which generates an acid upon exposure.

[0025] [Chemical Formula 1]

[0026]

[0027] In the formula, m1 is 0 or 1, m2 is an integer of 0 to 3 when m1 is 0, and an integer of 0 to 5 when m1 is 1, and R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0028] X Ais a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents an atomic bond between the carbon atom of the main chain.

[0029] R 1 and R 2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. Further, R 1 and R 2 may also be bonded to each other and together with the carbon atoms to which they are bonded form a ring.

[0030] R 3 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 heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon thio group having 1 to 20 carbon atoms which may contain a heteroatom, or -N(R 3A )(R 3B ). R 3A and R 3B are each independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. When m2 is 2 or more, a plurality of R 3 may also be bonded to each other and together with the carbon atoms of the aromatic ring to which they are bonded form a ring.

[0031] L A is a single bond, an aliphatic alkylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining them.

[0032] L B and L C are each independently an oxygen atom or a sulfur atom. However, L A and L C need to be bonded to adjacent carbon atoms of the aromatic ring.

[0033] 2. The polymer according to 1., wherein L B and L C are both oxygen atoms.

[0034] 3. The polymer according to 1. or 2., wherein L A is a carbonyl group.

[0035] 4. The polymer according to any one of 1. to 3., wherein the repeating unit that generates an acid upon exposure is represented by the following formula (b),

[0036] [Chemical formula 2]

[0037]

[0038] In the formula, n1 is 0 or 1. n2 is 0 or 1. n3 is an integer of 0 to 4. n4 is an integer of 0 to 4. n5 is an integer of 1 to 6. However, when n2 is 0, 1≤n4+n5≤4, and when n2 is 1, 1≤n4+n5≤6. n6 is an integer of 0 to 4. n7 is 0 or 1. n8 is 0 or 1.

[0039] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0040] R 11 is a halogen atom, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonthio group having 1 to 20 carbon atoms which may contain a hetero atom. 11 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring.

[0041] R 12 is a halogen atom other than an iodine atom, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonthio group having 1 to 20 carbon atoms which may contain a hetero atom. 12 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring.

[0042] L D , L E and L F Each is independently a single bond, an ether bond, an ester bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond.

[0043] X L It is a single bond or a alkylene group having 1 to 40 carbon atoms which may contain a hetero atom.

[0044] Q 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0045] Q 3 and Q 4 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0046] Z + It is an onium cation.

[0047] 5. The polymer according to any one of 1. to 4., wherein the repeating unit represented by formula (b) is represented by the following formula (b1),

[0048] [Chemistry 3]

[0049]

[0050] In the formula, R A , R 11 , R 12 , L D , L F , Q 1 ~Q 4 , n1 to n6 and Z + are as described above.

[0051] 6. The polymer according to 5., wherein the repeating unit represented by formula (b1) is represented by the following formula (b2),

[0052] [Chemical formula 4]

[0053]

[0054] In the formula, R A , R 11 , R 12 , L D , Q 1 , Q 2 , n1 to n6 and Z + are as described above.

[0055] 7. The polymer according to any one of 1. to 6., wherein Z + is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2),

[0056] [Chemical formula 5]

[0057]

[0058] In the formula, R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may also contain a heteroatom. Further, R ct1 and R ct2 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

[0059] 8. The polymer according to any one of 1. to 7., further containing a repeating unit represented by the following formula (c1),

[0060] [Chemical formula 6]

[0061]

[0062] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0063] X 1is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond with a carbon atom of the main chain.

[0064] R 21 is a halogen atom, nitro group, cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom.

[0065] a is an integer of 1 to 4. b is an integer of 0 to 3. However, 1 ≤ a + b ≤ 5.

[0066] 9. The polymer according to any one of 1. to 8. further contains a repeating unit represented by the following formula (d1) or (d2),

[0067] [Chemical formula 7]

[0068]

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

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

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

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

[0073] AL 1 and AL 2 are each independently an acid-labile group.

[0074] R 31 is a halogen atom, cyano group, hydroxyl group, nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a hetero atom, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms which may contain a hetero atom or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a hetero atom.

[0075] c is an integer from 0 to 4.

[0076] 10. The polymer according to any one of 1. to 9. further contains a repeating unit represented by the following formula (e1).

[0077] [Chemical formula 8]

[0078]

[0079] In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0080] Z 1 is a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-Z 11 -, or *-C(=O)-NH-Z 11 -. The phenylene group or naphthylene group may also be substituted with a hydroxyl group, a nitro group, a cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. * represents an atomic bond between the carbon atom of the main chain. Z 11 is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring.

[0081] R 41 is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one or more structures selected from hydroxyl groups other than phenolic hydroxyl groups, cyano groups, carbonyl groups, carboxyl groups, ether bonds, ester bonds, sulfonate ester bonds, carbonate ester bonds, lactone rings, sultone rings and carboxylic anhydrides (-C(=O)-O-C(=O)-).

[0082] 11. A chemically amplified resist composition comprising (A) a base polymer containing the polymer according to any one of 1. to 10.

[0083] 12. The chemically amplified resist composition according to 11. further comprises (B) a quencher.

[0084] 13. The chemically amplified resist composition according to 11. or 12. further comprises (C) an organic solvent.

[0085] 14. The chemically amplified resist composition according to any one of 11. to 13. further comprises (D) an acid generator.

[0086] 15. The chemically amplified resist composition according to any one of 11. to 14. further comprises (E) a surfactant.

[0087] 16. The chemically amplified resist composition according to any one of 11. to 15. further comprises (F) a dissolution inhibitor.

[0088] 17. A pattern forming method comprising the following steps:

[0089] Forming a resist film on a substrate using a chemically amplified resist composition according to any one of 11. to 16.,

[0090] Exposing the aforementioned resist film to high-energy rays, and

[0091] Developing the exposed resist film using a developer.

[0092] 18. The pattern forming method according to 17., wherein

[0093] The aforementioned high-energy rays are an ArF excimer laser with a wavelength of 193 nm, a KrF excimer laser with a wavelength of 248 nm, an electron beam, or extreme ultraviolet rays with a wavelength of 3 to 15 nm.

[0094] [Effects of the Invention]

[0095] A polymer containing a repeating unit represented by formula (a) and a repeating unit that generates an acid from an onium salt compound containing a fluorosulfonic acid anion having a polymerizable group and an aromatic ring structure substituted with an iodine atom has good solvent solubility and a large atomic weight of the iodine atom, and has a structure in which the generated acid is bonded to the polymer main chain. Therefore, it has the characteristic of small acid diffusion. Thereby, it is possible to prevent a decrease in resolution due to blurring caused by acid diffusion, and it is possible to improve LWR and CDU. Also, due to the very large absorption of EUV with a wavelength of 13.5 nm by the iodine atom, secondary electrons are generated from the iodine atom during exposure and the sensitivity is increased. Thereby, the sensitivity is high, and a chemically amplified resist composition with improved LWR and CDU can be constructed. Also, the repeating unit represented by formula (a) has an acid-labile structure derived from a cyclic acetal, and a deprotection reaction proceeds due to the action of an acid, generating two polar groups. Thereby, the contrast between the exposed portion and the unexposed portion is increased. Furthermore, the aromatic ring in the repeating unit acts as a good etching resistance group and is suitable for forming fine patterns. Detailed Description of the Invention

[0096] [Polymer]

[0097] The polymer of the present invention contains a repeating unit represented by the following formula (a) (hereinafter also referred to as repeating unit a).

[0098] [Chemical Formula 9]

[0099]

[0100] In formula (a), m1 is 0 or 1. When m1 is 0, it is a benzene ring, and when m1 is 1, it is a naphthalene ring. However, from the perspective of solvent solubility, a benzene ring with m1 = 0 is preferred. When m1 is 0, m2 is an integer from 0 to 3, and when m1 is 1, m2 is an integer from 0 to 5. From the perspective of raw material availability, m2 being 0, 1, 2, or 3 is preferred, and 0, 1, or 2 is more preferred.

[0101] In formula (a), R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom and a methyl group are preferred, and a hydrogen atom is more desirable.

[0102] In formula (a), X A is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond between an atom and a carbon atom of the main chain. Among these, a single bond and *-C(=O)-O- are preferred, and a single bond is more desirable.

[0103] In formula (a), R 1 and R 2 are each independently a hydrogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl; cycloaliphatic saturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl; alkenyl groups having 2 to 20 carbon atoms such as vinyl, allyl, propenyl, butenyl, hexenyl; cycloaliphatic unsaturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms such as phenyl, naphthyl; aralkyl groups having 7 to 20 carbon atoms such as benzyl, 1-phenylethyl, 2-phenylethyl; groups obtained by combining them, etc. Further, some or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and a part of -CH 2 - of the aforementioned hydrocarbon group may also be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0104] Further, R 1 and R 2They can also be bonded to each other and together with the carbon atoms to which they are bonded form a ring. For specific examples of the aforementioned rings, for example, a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. Further, part or all of the hydrogen atoms in the aforementioned ring may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and part of the -CH 2 - in the aforementioned ring may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may also contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0105] In formula (a), R 3 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 heteroatom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbonthio group having 1 to 20 carbon atoms which may contain a heteroatom, or -N(R 3A )(R 3B ). R 3A and R 3B are each independently a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. The aforementioned halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, more preferably a fluorine atom or an iodine atom. The hydrocarbon moieties of the aforementioned hydrocarbon group, hydrocarbonoxy group, hydrocarbonoxycarbonyl group and hydrocarbonthio group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof are, for example, the same examples as those exemplified for the hydrocarbon group represented by R 1 and R 2 . Further, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and part of the -CH 2 - in the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may also contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. When m2 is 2 or more, each R 3 may be the same or different from each other.

[0106] Further, when m2 is 2 or more, a plurality of R 3They can also be bonded to each other and together with the carbon atoms of the aromatic rings to which they are bonded to form a ring. Specific examples of the rings formed in this case include, for example, a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. Further, part or all of the hydrogen atoms in the aforementioned rings may be substituted with groups containing heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and part of -CH 2 - in the aforementioned rings may also be substituted with groups containing heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0107] In formula (a), L A is a single bond, an aliphatic alkylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining them. Among these, from the viewpoint of raw material procurement, a single bond, a carbonyl group, or a sulfonyl group is preferred, and from the viewpoint of the polar group generated after the reaction, a single bond or a carbonyl group is more preferred.

[0108] In formula (a), L B and L C are each independently an oxygen atom or a sulfur atom. However, L A and L C need to be bonded to adjacent carbon atoms of the aromatic ring. L B and L C may be the same or different from each other, and from the viewpoint of reactivity, it is preferred that both L B and L C are oxygen atoms.

[0109] Specific examples of the repeating unit a are listed below, but are not limited to these. Further, in the following formula, R A is as described above. Also, the bonding positions of various substituents on the aromatic ring may be exchanged with each other.

[0110] [Chemical formula 10]

[0111]

[0112] [Chemical formula 11]

[0113]

[0114] [Chemical formula 12]

[0115]

[0116] [Chemical formula 13]

[0117]

[0118] [Chemical formula 14]

[0119]

[0120] [Chemical Formula 15]

[0121]

[0122] [Chemical Formula 16]

[0123]

[0124] [Chemical Formula 17]

[0125]

[0126] [Chemical Formula 18]

[0127]

[0128] [Chemical Formula 19]

[0129]

[0130] [Chemical Formula 20]

[0131]

[0132] [Chemical Formula 21]

[0133]

[0134] [Chemical Formula 22]

[0135]

[0136] [Chemical Formula 23]

[0137]

[0138] [Chemical Formula 24]

[0139]

[0140] [Chemical Formula 25]

[0141]

[0142] [Chemical Formula 26]

[0143]

[0144] [Chemical Formula 27]

[0145]

[0146] [Chemical Formula 28]

[0147]

[0148] [Chemical formula 29]

[0149]

[0150] [Chemical formula 30]

[0151]

[0152] [Chemical formula 31]

[0153]

[0154] [Chemical formula 32]

[0155]

[0156] [Chemical formula 33]

[0157]

[0158] [Chemical formula 34]

[0159]

[0160] [Chemical formula 35]

[0161]

[0162] [Chemical formula 36]

[0163]

[0164] [Chemical formula 37]

[0165]

[0166] [Chemical formula 38]

[0167]

[0168] [Chemical formula 39]

[0169]

[0170] [Chemical formula 40]

[0171]

[0172] [Chemical formula 41]

[0173]

[0174] [Chemical formula 42]

[0175]

[0176] [Chemical formula 43]

[0177]

[0178] [Chemical formula 44]

[0179]

[0180] [Chemical formula 45]

[0181]

[0182] [Chemical formula 46]

[0183]

[0184] [Chemical formula 47]

[0185]

[0186] [Chemical formula 48]

[0187]

[0188] [Chemical formula 49]

[0189]

[0190] [Chemical formula 50]

[0191]

[0192] [Chemical formula 51]

[0193]

[0194] [Chemical formula 52]

[0195]

[0196] [Chemical formula 53]

[0197]

[0198] [Chemical formula 54]

[0199]

[0200] [Chemical formula 55]

[0201]

[0202] [Chemical formula 56]

[0203]

[0204] [Chemical formula 57]

[0205]

[0206] [Chemical formula 58]

[0207]

[0208] [Chemical formula 59]

[0209]

[0210] The polymer of the present invention is characterized by further containing an onium salt compound derived from a fluorosulfonic acid anion containing a polymerizable group and an aromatic ring structure substituted with an iodine atom, and a repeating unit that generates an acid upon exposure (hereinafter also referred to as repeating unit b). Repeating unit b is preferably represented by the following formula (b).

[0211] [Chemical formula 60]

[0212]

[0213] In formula (b), 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 viewpoint of solvent solubility, a benzene ring with n1 = 0 is preferred. n2 is 0 or 1. When n2 is 0, it is a benzene ring, and when n2 is 1, it is a naphthalene ring. From the viewpoint of solvent solubility, a benzene ring with n2 = 0 is preferred. n3 is an integer from 0 to 4. From the viewpoint of raw material procurement, n3 is preferably 0, 1, or 2, and 0 or 1 is more ideal. n4 is an integer from 0 to 4, preferably 0, 1, 2, or 3, more preferably 0, 1, or 2, and most preferably 0 or 1. n5 is an integer from 1 to 6. The more the number of iodine atoms in the anion structure, the higher the absorption of EUV in particular, but the solvent solubility will be lacking, and there is a concern of precipitation in the resist composition. Therefore, n5 is preferably 1, 2, or 3, and 1 or 2 is more preferred. However, when n2 = 0, 1 ≤ n4 + n5 ≤ 4, and when n2 = 1, 1 ≤ n4 + n5 ≤ 6. n6 is an integer from 0 to 4, preferably 0, 1, 2, or 3, and more preferably 1. n7 is 0 or 1. n8 is 0 or 1.

[0214] In formula (b), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom and a methyl group are preferred, and a hydrogen atom is more preferred.

[0215] In formula (b), the iodine atom in the aromatic ring of the anion is preferably bonded to the carbon atom adjacent to the carbon atom to which L E is bonded. Since the iodine atom is an element with a large atomic radius, the rotation of the bonding axes of the aromatic ring to which the polymerizable group is bonded and the aromatic ring to which the iodine atom is bonded is inhibited, and the rigidity of the polymer is increased.

[0216] In formula (b), R11 is a halogen atom, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may also contain a heteroatom, or a hydrocarbon thio group having 1 to 20 carbon atoms which may also contain a heteroatom. The aforementioned halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, more preferably a fluorine atom or an iodine atom. The hydrocarbon moiety of the aforementioned hydrocarbon group, hydrocarbon oxy group and hydrocarbon thio group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl; cycloaliphatic saturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl; alkenyl groups having 2 to 20 carbon atoms such as vinyl, allyl, propenyl, butenyl, hexenyl; cycloaliphatic unsaturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms such as phenyl, naphthyl; aralkyl groups having 7 to 20 carbon atoms such as benzyl, 1-phenylethyl, 2-phenylethyl; groups obtained by combining them, etc. Further, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and a part of -CH 2 - of the aforementioned hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. When n3 is 2, 3 or 4, each R 11 may be the same or different from each other.

[0217] Further, when n3 is 2, 3 or 4, a plurality of R 11 may also be bonded to each other and form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed at this time include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. Further, part or all of the hydrogen atoms in the aforementioned ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and a part of -CH 2 - of the aforementioned ring may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, and as a result, it may also contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0218] In formula (b), R 12is a halogen atom other than an iodine atom, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbon thio group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of the halogen atom other than the iodine atom include, for example, a fluorine atom, a chlorine atom, a bromine atom, etc. The hydrocarbon moieties of the aforementioned hydrocarbon group, hydrocarbon oxy group, and hydrocarbon thio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof are the same as the examples exemplified for the hydrocarbon group represented by R 11 but are not limited thereto. When n4 is 2, 3, or 4, each R 12 may be the same or different from each other.

[0219] Further, when n4 is 2, 3, or 4, a plurality of R 12 may also be bonded to each other and form a ring together with the carbon atoms to which they are bonded. The aforementioned ring is preferably a 5- to 8-membered ring.

[0220] In formula (b), L D , L E and L F are each independently a single bond, an ether bond, an ester bond, a sulfonate bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. Among these, L D is preferably a single bond, an ether bond, an ester bond, or a sulfonate bond, more preferably an ester bond or a sulfonate bond. L E is preferably a single bond, an ether bond, or an ester bond, more preferably a single bond. L F is preferably a single bond, an ether bond, an ester bond, or a sulfonate bond, more preferably an ether bond or an ester bond.

[0221] In formula (b), X L is a single bond, or an alkylene group having 1 to 40 carbon atoms which may contain a heteroatom. The aforementioned alkylene group may be linear, branched, or cyclic, and specific examples thereof include, for example, alkanediyl, cycloaliphatic saturated alkylene groups, etc. Specific examples of the aforementioned heteroatom include, for example, an oxygen atom, a nitrogen atom, a sulfur atom, etc.

[0222] Specific examples of the alkylene group having 1 to 40 carbon atoms which may contain a heteroatom represented by X L are listed below, but are not limited thereto. Further, in the following formula, * is each a bond to the atoms of L D and L E .

[0223] [Chemical formula 61]

[0224]

[0225] [Chemical formula 62]

[0226]

[0227] [Chemical formula 63]

[0228]

[0229] [Chemical formula 64]

[0230]

[0231] Among these, X L -0 to X L -22, X L -29 to X L -34, and X L -47 to X L -58 is preferable.

[0232] In formula (b), Q 1 and Q 2 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms is preferably a trifluoromethyl group.

[0233] In formula (b), Q 3 and Q 4 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms is preferably a trifluoromethyl group. Q 3 and Q 4 being a fluorine atom is more preferable.

[0234] In formula (b), -[C(Q 1 )(Q 2 )] n6 -C(Q 3 )(Q 4 )-SO 3 - Specific examples of the partial structure represented are preferably as shown below, but are not limited to these. Also, in the following formula, * represents a bond with the atom of L F

[0235] [Chemical formula 65]

[0236]

[0237] Among these, Acid-1 to Acid-7 are more preferable, and Acid-1 to Acid-3, Acid-6, and Acid-7 are even more preferable.

[0238] The repeating unit b is preferably represented by the following formula (b1).

[0239] [Chemical formula 66]

[0240]

[0241] In the formula, R A , R 11 , R​12 , L D , L F , Q 1 ~Q 4 , n1 to n6 and Z + As described above.

[0242] The repeating unit represented by formula (b1) is preferably the one represented by the following formula (b2).

[0243] [Chemical formula 67]

[0244]

[0245] In the formula, R A , R 11 , R 12 , L D , Q 1 , Q 2 , n1 to n6 and Z + As described above.

[0246] Anions of the monomers that give repeating unit b are listed below, but are not limited to these. Also, in the following formula, R A , Q 1 , R 12 , n4 and n5 are as described above. Also, the bonding positions of various substituents on the aromatic ring can be exchanged with each other.

[0247] [Chemical formula 68]

[0248]

[0249] [Chemical formula 69]

[0250]

[0251] [Chemical formula 70]

[0252]

[0253] [Chemical formula 71]

[0254]

[0255] [Chemical formula 72]

[0256]

[0257] [Chemical formula 73]

[0258]

[0259] [Chemical formula 74]

[0260]

[0261] [Chemical Formula 75]

[0262]

[0263] [Chemical Formula 76]

[0264]

[0265] [Chemical Formula 77]

[0266]

[0267] [Chemical Formula 78]

[0268]

[0269] [Chemical Formula 79]

[0270]

[0271] [Chemical Formula 80]

[0272]

[0273] [Chemical Formula 81]

[0274]

[0275] [Chemical Formula 82]

[0276]

[0277] [Chemical Formula 83]

[0278]

[0279] [Chemical Formula 84]

[0280]

[0281] [Chemical Formula 85]

[0282]

[0283] [Chemical Formula 86]

[0284]

[0285] [Chemical Formula 87]

[0286]

[0287] [Chemical Formula 88]

[0288]

[0289] [Chemical formula 89]

[0290]

[0291] [Chemical formula 90]

[0292]

[0293] [Chemical formula 91]

[0294]

[0295] [Chemical formula 92]

[0296]

[0297] [Chemical formula 93]

[0298]

[0299] [Chemical formula 94]

[0300]

[0301] [Chemical formula 95]

[0302]

[0303] [Chemical formula 96]

[0304]

[0305] [Chemical formula 97]

[0306]

[0307] [Chemical formula 98]

[0308]

[0309] [Chemical formula 99]

[0310]

[0311] [Chemical formula 100]

[0312]

[0313] [Chemical formula 101]

[0314]

[0315] [Chemical formula 102]

[0316]

[0317] [Chemical formula 103]

[0318]

[0319] [Chemical Formula 104]

[0320]

[0321] [Chemical Formula 105]

[0322]

[0323] [Chemical Formula 106]

[0324]

[0325] [Chemical Formula 107]

[0326]

[0327] [Chemical Formula 108]

[0328]

[0329] [Chemical Formula 109]

[0330]

[0331] [Chemical Formula 110]

[0332]

[0333] [Chemical Formula 111]

[0334]

[0335] [Chemical Formula 112]

[0336]

[0337] [Chemical Formula 113]

[0338]

[0339] [Chemical Formula 114]

[0340]

[0341] [Chemical Formula 115]

[0342]

[0343] [Chemical Formula 116]

[0344]

[0345] [Chemical Formula 117]

[0346]

[0347] [Chemical Formula 118]

[0348]

[0349] [Chemical Formula 119]

[0350]

[0351] [Chemical Formula 120]

[0352]

[0353] [Chemical Formula 121]

[0354]

[0355] [Chemical Formula 122]

[0356]

[0357] [Chemical Formula 123]

[0358]

[0359] [Chemical Formula 124]

[0360]

[0361] [Chemical Formula 125]

[0362]

[0363] [Chemical Formula 126]

[0364]

[0365] [Chemical Formula 127]

[0366]

[0367] [Chemical Formula 128]

[0368]

[0369] [Chemical Formula 129]

[0370]

[0371] [Chemical Formula 130]

[0372]

[0373] [Chemical Formula 131]

[0374]

[0375] [Chemical Formula 132]

[0376]

[0377] [Chemical Formula 133]

[0378]

[0379] [Chemical Formula 134]

[0380]

[0381] [Chemical Formula 135]

[0382]

[0383] [Chemical Formula 136]

[0384]

[0385] [Chemical Formula 137]

[0386]

[0387] [Chemical Formula 138]

[0388]

[0389] [Chemical Formula 139]

[0390]

[0391] [Chemical Formula 140]

[0392]

[0393] [Chemical Formula 141]

[0394]

[0395] [Chemical Formula 142]

[0396]

[0397] [Chemical Formula 143]

[0398]

[0399] Examples of other anions include the anions described in paragraphs

[0023] to

[0029] of Japanese Patent No. 6973274.

[0400] In formula (b), Z+ is an onium cation. It is preferably a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2).

[0401] [Chemical formula 144]

[0402]

[0403] In formulas (cation-1) and (cation-2), R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom.

[0404] R ct1 ~R ct5 Specific examples of the halogen atom represented include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.

[0405] R ct1 ~R ct5 The hydrocarbon group represented 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 a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group; cycloaliphatic saturated hydrocarbon groups having 3 to 30 carbon atoms such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, an adamantyl group; alkenyl groups having 2 to 30 carbon atoms such as a vinyl group, an allyl group, a propenyl group, a butenyl group, a hexenyl group; cycloaliphatic unsaturated hydrocarbon groups having 3 to 30 carbon atoms such as a cyclohexenyl group; aryl groups having 6 to 30 carbon atoms such as a phenyl group, a naphthyl group, a thienyl group; aralkyl groups having 7 to 30 carbon atoms such as a benzyl group, a 1-phenylethyl group, a 2-phenylethyl group; groups obtained by combining them, etc., and an aryl group is preferred. Further, a part or all of the hydrogen atoms of the hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and a part of -CH 2 - may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0406] Further, R ct1 and R ct2 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. Specific examples of the structure of the ring in this case include those represented by the following formula, etc.

[0407] [Chemical formula 145]

[0408]

[0409] In the formula, the chain line is the atomic bond of and R ct3 and

[0410] Specific examples of the sulfonium cation represented by formula (cation-1) are listed below, but are not limited to these.

[0411] [Chemical formula 146]

[0412]

[0413] [Chemical formula 147]

[0414]

[0415] [Chemical formula 148]

[0416]

[0417] [Chemical formula 149]

[0418]

[0419] [Chemical formula 150]

[0420]

[0421] [Chemical formula 151]

[0422]

[0423] [Chemical formula 152]

[0424]

[0425] [Chemical formula 153]

[0426]

[0427] [Chemical formula 154]

[0428]

[0429] [Chemical formula 155]

[0430]

[0431] [Chemical formula 156]

[0432]

[0433] [Chemical formula 157]

[0434]

[0435] [Chemical formula 158]

[0436]

[0437] [Chemical Formula 159]

[0438]

[0439] [Chemical Formula 160]

[0440]

[0441] [Chemical Formula 161]

[0442]

[0443] [Chemical Formula 162]

[0444]

[0445] [Chemical Formula 163]

[0446]

[0447] [Chemical Formula 164]

[0448]

[0449] [Chemical Formula 165]

[0450]

[0451] [Chemical Formula 166]

[0452]

[0453] [Chemical Formula 167]

[0454]

[0455] [Chemical Formula 168]

[0456]

[0457] [Chemical Formula 169]

[0458]

[0459] [Chemical Formula 170]

[0460]

[0461] [Chemical Formula 171]

[0462]

[0463] [Chemical Formula 172]

[0464]

[0465] Specific examples of the sulfonium cation represented by formula (cation-2) are listed below, but are not limited to these.

[0466] [Chemical formula 173]

[0467]

[0468] [Chemical formula 174]

[0469]

[0470] Specific examples of the repeating unit b are any combination of the aforementioned anions and cations.

[0471] The monomer that gives the repeating unit b can be synthesized, for example, in the same manner as the sulfonium salt having a polymerizable anion described in Japanese Patent No. 5201363, but is not limited thereto.

[0472] The polymer of the present invention is a polymer-bonded photoacid generator that acts as a base polymer and also as a photoacid generator in a chemically amplified resist composition. The structural features of the polymer of the present invention, for example, contain a repeating unit a having a cyclic acetal structure fused to an aromatic ring and a repeating unit b derived from an onium salt compound containing a fluorosulfonic acid anion having a polymerizable group and an aromatic ring structure substituted with an iodine atom, and generate an acid upon exposure. The cyclic acetal structure fused to the aromatic ring has good solvent solubility and also acts as an acid-labile group. Thereby, a deprotection reaction proceeds due to the action of an acid and two polar groups are generated. Thereby, the contrast between the exposed portion and the unexposed portion is improved. Further, the iodine atom contained in the repeating unit b has a large absorption for EUV of a wavelength of 13.5 nm. Therefore, secondary electrons are generated during exposure, and the energy of the secondary electrons moves to the photoacid generator, so that decomposition is promoted, and thereby the sensitivity is improved. The polymerizable group having a styrene or vinylnaphthalene structure is more rigid than a polymerizable group such as methacrylate, and raises the glass transition temperature (Tg) of the polymer. The aromatic rings within the base polymer or between the base polymers are regularly arranged correctly by an interaction (π-π stacking effect), and it is considered that when forming a fine pattern, it shows resistance to pattern collapse against a developer. Further, in the etching step after forming the fine pattern, excellent etching resistance is exhibited by having an aromatic ring directly bonded to the main chain. Although there is a concern that the iodine atom has poor solvent solubility, since the cyclic acetal structure contained in the repeating unit a of the polymer before exposure has high solvent solubility, precipitation in a solvent, etc. are suppressed, and after exposure, when developed with an alkaline developer, the polar groups generated after deprotection of the acetal structure have high affinity for the alkaline developer, so the exposed portion can be effectively removed. Thereby, the risk of development defects can be reduced. By these synergistic effects, when the polymer of the present invention is used as a base polymer in a chemically amplified resist composition, a pattern excellent in LWR of a line pattern and CDU of a hole pattern and resistant to pattern collapse can be formed. The polymer of the present invention is particularly suitable as a material for a chemically amplified positive resist composition.

[0473] It is preferable that the aforementioned polymer further contains a repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit c).

[0474] [Chemical 175]

[0475]

[0476] In formula (c1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. X 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond between a carbon atom of the main chain. R 21is a halogen atom, nitro group, cyano group, a hydrocarbon group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain heteroatoms, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain heteroatoms, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms which may contain heteroatoms, or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain heteroatoms. a is an integer of 1 to 4. b is an integer of 0 to 3. However, 1 ≤ a + b ≤ 5.

[0477] Specific examples of the repeating unit c are listed below, but are not limited to these. Also, in the following formula, R A As described above.

[0478] [Chemical formula 176]

[0479]

[0480] [Chemical formula 177]

[0481]

[0482] [Chemical formula 178]

[0483]

[0484] [Chemical formula 179]

[0485]

[0486] [Chemical formula 180]

[0487]

[0488] The aforementioned polymer may further contain a repeating unit represented by the following formula (d1) (hereinafter also referred to as repeating unit d1) or a repeating unit represented by the following formula (d2) (hereinafter also referred to as repeating unit d2).

[0489] [Chemical formula 181]

[0490]

[0491] In the formulas (d1) and (d2), R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0492] In the formula (d1), Y 1 is a single bond, phenylene, naphthylene, *-C(=O)-O-Y 11 -, or *-C(=O)-NH-Y 11 ]-, and the phenylene or naphthylene may also be substituted with a hydroxyl group, nitro group, cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain fluorine atoms, or a halogen atom. Y 11is a saturated alkylene group, phenylene group or naphthylene group having 1 to 10 carbon atoms, and the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. * represents an atomic bond with a carbon atom of the main chain.

[0493] In formula (d2), Y 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond with a carbon atom of the main chain. R 31 is a halogen atom, a cyano group, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon oxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon carbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom or a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. c is an integer of 0 to 4, preferably 0 or 1.

[0494] In formulas (d1) and (d2), AL 1 and AL 2 are each independently an acid-labile group. Specific examples of the acid-labile group are, for example, those described in JP-A-2013-80033 and JP-A-2013-83821, but are not limited thereto.

[0495] Generally, specific examples of the acid-labile group are represented by the following formulas (AL-1) to (AL-3).

[0496] [Chemical formula 182]

[0497]

[0498] In the formula, * is an atomic bond.

[0499] In formulas (AL-1) and (AL-2), R L1 and R L2 are each independently a hydrocarbon group having 1 to 40 carbon atoms, and may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom or an iodine atom. The hydrocarbon group may be linear, branched or cyclic. The hydrocarbon group is preferably one having 1 to 20 carbon atoms.

[0500] In formula (AL-1), d is an integer of 0 to 10, preferably an integer of 1 to 5.

[0501] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom or an iodine atom. The hydrocarbon group may be linear, branched or cyclic. Also, R L2 , R L3 and R L4Any two of them may also be bonded to each other and together with the carbon atoms or carbon and oxygen atoms to which they are bonded form a ring having 3 to 20 carbon atoms. It is more preferable that the aforementioned ring has 4 to 16 carbon atoms, and an alicyclic ring is particularly preferable.

[0502] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbon group having 1 to 20 carbon atoms, and may also contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, and an iodine atom. The aforementioned hydrocarbon group may be linear, branched, or cyclic. Also, any two of R L5 , R L6 and R L7 may also 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. It is more preferable that the aforementioned ring has 4 to 16 carbon atoms, and an alicyclic ring is particularly preferable.

[0503] Specific examples of the repeating unit d1 are listed below, but are not limited to these. Also, in the following formula, R A and AL 1 are as described above.

[0504] [Chemical formula 183]

[0505]

[0506] [Chemical formula 184]

[0507]

[0508] [Chemical formula 185]

[0509]

[0510] [Chemical formula 186]

[0511]

[0512] [Chemical formula 187]

[0513]

[0514] [Chemical formula 188]

[0515]

[0516] [Chemical formula 189]

[0517]

[0518] Specific examples of the repeating unit d2 are listed below, but are not limited to these. Also, in the following formula, R A and AL 2 are as described above.

[0519] [Chemical formula 190]

[0520]

[0521] [Chemical formula 191]

[0522]

[0523] [Chemical formula 192]

[0524]

[0525] It is preferred that the aforementioned polymer further contains a repeating unit represented by the following formula (e1) (hereinafter also referred to as repeating unit e).

[0526] [Chemical formula 193]

[0527]

[0528] In formula (e1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Z 1 is a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-Z 11 - or *-C(=O)-NH-Z 11 -, and the phenylene group or naphthylene group may also be substituted by a hydroxyl group, a nitro group, a cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. * represents an atomic bond between the carbon atom of the main chain. Z 11 is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. R 41 is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one or more structures selected from hydroxyl groups other than phenolic hydroxyl groups, cyano groups, carbonyl groups, carboxyl groups, ether bonds, ester bonds, sulfonate ester bonds, carbonate ester bonds, lactone rings, sultone rings and carboxylic anhydrides (-C(=O)-O-C(=O)-).

[0529] Specific examples of the repeating unit e are listed below, but are not limited to these. Also, in the following formula, R A is as described above.

[0530] [Chemical formula 194]

[0531]

[0532] [Chemical formula 195]

[0533]

[0534] [Chemical formula 196]

[0535]

[0536] [Chemical Formula 197]

[0537]

[0538] [Chemical Formula 198]

[0539]

[0540] [Chemical Formula 199]

[0541]

[0542] [Chemical Formula 200]

[0543]

[0544] [Chemical Formula 201]

[0545]

[0546] [Chemical Formula 202]

[0547]

[0548] [Chemical Formula 203]

[0549]

[0550] [Chemical Formula 204]

[0551]

[0552] [Chemical Formula 205]

[0553]

[0554] [Chemical Formula 206]

[0555]

[0556] [Chemical Formula 207]

[0557]

[0558] [Chemical Formula 208]

[0559]

[0560] [Chemical Formula 209]

[0561]

[0562] Regarding the repeating unit e, in the case of ArF lithography, those having a lactone ring as a polar group are particularly preferable, and in the case of KrF lithography, EB lithography, and EUV lithography, those having a phenol moiety are more preferable.

[0563] The aforementioned polymer may further contain a repeating unit having a structure in which a hydroxyl group is protected by an acid-labile group (hereinafter also referred to as repeating unit f). The repeating unit f 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 by the action of an acid to generate a hydroxyl group, and those represented by the following formula (f1) are preferable.

[0564] [Chemical formula 210]

[0565]

[0566] In formula (f1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 51 is an (e + 1)-valent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. R 52 is an acid-labile group. e is an integer of 1 to 4.

[0567] In formula (f1), the acid-labile group represented by R 52 is not particularly limited as long as it is deprotected by the action of an acid to generate a hydroxyl group. The structure of R 52 is not particularly limited, and an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (f2), etc. are preferable, and an alkoxymethyl group represented by the following formula (f2) is particularly preferable.

[0568] [Chemical formula 211]

[0569]

[0570] In the formula, * represents an atomic bond. R 53 is a hydrocarbon group having 1 to 15 carbon atoms.

[0571] R 52 The specific examples of the acid-labile group represented by, the alkoxymethyl group represented by formula (f2), and the repeating unit e are the same as those exemplified in the description of the repeating unit d in Japanese Patent Application Laid-Open No. 2020-111564, for example.

[0572] The aforementioned polymer may further contain a repeating unit g derived from indene, benzofuran, benzothiophene, vinylnaphthalene, chromone, coumarin, norbornadiene, or derivatives thereof. Specific examples of the monomer providing the repeating unit g are listed below, but are not limited to these.

[0573] [Chemical formula 212]

[0574]

[0575] The aforementioned polymer may further contain repeating unit h derived from styrene, indene, vinylpyridine, or vinylcarbazole.

[0576] In the polymer of the present invention, the content ratios of repeating units a, b, c, d1, d2, e, f, g, and h are preferably 0 < a ≤ 0.6, 0 < b ≤ 0.4, 0 ≤ c ≤ 0.8, 0 ≤ d1 ≤ 0.6, 0 ≤ d2 ≤ 0.6, 0 ≤ e ≤ 0.6, 0 ≤ f ≤ 0.3, 0 ≤ g ≤ 0.3, and 0 ≤ h ≤ 0.3, more preferably 0 < a ≤ 0.5, 0 < b ≤ 0.3, 0 < c ≤ 0.7, 0 ≤ d1 ≤ 0.6, 0 ≤ d2 ≤ 0.5, 0 ≤ e ≤ 0.5, 0 ≤ f ≤ 0.2, 0 ≤ g ≤ 0.2, and 0 ≤ h ≤ 0.2. However, a + b + c + d1 + d2 + e + f + g + h ≤ 1.0.

[0577] The weight-average molecular weight (Mw) of the aforementioned polymer is preferably from 1000 to 500000, more preferably from 3000 to 100000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no concern about a decrease in resolution caused by an inability to ensure the difference in dissolution rate before and after exposure. Also, in the present invention, Mw is a polystyrene-converted measured value obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent.

[0578] Furthermore, with the pattern rule being miniaturized, the influence of the molecular weight distribution (Mw / Mn) of the aforementioned polymer tends to increase. Therefore, in order to obtain a resist composition suitable for use with a fine pattern size, a narrow dispersion with Mw / Mn of 1.0 to 2.0 is preferred. If it is within the aforementioned range, there are fewer low-molecular-weight and high-molecular-weight polymers, and there is no concern about foreign matter appearing on the pattern or the shape of the pattern deteriorating after exposure.

[0579] The method for synthesizing the aforementioned polymer is, for example, a method of adding a radical polymerization initiator to monomers providing the aforementioned repeating units in an organic solvent and heating to polymerize them.

[0580] Specific examples of the organic solvents 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), and the like. Specific examples of the aforementioned polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, and the like. The addition amount of these initiators is preferably 0.01 to 25 mol% relative to the total of the monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the perspective of production efficiency.

[0581] The aforementioned polymerization initiator can be added to the reaction kettle after the aforementioned monomer solution, or an initiator solution can be prepared separately from the aforementioned monomer solution, and each can be independently supplied to the reaction kettle. During the standby time, the polymerization reaction may proceed due to the free radicals generated from the initiator and generate ultra-high molecular weight substances. Therefore, from the perspective of quality control, it is preferably to prepare and drop the monomer solution and the initiator solution independently. The acid-labile group can be directly introduced into the monomer or can be protected or partially protected after polymerization. Also, in order to adjust the molecular weight, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can be used in combination. In this case, the addition amount of these chain transfer agents is preferably 0.01 to 20 mol% relative to the total of the monomers to be polymerized.

[0582] When it is a monomer containing a hydroxyl group, during polymerization, the hydroxyl group can be pre-substituted with an acetal group such as ethoxyethoxy that is easily deprotected by an acid, and deprotected with a weak acid and water after polymerization, or can be pre-substituted with an acetyl group, a formyl group, a trimethylacetyl group, etc., and subjected to base hydrolysis after polymerization.

[0583] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers can be added with a radical polymerization initiator and heated for polymerization in an organic solvent, or acetoxystyrene or acetoxyvinylnaphthalene can be used, and after polymerization, the acetoxy group can be deprotected to polyhydroxystyrene or hydroxyvinylnaphthalene by base hydrolysis.

[0584] Specific examples of the base during base hydrolysis include ammonia water, triethylamine, etc. Also, 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.

[0585] Also, the amount of each monomer in the aforementioned monomer solution can be appropriately set to, for example, an ideal content ratio of the aforementioned repeating unit.

[0586] For the polymer obtained by the aforementioned production method, the reaction solution obtained from the polymerization reaction may be used as the final product, or the polymerization solution may be added to a poor solvent, and the obtained powder may be treated as the final product through purification steps such as the reprecipitation method for obtaining the powder. However, from the viewpoints of operation efficiency and quality stabilization, it is better to treat the polymer solution obtained by dissolving the powder obtained from the purification step in a solvent as the final product.

[0587] Specific examples of the solvent used at this time include ketones such as cyclohexanone and methyl-2-n-amyl ketone described in paragraphs

[0144] to

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

[0588] In the aforementioned polymer solution, the concentration of the polymer is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0589] It is preferable to filter the aforementioned reaction solution and polymer solution through a filter. By performing filter filtration, foreign matters and gels that may cause defects can be removed, which is effective for quality stabilization.

[0590] Examples of the material of the filter used for the aforementioned filter filtration include materials such as fluorocarbon-based, cellulose-based, nylon-based, polyester-based, and hydrocarbon-based, but in the filtration step of the chemically amplified resist composition, it is better to use a filter formed of a fluorocarbon-based material called so-called Teflon (registered trademark), a hydrocarbon-based material such as polyethylene or polypropylene, or nylon. The pore size of the filter can be appropriately selected according to the target cleanliness, but it is preferably 100 nm or less, more preferably 20 nm or less. Also, these filters can be used alone or in combination of multiple filters. The filtration method may only pass the solution once, but it is better to circulate the solution and perform multiple filtrations. The filtration step can be carried out in any order and number in the polymer production step, but it is preferable to filter the reaction solution, polymer solution, or both after the polymerization reaction.

[0591] [Chemically Amplified Resist Composition]

[0592] [(A) Base Polymer]

[0593] The chemically amplified resist composition of the present invention contains a base polymer containing the aforementioned polymer as component (A).

[0594] The aforementioned polymer may be used alone or in combination of two or more having different composition ratios, Mw and / or Mw / Mn. Further, the (A) base polymer may contain, in addition to the aforementioned polymer, a hydride of a ring-opening metathesis polymer, and in this regard, those described in Japanese Patent Application Laid-Open No. 2003-66612 can be used.

[0595] [(B) Quencher]

[0596] The chemically amplified resist composition of the present invention may also contain a quencher as component (B). Further, in the present invention, the quencher is a material for preventing the diffusion of acid to the unexposed portion by capturing the acid generated by the photoacid generator in the chemically amplified resist composition and forming a desired pattern.

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

[0598] [Chemical formula 213]

[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, excluding the state where the hydrogen atom bonded to the α-position carbon atom of the sulfo group is a fluorine atom or a fluoroalkyl group. In formula (2), R q2 is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom.

[0601] R q1 The hydrocarbon group having 1 to 40 carbon atoms represented, specifically, for example, alkyl groups having 1 to 40 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl; cycloalkyl groups having 3 to 40 carbon atoms such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo [5.2.1.0 2,6 decyl, adamantyl; aryl groups having 6 to 40 carbon atoms such as phenyl, naphthyl, anthryl, etc. Further, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and the -CH 2A part of "-" may also be substituted by a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. As a result, it may also contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0602] R q2 The hydrocarbon group represented by, specifically, in addition to the substituents exemplified for R q1 Specific examples thereof may also include fluorinated saturated hydrocarbon groups such as trifluoromethyl and trifluoroethyl, and fluorinated aryl groups such as pentafluorophenyl and 4-trifluoromethylphenyl.

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

[0604] [Chemical formula 214]

[0605]

[0606] [Chemical formula 215]

[0607]

[0608] [Chemical formula 216]

[0609]

[0610] Specific examples of the anion of the onium salt represented by formula (2) are listed below, but are not limited to these.

[0611] [Chemical formula 217]

[0612]

[0613] [Chemical formula 218]

[0614]

[0615] [Chemical formula 219]

[0616]

[0617] In formulas (1) and (2), Mq + is an onium cation. The onium cation is preferably a sulfonium cation represented by the aforementioned formula (cation-1), an iodonium cation represented by the aforementioned formula (cation-2), or an ammonium cation represented by the following formula (cation-3).

[0618] [Chemical formula 220]

[0619]

[0620] In formula (cation-3), R ct6 ~R ct9 are each independently a hydrocarbon group having 1 to 40 carbon atoms which may also contain a heteroatom. Further, R ct6 and R ct7 may also be bonded to each other and together with the nitrogen atom to which they are bonded form a ring. Specific examples of the aforementioned hydrocarbon group are the same as the examples exemplified for R ct1 ~R ct5 in the descriptions of formulas (cation-1) and (cation-2).

[0621] Specific examples of the ammonium cation represented by formula (cation-3) are listed below, but are not limited to these.

[0622] [Chemical formula 221]

[0623]

[0624] Specific examples of the onium salt represented by formula (1) or (2) are any combination of the aforementioned anions and cations. Further, these onium salts can be easily prepared by an ion exchange reaction using known organic chemical methods. For the ion exchange reaction, reference can be made to, for example, Japanese Unexamined Patent Application Publication No. 2007-145797.

[0625] The onium salt represented by formula (1) or (2) acts as a quencher in the chemically amplified resist composition of the present invention. The reason is that each counter anion of the aforementioned onium salt is a conjugate base of a weak acid. Here, the so-called weak acid refers to an acid having an acidity that does not deprotect the acid-labile group of the unit that cannot make the base polymer contain the acid-labile group. The onium salt represented by formula (1) or (2) acts as a quencher when used in combination with an onium salt type photoacid generator having a conjugate base of a strong acid such as α-position fluorinated sulfonic acid as a counter anion. That is, when an onium salt that generates a strong acid such as α-position fluorinated sulfonic acid and an onium salt that generates a weak acid such as non-fluorinated sulfonic acid or carboxylic acid are mixed and used, if the strong acid generated from the photoacid generator due to high-energy ray irradiation collides with the onium salt having an unreacted weak acid anion, a weak acid is released due to salt exchange, and an onium salt having a strong acid anion is generated. In this process, the strong acid is exchanged for a weak acid with lower catalytic ability, so the acid is deactivated macroscopically and the acid diffusion can be controlled.

[0626] Further, as the quencher (B), an onium salt having a sulfonium cation and a phenoxide anion moiety in the same molecule described in Japanese Patent No. 6848776 can also be used, and an onium salt having a sulfonium cation and a carboxylate anion moiety in the same molecule described in Japanese Patent No. 6583136, Japanese Unexamined Patent Application Publication No. 2020-200311, and an onium salt having an iodonium cation and a carboxylate anion moiety in the same molecule described in Japanese Patent No. 6274755.

[0627] Here, when the photoacid generator that generates a strong acid is an onium salt, as described above, the strong acid generated by high-energy ray irradiation can be exchanged for a weak acid. On the other hand, it is considered that salt exchange due to the collision between the weak acid generated by high-energy ray irradiation and the unreacted onium salt that generates a strong acid is not likely to occur. The reason is caused by the phenomenon that the onium cation is relatively easy to form an ion pair with the anion of the strong acid.

[0628] In the chemically amplified resist composition of the present invention, when an onium salt represented by the formula (1) or (2) is contained as the (B) quencher, its content is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, relative to 80 parts by mass of the (A) base polymer. If the onium salt type quencher of the (B) component is within the above range, the resolution is good and the sensitivity will not decrease significantly, so it is ideal. The onium salt represented by the formula (1) or (2) can be used alone or in combination of two or more.

[0629] The chemically amplified resist composition of the present invention may also contain a nitrogen-containing compound as the (B) quencher. Specific examples of the nitrogen-containing compound of the (B) component include primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Laid-Open No. 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. Further, compounds described in Japanese Patent No. 3790649, which are compounds obtained by protecting a primary or secondary amine with a carbamate group, can be cited. Furthermore, compounds having an acid-labile group in the molecule, as described in Japanese Patent Application Laid-Open No. 2009-109595, can be cited.

[0630] Also, a sulfonium salt having a nitrogen-containing substituent can be used as the nitrogen-containing compound. Such a compound acts as a quencher in the unexposed portion and loses its quencher ability due to neutralization with the acid generated by itself in the exposed portion, acting as a so-called photo-decomposable base. By using a photo-decomposable base, the contrast between the exposed portion and the unexposed portion can be further enhanced. For photo-decomposable bases, reference can be made to Japanese Patent Application Laid-Open No. 2009-109595, Japanese Patent Application Laid-Open No. 2012-46501, etc.

[0631] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as the (B) quencher, its content is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass, relative to 80 parts by mass of the (A) base polymer. The aforementioned nitrogen-containing compounds can be used alone or in combination of two or more.

[0632] [(C) Organic solvent]

[0633] The chemically amplified resist composition of the present invention may also contain an organic solvent as the component (C). The organic solvent (C) is not particularly limited as long as it can dissolve the aforementioned components and the components described below. Specific examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-amyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ketoalcohols such as DAA; ethers such as PGME, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monoterbutyl ether acetate; lactones such as GBL; and mixed solvents thereof.

[0634] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixed solvents thereof, which have particularly excellent solubility for the base polymer of the component (A), are preferred.

[0635] In the chemically amplified resist composition of the present invention, the content of the organic solvent (C) 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 (C) may be used alone or in combination of two or more.

[0636] [(D) Acid generator]

[0637] The chemically amplified resist composition of the present invention may also contain an acid generator within the range that does not impair the effects of the present invention. The aforementioned acid generator is, for example, a compound that generates an acid upon exposure to actinic light or radiation (photoacid generator). The photoacid generator is not particularly limited as long as it is a compound that generates an acid upon irradiation with high-energy rays, and those that generate sulfonic acid, imidic acid, or methylated acid are preferred. Preferred photoacid generators include sulfonium salts, iodonium salts, sulfonyl diazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate type acid generators. Specific examples of the acid generator are those described in paragraphs

[0122] to

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

[0638] Furthermore, sulfonium salts represented by the following formula (3-1) and iodonium salts represented by the following formula (3-2) can also be preferably used as the photoacid generator.

[0639] [Chemical formula 222]

[0640]

[0641] In the formulas (3-1) and (3-2), R 101 ~R 105Each independently represents a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. Specific examples of the foregoing halogen atom and hydrocarbon group are the same as those exemplified for the halogen atom and hydrocarbon group represented by R in the description of Formula (cation-1) and (cation-2). Further, a part or all of the hydrogen atoms of the foregoing hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of -CH- of the foregoing hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Further, R and R may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. Specific examples of the ring formed at this time are the same as those exemplified for the ring that can be formed together with the sulfur atom to which R and R are bonded to each other in the description of Formula (cation-1). ct1 ~R ct5 The halogen atom and hydrocarbon group represented are the same examples. Also, a part or all of the hydrogen atoms of the foregoing hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of -CH- of the foregoing hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Also, R and R may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. Specific examples of the ring formed at this time are the same as those exemplified for the ring that can be formed together with the sulfur atom to which R and R are bonded to each other in the description of Formula (cation-1). 2 - may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Also, R and R may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. Specific examples of the ring formed at this time are the same as those exemplified for the ring that can be formed together with the sulfur atom to which R and R are bonded to each other in the description of Formula (cation-1). 101 and R 102 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. Specific examples of the ring formed at this time are the same as those exemplified for the ring that can be formed together with the sulfur atom to which R and R are bonded to each other in the description of Formula (cation-1). ct1 and R ct2 bonded to each other and the ring that can be formed together with the sulfur atom to which they are bonded are the same examples.

[0642] Specific examples of the cation of the sulfonium salt represented by Formula (3-1) are the same as those exemplified for the sulfonium cation represented by Formula (cation-1). Also, specific examples of the cation of the oxosulfonium salt represented by Formula (4-2) are the same as those exemplified for the oxosulfonium cation represented by Formula (cation-2).

[0643] In Formulas (3-1) and (3-2), Xa - is an anion selected from the following Formulas (3A) to (3D).

[0644] [Chemical formula 223]

[0645]

[0646] In Formula (3A), R fa is a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may also contain a heteroatom. The foregoing hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof are the same as those exemplified for R in the description of the following Formula (3A') below. fa1 The anion represented by Formula (3A) is preferably the one represented by the following Formula (3A').

[0647] The anion represented by Formula (3A) is preferably the one represented by the following Formula (3A').

[0648] [Chemical formula 224]

[0649]

[0650] In formula (3A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0651] In formula (3A'), R fa1 is a hydrocarbon group having 1 to 38 carbon atoms which may also contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and more preferably an oxygen atom. From the viewpoint of obtaining high resolution in fine pattern formation, the hydrocarbon group having 6 to 30 carbon atoms is particularly preferred.

[0652] R fa1 The hydrocarbon group having 1 to 38 carbon atoms represented may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, icosyl, etc.; cycloaliphatic saturated hydrocarbon groups having 3 to 38 carbon atoms such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, dicyclohexylmethyl, etc.; unsaturated aliphatic hydrocarbon groups having 2 to 38 carbon atoms such as allyl, 3-cyclohexenyl, etc.; aryl groups having 6 to 38 carbon atoms such as phenyl, 1-naphthyl, 2-naphthyl, etc.; aralkyl groups having 7 to 38 carbon atoms such as benzyl, diphenylmethyl, etc.; groups obtained by combining them, etc.

[0653] Furthermore, part or all of the hydrogen atoms of the hydrocarbon group may also be replaced by a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and part of the -CH 2 - of the hydrocarbon group may also be replaced by a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. As a result, it may also contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Furthermore, the heteroatom is preferably an oxygen atom. Specific examples of the hydrocarbon group containing a heteroatom include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, 3-oxocyclohexyl, etc.

[0654] For the synthesis of sulfonium salts containing anions represented by formula (3A'), refer to Japanese Patent Laid-Open Nos. 2007-145797, 2008-106045, 2009-7327, 2009-258695, etc. Also, sulfonium salts described in Japanese Patent Laid-Open Nos. 2010-215608, 2012-41320, 2012-106986, 2012-153644, etc. are also preferably used.

[0655] Specific examples of the anion represented by formula (3A) are listed below, but are not limited to these. Also, in the following formula, Ac is an acetyl group.

[0656] [Chemical formula 225]

[0657]

[0658] [Chemical formula 226]

[0659]

[0660] [Chemical formula 227]

[0661]

[0662] [Chemical formula 228]

[0663]

[0664] In formula (3B), R fb1 and R fb2 are each independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof are the same as those exemplified for the hydrocarbon group represented by R fa1 in formula (3A'). R fb1 and R fb2 are preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Also, R fb1 and R fb2 may also be bonded to each other and together with the group to which they are bonded (-CF 2 -SO 2 -N - -SO 2 -CF 2 -) form a ring. In this case, the group obtained by bonding R fb1 and R fb2 to each other is preferably a fluoroethylene or fluoropropylene group.

[0665] In formula (3C), R fc1 , Rfc2 and R fc3 are each independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof are the same as the examples of the hydrocarbon group represented by R fa1 in formula (3A'). R fc1 , R fc2 and R fc3 are preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Further, R fc1 and R fc2 may also be bonded to each other and together with the group to which they are bonded (-CF 2 -SO 2 -C - -SO 2 -CF 2 -) form a ring. In this case, the group obtained by bonding R fc1 and R fc2 to each other is preferably a fluoroethylene or fluoropropylene group.

[0666] In formula (3D), R fd is a hydrocarbon group having 1 to 40 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof are the same as the examples of the hydrocarbon group represented by R fa1 in formula (3A').

[0667] For the synthesis of the sulfonium salt containing the anion represented by formula (3D), see Japanese Patent Laid-Open No. 2010-215608 and Japanese Patent Laid-Open No. 2014-133723.

[0668] Specific examples of the anion represented by formula (3D) are listed below, but are not limited to these.

[0669] [Chemical formula 229]

[0670]

[0671] [Chemical formula 230]

[0672]

[0673] Further, the photoacid generator containing the anion represented by formula (3D) has no fluorine atom at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position, and thus has sufficient acidity to cleave the acid-labile group in the base polymer. Therefore, it can be used as a photoacid generator.

[0674] It is also desirable that the photoacid generator is represented by the following formula (4).

[0675] [Chemical formula 231]

[0676]

[0677] In formula (4), R 201 and R 202 are each independently a hydrocarbon group having 1 to 30 carbon atoms which may also contain a heteroatom. R 203 is an alkylene group having 1 to 30 carbon atoms which may also contain a heteroatom. Further, any two of R 201 , R 202 and R 203 may also be bonded to each other and together with the sulfur atom to which they are bonded form a ring. Specific examples of the ring at this time are the same as the examples of the ring that can be formed together with the sulfur atom to which they are bonded when R ct1 and R ct2 are bonded to each other as exemplified in the description of formula (cation-1).

[0678] 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 are alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl; cycloalkyl groups having 3 to 30 carbon atoms such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6 decyl, adamantyl; aryl groups having 6 to 30 carbon atoms such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl, anthryl; groups obtained by combining them, etc. Further, some or all of the hydrogen atoms of the hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and a part of -CH 2 - of the hydrocarbon group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, and as a result, it may also contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0679] R 203The C1-C30 alkylene group represented may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkylene groups having 1 to 30 carbon atoms such as methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, heptadecane-1,17-diyl; cycloaliphatic saturated alkylene groups having 3 to 30 carbon atoms such as cyclopentanediyl, cyclohexanediyl, norbornanediyl, adamantanediyl; arylene groups having 6 to 30 carbon atoms such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, tert-butylnaphthylene; groups obtained by combining them, etc. Further, part or all of the hydrogen atoms of the aforementioned alkylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and part of -CH 2 - of the aforementioned alkylene group may also be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. The aforementioned heteroatom is preferably an oxygen atom.

[0680] In formula (4), L A is a single bond, an ether bond, or an alkylene group having 1 to 20 carbon atoms which may also contain a heteroatom. The aforementioned alkylene group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof are the same as the examples exemplified for the alkylene group represented by R 203 .

[0681] In formula (4), X A , X B , X C and X D are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group. However, at least one of X A , X B , X C and X D is a fluorine atom or a trifluoromethyl group.

[0682] In formula (4), k is an integer from 0 to 3.

[0683] The photoacid generator represented by formula (4) is preferably the one represented by the following formula (4').

[0684] [Chemical formula 232]

[0685]

[0686] In formula (4'), L A is as described above. R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 301 , R 302 and R 303 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof are the same as the examples exemplified for the hydrocarbon group represented by R fa1 in formula (3A'). x and y are each independently an integer from 0 to 5. z is an integer from 0 to 4.

[0687] Specific examples of the photoacid generator represented by formula (4) are the same as the examples exemplified for the photoacid generator represented by formula (2) in Japanese Patent Application Laid-Open No. 2017-26980.

[0688] Among the aforementioned photoacid generators, those containing an anion represented by formula (3A') or (3D) have small acid diffusion and excellent solubility in solvents, and are particularly desirable. Also, those represented by formula (4') have extremely small acid diffusion and are particularly desirable.

[0689] Also, for 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 (5-2) can also be used.

[0690] [Chemical formula 233]

[0691]

[0692] 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. It is more desirable that q is 1, 2 or 3, and even more desirable that q is 2 or 3. It is preferable that r is 0, 1 or 2.

[0693] In formulas (5-1) and (5-2), L 1 is a single bond, an ether bond or an ester bond, or a saturated alkylene group having 1 to 6 carbon atoms which may also contain an ether bond or an ester bond. The aforementioned saturated alkylene group may be linear, branched or cyclic.

[0694] In formulas (5-1) and (5-2), L 2When 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. This linking group may also contain an oxygen atom, a sulfur atom or a nitrogen atom.

[0695] In formulas (5-1) and (5-2), R 401 is a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon oxy group having 1 to 20 carbon atoms, a hydrocarbon carbonyl group having 2 to 20 carbon atoms, a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms or a hydrocarbon sulfonyloxy group having 1 to 20 carbon atoms, which may also contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group or an ether bond, or -N(R 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-O-R 401D . R 401A and R 401B are each independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. R 401C is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, which may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. R 401D is an aliphatic hydrocarbon group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms or an aralkyl group having 7 to 15 carbon atoms, which may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. The aforementioned hydrocarbon group, hydrocarbon oxy group, hydrocarbon carbonyl group, hydrocarbon oxycarbonyl group, hydrocarbon carbonyloxy group and hydrocarbon sulfonyloxy group may be linear, branched or cyclic. When p and / or r is 2 or more, each R 401 may be the same or different from each other.

[0696] Among these, R 401 is preferably a hydroxyl group, -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-O-R 401D , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group or the like.

[0697] In formulas (5-1) and (5-2), Rf 1 to Rf 4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of these is a fluorine atom or a trifluoromethyl group. Also, it is possible that Rf 1 and Rf 2Combine to form a carbonyl group. In particular, Rf 3 and Rf 4 are preferably both fluorine atoms.

[0698] In formulas (5-1) and (5-2), R 402 ~R 406 are each independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated, unsaturated, linear, branched, or cyclic. Specific examples thereof are the same as the hydrocarbon groups exemplified for R ct1 ~R ct5 in the descriptions of formulas (cation-1) and (cation-2). Also, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted with a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone ring, a sulfo group, or a group containing a sulfonium salt, and part of -CH 2 - of the aforementioned hydrocarbon group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate bond. Also, R 402 and R 403 may also be bonded to each other and together with the sulfur atom to which they are bonded form a ring. In this case, specific examples of the aforementioned ring are the same as the rings exemplified for R ct1 and R ct2 which can be bonded to each other and together with the sulfur atom to which they are bonded to form a ring.

[0699] Specific examples of the cation of the sulfonium salt represented by formula (5-1) are the same as the sulfonium cations exemplified for formula (cation-1). Also, specific examples of the cation of the oxonium salt represented by formula (5-2) are the same as the oxonium cations exemplified for formula (cation-2).

[0700] Specific examples of the anion of the onium salt represented by formula (5-1) or (5-2) are listed below, but are not limited to these.

[0701] [Chemical formula 234]

[0702]

[0703] [Chemical formula 235]

[0704]

[0705] [Chemical formula 236]

[0706]

[0707] [Chemical formula 237]

[0708]

[0709] [Chemical formula 238]

[0710]

[0711] [Chemical formula 239]

[0712]

[0713] [Chemical formula 240]

[0714]

[0715] [Chemical formula 241]

[0716]

[0717] [Chemical formula 242]

[0718]

[0719] [Chemical formula 243]

[0720]

[0721] [Chemical formula 244]

[0722]

[0723] [Chemical formula 245]

[0724]

[0725] [Chemical formula 246]

[0726]

[0727] [Chemical formula 247]

[0728]

[0729] [Chemical formula 248]

[0730]

[0731] [Chemical formula 249]

[0732]

[0733] [Chemical formula 250]

[0734]

[0735] [Chemical formula 251]

[0736]

[0737] [Chemical formula 252]

[0738]

[0739] [Chemical formula 253]

[0740]

[0741] [Chemical formula 254]

[0742]

[0743] [Chemical formula 255]

[0744]

[0745] When the chemically amplified resist composition of the present invention contains a (D) acid generator, its content is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 20 parts by mass, relative to 80 parts by mass of the (A) base polymer. If the addition amount of the acid generator of the (D) component is within the above range, the resolution is good, and there is no problem of foreign matter generation when the resist film is developed or peeled off, so it is ideal. The (D) acid generator can be used alone or in combination of two or more.

[0746] [(E) surfactant]

[0747] The chemically amplified resist composition of the present invention may further contain a surfactant as the (E) component. The (E) surfactant is preferably a surfactant that is insoluble or hardly soluble in water and soluble in an alkaline developer, or a surfactant that is insoluble or hardly soluble in both water and an alkaline developer. Such surfactants can be referred to those described in Japanese Patent Application Laid-Open No. 2010-215608 and Japanese Patent Application Laid-Open No. 2011-16746.

[0748] Among the surfactants that are insoluble or hardly soluble in both water and an alkaline developer, FC-4430 (manufactured by 3M Company), surflon (registered trademark) S-381 (manufactured by AGC Seimichemical Co., Ltd.), OLFINE (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimichemical Co., Ltd.), and oxetane ring-opening polymers represented by the following formula (surf-1) are preferable.

[0749] [Chemical formula 256]

[0750]

[0751] Here, R, Rf, A, B, C, m, and n are not limited to the foregoing description and are only applicable to formula (surf-1). R is an aliphatic group with a valence of 2 to 4 and a carbon number of 2 to 5. For the foregoing aliphatic group, examples of the divalent group include ethylene, 1,4-butylene, 1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,5-pentylene, etc., and examples of the trivalent or tetravalent group are as follows.

[0752] [Chemical formula 257]

[0753]

[0754] In the formula, the dashed lines are atomic bonds, each being a partial structure derived from glycerol, trimethylolethane, trimethylolpropane, or pentaerythritol.

[0755] Among these, 1,4-butylene, 2,2-dimethyl-1,3-propylene, etc. are preferred.

[0756] Rf is trifluoromethyl or pentafluoroethyl, preferably trifluoromethyl. m is an integer from 0 to 3, n is an integer from 1 to 4, and the sum of n and m is the valence of R, which is an integer from 2 to 4. A is 1. B is an integer from 2 to 25, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. Also, the arrangement of each constituent unit in formula (surf-1) is not specified and can be block-bonded or randomly bonded. For the manufacture of the surfactant of the partially fluorinated oxetane ring-opening polymer system, refer to the specification of U.S. Patent No. 5650483, etc.

[0757] For a surfactant that is insoluble or hardly soluble in water and soluble in an alkali developer, when an ArF immersion lithography does not use a resist protective film, it has the effect of reducing water infiltration and leaching by aligning on the surface of the resist film. Therefore, it inhibits the dissolution of water-soluble components from the resist film and reduces damage to the exposure device, so it is useful. Also, it becomes soluble during alkali aqueous solution development after exposure or post-exposure bake (PEB) and is not easily turned into foreign substances that cause defects, so it is useful. Such a surfactant has the property of being insoluble or hardly soluble in water and soluble in an alkali developer and is a polymer-type surfactant, also known as a hydrophobic resin, and is preferably one with high water repellency and improved water lubricity.

[0758] Specific examples of such a polymer-type surfactant include those containing at least one repeating unit selected from the repeating units represented by the following formulae (6A) to (6E).

[0759] [Chemical formula 258]

[0760]

[0761] In formulae (6A) to (6E), R B is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. W1 is -CH 2 -, -CH 2 CH 2 -, -O-, or two -H's separated from each other. R s1 Each independently is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R s2 is a single bond or a linear or branched alkylene group having 1 to 5 carbon atoms. R s3 Each independently is a hydrogen atom, a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group. R s3 When it is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between carbon-carbon bonds. R s4 is a (u + 1)-valent hydrocarbon group or a fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer from 1 to 3. R s5 Each independently is a hydrogen atom or a group represented by -C(=O)-O-R sa . R sa is a fluorinated hydrocarbon group having 1 to 20 carbon atoms. R s6 is a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 15 carbon atoms, and an ether bond or a carbonyl group may be inserted between its carbon-carbon bonds.

[0762] R s1 It is preferable that the hydrocarbon group having 1 to 10 carbon atoms represented by R is a saturated hydrocarbon group, and any of linear, branched, and cyclic forms is acceptable. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cycloaliphatic saturated hydrocarbon groups having 3 to 10 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl. Among these, those having 1 to 6 carbon atoms are preferred.

[0763] R s2 It is preferable that the alkylene group represented by R is a saturated alkylene group, and any of linear, branched, and cyclic forms is acceptable. Specific examples thereof include methylene, ethylene, propylene, butylene, and pentylene.

[0764] 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 saturated hydrocarbon groups, aliphatic unsaturated hydrocarbon groups such as alkenyl and alkynyl groups, etc., and saturated hydrocarbon groups are preferred. Specific examples of the aforementioned saturated hydrocarbon groups are as exemplified for the hydrocarbon group represented by R s1 , and in addition, for example, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, etc. R s3 or R s6 Specific examples of the fluorinated hydrocarbon group represented by include groups in which a part or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon group are replaced by fluorine atoms. As described above, an ether bond or a carbonyl group may also be inserted between these carbon-carbon bonds.

[0765] R s3 Specific examples of the acid-labile group represented, for example, by the groups represented by the aforementioned formulas (AL-3) to (AL-5), a trialkylsilyl group in which each alkyl group has 1 to 6 carbon atoms, an alkyl group having an oxo group with 4 to 20 carbon atoms, and the like.

[0766] R s4 The (u + 1)-valent hydrocarbon group or fluorinated hydrocarbon group represented may be linear, branched, or cyclic, and specific examples thereof include groups obtained by removing u more hydrogen atoms from the aforementioned hydrocarbon group or fluorinated hydrocarbon group.

[0767] R sa The fluorinated hydrocarbon group represented is preferably saturated and may be any of linear, branched, or cyclic. Specific examples thereof include those in which part or all of the hydrogen atoms of the aforementioned hydrocarbon group 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, 2-(perfluorodecyl)ethyl, and the like.

[0768] Specific examples of the repeating unit represented by any one of formulas (6A) to (6E) are listed below, but are not limited thereto. Also, in the following formula, R B As described above.

[0769] [Chemical formula 259]

[0770]

[0771] [Chemical formula 260]

[0772]

[0773] [Chemical formula 261]

[0774]

[0775] [Chemical formula 262]

[0776]

[0777] [Chemical formula 263]

[0778]

[0779] The aforementioned polymeric surfactant may further contain other repeating units in addition to the repeating units represented by the formulas (6A) to (6E). Specific examples of the other repeating units include repeating units obtained from methacrylic acid, α-trifluoromethyl methacrylic acid derivatives, and the like. In the polymeric surfactant, the content of the repeating units represented by the formulas (6A) to (6E) is preferably 20 mol% or more, more preferably 60 mol% or more, and most preferably 100 mol% of all the repeating units.

[0780] The Mw of the aforementioned polymeric surfactant is preferably from 1,000 to 500,000, more preferably from 3,000 to 100,000. The Mw / Mn is preferably from 1.0 to 2.0, more preferably from 1.0 to 1.6.

[0781] A method for synthesizing the aforementioned polymeric surfactant, for example, a method of polymerizing repeating units represented by the formulas (6A) to (6E) and, if necessary, an unsaturated bond-containing monomer that gives other repeating units in an organic solvent by adding a radical initiator and heating. Specific examples of the organic solvent used in the polymerization include toluene, benzene, THF, diethyl ether, dioxane, and the like. Specific examples of the polymerization initiator include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, and the like. The reaction temperature is preferably 50 to 100 °C. The reaction time is preferably 4 to 24 hours. The acid-labile group can be directly used and introduced into the monomer, or it can be protected or partially protected after polymerization.

[0782] When synthesizing the aforementioned polymeric surfactant, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol can also be used to adjust the molecular weight. At this time, the addition amount of these chain transfer agents is preferably 0.01 to 10 mol% relative to the total molar amount of the monomers to be polymerized.

[0783] When the chemically amplified resist composition of the present invention contains (E) a surfactant, its content is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of (A) the base polymer. If the content of (E) the surfactant is 0.1 part by mass or more, the receding contact angle between the resist film surface and water will be sufficiently increased. If it is 50 parts by mass or less, the dissolution rate of the resist film surface with respect to the developer is small, and the height of the formed fine pattern can be sufficiently maintained. (E) The surfactant can be used alone or in combination of two or more.

[0784] [(F) Dissolution inhibitor]

[0785] The chemically amplified resist composition of the present invention may further contain a dissolution inhibitor as the component (F). When the chemically amplified resist composition of the present invention is a positive type, by blending a dissolution inhibitor, the difference in dissolution rate between the exposed portion and the unexposed portion can be further increased, and the resolution can be further improved.

[0786] Specific examples of the aforementioned dissolution inhibitor include, for example, a compound having a molecular weight preferably of 100 to 1000, more preferably of 150 to 800 and containing two or more phenolic hydroxyl groups in the molecule, and a hydrogen atom of the phenolic hydroxyl group is replaced by an acid-labile group in a proportion of 0 to 100 mol% as a whole, or a compound having a carboxyl group in the molecule and a hydrogen atom of the carboxyl group is replaced by an acid-labile group in an average proportion of 50 to 100 mol% as a whole. Specifically, for example, bisphenol A, triphenol, phenolphthalein, cresol novolak, naphthalene carboxylic acid, adamantane carboxylic acid, a compound in which a hydrogen atom of a hydroxyl group or a carboxyl group of cholic acid is replaced by an acid-labile group, etc., for example, those described in paragraphs

[0155] to

[0178] of Japanese Patent Laid-Open No. 2008-122932.

[0787] When the chemically amplified resist composition of the present invention contains the dissolution inhibitor (F), 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 component (A) base polymer. The dissolution inhibitor (F) may be used alone or in combination of two or more.

[0788] [(G) Other components]

[0789] The chemically amplified resist composition of the present invention may also contain a compound that decomposes by an acid and generates an acid (acid-proliferating compound), an organic acid derivative, a fluorine-substituted alcohol, a water repellency improver, etc. as the component (G) other components. The aforementioned acid-proliferating compound may refer to the compounds described in Japanese Patent Laid-Open No. 2009-269953 or Japanese Patent Laid-Open No. 2010-215608. When the aforementioned acid-proliferating 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 component (A) base polymer. If the content is too large, it is difficult to control acid diffusion, and sometimes resolution deterioration and pattern shape deterioration may occur. The aforementioned organic acid derivative and fluorine-substituted alcohol may refer to the compounds described in Japanese Patent Laid-Open No. 2009-269953 or Japanese Patent Laid-Open No. 2010-215608.

[0790] The above-mentioned water repellency improver can be used in immersion lithography without a top coat. The above-mentioned water repellency improver is preferably a polymer containing a fluorinated alkyl group, a polymer containing 1,1,1,3,3,3-hexafluoro-2-propanol residues with a specific structure, etc., and those exemplified in Japanese Patent Application Laid-Open No. 2007-297590, Japanese Patent Application Laid-Open No. 2008-111103, etc. are more preferable. The above-mentioned water repellency improver needs to be dissolved in an alkali developer or an organic solvent developer. The above-mentioned specific water repellency improver having 1,1,1,3,3,3-hexafluoro-2-propanol residues has good solubility in the developer. Regarding the water repellency improver, a polymer containing repeating units of amino group and amine salt has a high effect of preventing the evaporation of acid in PEB and preventing the opening defect of the hole pattern after development. When the chemically amplified resist composition of the present invention contains the above-mentioned water repellency improver, its content is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, based on 80 parts by mass of the (A) base polymer.

[0791] [Pattern formation method]

[0792] When the chemically amplified resist composition of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be adopted. For example, a pattern formation method, such as a method including the following steps: forming a resist film on a substrate using the above-mentioned chemically amplified resist composition, exposing the above-mentioned resist film with high-energy rays, and developing the above-mentioned exposed resist film using a developer.

[0793] First, the chemically amplified resist composition of the present invention is applied onto a substrate for integrated circuit manufacture (Si, SiO 2 , SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, etc.) or a substrate for mask circuit manufacture (Cr, CrO, CrON, MoSi 2 , SiO 2 , etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, knife coating, etc., so that the coating film thickness becomes 0.01 to 2.0 μm. It is 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.

[0794] Secondly, the above-mentioned resist film is exposed using high-energy rays. The above-mentioned high-energy rays, for example, ultraviolet rays, far ultraviolet rays, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer lasers, γ-rays, synchrotron radiation, etc. When using the above-mentioned ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, γ-rays, synchrotron radiation, etc. as the high-energy rays, it is directly or using a mask for forming a target pattern, and the exposure dose is preferably about 1 to 200 mJ / cm 2, more preferably about 10 to 100 mJ / cm 2 Irradiation. When the high-energy ray used is EB, it is directly irradiated or irradiated through a mask for forming a target pattern, and the exposure dose is preferably about 0.1 to 100 μC / cm 2 , more preferably about 0.5 to 50 μC / cm 2 . The chemically amplified resist composition of the present invention is particularly suitable for fine patterning using an ArF excimer laser having a wavelength of 193 nm, a KrF excimer laser having a wavelength of 248 nm, EB, EUV having a wavelength of 3 to 15 nm, X-rays, soft X-rays, γ-rays or synchrotron radiation among high-energy rays.

[0795] After exposure, PEB can be carried out 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.

[0796] After exposure or after PEB, a developer containing an aqueous alkali solution such as 0.1 to 10% by mass, preferably 2 to 5% by mass of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. is used, and development is carried out by a conventional method such as dip method, puddle method, spray method, etc. at 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes. The irradiated part is dissolved in the developer, and the unexposed part is not dissolved, and a positive pattern of the target can be formed on the substrate.

[0797] An organic solvent developer may also be used instead of the aqueous alkali solution to obtain a negative pattern. Specific examples of the developer used at this time are, for example, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenyl ethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents can be used alone or in combination of two or more.

[0798] Rinsing may also be performed at the end of development. It is preferable that the rinsing liquid be a solvent that is miscible with the developer and does not dissolve the resist film. As such a solvent, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms are ideal.

[0799] Specific examples of the alcohols having 3 to 10 carbon atoms include n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentanol, neopentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, and the like.

[0800] Specific examples of the ether compounds having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, di-n-hexyl ether, and the like.

[0801] 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, cyclononane, and the like. Specific examples of the alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, and the like. Specific examples of the alkynes having 6 to 12 carbon atoms include hexyne, heptyne, octyne, and the like.

[0802] Specific examples of the aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, and the like.

[0803] By performing rinsing, collapse of the resist pattern and occurrence of defects can be reduced. Also, rinsing is not necessary, and by not performing rinsing, the amount of solvent used can be reduced.

[0804] The developed hole pattern and trench pattern can be shrunk using a heat flow, RELACS technique, or DSA technique. A shrinkage agent is applied to the hole pattern, and by diffusion of the acid catalyst from the resist film during baking, crosslinking of the shrinkage agent occurs on the surface of the resist film, and the shrinkage agent adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds to remove the excess shrinkage agent and shrink the hole pattern.

[0805] [Example]

[0806] The following synthesis examples, examples and comparative examples are used to specifically illustrate the present invention, but the present invention is not limited by the following examples.

[0807] [1] Synthesis of basic polymer

[0808] The monomers used for the synthesis of the basic polymer are shown below.

[0809] [Chemical formula 264]

[0810]

[0811] [Chemical formula 265]

[0812]

[0813] [Chemical formula 266]

[0814]

[0815] [Chemical formula 267]

[0816]

[0817] [Chemical formula 268]

[0818]

[0819] [Chemical formula 269]

[0820]

[0821] [Example 1-1] Synthesis of Polymer P-1

[0822] In a nitrogen atmosphere, 54.3 g of monomer a-1, 26.2 g of monomer b-1, 19.5 g of monomer c-1, 3.74 g of V-601 (manufactured by Fuji Photo Film Co., Ltd.) and 139 g of MEK were measured in a flask to prepare a monomer-polymerization initiator solution. 46 g of MEK was measured in another flask under a nitrogen atmosphere, heated to 80 °C with stirring, and the aforementioned monomer-polymerization initiator solution was added dropwise over 4 hours. After the addition was completed, the temperature of the polymerization solution was maintained at 80 °C and stirring was continued for 2 hours, and then it was cooled to room temperature. The obtained polymerization solution was added dropwise to 3000 g of vigorously stirred hexane, and the precipitated polymer was separated by filtration. The obtained polymer was washed twice with 600 g of hexane and then vacuum dried at 50 °C for 20 hours to obtain a polymer P-1 in the form of a white powder (yield 97.1 g, yield 97%). The Mw of polymer P-1 was 7500 and Mw / Mn was 1.69. Also, Mw was a polystyrene conversion measurement value obtained by GPC using DMF as a solvent.

[0823] [Chemical 270]

[0824]

[0825] [Examples 1-2 to 1-25, Comparative Examples 1-1 to 1-15] Synthesis of Polymers P-2 to P-25 and Comparative Polymers CP-1 to CP-15

[0826] The types and blending ratios of the respective monomers were changed, and the polymers shown in Tables 1 and 2 were produced in the same manner as in Example 1-1 except for this. Also, in Tables 1 and 2, the values in parentheses represent the introduction ratios (mol%) of the respective repeating units.

[0827] [Table 1]

[0828]

[0829]

[0830] [Table 2]

[0831]

[0832] [2] Preparation of Resist Composition

[0833] [Examples 2-1 to 2-25, Comparative Examples 2-1 to 2-15]

[0834] Predetermined components selected from the base polymers (P-1 to P-25) of the present invention, comparative base polymers (CP-1 to CP-15), acid generators (PAG-1, PAG-2), and quenchers (SQ-1 to SQ-3, AQ-1) were dissolved in a solvent of FC-4430 manufactured by 3M containing 0.01% by mass as a surfactant according to the compositions shown in Tables 3 and 4 below to prepare a solution, and the solution was filtered through a 0.2-μm Teflon (registered trademark) filter to prepare chemically amplified resist compositions (R-1 to R-25, CR-1 to CR-15).

[0835] [Table 3]

[0836]

[0837] [Table 4]

[0838]

[0839]

[0840] In Tables 3 and 4, the solvent, quenchers (SQ-1 to SQ-3, AQ-1), and acid generators (PAG-1, PAG-2) are as follows.

[0841] · Solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0842] DAA (diacetone alcohol)

[0843] · Quenchers: SQ-1 to SQ-3, AQ-1

[0844] [Chemical formula 271]

[0845]

[0846] · Acid generators: PAG-1, PAG-2

[0847] [Chemical formula 272]

[0848]

[0849] [3] EUV Lithography Evaluation (1)

[0850] [Examples 3-1 to 3-25, Comparative Examples 3-1 to 3-15]

[0851] Each of the chemically amplified resist compositions (R-1 to R-25, CR-1 to CR-15) shown in Tables 3 and 4 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and pre-baked at 100 °C for 60 seconds using a hot plate to form a resist film with a film thickness of 50 nm. For the aforementioned resist film, an EUV scanning exposure machine NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination) manufactured by ASML was used to change the exposure dose and focus (exposure dose pitch: 1 mJ / cm 2 2, focus pitch: 0.020 μm) while exposing an LS pattern with a line width of 18 nm and a pitch of 36 nm on the wafer. After exposure, PEB was performed at the temperatures shown in Tables 5 and 6 for 60 seconds. Thereafter, immersion development was performed for 30 seconds with a 2.38 mass% TMAH aqueous solution, rinsed with a rinsing material containing a surfactant, and spun dry to obtain a positive pattern.

[0852] The obtained LS pattern was observed with a length-measuring SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, and the sensitivity, EL, LWR, DOF, and collapse limit were evaluated by the following methods. The results are shown in Tables 5 and 6.

[0853] [Sensitivity evaluation]

[0854] The optimum exposure dose Eop (mJ / cm 2 2) for obtaining an LS pattern with a line width of 18 nm and a pitch of 36 nm was determined, and this was defined as the sensitivity. The smaller this value, the higher the sensitivity.

[0855] [EL evaluation]

[0856] From the exposure doses within the range of ±10% (16.2 to 19.8 nm) of the pitch width of 18 nm in the aforementioned LS pattern, EL (unit: %) was calculated by the following formula. The larger this value, the better the performance.

[0857] EL (%) = (|E 1 -E 2 | / Eop) × 100

[0858] E 1 : The optimum exposure dose for an LS pattern with a line width of 16.2 nm and a pitch of 36 nm

[0859] E 2 : The optimum exposure dose for an LS pattern with a line width of 19.8 nm and a pitch of 36 nm

[0860] Eop: The optimum exposure dose for an LS pattern with a line width of 18 nm and a pitch of 36 nm

[0861] [LWR evaluation]

[0862] For the LS pattern obtained by Eop irradiation, measure the dimensions at 10 positions in the longitudinal direction of the line, and obtain three times the standard deviation (σ) (3σ) from the results as the LWR. The smaller this value, the smaller the roughness and the more uniform the line width of the obtained pattern.

[0863] [DOF evaluation]

[0864] For the needle focus depth evaluation, obtain the focus range formed within the range of ±10% (16.2 - 19.8 nm) of the dimension of the aforementioned LS pattern at 18 nm. The larger this value, the wider the focus depth.

[0865] [Evaluation of the collapse limit of the line pattern]

[0866] Measure the line dimensions of each exposure amount at the optimum focus of the aforementioned LS pattern at 10 positions in the longitudinal direction. Define the thinnest line dimension that does not collapse as the collapse limit dimension. The smaller this value, the more excellent the collapse limit.

[0867] [Table 5]

[0868]

[0869]

[0870] [Table 6]

[0871]

[0872]

[0873] From the results shown in Tables 5 and 6, it can be seen that the chemically amplified resist composition using the polymer of the present invention has good sensitivity and excellent EL, LWR, and DOF. Also, it was confirmed that the value of the collapse limit is small, and it can resist the collapse of the pattern even in the formation of fine patterns. Therefore, it is shown that the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[0874] [4] EUV lithography evaluation (2)

[0875] [Examples 4 - 1 to 4 - 25, Comparative Examples 4 - 1 to 4 - 15]

[0876] Each of the chemically amplified resist compositions (R-1 to R-25, CR-1 to CR-15) shown in Tables 3 and 4 was spin-coated on a Si substrate on which Shin-Etsu Chemical Co., Ltd.'s silicon-containing spin-on hard mask SHB-A940 (silicon content: 43 mass%) was formed to a film thickness of 20 nm, and prebaked at 105 °C for 60 seconds using a hot plate to produce a resist film with a film thickness of 50 nm. It was exposed using an EUV scanning exposure machine NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask with a hole pattern on the wafer having a pitch of 46 nm and a +20% deviation) manufactured by ASML, PEB was performed at the temperatures described in Tables 7 and 8 for 60 seconds using a hot plate, and development was carried out for 30 seconds with a 2.38 mass% TMAH aqueous solution to form a hole pattern with a size of 23 nm.

[0877] Using a length-measuring SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, the exposure dose when forming holes with a size of 23 nm was measured and defined as the sensitivity. Also, the sizes of 50 holes at this time were measured, and the three-fold value (3σ) of the standard deviation (σ) calculated from the results was defined as the critical dimension uniformity (CDU). The results are shown in Tables 7 and 8.

[0878] [Table 7]

[0879]

[0880]

[0881] [Table 8]

[0882]

[0883]

[0884] From the results shown in Tables 7 and 8, it was confirmed that the chemically amplified resist composition of the present invention has good sensitivity and excellent CDU.

[0885] [5] Evaluation of dry etching resistance

[0886] [Examples 5-1 to 5-25, Comparative Examples 5-1 to 5-15]

[0887] 2 g of each of the polymers (Polymers P-1 to P-25, Comparative Polymers CP-1 to CP-15) shown in Tables 1 and 2 were dissolved in 10 g of cyclohexanone, and the polymer solution obtained by filtering through a 0.2-μm filter was spin-coated on a Si substrate to form a film with a thickness of 300 nm, and evaluated under the following conditions.

[0888] Etching test using CHF 3 / CF 4 -based gas:

[0889] Using the dry etching apparatus TE-8500P of Tokyo Electron Limited, the film thickness difference of the polymer film before and after etching was determined.

[0890] The etching conditions are as follows.

[0891]

[0892] In this evaluation, the smaller the film thickness difference, that is, the smaller the reduction amount, the higher the etching resistance.

[0893] The results of the dry etching resistance are shown in Tables 9 and 10.

[0894] [Table 9]

[0895]

[0896] [Table 10]

[0897]

[0898]

[0899] From the results shown in Tables 9 and 10, it was confirmed that the polymer of the present invention has excellent dry etching resistance to CHF 3 / CF 4 -based gases.

Claims

1. A polymer comprising a repeating unit represented by the following formula (a), and a repeating unit derived from an onium salt compound containing a fluorosulfonic acid anion having a polymerizable group and an aromatic ring structure substituted with an iodine atom and generating an acid upon exposure, In the formula, m1 is 0 or 1, m2 is an integer of 0 to 3 when m1 is 0, and is an integer of 0 to 5 when m1 is 1, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X A is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * represents an atomic bond with a carbon atom of the main chain, R 1 and R 2 are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and R 1 and R 2 They can also bond to each other and to the carbon atoms to which they are bonded to form rings. R 3 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 3A )(R 3B ), R 3A and R 3B Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. When m2 is 2 or more, the multiple R 3 They may also bond to each other and to the carbon atoms of the aromatic rings to which they are bonded to form a ring. L A 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, L B and L C are each independently an oxygen atom or a sulfur atom, but L A and L C Must be bonded to adjacent carbon atoms in the aromatic ring.

2. The polymer according to claim 1, wherein L B and L C They are all oxygen atoms.

3. The polymer according to claim 1, wherein L A It is a carbonyl group.

4. The polymer according to claim 1, wherein The repeating unit that generates acid upon exposure is represented by the following formula (b): Wherein, n1 is 0 or 1, n2 is 0 or 1, n3 is an integer of 0 to 4, n4 is an integer of 0 to 4, n5 is an integer of 1 to 6, but when n2 is 0, 1≤n4+n5≤4, when n2 is 1, 1≤n4+n5≤6, n6 is an integer of 0 to 4, n7 is 0 or 1, n8 is 0 or 1, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R 11 is a halogen atom, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonthio group having 1 to 20 carbon atoms which may contain a hetero atom, and when n3 is 2, 3 or 4, multiple R 11 They can also bond to each other and to the carbon atoms to which they are bonded to form rings. R 12 is a halogen atom other than an iodine atom, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, a hydrocarbonoxy group having 1 to 20 carbon atoms which may contain a hetero atom, or a hydrocarbonthio group having 1 to 20 carbon atoms which may contain a hetero atom, and when n4 is 2, 3 or 4, a plurality of R 12 They can also bond to each other and to the carbon atoms to which they are bonded to form rings. L D , L E and L F are each independently a single bond, an ether bond, an ester bond, a sulfonate bond, a sulfonamide bond, a carbonate bond or a carbamate bond, X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom, Q 1 and Q 2 are each independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, Q 3 and Q 4 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, Z + It is an onium cation.

5. The polymer according to claim 1, wherein The repeating unit represented by formula (b) is represented by the following formula (b1): In the formula, R A , R 11 , R 12 , L D , L F , Q 1 ~Q 4 , n1~n6 and Z + Same as above.

6. The polymer according to claim 5, wherein The repeating unit represented by formula (b1) is represented by the following formula (b2), In the formula, R A , R 11 , R 12 , L D , Q 1 , Q 2 , n1~n6 and Z + Same as above.

7. The polymer 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), In the formula, 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 also bond to each other and to the sulfur atom to which they are bonded to form a ring.

8. The polymer according to claim 1, further comprising a repeating unit represented by the following formula (c1): In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * represents an atomic bond with 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, a is an integer of 1 to 4, b is an integer of 0 to 3, but 1≤a+b≤5.

9. The polymer according to claim 1, further comprising a repeating unit represented by the following formula (d1) or (d2): In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, Y 1 is a single bond, phenylene, naphthylene, *-C(=O)-OY 11 - or *-C(=O)-NH-Y 11 -, the phenylene or naphthylene group may be substituted by a hydroxyl group, a nitro group, a cyano group, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom, Y 11 is a saturated alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring, Y 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * indicates the atomic bond between the carbon atoms of the main chain, AL 1 and AL 2 are each independently an acid-labile group, R 31 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, c is an integer from 0 to 4.

10. The polymer according to claim 1, further comprising a repeating unit represented by the following formula (e1): In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, Z 1 is a single bond, phenylene, naphthylene, *-C(=O)-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, an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, 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, and the saturated alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring, R 41 It is a group having 1 to 20 carbon atoms, or a structure containing at least one selected from the group consisting of a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-). 11 . A chemically amplified resist composition comprising (A) a base polymer comprising the polymer according to claim 1 . 12 . The chemically amplified resist composition according to claim 11 , further comprising (B) a quencher.

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

14. The chemically amplified resist composition according to claim 11, further comprising (D) an 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 following steps: 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 The exposed resist film is developed 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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