Sulfonium salt monomer, polymer, chemically amplified resist composition, and patterning process

Abstract

The present invention provides a sulfonium salt type monomer, a polymer comprising recurring units derived from the sulfonium salt type monomer, a chemically amplified resist composition comprising the polymer, and a pattern forming process using the chemically amplified resist composition, wherein the chemically amplified resist composition exhibits excellent solvent solubility, high sensitivity, high contrast, and excellent lithography properties such as EL, LWR, CDU, and DOF in photolithography using high-energy radiation, and is resistant to pattern collapse and exhibits excellent etching resistance in fine pattern formation.SOLUTION: A sulfonium salt monomer having the formula (a): SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] As LSIs become more highly integrated and faster, pattern rules are becoming increasingly finer. The expansion of the flash memory market and the increasing storage capacity are driving this trend. The most advanced miniaturization technology is ArF lithography, which is currently used to mass-produce 65nm node devices, and preparations are underway for mass production of next-generation 45nm node devices using ArF immersion lithography. For next-generation 32nm node devices, immersion lithography using an ultra-high NA lens that combines a liquid with a higher refractive index than water, a high-refractive-index lens, and a high-refractive-index resist film; extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm; and double exposure (double patterning lithography) of ArF lithography are candidates for which investigation is underway.

[0003] As miniaturization progresses and approaches the diffraction limit of light, the optical contrast decreases, which in turn causes a decrease in the resolution of hole and trench patterns and a decrease in focus margin in positive resist films.

[0004] As patterns become finer, line width roughness (LWR) of line patterns and dimensional uniformity (CDU) of hole patterns become issues. The effects of uneven distribution and aggregation of base polymers and acid generators, as well as the effects of acid diffusion have been pointed out. Furthermore, as resist films become thinner, LWR tends to increase, and the deterioration of LWR due to thinning accompanying the progress of miniaturization is becoming a serious problem.

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

[0006] To suppress acid diffusion, resist compounds containing repeating units derived from onium salts of sulfonic acids with polymerizable unsaturated bonds have been proposed (Patent Document 1). Such so-called polymer-bound acid generators are characterized by extremely short acid diffusion times because they generate polymeric sulfonic acids upon exposure. Furthermore, increasing the proportion of acid generator can improve sensitivity. Increasing the amount of additive-type acid generators also increases sensitivity, but in this case, the acid diffusion distance also increases. Because acid diffuses unevenly, increased acid diffusion leads to deterioration of LWR and CDU. It can be said that polymer-type acid generators have a high ability to balance sensitivity, LWR, and CDU.

[0007] Because iodine atoms have a very high absorption rate for EUV light with a wavelength of 13.5 nm, the effect of generating secondary electrons from iodine atoms during exposure has been confirmed, and this has attracted attention in EUV lithography. Patent Document 2 describes a photoacid generator in which an iodine atom has been introduced into the anion, and Patent Document 3 describes a polymerizable group-containing photoacid generator in which an iodine atom has been introduced into the anion. While these have been confirmed to improve lithography performance to a certain extent, iodine atoms are not highly soluble in organic solvents, and there is a concern that they may precipitate in the solvent.

[0008] To further suppress acid diffusion, resist compositions have been proposed that use a polymer containing a repeating unit derived from a sulfonium salt of a weak acid having a polymerizable group and a pKa of -0.8 or higher as a polymer-bound quencher (Patent Documents 4 to 7). Patent Document 4 lists carboxylic acids, sulfonamides, phenols, hexafluoroalcohols, etc. as weak acids. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 4425776 [Patent Document 2] Patent No. 6720926 [Patent Document 3] Patent No. 6973274 [Patent Document 4] International Publication No. 2019 / 167737 [Patent Document 5] International Publication No. 2022 / 264845 [Patent Document 6] Japanese Patent Publication No. 2022-115072 [Patent Document 7] Patent No. 7433394 Summary of the Invention [Problem to be solved by the invention]

[0010] There is a need for the development of acid-catalyzed chemically amplified resist compositions that have even higher sensitivity, can improve LWR of line patterns and CDU of hole patterns, and also have excellent etching resistance after pattern formation.

[0011] The present invention has been made in view of the above circumstances, and has an object to provide a sulfonium salt-type monomer for use in a chemically amplified resist composition that exhibits excellent solvent solubility, high sensitivity, high contrast, and excellent lithography performance such as exposure latitude (EL), LWR, CDU, and depth of focus (DOF), particularly when used in photolithography using high-energy rays such as KrF excimer laser light, ArF excimer laser light, electron beam (EB), and EUV, and that is also resistant to pattern collapse and has excellent etching resistance even in the formation of fine patterns; a polymer containing repeating units derived from the sulfonium salt-type monomer; a chemically amplified resist composition containing the polymer; and a pattern formation method using the chemically amplified resist composition. [Means for solving the problem]

[0012] As a result of extensive research into achieving the above-mentioned object, the present inventors have found that by using a polymer containing a repeating unit derived from a sulfonium salt, which has a styrene or vinylnaphthalene structure as a polymerizable group and which contains a carboxylic acid anion having an iodine atom and a sulfonium cation having a pentafluorosulfanyl group (-SF5 group), as a polymer-bonded quencher, it is possible to obtain a chemically amplified resist composition that has excellent solvent solubility, high sensitivity, improved lithography performance such as EL, LWR, CDU, and DOF, high contrast, high resolution, and excellent etching resistance, and has completed the present invention.

[0013] That is, the present invention provides the following sulfonium salt-type monomer, polymer, chemically amplified resist composition, and pattern forming method. 1. A sulfonium salt type monomer represented by the following formula (a): [ka] (In the formula, p is 1, 2, or 3. n1 is 0 or 1. n2 is 1 or 2. n3 is 0, 1, 2, or 3. However, when n1 is 0, 1≦n2+n3≦5, and when n1 is 1, 1≦n2+n3≦7. R1 is a halogen atom, a nitro group, a cyano group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. When n3 is 2 or 3, each R 1 may be the same or different, and two R 1 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 2 is a hydrocarbyl group having 1 to 30 carbon atoms which may contain a halogen atom or a heteroatom. When p is 1, two R 2 may be the same or different. + Two of the three substituents bonded to may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Z - is a carboxylic acid anion having an aromatic vinyl structure and an iodine atom. 2. A sulfonium salt type monomer of 1, which is represented by the following formula (a1): [ka] (In the formula, p, n1~n3, R 1 and Z - is the same as above. n4 is 0 or 1. n5 is 0, 1, 2, 3, 4 or 5. R 3 is a halogen atom, a nitro group, a cyano group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. When n5 is 2 to 5, each R 3 may be the same or different, and two R 3 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 3.Z -is an anion represented by the following formula (Z): [ka] (Wherein, m1 is 0 or 1. m2 is 0, 1, 2, 3 or 4. m3 is 0, 1, 2 or 3. m4 is 0 or 1. m5 is 0, 1, 2, 3 or 4. m6 is 0, 1, 2 or 3. m7 is 0 or 1. m8 is 1, 2, 3 or 4. m9 is 0, 1, 2 or 3. m10 is 0 or 1. m11 is 0 or 1. However, when m1 is 0, 0≦m2+m3+m11≦4, and when m1 is 1, 0≦m2+m3+m11≦6. When m4 is 0, 0≦m5+m6≦4, and when m4 is 1, 0≦m5+m6≦6. When m7 is 0, 0≦m8+m9≦5, and when m7 is 1, 0≦m8+m9≦7. Also, 1≦m2+m5+m8≦4. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 4 , R 5 and R 6 are each independently a halogen atom other than an iodine atom, a nitro group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. When m3 is 2 or 3, each R 4 may be the same or different, and two R 4 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. When m6 is 2 or 3, each R 5 may be the same or different, and two R 5 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. When m9 is 2 or 3, each R 6 may be the same or different, and two R 6 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. LA1 , L A2 , L B1 and L B2 are each independently a single bond, an ether bond, a carbonyl group, an ester bond, a sulfonate ester bond, an amide bond, a sulfonate amide bond, a carbonate bond, or a carbamate bond. X L1 and X L2 are each independently a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. 4. A sulfonium salt type quencher comprising any one of the sulfonium salt type monomers 1 to 3. 5. A polymer containing repeating units derived from the sulfonium salt type quencher of 4. 6. The polymer of 5 further comprising a repeating unit represented by the following formula (b1) or (b2): [ka] (In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 represents a single bond, a phenylene group, a naphthylene group, *-C(=O)-OX 11 - or *-C(=O)-NH-X 11 -, and the phenylene group or naphthylene group may be substituted with a hydroxy group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. 11 is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated hydrocarbylene group may contain a hydroxy group, an ether bond, an ester bond or a lactone ring. X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * indicates a bond to a carbon atom in the main chain. R 11is a halogen atom, a cyano group, a hydroxy group, a nitro group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. 11 may be the same as or different from each other. AL 1 and AL 2 are each independently an acid labile group. a1 is 0, 1, 2, 3 or 4. 7. The polymer of 5 or 6 further comprising a repeating unit represented by the following formula (b3): [ka] (In the formula, b1 is 0 or 1. When b1 is 0, b2 is 0, 1, 2, or 3, and when b1 is 1, b2 is 0, 1, 2, 3, 4, or 5. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 3 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom in the main chain. R 12 and R 13 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 12 and R 13 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 14is a halogen atom, a hydroxy group, a cyano group, a nitro group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom, or -N(R 14A )(R 14B ) is R 14A and R 14B are each independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. When b2 is 2 or more, each R 14 may be the same or different, and multiple R 14 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached. X 4 is a single bond, an aliphatic hydrocarbylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining these. X 5 and X 6 are each independently an oxygen atom or a sulfur atom, provided that X 4 and X 6 are attached to adjacent carbon atoms of an aromatic ring.) 8. A polymer according to any one of 5 to 7, further comprising a repeating unit represented by the following formula (c): [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y 1 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom in the main chain. R 21represents a halogen atom, a nitro group, a cyano group, a carboxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. c1 is 1, 2, 3, or 4. c2 is 0, 1, 2, or 3, provided that 1≦c1+c2≦5. 9. The polymer of any one of 5 to 8, further comprising a repeating unit derived from an onium salt type monomer containing a fluorosulfonate anion having a polymerizable group and at least one iodine atom, and a sulfonium cation. 10. A polymer according to any one of 5 to 9, further comprising a repeating unit represented by the following formula (e): [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z 1 represents a single bond, a phenylene group, a naphthylene group, *-C(=O)-OZ 11 -or*-C(=O)-NH-Z 11 -, and the phenylene group or naphthylene group may be substituted with a hydroxy group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. * represents a bond to a carbon atom in the main chain. Z 11 is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated hydrocarbylene group may contain a hydroxy group, an ether bond, an ester bond or a lactone ring. R 51is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one structure selected from a hydroxy group other than a phenolic hydroxy group, a cyano group, a carbonyl group, a carboxy group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-). 11. (A) A chemically amplified resist composition comprising a base polymer containing any one of the polymers 5 to 10. 12. The chemically amplified resist composition of 11 further comprising (B) an organic solvent. 13. The chemically amplified resist composition of 11 or 12, further comprising (C) a quencher. 14. The chemically amplified resist composition according to any one of 11 to 13, further comprising (D) an acid generator. 15. The chemically amplified resist composition according to any one of 11 to 14, further comprising (E) a surfactant. 16. A pattern forming method comprising the steps of forming a resist film on a substrate using any one of the chemically amplified resist compositions of 11 to 15, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer. 17. The pattern formation method of 16, wherein the high-energy radiation is ArF excimer laser light with a wavelength of 193 nm or KrF excimer laser light with a wavelength of 248 nm, EB, or EUV with a wavelength of 3 to 15 nm. [Effects of the Invention]

[0014] Resist films containing polymers containing repeating units derived from sulfonium salt-type monomers represented by formula (a) exhibit good solvent solubility and, due to the large atomic weight of the iodine atom, exhibit low acid diffusion. This prevents resolution degradation due to acid diffusion blurring and improves LWR and CDU. Furthermore, the absorption of 13.5 nm EUV light by iodine atoms is very strong, generating secondary electrons from the iodine atoms during exposure, resulting in high sensitivity. Furthermore, the -SF5 group contained in the cation is a functional group that promotes solvent solubility and is a strong electron-withdrawing group. By bonding to the aromatic ring of the triarylsulfonium cation, this lowers the LUMO in frontier molecular kinetic theory, making it easier to accept secondary electrons and promoting decomposition of the sulfonium cation. Meanwhile, the carboxylate anion is relatively basic and can effectively trap the acid generated from strong acids. This enables the construction of chemically amplified resist compositions with high sensitivity and improved LWR and CDU. Furthermore, the aromatic ring acts as a good etch-resistant group, making it suitable for fine pattern formation. DETAILED DESCRIPTION OF THE INVENTION

[0015] [Sulfonium salt type monomer] The sulfonium salt type monomer of the present invention is represented by the following formula (a). [ka]

[0016] In formula (a), p is 1, 2 or 3.

[0017] In formula (a), n1 is 0 or 1. When n1 is 0, it is a benzene ring, and when n1 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that n1 is 0, a benzene ring. n2 is 1 or 2. From the viewpoint of raw material procurement, it is preferable that n2 is 1. n3 is 0, 1, 2, or 3. From the viewpoint of raw material procurement, it is preferable that n3 is 0, 1, or 2. However, when n1 is 0, 1≦n2+n3≦5, and when n1 is 1, 1≦n2+n3≦7.

[0018] In formula (a), R 1is a halogen atom, a nitro group, a cyano group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group and hydrocarbylthio 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 a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group; a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, and an aryl group; Examples of the alkyl group include saturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexyl group, a cyclohexylmethyl group, a norbornyl group, and an adamantyl group; alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; unsaturated cyclic aliphatic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexenyl group; aryl groups having 6 to 20 carbon atoms, such as a phenyl group and a naphthyl group; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group, a 1-phenylethyl group, and a 2-phenylethyl group; and groups obtained by combining these groups. Of these, aryl groups are preferred.In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, so that the hydrocarbyl group may contain a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When n3 is 2 or 3, each R. 1 may be the same or different. When n3 is 2 or 3, multiple R 1 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0019] In formula (a), R 2 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom.

[0020] R 2 Specific examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0021] R 2The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; saturated cyclic hydrocarbyl groups having 3 to 30 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; unsaturated cyclic aliphatic hydrocarbyl groups having 3 to 30 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 30 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 30 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these, with aryl groups being preferred. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0022] Also, S + Two of the three substituents bonded to may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, specific examples of the ring structure include those represented by the following formulas: [ka] (In the formula, the dashed lines represent the remaining bonds of the sulfonium cation.)

[0023] The sulfonium salt type monomer represented by formula (a) is preferably one represented by the following formula (a1). [ka] (In the formula, p, n1~n3, R 1 and Z - is the same as above.

[0024] In formula (a1), n4 is 0 or 1. When n4 is 0, it is a benzene ring, and when n4 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, n4 is preferably a benzene ring of 0. n5 is 0, 1, 2, 3, 4, or 5, but from the viewpoint of raw material procurement, n5 is preferably 0, 1, or 2.

[0025] In formula (a1), R 3 is a halogen atom, a nitro group, a cyano group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of these include R 1 Examples of the group represented by the formula (I) include, but are not limited to, the same groups as those exemplified above.

[0026] Examples of the cation of the sulfonium salt type monomer represented by formula (a) include, but are not limited to, those shown below. [ka]

[0027] [ka]

[0028] [ka]

[0029]

change

[0030]

change

[0031]

change

[0032]

change

[0033]

change

[0034]

change

[0035]

change

[0036]

change

[0037]

change

[0038]

change

[0039]

change

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] [ka]

[0045] [ka]

[0046] In formulas (a) and (a1), Z - is a carboxylate anion having an aromatic vinyl structure and an iodine atom. The carboxylate anion is preferably one represented by the following formula (Z): [ka]

[0047] In formula (Z), m1 is 0 or 1. When m1 is 0, it is a benzene ring, and when m1 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, m1 is preferably a benzene ring of 0. m2 is 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, m2 is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2, and even more preferably 0 or 1. m3 is 0, 1, 2, or 3.

[0048] In formula (Z), m4 is 0 or 1. When m4 is 0, it is a benzene ring, and when m4 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, m4 is preferably a benzene ring of 0. m5 is 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, m5 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. m6 is 0, 1, 2, or 3.

[0049] In formula (Z), m7 is 0 or 1. When m7 is 0, it is a benzene ring, and when m7 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, m7 is preferably a benzene ring of 0. m8 is 1, 2, 3, or 4. From the viewpoint of raw material procurement, m8 is preferably 1, 2, or 3, and more preferably 1 or 2. m9 is 0, 1, 2, or 3.

[0050] In formula (Z), m10 is 0 or 1. m11 is 0 or 1.

[0051] However, when m1 is 0, 0≦m2+m3+m11≦4, and when m1 is 1, 0≦m2+m3+m11≦6. When m4 is 0, 0≦m5+m6≦4, and when m4 is 1, 0≦m5+m6≦6. When m7 is 0, 0≦m8+m9≦5, and when m7 is 1, 0≦m8+m9≦7. Furthermore, with regard to the number of iodine atoms in the anion, the greater the number of iodine atoms, the greater the absorption, particularly with respect to EUV. However, since solvent solubility may be poor and precipitation may occur in the resist composition, it is preferable that 1≦m2+m5+m8≦4.

[0052] In formula (Z), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0053] In formula (Z), R 4is a halogen atom other than iodine atom, a nitro group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. The halogen atom other than iodine atom is preferably a fluorine atom, a chlorine atom, or a bromine atom, and more preferably a fluorine atom. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl groups; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, and 4-methyl Examples of the alkyl group include saturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexyl group, a cyclohexylmethyl group, a norbornyl group, and an adamantyl group; alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; unsaturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexenyl group; aryl groups having 6 to 20 carbon atoms, such as a phenyl group and a naphthyl group; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group, a 1-phenylethyl group, and a 2-phenylethyl group; and groups obtained by combining these groups.Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, so that the hydrocarbyl group may contain a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When m3 is 2 or 3, each R. 4 may be the same as or different from each other.

[0054] Also, when m3 is 2 or 3, two R 4 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. Furthermore, some or all of the hydrogen atoms in the ring 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 some of the -CH- groups in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the ring containing a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0055] In formula (Z), R 5is a halogen atom other than iodine atom, a nitro group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of the halogen atom other than iodine atom include a fluorine atom, a chlorine atom, and a bromine atom. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 4 When m6 is 2 or 3, each R 5 may be the same as or different from each other.

[0056] Also, when m6 is 2, two R 5 However, they may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0057] In formula (Z), R 6 is a halogen atom other than iodine atom, a nitro group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of the halogen atom other than iodine atom include a fluorine atom, a chlorine atom, and a bromine atom. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 4 When m9 is 2 or 3, each R 6 may be the same as or different from each other.

[0058] Also, when m9 is 2, two R 6However, they may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0059] In formula (Z), L A1 , L A2 , L B1 and L B2 are each independently a single bond, an ether bond, a carbonyl group, an ester bond, a sulfonate ester bond, an amide bond, a sulfonate amide bond, a carbonate bond, or a carbamate bond. A1 is preferably a single bond, an ether bond, an ester bond or a sulfonate ester bond, and more preferably an ether bond, an ester bond or a sulfonate ester bond. A2 is preferably a single bond, an ether bond, an ester bond, an amide bond, a sulfonic acid amide bond, or a sulfonic acid ester bond, and more preferably an ester bond or a sulfonic acid ester bond. B1 is preferably a single bond, an ether bond, an ester bond, an amide bond or a sulfonate ester bond, and more preferably a single bond, an ether bond or an ester bond. B2 is preferably a single bond, an ether bond, an ester bond, an amide bond or a sulfonate ester bond, and more preferably a single bond, an ether bond or an ester bond.

[0060] If m11 is 1, L A1 and L A2 are preferably bonded to adjacent carbon atoms of the aromatic ring. In this case, the substituent containing the fluorosulfonate anion structure and the substituent containing the aromatic ring substituted with an iodine atom are located closer in space, which is expected to result in higher sensitivity.

[0061] In formula (Z), X L1 and X L2are each independently a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include an alkanediyl group, a cyclic saturated hydrocarbylene group, and an arylene group. Specific examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom.

[0062] X L1 and X L2 Specific examples of the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a hetero atom, represented by the formula (I), include, but are not limited to, those shown below. In the following formula, * represents L A1 and L B1 , or L A2 and L B2 It is a combination of. [ka]

[0063] [ka]

[0064] [ka]

[0065] [ka]

[0066] Of these, X L -0~X L -22, X L -29~X L -34 and X L -47~X L -58 is preferred.

[0067] Specific examples of the anion of the onium salt type monomer represented by formula (a) include, but are not limited to, those shown below. A is the same as above, and Me is a methyl group. The bonding positions of the various substituents on the aromatic ring may be interchanged across the aromatic ring. [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076]

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[0077]

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[0078]

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[0172] [ka]

[0173] [ka]

[0174] Other specific examples of the anion of the onium salt monomer represented by formula (a) include those described in

[0049] ,

[0054] to

[0056] , and

[0062] to

[0064] of Japanese Patent No. 7433394, but are not limited to these.

[0175] Specific examples of the sulfonium salt type monomer of the present invention include any combination of the above-mentioned anions and cations.

[0176] The sulfonium salt monomer of the present invention can be synthesized by a known method, specifically, the method described in

[0402] to

[0405] of Japanese Patent No. 7433394, but the synthesis method is not limited thereto.

[0177] [polymer] The polymer of the present invention contains a repeating unit derived from a sulfonium salt type monomer represented by formula (a) (hereinafter also referred to as repeating unit a).

[0178] The polymer of the present invention is a polymer-bound quencher that functions as a quencher and a base polymer in a chemically amplified resist composition. A structural feature of the polymer of the present invention is that it contains a repeating unit derived from the sulfonium salt-type monomer of the present invention, which has a benzene or naphthalene structure directly bonded to the main chain and a salt structure containing a carboxylic acid anion having an iodine atom and a sulfonium cation having an -SF5 group. Because iodine atoms have extremely high absorption of EUV light with a wavelength of 13.5 nm, secondary electrons are generated during exposure, and the energy of the secondary electrons is transferred to the acid generator, promoting decomposition and thereby increasing sensitivity. Polymerizable groups consisting of styrene or vinylnaphthalene structures are more rigid than polymerizable groups such as methacrylate esters, improving the glass transition temperature (Tg) of the polymer. Interactions between aromatic rings within or between base polymers (π-π stacking effect) result in the regular arrangement of the base polymer, which is thought to exhibit resistance to pattern collapse in a developer even during fine pattern formation. Furthermore, the aromatic ring directly attached to the main chain provides excellent etching resistance during the etching process after fine pattern formation. Although solvent solubility decreases with increasing the number of iodine atoms, the inclusion of an -SF5 group in the cation ensures solvent solubility. Furthermore, the -SF5 group is a strong electron-withdrawing group, and by substituting it into the aromatic ring of the triarylsulfonium cation, it lowers the LUMO in frontier molecular kinetic theory, making it easier to accept secondary electrons and promoting the decomposition of the sulfonium cation. The carboxylate anion is relatively basic and can effectively trap the acid generated from strong acids. This synergistic effect enables high sensitivity, improved LWR and CDU, and pattern formation that is resistant to pattern collapse, making this compound particularly suitable as a material for chemically amplified positive resist compositions.

[0179] The polymer may further include a repeating unit represented by the following formula (b1) (hereinafter also referred to as repeating unit b1) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit b2). [ka]

[0180] In formulas (b1) and (b2), R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0181] In formula (b1), X 1 represents a single bond, a phenylene group, a naphthylene group, *-C(=O)-OX 11 - or *-C(=O)-NH-X 11 -, and the phenylene group or naphthylene group may be substituted with a hydroxy group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. 11 is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the saturated hydrocarbylene group may contain a hydroxy group, an ether bond, an ester bond, or a lactone ring. * represents a bond to a carbon atom in the main chain.

[0182] In formula (b2), X 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom in the main chain. R 11 is a halogen atom, a cyano group, a hydroxy group, a nitro group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. a1 is 0, 1, 2, 3 or 4, preferably 0 or 1. When a1 is 2 or more, each R 11 may be the same as or different from each other.

[0183] In formulas (b1) and (b2), AL 1 and AL 2 are each independently an acid labile group. Specific examples of the acid labile group include, but are not limited to, those described in JP-A Nos. 2013-80033 and 2013-83821.

[0184] Typical examples of the acid labile group include those represented by the following formulae (AL-1) to (AL-3). [ka] (In the formula, * represents a bond.)

[0185] In formulas (AL-1) and (AL-2), R L1 and R L2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, or an iodine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group preferably has 1 to 20 carbon atoms.

[0186] In formula (AL-1), a2 represents an integer of 0 to 10, and is preferably 1, 2, 3, 4 or 5.

[0187] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. L2 , R L3 and R L4 Any two of these may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0188] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a fluorine atom, or an iodine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. L5 , R L6 and R L7 Any two of these may be bonded to each other together with the carbon atoms to which they are bonded to form a ring having 3 to 20 carbon atoms. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0189] Specific examples of the repeating unit b1 include, but are not limited to, the following: A and AL 1 is the same as above. [ka]

[0190] [ka]

[0191] [ka]

[0192] [ka]

[0193] [ka]

[0194] [ka]

[0195] [ka]

[0196] Specific examples of the repeating unit b2 include, but are not limited to, those shown below. A and AL 2 is the same as above. [ka]

[0197] [ka]

[0198] [ka]

[0199] The polymer may further contain a repeating unit represented by the following formula (b3) (hereinafter also referred to as repeating unit b3). [ka]

[0200] In formula (b3), b1 is 0 or 1. When b1 is 0, it is a benzene ring, and when b1 is 1, it is a naphthalene ring; however, from the viewpoint of solvent solubility, it is preferable that b1 is a benzene ring of 0. When b1 is 0, b2 is 0, 1, 2, or 3, and when b1 is 1, it is 0, 1, 2, 3, 4, or 5. From the viewpoint of raw material procurement, b2 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0201] In formula (b3), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0202] In formula (b3), X 3 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom in the main chain. Among these, a single bond or *-C(=O)-O- is preferred, and a single bond is more preferred.

[0203] In formula (b3), R 12 and R 13are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, and 4-methyl Examples of the alkyl group include saturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexyl group, a cyclohexylmethyl group, a norbornyl group, and an adamantyl group; alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; unsaturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexenyl group; aryl groups having 2 to 20 carbon atoms, such as a phenyl group and a naphthyl group; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group, a 1-phenylethyl group, and a 2-phenylethyl group; and groups obtained by combining these groups. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0204] Also, R 12 and R 13may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. Furthermore, some or all of the hydrogen atoms in the ring 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 some of the -CH- groups in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the ring containing a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0205] In formula (b3), R 14 is a halogen atom, a hydroxy group, a cyano group, a nitro group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom, or -N(R 14A )(R 14B ) is R 14A and R 14B are each independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. The 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 hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group, hydrocarbyloxycarbonyl group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include R 12 and R 13Examples of the hydrocarbyl group include the same as those exemplified above. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. When b2 is 2 or more, each R 14 may be the same as or different from each other.

[0206] Also, when b2 is 2 or more, multiple R 14 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. Furthermore, some or all of the hydrogen atoms in the ring 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 some of the -CH- groups in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the ring containing a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0207] In formula (b3), X 4 is a single bond, an aliphatic hydrocarbylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining these. Of these, a single bond, a carbonyl group, or a sulfonyl group is preferred from the viewpoint of raw material procurement, and a single bond or a carbonyl group is more preferred from the viewpoint of the polar group generated after the reaction.

[0208] In formula (b3), X 5 and X 6 are each independently an oxygen atom or a sulfur atom, provided that X 4 and X 6 are attached to adjacent carbon atoms of the aromatic ring. 5 and X 6 may be the same or different from each other, but from the viewpoint of reactivity, X 5 and X 6 and are preferably both oxygen atoms.

[0209] Specific examples of the repeating unit b3 include, but are not limited to, those shown below. A is the same as above, and Me is a methyl group. The bonding positions of the various substituents on the aromatic ring may be interchanged. [ka]

[0210] [ka]

[0211] [ka]

[0212] [ka]

[0213] [ka]

[0214] [ka]

[0215]

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[0258] [ka]

[0259] The base polymer preferably further contains a repeating unit represented by the following formula (c) (hereinafter also referred to as repeating unit c). [ka]

[0260] In formula (c), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom in the main chain. R 21 is a halogen atom, a nitro group, a cyano group, a carboxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. c1 is 1, 2, 3, or 4. c2 is 0, 1, 2, or 3, provided that 1≦c1+c2≦5.

[0261] Specific examples of the repeating unit c include, but are not limited to, those shown below. A is the same as above. [ka]

[0262] [ka]

[0263] [ka]

[0264] [ka]

[0265] [ka]

[0266] The base polymer preferably further contains a repeating unit (hereinafter also referred to as repeating unit d) derived from an onium salt type monomer containing a fluorosulfonate anion having a polymerizable group and at least one iodine atom and a sulfonium cation.

[0267] Specific examples of the anion of repeating unit d include structures described in

[0023] to

[0029] of Japanese Patent No. 6973274,

[0032] to

[0038] of JP-A No. 2023-172928, and

[0032] to

[0047] of JP-A No. 2024-043941.

[0268] Furthermore, specific examples of the anion of the repeating unit d are also preferred, including those represented by the following formula (d1). [ka]

[0269] In formula (d1), d1 is 0 or 1. When d1 is 0, it is a benzene ring, and when d1 is 1, it is a naphthalene ring; however, from the viewpoint of solvent solubility, d1 is preferably a benzene ring of 0. d2 is 0 or 1. When d2 is 0, it is a benzene ring, and when d2 is 1, it is a naphthalene ring; however, from the viewpoint of solvent solubility, d2 is preferably a benzene ring of 0. d3 is 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, d3 is preferably 0, 1, or 2, and more preferably 0 or 1. d4 is 0, 1, 2, 3, or 4, but is preferably 0, 1, 2, or 3, more preferably 0, 1, or 2, and even more preferably 0 or 1. d5 is 1, 2, 3, 4, 5, or 6. The greater the number of iodine atoms in the anion structure, the greater the absorption, particularly with respect to EUV. However, solvent solubility may be poorer, which may lead to precipitation in the resist composition. Therefore, d5 is preferably 1, 2, or 3, and more preferably 1 or 2. However, when d2 is 0, 1≦d4+d5≦4, and when d2 is 1, 1≦d4+d5≦6. d6 is 0, 1, 2, 3, or 4, and is preferably 0, 1, 2, or 3, and more preferably 1.

[0270] In formula (d1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0271] In formula (d1), the iodine atom in the aromatic ring of the anion is L B Since the iodine atom is an element with a large atomic radius, rotation of the bond axis between the aromatic ring to which the polymerizable group is bonded and the aromatic ring to which the iodine atom is bonded is suppressed, thereby improving the rigidity of the polymer.

[0272] In formula (d1), R 31is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and more preferably a fluorine atom or an iodine atom. The hydrocarbyl 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 a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, or an icosyl group; a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, or a 4-methyl Examples of the alkyl group include saturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexyl group, a cyclohexylmethyl group, a norbornyl group, and an adamantyl group; alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; unsaturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexenyl group; aryl groups having 2 to 20 carbon atoms, such as a phenyl group and a naphthyl group; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group, a 1-phenylethyl group, and a 2-phenylethyl group; and groups obtained by combining these groups. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, resulting in the hydrocarbyl group containing a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When d3 is 2, 3 or 4, each R 31 may be the same as or different from each other.

[0273] Also, when d3 is 2, 3 or 4, multiple R31 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. Furthermore, some or all of the hydrogen atoms in the ring 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 some of the -CH- groups in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the ring containing a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0274] In formula (d1), R 32 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom other than iodine atom or a heteroatom. Specific examples of the halogen atom other than iodine atom include a fluorine atom, a chlorine atom, and a bromine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 31 When d4 is 2, 3 or 4, each R 32 may be the same as or different from each other.

[0275] Also, when d4 is 2, 3 or 4, multiple R 32 However, they may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0276] In formula (d1), L C , L D and L Eare each independently a single bond, an ether bond, an ester bond, a sulfonate ester bond, a sulfonate amide bond, a carbonate bond, or a carbamate bond. C is preferably a single bond, an ether bond, an ester bond or a sulfonate ester bond, and more preferably an ester bond or a sulfonate ester bond. D is preferably a single bond, an ether bond or an ester bond, and more preferably a single bond. E The bond is preferably a single bond, an ether bond, an ester bond or a sulfonate ester bond, and more preferably an ether bond or an ester bond.

[0277] In formula (d1), X L3 is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include an alkanediyl group, a cyclic saturated hydrocarbylene group, and an arylene group. Specific examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom. X L3 Specific examples of the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a hetero atom, which is represented by the formula (Z), include X L1 and X L2 The X exemplified as specific examples of the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a hetero atom is L -0~X L Among these, X L -0~X L -22, X L -29~X L -34 and X L -47~X L -58 is preferred.

[0278] From the viewpoint of the rigidity of the resulting polymer, X L3 is preferably a single bond.

[0279] In formula (d1), Q 1and Q 2 are each independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. As the fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a trifluoromethyl group is preferred.

[0280] In formula (d1), Q 3 and Q 4 are each independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. As the fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a trifluoromethyl group is preferred. 3 and Q 4 is more preferably a fluorine atom.

[0281] In formula (d1), -[C(Q 1 )(Q 2 )] d6 -C(Q 3 )(Q 4 )-SO3 - Specific examples of the partial structure represented by the formula (I) are preferably, but are not limited to, those shown below. In the formula (I), * represents L C Represents a bond with . [ka]

[0282] Of these, Acid-1 to Acid-7 are preferred, and Acid-1 to Acid-3, Acid-6 and Acid-7 are more preferred.

[0283] The anion represented by formula (d1) is preferably an anion represented by the following formula (d1-1): [ka] (In the formula, d1~d6, R A , R 31 , R 32 , L C , L E , Q 1 ~Q 4 and Z + is the same as above.)

[0284] The anion represented by formula (d1-1) is preferably an anion represented by the following formula (d1-2): [ka] (In the formula, d1~d6, R A , R 31 , R 32 , L C , Q 1 , Q 2 and Z + is the same as above.)

[0285] Specific examples of the anion represented by formula (d1) include, but are not limited to, the following: A and Q 1 is the same as above, and Me is a methyl group. The bonding positions of the various substituents on the aromatic ring may be interchanged. [ka]

[0286] [ka]

[0287] [ka]

[0288] [ka]

[0289] [ka]

[0290] [ka]

[0291]

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[0292]

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[0293]

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[0294]

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[0295]

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[0296]

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[0297]

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[0298]

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[0299]

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[0300]

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[0301]

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[0302]

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[0303]

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[0304]

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[0305]

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[0306]

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[0307]

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[0308]

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[0309]

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[0310]

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[0311]

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[0312]

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[0313]

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[0314]

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[0315]

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[0316]

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[0317]

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[0318]

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[0319]

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[0320]

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[0321]

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[0322]

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[0323]

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[0324]

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[0325]

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[0326]

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[0327]

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[0328]

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[0329]

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[0330]

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[0331]

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[0332]

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[0333] [ka]

[0334] [ka]

[0335] [ka]

[0336] [ka]

[0337] [ka]

[0338] [ka]

[0339] [ka]

[0340] [ka]

[0341] [ka]

[0342] Furthermore, the anion of the repeating unit d is also preferably one represented by the following formula (d2). [ka]

[0343] In formula (d2), d11 is 0 or 1. When d11 is 0, it is a benzene ring, and when d11 is 1, it is a naphthalene ring; however, from the viewpoint of solvent solubility, it is preferable that d11 is a benzene ring of 0. d12 is 1, 2, 3, or 4. From the viewpoint of raw material procurement, d12 is preferably 1, 2, or 3, more preferably 1 or 2, and even more preferably 1. d13 is 0, 1, or 2. However, when d11 is 0, 1≦d12+d13≦4, and when d11 is 1, 1≦d12+d13≦6.

[0344] In formula (d2), d14 is 0 or 1. When d14 is 0, it is a benzene ring, and when d14 is 1, it is a naphthalene ring. However, from the viewpoint of solvent solubility, d14 is preferably a benzene ring of 0. d15 is 1, 2, 3, or 4, and preferably 1, 2, or 3. The greater the number of iodine atoms in the anion structure, the higher the absorption, particularly of EUV. However, since solvent solubility is poor and there is a concern of precipitation in the resist composition, the number of iodine atoms in the anion is preferably 2, 3, 4, or 5, and more preferably 2, 3, or 4. d16 is 0, 1, or 2. However, when d14 is 0, 1≦d15+d16≦4, and when d14 is 1, 1≦d15+d16≦6.

[0345] In formula (d2), d17 is 0, 1, 2, 3 or 4, preferably 0, 1, 2 or 3, more preferably 1, 2 or 3, and even more preferably 1.

[0346] In formula (d2), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0347] In formula (d2), R 33is a halogen atom other than iodine atom, a nitro group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. The halogen atom other than iodine atom is preferably a fluorine atom, a chlorine atom, or a bromine atom, and more preferably a fluorine atom. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl groups; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, and 4-methyl Examples of the alkyl group include saturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexyl group, a cyclohexylmethyl group, a norbornyl group, and an adamantyl group; alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; unsaturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexenyl group; aryl groups having 6 to 20 carbon atoms, such as a phenyl group and a naphthyl group; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group, a 1-phenylethyl group, and a 2-phenylethyl group; and groups obtained by combining these groups. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.When d13 is 2, each R. 33 may be the same as or different from each other.

[0348] Also, when d13 is 2, two R 33 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. Furthermore, some or all of the hydrogen atoms in the ring 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 some of the -CH- groups in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the ring containing a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0349] In formula (d2), R 34 is a halogen atom other than iodine atom, a nitro group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of the halogen atom other than iodine atom include a fluorine atom, a chlorine atom, and a bromine atom. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 33 When d16 is 2, the hydrocarbyl group represented by each R 34 may be the same as or different from each other.

[0350] Also, when d16 is 2, two R 34However, they may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0351] In formula (d2), L F1 , L F2 , L G1 and L G2 are each independently a single bond, an ether bond, an ester bond, a sulfonate ester bond, an amide bond, a sulfonate amide bond, a carbonate bond, or a carbamate bond. F1 is preferably a single bond, an ether bond, an ester bond or a sulfonate ester bond, and more preferably an ester bond or a sulfonate ester bond. F2 is preferably a single bond, an ether bond, an ester bond or a sulfonate ester bond, and more preferably an ester bond or a sulfonate ester bond. G1 is preferably a single bond, an ether bond, an ester bond or a sulfonate ester bond, and more preferably a single bond, an ether bond or an ester bond. G2 is preferably a single bond, an ether bond, an ester bond or a sulfonate ester bond, and more preferably a single bond, an ether bond or an ester bond.

[0352] L F1 and L F2 are preferably bonded to adjacent carbon atoms of the aromatic ring. In this case, the substituent containing the fluorosulfonate anion structure and the substituent containing the aromatic ring substituted with an iodine atom are located closer in space, which is expected to result in higher sensitivity.

[0353] In formula (d2), X L4 and X L5are each independently a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include an alkanediyl group, a cyclic saturated hydrocarbylene group, and an arylene group. Specific examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom. X L4 and X L Specific examples of the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a hetero atom, which is represented by the formula (Z), include X L1 and X L2 The X exemplified as specific examples of the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a hetero atom is L -0~X L Among these, X L -0~X L -22, X L -29~X L -34 and X L -47~X L -58 is preferred.

[0354] In formula (d2), Q 11 and Q 12 are each independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. As the fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a trifluoromethyl group is preferred.

[0355] In formula (d2), Q 13 and Q 14 are each independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. As the fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a trifluoromethyl group is preferred. 13 and Q 14 is more preferably a fluorine atom.

[0356] In formula (d2), -[C(Q 11 )(Q 12 )] d17 -C(Q 13 )(Q 14)-SO3 - Specific examples of the partial structure represented by the formula (I) are preferably, but are not limited to, those shown below. In the formula (I), * represents L G1 Represents a bond with . [ka]

[0357] Of these, Acid-1 to Acid-7 are preferred, and Acid-1 to Acid-3, Acid-6 and Acid-7 are more preferred.

[0358] The anion represented by formula (d2) is preferably an anion represented by the following formula (d2-1): [ka] (In the formula, R A , R 33 , R 34 , L F1 , L F2 , Q 11 ~Q 14 and d11 to d17 are the same as above.)

[0359] The anion represented by formula (d2-1) is preferably an anion represented by the following formula (d2-2): [ka] (In the formula, R A , R 33 , R 34 , L F2 , Q 11 , Q 12 and d11 to d17 are the same as above.)

[0360] Specific examples of the anion represented by formula (d2) include, but are not limited to, those shown below. In the following formula, R A and Q 11 is the same as above, and Me is a methyl group. The bonding positions of the various substituents on the aromatic ring may be interchanged.

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[0361]

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[0362]

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[0363]

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[0364]

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[0365]

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[0366]

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[0367]

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[0368]

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[0369]

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[0370]

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[0371]

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[0372]

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[0373]

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[0374]

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[0375]

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[0376]

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[0377]

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[0378]

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[0379]

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[0380]

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[0381]

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[0382]

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[0383]

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[0384]

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[0385]

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[0386]

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[0387]

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[0388]

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[0389]

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[0390]

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[0391]

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[0392]

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[0393]

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[0394]

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[0395]

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[0396]

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[0397]

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[0398]

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[0399]

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[0400]

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[0401]

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[0402]

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[0403]

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[0404]

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[0405]

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[0406]

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[0407]

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[0408]

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[0409]

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[0410]

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[0411]

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[0412]

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[0413] [ka]

[0414] [ka]

[0415] [ka]

[0416] [ka]

[0417] [ka]

[0418] [ka]

[0419] Specific examples of the sulfonium cation of the repeating unit d include those exemplified as sulfonium cations of the sulfonium salt type monomer represented by formula (a), those described in paragraphs

[0102] to

[0125] of JP-A No. 2024-3744, and those described in paragraphs

[0070] to

[0085] of JP-A No. 2023-169812.

[0420] Furthermore, the sulfonium cation of the repeating unit d is also preferably a sulfonium cation represented by the following formula (d3). [ka]

[0421] In formula (d3), d21 is 0 or 1. When d21 is 0, it is a benzene ring, and when d21 is 1, it is a naphthalene ring, although from the viewpoint of solvent solubility, it is preferably a benzene ring with d21 being 0. d22 is 0 or 1. When d22 is 0, it is a benzene ring, and when d22 is 1, it is a naphthalene ring, although from the viewpoint of solvent solubility, it is preferably a benzene ring with d21 being 0. d23 is 0 or 1. When d23 is 0, it is a benzene ring, and when d23 is 1, it is a naphthalene ring, although from the viewpoint of solvent solubility, it is preferably a benzene ring with d23 being 0.

[0422] In formula (d3), d24 is 0, 1, 2, 3, or 4. As the number of iodine atoms in the cation structure increases, absorption, particularly of EUV, increases. However, solvent solubility decreases, raising concerns about precipitation in the resist composition. Therefore, d24 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0423] In formula (d3), d25 is 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, d25 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. d26 is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material procurement, d26 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. d27 is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material procurement, d27 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0424] In formula (d3), d28 is 0, 1, or 2. From the viewpoint of raw material procurement, d28 is preferably 0 or 1. d29 is 0, 1, or 2. From the viewpoint of raw material procurement, d29 is preferably 0 or 1. d30 is 0, 1, or 2. From the viewpoint of raw material procurement, d30 is preferably 0 or 1.

[0425] In formula (d3), d31 is 0 or 1. When d31 is 0, it is a benzene ring, and when d31 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that d31 is 0 and is a benzene ring.

[0426] In formula (d3), d32 is 0, 1, 2, 3, or 4. As the number of iodine atoms in the cation structure increases, absorption, particularly of EUV, increases. However, solvent solubility decreases, raising concerns about precipitation in the resist composition. Therefore, d32 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0427] In formula (d3), d33 is 0, 1, or 2. From the viewpoint of raw material procurement, d33 is preferably 0 or 1. d34 is 0, 1, or 2. From the viewpoint of synthesis, d34 is preferably 0 or 1.

[0428] However, when d21 is 0, 0≦d26+d29≦4, and when d21 is 1, 0≦d26+d29≦6. When d22 is 0, 0≦d27+d30≦4, and when d22 is 1, 0≦d27+d30≦6. When d23 is 0, 1≦d24+d25+d28+d34≦4, and when d23 is 1, 1≦d24+d25+d28+d4≦6. When d31 is 0, 0≦d32+d33≦4, and when d31 is 1, 0≦d32+d33≦6. Also, d24+d32≧1.

[0429] In formula (d3), R F1 ~R F3 are each independently a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms. Among these, a trifluoromethyl group, a trifluoromethoxy group, or a trifluorothiomethoxy group is preferred. When d25 is 2 or greater, each R F1 may be the same or different, and when d26 is 2 or more, each R F2 may be the same or different, and when d27 is 2 or more, each RF3 may be the same or different from each other.

[0430] In formula (d3), R 41 ~R 44 is a halogen atom other than iodine and fluorine atoms, a nitro group, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 1 In addition, some or all of the hydrogen atoms in the hydrocarbyl moiety of the hydrocarbyl group, hydrocarbyloxy group, and hydrocarbylthio group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, so that the hydrocarbyl group may contain a hydroxy group, cyano group, fluorine atom, chlorine atom, bromine atom, iodine atom, carbonyl group, ether bond, ester bond, sulfonate ester bond, carbonate bond, lactone ring, sultone ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl group, etc.

[0431] Also, when d28 is 2, two R 41 may be the same or different, and two R 41 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, and when d29 is 2, two R 42 may be the same or different, and two R 42 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, and when d30 is 2, two R 43 may be the same or different, and two R 43may be bonded to each other to form a ring together with the carbon atoms to which they are bonded, and when d33 is 2, two R 44 may be the same or different, and two R 44 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. Furthermore, some or all of the hydrogen atoms in the ring 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 some of the -CH- groups in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the ring containing a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0432] In addition, S in the sulfonium cation represented by formula (d3) + The aromatic rings directly bonded to S + In this case, specific examples of the ring structure include those represented by the following formulas: [ka] (In the formula, the dashed lines represent bonds.)

[0433] In formula (d3), L H1 and L H2 are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate ester bond, a sulfonate amide bond, a carbonate bond, or a carbamate bond. H1 is preferably a single bond, an ether bond, an ester bond or a sulfonate ester bond, and more preferably an ester bond or a sulfonate ester bond. H2is preferably a single bond, an ether bond or an ester bond, and more preferably a single bond.

[0434] In formula (d3), X L6 is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include an alkanediyl group, a cyclic saturated hydrocarbylene group, and an arylene group. Specific examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom. X L6 Specific examples of the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a hetero atom, which is represented by the formula (Z), include X L1 and X L2 The X exemplified as specific examples of the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a hetero atom is L -0~X L Among these, X L -0~X L -22, X L -29~X L -34 and X L -47~X L -58 is preferred.

[0435] The sulfonium cation represented by formula (d3) is preferably one represented by the following formula (d3-1). [ka] (In the formula, d24~d30, d32~d34, R F1 ~R F3 , R 41 ~R 44 , L H1 , L H2 and X L6 is the same as above.)

[0436] The sulfonium cation represented by formula (d3-1) is preferably one represented by the following formula (d3-2). [ka] (In the formula, d24~d30, R F1 ~R F3 and R ct6 ~R ct8 is the same as above.)

[0437] Specific examples of the sulfonium cation represented by formula (3) include, but are not limited to, the following: In the following formula, Me is a methyl group. [ka]

[0438] [ka]

[0439] [ka]

[0440] [ka]

[0441] [ka]

[0442] [ka]

[0443] [ka]

[0444] [ka]

[0445] [ka]

[0446]

change

[0447]

change

[0448]

change

[0449]

change

[0450]

change

[0451]

change

[0452]

change

[0453]

change

[0454]

change

[0455]

change

[0456] [ka]

[0457] [ka]

[0458] [ka]

[0459] [ka]

[0460] [ka]

[0461] [ka]

[0462] [ka]

[0463] [ka]

[0464] [ka]

[0465] The base polymer preferably further contains a repeating unit represented by the following formula (e) (hereinafter also referred to as repeating unit e). [ka]

[0466] In formula (e), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 represents a single bond, a phenylene group, a naphthylene group, *-C(=O)-OZ 11 -or*-C(=O)-NH-Z 11 -, and the phenylene group or naphthylene group may be substituted with a hydroxy group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. * represents a bond to a carbon atom in the main chain. Z 11 R is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the saturated hydrocarbylene group may contain a hydroxy group, an ether bond, an ester bond, or a lactone ring. 51 is a group having 1 to 20 carbon atoms and containing at least one structure selected from a hydrogen atom, a hydroxy group other than a phenolic hydroxy group, a cyano group, a carbonyl group, a carboxy group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic anhydride (-C(=O)-OC(=O)-).

[0467] Specific examples of the repeating unit e include, but are not limited to, those shown below. A is the same as above. [ka]

[0468] [ka]

[0469] [ka]

[0470]

change

[0471]

change

[0472]

change

[0473]

change

[0474]

change

[0475]

change

[0476]

change

[0477]

change

[0478]

change

[0479]

change

[0480]

change

[0481] [ka]

[0482] [ka]

[0483] As the repeating unit e, in ArF lithography, those having a lactone ring as a polar group are particularly preferred, and in KrF lithography, EB lithography and EUV lithography, those having a phenol moiety are preferred.

[0484] The polymer may further contain a repeating unit having a structure in which a hydroxy group is protected by an acid labile group (hereinafter also referred to as repeating unit f). The repeating unit e is not particularly limited as long as it has one or more structures in which a hydroxy group is protected and the protecting group is decomposed by the action of an acid to generate a hydroxy group, but is preferably one represented by the following formula (f): [ka]

[0485] In formula (f), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 61 R is a hydrocarbon group having 1 to 30 carbon atoms and a valence of (e+1), which may contain a heteroatom. 62 is an acid labile group; e is 1, 2, 3 or 4.

[0486] In formula (f), R 62 The acid labile group represented by R may be any group that can be deprotected by the action of an acid to generate a hydroxy group. 62 Although the structure is not particularly limited, an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (f1), and the like are preferred, and an alkoxymethyl group represented by the following formula (f1) is particularly preferred. [Chemical formula] (In the formula, * represents a bond. R 63 is a hydrocarbyl group having 1 to 15 carbon atoms.)

[0487] R 62 Examples of the acid-labile group represented by, the alkoxymethyl group represented by formula (f1), and the repeating unit f are the same as those exemplified in the description of the repeating unit d described in JP-A-2020-111564.

[0488] The base polymer may further contain a repeating unit g derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or a derivative thereof. Specific examples of the monomer that gives the repeating unit g include, but are not limited to, those shown below. [Chemical formula] <X

[0489] The base polymer may further contain a repeating unit h derived from styrene, indane, vinyl pyridine or vinyl carbazole.

[0490] In the polymer of the present invention, the content ratios of the repeating units a, b1, b2, b3, c, d, e, f, g and h are preferably 0 < a ≤ 0.4, 0 < b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 ≤ b3 ≤ 0.6, 0 < c ≤ 0.6, 0 ≤ d ≤ 0.4, 0 ≤ e ≤ 0.6, 0 ≤ f ≤ 0.3, 0 ≤ g ≤ 0.3 and 0 ≤ h ≤ 0.3, and more preferably 0 < a ≤ 0.3, 0 < b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 ≤ b3 ≤ 0.5, 0 < c ≤ 0.5, 0 ≤ d ≤ 0.3, 0 ≤ e ≤ 0.5, 0 ≤ f ≤ 0.2, 0 ≤ g ≤ 0.2 and 0 ≤ h ≤ 0.2. However, a + b1 + b2 + b3 + c + d + e + f + g + h ≤ 1.0.

[0491] The weight-average molecular weight (Mw) of the polymer is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. When Mw is within this range, sufficient etching resistance is obtained, and there is no risk of a decrease in resolution due to an inability to ensure a difference in dissolution rate before and after exposure. In the present invention, Mw is a value measured in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent.

[0492] Furthermore, since the influence of Mw / Mn on the molecular weight distribution of the polymer tends to become greater as the pattern rule becomes finer, in order to obtain a resist composition that is suitable for use with fine pattern dimensions, it is preferable that Mw / Mn be a narrow distribution of 1.0 to 2.0. Within this range, there is little low-molecular-weight or high-molecular-weight polymer, and there is no risk of foreign matter being observed on the pattern or deterioration of the pattern shape after exposure.

[0493] The polymer can be synthesized, for example, by polymerizing a monomer that provides the repeating unit described above in an organic solvent with the addition of a radical polymerization initiator by heating.

[0494] Specific examples of organic solvents used during polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyrolactone (GBL). Specific examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of these initiators added is preferably 0.01 to 25 mol% based on the total amount of monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, and more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the viewpoint of production efficiency.

[0495] The polymerization initiator may be added to the monomer solution and then fed to the reaction vessel. Alternatively, an initiator solution may be prepared separately from the monomer solution and then fed to the reaction vessel independently. From the perspective of quality control, it is preferable to prepare the monomer solution and the initiator solution independently and then add them dropwise, since radicals generated from the initiator during the waiting time may cause the polymerization reaction to proceed, resulting in the formation of ultra-high molecular weight polymers. The acid labile group may be used as is after being introduced into the monomer, or may be protected or partially protected after polymerization. Furthermore, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol may be used in combination to adjust the molecular weight. In this case, the amount of the chain transfer agent added is preferably 0.01 to 20 mol % of the total amount of monomers to be polymerized.

[0496] In the case of a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group, such as an ethoxyethoxy group, which is easily deprotected by an acid, during polymerization, and then deprotected with a weak acid and water after polymerization. Alternatively, the hydroxy group may be substituted with an acetyl group, a formyl group, a pivaloyl group, or the like, and then subjected to alkaline hydrolysis after polymerization.

[0497] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers may be polymerized by heating in an organic solvent with the addition of a radical polymerization initiator. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene may be used, and after polymerization, the acetoxy group may be deprotected by alkaline hydrolysis to form polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0498] Specific examples of the base that can be used in alkaline hydrolysis include aqueous ammonia, triethylamine, etc. The reaction temperature is preferably −20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0499] The amount of each monomer in the monomer solution may be appropriately set so as to achieve the preferred content ratio of the repeating units described above.

[0500] The polymer obtained by the above-described production method may be a reaction solution obtained by a polymerization reaction as a final product, or a powder obtained through a purification step such as a reprecipitation method in which a polymerization solution is added to a poor solvent to obtain a powder, and the resulting powder may be handled as a final product. However, from the viewpoint of work efficiency and quality stability, it is preferable to handle a polymer solution obtained by dissolving the powder obtained through the purification step in a solvent as a final product.

[0501] Specific examples of the solvent used in this case include ketones such as cyclohexanone and methyl-2-n-pentyl ketone, as described in paragraphs

[0144] to

[0145] of JP-A No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; 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 mono tert-butyl ether acetate; lactones such as GBL; alcohols such as diacetone alcohol (DAA); high-boiling alcohol solvents such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol; and mixed solvents thereof.

[0502] The concentration of the polymer in the polymer solution is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0503] The reaction solution and polymer solution are preferably filtered through a filter, which is effective in stabilizing quality by removing foreign matter and gels that may cause defects.

[0504] Examples of filter materials used in the filter filtration include fluorocarbon, cellulose, nylon, polyester, and hydrocarbon-based materials. However, in the filtration process for chemically amplified resist compositions, filters made of fluorocarbons, such as Teflon (registered trademark), hydrocarbons such as polyethylene and polypropylene, or nylon are preferred. The pore size of the filter can be selected appropriately depending on the desired cleanliness, but is preferably 100 nm or less, more preferably 20 nm or less. These filters may be used alone or in combination. The filtration method may involve passing the solution through the filter only once, but it is more preferable to circulate the solution and filter it multiple times. The filtration process can be performed in any order and any number of times during the polymer production process. However, it is preferable to filter the reaction solution after the polymerization reaction, the polymer solution, or both.

[0505] [Chemically amplified resist composition] [(A) Base polymer] The chemically amplified resist composition of the present invention contains, as component (A), a base polymer containing the above-mentioned polymer.

[0506] The polymers may be used singly or in combination of two or more with different composition ratios, Mw, and / or Mw / Mn. In addition to the polymers described above, the base polymer (A) may also contain a hydrogenated ring-opening metathesis polymer, and those described in JP-A-2003-66612 can be used.

[0507] [(B) Organic solvent] The chemically amplified resist composition of the present invention may contain an organic solvent as component (B). There are no particular limitations on the organic solvent (B) as long as it is capable of dissolving the components described above and below. Specific examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ketoalcohols such as 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 mono-tert-butyl ether acetate; lactones such as GBL, and mixed solvents thereof.

[0508] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixed solvents thereof are preferred, as they have particularly excellent solubility for the base polymer of component (A).

[0509] In the chemically amplified resist composition of the present invention, the content of (B) organic solvent is preferably 200 to 5000 parts by mass, more preferably 400 to 3500 parts by mass, relative to 80 parts by mass of (A) base polymer. (B) Organic solvent may be used singly or in combination of two or more types.

[0510] [(C) Quencher] The chemically amplified resist composition of the present invention may contain a quencher as component (C). In the present invention, the quencher is a material that traps the acid generated by the photoacid generator in the chemically amplified resist composition, thereby preventing it from diffusing to unexposed areas and forming a desired pattern.

[0511] Specific examples of the (C) quencher include onium salts represented by the following formula (1) or (2). [ka]

[0512] In formula (1), R q1 represents a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group. q2 is a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom.

[0513] R q1 Specific examples of the hydrocarbyl group having 1 to 40 carbon atoms represented by the formula (I) include alkyl groups having 1 to 40 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as a decyl group or an adamantyl group; and aryl groups having 6 to 40 carbon atoms, such as a phenyl group, a naphthyl group or an anthracenyl group. Some or all of the hydrogen atoms in the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms or halogen atoms, and some of the -CH2- groups in the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms or nitrogen atoms, so that the hydrocarbyl groups may contain hydroxy groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0514] R q2 Specific examples of the hydrocarbyl group represented by R q1 In addition to the substituents exemplified as specific examples, examples include fluorinated saturated hydrocarbyl groups such as trifluoromethyl group and trifluoroethyl group, and fluorinated aryl groups such as pentafluorophenyl group and 4-trifluoromethylphenyl group.

[0515] Specific examples of the anion of the onium salt represented by formula (1) include, but are not limited to, those shown below. [ka]

[0516] [ka]

[0517] [ka]

[0518] [ka]

[0519] [ka]

[0520] Specific examples of the anion of the onium salt represented by formula (2) include, but are not limited to, those shown below. [ka]

[0521] [ka]

[0522] [ka]

[0523] [ka]

[0524] [ka]

[0525] In equations (1) and (2), Mq +is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation, or an ammonium cation. Specific examples of the sulfonium cation include those exemplified as sulfonium cations of the sulfonium salt-type monomer represented by formula (a), those described in paragraphs

[0102] to

[0125] of JP-A No. 2024-3744, those described in paragraphs

[0070] to

[0085] of JP-A No. 2023-169812, and those represented by formula (d3), but are not limited thereto. Specific examples of the iodonium cation include those described in paragraph

[0181] of JP-A No. 2024-000259, but are not limited thereto. The ammonium cation is preferably one represented by the following formula (am-1): [ka]

[0526] In formula (am-1), R q11 ~R q14 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. ct6 and R ct7 However, they may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded. Specific examples of the hydrocarbyl group include R 2 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0527] Specific examples of the ammonium cation represented by formula (am-1) include, but are not limited to, those shown below. [ka]

[0528] Specific examples of the onium salt represented by formula (1) or (2) include any combination of the anions and cations described above. These onium salts can be easily prepared by ion exchange reactions using known organic chemical methods. For details on ion exchange reactions, see, for example, JP 2007-145797 A.

[0529] The onium salt represented by formula (1) or (2) functions as a quencher in the chemically amplified resist composition of the present invention. This is because the counter anion of each onium salt is the conjugate base of a weak acid. The term "weak acid" as used herein refers to an acidity that is insufficient to deprotect the acid labile group in the acid labile group-containing unit used in the base polymer. The onium salt represented by formula (1) or (2) functions as a quencher when used in combination with an onium salt-type photoacid generator having a counter anion that is the conjugate base of a strong acid, such as a sulfonic acid fluorinated at the α-position. Specifically, when an onium salt that generates a strong acid, such as a sulfonic acid fluorinated at the α-position, is mixed with an onium salt that generates a weak acid, such as a non-fluorinated sulfonic acid or carboxylic acid, the strong acid generated from the photoacid generator upon irradiation with high-energy radiation collides with an onium salt having an unreacted weak acid anion, releasing the weak acid through salt exchange and generating an onium salt having a strong acid anion. In this process, the strong acid is exchanged for a weak acid with a lower catalytic activity, and the acid appears to be deactivated, allowing for control of acid diffusion.

[0530] Furthermore, as the (C) quencher, onium salts having a sulfonium cation and a phenoxide anion moiety in the same molecule as described in Japanese Patent No. 6848776, onium salts having a sulfonium cation and a carboxylate anion moiety in the same molecule as described in Japanese Patent No. 6583136 and JP-A-2020-200311, and onium salts having an iodonium cation and a carboxylate anion moiety in the same molecule as described in Japanese Patent No. 6274755 can also be used.

[0531] Here, when the photoacid generator that generates a strong acid is an onium salt, the strong acid generated by irradiation with high-energy rays can be exchanged for a weak acid as described above, but on the other hand, it is thought that the weak acid generated by irradiation with high-energy rays collides with the unreacted onium salt that generates the strong acid, making it difficult to carry out salt exchange. This is due to the phenomenon that the onium cation is more likely to form an ion pair with the anion of the strong acid.

[0532] When the chemically amplified resist composition of the present invention contains an onium salt represented by formula (1) or (2) as the quencher (C), the content thereof is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, relative to 80 parts by mass of the base polymer (A). A content of the onium salt quencher of component (C) within the above range is preferred because it provides good resolution and does not significantly reduce sensitivity. The onium salt represented by formula (1) or (2) may be used alone or in combination of two or more.

[0533] The chemically amplified resist composition of the present invention may contain a nitrogen-containing compound as a quencher (C). Specific examples of the nitrogen-containing compound (C) include primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond. Further examples include compounds in which a primary or secondary amine is protected with a carbamate group, as described in JP 3790649 A.

[0534] Alternatively, a sulfonate sulfonium salt having a nitrogen-containing substituent may be used as the nitrogen-containing compound. Such a compound functions as a quencher in the unexposed area and loses its quenching ability in the exposed area by neutralizing with the acid generated by the compound itself, functioning as a so-called photodegradable base. The use of a photodegradable base can further enhance the contrast between the exposed and unexposed areas. For example, JP-A Nos. 2009-109595 and 2012-46501 can be used as references for the photodegradable base.

[0535] When the chemically amplified resist composition of the present invention contains a nitrogen-containing compound as a quencher (C), the content thereof is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass, relative to 80 parts by mass of the base polymer (A). The nitrogen-containing compound may be used alone or in combination of two or more types.

[0536] [(D) Acid generator] The chemically amplified resist composition of the present invention may contain an acid generator, provided that the effects of the present invention are not impaired. Examples of the acid generator include compounds (photoacid generators) that generate acid in response to actinic rays or radiation. The photoacid generator is not particularly limited as long as it generates an acid upon exposure to high-energy rays, but preferred are those that generate sulfonic acid, imide acid, or methide acid. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators. Specific examples of acid generators include those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A.

[0537] Furthermore, as the photoacid generator, a sulfonium salt represented by the following formula (3-1) or an iodonium salt represented by the following formula (3-2) can also be suitably used. [ka]

[0538] In formulas (3-1) and (3-2), R 101 ~R 105 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. Specific examples of the halogen atom and hydrocarbyl group include R 2Examples of the halogen atom and hydrocarbyl group include those exemplified above. In addition, some or all of the hydrogen atoms in the hydrocarbyl 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 some of the -CH2- in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, so that the hydrocarbyl group may contain a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. In addition, R 101 and R 102 However, they may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Specific examples of the ring formed in this case include S + Examples of the ring that can be formed when two of the three substituents bonded to the group are bonded to each other together with the sulfur atom to which they are bonded include the same as those exemplified above.

[0539] Specific examples of the sulfonium salt cation represented by formula (3-1) include, but are not limited to, those exemplified as sulfonium cations of sulfonium salt monomers represented by formula (a), those described in paragraphs

[0102] to

[0125] of JP-A No. 2024-3744, those described in paragraphs

[0070] to

[0085] of JP-A No. 2023-169812, and those represented by formula (d3). Specific examples of the iodonium salt cation represented by formula (3-2) include, but are not limited to, those described in paragraph

[0181] of JP-A No. 2024-000259.

[0540] In formulas (3-1) and (3-2), Xa - is an anion selected from the following formulae (3A) to (3D). [ka]

[0541] In formula (3A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A') described below. fa1 Examples include those similar to those exemplified in the explanation of .

[0542] The anion represented by formula (3A) is preferably one represented by the following formula (3A'). [ka]

[0543] In formula (3A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0544] In formula (3A'), R fa1 is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, or the like, and more preferably an oxygen atom. From the viewpoint of obtaining high resolution in the formation of a fine pattern, the hydrocarbyl group is particularly preferably one having 6 to 30 carbon atoms.

[0545] R fa1The hydrocarbyl group having 1 to 38 carbon atoms and represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosyl groups; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, and norbornyl. Examples of such groups include saturated cyclic hydrocarbyl groups having 3 to 38 carbon atoms, such as an allyl group, a norbornylmethyl group, a tricyclodecyl group, a tetracyclododecyl group, a tetracyclododecylmethyl group, and a dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 38 carbon atoms, such as an allyl group and a 3-cyclohexenyl group; aryl groups having 6 to 38 carbon atoms, such as a phenyl group, a 1-naphthyl group, and a 2-naphthyl group; aralkyl groups having 7 to 38 carbon atoms, such as a benzyl group and a diphenylmethyl group; and groups obtained by combining these groups.

[0546] In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, or some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, resulting in the hydrocarbyl group containing a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. The heteroatom is preferably an oxygen atom. Specific examples of hydrocarbyl groups containing hetero atoms include tetrahydrofuryl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, and 3-oxocyclohexyl groups.

[0547] Synthesis of sulfonium salts containing anions represented by formula (3A') is described in detail in JP-A Nos. 2007-145797, 2008-106045, 2009-7327, and 2009-258695. Sulfonium salts described in JP-A Nos. 2010-215608, 2012-41320, 2012-106986, and 2012-153644 are also suitable.

[0548] Specific examples of the anion represented by formula (3A) include, but are not limited to, those shown below: In the following formula, Ac is an acetyl group. [ka]

[0549] [ka]

[0550] [ka]

[0551] [ka]

[0552] In formula (3B), R fb1 and R fb2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). fa1 Examples of the hydrocarbyl group represented by R include the same as those exemplified above. fb1 and R fb2is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 means that the groups to which they are bonded (-CF2-SO2-N - -SO2-CF2-) together to form a ring, in which case, R fb1 and R fb2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0553] In formula (3C), R fc1 , R fc2 and R fc3 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). fa1 Examples of the hydrocarbyl group represented by R include the same as those exemplified above. fc1 , R fc2 and R fc3 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 are groups that are bonded together and bond to each other (-CF2-SO2-C - -SO2-CF2-) together to form a ring, in which case, R fc1 and R fc2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0554] In formula (3D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). fa1 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0555] The synthesis of sulfonium salts containing anions represented by formula (3D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

[0556] Specific examples of the anion represented by formula (3D) include, but are not limited to, those shown below. [ka]

[0557] [ka]

[0558] Although the photoacid generator containing the anion represented by formula (3D) does not have a fluorine atom at the α-position of the sulfo group, it has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave the acid labile groups in the base polymer, making it suitable for use as a photoacid generator.

[0559] As the photoacid generator, a compound represented by the following formula (4) can also be suitably used. [ka]

[0560] In formula (4), R 201 and R 202 R are each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 201 , R 202 and R 203 Any two of these may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, specific examples of the ring include S +Examples of the ring that can be formed when two of the three substituents bonded to the group are bonded to each other together with the sulfur atom to which they are bonded include the same as those exemplified above.

[0561] R 201 and R 202 The hydrocarbyl group having 1 to 30 carbon atoms represented by the formula (I) 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, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, an oxanorbornyl group, and a tricyclo[5.2.1.0] 2,6cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as a decyl group and an adamantyl group; aryl groups having 6 to 30 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, a tert-butylnaphthyl group and an anthracenyl group; and groups obtained by combining these groups. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0562] R 203The hydrocarbylene group having 1 to 30 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups having 1 to 30 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, and heptadecane-1,17-diyl group; cyclopentanediyl group, cyclohexene-1,18-diyl group, and the like. Examples of the alkylene groups include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as xanediyl, norbornanediyl, and 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, and tert-butylnaphthylene; and groups obtained by combining these groups. In addition, some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH- groups of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the hydrocarbylene group containing a hydroxy 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 ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. As the heteroatom, an oxygen atom is preferred.

[0563] In formula (4), L1 is a single bond, an ether bond, or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 203 Examples of the hydrocarbylene group represented by the formula (I) include the same as those exemplified above.

[0564] 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, provided that X a , X b , X c and X d At least one of the groups is a fluorine atom or a trifluoromethyl group.

[0565] In formula (4), k is 0, 1, 2 or 3.

[0566] The photoacid generator represented by formula (4) is preferably one represented by the following formula (4'). [ka]

[0567] In formula (4'), L 1 is the same as above. X e is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). fa1 Examples of the hydrocarbyl group include the same as those exemplified above. x and y are each independently 0, 1, 2, 3, 4, or 5. z is 0, 1, 2, 3, or 4.

[0568] Specific examples of the photoacid generator represented by formula (4) include the same compounds as those exemplified as the photoacid generator represented by formula (2) in JP-A-2017-26980.

[0569] Among the photoacid generators, those containing an anion represented by formula (3A') or (3D) are particularly preferred because of their small acid diffusion and excellent solubility in solvents. Also, those represented by formula (4') are particularly preferred because of their extremely small acid diffusion.

[0570] As other acid generators, sulfonium salts and iodonium salts containing an anion having an aromatic ring substituted with an iodine atom, represented by the following formula (5-1) or (5-2), can also be used. [ka]

[0571] In formulas (5-1) and (5-2), p is 1, 2, or 3. q is 1, 2, 3, 4, or 5. r is 0, 1, 2, or 3, provided that 1≦q+r≦5. q is preferably 1, 2, or 3, and more preferably 2 or 3. r is preferably 0, 1, or 2.

[0572] In formulas (5-1) and (5-2), L 11 is a single bond, an ether bond, an ester bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0573] In formulas (5-1) and (5-2), L 12 represents a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and represents a (p+1)-valent linking group having 1 to 20 carbon atoms when p is 2 or 3, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0574] In formulas (5-1) and (5-2), R 401is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms or a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond, or 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-OR 401D R 401A and R 401B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 401C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 401D is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 may be the same or different from each other.

[0575] Of these, R 401Examples of the hydroxyl group include -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-OR 401D fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, etc. are preferred.

[0576] In formulas (5-1) and (5-2), Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of them is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine to form a carbonyl group. 3 and Rf 4 are preferably both fluorine atoms.

[0577] In formulas (5-1) and (5-2), R 402 ~R 406 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 2 Examples of the hydrocarbyl group include the same as those exemplified above. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone ring, a sulfo group, or a sulfonium salt-containing group, and some of the -CH2- groups of the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate ester bond. 402 and R 403 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, specific examples of the ring include S + Examples of the ring that can be formed when two of the three substituents bonded to the group are bonded to each other together with the sulfur atom to which they are bonded include the same as those exemplified above.

[0578] Specific examples of the cation of the sulfonium salt represented by formula (5-1) include those described in paragraphs

[0102] to

[0125] of JP-A No. 2024-3744, those described in paragraphs

[0070] to

[0085] of JP-A No. 2023-169812, and those represented by formula (d3). Specific examples of the cation of the iodonium salt represented by formula (5-2) include those described in paragraph

[0181] of JP-A No. 2024-000259.

[0579] Specific examples of the anion of the onium salt represented by formula (5-1) or (5-2) include, but are not limited to, those shown below. [ka]

[0580] [ka]

[0581] [ka]

[0582] [ka]

[0583] [ka]

[0584] [ka]

[0585] [ka]

[0586]

change

[0587]

change

[0588]

change

[0589]

change

[0590]

change

[0591]

change

[0592]

change

[0593]

change

[0594]

change

[0595]

change

[0596]

change

[0597] [ka]

[0598] [ka]

[0599] [ka]

[0600] [ka]

[0601] When the chemically amplified resist composition of the present invention contains an acid generator (D), the content thereof is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 20 parts by mass, per 80 parts by mass of the base polymer (A). When the amount of the acid generator (D) added is within the above range, the resolution is good and there is no risk of problems with foreign matter occurring after development of the resist film or during stripping, which is preferable. The acid generator (D) may be used alone or in combination of two or more types.

[0602] [(E) Surfactant] The chemically amplified resist composition of the present invention may further comprise a surfactant as component (E). The surfactant (E) is preferably a surfactant that is insoluble or slightly soluble in water but soluble in an alkaline developer, or a surfactant that is insoluble or slightly soluble in both water and an alkaline developer. Examples of such surfactants include those described in JP-A-2010-215608 and JP-A-2011-16746.

[0603] Among the surfactants described in the above publications, preferred surfactants that are insoluble or slightly soluble in water and alkaline developers include FC-4430 (manufactured by 3M), Surflon (registered trademark) S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Olfine (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and oxetane ring-opening polymers represented by the following formula (surf-1): [ka]

[0604] Here, R, Rf, A, B, C, m, and n apply only to formula (surf-1), regardless of the above descriptions. R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. Examples of the divalent aliphatic group include an ethylene group, a 1,4-butylene group, a 1,2-propylene group, a 2,2-dimethyl-1,3-propylene group, and a 1,5-pentylene group, and examples of the trivalent or tetravalent aliphatic group include the following: [ka] (In the formula, the dashed lines represent bonds and are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.)

[0605] Among these, a 1,4-butylene group, a 2,2-dimethyl-1,3-propylene group, and the like are preferred.

[0606] Rf is a trifluoromethyl group or a pentafluoroethyl group, preferably a trifluoromethyl group. m is an integer of 0 to 3, n is an integer of 1 to 4, and the sum of n and m is the valence of R, which is an integer of 2 to 4. A is 1. B is an integer of 2 to 25, preferably an integer of 4 to 20. C is an integer of 0 to 10, preferably 0 or 1. The order of the structural units in formula (surf-1) is not specified, and they may be bonded in blocks or randomly. The production of surfactants based on partially fluorinated oxetane ring-opening polymers is described in detail in the specification of U.S. Pat. No. 5,650,483, etc.

[0607] Surfactants that are insoluble or slightly soluble in water but soluble in alkaline developers have the function of reducing water penetration and leaching by orienting themselves on the surface of the resist film when a resist protective film is not used in ArF immersion lithography. Therefore, they are useful for suppressing the elution of water-soluble components from the resist film and reducing damage to the exposure equipment. They are also useful because they become soluble during alkaline aqueous development after exposure or post-exposure bake (PEB), making them less likely to become contaminants that cause defects. Such surfactants are insoluble or slightly soluble in water but soluble in alkaline developers. They are polymeric surfactants, also known as hydrophobic resins, and are particularly preferred because they have high water repellency and improve water slippage.

[0608] Specific examples of such polymer surfactants include those containing at least one repeating unit selected from the repeating units represented by the following formulas (6A) to (6E). [ka]

[0609] In formulas (6A) to (6E), R B is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 is -CH2-, -CH2CH2-, -O- or two -H groups separated from each other. s1are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. s2 R is a single bond or a linear or branched hydrocarbylene group having 1 to 5 carbon atoms. s3 R are each independently a hydrogen atom, a hydrocarbyl group or a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group. s3 When R is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bonds. s4 is a hydrocarbon group or a fluorinated hydrocarbon group having 1 to 20 carbon atoms and a valence of (u+1). u is 1, 2, or 3. R s5 are each independently a hydrogen atom or -C(=O)-OR sa R sa is a fluorinated hydrocarbyl group having 1 to 20 carbon atoms. s6 is a hydrocarbyl group or a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, and an ether bond or a carbonyl group may be present between the carbon-carbon bonds.

[0610] R s1 The hydrocarbyl group having 1 to 10 carbon atoms represented by the formula (I) is preferably a saturated hydrocarbyl group, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl. Of these, those having 1 to 6 carbon atoms are preferred.

[0611] R s2 The hydrocarbylene group represented by the formula (I) is preferably a saturated hydrocarbylene group, which may be linear, branched, or cyclic. Specific examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group, and a pentylene group.

[0612] R s3 or R s6 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include saturated hydrocarbyl groups and aliphatic unsaturated hydrocarbyl groups such as alkenyl groups and alkynyl groups, with saturated hydrocarbyl groups being preferred. Specific examples of the saturated hydrocarbyl group include R s1 In addition to the examples of the hydrocarbyl group represented by the formula (R), examples include an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group. s3 or R s6 Specific examples of the fluorinated hydrocarbyl group represented by the formula (I) include groups in which some or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbyl group have been substituted with fluorine atoms. As mentioned above, an ether bond or a carbonyl group may be present between these carbon-carbon bonds.

[0613] R s3 Specific examples of the acid labile group represented by the formula (AL-3) to (AL-5) include the groups represented by the formulas (AL-3) to (AL-5) above, trialkylsilyl groups in which each alkyl group has 1 to 6 carbon atoms, and oxo group-containing alkyl groups having 4 to 20 carbon atoms.

[0614] R s4 The (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include groups obtained by further eliminating u hydrogen atoms from the aforementioned hydrocarbyl group or fluorinated hydrocarbyl group.

[0615] R saThe fluorinated hydrocarbyl group represented by the formula (I) is preferably saturated, and may be linear, branched, or cyclic. Specific examples thereof include those in which some or all of the hydrogen atoms of the hydrocarbyl groups have been substituted with fluorine atoms, and specific examples thereof include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoro-1-propyl group, a 3,3,3-trifluoro-2-propyl group, a 2,2,3,3-tetrafluoropropyl group, a 1,1,1,3,3,3-hexafluoroisopropyl group, a 2,2,3,3,4,4,4-heptafluorobutyl group, a 2,2,3,3,4,4,5,5-octafluoropentyl group, a 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl group, a 2-(perfluorobutyl)ethyl group, a 2-(perfluorohexyl)ethyl group, a 2-(perfluorooctyl)ethyl group, and a 2-(perfluorodecyl)ethyl group.

[0616] Specific examples of the repeating unit represented by any one of formulas (6A) to (6E) include, but are not limited to, the following: B is the same as above. [ka]

[0617] [ka]

[0618] [ka]

[0619] [ka]

[0620] [ka]

[0621] The polymer surfactant may further contain other repeating units in addition to the repeating units represented by formulae (6A) to (6E). Specific examples of other repeating units include repeating units obtained from methacrylic acid, α-trifluoromethylacrylic acid derivatives, etc. In the polymer surfactant, the content of the repeating units represented by formulae (6A) to (6E) in all repeating units is preferably 20 mol % or more, more preferably 60 mol % or more, and even more preferably 100 mol %.

[0622] The Mw of the polymer surfactant is preferably from 1,000 to 500,000, and more preferably from 3,000 to 100,000. The Mw / Mn is preferably from 1.0 to 2.0, and more preferably from 1.0 to 1.6.

[0623] The polymeric surfactant can be synthesized by heating a monomer containing an unsaturated bond that provides the repeating units represented by formulas (6A) to (6E) and, if necessary, other repeating units, in an organic solvent with the addition of a radical initiator to polymerize the monomer. Specific examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, and dioxane. Specific examples of polymerization initiators include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. The acid labile group introduced into the monomer may be used as is, or may be protected or partially protected after polymerization.

[0624] When synthesizing the polymer surfactant, a known chain transfer agent such as dodecyl mercaptan or 2-mercaptoethanol may be used to adjust the molecular weight. In this case, the amount of the chain transfer agent added is preferably 0.01 to 10 mol % based on the total number of moles of the monomers to be polymerized.

[0625] When the chemically amplified resist composition of the present invention contains a surfactant (E), the content thereof is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass, per 80 parts by mass of the base polymer (A). When the surfactant (E) content is 0.1 part by mass or more, the receding contact angle between the resist film surface and water is sufficiently improved, while when the surfactant content is 50 parts by mass or less, the dissolution rate of the resist film surface in the developer is low, and the height of the formed fine pattern is sufficiently maintained. The surfactant (E) may be used alone or in combination of two or more types.

[0626] [(F) Dissolution inhibitor] The chemically amplified resist composition of the present invention may further comprise a dissolution inhibitor as component (F). When the chemically amplified resist composition of the present invention is a positive-working composition, the incorporation of a dissolution inhibitor can further increase the difference in dissolution rate between exposed and unexposed areas, thereby further improving resolution.

[0627] Specific examples of the dissolution inhibitor include compounds having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800, containing two or more phenolic hydroxy groups in the molecule, in which the hydrogen atoms of the phenolic hydroxy groups have been substituted with acid labile groups in an overall ratio of 0 to 100 mol %, and compounds containing carboxy groups in the molecule, in which the hydrogen atoms of the carboxy groups have been substituted with acid labile groups in an overall ratio of 50 to 100 mol %. Specific examples include compounds in which the hydrogen atoms of the hydroxyl groups or carboxyl groups of bisphenol A, trisphenol, phenolphthalein, cresol novolak, naphthalenecarboxylic acid, adamantanecarboxylic acid, or cholic acid have been substituted with acid labile groups, such as those described in paragraphs

[0155] to

[0178] of JP 2008-122932 A.

[0628] When the chemically amplified resist composition of the present invention contains a dissolution inhibitor (F), the content thereof is preferably 0 to 50 parts by mass, and more preferably 5 to 40 parts by mass, relative to 80 parts by mass of the base polymer (A). The dissolution inhibitor (F) may be used alone or in combination of two or more types.

[0629] [(G) Other ingredients] The chemically amplified resist composition of the present invention may contain, as (G) other components, a compound that decomposes in the presence of acid to generate acid (acid amplifying compound), an organic acid derivative, a fluorine-substituted alcohol, a water repellency improver, etc. Examples of the acid amplifying compound include the compounds described in JP-A-2009-269953 and JP-A-2010-215608. When the acid amplifying compound is contained, its content is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass, per 80 parts by mass of the (A) base polymer. If the content is too high, it may be difficult to control acid diffusion, resulting in degradation of resolution and pattern shape. Examples of the organic acid derivative and fluorine-substituted alcohol include the compounds described in JP-A-2009-269953 and JP-A-2010-215608.

[0630] The water repellency improver can be used in immersion lithography without a topcoat. Preferred examples of the water repellency improver include polymers containing fluorinated alkyl groups and polymers containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue with a specific structure, with those exemplified in JP-A Nos. 2007-297590 and 2008-111103 being more preferred. The water repellency improver must be soluble in an alkaline developer or an organic solvent developer. The water repellency improver having the specific 1,1,1,3,3,3-hexafluoro-2-propanol residue described above has good solubility in the developer. As a water repellency improver, polymers containing repeating units containing an amino group or an amine salt are highly effective in preventing the evaporation of acid during PEB and preventing poor opening of the hole pattern after development. When the chemically amplified resist composition of the present invention contains the water repellency improver, the content thereof is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the (A) base polymer.

[0631] [Pattern formation method] When the chemically amplified resist composition of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied. For example, a pattern formation method can include a method comprising the steps of forming a resist film on a substrate using the above-mentioned chemically amplified resist composition, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer.

[0632] First, the chemically amplified resist composition of the present invention is applied to a substrate for integrated circuit production (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective coating, etc.) or a substrate for mask circuit production (Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., to a coating thickness of 0.01 to 2.0 μm. This is then prebaked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0633] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, EB, EUV radiation with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When ultraviolet radiation, far ultraviolet radiation, EUV radiation, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation are used as the high-energy radiation, the exposure dose is preferably 1 to 200 mJ / cm, either directly or using a mask for forming a desired pattern. 2 approximately, more preferably 10 to 100 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 100 μC / cm 2 approximately, more preferably 0.5 to 50 μC / cm 2The resist composition of the present invention is particularly suitable for fine patterning using high-energy rays such as ArF excimer laser light with a wavelength of 193 nm, KrF excimer laser light with a wavelength of 248 nm, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, gamma rays, or synchrotron radiation.

[0634] After the exposure, PEB may be performed 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.

[0635] After exposure or PEB, the substrate is developed using a developer such as an aqueous alkaline solution of 0.1 to 10 mass %, preferably 2 to 5 mass %, of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or the like, for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by a conventional method such as dipping, puddling, or spraying. The irradiated portions dissolve in the developer, while the unexposed portions do not, forming the desired positive pattern on the substrate.

[0636] A negative pattern can also be obtained by using an organic solvent developer instead of the alkaline aqueous solution. Specific examples of the developer used in this case include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, and ethyl crotonate. Examples of organic solvents include methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and 2-phenylethyl acetate. These organic solvents may be used alone or in combination of two or more.

[0637] After the development is completed, rinsing may be performed. As a rinsing liquid, a solvent that is miscible with the developer but does not dissolve the resist film is preferred. As such a solvent, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes having 6 to 12 carbon atoms, and aromatic solvents are preferably used.

[0638] Specific examples of the alcohol having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, and 3-hexanol. Examples of the alcohol include 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol.

[0639] Specific examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, and di-n-hexyl ether.

[0640] 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, etc. Specific examples of the alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Specific examples of the alkynes having 6 to 12 carbon atoms include hexyne, heptine, octyne, etc.

[0641] Specific examples of the aromatic solvent include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0642] Rinsing can reduce the occurrence of resist pattern collapse and defects. Rinsing is not always necessary, and not performing rinsing can reduce the amount of solvent used.

[0643] The developed hole or trench pattern can also be shrunk using thermal flow, RELACS, or DSA. A shrink agent is applied to the hole pattern, and the diffusion of an acid catalyst from the resist film during baking causes crosslinking of the shrink agent on the surface of the resist film, resulting in adhesion of the shrink agent 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. Excess shrink agent is removed, and the hole pattern is shrunk. [Example]

[0644] The present invention will be specifically explained below by showing synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. The apparatuses used are as follows. MALDI TOF-MS: JEOL S3000

[0645] [1] Synthesis of sulfonium salt monomers [Example 1-1] Synthesis of sulfonium salt monomer a-1 [ka]

[0646] (1) Synthesis of intermediate In-1 A Grignard reagent was prepared from magnesium (4.5 g), THF (100 g), and intermediate In-1 (51.0 g) under a nitrogen atmosphere. The reaction system was cooled to below 10°C, and a solution consisting of diphenyl sulfoxide (12.1 g) and methylene chloride (50 g) was added. After the addition, chlorotrimethylsilane (19.6 g) was added dropwise while maintaining the temperature of the reaction system below 20°C. After the addition, the reaction system was aged for 2 hours at a temperature below 20°C. After aging, the reaction system was cooled, and an aqueous solution consisting of ammonium chloride (15 g), 20% by weight hydrochloric acid (15 g), and water (100 g) was added dropwise to quench the reaction. Methanol (50 g) and diisopropyl ether (200 g) were then added, and the aqueous layer was separated and collected. The separated aqueous layer was then washed twice with hexane (200 g). Methylene chloride (100 g) was added to the washed aqueous layer to extract the target product, followed by a standard aqueous work-up and distillation of the solvent to obtain 24.5 g of intermediate In-2 as a colorless oil (yield 87%).

[0647] (2) Synthesis of onium salt monomer a-1 Under a nitrogen atmosphere, intermediate In-1 (24.5 g), intermediate In-2 (22.0 g), methylene chloride (150 g), and water (70 g) were charged and stirred at room temperature for 30 minutes. The organic layer was separated, washed with water, and then concentrated under reduced pressure. The residue was washed with diisopropyl ether and concentrated to obtain 33.8 g of PAG-1 as an oil (yield 94%).

[0648] The results of TOF-MS of the sulfonium salt type monomer a-1 are shown below. MALDI TOF-MS: POSITIVE M + 389 (C 18 H 14 F5S2 + equivalent) NEGATIVE M - 555(C 15 H9I2O5S - equivalent)

[0649] [Examples 1-2 to 1-7] Synthesis of sulfonium salt monomers a-2 to a-7 Using the corresponding raw materials and known organic synthesis reactions, sulfonium salt-type monomers a-2 to a-7 represented by the following formulas were synthesized. [ka]

[0650] [Comparative Examples 1-1 to 1-5] Synthesis of comparative onium salt monomers ca-1 to ca-5 Comparative onium salt-type monomers ca-1 to ca-5 represented by the following formulae were synthesized using the corresponding raw materials and known organic synthesis reactions. [ka]

[0651] [2] Synthesis of base polymer Of the monomers used in the synthesis of the base polymer, those other than the monomers a-1 to a-7 and the comparative monomers ca-1 to ca-5 are as follows. [ka]

[0652] [ka]

[0653] [ka]

[0654] [ka]

[0655] [ka]

[0656] [Example 2-1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, a flask was charged with 13.7 g of monomer a-1, 30.0 g of monomer b1-1, 9.7 g of monomer c-1, 46.8 g of monomer d-1, 3.09 g of V-601 (Fujifilm Wako Pure Chemical Industries, Ltd.), and 139 g of MEK to prepare a monomer-polymerization initiator solution. 46 g of MEK was charged to a separate flask under a nitrogen atmosphere and heated to 80°C with stirring. The monomer-polymerization initiator solution was then added dropwise over 4 hours. After the addition was complete, stirring was continued for 2 hours while maintaining the temperature of the polymerization solution at 80°C, and then the mixture was cooled to room temperature. The resulting polymerization solution was added dropwise to 3,000 g of vigorously stirred hexane, and the precipitated polymer was filtered off. The resulting polymer was washed twice with 600 g of hexane and then vacuum-dried at 50°C for 20 hours to obtain polymer P-1 as a white powder (yield: 96.1 g, 96%). Polymer P-1 had an Mw of 10,300 and an Mw / Mn of 1.61. Note that Mw was measured in terms of polystyrene by GPC using DMF as a solvent. [ka]

[0657] [Examples 2-2 to 2-50, Comparative Examples 2-1 to 2-38] Synthesis of Polymers P-2 to P-50 and Comparative Polymers CP-1 to CP-38 The polymers shown in Tables 1 to 3 were produced in the same manner as in Synthesis Example 2-1, except that the types and blending ratios of the monomers were changed.

[0658] [Table 1]

[0659] [Table 2]

[0660] [Table 3]

[0661] [3] Preparation of chemically amplified resist composition [Examples 3-1 to 3-53, Comparative Examples 3-1 to 3-40] Predetermined components selected from the base polymers of the present invention (P-1 to P-50), comparative base polymers (CP-1 to CP-38), acid generators (PAG-1, PAG-2), and quenchers (SQ-1, AQ-1) were dissolved in a solvent containing 0.01 mass% of FC-4430 (manufactured by 3M) as a surfactant in the compositions shown in Tables 4 to 6 below to prepare solutions. The solutions were then filtered through a 0.2 μm Teflon (registered trademark) filter to prepare chemically amplified resist compositions (R-1 to R-53, CR-1 to CR-40).

[0662] [Table 4]

[0663] [Table 5]

[0664] [Table 6]

[0665] In Tables 4 to 6, the solvents, quenchers (SQ-1, AQ-1) and acid generators (PAG-1, PAG-2) are as follows. Solvent: PGMEA (propylene glycol monomethyl ether acetate) EL (Ethyl lactate) DAA (diacetone alcohol)

[0666] Quencher: SQ-1, AQ-1 [ka]

[0667] Acid generator: PAG-1, PAG-2 [ka]

[0668] [4] EUV Lithography Evaluation (1) [Examples 4-1 to 4-53, Comparative Examples 4-1 to 4-40] Each chemically amplified resist composition (R-1 to R-53, CR-1 to CR-40) shown in Tables 4 to 6 was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. had been formed to a thickness of 20 nm, and the substrate was pre-baked at 100°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. The resist film was exposed to an LS pattern with an on-wafer dimension of 18 nm and a pitch of 36 nm using an ASML EUV scanner NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination) while varying the exposure dose and focus (exposure dose pitch: 1 mJ / cm). 2 After exposure, PEB was performed for 60 seconds at the temperatures shown in Tables 7 to 9. Thereafter, puddle development was performed with a 2.38 mass % TMAH aqueous solution for 30 seconds, followed by rinsing with a surfactant-containing rinse material and spin drying to obtain a positive pattern. The obtained LS pattern was observed with a critical dimension SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, and the sensitivity, EL, LWR, DOF, and collapse limit were evaluated according to the following methods. The results are shown in Tables 7 to 9.

[0669] [Sensitivity evaluation] The optimum exposure dose Eop (mJ / cm) to obtain an LS pattern with a line width of 18 nm and a pitch of 36 nm 2 The smaller this value, the higher the sensitivity.

[0670] [EL Evaluation] EL (unit: %) was calculated from the exposure amount formed within a range of ±10% (16.2 to 19.8 nm) of the 18 nm space width in the LS pattern using the following formula: The larger this value, the better the performance. EL(%)=(|E1-E2| / Eop)×100 E1: Optimal exposure dose for LS pattern with line width of 16.2 nm and pitch of 36 nm E2: Optimal exposure dose for LS pattern with line width of 19.8 nm and pitch of 36 nm Eop: Optimal exposure dose for LS pattern with line width of 18nm and pitch of 36nm

[0671] [LWR rating] The LS pattern obtained by irradiation with Eop was measured at 10 points along the line length, and the LWR was calculated as three times the standard deviation (σ) (3σ). The smaller this value, the less roughness and the more uniform the line width pattern obtained.

[0672] [DOF evaluation] For the evaluation of the depth of focus, the focus range formed within a range of ±10% (16.2 to 19.8 nm) of the 18 nm dimension of the LS pattern was determined. The larger this value, the wider the depth of focus.

[0673] [Line pattern collapse limit evaluation] The line dimension of the LS pattern at each exposure dose at the optimum focus was measured at 10 points in the longitudinal direction. The thinnest line dimension obtained without collapse was defined as the collapse limit dimension. The smaller this value, the better the collapse limit.

[0674] [Table 7]

[0675] [Table 8]

[0676] [Table 9]

[0677] The results shown in Tables 7 to 9 demonstrate that chemically amplified resist compositions using base polymers containing repeating units derived from onium salt-type monomers of the present invention have good sensitivity and excellent EL, LWR, and DOF. Furthermore, the collapse limit value was small, demonstrating resistance to pattern collapse even in fine pattern formation. Therefore, it was demonstrated that the chemically amplified resist composition of the present invention is suitable as a material for EUV lithography.

[0678] [5] EUV Lithography Evaluation (2) [Examples 5-1 to 5-53, Comparative Examples 5-1 to 5-40] Each chemically amplified resist composition (R-1 to R-53, CR-1 to CR-10) listed in Tables 4 to 6 was spin-coated onto a 20 nm thick silicon spin-on hard mask (SHB-A940, manufactured by Shin-Etsu Chemical Co., Ltd.) containing 43% silicon by weight. The resist was then pre-baked at 105°C for 60 seconds using a hot plate to produce a 50 nm thick resist film. The resist film was then exposed to light using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple-pole illumination, 46 nm pitch on the wafer, and a hole pattern mask with a +20% bias). The resist film was then subjected to PEB for 60 seconds using a hot plate at the temperatures listed in Tables 7 and 8, followed by development for 30 seconds in a 2.38% by weight aqueous TMAH solution to produce a 23 nm hole pattern. Using a Hitachi High-Technologies Corporation CD-SEM (CG6300), the exposure dose when a hole dimension of 23 nm was formed was measured and used as the sensitivity. The dimensions of 50 holes were also measured, and the standard deviation (σ) calculated from the results was tripled (3σ) to give the dimensional variation (CDU). The results are shown in Tables 10 to 12.

[0679] [Table 10]

[0680] [Table 11]

[0681] [Table 12]

[0682] The results shown in Tables 10 to 12 confirm that the chemically amplified resist composition of the present invention has good sensitivity and excellent CDU.

[0683] [6] Dry etching resistance evaluation [Examples 6-1 to 6-50, Comparative Examples 6-1 to 6-38] 2 g of each of the polymers shown in Tables 1 and 2 (polymers P-1 to P-50, comparative polymers CP-1 to CP-10) was dissolved in 10 g of cyclohexanone and filtered through a 0.2 μm filter. The polymer solution was spin-coated onto a Si substrate to form a film with a thickness of 300 nm, which was then evaluated under the following conditions. Etching test with CHF3 / CF4 gas: The difference in film thickness of the polymer film before and after etching was determined using a dry etching apparatus TE-8500P manufactured by Tokyo Electron Limited. The etching conditions are as follows: Chamber pressure 40Pa RF power 1000W Gap 9mm CHF3 gas flow rate: 30 mL / min CF4 gas flow rate: 30 mL / min Ar gas flow rate: 100 mL / min Time 60sec In this evaluation, a film with a small difference in film thickness, that is, a film with a small reduction in film thickness, indicates high etching resistance. The results of the dry etching resistance are shown in Tables 13 to 15.

[0684] [Table 13]

[0685] [Table 14]

[0686] [Table 15]

[0687] From the results shown in Tables 13 to 15, it was confirmed that the polymer of the present invention has excellent dry etching resistance with CHF3 / CF4-based gases.

Claims

1. A sulfonium salt type monomer represented by the following formula (a): 【Chemistry 1】 (In the formula, p is 1, 2, or 3. n1 is 0 or 1. n2 is 1 or 2. n3 is 0, 1, 2, or 3. However, when n1 is 0, 1≦n2+n3≦5, and when n1 is 1, 1≦n2+n3≦7. R 1 is a halogen atom, a nitro group, a cyano group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. 1 may be the same or different, and two R 1 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 2 is a hydrocarbyl group having 1 to 30 carbon atoms which may contain a halogen atom or a heteroatom. When p is 1, two R 2 may be the same or different. + Two of the three substituents bonded to may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Z - is a carboxylic acid anion having an aromatic vinyl structure and an iodine atom.

2. The sulfonium salt type monomer according to claim 1, which is represented by the following formula (a1): 【Chemistry 2】 (In the formula, p, n1 to n3, R 1 and Z - is the same as above. n4 is 0 or 1. n5 is 0, 1, 2, 3, 4 or 5. R 3 is a halogen atom, a nitro group, a cyano group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. 3 may be the same or different, and two R 3 may be bonded to each other to form a ring together with the carbon atoms to which they are attached.)

3. Z - The sulfonium salt type monomer according to claim 1, wherein is an anion represented by the following formula (Z): 【Transformation 3】 (Wherein, m1 is 0 or 1. m2 is 0, 1, 2, 3 or 4. m3 is 0, 1, 2 or 3. m4 is 0 or 1. m5 is 0, 1, 2, 3 or 4. m6 is 0, 1, 2 or 3. m7 is 0 or 1. m8 is 1, 2, 3 or 4. m9 is 0, 1, 2 or 3. m10 is 0 or 1. m11 is 0 or However, when m1 is 0, 0≦m2+m3+m11≦4, and when m1 is 1, 0≦m2+m3+m11≦6. When m4 is 0, 0≦m5+m6≦4, and when m4 is 1, 0≦m5+m6≦6. When m7 is 0, 0≦m8+m9≦5, and when m7 is 1, 0≦m8+m9≦7. Also, 1≦m2+m5+m8≦4. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 4 , R 5 and R 6 are each independently a halogen atom other than an iodine atom, a nitro group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. 4 may be the same or different, and two R 4 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 5 may be the same or different, and two R 5 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 6 may be the same or different, and two R 6 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. L A1 , L A2 , L B1 and L B2 are each independently a single bond, an ether bond, a carbonyl group, an ester bond, a sulfonate ester bond, an amide bond, a sulfonate amide bond, a carbonate bond, or a carbamate bond. X L1 and X L2 are each independently a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom.

4. A sulfonium salt type quencher comprising the sulfonium salt type monomer according to any one of claims 1 to 3.

5. A polymer comprising a repeating unit derived from the sulfonium salt quencher according to claim 4.

6. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (b1) or (b2): 【Chemistry 4】 (In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 represents a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-X 11 - or *-C(=O)-NH-X 11 -, and the phenylene group or naphthylene group may be substituted with a hydroxy group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. 11 is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated hydrocarbylene group may contain a hydroxy group, an ether bond, an ester bond or a lactone ring. X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * indicates a bond to a carbon atom in the main chain. R 11 is a halogen atom, a cyano group, a hydroxy group, a nitro group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. 11 may be the same as or different from each other. AL 1 and AL 2 are each independently an acid labile group. a1 is 0, 1, 2, 3 or 4.

7. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (b3): 【Transformation 5】 (In the formula, b1 is 0 or 1. When b1 is 0, b2 is 0, 1, 2, or 3, and when b1 is 1, b2 is 0, 1, 2, 3, 4, or 5. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 3 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom in the main chain. R 12 and R 13 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 12 and R 13 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 14 is a halogen atom, a hydroxy group, a cyano group, a nitro group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom, or —N(R 14A )(R 14B ) is. R 14A and R 14B are each independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. When b2 is 2 or more, each R 14 may be the same or different, and multiple R 14 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached. X 4 represents a single bond, an aliphatic hydrocarbylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining these groups. X 5 and X 6 are each independently an oxygen atom or a sulfur atom. 4 and X 6 are attached to adjacent carbon atoms of an aromatic ring.)

8. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (c): 【Transformation 6】 (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y 1 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom in the main chain. R 21 represents a halogen atom, a nitro group, a cyano group, a carboxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. c1 is 1, 2, 3, or 4. c2 is 0, 1, 2, or 3, provided that 1≦c1+c2≦5.

9. 6. The polymer according to claim 5, further comprising a repeating unit derived from an onium salt type monomer containing a fluorosulfonate anion having a polymerizable group and at least one iodine atom, and a sulfonium cation.

10. The polymer according to claim 5, further comprising a repeating unit represented by the following formula (e): 【Transformation 7】 (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z 1 represents a single bond, a phenylene group, a naphthylene group, *-C(=O)-O-Z 11 - or *-C(=O)-NH-Z 11 -, and the phenylene group or naphthylene group may be substituted with a hydroxy group, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 10 carbon atoms which may contain a fluorine atom, a saturated hydrocarbyloxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a halogen atom. * represents a bond to a carbon atom in the main chain. Z 11 is a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the saturated hydrocarbylene group may contain a hydroxy group, an ether bond, an ester bond or a lactone ring. R 51 is a hydrogen atom, or a group having 1 to 20 carbon atoms containing at least one structure selected from a hydroxy group other than a phenolic hydroxy group, a cyano group, a carbonyl group, a carboxy group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic acid anhydride (-C(=O)-O-C(=O)-).

11. A chemically amplified resist composition comprising (A) a base polymer comprising the polymer of claim 5.

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

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

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

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

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

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

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