Resist composition and patterning process

Abstract

To provide a non-chemically amplified resist composition excellent in sensitivity and limiting resolution in photolithography using a high energy beam, and a pattern forming method using the resist composition.SOLUTION: The resist composition contains a hypervalent iodine compound (represented by, for example, the following formula), a carboxy group-containing polymer and a solvent. The carboxy group-containing polymer contains a repeating unit of a structure having a specific carboxy group and a repeating unit of a structure of a specific sulfonium salt or iodonium salt.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resist composition and a pattern forming method. [Background technology]

[0002] As the IoT market expands, there is a growing demand for higher integration, higher speeds, and lower power consumption in LSIs, leading to rapid progress in miniaturization of pattern rules. Logic devices, in particular, are driving this miniaturization. The most advanced miniaturization technology is ArF immersion lithography, with double patterning, triple patterning, and quadruple patterning being used to mass-produce 10nm-node devices. Furthermore, studies are underway to develop 7nm-node devices using next-generation extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm.

[0003] As miniaturization progresses, image blurring due to acid diffusion has become a problem (Non-Patent Document 1). It has been suggested that in order to ensure resolution in fine patterns with processing dimensions of 45 nm and below, not only is it important to improve dissolution contrast, as has been proposed in the past, but also to control acid diffusion (Non-Patent Document 2). However, because chemically amplified resist compositions increase sensitivity and contrast through acid diffusion, attempts to minimize acid diffusion by lowering the post-exposure bake (PEB) temperature or shortening the PEB time result in significant decreases in sensitivity and contrast.

[0004] Adding an acid generator that generates bulky acid is effective in suppressing acid diffusion. Therefore, copolymerization of an onium salt acid generator with a polymerizable olefin into a polymer has been proposed. However, for resist film pattern formation with feature sizes of 16 nm or less, it is believed that chemically amplified resist compositions cannot be used to form patterns due to acid diffusion, and the development of non-chemically amplified resist compositions is desired.

[0005] One material for non-chemically amplified resist compositions is polymethyl methacrylate (PMMA), a positive resist material whose main chain is cleaved by EUV irradiation, resulting in a decrease in molecular weight, which improves its solubility in organic solvent developers.

[0006] Hydrogen silsesquioxane (HSQ) is a negative resist material that becomes insoluble in alkaline developers due to crosslinking caused by the condensation reaction of silanols generated by EUV irradiation. Chlorine-substituted calixarenes also function as negative resist materials. These negative resist materials have small molecular size before crosslinking and are free of blurring due to acid diffusion, resulting in low edge roughness and extremely high resolution, and are used as pattern transfer materials to indicate the resolution limit of exposure equipment. However, these materials have insufficient sensitivity, and further improvement is needed.

[0007] One of the challenges in developing materials for EUV lithography is the low photon count in EUV exposure. EUV energy is much higher than that of ArF excimer laser light, and the photon count in EUV exposure is one-fourteenth that of ArF exposure. Furthermore, the pattern dimensions formed with EUV exposure are less than half those of ArF exposure. This makes EUV exposure susceptible to variations in photon count. The variations in photon count in the extremely short wavelength radiation region are a physical phenomenon known as shot noise, and this effect cannot be eliminated. Therefore, so-called stochastics has attracted attention. While the effects of shot noise cannot be eliminated, methods for reducing this effect are being discussed. Shot noise not only increases dimensional uniformity (CDU) and line width roughness (LWR), but also causes hole blockage with a probability of one in several million. Blocked holes cause poor electrical conduction, preventing transistor operation and adversely affecting overall device performance. When considering practical sensitivity, resist compositions containing PMMA or HSQ as the main component are significantly affected by stochastics and are unable to achieve the desired resolution performance.

[0008] As a method for reducing the impact of shot noise on the resist side, the introduction of elements that have high absorption of EUV light has attracted attention. Patent Document 1 proposes a chemically amplified resist composition containing iodine atoms that have high absorption of EUV light. However, as mentioned above, chemically amplified resist compositions cannot achieve excellent resolution performance in EUV lithography, where processing dimensions will become increasingly finer in the future. In particular, in line and space patterns, as pattern dimensions become smaller, pattern collapse and line breakage increase significantly, and reducing these occurrences leads to an improvement in limiting resolution.

[0009] Patent Document 2 proposes a negative resist composition using a tin compound. Because this composition contains tin, which has high absorption of EUV light, as its main component, it has improved stochastics and can achieve high sensitivity and high resolution. However, so-called metal resists of this type have many issues, such as insufficient solubility in resist solvents, storage stability, and defects due to post-etching residues. Furthermore, since metal resists are negative resists in which the exposed areas become insoluble in developer solutions by primarily becoming metal oxides, applying them to contact hole patterning requires an additional reversal process, which raises cost concerns. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2018-5224 [Patent Document 2] Special Publication No. 2021-503482 [Non-patent literature]

[0011] [Non-Patent Document 1] SPIE Vol. 5039 p1 (2003) [Non-patent document 2] SPIE Vol. 6520 p65203L-1 (2007) Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a non-chemically amplified resist composition that exhibits excellent sensitivity and limiting resolution in photolithography using high-energy rays, particularly electron beam (EB) lithography and EUV lithography, and a pattern formation method that uses the resist composition. [Means for solving the problem]

[0013] As a result of extensive research into achieving the above-mentioned object, the present inventors discovered that a resist composition containing as its main components a specific hypervalent iodine compound and a polymer having a carboxy group and a photoacid-generating moiety provides a resist film that exhibits high sensitivity and excellent resolution, and is extremely effective for precise microfabrication, which led to the completion of the present invention.

[0014] That is, the present invention provides the following resist composition and pattern forming method. 1. A resist composition comprising at least one hypervalent iodine compound represented by any one of the following formulas (1) to (4), a carboxy group-containing polymer, and a solvent: The resist composition, wherein the carboxy group-containing polymer comprises a repeating unit represented by the following formula (5), and at least one selected from a repeating unit represented by the following formula (6), a repeating unit represented by the following formula (7), a repeating unit represented by the following formula (8), a repeating unit represented by the following formula (9), and a repeating unit represented by the following formula (10): [ka] (In the formula, m1 is 0, 1 or 2. When m1 is 0, n1 is 1, 2 or 3, and n2 is 0, 1, 2, 3, 4 or 5, and 1≦n1+n2≦6. When m1 is 1, n1 is 1, 2 or 3, and n2 is 0, 1, 2, 3, 4, 5, 6 or 7, and 1≦n1+n2≦8. When m1 is 2, n1 is 1, 2 or 3, and n2 is 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9, and 1≦n1+n2≦10. n3 is 1 or 2. n4 is 0, 1 , 2, 3, or 4, provided that 1≦n3 + n4 ≦ 5. n5 is 1 or 2. n6 is 0, 1, 2, 3, or 4, provided that 1≦n5 + n6 ≦ 5. n7 is 0, 1, 2, 3, or 4. n8 is 1, 2, 3, or 4. m2 is 0, 1, or 2. When m2 is 0, n9 is 0, 1, 2, 3, or 4. When m2 is 1, n9 is 0, 1, 2, 3, 4, 5, or 6. When m2 is 2, n9 is 0, 1, 2, 3, 4, 5, 6, 7, or 8. R 1 ~R 8 are each independently a halogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. 1 and R 2 , R 3 and R 4 , R 5 and R 6 , or R 7 and R 8 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between said carbon atoms. R 11 ~R 14 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n2 is 2 or more, each R 11 may be the same or different, and multiple R 11 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. When n4 is 2 or more, each R 12 may be the same or different, and multiple R 12 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. When n6 is 2 or more, each R13 may be the same or different, and multiple R 13 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. When n7 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. R 15 is an (n8)-valent hydrocarbon group having 1 to 40 carbon atoms or an (n8)-valent heterocyclic group having 2 to 40 carbon atoms, and when n8 is 2, R 15 may be an ether bond, a carbonyl group, an azo group, a thioether bond, a carbonate bond, a carbamate bond, a sulfinyl group, a sulfonyl group, or a thioketone bond. In addition, some or all of the hydrogen atoms of the (n8)-valent hydrocarbon group or the (n8)-valent heterocyclic group may be substituted with a group containing a hetero atom, and some of the -CH2- of the (n8)-valent hydrocarbon group may be substituted with a group containing a hetero atom, and R 14 and R 15 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between said carbon atoms. R 16 is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a halogen atom or a heteroatom. R 17 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n9 is 2 or more, each R 17 may be the same or different. 17 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached. R 18 is a carbonyl group or a hydrocarbylene group having 1 to 10 carbon atoms which may contain a hetero atom. *1 and *2 represent bonds to carbon atoms of the aromatic ring in the formula. However, *1 and *2 are bonded to adjacent carbon atoms of the aromatic ring.) [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. R B are each independently a hydrogen atom or Z 6 may be bonded to form a ring. X 1 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OX 11 -X 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. Z 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. Z 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O- or -Z 31 -O-. Z 31 represents a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, a nitro group, a cyano group, an ester bond, an ether bond, a urethane bond, a fluorine atom, an iodine atom, or a bromine atom. Z 4 is a single bond, a methylene group, or an ethylene group. Z 5represents a single bond, a methylene group, an ethylene group, a phenylene group, a methylphenylene group, a dimethylphenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ 51 -, -C(=O)-OZ 51 - or -C(=O)-NH-Z 51 -It is. Z 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a methylphenylene group, a dimethylphenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a hydroxy group, or a halogen atom. Z 6 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. Z 7A represents a single bond or a divalent organic group having 1 to 24 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. Z 7B is a monovalent organic group having 1 to 10 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. Z 8 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. Z 9 is a trivalent organic group having 1 to 12 carbon atoms, which may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. 1 Reach and Rf 2 may combine to form a carbonyl group. R 21 and R 22 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. R23 is a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. The circle R is an (a+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. a is 0, 1, 2, 3, 4 or 5. X - is a non-nucleophilic counterion. M + is a sulfonium cation or an iodonium cation. 2. The resist composition of 1, wherein the carboxy group-containing polymer does not contain an acid labile group. 3. A laminate comprising a substrate and a resist film obtained from the resist composition 1 or 2 on the substrate. 4. The laminate of 3, further comprising a resist underlayer film between the substrate and the resist film. 5. The laminate of 3 or 4, wherein the resist film is formed by ligand exchange between the hypervalent iodine compound and a carboxy group-containing polymer. 6. A pattern formation method comprising the steps of: forming a resist film on a substrate or a substrate having an underlayer film laminated thereon using the resist composition of 1 or 2; exposing the resist film to i-line, KrF excimer laser, ArF excimer laser, electron beam, or extreme ultraviolet light; and developing the exposed resist film using a developer. [Effects of the Invention]

[0015] The resist composition of the present invention is extremely useful for forming fine patterns, achieving both high sensitivity and high resolution, particularly when using i-line, KrF excimer laser, ArF excimer laser, EB lithography, and EUV lithography. DETAILED DESCRIPTION OF THE INVENTION

[0016] [Resist composition] The resist composition of the present invention contains a predetermined hypervalent iodine compound and a carboxy group-containing polymer as main components.

[0017] [Hypervalent iodine compounds] The hypervalent iodine compound is at least one three-coordinate hypervalent iodine compound represented by any one of the following formulas (1) to (4). [ka]

[0018] In formulas (1) to (4), m1 is 0, 1, or 2. When m1 is 0, n1 is 1, 2, or 3, and n2 is 0, 1, 2, 3, 4, or 5, and 1≦n1+n2≦6. When m1 is 1, n1 is 1, 2, or 3, and n2 is 0, 1, 2, 3, 4, 5, 6, or 7, and 1≦n1+n2≦8. When m1 is 2, n1 is 1, 2, or 3, and n2 is 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9, and 1≦n1+n2≦10. n3 is 1 or 2. n4 is 0, 1, 2, 3, or 4, with the proviso that 1≦n3+n4≦5. n5 is 1 or 2. n7 is 0, 1, 2, 3, or 4, with the proviso that 1≦n5+n6≦5. n7 is 0, 1, 2, 3, or 4. n8 is 1, 2, 3, or 4. m2 is 0, 1, or 2. When m2 is 0, n9 is 0, 1, 2, 3, or 4. When m2 is 1, n9 is 0, 1, 2, 3, 4, 5, or 6. When m2 is 2, n9 is 0, 1, 2, 3, 4, 5, 6, 7, or 8.

[0019] In formulas (1) to (3), R 1 ~R 8 are each independently a halogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. 1 and R 2 , R 3 and R 4 , R 5 and R 6 , or R 7 and R 8 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between said carbon atoms.

[0020] R1 ~R 8 Examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 1 ~R 8 The hydrocarbyl group having 1 to 10 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 10 carbon atoms, such as methyl, ethyl, 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]. 2,6 ] cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms such as a decyl group or an adamantyl group; alkenyl groups such as a vinyl group or an allyl group; aryl groups having 6 to 10 carbon atoms such as a phenyl group or a naphthyl group; and groups obtained by combining these. In addition, 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- in the hydrocarbyl groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms, resulting in the hydrocarbyl groups containing hydroxy groups, cyano groups, halogen atoms, carbonyl groups, ether bonds, thioether bonds, ester bonds, sulfonate ester bonds, carbonate bonds, carbamate bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), etc. 1 ~R 8 is preferably a hydrocarbyl group having 1 to 4 carbon atoms.

[0021] In formulas (1) to (3), R 11 ~R 14 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n2 is 2 or more, each R 11may be the same or different, and multiple R 11 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. When n4 is 2 or more, each R 12 may be the same or different, and multiple R 12 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. When n6 is 2 or more, each R 13 may be the same or different, and multiple R 13 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. When n7 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.

[0022] R 11 ~R 14 Examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 11 ~R 14 The hydrocarbyl group having 1 to 40 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 40 carbon atoms such as methyl, ethyl, 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, an adamantyl group, or an adamantylmethyl 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, cyano groups, halogen atoms, carbonyl groups, ether bonds, thioether bonds, ester bonds, sulfonate ester bonds, carbonate bonds, carbamate bonds, lactone rings, sultone rings, carboxylic anhydrides (-C(=O)-OC(=O)-), or the like.

[0023] In formula (3), R 15 is an (n8)-valent hydrocarbon group having 1 to 40 carbon atoms or an (n8)-valent heterocyclic group having 2 to 40 carbon atoms, and when (n8) is 2, R 15 may be an ether bond, a carbonyl group, an azo group, a thioether bond, a carbonate bond, a carbamate bond, a sulfinyl group, a sulfonyl group, or a thioketone bond. In addition, some or all of the hydrogen atoms of the (n8)-valent hydrocarbon group or the (n8)-valent heterocyclic group may be substituted with a group containing a hetero atom, and some of the -CH2- of the (n8)-valent hydrocarbon group may be substituted with a group containing a hetero atom, and R 14 and R 15 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between said carbon atoms.

[0024] R 15 The (n8)-valent hydrocarbon group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. The (n8)-valent hydrocarbon group is a group obtained by eliminating (n8) hydrogen atoms from a hydrocarbon. Examples of the hydrocarbon include alkanes having 1 to 40 carbon atoms, alkenes having 2 to 40 carbon atoms, alkynes having 2 to 40 carbon atoms, saturated cyclic hydrocarbons having 3 to 40 carbon atoms, unsaturated cyclic hydrocarbons having 3 to 40 carbon atoms, and aromatic hydrocarbons having 6 to 40 carbon atoms.

[0025] Specific examples of the alkanes having 1 to 40 carbon atoms include methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, and structural isomers thereof.

[0026] Specific examples of the alkenes having 2 to 40 carbon atoms include ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, and structural isomers thereof.

[0027] Specific examples of the alkyne having 2 to 40 carbon atoms include acetylene, propyne, butyne, pentyne, hexyne, heptyne, octyne, nonyne, decyne, and structural isomers thereof.

[0028] Specific examples of the cyclic saturated hydrocarbon having 3 to 40 carbon atoms include cyclopropane, cyclobutane, cyclohexane, cycloheptane, cyclooctane, adamantane, and norbornane.

[0029] Specific examples of the cyclic unsaturated hydrocarbon having 3 to 40 carbon atoms include cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, and norbornene.

[0030] Specific examples of the aromatic hydrocarbon having 6 to 40 carbon atoms include benzene, naphthalene, and biphenyl.

[0031] R 15 The (n8)-valent heterocyclic group represented by the following formula is a group obtained by eliminating (n8) hydrogen atoms from a heterocyclic compound. Examples of the heterocyclic compound include furan, pyridine, pyrazole, and thiazolidine.

[0032] R 15The (n8)-valent hydrocarbon group or (n8)-valent heterocyclic group represented by the formula (I) may have some or all of its hydrogen atoms substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and as a result, may contain a hydroxy group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. Furthermore, the (n8)-valent hydrocarbon group may have some of its constituent -CH2- substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, may contain a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a carbamate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), etc.

[0033] In formula (4), R 16 R is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a halogen atom or a heteroatom. 16 Specific examples of the halogen atom and hydrocarbyl group represented by R 1 ~R 8 Examples of the halogen atom and hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0034] In formula (4), R 17 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n9 is 2 or more, each R 17 may be the same or different. 17 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are attached. 17 Specific examples of the halogen atom and hydrocarbyl group represented by R 11 ~R 14 Examples of the halogen atom and hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0035] In formula (4), R 18is a carbonyl group or a hydrocarbylene group having 1 to 10 carbon atoms which may contain a heteroatom. The hydrocarbylene group having 1 to 10 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkylene groups having 1 to 10 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, propane-2,2-diyl group, butane-2,3-diyl group, butane-1,4-diyl group, 2-methylpropane-1,2-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, and decane-1,10-diyl group; cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, adamantanediyl group, and tricyclo[5.2.1.0]diyl group. 2,6 ]Cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms, such as a decanediyl group; alkenylene groups having 2 to 10 carbon atoms, such as a vinylene group or a propynylene group; arylene groups having 6 to 10 carbon atoms, such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group or a naphthylene group; and groups obtained by combining these. 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 -CH2- 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 halogenated alkyl group, a halogen atom, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a carbamate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), or the like. 18 is preferably a carbonyl group, a hydrocarbylene group having 1 to 4 carbon atoms, or a fluorinated hydrocarbylene group having 1 to 4 carbon atoms.

[0036] In formula (4), *1 and *2 represent bonds to the carbon atoms of the aromatic ring in the formula. However, *1 and *2 are bonded to adjacent carbon atoms of the aromatic ring. There are seven possible combinations of *1, *2, and m2, as shown below. [ka] (In the formula, n9, R 17 and R 18 The dashed line indicates R 16 -C(=O)-O- represents a bond.)

[0037] Specific examples of the hypervalent iodine compound represented by formula (1) include, but are not limited to, the following: [ka]

[0038] [ka]

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[0049] Specific examples of the hypervalent iodine compound represented by formula (2) include, but are not limited to, the following: [ka]

[0050] [ka]

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[0053] Specific examples of the hypervalent iodine compound represented by formula (3) include, but are not limited to, the following: [ka]

[0054] [ka]

[0055] [ka]

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[0059] Specific examples of the hypervalent iodine compound represented by formula (4) include, but are not limited to, the following: In the following formula, Me is a methyl group. [ka]

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[0112] [ka]

[0113] [ka]

[0114] [Carboxy group-containing polymer] The carboxyl group-containing polymer contains a repeating unit represented by the following formula (5), and further contains at least one selected from a repeating unit represented by the following formula (6), a repeating unit represented by the following formula (7), a repeating unit represented by the following formula (8), a repeating unit represented by the following formula (9), and a repeating unit represented by the following formula (10). The repeating units represented by the following formulas (6) to (10) are repeating units that function as photoacid generators. [ka]

[0115] In formulas (5) to (10), R A are each independently a hydrogen atom or a methyl group. B are each independently a hydrogen atom or Z 6 may be bonded to form a ring.

[0116] In formula (5), X 1 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OX 11 -X 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.

[0117] Specific examples of the carboxyl group-containing repeating unit represented by formula (5) include, but are not limited to, those shown below. A is the same as above. [ka]

[0118] [ka]

[0119] In formula (6), Z 1represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. Z 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group.

[0120] In formula (6), R 21 and R 22 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 41 ~R 45 Examples of the hydrocarbyl group having 1 to 20 carbon atoms represented by the following formula include the same as those exemplified above.

[0121] Examples of the cation of the monomer that gives the repeating unit represented by formula (6) include, but are not limited to, the following: A is the same as above. [ka]

[0122] In formula (6), X -is a non-nucleophilic counter ion. Specific examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion, fluoroalkylsulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion and nonafluorobutanesulfonate ion, arylsulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion and 1,2,3,4,5-pentafluorobenzenesulfonate ion, alkylsulfonate ions such as mesylate ion and butanesulfonate ion, imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion and bis(perfluorobutylsulfonyl)imide ion, and methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0123] Further examples of the non-nucleophilic counter ion include a sulfonate ion represented by the following formula (6-1) in which the α-position is substituted with a fluorine atom, and a sulfonate ion represented by the following formula (6-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group. [ka]

[0124] In formula (6-1), R 31 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic.

[0125] In formula (6-2), R 32is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and the hydrocarbyl group and hydrocarbylcarbonyl group may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl group and hydrocarbylcarbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic.

[0126] As the non-nucleophilic counter ion, an anion containing an aromatic ring substituted with a bromine atom or an iodine atom, represented by the following formula (6-3), can also be used. [ka]

[0127] In formula (6-3), 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.

[0128] In formula (6-3), X BI is an iodine atom or a bromine atom, and when p and / or q is 2 or more, they may be the same or different.

[0129] In formula (6-3), L 1 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.

[0130] In formula (6-3), L 2 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.

[0131] In formula (6-3), R 33is 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 33A )(R 33B ), -N(R 33C )-C(=O)-R 33D or -N(R 33C )-C(=O)-OR 33D R 33A and R 33B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 33C 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. 33D 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, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 33 may be the same or different from each other.

[0132] Of these, R 33Examples of the hydroxyl group include -N(R 33C )-C(=O)-R 33D , -N(R 33C )-C(=O)-OR 33D fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, etc. are preferred.

[0133] In formula (6-3), Rf 11 ~Rf 14 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. 11 and Rf 12 may combine to form a carbonyl group. 13 and Rf 14 are preferably both fluorine atoms.

[0134] Examples of the anion represented by formula (6-3) include, but are not limited to, the following: BI is the same as above. [ka]

[0135] [ka]

[0136] [ka]

[0137] [ka]

[0138] [ka]

[0139]

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[0140]

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[0141]

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[0142]

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[0143]

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[0144]

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[0145]

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[0146]

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[0147]

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[0148]

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[0149]

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[0150]

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[0151]

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[0152]

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[0153]

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[0154]

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[0155]

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[0156]

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[0157]

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[0158]

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[0159]

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[0160]

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[0161]

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[0162]

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[0163]

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[0164]

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[0165]

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[0166]

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[0167]

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[0168]

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[0169]

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[0170]

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[0171] In formula (7), Z 2 is a single bond or an ester bond. 3 is a single bond, -Z 31 -C(=O)-O- or -Z 31 -O-. Z 31 is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, a nitro group, a cyano group, an ester bond, an ether bond, a urethane bond, a fluorine atom, an iodine atom, or a bromine atom. Z 4 is a single bond, a methylene group, or an ethylene group.

[0172] In formula (7), Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine to form a carbonyl group.

[0173] Examples of the anion of the monomer that gives the repeating unit represented by formula (7) include, but are not limited to, those shown below. A is the same as above. [ka]

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177]

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[0178]

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[0179]

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[0180]

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[0181]

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[0182]

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[0183]

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[0184]

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[0185]

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[0186]

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[0187]

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[0188]

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[0189]

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[0190]

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[0191]

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[0192]

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[0193]

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[0194]

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[0195]

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[0196]

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[0197]

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[0198] In equation (8), Z 5represents a single bond, a methylene group, an ethylene group, a phenylene group, a methylphenylene group, a dimethylphenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ 51 -, -C(=O)-OZ 51 - or -C(=O)-NH-Z 51 -It is. Z 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a methylphenylene group, a dimethylphenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a hydroxy group, or a halogen atom.

[0199] Examples of the anion of the monomer that gives the repeating unit represented by formula (8) include, but are not limited to, those shown below. A is the same as above. [ka]

[0200] [ka]

[0201] In formulas (9) and (10), Z 6 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond.

[0202] In formula (9), Z 7A represents a single bond or a divalent organic group having 1 to 24 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom.

[0203] Z 7AThe divalent organic group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include hydrocarbylene groups having 1 to 24 carbon atoms in which some or all of the hydrogen atoms have been substituted with iodine atoms or bromine atoms. Examples of the hydrocarbylene groups having 1 to 24 carbon atoms include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, and methyl ... alkanediyl groups such as tetradecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, octadecane-1,18-diyl group, nonadecane-1,19-diyl group, and eicosane-1,20-diyl group; cyclopentanediyl group, methylcyclopentanediyl group, dimethylcyclopentanediyl group, trimethylcyclopentanediyl group, tetramethylcyclopentanediyl group, cyclic saturated hydrocarbylene groups such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, tert-butylnaphthylene group, biphenyldiyl group, methylbiphenyldiyl group, dimethylbiphenyldiyl group, and groups obtained by combining these groups. 7A Some or all of the hydrogen atoms of Z may be substituted with a group containing at least one atom selected from an oxygen atom, a nitrogen atom and a sulfur atom;7A A part of -CH2- may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, the compound may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0204] In formula (10), Z 7B is a monovalent organic group having 1 to 10 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom.

[0205] Z 7BThe monovalent organic group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include hydrocarbyl groups having 1 to 10 carbon atoms in which some or all of the hydrogen atoms have been substituted with iodine or bromine atoms. Examples of the hydrocarbyl group having 1 to 10 carbon atoms 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, isopentyl, sec-pentyl, 3-pentyl, tert-pentyl, neopentyl, n-hexyl, n-octyl, n-nonyl, and n-decyl; cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and adamantyl groups. a cyclic saturated hydrocarbyl group having 3 to 10 carbon atoms, such as a norbornyl group, a cyclopropylmethyl group, a cyclopropylethyl group, a cyclobutylmethyl group, a cyclobutylethyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a methylcyclopropyl group, a methylcyclobutyl group, a methylcyclopentyl group, a methylcyclohexyl group, an ethylcyclopropyl group, an ethylcyclobutyl group, an ethylcyclopentyl group, or an ethylcyclohexyl group; a vinyl group alkenyl groups having 2 to 10 carbon atoms such as 1-propenyl group, 2-propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, nonenyl group, and decenyl group; alkynyl groups having 2 to 10 carbon atoms such as ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, heptynyl group, octynyl group, nonynyl group, and decynyl group; cyclopentenyl group, cyclohexenyl group, methylcyclopentenyl group, methylcyclohexenyl group, ethylcyclopentenyl group, ethylcyclohexenyl group, nonenyl group, and cyclopentenyl group. Examples include cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 10 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, and a naphthyl group; aralkyl groups having 7 to 10 carbon atoms, such as a benzyl group, a phenethyl group, a phenylpropyl group, and a phenylbutyl group; and groups obtained by combining these groups.7B Some or all of the hydrogen atoms of Z may be substituted with a group containing at least one atom selected from an oxygen atom, a nitrogen atom and a sulfur atom; 7B A part of -CH2- may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, the compound may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0206] In formulas (9) and (10), Z 8 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms.

[0207] In formula (10), Z 9 is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. 9 The trivalent organic group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include groups obtained by eliminating one hydrogen atom from a hydrocarbylene group having 1 to 12 carbon atoms. Examples of the hydrocarbylene group having 1 to 12 carbon atoms include those having 1 to 12 carbon atoms among the above-mentioned hydrocarbylene groups having 1 to 24 carbon atoms. In addition, Z 9 Some or all of the hydrogen atoms of Z may be substituted with a group containing at least one atom selected from an oxygen atom, a nitrogen atom and a sulfur atom; 9 A part of -CH2- may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, the compound may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0208] In formulas (9) and (10), R 23 is a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group.

[0209] In formulas (9) and (10), the circle R is an (a+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. Specific examples of the (a+2)-valent aromatic hydrocarbon group include groups obtained by eliminating (a+2) hydrogen atoms from aromatic hydrocarbons such as benzene and naphthalene.

[0210] In the formulas (9) and (10), a is an integer of 0 to 5.

[0211] Specific examples of the anion of the repeating unit represented by formula (9) and the repeating unit represented by formula (10) include, but are not limited to, the following. A is the same as above, and X BI is an iodine atom or a bromine atom. [ka]

[0212] [ka]

[0213] [ka]

[0214] [ka]

[0215] [ka]

[0216] [ka]

[0217] [ka]

[0218]

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[0219]

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[0220]

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[0221]

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[0222]

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[0223]

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[0224]

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[0225]

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[0226]

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[0227]

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[0228]

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[0229]

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[0230]

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[0231]

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[0232]

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[0233]

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[0234]

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[0235]

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[0236]

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[0237]

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[0238]

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[0239]

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[0240]

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[0241]

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[0242]

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[0243]

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[0244]

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[0245]

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[0246]

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[0247]

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[0248]

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[0249]

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[0250]

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[0251]

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[0252]

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[0253]

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[0254]

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[0255]

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[0256]

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[0257]

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[0258]

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[0259]

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[0260]

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[0261] [ka]

[0262] [ka]

[0263] In formulas (7) to (10), M + is a sulfonium cation or an iodonium cation. The sulfonium cation is preferably one represented by the following formula (M-1), and the iodonium cation is preferably one represented by the following formula (M-2). [ka]

[0264] In formulas (M-1) and (M-2), R 41 ~R 45 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0265] R 41 ~R 45 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.

[0266] R 41 ~R 45The hydrocarbyl group having 1 to 20 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 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; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, propenyl, butenyl, and hexenyl groups; and ethynyl groups. alkynyl groups having 2 to 20 carbon atoms such as a propynyl group or a butynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms such as a cyclohexenyl group or a norbornenyl group; aryl groups having 6 to 20 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 or a tert-butylnaphthyl group; aralkyl groups having 7 to 20 carbon atoms such as a benzyl group or a phenethyl group; and groups obtained by combining these.

[0267] 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 mercapto 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.

[0268] Also, R 41 and R 42 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring preferably has the following structure: [ka] (In the formula, the dashed lines represent bonds.)

[0269] M + Specific examples of the sulfonium cation represented by the formula (I) include, but are not limited to, those shown below. [ka]

[0270] [ka]

[0271] [ka]

[0272] [ka]

[0273]

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[0274]

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[0275]

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[0276]

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[0277]

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[0279]

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[0280]

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[0281]

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[0286]

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[0287]

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[0289]

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[0299]

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[0305] M + Specific examples of the iodonium cation represented by the formula (I) include, but are not limited to, those shown below. [ka]

[0306] [ka]

[0307] The carboxy group-containing polymer may further contain repeating units other than the carboxy group-containing repeating units (hereinafter also referred to as "other repeating units"). Preferred other repeating units include a unit that undergoes salt exchange with sulfonic acid generated from the photoacid generator unit in exposed areas to generate carboxylic acid and function as a quencher.

[0308] As a monomer that provides such a repeating unit that functions as a quencher, an onium salt of a carboxylic acid having a polymerizable group is preferred. Specific examples of the cation of the onium salt are a sulfonium cation represented by formula (M-1) and an iodonium cation represented by formula (M-2). Specific examples of the anion of the onium salt include, but are not limited to, the following. In the following formula, R A is the same as above. [ka]

[0309] [ka]

[0310] [ka]

[0311] [ka]

[0312]

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[0313]

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[0314]

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[0315]

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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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[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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[0340]

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[0342] Other examples of preferred other repeating units include those that can improve the solubility in solvents of polymers that are poorly soluble in a repeating unit having a carboxyl group alone, as well as those that are mainly composed of a repeating unit having a cyclic structure with a rigid skeleton that is expected to provide high etching resistance, or a repeating unit having a styrene skeleton.

[0343] Specific examples of the other repeating units include, but are not limited to, those shown below. A is the same as above, and X B are each independently —CH— or —O—. [ka]

[0344] [ka]

[0345] [ka]

[0346] [ka]

[0347] [ka]

[0348] [ka]

[0349] [ka]

[0350] [ka]

[0351]

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[0352]

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[0359]

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[0360]

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[0361]

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[0363]

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[0364]

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[0369]

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[0370]

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[0371]

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[0372] [ka]

[0373] Specific examples of the repeating units represented by formulas (6) to (10) include any combination of the above-mentioned anions and cations.

[0374] The repeating units represented by formulas (6) to (10) may be used singly or in combination of two or more.

[0375] By bonding the photoacid generator to the polymer, the diffusion of the acid generated in the exposed area is suppressed, making it possible to form a pattern with excellent resolution. Furthermore, when the photoacid generator is bonded to the polymer, the photoacid generator is dispersed more uniformly in the resist film and the glass transition temperature of the resist is also increased compared to when the photoacid generator is added without being bonded to the polymer, making it possible to create a high-resolution pattern with reduced roughness.

[0376] When the repeating units represented by formulas (6) to (10) contain an element that has a high absorption effect on EUV light, such as a fluorine atom or an iodine atom, the amount of secondary electrons generated increases, promoting the decomposition of cations, and therefore, they are suitable for forming highly sensitive fine patterns.

[0377] In the carboxyl group-containing polymer, the content of the carboxyl group-containing repeating unit represented by formula (5) is preferably 10 to 95 mol %, more preferably 20 to 80 mol %. The content of the photoacid generator repeating unit represented by formulas (6) to (10) is preferably 5 to 40 mol %, more preferably 10 to 30 mol %. The content of other repeating units is preferably 0 to 50 mol %, more preferably 10 to 40 mol %.

[0378] The weight average molecular weight (Mw) of the carboxy group-containing polymer is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. In the present invention, Mw is a value measured in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[0379] Furthermore, if the carboxyl group-containing polymer has a broad molecular weight distribution (Mw / Mn), the presence of low-molecular-weight and high-molecular-weight polymers may result in the appearance of foreign matter on the pattern after exposure, or the pattern shape may be deteriorated. Therefore, since the effects of Mw and Mw / Mn tend 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 the carboxyl group-containing polymer have a narrow Mw / Mn distribution of 1.0 to 2.0.

[0380] In the resist composition of the present invention, the molar ratio of the hypervalent iodine compound to the carboxylic acid-containing repeating units in the carboxyl group-containing polymer is preferably hypervalent iodine compound:carboxyl group-containing polymer = 10:90 to 90:10, more preferably 20:80 to 80:20, and even more preferably 30:70 to 70:30. The hypervalent iodine compounds may be used alone or in combination of two or more. The carboxyl group-containing polymers may be used alone or in combination of two or more with different composition ratios, Mw, and / or Mw / Mn.

[0381] The carboxyl group-containing 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.

[0382] Specific examples of organic solvents used in the polymerization reaction include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, cyclopentanone, cyclohexanone, methyl ethyl ketone (MEK), propylene glycol monomethyl ether (PGME), 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% of the total amount of monomers to be polymerized. The reaction temperature is preferably 50 to 150° C., more preferably 60 to 100° C. The reaction time is preferably 2 to 24 hours, more preferably 2 to 12 hours from the viewpoint of production efficiency.

[0383] 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 each may be 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. 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 these chain transfer agents added is preferably 0.01 to 20 mol % of the total amount of monomers to be polymerized.

[0384] 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.

[0385] [solvent] The resist composition contains a solvent. The solvent is not particularly limited as long as it can dissolve the hypervalent iodine compound, the carboxyl group-containing polymer, and other components described below and can form a film. Such a solvent is preferably an organic solvent, and specific examples thereof include ketones such as cyclohexanone, methyl-2-n-pentyl ketone, and methyl isoamyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, 4-methyl-2-pentanol, and methyl 2-hydroxyisobutyrate; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether; Examples of suitable solvents include ethers such as propylene glycol dimethyl ether and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, 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; carboxylic acids such as formic acid, acetic acid, and propionic acid; lactones such as γ-butyrolactone; and mixed solvents thereof.

[0386] The content of the solvent in the resist composition of the present invention is preferably an amount such that the solids concentration in the resist composition is 0.1 to 20 mass%, more preferably 0.1 to 15 mass%, and even more preferably 0.1 to 10 mass%. In the present invention, the term "solids" refers collectively to all components of the resist composition other than the solvent. The solvents may be used alone or in combination of two or more.

[0387] [Other ingredients] The resist composition of the present invention may contain a quencher. Examples of the quencher include basic compounds. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. Particularly preferred are the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A, particularly amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond, and compounds having a carbamate group described in Japanese Patent No. 3790649 A. Addition of such basic compounds can, for example, further suppress the diffusion rate of acid in the resist film or correct the shape.

[0388] Further examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids not fluorinated at the α-position, as described in JP 2008-158339 A. Sulfonic acids, imido acids, or methide acids fluorinated at the α-position are released as sulfonic acids or carboxylic acids not fluorinated at the α-position by salt exchange with onium salts not fluorinated at the α-position. Sulfonic acids and carboxylic acids not fluorinated at the α-position function as quenchers because they are less susceptible to ligand exchange with hypervalent iodine compounds. Other examples of quenchers include onium salts of carboxylic acids fluorinated at the α-position, as described in Japanese Patent No. 5904180 A. α-Fluorocarboxylic acids have lower acidity than sulfonic acids and therefore have high quenching ability, allowing the formation of patterns with good roughness and resolution.

[0389] When the resist composition of the present invention contains the quencher, the amount thereof is preferably 0 to 10 parts by mass, and more preferably 0 to 7 parts by mass, per 100 parts by mass of the resist material. The other quenchers can be used alone or in combination of two or more.

[0390] The resist composition of the present invention may further contain a surfactant. The surfactant is preferably a fluorine-based and / or silicone-based surfactant. Examples of such surfactants include those described in paragraph

[0276] of U.S. Patent Application Publication No. 2008 / 0248425. Furthermore, surfactants other than the fluorine-based and / or silicone-based surfactants described in paragraph

[0280] of U.S. Patent Application Publication No. 2008 / 0248425 may also be used.

[0391] When the resist composition of the present invention contains the surfactant, the content thereof is preferably 0.0001 to 2 mass % of the total solid content. The surfactant may be used alone or in combination of two or more.

[0392] The resist composition of the present invention may further contain a radical scavenger. By adding a radical scavenger, it is possible to control the photoreaction during photolithography and adjust the sensitivity.

[0393] Examples of the radical scavenger include hindered phenols, quinones, hindered amines, and thiol compounds. Specific examples of hindered phenols include dibutylhydroxytoluene (BHT) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol). Examples of quinones include 4-methoxyphenol (methoquinone) and hydroquinone. Examples of hindered amines include 2,2,6,6-tetramethylpiperidine and 2,2,6,6-tetramethylpiperidine-N-oxy radical. Examples of thiols include dodecanethiol and hexadecanethiol.

[0394] When the resist composition of the present invention contains the radical scavenger, the content thereof is preferably 0.01 to 10 mass % of the total solid content. The radical scavenger may be used alone or in combination of two or more.

[0395] The resist composition of the present invention may further contain a crosslinking agent. Addition of the crosslinking agent promotes the crosslinking reaction during photolithography, improves the glass transition temperature of the pattern, and enables the production of a pattern with excellent fine-line resolution.

[0396] Examples of the crosslinking agent include compounds having a carbon-carbon unsaturated bond as a functional group, such as a vinyl group, a (meth)acrylate group, an allyl group, an alkynyl group, or an aromatic ring. Specific examples of compounds having a vinyl group include linear alkenes, branched alkenes, and cyclic alkenes, which may have a substituent. Examples of compounds having a (meth)acrylate group include acrylic acid, methacrylic acid, acrylic acid esters, and methacrylic acid esters, which may have a substituent. Examples of compounds having an allyl group include allyl alcohols, allyl ethers, allyl esters, allyl amides, allyl amines, and allyl group-containing isocyanurates, which may have a substituent. Examples of compounds having an alkynyl group include linear alkynes, branched alkynes, cyclic alkynes, alkynyl alcohols, alkynyl ethers, alkynyl esters, alkynyl amides, alkynyl amines, and alkynyl group-containing isocyanurates, which may have a substituent. Examples of compounds having an aromatic ring include arenes, heteroarenes, styrene, stilbene, phenylacetylene, acenaphthylene, chalcone, and the like, which may have a substituent. The crosslinking agent may have only one or more of the functional groups. The number of functional groups contained in the crosslinking agent is preferably 1 to 10, and more preferably 2 to 8.

[0397] When the resist composition of the present invention contains the crosslinking agent, the content thereof is preferably 0.01 to 50 mass % of the total solid content. The crosslinking agents may be used alone or in combination of two or more.

[0398] When the resist composition of the present invention contains the crosslinking agent, it may further contain a photopolymerization initiator. The photopolymerization initiator generates radicals when irradiated with high-energy rays, and can promote crosslinking of the crosslinking agent.

[0399] Specific examples of the photopolymerization initiator include benzophenone, methyl O-benzoylbenzoate, 4-benzoyl-4'-methyldiphenyl ketone, dibenzyl ketone, fluorenone and other benzophenone derivatives; 2,2'-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino acetophenone derivatives such as 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]-phenyl}-2-methylpropan-1-one and methyl phenylglyoxylate; thioxanthone derivatives such as thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone and diethylthioxanthone; benzil, benzil dimethyl ketal ... Benzyl derivatives such as benzyl-β-methoxyethyl acetal; benzoin, benzoin methyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and other benzoin derivatives; 1-phenyl-1,2-butanedione-2-(O-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(O-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl)oxime, 1-phenyl-1, Oxime compounds such as 2-propanedione-2-(O-benzoyl)oxime, 1,3-diphenylpropanetrione-2-(O-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(O-benzoyl)oxime-1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)]ethanone, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime);α-Hydroxyketone compounds such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropane; 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl) Examples of suitable compounds include α-aminoalkylphenone compounds such as butan-1-one; phosphine oxide compounds such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; and titanocene compounds such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium.

[0400] When the resist composition of the present invention contains the photopolymerization initiator, its content is preferably 0.1 to 10 mass %, more preferably 0.1 to 5 mass %, and most preferably 0.1 to 1 mass %, based on the total solid content. When the content is 0.1 mass % or more, a sufficient blending effect can be obtained.

[0401] As described above, the resist composition of the present invention contains a hypervalent iodine compound and a carboxyl group-containing polymer as main components, but does not contain an acid-labile group-containing polymer as contained in conventional chemically amplified resist compositions. However, the resist composition of the present invention can form a positive-tone pattern, particularly by EB or EUV exposure, in which the exposed portion becomes soluble in a developer. The mechanism behind this is not completely clear, but is presumed to be as follows.

[0402] The hypervalent iodine compounds represented by formula (1), (2), (3), or (4) are tricoordinate compounds having an aryl group and a carboxylate ligand. It is believed that when such tricoordinate iodine compounds are mixed with a carboxyl group-containing polymer, an exchange of the carboxylate ligand occurs via an equilibrium reaction. If the original carboxylate ligand can be removed in some way, a hypervalent iodine compound with a new ligand is generated. For example, 1-iodonaphthylene diacetate, a hypervalent iodine compound, is mixed with a carboxyl group-containing polymer, and the resulting low-boiling acetic acid is removed to complete the ligand exchange. The carboxyl group-containing polymer then becomes a crosslinked polymer via the hypervalent iodine compound.

[0403] Polymers crosslinked with hypervalent iodine compounds are generated during film formation. This is because even if such crosslinked polymers are synthesized in advance, they are insoluble in most organic solvents, making it impossible to prepare a solution. This is presumably because hypervalent iodine compounds, which have low solvent solubility due to their inherent high polarization, become even less soluble when a carboxyl group-containing polymer is used as a ligand. Therefore, it is desirable to complete the ligand exchange reaction and form a resist film by removing the original low-molecular-weight carboxylic acid component during film formation and the subsequent baking process.

[0404] In the resist film obtained from the resist composition of the present invention, the polarity of the hypervalent iodine compound, which is the main component, changes when exposed to light, and a pattern is formed by the development step. The mechanism by which this occurs is not completely clear, but is presumed to be as follows, for example.

[0405] The resist film obtained from the resist composition of the present invention contains a polymer to which a hypervalent iodine compound is bonded during film formation. However, when this polymer is decomposed by light, it becomes a monovalent iodine compound, and at the same time, the bond between the carboxyl group-containing polymer and the hypervalent iodine compound is released, resulting in a decrease in molecular weight. As a result, a positive pattern is formed in which the exposed areas are removed by an organic solvent. Therefore, it is presumed that the resist composition functions as a positive resist composition.

[0406] The resist composition of the present invention, which contains a hypervalent iodine compound and a carboxyl group-containing polymer having a photoacid generator unit, is capable of forming a positive pattern with higher sensitivity than a resist composition containing no photoacid generator. The mechanism by which this occurs is not completely clear, but is presumed to be, for example, as follows.

[0407] In the resist composition of the present invention, the carboxyl group-containing polymer contains a photoacid generator unit, and the acid generated from the photoacid generator unit during the resist exposure step exchanges with the ligand of the hypervalent iodine compound to form a new ligand, thereby releasing the bond between the carboxyl group-containing polymer and the hypervalent iodine compound. Therefore, in addition to the scission of the I-O bond by light, the acid generated from the photoacid generator exchanges with the new ligand, resulting in polarity conversion or molecular weight reduction, and it is presumed that this enables the formation of a positive pattern with high sensitivity by organic solvent development.

[0408] Based on the above speculation, the resist composition of the present invention is a non-chemically amplified resist composition containing a polymer containing a photoacid generator unit, and does not require a polymer containing an acid labile group as in conventional chemically amplified resist compositions. Therefore, the acid generated from the photoacid generator reacts with the ligand of the hypervalent iodine compound in the exposed area to form a new hypervalent iodine ligand. In other words, unlike chemically amplified resist compositions, the resist composition does not have an amplification mechanism that reacts with an acid labile group to regenerate acid, and therefore does not suffer from adverse effects due to acid diffusion (e.g., image blurring), and can resolve fine patterns.

[0409] The resist composition of the present invention is particularly effective in EUV lithography because it contains iodine atoms with high absorption capacity for EUV light, which reduces shot noise and enables the achievement of higher resolution and lower LWR.

[0410] Metal resists containing metal tin compounds as their main component, which have high absorption capacity for EUV light similar to that of iodine atoms, have been reported as EUV resist compositions capable of forming fine patterns (e.g., Patent Document 2). However, as mentioned above, such metal resists have many problems, such as insufficient solubility in solvents, poor storage stability, and defects due to post-etching residues caused by the inclusion of metal elements. On the other hand, the resist composition of the present invention is advantageous over metal resists in terms of defects because it does not contain metal elements, and it also has no problems with solubility in solvents. Furthermore, the resist composition of the present invention can be used in positive resists. For example, in the contact hole formation process, metal resists developed using negative development require a reversal process step after pillar pattern formation, whereas positive resists do not require such a step. Therefore, from the perspective of process simplicity, the resist composition of the present invention can be said to be more useful than metal resists.

[0411] Japanese Patent Publication No. 2015-180928 and Japanese Patent Publication No. 2018-95853 describe resist compositions containing a hypervalent iodine compound as an additive, and resist compositions incorporating a hypervalent iodine compound into the polymer backbone of a base polymer. However, the characteristics of the resist compositions described in these patent documents are limited to the description that they are chemically amplified resist compositions in which acid labile groups are essential in the polymer units and that they can improve line edge roughness. There is no mention whatsoever of the possibility of the hypervalent iodine compound being photodecomposed or functioning as a material for a non-chemically amplified resist composition. Furthermore, according to the descriptions of the blending amounts and specific examples, the hypervalent iodine compound is not the main component. Therefore, it is believed that these patent documents do not suggest a material that can reduce shot noise in EUV lithography and form fine patterns as a material for a non-chemically amplified resist composition, as described in the present invention. In other words, it can be said that the present invention provides a clearly novel resist composition and pattern formation method.

[0412] [Pattern formation method] When the 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 resist composition, or on an underlayer film of a substrate having an underlayer film laminated thereon; exposing the resist film to high-energy rays; and, if necessary, developing the exposed resist film using a developer.

[0413] First, the resist composition of the present invention is applied to a substrate for integrated circuit manufacturing, or to a substrate having a laminated underlayer film (e.g., Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coating), or to a substrate for mask circuit manufacturing, or to a substrate having a laminated underlayer film (e.g., CrO, CrON, MoSi2, SiO2), using an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, to a coating thickness of 0.01 to 2 μm. This is then prebaked on a hot plate, preferably at 60 to 200°C for 10 seconds to 30 minutes, more preferably at 80 to 180°C for 30 seconds to 20 minutes, to form a resist film. The underlayer film refers to a film formed between the substrate and the resist film in a multilayer resist process. The underlayer film is not particularly limited, and conventionally known underlayer films can be used.

[0414] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, EB, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When ultraviolet radiation, far ultraviolet radiation, EUV, 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 300 mJ / cm, either directly or using a mask for forming a desired pattern. 2 approximately, more preferably 10 to 200 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 8000 μC / cm 2 directly or using a mask for forming a desired pattern. 2 approximately, more preferably 0.5 to 5000 μC / cm 2 The resist composition of the present invention is particularly suitable for fine patterning using high-energy rays such as EB or EUV.

[0415] After exposure, PEB is performed as needed, preferably on a hot plate or in an oven at 30 to 200°C for 10 seconds to 30 minutes, more preferably at 60 to 120°C for 30 seconds to 20 minutes.

[0416] After exposure or PEB, the film is developed with a developer as needed to perform patterning. The developer used in this case may be an aqueous alkali solution such as an aqueous tetramethylammonium hydroxide solution or an aqueous tetrabutylammonium hydroxide solution; 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, 5-methyl-2-hexanone, methylcyclohexanone, acetophenone, methylacetophenone, isopropyl alcohol, isoamyl alcohol, n-butanol, tert-butyl alcohol, tert-pentyl alcohol, n-pentanol, cyclohexanol, formic acid, acetic acid, propionic acid, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, cyclohexyl acetate, 4-tert-butylcyclohexyl acetate, octyl acetate, isobornyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, chloroform ... Ethyl lactate, 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, ethyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate Examples of organic solvents that can be used include ethyl acetate, 2-phenylethyl acetate, 2-propanol, 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 3-methyl-1-butanol, diacetone alcohol, 4-methyl-2-pentanol, 3-methylcyclohexanol, 3,5,5-trimethylhexyl alcohol, 2,6-dimethyl-4-heptanol, toluene, anisole, and ε-caprolactone. These developers may be used alone or in combination of two or more.

[0417] After development, rinsing is performed as necessary. 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.

[0418] 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. [Example]

[0419] 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.

[0420] [1] Synthesis of carboxyl group-containing polymers The monomers used in the synthesis of polymers P-1 to P-8 are as follows. [ka]

[0421] [ka]

[0422] [ka]

[0423] [ka]

[0424] [Synthesis Example 1-1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, a flask was charged with 44 g of monomer b-1, 21 g of monomer c-1, 35 g of monomer d-1, 5.4 g of V-601 (Fujifilm Wako Pure Chemical Industries, Ltd.), and 180 g of MEK to prepare a monomer-polymerization initiator solution. 55 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, the polymerization solution was stirred for 2 hours while maintaining the temperature at 80°C, and then cooled to room temperature. The resulting polymerization solution was added dropwise to 4,000 g of vigorously stirred hexane, and the precipitated polymer was filtered off. The resulting polymer was washed twice with 1,200 g of hexane and then vacuum-dried at 50°C for 20 hours to obtain polymer P-1 as a white powder (yield: 98 g, 98%). Polymer P-1 had an Mw of 7500 and an Mw / Mn of 1.41. Note that Mw was a value measured in terms of polystyrene by GPC using THF as a solvent. [ka]

[0425] [Synthesis Examples 2 to 8] Synthesis of polymers P-2 to P-8 The polymers shown in Table 1 below were synthesized in the same manner as in Synthesis Example 1, except that the types and blending ratios of the respective monomers were changed.

[0426] [Table 1]

[0427] [2] Preparation of resist composition [Examples 1-1 to 1-12, Comparative Examples 1-1 to 1-6] Resist compositions (R-01 to R-12 and CR-01 to CR-04) were prepared by dissolving a hypervalent iodine compound, a carboxyl group-containing polymer, and a sensitivity modifier in a solvent containing 0.01% by mass of a surfactant (PF-636, Omnova) according to the compositions shown in Table 2 below, and filtering the resulting solution through a 0.2 μm Teflon (registered trademark) filter. Resist compositions (CR-05 and CR-06) were also prepared by dissolving a polymer, a photoacid generator, and a sensitivity modifier in a solvent containing 0.01% by mass of a surfactant (PF-636, Omnova) according to the compositions shown in Table 3 below, and filtering the resulting solution through a 0.2 μm Teflon (registered trademark) filter.

[0428] [Table 2]

[0429] [Table 3]

[0430] In Tables 2 and 3, the hypervalent iodine compounds I-1 to I-3, photoacid generators PAG-1 to PAG-3, sensitivity adjusters Q-1 and Q-2, and solvents are as follows. [ka]

[0431] [ka]

[0432] [ka]

[0433] Solvent: PGMEA (propylene glycol monomethyl ether acetate) AcOH (acetic acid) GBL (γ-butyrolactone)

[0434] [3] EUV lithography evaluation (line and space patterns) [Examples 2-1 to 2-12, Comparative Examples 2-1 to 2-6] Each resist composition (R-01 to R-12, CR-01 to CR-06) was spin-coated onto a Si substrate coated with a 20 nm thick silicon-containing spin-on hard mask (SHB-A940, manufactured by Shin-Etsu Chemical Co., Ltd.) (43% silicon by mass), and then prebaked (PAB) for 60 seconds on a hot plate at the temperature listed in Table 4 to produce a 40 nm thick resist film. The resist film was then exposed to light using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9, 90-degree dipole illumination) to form a 36 nm line-and-space (LS) 1:1 pattern. Then, PEB was performed on a hot plate at the temperature listed in Table 4 for 60 seconds, followed by development for 30 seconds in the developer listed in Table 4 to form an LS pattern with a space width of 18 nm and a pitch of 36 nm.

[0435] The resulting resist patterns were evaluated as follows, and the results are shown in Table 4.

[0436] [Sensitivity evaluation] The LS pattern was observed using a length measurement SEM (CG-6300) manufactured by Hitachi High-Tech Corporation, and the optimum exposure dose Eop (mJ / cm) for obtaining an LS pattern with a space width of 18 nm and a pitch of 36 nm was determined. 2 ) was calculated and used as the sensitivity.

[0437] [LWR rating] The LS pattern obtained by irradiation with the optimum exposure dose was measured at 10 points in the longitudinal direction of the space width using a critical dimension SEM (CG-6300) manufactured by Hitachi High-Tech Corporation, 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 space width pattern obtained.

[0438] [Limiting resolution evaluation] The limiting line width (nm) that can be resolved when forming a pattern by gradually increasing the exposure dose from the optimum exposure dose at which the LS pattern is formed was determined using a critical dimension SEM (CG-6300) manufactured by Hitachi High-Technologies Corporation, and this was taken as the limiting resolution (nm). The smaller this value, the better the limiting resolution, indicating that a finer pattern can be formed.

[0439] [Table 4]

[0440] Developer: nBA (butyl acetate) TMAH (2.38% by mass tetramethylammonium hydroxide aqueous solution)

[0441] From the results shown in Table 4, comparing Example 2-1 and Comparative Example 2-1, it was found that introducing a photoacid generator unit into the polymer enabled pattern formation with high sensitivity. Comparing Example 2-1 and Comparative Example 2-2, Example 2-4 and Comparative Example 2-3, and Example 2-11 and Comparative Example 2-4, it was found that incorporating a photoacid generator unit into the polymer provided a better resolution limit than adding a photoacid generator. Comparing Examples 2-1 to 2-3, it was found that the higher the proportion of photoacid generator units in the polymer, the higher the pattern formation sensitivity. Comparing Example 2-1 and Examples 2-11 to 2-12, it was found that adding a sensitivity adjuster enabled adjustment of sensitivity toward the lower sensitivity side, resulting in excellent resolution. The resist composition of the present invention exhibited superior sensitivity, resolution, and LWR, even compared to Comparative Examples 2-5 and 2-6, which were chemically amplified resist compositions using an acid-catalyzed reaction. Therefore, it was found that the resist composition of the present invention was capable of forming resist patterns with excellent sensitivity in LS pattern formation by EUV exposure.

[0442] [4] EUV lithography evaluation (contact hole pattern) [Examples 3-1 to 3-12, Comparative Examples 3-1 to 3-6] Each resist composition (R-01 to R-12, CR-01 to CR-06) was spin-coated onto a Si substrate with a 20 nm thick silicon-containing spin-on hard mask SHB-A940 (43% silicon by mass) manufactured by Shin-Etsu Chemical Co., Ltd., and then subjected to PAB for 60 seconds at the temperature listed in Table 5 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, wafer dimensions 64 nm pitch, +20% bias hole pattern mask), subjected to PEB for 60 seconds on a hot plate at the temperature listed in Table 5, and developed for 30 seconds using the developer listed in Table 5 to obtain a 32 nm hole pattern.

[0443] The resulting resist patterns were evaluated as follows, and the results are shown in Table 5.

[0444] [Sensitivity evaluation] The contact hole pattern was observed using a length measuring SEM (CG-6300) manufactured by Hitachi High-Tech Corporation, and the optimum exposure dose Eop (mJ / cm) for obtaining a hole pattern with a dimension of 32 nm was determined. 2 ) was calculated and used as the sensitivity.

[0445] [CDU Rating] The dimensions of 50 hole patterns obtained by irradiation with the optimal exposure dose were measured, and the CDU was calculated as three times the standard deviation (σ). The smaller this value, the more uniform the hole diameter pattern.

[0446] [Limiting resolution evaluation] The limiting hole diameter (nm) that can be resolved when forming a hole pattern by gradually decreasing the exposure dose from the optimum exposure dose required to form the hole pattern was determined using a critical dimension SEM (CG-6300) manufactured by Hitachi High-Technologies Corporation, and this was taken as the limiting resolution (nm). The smaller this value, the better the limiting resolution, indicating that a pattern with a finer hole diameter can be formed.

[0447] [Table 5]

[0448] Developer: nBA (butyl acetate) TMAH (2.38% by mass tetramethylammonium hydroxide aqueous solution)

[0449] From the results shown in Table 5, comparing Example 3-1 and Comparative Example 3-1, it was found that introducing a photoacid generator unit into the polymer enabled pattern formation with high sensitivity. Comparing Example 3-1 and Comparative Example 3-2, Example 3-4 and Comparative Example 3-3, and Example 3-11 and Comparative Example 3-4, it was found that incorporating a photoacid generator unit into the polymer provided a better resolution limit than adding a photoacid generator. Comparing Examples 3-1 to 3-3, it was found that the higher the proportion of photoacid generator units in the polymer, the higher the pattern formation sensitivity. Comparing Example 3-1 and Examples 3-11 to 3-12, it was found that adding a sensitivity adjuster enabled adjustment of sensitivity toward the lower sensitivity side, resulting in excellent resolution. The resist composition of the present invention exhibited superior sensitivity, resolution, and CDU, even compared to Comparative Examples 3-5 and 3-6, which were chemically amplified resist compositions using an acid-catalyzed reaction. Therefore, it was found that the resist composition of the present invention was capable of forming a resist pattern with excellent sensitivity when forming a contact hole pattern by EUV exposure.

Claims

1. A resist composition comprising at least one hypervalent iodine compound represented by any one of the following formulas (1) to (4), a carboxy group-containing polymer, and a solvent: The resist composition, wherein the carboxy group-containing polymer comprises a repeating unit represented by the following formula (5), and at least one selected from a repeating unit represented by the following formula (6), a repeating unit represented by the following formula (7), a repeating unit represented by the following formula (8), a repeating unit represented by the following formula (9), and a repeating unit represented by the following formula (10): 【Chemistry 1】 (In the formula, m1 is 0, 1, or 2. When m1 is 0, n1 is 1, 2, or 3, and n2 is 0, 1, 2, 3, 4, or 5, and 1≦n1+n2≦6. When m1 is 1, n1 is 1, 2 or 3, and n2 is 0, 1, 2, 3, 4, 5, 6 or 7, and 1≦n1+n2≦8. When m1 is 2, n1 is 1, 2, or 3, and n2 is 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9, and 1≦n1+n2≦10. n3 is 1 or 2. n4 is 0, 1, 2, 3, or 4, provided that 1≦n3+n4≦5. n5 is 1 or 2. n6 is 0, 1, 2, 3, or 4, provided that 1≦n5+n6≦5. n7 is 0, 1, 2, 3, or 4. n8 is 1, 2, 3, or 4. m2 is 0, 1, or 2. When m2 is 0, n9 is 0, 1, 2, 3, or 4. When m2 is 1, n9 is 0, 1, 2, 3, 4, 5, or 6. When m2 is 2, n9 is 0, 1, 2, 3, 4, 5, 6, 7 or 8. R 1 ~R 8 are each independently a halogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. 1 and R 2 , R 3 and R 4 , R 5 and R 6 , or R 7 and R 8 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between said carbon atoms. R 11 ~R 14 are each independently a halogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. When n2 is 2 or more, each R 11 may be the same or different, and multiple R 11 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. 12 may be the same or different, and multiple R 12 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. 13 may be the same or different, and multiple R 13 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. 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 bonded. R 15 is an (n8)-valent hydrocarbon group having 1 to 40 carbon atoms or an (n8)-valent heterocyclic group having 2 to 40 carbon atoms, and when n8 is 2, R 15 may be an ether bond, a carbonyl group, an azo group, a thioether bond, a carbonate bond, a carbamate bond, a sulfinyl group, a sulfonyl group, or a thioketone bond. In addition, some or all of the hydrogen atoms of the (n8)-valent hydrocarbon group or the (n8)-valent heterocyclic group may be substituted with a group containing a hetero atom, and the -CH of the (n8)-valent hydrocarbon group may be substituted with a group containing a hetero atom. 2 A part of - may be substituted with a group containing a hetero atom, 14 and R 15 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded and the atoms between said carbon atoms. R 16 is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a halogen atom or a heteroatom. R 17 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a halogen atom or a heteroatom. When n9 is 2 or more, each R 17 may be the same or different. 17 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. R 18 is a carbonyl group or a hydrocarbylene group having 1 to 10 carbon atoms which may contain a heteroatom. *1 and *2 represent bonds to carbon atoms of the aromatic ring in the formula. However, *1 and *2 are bonded to adjacent carbon atoms of the aromatic ring.) 【Chemistry 2】 (In the formula, R A are each independently a hydrogen atom or a methyl group. R B are each independently a hydrogen atom or Z 6 may be bonded to form a ring. X 1 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-X 11 - is. X 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. Z 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -O-Z 11 -, -C(=O)-O-Z 11 - or -C(=O)-NH-Z 11 - is. Z 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O- or -Z 31 -O-. Z 31 represents a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, a nitro group, a cyano group, an ester bond, an ether bond, a urethane bond, a fluorine atom, an iodine atom, or a bromine atom. Z 4 is a single bond, a methylene group, or an ethylene group. Z 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a methylphenylene group, a dimethylphenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 - is. Z 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a methylphenylene group, a dimethylphenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a hydroxy group, or a halogen atom. Z 6 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. Z 7A represents a single bond or a divalent organic group having 1 to 24 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. Z 7B is a monovalent organic group having 1 to 10 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. Z 8 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. Z 9 is a trivalent organic group having 1 to 12 carbon atoms, which may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. 1 Reach and Rf 2 may combine to form a carbonyl group. R 21 and R 22 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. R 23 is a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. The circle R is an (a+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. a is 0, 1, 2, 3, 4 or 5. X - is a non-nucleophilic counterion. M + is a sulfonium cation or an iodonium cation.

2. 2. The resist composition according to claim 1, wherein the carboxyl group-containing polymer does not contain an acid labile group.

3. A laminate comprising a substrate and a resist film formed on the substrate from the resist composition according to claim 1 or 2.

4. The laminate according to claim 3 , further comprising a resist underlayer film between the substrate and the resist film.

5. 4. The laminate according to claim 3, wherein the resist film is formed by ligand exchange between the hypervalent iodine compound and a carboxy group-containing polymer.

6. 3. A pattern forming method comprising the steps of: forming a resist film on a substrate or a substrate having an underlayer film laminated thereon using the resist composition according to claim 1; exposing the resist film to i-line, KrF excimer laser, ArF excimer laser, electron beam, or extreme ultraviolet light; and developing the exposed resist film using a developer.

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