Resist composition and pattern forming method

Abstract

A non-chemically amplified resist composition that is excellent in sensitivity and limiting resolution in photolithography using high-energy rays, and a pattern formation method that uses the resist composition are provided. [Solution] A resist composition comprising a hypervalent iodine compound of a specific structure, a carboxylic acid derivative compound, and a solvent, wherein the carboxylic acid derivative compound is a carboxylic acid derivative compound represented by formula (5) or a polymer containing a carboxylic acid derivative repeating unit represented by formula (6). TIFF2026037546000178.tif35104

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 inventors of the present invention have discovered that a resist composition containing as its main components a specific hypervalent iodine compound and a carboxylic acid derivative compound provides a resist film that exhibits low roughness and high 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 carboxylic acid derivative compound, and a solvent: The resist composition, wherein the carboxylic acid derivative compound is a carboxylic acid derivative compound represented by the following formula (5) or a polymer containing a carboxylic acid derivative repeating unit represented by the following formula (6): [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. n7 is 0, 1, 2, 3, or 4, and 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. 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 R 13may 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 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 25 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, some of the -CH2- of the (n6)-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 22 may be the same or different. 22 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 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] (wherein p is 1, 2, 3 or 4. R 21 is a p-valent hydrocarbon group having 1 to 40 carbon atoms or a p-valent heterocyclic group having 2 to 40 carbon atoms, and when p is 2, R6 may be an ether bond, a carbonyl group, an azo group, a thioether bond, a carbonate bond, a carbamate bond, a sulfinyl group, or a sulfonyl group. Some or all of the hydrogen atoms of the p-valent hydrocarbon group or p-valent heterocyclic group may be substituted with a group containing a heteroatom, and some of the -CH2- groups of the p-valent hydrocarbon group may be substituted with a group containing a heteroatom. R 22 is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms, and some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing a hetero atom, or some of the -CH2- of the hydrocarbylene group may be substituted with a group containing a hetero atom. When p is 2, 3, or 4, each R 22 may be the same as or different from each other. R 23 ~R 26 are each independently a halogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. 23 and R 24 may be bonded to each other to form a ring together with the carbon atom and oxygen atom to which they are attached, and R 25 and R 26 may be bonded to each other to form a ring together with the carbon atom and oxygen atom to which they are attached. R A is a hydrogen atom, a halogen atom, a methyl group, or a trifluoromethyl group. X A is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OX A1 -X A1 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. 2. The resist composition of 1, wherein the polymer containing a carboxylic acid derivative repeating unit does not contain any acid labile group-containing repeating units other than the repeating unit represented by formula (6). 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 compound. 6. A pattern forming method comprising the steps of: forming a resist film on a substrate, or on an underlayer film of a substrate laminated with an underlayer film, using the resist composition of 1 or 2; exposing the resist film to i-line, KrF excimer laser, ArF excimer laser, EB, or EUV; 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 excellent roughness 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 carboxylic acid derivative compound 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.

[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] R 1 ~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 8The 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 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 12may 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 bonded.

[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 1 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 1 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 n7-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. 21 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]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka]

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[0044] [ka]

[0045] [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]

[0051] [ka]

[0052] [ka]

[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]

[0056] [ka]

[0057] [ka]

[0058] [ka]

[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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[0114] [Kuramanic acid derivative compound] The carboxylic acid derivative compound is a carboxylic acid derivative compound represented by the following formula (5) or a polymer containing a carboxylic acid derivative repeating unit represented by the following formula (6) (hereinafter also referred to as a carboxylic acid derivative-containing polymer). [ka]

[0115] In formula (5), p is 1, 2, 3 or 4.

[0116] In formula (5), R 21 is a p-valent hydrocarbon group having 1 to 40 carbon atoms or a p-valent heterocyclic group having 2 to 40 carbon atoms, and when p is 2, R 21 may be an ether bond, a carbonyl group, an azo group, a thioether bond, a carbonate bond, a carbamate bond, a sulfinyl group, or a sulfonyl group. Some or all of the hydrogen atoms of the p-valent hydrocarbon group or p-valent heterocyclic group may be substituted with a group containing a heteroatom, and some of the -CH2- groups of the p-valent hydrocarbon group may be substituted with a group containing a heteroatom.

[0117] R 21 The p-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 p 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.

[0118] 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.

[0119] Specific examples of the alkenes having 1 to 40 carbon atoms include ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, and structural isomers thereof.

[0120] Specific examples of the alkyne having 1 to 40 carbon atoms include acetylene, propyne, butyne, pentyne, hexyne, heptyne, octyne, nonyne, decyne, and structural isomers thereof.

[0121] Specific examples of the cyclic saturated hydrocarbon having 3 to 40 carbon atoms include cyclopropane, cyclobutane, cyclohexane, cycloheptane, cyclooctane, adamantane, and norbornane.

[0122] Specific examples of the cyclic unsaturated hydrocarbon having 3 to 40 carbon atoms include cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, and norbornene.

[0123] Specific examples of the aromatic hydrocarbon having 6 to 40 carbon atoms include benzene, naphthalene, and biphenyl.

[0124] R 21 The p-valent heterocyclic group represented by the following formula is a group obtained by eliminating n8 hydrogen atoms from a heterocyclic compound. Specific examples of the heterocyclic compound include furan, pyridine, pyrazole, and thiazolidine.

[0125] The p-valent hydrocarbon group or p-valent heterocyclic group 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. The n8-valent hydrocarbon group may have some of its -CH2- groups 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.

[0126] In formula (5), R 22 is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms, and some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing a hetero atom, or some of the -CH2- of the hydrocarbylene group may be substituted with a group containing a hetero atom. When p is 2, 3, or 4, each R 22 may be the same as or different from each other.

[0127] R 22The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, a dodecane-1,1 alkanediyl groups having 1 to 20 carbon atoms, such as a 2-diyl group; cyclic saturated hydrocarbylene groups having 3 to 20 carbon atoms, such as a cyclopentanediyl group, a cyclohexanediyl group, a norbornanediyl group, and an adamantanediyl group; unsaturated aliphatic hydrocarbylene groups having 2 to 20 carbon atoms, such as a vinylene group and a propene-1,3-diyl group; arylene groups having 6 to 20 carbon atoms, such as a phenylene group and 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, or some of the -CH- constituting the hydrocarbylene 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 hydrocarbylene group may contain a hydroxy group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a carbamate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride or the like.

[0128] In formula (6), R A is a hydrogen atom, a halogen atom, a methyl group, or a trifluoromethyl group. A is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OX A1 -X A1 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.

[0129] In formulas (5) and (6), R 23 ~R 26 are each independently a halogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, and R 23 and R 24 may be bonded to each other to form a ring together with the carbon atom and oxygen atom to which they are attached, and R 25 and R 26 may be bonded to each other to form a ring together with the carbon atom and oxygen atom to which they are attached.

[0130] R 23 ~R 26 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.

[0131] R 23 ~R 26 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 ]decanyl 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.

[0132] As the carboxylic acid compound represented by formula (5), those in which p is 2, 3 or 4 are preferred.

[0133] Specific examples of the carboxylic acid derivative compound represented by formula (5) include, but are not limited to, the compounds shown below. B is a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, tert-pentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo[5.2.1.0 2,6 ]decanyl group, adamantyl group, adamantylmethyl group, phenyl group, naphthyl group, anthracenyl group, or a group represented by any one of the following formulae (AL-1) to (AL-9). [ka] (In the formula, * represents a bond.)

[0134]

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[0168] [ka]

[0169] [ka]

[0170] [ka]

[0171] [ka]

[0172] [ka]

[0173] Specific examples of the carboxylic acid derivative-containing repeating unit represented by formula (6) include, but are not limited to, those shown below. A and R B is the same as above. [ka]

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] [ka]

[0178] [ka]

[0179] The carboxylic acid derivative-containing polymer may further contain a repeating unit other than the repeating unit represented by formula (6) (hereinafter also referred to as "other repeating units") The other repeating units are not particularly limited, but are preferably repeating units having a cyclic structure with a rigid skeleton and expected to have high etching resistance, or repeating units having a styrene skeleton.

[0180] 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]

[0181] [ka]

[0182] [ka]

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[0209] [ka]

[0210] In the carboxylic acid derivative-containing polymer, the molar ratio of the repeating unit represented by formula (6) to the other repeating units is preferably 10:90 to 90:10, more preferably 15:85 to 85:15, and even more preferably 20:80 to 80:20.

[0211] The weight average molecular weight (Mw) of the carboxylic acid derivative-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.

[0212] Furthermore, if the carboxylic acid derivative-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 carboxylic acid derivative-containing polymer have a narrow Mw / Mn distribution of 1.0 to 2.0.

[0213] The carboxylic acid derivative-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.

[0214] 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 the polymerization initiator 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.

[0215] 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 the chain transfer agent added is preferably 0.01 to 20 mol % of the total amount of monomers to be polymerized.

[0216] 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.

[0217] In the resist composition of the present invention, the molar ratio of the hypervalent iodine compound to the carboxylic acid derivative compound (when the carboxylic acid derivative compound is a carboxylic acid derivative-containing polymer, the molar ratio of the hypervalent iodine compound to the carboxylic acid derivative repeating units in the polymer) is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, and even more preferably 30:70 to 70:30. The hypervalent iodine compound may be used alone, or two or more compounds having different composition ratios, Mw, and / or Mw / Mn may be used in combination. The carboxylic acid derivative compound may be used alone, or two or more compounds having different composition ratios, Mw, and / or Mw / Mn may be used in combination.

[0218] [solvent] The resist composition contains a solvent. The solvent is not particularly limited as long as it can dissolve the hypervalent iodine compound, the carboxylic acid derivative compound, 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.

[0219] 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.

[0220] [Other ingredients] 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.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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.

[0227] 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.

[0228] 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.

[0229] 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.

[0230] When the resist composition of the present invention contains the photopolymerization initiator, its content is preferably 0.1 to 10 mass % of the total solid content, more preferably 0.1 to 5 mass %, and most preferably 0.1 to 1 mass %. When it is 0.1 mass % or more, a sufficient blending effect can be obtained.

[0231] As described above, the resist composition of the present invention contains a hypervalent iodine compound and a carboxylic acid derivative compound as main components, and can form a positive-tone pattern in which the exposed portions are soluble in a developer, or a negative-tone pattern in which the exposed portions are insoluble in a developer, particularly by EB or EUV exposure. The mechanism behind this is not completely clear, but is presumed to be as follows, for example.

[0232] The carboxylic acid derivative compound described above undergoes thermal decomposition of the carboxylic acid derivative moiety into a carboxylic acid during pre-baking after the formation of a resist film. The hypervalent iodine compounds represented by formulas (1), (2), (3), or (4) are tricoordinate compounds having an aryl group and a carboxylate ligand. When such tricoordinate iodine compounds are mixed with a carboxylic acid compound, an exchange of the carboxylate ligand is thought to occur through 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 is mixed with the carboxylic acid derivative compound, and the carboxylic acid derivative moiety is thermally decomposed into a carboxylic acid during the pre-baking process. The low-boiling acetic acid produced by the ligand exchange reaction between the carboxylic acid compound and the hypervalent iodine compound is then removed, completing the ligand exchange. The carboxylic acid compound then becomes a crosslinked polymer via the hypervalent iodine compound.

[0233] When a resist solution is prepared by directly adding a carboxylic acid compound and a hypervalent iodine compound to a solvent, the carboxylic acid compound has low solubility in the solvent and is insoluble in general-purpose solvents, so a carboxyl group-containing solvent is required. Therefore, it is believed that the use of a carboxylic acid derivative compound in which the carboxylic acid compound is protected with an organic group will make the resist solution soluble in general-purpose solvents. Furthermore, it is believed that the use of a carboxylic acid derivative compound can prevent aggregation of carboxyl groups in the film compared to the direct use of a carboxylic acid compound, improving the uniformity of the components after film formation and reducing roughness during patterning.

[0234] 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 and therefore cannot be prepared as solutions. This is presumably because hypervalent iodine compounds, which have low solvent solubility due to their inherent high polarization, become even less soluble when a carboxylic acid compound is used as a ligand. Therefore, it is desirable to react a carboxylic acid derivative compound with a carboxylic acid compound during film formation and the subsequent bake process, thereby removing the original low-molecular-weight carboxylic acid component and completing the ligand exchange reaction and forming a resist film.

[0235] When the carboxylic acid derivative compound is converted into a carboxylic acid compound by heat, the baking temperature can be adjusted depending on the type of organic group protecting the carboxylic acid.

[0236] The resist composition may further contain an acid generator. Acid generators include those that generate acid by thermal decomposition (thermal acid generators) and those that generate acid by light irradiation (photoacid generators), and either can be used. Specific examples of the acid generator include those described in paragraphs

[0061] to

[0085] of JP 2007-199653 A. The acid generator generates acid by heat or light, which reacts with a carboxylic acid derivative compound and converts the carboxylic acid derivative moiety into a carboxylic acid. The presence of the acid generator allows the reaction to generate a carboxylic acid to be completed at a lower temperature than when the reaction to convert a carboxylic acid is performed using heat alone, thereby achieving the effect of lowering the process temperature.

[0237] When the acid generator is a thermal acid generator, an acid is generated from the thermal acid generator during pre-baking after application of the resist composition, and the carboxylic acid derivative compound is reacted to form a carboxylic acid.

[0238] When the acid generator is a photoacid generator, the resist film is exposed to light after pre-baking following application of the resist composition, generating an acid from the photoacid generator and reacting the carboxylic acid derivative compound to form a carboxylic acid. In this case, the resist film is baked after the exposure to light to induce a ligand exchange reaction between the hypervalent iodine compound and the carboxylic acid compound in the resist film.

[0239] When the resist composition of the present invention contains an acid generator, the content thereof is preferably 0.05 to 20 parts by mass, and more preferably 0.1 to 100 parts by mass, relative to 100 parts by mass of the carboxylic acid derivative-containing compound. The acid generators may be used alone or in combination of two or more.

[0240] 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.

[0241] The resist composition of the present invention can be either positive-working or negative-working depending on the selection of components. In the case of a positive-working resist composition, the polymer contains a hypervalent iodine compound bonded to it during film formation. This polymer is decomposed by light to form a monovalent iodine compound, and at the same time, the bond between the carboxyl group-containing compound and the hypervalent iodine compound is released, resulting in a decrease in molecular weight. It is believed that this results in the formation of a positive-working pattern in which the exposed areas are removed by an organic solvent.

[0242] On the other hand, negative-tone patterns contain polymers crosslinked by hypervalent iodine compounds generated during film formation. When these polymers are decomposed by light, crosslinks or re-crosslinking of bonds occurs, resulting in an increase in molecular weight and a change in polarity. As a result, it is presumed that a negative-tone pattern is formed in which the unexposed areas are removed by an alkaline aqueous solution.

[0243] The hypervalent iodine compound preferably has a rigid skeleton with a large enough molecular weight that it hardly volatilizes even under vacuum conditions during EB or EUV exposure. When hypervalent iodine with a small molecular weight is used, the compound decomposed by exposure volatilizes under vacuum, causing significant exposure shrinkage of the resist film, contamination of the exposure machine by volatile components, and dimensional changes due to shrinkage of the resist pattern. Therefore, the use of a hypervalent iodine compound with a rigid skeleton with a large enough molecular weight that it hardly volatilizes can solve the above-mentioned problems. Furthermore, the use of a hypervalent iodine compound with a large molecular weight and a rigid skeleton improves the glass transition temperature of the pattern, prevents pattern distortion, improves resolution, and improves etching resistance.

[0244] The hypervalent iodine compound preferably has a plurality of hypervalent iodine bonds in one molecule, which increases the crosslink density of the pattern in both positive and negative tones, thereby preventing distortion of the pattern and enabling the formation of a pattern with high etching resistance and excellent resolution.

[0245] Based on the above speculation, it can be said that the resist composition of the present invention is a non-chemically amplified resist composition. The resist composition of the present invention contains a carboxylic acid derivative compound in which a carboxy group is substituted with an acid labile group, but the acid labile group is released during baking before patterned exposure, and a reaction in which the acid labile group is released does not occur during patterned exposure. In contrast, in conventional chemically amplified resist compositions, the acid labile group is released during patterned exposure and subsequent baking, so the resist composition of the present invention is free from adverse effects due to acid diffusion (e.g., image blurring) and can resolve fine patterns.

[0246] 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.

[0247] 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 presence 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 issues with solubility in solvents. Furthermore, the resist composition of the present invention can be applied to both positive-tone and negative-tone resists, thereby offering a wide range of uses. For example, in the contact hole formation process, metal resists developed using negative-tone development require a reversal process step after pillar pattern formation, whereas positive-tone 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.

[0248] 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, these patent documents only describe the properties of the resist compositions as being able to improve line edge roughness, and make no mention 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, these patent documents do not suggest a material that can reduce shot noise in EUV lithography and that can 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 clearly provides a novel resist composition and pattern formation method.

[0249] [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.

[0250] First, the resist composition of the present invention is applied to a substrate for integrated circuit production, or to an underlayer film of a substrate for integrated circuit production (e.g., Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coating), or to a substrate for mask circuit production, or to an underlayer film of a substrate for mask circuit production (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 250°C for 10 seconds to 30 minutes, more preferably at 80 to 220°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.

[0251] 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 2When 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.

[0252] 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.

[0253] 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.

[0254] After development, rinsing is performed as necessary. A preferred rinsing solution is a solvent that is miscible with the developer but does not dissolve the resist film. Preferred examples of such solvents include alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms.

[0255] 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]

[0256] 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.

[0257] [1] Synthesis of carboxylic acid derivative compounds [Synthesis Example 1-1] Synthesis of carboxylic acid derivative compound m-1 [ka]

[0258] 4.2 g of 1,3,5-benzenetricarboxylic acid, 7.9 g of triethylamine, and 60 g of methylene chloride were placed in a 200 mL flask and stirred in an ice bath. 9.6 g of 1-chloro-1-methoxy-2-methylpropane was added dropwise, and the mixture was stirred at room temperature for 8 hours. 60 mL of water was then added. The organic layer was extracted, washed twice with 30 mL of water, and concentrated at 40°C to obtain the target compound m-1 as an oil (yield: 18 g, 86%). Nuclear magnetic resonance spectrum of compound m-1 ( 1 The results of H-NMR / DMSO-d6) are shown below. 1 H-NMR (500 MHz, DMSO-d6) δ 0.95(d, 18H), 3.41(s, 9H), 4.92(m, 3H), 5.82(s, 3H), 8.78(s, 3H).

[0259] [Synthesis Examples 1-2 to 1-6] Synthesis of carboxylic acid derivative compounds m-2 to m-6 Compounds m-2 to m-6 were synthesized in the same manner as in Synthesis Example 1-1, except that the types of raw material compounds were changed. [ka]

[0260] [2] Synthesis of polymers containing carboxylic acid derivatives The monomers used in the synthesis of the carboxylic acid derivative-containing polymers P-1 to P-10 are as follows. [ka]

[0261] [ka]

[0262] [ka]

[0263] [Synthesis Example 2-1] Synthesis of Polymer P-1 A monomer-polymerization initiator solution was prepared by placing 70 g of monomer a-1, 11 g of monomer b-1, 4.6 g of V-601 (Fujifilm Wako Pure Chemical Industries, Ltd.), and 124 g of MEK in a flask under a nitrogen atmosphere. 62 g of MEK was placed in 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. 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: 78 g, 98%). The Mw of polymer P-1 was 8,000, and the Mw / Mn ratio was 1.44. The Mw is a polystyrene-equivalent value measured by GPC using THF as a solvent. [ka]

[0264] [Synthesis Examples 2-2 to 2-10] Synthesis of Polymers P-2 to P-10 The polymers shown in Table 1 below were synthesized in the same manner as in Synthesis Example 2-1, except that the types and blending ratios of the monomers were changed.

[0265] [Table 1]

[0266] [3] Preparation of resist composition [Examples 1-1 to 1-20, Comparative Examples 1-1 to 1-4] Resist compositions (R-01 to R-20, CR-01, and CR-02) were prepared by dissolving a hypervalent iodine compound, a carboxylic acid derivative or compound, and a photoacid generator in a solvent containing 0.01% by mass of a surfactant (PF-636, Omnova) in the compositions shown in Table 2 below, and filtering the resulting solution through a 0.2 μm Teflon® filter. Resist compositions (CR-03 and CR-04) were prepared by dissolving a polymer, a photoacid generator, and a sensitivity adjuster in a solvent containing 0.01% by mass of a surfactant (PF-636, Omnova) in the compositions shown in Table 3 below, and filtering the resulting solution through a 0.2 μm Teflon® filter.

[0267] [Table 2]

[0268] [Table 3]

[0269] In Tables 2 and 3, the hypervalent iodine compounds I-1 to I-3, carboxylic acid compound d-1, thermal acid generators TAG-1 to TAG-3, photoacid generator PAG-1, sensitivity adjuster Q-1, and solvents are as follows. [ka]

[0270] [ka]

[0271] [ka]

[0272] [ka]

[0273] [ka]

[0274] Solvent: PGMEA (propylene glycol monomethyl ether acetate) AcOH (acetic acid) GBL (γ-butyrolactone)

[0275] When the carboxylic acid derivative compounds of Examples 1-1 to 1-20 were used, they dissolved only in PGMEA, whereas when the carboxylic acid compounds of Comparative Examples 1-1 and 1-2 were used, they did not dissolve unless acetic acid was added. This shows that protecting the carboxylic acid to form a carboxylic acid derivative makes it soluble in general-purpose solvents.

[0276] [4] EUV lithography evaluation (line and space patterns) [Examples 2-1 to 2-20, Comparative Examples 2-1 to 2-4] Each resist composition (R-01 to R-20, CR-01 to CR-04) was spin-coated onto a Si substrate coated 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 prebaked (PAB) for 60 seconds at the temperature listed in Table 4 to produce a 40 nm thick resist film. The resist film was exposed to a 36 nm line-and-space (LS) 1:1 pattern using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9, 90-degree dipole illumination), followed by PEB for 60 seconds on a hot plate at the temperature listed in Table 4. Development was then performed for 30 seconds using the developer listed in Table 4 to form an LS pattern with a space width of 18 nm and a pitch of 36 nm.

[0277] The resulting resist patterns were evaluated as follows, and the results are shown in Table 4.

[0278] [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.

[0279] [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.

[0280] [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.

[0281] [Table 4]

[0282] Developer: nBA (butyl acetate) TMAH (2.38% by mass tetramethylammonium hydroxide aqueous solution)

[0283] From the results shown in Table 4, comparing Examples 2-1 to 2-3 with Examples 2-4 to 2-6, it was found that the addition of a thermal acid generator allowed the carboxylic acid derivative compound to react with a carboxylic acid at a low pre-bake temperature, thereby enabling pattern formation. Furthermore, comparing Examples 2-17 to 2-20, it was found that the pre-bake temperature could be adjusted depending on the type of substituent on the carboxylic acid derivative. Furthermore, comparing Examples 2-1 to 2-20 with Comparative Examples 2-1 to 2-2, it was found that the use of a carboxylic acid derivative allowed the formation of a resist pattern with excellent LWR. Furthermore, it was found that the sensitivity, resolution, and LWR were excellent, even when compared to Comparative Examples 2-3 and 2-4, which were chemically amplified resist compositions using an acid-catalyzed reaction.

[0284] [5] EUV lithography evaluation (contact hole pattern) [Examples 3-1 to 3-20, Comparative Examples 3-1 to 3-4] Each resist composition (R-01 to R-20, CR-01 to CR-04) 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.

[0285] The resulting resist patterns were evaluated as follows, and the results are shown in Table 5.

[0286] [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 22 nm was determined. 2) was calculated and used as the sensitivity.

[0287] [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 obtained.

[0288] [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.

[0289] [Table 5]

[0290] From the results shown in Table 5, comparing Examples 3-1 to 3-3 with Examples 3-4 to 3-6, it was found that the addition of a thermal acid generator allowed the carboxylic acid derivative compound to react with a carboxylic acid at a low pre-bake temperature, thereby enabling pattern formation. Furthermore, comparing Examples 3-17 to 3-20, it was found that the pre-bake temperature could be adjusted depending on the type of substituent on the carboxylic acid derivative. Furthermore, comparing Examples 3-1 to 3-20 with Comparative Examples 3-1 and 3-2, it was found that the use of a carboxylic acid derivative allowed the formation of a resist pattern with excellent LWR. Furthermore, it was found that the sensitivity, resolution, and CDU were superior, even when compared to Comparative Examples 3-3 and 3-4, which were chemically amplified resist compositions using an acid-catalyzed reaction.

Claims

1. A resist composition comprising at least one hypervalent iodine compound represented by any one of the following formulas (1) to (4), a carboxylic acid derivative compound, and a solvent: The resist composition wherein the carboxylic acid derivative compound is a carboxylic acid derivative compound represented by the following formula (5) or a polymer containing a carboxylic acid derivative repeating unit represented by the following formula (6): 【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. n7 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. 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 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 25 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 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 22 may be the same or different. 22 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 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】 (wherein p is 1, 2, 3 or 4. R 21 is a p-valent hydrocarbon group having 1 to 40 carbon atoms or a p-valent heterocyclic group having 2 to 40 carbon atoms, and when p is 2, R ６ may be an ether bond, a carbonyl group, an azo group, a thioether bond, a carbonate bond, a carbamate bond, a sulfinyl group, or a sulfonyl group. In addition, some or all of the hydrogen atoms of the p-valent hydrocarbon group or the p-valent heterocyclic group may be substituted with a group containing a hetero atom, and the -CH 2 A portion of - may be substituted with a group containing a hetero atom. R 22 represents a single bond or a hydrocarbylene group having 1 to 10 carbon atoms, and some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing a hetero atom, and the —CH 2 When p is 2, 3, or 4, each R 22 may be the same as or different from each other. R 23 ~R 26 are each independently a halogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. 23 and R 24 may be bonded to each other to form a ring together with the carbon atom and oxygen atom to which they are attached, and R 25 and R 26 may be bonded to each other to form a ring together with the carbon atom and oxygen atom to which they are attached. R A is a hydrogen atom, a halogen atom, a methyl group, or a trifluoromethyl group. X A represents a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-X A1 - is. X A1 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.

2. 2. The resist composition according to claim 1, wherein the polymer containing the carboxylic acid derivative repeating unit does not contain any acid labile group-containing repeating units other than the repeating unit represented by formula (6).

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 compound.

6. 3. A pattern forming method comprising the steps of: forming a resist film on a substrate, or on an underlayer film of 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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