Chemically amplified positive resist material and pattern formation method

Abstract

To provide a positive type resist material having sensitivity and resolution superior to those of a conventional positive type resist material, having small LER or LWR, excellent in CDU, and having an excellent pattern shape after exposure; and to provide a pattern formation method.SOLUTION: A positive type resist material contains a base polymer containing at least one selected from a repeating unit a having an ammonium salt structure of sulfonamide having an aromatic ring substituted by an iodine atom, a repeating unit b1 in which a hydrogen atom in a carboxy group is substituted by an acid-unstable group, and a repeating unit b2 in which a hydrogen atom in a phenolic hydroxy group is substituted by an acid-unstable group.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] As LSIs become more highly integrated and faster, pattern rules are becoming finer at a rapid pace. In particular, logic devices used in smartphones and other devices are driving this miniaturization, and 10-nm-node logic devices are being mass-produced using the multiple-exposure (multi-patterning lithography) process with ArF lithography. For the next 7-nm and 5-nm-node lithography, problems such as high costs due to multiple exposures and problems with overlay accuracy in multiple exposures are becoming apparent, and the arrival of extreme ultraviolet (EUV) lithography, which can reduce the number of exposures, is anticipated.

[0003] EUV light, with a wavelength of 13.5 nm, is less than 1 / 10 the wavelength of ArF excimer laser light, with a wavelength of 193 nm, so it is expected to produce high light contrast and high resolution. EUV has a short wavelength and high energy density, so the acid generator is exposed to a small number of photons. The number of photons in EUV exposure is said to be 1 / 14 of that in ArF excimer laser exposure. With EUV exposure, the phenomenon in which variation in photons causes degradation of line edge roughness (LER, LWR) and hole dimension uniformity (CDU) is viewed as a problem.

[0004] In order to reduce the variation in photons, it has been proposed to increase the light absorption of the resist film to increase the number of photons absorbed in the resist film. For example, among halogen atoms, iodine atoms have a particularly high absorption rate for EUV with a wavelength of 13.5 nm, and therefore, in recent years, it has been proposed to use a polymer having iodine atoms as an EUV resist material (Patent Documents 1 to 3). When using a polymer having iodine atoms as described in Patent Documents 1 to 3, it is expected that the increase in the absorption of EUV increases the number of photons absorbed in the film, and at the same time, the amount of acid generated increases, the sensitivity increases, and the LER, LWR, and CDU decrease. However, in reality, the solubility of the polymer having iodine atoms in an alkaline aqueous solution, which is a developing solution, is extremely low, so the dissolution contrast decreases and the LER, LWR, and CDU deteriorate. There is a demand for a resist material with high light absorption and dissolution contrast.

[0005] In order to suppress acid diffusion, resist materials using polymers containing repeating units having amino groups have been proposed (Patent Documents 4 and 5). Polymeric amines are characterized by their high effect of suppressing acid diffusion, but have the problem of low sensitivity. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-161823 A [Patent Document 2] International Publication No. 2013 / 024777 [Patent Document 3] JP 2018-4812 A [Patent Document 4] JP 2008-133312 A [Patent Document 5] JP 2009-181062 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a positive resist material and a pattern formation method which have sensitivity and resolution superior to conventional positive resist materials, small LER and LWR, excellent CDU, and a good pattern shape after exposure. [Means for solving the problem]

[0008] The present inventors have conducted intensive research to obtain a positive resist material that has the high sensitivity and resolution, small LER and LWR, and excellent CDU required in recent years, and as a result, have found that it is necessary to shorten the acid diffusion distance to the utmost, and that at the same time, a problem occurs in that the sensitivity decreases and at the same time the resolution of two-dimensional patterns such as hole patterns decreases due to a decrease in dissolution contrast. However, by using a polymer containing a repeating unit having an ammonium salt structure of a sulfonamide having an aromatic ring substituted with an iodine atom as the base polymer, the sulfonamide having an aromatic ring substituted with an iodine atom dissolves in an alkaline developer, and the iodine atoms bonded to the base polymer disappear, so that a decrease in the dissolution rate in the alkaline developer does not occur. In addition, the number of absorbed photons can be increased due to the strong absorption of iodine atoms during exposure, and while the efficiency of generation of acid generated from the acid generator is increased, the acid diffusion distance can be minimized at the same time. The present inventors have found that this is particularly effective when used as the base polymer of a chemically amplified positive resist material.

[0009] Furthermore, it has been found that by introducing into the base polymer a repeating unit in which the hydrogen atom of a carboxy group or a phenolic hydroxy group is substituted with an acid labile group in order to improve the dissolution contrast, a positive resist material can be obtained which has high sensitivity, a significantly high dissolution rate contrast in an alkaline developer before and after exposure, high sensitivity, a high effect of suppressing acid diffusion, high resolution, improved LER, LWR and CDU, and a good pattern shape after exposure, and is particularly suitable as a fine pattern forming material for the manufacture of VLSIs or photomasks, and has been completed according to this finding.

[0010] That is, the present invention provides the following positive resist material and pattern forming method. 1. A positive resist material comprising a base polymer containing a repeating unit a having an ammonium salt structure of a sulfonamide having an aromatic ring substituted with an iodine atom, and at least one repeating unit selected from a repeating unit b1 in which the hydrogen atom of a carboxy group is substituted with an acid labile group and a repeating unit b2 in which the hydrogen atom of a phenolic hydroxy group is substituted with an acid labile group. 2. A positive resist material according to claim 1, wherein the repeating unit a is represented by the following formula (a): [ka] (In the formula, m is an integer of 1 to 5. n is an integer of 0 to 3, provided that 1≦m+n≦5. p is 1 or 2. q is 1 or 2. R A is a hydrogen atom or a methyl group. X 1A is a single bond, an ester bond or an amide bond. X 1B is a single bond or a (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may contain an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone group, a lactam group, a carbonate bond, a halogen atom, a hydroxy group, or a carboxy group. R 1 , R 2 and R 3 are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms; and R 1 and R 2 or R 1 and X 1B may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and the ring may contain an oxygen atom, a sulfur atom, a nitrogen atom or a double bond. R 4is a hydroxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 7 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxycarbonyl group having 2 to 7 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms which may be substituted with a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, -N(R 4A )-C(=O)-R 4B Or -N(R 4A )-C(=O)-OR 4B R 4A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 4B is a saturated hydrocarbyl group having 1 to 6 carbon atoms, an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms. R 5 is a (q+1)-valent hydrocarbon group having 1 to 10 carbon atoms. R 6 is a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms or a fluorinated aryl group having 6 to 10 carbon atoms. L 1 is a single bond, an ether bond, a carbonyl group, an ester bond, an amide bond, a carbonate bond, or a hydrocarbylene group having 1 to 20 carbon atoms, and the hydrocarbylene group may contain an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, or a carboxy group. 3. A positive resist material according to 1 or 2, wherein the repeating unit b1 is represented by the following formula (b1), and the repeating unit b2 is represented by the following formula (b2): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1is a linking group having 1 to 12 carbon atoms and containing at least one type selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 is an acid labile group. R 13 represents a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 6 carbon atoms, a halogen atom, a nitro group, or a cyano group. R 14 represents a single bond or a saturated hydrocarbylene group having 1 to 6 carbon atoms, some of whose carbon atoms may be substituted with ether bonds or ester bonds. a is 1 or 2, and b is an integer from 0 to 4, provided that 1≦a+b≦5. 4. The positive resist material of any one of 1 to 3, wherein the base polymer further contains a repeating unit represented by any one of the following formulas (d1) to (d3): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. 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. 11represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group obtained by combining these and having 7 to 18 carbon atoms, 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-, -Z 31 -O- or -Z 31 -OC(=O)-. Z 31 represents a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group obtained by combining these and having 7 to 18 carbon atoms, and may contain a carbonyl group, an ester bond, an ether bond, a bromine atom, or an iodine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. Z 5 is a single bond, a methylene group, an ethylene group, a phenylene 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. 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene 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, or a hydroxy group. R 21 ~R 28 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 and R 24 or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. M - is a non-nucleophilic counterion. 5. A positive resist material according to any one of 1 to 4, further comprising an acid generator that generates a sulfonic acid, a sulfonimide or a sulfonmethide. 6. A positive resist material according to any one of 1 to 5, further comprising an organic solvent. 7. A positive resist material according to any one of 1 to 6, further comprising a dissolution inhibitor. 8. A positive resist material according to any one of 1 to 7, further comprising a surfactant. 9. A pattern forming method comprising the steps of forming a resist film on a substrate using a positive resist material according to any one of 1 to 8, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer. 10. The pattern formation method according to 9, wherein the high-energy radiation is ArF excimer laser light having a wavelength of 193 nm or KrF excimer laser light having a wavelength of 248 nm. 11. The pattern formation method according to 9, wherein the high energy beam is an electron beam (EB) or EUV having a wavelength of 3 to 15 nm. Effect of the Invention

[0011] The positive resist material of the present invention can increase the decomposition efficiency of the acid generator, and therefore has a high effect of suppressing the diffusion of acid, high sensitivity, high resolution, and good pattern shape after exposure, LER, LWR and CDU. Therefore, due to these excellent characteristics, it is extremely useful, and is particularly useful as a fine pattern forming material for photomasks for VLSI manufacturing or EB drawing, and a pattern forming material for EB or EUV lithography. The positive resist material of the present invention can be applied, for example, not only to lithography in semiconductor circuit formation, but also to the formation of mask circuit patterns, micromachines, and thin film magnetic head circuits. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] [Positive resist material] The positive resist material of the present invention is characterized in that it comprises a base polymer including a repeating unit a having an ammonium salt structure of a sulfonamide having an aromatic ring substituted with an iodine atom, and at least one selected from a repeating unit b1 in which the hydrogen atom of a carboxy group is substituted with an acid labile group, and a repeating unit b2 in which the hydrogen atom of a phenolic hydroxy group is substituted with an acid labile group.

[0013] [Base polymer] The repeating unit a is preferably one represented by the following formula (a). [ka]

[0014] In formula (a), m is an integer of 1 to 5. n is an integer of 0 to 3, provided that 1≦m+n≦5. p is 1 or 2. q is 1 or 2.

[0015] In formula (a), R A is a hydrogen atom or a methyl group. 1A is a single bond, an ester bond or an amide bond. 1B is a single bond or a (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may contain an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone group, a lactam group, a carbonate bond, a halogen atom, a hydroxy group, or a carboxy group.

[0016] X 1BThe (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (1) is a group obtained by eliminating (p+1) hydrogen atoms from an aliphatic hydrocarbon having 1 to 20 carbon atoms or an aromatic hydrocarbon having 6 to 20 carbon atoms, 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 propane-2,2-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, a butane-2,2-diyl group, a butane-2,3-diyl group, a 2-methylpropane-1,3-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 hexane-2,3-diyl group, a hexane-1,9-diyl group, a hexane-2,4-diyl group, a hexane-2,5-diyl group, a hexane-3,6-diyl group, a hexane-4,7-diyl group, a hexane-5,8-diyl group, a hexane-6,9-diyl group, a hexane-7,7-diyl group, a hexane-8,7-diyl group, a hexane-9,8-diyl group, a hexane-10,10-diyl group, a hexane-11,10-diyl group, a hexane-12,12-diyl group, a hexane-13,14-diyl group, a hexane-14,16-diyl group, a hexane-15,17-diyl group, a hexane-16,18-diyl group, alkanediyl groups such as 1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, and dodecane-1,12-diyl group; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group; arylene groups such as phenylene group and naphthylene group; groups obtained by combining these groups; and trivalent groups obtained by further eliminating one hydrogen atom from these groups.

[0017] In formula (a), R 1 , R 2 and R 3 are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms. 1 and R 2 or R 1 and X 1B may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and the ring may contain an oxygen atom, a sulfur atom, a nitrogen atom, or a double bond. In this case, the ring is preferably a ring having 3 to 12 carbon atoms.

[0018] R 1 , R 2 and R 3The alkyl group having 1 to 12 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, and an n-dodecyl group. 1 , R 2 and R 3 Examples of the alkenyl group having 2 to 12 carbon atoms represented by the formula (I) include a vinyl group, a 1-propenyl group, a 2-propenyl group, a butenyl group, and a hexenyl group. 1 , R 2 and R 3 Examples of the aryl group having 6 to 12 carbon atoms represented by the formula (1) include a phenyl group, a tolyl group, a xylyl group, a 1-naphthyl group, and a 2-naphthyl group. 1 , R 2 and R 3 Examples of the aralkyl group having 7 to 12 carbon atoms represented by the following formula include a benzyl group.

[0019] In formula (a), R 4 is a hydroxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 7 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxycarbonyl group having 2 to 7 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms which may be substituted with a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, -N(R 4A )-C(=O)-R 4B Or -N(R 4A )-C(=O)-OR 4B R 4A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 4B is a saturated hydrocarbyl group having 1 to 6 carbon atoms, an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms.

[0020] R 4 , R 4A and R 4B The saturated hydrocarbyl group having 1 to 6 carbon atoms represented by the formula (I) may be linear, branched or cyclic, and specific examples thereof include alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl and n-hexyl groups; and cycloalkyl groups having 3 to 6 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl groups. 4 Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group having 1 to 6 carbon atoms, the saturated hydrocarbylcarbonyloxy group having 2 to 7 carbon atoms, and the saturated hydrocarbyloxycarbonyl group having 2 to 7 carbon atoms represented by the following formula (I) include the same as the specific examples of the saturated hydrocarbyl groups described above, and examples of the saturated hydrocarbyl moiety of the saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms include those having 1 to 4 carbon atoms among the specific examples of the saturated hydrocarbyl groups described above.

[0021] R 4B The unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms represented by the formula (I) may be linear, branched or cyclic, and specific examples thereof include alkenyl groups having 2 to 8 carbon atoms, such as vinyl group, 1-propenyl group, 2-propenyl group, butenyl group and hexenyl group; and cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 8 carbon atoms, such as cyclohexenyl group. 4B Examples of the aryl group having 6 to 14 carbon atoms represented by the formula (R) include a phenyl group, a naphthyl group, and a fluorenyl group. 4B Examples of the aralkyl group having 7 to 15 carbon atoms represented by the formula (I) include a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, a fluorenylmethyl group, and a fluorenylethyl group.

[0022] Of these, R 4Examples of the alkyl group include a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group, a saturated hydrocarbyl group having 1 to 3 carbon atoms, a saturated hydrocarbyloxy group having 1 to 3 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 4 carbon atoms, and -N(R 4A )-C(=O)-R 4B Or -N(R 4A )-C(=O)-OR 4B is preferred.

[0023] In formula (a), R 5 is a (q+1)-valent hydrocarbon group having 1 to 10 carbon atoms. The (q+1)-valent hydrocarbon group is a group obtained by eliminating (q+1) hydrogen atoms from an aliphatic hydrocarbon having 1 to 10 carbon atoms or an aromatic hydrocarbon having 6 to 10 carbon atoms, 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 propane-2,2-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, a butane-2,2-diyl group, a butane-2,3-diyl group, a 2-methylpropane-1,3-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, and a heptane-1,7-diyl group. alkanediyl groups having 1 to 10 carbon atoms, such as octane-1,8-diyl group, nonane-1,9-diyl group, and decane-1,10-diyl group; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms, such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group; arylene groups having 6 to 10 carbon atoms, such as phenylene group and naphthylene group; groups obtained by combining these groups; and trivalent groups obtained by further eliminating one hydrogen atom from these groups.

[0024] In formula (a), R 6is a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms or a fluorinated aryl group having 6 to 10 carbon atoms. The fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms may be linear, branched or cyclic, and specific examples thereof include the above-mentioned saturated hydrocarbyl group having 1 to 6 carbon atoms in which some or all of the hydrogen atoms have been substituted with fluorine atoms. Examples of the fluorinated aryl group having 6 to 10 carbon atoms include groups in which some or all of the hydrogen atoms of an aryl group such as a phenyl group or a naphthyl group have been substituted with fluorine atoms; groups obtained by combining these groups, etc.

[0025] In formula (a), L 1 is a single bond, an ether bond, a carbonyl group, an ester bond, an amide bond, a carbonate bond, or a hydrocarbylene group having 1 to 20 carbon atoms. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbylene group may contain an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxyl group, or a carboxyl group.

[0026] Examples of the cation of the monomer that gives the repeating unit a include, but are not limited to, those shown below. A is the same as above. [ka]

[0027] [ka]

[0028] [ka]

[0029] [ka]

[0030] [ka]

[0031] Examples of the anion of the monomer that provides the repeating unit a include, but are not limited to, the following. [ka]

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] [ka]

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] The repeating unit a is a quencher having an ammonium salt structure of sulfonamide having an aromatic ring substituted with an iodine atom, and a polymer containing this is a quencher-bound polymer. Quencher-bound polymers have a high effect of suppressing acid diffusion, and as described above, have the characteristic of excellent resolution. At the same time, since the repeating unit a has a highly absorbent iodine atom, secondary electrons are generated during exposure, which promotes the decomposition of the acid generator, thereby increasing sensitivity. This makes it possible to simultaneously achieve high sensitivity, high resolution, low LWR, and low CDU.

[0041] Iodine atoms, which have a large atomic weight, are poorly soluble in alkaline developers, and when they are bonded to the polymer backbone, the solubility of the exposed area in the alkaline developer decreases, which not only reduces the resolution and sensitivity, but also causes defects. On the other hand, in the repeating unit a, the sulfonamide having an iodine atom forms a salt with an alkaline compound in the developer and leaves the polymer backbone. This ensures sufficient solubility in the alkaline developer, making it possible to suppress the occurrence of defects.

[0042] The monomer that gives the repeating unit a is a polymerizable ammonium salt monomer. The ammonium salt monomer can be obtained by a neutralization reaction between a monomer that is an amine compound having a structure in which one hydrogen atom bonded to the nitrogen atom of the cation moiety of the repeating unit is eliminated and a sulfonamide.

[0043] The repeating unit a is formed by carrying out a polymerization reaction using the ammonium salt monomer. Alternatively, the repeating unit a may be formed by synthesizing a polymer by carrying out a polymerization reaction using a monomer which is an amine compound, and then adding a sulfonamide to the resulting reaction solution or a solution containing a purified polymer to carry out a neutralization reaction.

[0044] Examples of the repeating units b1 and b2 include those represented by the following formulae (b1) and (b2), respectively. [ka]

[0045] In formulas (b1) and (b2), R A are each independently a hydrogen atom or a methyl group. Y 1 Y is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. 2 is a single bond or an ester bond. 3 R is a single bond, an ether bond or an ester bond. 11 and R 12 is an acid labile group. 13 R is a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 6 carbon atoms, a halogen atom, a nitro group, or a cyano group. 14 is a single bond or a saturated hydrocarbylene group having 1 to 6 carbon atoms, some of whose carbon atoms may be substituted with ether bonds or ester bonds. a is 1 or 2. b is an integer of 0 to 4, with the proviso that 1≦a+b≦5.

[0046] Examples of monomers that provide the repeating unit b1 include, but are not limited to, those shown below. A and R 11 is the same as above. [ka]

[0047] [ka]

[0048] Examples of monomers that provide the repeating unit b2 include, but are not limited to, those shown below.A and R 12 is the same as above. [ka]

[0049] [ka]

[0050] R 11 or R 12 The acid labile group represented by the formula (AL-1) may be selected from various groups, and examples thereof include those represented by the following formulae (AL-1) to (AL-3). [ka] (In the formula, the dashed lines represent bonds.)

[0051] In formula (AL-1), c is an integer of 0 to 6. L1 is a tertiary hydrocarbyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, a trihydrocarbylsilyl group in which each hydrocarbyl group is a saturated hydrocarbyl group having 1 to 6 carbon atoms, a carbonyl group, a saturated hydrocarbyl group having 4 to 20 carbon atoms containing an ether bond or an ester bond, or a group represented by formula (AL-3). The tertiary hydrocarbyl group means a group obtained by eliminating a hydrogen atom from a tertiary carbon atom of a hydrocarbon.

[0052] R L1The tertiary hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, branched or cyclic. Specific examples thereof include tert-butyl group, tert-pentyl group, 1,1-diethylpropyl group, 1-ethylcyclopentyl group, 1-butylcyclopentyl group, 1-ethylcyclohexyl group, 1-butylcyclohexyl group, 1-ethyl-2-cyclopentenyl group, 1-ethyl-2-cyclohexenyl group, and 2-methyl-2-adamantyl group. Examples of the trihydrocarbylsilyl group include trimethylsilyl group, triethylsilyl group, and dimethyl-tert-butylsilyl group. The saturated hydrocarbyl group containing a carbonyl group, an ether bond or an ester bond may be linear, branched or cyclic, but is preferably cyclic. Specific examples thereof include a 3-oxocyclohexyl group, a 4-methyl-2-oxooxan-4-yl group, a 5-methyl-2-oxooxolan-5-yl group, a 2-tetrahydropyranyl group and a 2-tetrahydrofuranyl group.

[0053] Examples of the acid labile group represented by formula (AL-1) include a tert-butoxycarbonyl group, a tert-butoxycarbonylmethyl group, a tert-pentyloxycarbonyl group, a tert-pentyloxycarbonylmethyl group, a 1,1-diethylpropyloxycarbonyl group, a 1,1-diethylpropyloxycarbonylmethyl group, a 1-ethylcyclopentyloxycarbonyl group, a 1-ethylcyclopentyloxycarbonylmethyl group, a 1-ethyl-2-cyclopentenyloxycarbonyl group, a 1-ethyl-2-cyclopentenyloxycarbonylmethyl group, a 1-ethoxyethoxycarbonylmethyl group, a 2-tetrahydropyranyloxycarbonylmethyl group, and a 2-tetrahydrofuranyloxycarbonylmethyl group.

[0054] Further, examples of the acid labile group represented by formula (AL-1) include groups represented by the following formulae (AL-1)-1 to (AL-1)-10. [ka] (In the formula, the dashed lines represent bonds.)

[0055] In formulae (AL-1)-1 to (AL-1)-10, c is the same as defined above. L8 R is each independently a saturated hydrocarbyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. L9 R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. L10 is a saturated hydrocarbyl group having 2 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic.

[0056] In formula (AL-2), R L2 and R L3 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10. The saturated hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, and an n-octyl group.

[0057] In formula (AL-2), R L4 is a hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10, which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples of the hydrocarbyl group include saturated hydrocarbyl groups having 1 to 18 carbon atoms, and some of the hydrogen atoms may be substituted with a hydroxy group, an alkoxy group, an oxo group, an amino group, an alkylamino group, or the like. Examples of such substituted saturated hydrocarbyl groups include those shown below. [ka] (In the formula, the dashed lines represent bonds.)

[0058] R L2 and R L3 And, R L2 and R L4 and, or R L3and R L4 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, or together with the carbon atom and the oxygen atom, in which case R L2 and R L3 , R L2 and R L4 , or R L3 and R L4 are each independently an alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10. The number of carbon atoms in the ring obtained by bonding these is preferably 3 to 10, more preferably 4 to 10.

[0059] Among the acid labile groups represented by formula (AL-2), linear or branched ones include, but are not limited to, those represented by the following formulae (AL-2)-1 to (AL-2)-69, in which the dashed lines represent bonds. [ka]

[0060] [ka]

[0061] [ka]

[0062] [ka]

[0063] Among the acid labile groups represented by formula (AL-2), examples of cyclic groups include a tetrahydrofuran-2-yl group, a 2-methyltetrahydrofuran-2-yl group, a tetrahydropyran-2-yl group, and a 2-methyltetrahydropyran-2-yl group.

[0064] Examples of the acid labile group include groups represented by the following formula (AL-2a) or (AL-2b): The base polymer may be inter- or intra-molecularly crosslinked by the acid labile group. [ka] (In the formula, the dashed lines represent bonds.)

[0065] In formula (AL-2a) or (AL-2b), R L11 and R L12 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 8 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. L11 and R L12 may be bonded to each other to form a ring together with the carbon atom to which they are attached, in which case R L11 and R L12 R is each independently an alkanediyl group having 1 to 8 carbon atoms. L13 are each independently a saturated hydrocarbylene group having 1 to 10 carbon atoms. The saturated hydrocarbylene group may be linear, branched, or cyclic. d and e are each independently an integer of 0 to 10, preferably an integer of 0 to 5, and f is an integer of 1 to 7, preferably an integer of 1 to 3.

[0066] In formula (AL-2a) or (AL-2b), L A is a (f+1)-valent aliphatic saturated hydrocarbon group having 1 to 50 carbon atoms, a (f+1)-valent alicyclic saturated hydrocarbon group having 3 to 50 carbon atoms, a (f+1)-valent aromatic hydrocarbon group having 6 to 50 carbon atoms, or a (f+1)-valent heterocyclic group having 3 to 50 carbon atoms. In addition, some of the carbon atoms of these groups may be substituted with a heteroatom-containing group, and some of the hydrogen atoms bonded to the carbon atoms of these groups may be substituted with a hydroxy group, a carboxy group, an acyl group, or a fluorine atom. A L is preferably a saturated hydrocarbon group having 1 to 20 carbon atoms, such as a saturated hydrocarbylene group, a trivalent saturated hydrocarbon group, or a tetravalent saturated hydrocarbon group, or an arylene group having 6 to 30 carbon atoms. The saturated hydrocarbon group may be linear, branched, or cyclic.B is -C(=O)-O-, -NH-C(=O)-O- or -NH-C(=O)-NH-.

[0067] Examples of the crosslinked acetal group represented by formula (AL-2a) or (AL-2b) include groups represented by the following formulae (AL-2)-70 to (AL-2)-77. [ka] (In the formula, the dashed lines represent bonds.)

[0068] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cyclic unsaturated aliphatic hydrocarbyl group having 3 to 20 carbon atoms, and an aryl group having 6 to 10 carbon atoms. In addition, R L5 and R L6 And, R L5 and R L7 and, or R L6 and R L7 may be bonded to each other to form an alicyclic ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.

[0069] Examples of the group represented by formula (AL-3) include a tert-butyl group, a 1,1-diethylpropyl group, a 1-ethylnorbornyl group, a 1-methylcyclopentyl group, a 1-ethylcyclopentyl group, a 1-isopropylcyclopentyl group, a 1-methylcyclohexyl group, a 2-(2-methyl)adamantyl group, a 2-(2-ethyl)adamantyl group, and a tert-pentyl group.

[0070] Further, examples of the group represented by formula (AL-3) include groups represented by the following formulae (AL-3)-1 to (AL-3)-19. [ka] (In the formula, the dashed lines represent bonds.)

[0071] In formulas (AL-3)-1 to (AL-3)-19, R L14 R are each independently a saturated hydrocarbyl group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms. L15 and R L17 R are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms. L16 R is an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. The aryl group is preferably a phenyl group. F is a fluorine atom or a trifluoromethyl group, and g is an integer of 1 to 5.

[0072] Further examples of the acid labile group include groups represented by the following formula (AL-3)-20 or (AL-3)-21: The acid labile group may cause intramolecular or intermolecular crosslinking of the polymer. [ka] (In the formula, the dashed lines represent bonds.)

[0073] In formulas (AL-3)-20 and (AL-3)-21, R L14 is the same as above. R L18 is a (h+1)-valent saturated hydrocarbylene group having 1 to 20 carbon atoms or a (h+1)-valent arylene group having 6 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. The saturated hydrocarbylene group may be linear, branched, or cyclic. h is an integer of 1 to 3.

[0074] Examples of monomers that provide a repeating unit containing an acid labile group represented by formula (AL-3) include (meth)acrylic acid esters containing an exo structure represented by formula (AL-3)-22 below. [ka]

[0075] In formula (AL-3)-22, R A is the same as above. R Lc1 R is a saturated hydrocarbyl group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms which may be substituted. The saturated hydrocarbyl group may be linear, branched or cyclic. Lc2 ~R Lc11 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 15 carbon atoms which may contain a heteroatom. Examples of the heteroatom include an oxygen atom. Examples of the hydrocarbyl group include an alkyl group having 1 to 15 carbon atoms and an aryl group having 6 to 15 carbon atoms. R Lc2 and R Lc3 And, R Lc4 and R Lc6 And, R Lc4 and R Lc7 And, R Lc5 and R Lc7 And, R Lc5 and R Lc11 And, R Lc6 and R Lc10 And, R Lc8 and R Lc9 and, or R Lc9 and R Lc10 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, and in this case, the group participating in the bond is a hydrocarbylene group having 1 to 15 carbon atoms which may contain a heteroatom. Lc2 and R Lc11 And, R Lc8 and R Lc11 and, or R Lc4 and R Lc6 The carbon atoms bonded to adjacent carbons may bond directly to each other to form a double bond. This formula also represents an enantiomer.

[0076] Here, examples of monomers that provide the repeating unit represented by formula (AL-3)-22 include those described in JP-A-2000-327633. Specific examples include, but are not limited to, those shown below. In the following formula, RA is the same as above. [ka]

[0077] Examples of monomers that provide a repeating unit containing an acid labile group represented by formula (AL-3) include (meth)acrylic acid esters containing a furandiyl group, a tetrahydrofurandiyl group, or an oxanorbornanediyl group represented by the following formula (AL-3)-23. [ka]

[0078] In formula (AL-3)-23, R A is the same as above. R Lc12 and R Lc13 R is each independently a hydrocarbyl group having 1 to 10 carbon atoms. Lc12 and R Lc13 may be bonded to each other to form an alicyclic ring together with the carbon atom to which they are attached. Lc14 R is a furandiyl group, a tetrahydrofurandiyl group, or an oxanorbornanediyl group. Lc15 is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be linear, branched, or cyclic. Specific examples thereof include saturated hydrocarbyl groups having 1 to 10 carbon atoms.

[0079] Examples of monomers that provide the repeating unit represented by formula (AL-3)-23 include, but are not limited to, those shown below. A is the same as above, Ac is an acetyl group, and Me is a methyl group. [ka]

[0080] [ka]

[0081] The base polymer may further include a repeating unit c containing an adhesive group selected from a hydroxy group, a carboxy group, a lactone ring, a carbonate bond, a thiocarbonate bond, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonate ester bond, a cyano group, an amide bond, -OC(=O)-S-, and -OC(=O)-NH-.

[0082] Examples of monomers that provide the repeating unit c include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] [ka]

[0087] [ka]

[0088] [ka]

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] The base polymer may further contain at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (d1) (hereinafter also referred to as repeating unit d1), a repeating unit represented by the following formula (d2) (hereinafter also referred to as repeating unit d2), and a repeating unit represented by the following formula (d3) (hereinafter also referred to as repeating unit d3). [ka]

[0093] In formulas (d1) to (d3), R A are each independently a hydrogen atom or a methyl group. 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. 11 Z is 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 groups, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 2 is a single bond or an ester bond. 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)-. Z 31Z is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group obtained by combining these and having 7 to 18 carbon atoms, and may contain a carbonyl group, an ester bond, an ether bond, a bromine atom, or an iodine atom. 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. 5 is a single bond, a methylene group, an ethylene group, a phenylene 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. 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene 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, or a hydroxy group.

[0094] In formulas (d1) to (d3), R 21 ~R 28 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be linear, branched, or cyclic. Specific examples thereof include R 101 ~R 105 Examples of the hydrocarbyl group represented by the formula (I) include the same as those mentioned above.

[0095] Also, R 23 and R 24 or R 26 and R 27 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 may be any of the groups represented by R 101 and R 102 and the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0096] In formula (d1), M -is a non-nucleophilic counter ion. 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.

[0097] Further examples of the non-nucleophilic counter ion include a sulfonate ion represented by the following formula (d1-1) in which the α-position is substituted with a fluorine atom, and a sulfonate ion represented by the following formula (d1-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group. [ka]

[0098] In formula (d1-1), 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. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0099] In formula (d1-2), 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 the hydrocarbylcarbonyl group may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl group and the hydrocarbylcarbonyl group may have a hydrocarbyl moiety that is saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0100] Examples of the cation of the monomer that gives the repeating unit d1 include, but are not limited to, those shown below. A is the same as above. [ka]

[0101] Examples of the cation of the monomer that gives the repeating unit d2 or d3 include the same as those exemplified as the cation of the sulfonium salt represented by formula (1-1) described later.

[0102] Examples of the anion of the monomer that gives the repeating unit d2 include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0103] [ka]

[0104] [ka]

[0105] [ka]

[0106] [ka]

[0107] [ka]

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] [ka]

[0113] [ka]

[0114] Examples of the anion of the monomer that gives the repeating unit d3 include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0115] The repeating units d1 to d3 function as an acid generator. By binding the acid generator to the polymer main chain, acid diffusion is reduced, and a decrease in resolution due to blurring of the acid diffusion can be prevented. Furthermore, the LER, LWR, and CDU are improved by uniformly dispersing the acid generator. When a base polymer containing the repeating units d1 to d3 (i.e., a polymer-bound acid generator) is used, the blending of an additive-type acid generator, which will be described later, can be omitted.

[0116] The base polymer may further include a repeating unit e that does not include an amino group and includes an iodine atom. Examples of monomers that provide the repeating unit e include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0117] [ka]

[0118] [ka]

[0119] The base polymer may contain a repeating unit f other than the repeating units described above. Examples of the repeating unit f include those derived from styrene, vinylnaphthalene, indene, acenaphthylene, coumarin, and coumarone.

[0120] In the base polymer, the content ratios of the repeating units a, b1, b2, c, d1, d2, d3, e, and f are preferably 0 < a < 1.0, 0 ≤ b1 ≤ 0.9, 0 ≤ b2 ≤ 0.9, 0 < b1 + b2 ≤ 0.9, 0 ≤ c ≤ 0.9, 0 ≤ d1 ≤ 0.5, 0 ≤ d2 ≤ 0.5, 0 ≤ d3 ≤ 0.5, 0 ≤ d1 + d2 + d3 ≤ 0.5, 0 ≤ e ≤ 0.5, and 0 ≤ f ≤ 0.5; more preferably 0.001 ≤ a ≤ 0.8, 0 ≤ b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 < b1 + b2 ≤ 0.8, 0 ≤ c ≤ 0.8, 0 ≤ d1 ≤ 0.4, 0 ≤ d2 ≤ 0.4, 0 ≤ d3 ≤ 0.4, 0 ≤ d1 + d2 + d3 ≤ 0.4, 0 ≤ e ≤ 0.4, and 0 ≤ f ≤ 0.4; and even more preferably 0.01 ≤ a ≤ 0.7, 0 ≤ b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 < b1 + b2 ≤ 0.7, 0 ≤ c ≤ 0.7, 0 ≤ d1 ≤ 0.3, 0 ≤ d2 ≤ 0.3, 0 ≤ d3 ≤ 0.3, 0 ≤ d1 + d2 + d3 ≤ 0.3, 0 ≤ e ≤ 0.3, and 0 ≤ f ≤ 0.3. However, a + b1 + b2 + c + d1 + d2 + d3 + e + f = 1.0.

[0121] To synthesize the base polymer, for example, monomers that provide the aforementioned repeating units may be heated in an organic solvent with the addition of a radical polymerization initiator to carry out polymerization.

[0122] Examples of the organic solvent used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, etc. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, etc. The temperature during polymerization is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0123] When copolymerizing a monomer containing a hydroxy group, during polymerization, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid such as an ethoxyethoxy group, and then deprotected with a weak acid and water after polymerization, or it may be substituted with an acetyl group, formyl group, pivaloyl group, etc., and then subjected to alkaline hydrolysis after polymerization.

[0124] When hydroxystyrene or hydroxyvinylnaphthalene is copolymerized, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group may be deprotected by the above-mentioned alkaline hydrolysis to give hydroxystyrene or hydroxyvinylnaphthalene.

[0125] As the base for the alkaline hydrolysis, ammonia water, triethylamine, etc. can be used. The reaction temperature is preferably −20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0126] The base polymer has a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) using THF as a solvent of preferably 1,000 to 500,000, more preferably 2,000 to 30,000. If the Mw is too small, the resist material will have poor heat resistance, whereas if the Mw is too large, the alkali solubility will decrease, making the base material more susceptible to footing after pattern formation.

[0127] In addition, when the base polymer has a wide molecular weight distribution (Mw / Mn), the presence of low-molecular weight and high-molecular weight polymers may cause foreign matter to be found on the pattern after exposure, or the shape of the pattern may be deteriorated. As the pattern rule becomes finer, the effects of Mw and Mw / Mn tend to become greater, so in order to obtain a resist material that is suitable for fine pattern dimensions, it is preferable that the Mw / Mn of the base polymer has a narrow distribution of 1.0 to 2.0, particularly 1.0 to 1.5.

[0128] The base polymer may include two or more polymers having different composition ratios, Mw, or Mw / Mn, or may be a blend of a polymer containing the repeating unit a and a polymer not containing the repeating unit a.

[0129] [Acid generator] The positive resist material of the present invention may contain an acid generator (hereinafter, also referred to as an additive acid generator) that generates a strong acid. The strong acid here means a compound having sufficient acidity to cause a deprotection reaction of an acid labile group of a base polymer. The acid generator may be, for example, a compound (photoacid generator) that generates an acid in response to actinic rays or radiation. The photoacid generator may be any compound that generates an acid upon irradiation with high energy rays, but is preferably one that generates a sulfonic acid, an imide acid, or a methide acid. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate type acid generators. Specific examples of photoacid generators include those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A.

[0130] In addition, as the photoacid generator, a sulfonium salt represented by the following formula (1-1) or an iodonium salt represented by the following formula (1-2) can also be suitably used. [ka]

[0131] In formulas (1-1) and (1-2), R 101 ~R 105 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0132] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0133] R 101 ~R 105The hydrocarbyl group having 1 to 20 carbon atoms represented by the following formula may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, or an icosyl group; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, or an adamantyl group; alkenyl groups, such as a vinyl group, a propenyl group, a butenyl group, or a hexenyl group; ethynyl group, propenyl group, alkynyl groups having 2 to 20 carbon atoms, such as a norbornenyl group, butynyl group, etc.; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexenyl group, norbornenyl group, etc.; aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, a n-propylphenyl group, an isopropylphenyl group, a n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, a n-propylnaphthyl group, an isopropylnaphthyl group, a n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, a tert-butylnaphthyl group, etc.; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group, a phenethyl group, etc.; and groups obtained by combining these.

[0134] In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., so that these groups may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc.

[0135] Also, R 101 and R 102 However, they may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is preferably one having the structure shown below. [ka] (In the formula, the dashed line represents R 103 It is a bond with .)

[0136] Examples of the cation of the sulfonium salt represented by formula (1-1) include, but are not limited to, those shown below. [ka]

[0137] [ka]

[0138] [ka]

[0139] [ka]

[0140] [ka]

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] [ka]

[0149] [ka]

[0150] Examples of the cation of the iodonium salt represented by formula (1-2) include, but are not limited to, those shown below. [ka]

[0151] [ka]

[0152] In formulas (1-1) and (1-2), Xa - is an anion selected from the following formulas (1A) to (1D). [ka]

[0153] In formula (1A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0154] The anion represented by formula (1A) is preferably one represented by the following formula (1A'). [ka]

[0155] In formula (1A'), R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 111 is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and more preferably an oxygen atom. In order to obtain high resolution in the formation of a fine pattern, the hydrocarbyl group is preferably one having 6 to 30 carbon atoms.

[0156] R 111The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group, a nonyl group, an undecyl group, a tridecyl group, a pentadecyl group, a heptadecyl group, and an icosanyl group; a cyclopentyl group, a cyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, a 1-adamantylmethyl group, a norbornyl group, Examples of the alkyl group include cyclic saturated hydrocarbyl groups having 3 to 38 carbon atoms, such as a norbornylmethyl group, a tricyclodecanyl group, a tetracyclododecanyl group, a tetracyclododecanylmethyl group, and a dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 38 carbon atoms, such as an allyl group and a 3-cyclohexenyl group; aryl groups having 6 to 38 carbon atoms, such as a phenyl group, a 1-naphthyl group, and a 2-naphthyl group; aralkyl groups having 7 to 38 carbon atoms, such as a benzyl group and a diphenylmethyl group; and groups obtained by combining these groups.

[0157] In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the group containing a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. Examples of hydrocarbyl groups containing heteroatoms include a tetrahydrofuryl group, a methoxymethyl group, an ethoxymethyl group, a methylthiomethyl group, an acetamidomethyl group, a trifluoroethyl group, a (2-methoxyethoxy)methyl group, an acetoxymethyl group, a 2-carboxy-1-cyclohexyl group, a 2-oxopropyl group, a 4-oxo-1-adamantyl group, and a 3-oxocyclohexyl group.

[0158] Synthesis of sulfonium salts containing an anion represented by formula (1A') is described in detail in JP-A-2007-145797, JP-A-2008-106045, JP-A-2009-7327, JP-A-2009-258695, etc. In addition, sulfonium salts described in JP-A-2010-215608, JP-A-2012-41320, JP-A-2012-106986, JP-A-2012-153644, etc. are also preferably used.

[0159] Examples of the anion represented by formula (1A) include the same anions as those exemplified as the anion represented by formula (1A) in JP 2018-197853 A.

[0160] In formula (1B), R fb1 and R fb2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula R include the same as those exemplified above. fb1 and R fb2 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 means that the groups (-CF2-SO2-N - -SO2-CF2-) may form a ring, in which case, R fb1 and R fb2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0161] In formula (1C), R fc1 , R fc2 and R fc3 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R111 Examples of the hydrocarbyl group represented by the formula R include the same as those exemplified above. fc1 , R fc2 and R fc3 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 means that the groups (-CF2-SO2-C - -SO2-CF2-) may form a ring, in which case, R fc1 and R fc2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0162] In formula (1D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0163] The synthesis of a sulfonium salt containing an anion represented by formula (1D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

[0164] Examples of the anion represented by formula (1D) include the same anions as those exemplified as the anion represented by formula (1D) in JP 2018-197853 A.

[0165] Although the photoacid generator containing the anion represented by formula (1D) does not have a fluorine atom at the α-position of the sulfo group, it has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave the acid labile group in the base polymer, and can therefore be used as a photoacid generator.

[0166] As the photoacid generator, a compound represented by the following formula (2) can also be suitably used. [ka]

[0167] In formula (2), R 201 and R 202 R are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 201 , R 202 and R 203 Any two of 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 is as defined in the description of formula (1-1) as R 101 and R 102 and , when bonded to each other, can form a ring together with the sulfur atom to which they are bonded, similar to those exemplified above.

[0168] R 201 and R 202 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl and n-decyl groups; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl and tricyclo[5.2.1.0]. 2,6cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as a decanyl group, and an adamantyl group; aryl groups having 6 to 30 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, a tert-butylnaphthyl group, and an anthracenyl group; and groups obtained by combining these groups. In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., so that these groups may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc.

[0169] R 203The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include alkanediyl groups having 1 to 30 carbon atoms, such as a methanediyl group, an ethane-1,1-diyl group, an ethane-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-1,12-diyl group, a tridecane-1,13-diyl group, a tetradecane-1,14-diyl group, a pentadecane-1,15-diyl group, a hexadecane-1,16-diyl group, and a heptadecane-1,17-diyl group; a cyclopentanediyl group, a cyclohexanediyl group, and the like. Examples of the alkylene groups include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as axanediyl group, norbornanediyl group, and adamantanediyl group; arylene groups having 6 to 30 carbon atoms, such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group, an isobutylphenylene group, a sec-butylphenylene group, a tert-butylphenylene group, a naphthylene group, a methylnaphthylene group, an ethylnaphthylene group, an n-propylnaphthylene group, an isopropylnaphthylene group, an n-butylnaphthylene group, an isobutylnaphthylene group, a sec-butylnaphthylene group, and a tert-butylnaphthylene group; and groups obtained by combining these groups. In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., or some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., so that the groups may contain hydroxy groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydrides, haloalkyl groups, etc. As the heteroatom, oxygen atoms are preferred.

[0170] In formula (2), L Cis a hydrocarbylene group having 1 to 20 carbon atoms which may contain a single bond, an ether bond, or a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 203 Examples of the hydrocarbylene group represented by the following formula include the same as those exemplified above.

[0171] In formula (2), X A , X B , X C and X D are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. A , X B , X C and X D At least one of the groups is a fluorine atom or a trifluoromethyl group.

[0172] In formula (2), k is an integer of 0 to 3.

[0173] The photoacid generator represented by formula (2) is preferably one represented by the following formula (2'). [ka]

[0174] In formula (2'), L C is the same as above. R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula: x and y each independently represent an integer of 0 to 5, and z represents an integer of 0 to 4.

[0175] Examples of the photoacid generator represented by formula (2) include the same as those exemplified as the photoacid generator represented by formula (2) in JP2017-026980A.

[0176] Among the photoacid generators, those containing an anion represented by formula (1A') or (1D) are particularly preferred because of their small acid diffusion and excellent solubility in solvents, while those represented by formula (2') are particularly preferred because of their extremely small acid diffusion.

[0177] The photoacid generator may be a sulfonium salt or an iodonium salt having an anion containing an aromatic ring substituted with an iodine atom or a bromine atom. Examples of such salts include those represented by the following formula (3-1) or (3-2). [ka]

[0178] In formulas (3-1) and (3-2), r is an integer satisfying 1≦r≦3. s and t are integers satisfying 1≦s≦5, 0≦t≦3, and 1≦s+t≦5. s is preferably an integer satisfying 1≦s≦3, more preferably 2 or 3. t is preferably an integer satisfying 0≦t≦2.

[0179] In formulas (3-1) and (3-2), X BI is an iodine atom or a bromine atom, and when r and / or s is 2 or more, they may be the same or different.

[0180] In formulas (3-1) and (3-2), L 11 is a single bond, an ether bond or 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.

[0181] In formulas (3-1) and (3-2), L 12represents a single bond or a divalent linking group having 1 to 20 carbon atoms when r is 1, and represents a (r+1)-valent linking group having 1 to 20 carbon atoms when r is 2 or 3, which linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0182] In formulas (3-1) and (3-2), R 401 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms or a saturated hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond, or 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D Or -N(R 401C )-C(=O)-OR 401D R 401A and R 401B R are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 401C R 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. 401Dis 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 saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbyloxycarbonyl group, saturated hydrocarbylcarbonyl group, and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When r and / or t is 2 or more, each R 401 may be the same or different from each other.

[0183] Of these, R 401 Examples of the hydroxyl group include -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-OR 401D , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group, and the like are preferred.

[0184] In formulas (3-1) and (3-2), Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, at least one of which is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine to form a carbonyl group. 3 and Rf 4 are preferably both fluorine atoms.

[0185] In formulas (3-1) and (3-2), R 402 ~R 406are 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 101 ~R 105 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. In addition, some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the carbon atoms of these groups may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate ester bond. 402 and R 403 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is as defined in the description of formula (1-1) as R 101 and R 102 and , when bonded to each other, can form a ring together with the sulfur atom to which they are bonded, similar to those exemplified above.

[0186] Examples of the cation of the sulfonium salt represented by formula (3-1) include the same as those exemplified as the cation of the sulfonium salt represented by formula (1-1). Examples of the cation of the iodonium salt represented by formula (3-2) include the same as those exemplified as the cation of the iodonium salt represented by formula (1-2).

[0187] Examples of the anion of the onium salt represented by formula (3-1) or (3-2) include, but are not limited to, those shown below. In the following formula, X BI is the same as above. [ka]

[0188] [ka]

[0189]

change

[0190]

change

[0191]

change

[0192]

change

[0193]

change

[0194]

change

[0195]

change

[0196]

change

[0197]

change

[0198]

change

[0199]

change

[0200]

change

[0201]

change

[0202]

change

[0203]

change

[0204]

change

[0205]

change

[0206]

change

[0207]

change

[0208]

change

[0209]

change

[0210] In the positive resist material of the present invention, the content of the additive acid generator is preferably 0.1 to 50 parts by mass, and more preferably 1 to 40 parts by mass, relative to 100 parts by mass of the base polymer. When the base polymer contains repeating units d1 to d3 and / or contains an additive acid generator, the positive resist material of the present invention can function as a chemically amplified positive resist material.

[0211] [Organic solvents] The positive resist material of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the above-mentioned components and the components described below. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] to

[0145] of JP-A-2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol Examples of the monoethyl ether include ethers such as propylene glycol monoethyl ether, 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; and lactones such as γ-butyrolactone.

[0212] In the positive resist composition of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, and more preferably 200 to 8,000 parts by mass, relative to 100 parts by mass of the base polymer. The organic solvent may be used alone or in combination of two or more kinds.

[0213] [Other ingredients] In addition to the above-mentioned components, a quencher, a surfactant, a dissolution inhibitor, a water repellency improver, etc. can be appropriately combined and blended according to the purpose to form a positive resist material, and the base polymer in the exposed area is accelerated in dissolution rate in a developer by a catalytic reaction, so that a positive resist material with extremely high sensitivity can be obtained. In this case, the resist film has high dissolution contrast and resolution, has a large exposure margin, is excellent in process adaptability, and has a good pattern shape after exposure, while the dimensional difference between coarse and dense regions is small, especially because acid diffusion can be suppressed, and therefore it is highly practical and can be very effective as a resist material for VLSI.

[0214] The quencher may be a conventional basic compound. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonic acid ester bond, or compounds having a carbamate group described in JP-A-3790649 are preferred. By adding such a basic compound, for example, the diffusion rate of the acid in the resist film can be further suppressed or the shape can be corrected.

[0215] Further, the quencher may be an onium salt such as a sulfonium salt, an iodonium salt, or an ammonium salt of a sulfonic acid or a carboxylic acid not fluorinated at the α-position, as described in JP-A-2008-158339. A sulfonic acid, an imide acid, or a methide acid having a fluorinated α-position is necessary for deprotecting an acid labile group of a carboxylic acid ester, but a sulfonic acid or a carboxylic acid not fluorinated at the α-position is released by salt exchange with an onium salt having a non-fluorinated α-position. A sulfonic acid or a carboxylic acid not fluorinated at the α-position does not cause a deprotection reaction, and therefore functions as a quencher.

[0216] Examples of such quenchers include a compound represented by the following formula (4) (an onium salt of a sulfonic acid not fluorinated at the α-position) and a compound represented by the following formula (5) (an onium salt of a carboxylic acid). [ka]

[0217] In formula (4), R 501 represents a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group.

[0218] The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-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 such as ]decanyl group, adamantyl group, and adamantylmethyl group; alkenyl groups such as vinyl group, allyl group, propenyl group, butenyl group, and hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups such as cyclohexenyl group; aryl groups such as phenyl group, naphthyl group, alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-n-butylphenyl group, etc.), dialkylphenyl group (2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group, etc.), alkylnaphthyl group (methylnaphthyl group, ethylnaphthyl group, etc.), dialkylnaphthyl group (dimethylnaphthyl group, diethylnaphthyl group, etc.); heteroaryl groups such as thienyl group; and aralkyl groups such as benzyl group, 1-phenylethyl group, and 2-phenylethyl group.

[0219] In addition, a portion of the hydrogen atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and a portion of the carbon atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, these groups may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like. Examples of hydrocarbyl groups containing heteroatoms include alkoxyphenyl groups such as 4-hydroxyphenyl group, 4-methoxyphenyl group, 3-methoxyphenyl group, 2-methoxyphenyl group, 4-ethoxyphenyl group, 4-tert-butoxyphenyl group, and 3-tert-butoxyphenyl group; alkoxynaphthyl groups such as methoxynaphthyl group, ethoxynaphthyl group, n-propoxynaphthyl group, and n-butoxynaphthyl group; dialkoxynaphthyl groups such as dimethoxynaphthyl group and diethoxynaphthyl group; and aryloxoalkyl groups such as 2-aryl-2-oxoethyl group, 2-(1-naphthyl)-2-oxoethyl group, and 2-(2-naphthyl)-2-oxoethyl group.

[0220] In formula (5), R 502R is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. 502 The hydrocarbyl group represented by R 501 Examples of the hydrocarbyl group include the same as those exemplified above. Other specific examples include fluorine-containing alkyl groups such as a trifluoromethyl group, a trifluoroethyl group, a 2,2,2-trifluoro-1-methyl-1-hydroxyethyl group, and a 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl group; and fluorine-containing aryl groups such as a pentafluorophenyl group and a 4-trifluoromethylphenyl group.

[0221] In formulas (4) and (5), Mq + is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation, or an ammonium cation, and more preferably a sulfonium cation or an iodonium cation. The sulfonium cation may be the same as the cation exemplified in the sulfonium salt represented by formula (1-1). The iodonium cation may be the same as the cation exemplified in the iodonium salt represented by formula (1-2).

[0222] As the quencher, a sulfonium salt of an iodized benzene ring-containing carboxylic acid represented by the following formula (6) can also be suitably used. [ka]

[0223] In formula (6), R 601 represents a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which some or all of the hydrogen atoms may be substituted with halogen atoms, or -N(R 601A )-C(=O)-R 601BOr -N(R 601A )-C(=O)-OR 601B R 601A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 601B is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms.

[0224] In formula (6), x' is an integer of 1 to 5. y' is an integer of 0 to 3. z' is an integer of 1 to 3. L 21 is a single bond or a (z'+1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxyl group, and a carboxyl group. The saturated hydrocarbyl group, the saturated hydrocarbyloxy group, the saturated hydrocarbylcarbonyloxy group, and the saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When y' and / or z' is 2 or more, each R 601 may be the same or different from each other.

[0225] In formula (6), R 602 , R 603 and R 604 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. In addition, some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, an oxo group, a cyano group, a nitro group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the carbon atoms of these groups may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate ester bond. In addition, R 602 and R 603may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0226] Specific examples of the compound represented by formula (6) include those described in JP 2017-219836 A. This also has high absorption, a high sensitizing effect, and a high acid diffusion control effect.

[0227] Further examples of the quencher include the polymer-type quencher described in JP 2008-239918 A. This enhances the rectangularity of the resist pattern by being oriented on the surface of the resist film. The polymer-type quencher also has the effect of preventing film loss of the pattern and rounding of the pattern top when a protective film for immersion exposure is applied.

[0228] In the positive resist composition of the present invention, the content of the quencher is preferably from 0 to 5 parts by mass, and more preferably from 0 to 4 parts by mass, relative to 100 parts by mass of the base polymer. The quenchers may be used alone or in combination of two or more.

[0229] Examples of the surfactant include those described in paragraphs

[0165] to

[0166] of JP 2008-111103 A. The addition of a surfactant can further improve or control the coatability of the resist material. When the positive resist material of the present invention contains the surfactant, the content is preferably 0.0001 to 10 parts by mass per 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more types.

[0230] By adding a dissolution inhibitor, the difference in dissolution rate between exposed and unexposed areas can be further increased, and the resolution can be further improved. The dissolution inhibitor includes a compound having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule, in which the hydrogen atoms of the phenolic hydroxyl groups are substituted with acid labile groups at a ratio of 0 to 100 mol % as a whole, or a compound having a carboxyl group in the molecule, in which the hydrogen atoms of the carboxyl groups are substituted with acid labile groups at an average ratio of 50 to 100 mol % as a whole. Specific examples include bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalene carboxylic acid, adamantane carboxylic acid, and hydroxyl groups of cholic acid, and compounds in which hydrogen atoms of carboxyl groups are substituted with acid labile groups, and the like, which are described in, for example, paragraphs

[0155] to

[0178] of JP2008-122932A.

[0231] In the positive resist composition of the present invention, the content of the dissolution inhibitor is preferably 0 to 50 parts by mass, and more preferably 5 to 40 parts by mass, relative to 100 parts by mass of the base polymer. The dissolution inhibitor may be used alone or in combination of two or more kinds.

[0232] The positive resist material of the present invention may contain a water repellency improver to improve the water repellency of the resist film surface. The water repellency improver can be used in immersion lithography without using a topcoat. As the water repellency improver, a polymer containing a fluorinated alkyl group, a polymer containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue of a specific structure, and the like are preferred, and those exemplified in JP-A-2007-297590 and JP-A-2008-111103 are more preferred. The water repellency improver needs to be dissolved in an alkaline developer or an organic solvent developer. The water repellency improver having the specific 1,1,1,3,3,3-hexafluoro-2-propanol residue described above has good solubility in the developer. As a water repellency improver, a polymer containing a repeating unit containing an amino group or an amine salt is highly effective in preventing the evaporation of acid during post-exposure baking (PEB) and preventing poor opening of a hole pattern after development. In the positive resist composition of the present invention, the content of the water repellency improver is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the base polymer. The water repellency improver may be used alone or in combination of two or more kinds.

[0233] The positive resist material of the present invention may also contain acetylene alcohols. Examples of the acetylene alcohols include those described in paragraphs

[0179] to

[0182] of JP 2008-122932 A. The content of the acetylene alcohols in the positive resist material of the present invention is preferably 0 to 5 parts by mass per 100 parts by mass of the base polymer. The acetylene alcohols may be used alone or in combination of two or more.

[0234] [Pattern formation method] When the positive resist material of the present invention is used in various integrated circuit manufacturing, known lithography techniques can be applied.For example, the pattern forming method includes the steps of forming a resist film on a substrate using the above-mentioned resist material, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0235] First, the positive resist material of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., so that the coating film thickness is 0.01 to 2 μm. This is pre-baked on a hot plate, preferably at 60 to 150 ° C., for 10 seconds to 30 minutes, more preferably at 80 to 120 ° C., for 30 seconds to 20 minutes, to form a resist film.

[0236] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, EB, EUV radiation with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. When ultraviolet radiation, far ultraviolet radiation, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. are used as the high-energy radiation, the exposure dose is preferably 1 to 200 mJ / cm2, either directly or using a mask for forming a desired pattern. 2 Approximately, more preferably 10 to 100 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 100 μC / cm 2 Approximately, more preferably 0.5 to 50 μC / cm 2The positive resist material of the present invention is suitable for fine patterning using high energy rays such as KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, γ-rays, and synchrotron radiation, and is particularly suitable for fine patterning using EB or EUV.

[0237] After the exposure, PEB may be performed on a hot plate or in an oven, preferably at 50 to 150° C. for 10 seconds to 30 minutes, more preferably at 60 to 120° C. for 30 seconds to 20 minutes.

[0238] After exposure or PEB, development is carried out using a developer of an alkaline aqueous solution such as 0.1 to 10 mass %, preferably 2 to 5 mass %, of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), or the like for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by a conventional method such as a dip method, a puddle method, a spray method, or the like. The irradiated areas are dissolved in the developer, while the unexposed areas are not dissolved, and the desired positive pattern is formed on the substrate.

[0239] A positive resist material containing a base polymer containing an acid labile group can be used to perform negative development to obtain a negative pattern by organic solvent development. The developer used in this case can be 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, Examples of the organic solvent include methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents can be used alone or in combination of two or more.

[0240] At the end of the development, rinsing is performed. As the rinsing liquid, a solvent that is miscible with the developer and does not dissolve the resist film is preferable. As such a solvent, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms are preferably used.

[0241] Specific examples of alcohols having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, and 3-hexanol. , 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol.

[0242] Examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, and di-n-hexyl ether.

[0243] Examples of alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Examples of alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Examples of alkynes having 6 to 12 carbon atoms include hexine, heptine, octyne, etc.

[0244] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0245] 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.

[0246] The developed hole pattern or trench pattern can also be shrunk by thermal flow, RELACS technology, or DSA technology. A shrink agent is applied onto the hole pattern, and the shrink agent crosslinks on the surface of the resist film due to the diffusion of an acid catalyst from the resist film during baking, and the shrink agent adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, and excess shrink agent is removed to reduce the hole pattern. EXAMPLES

[0247] The present invention will be specifically described below with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples.

[0248] [1] Synthesis of monomer [Synthesis Examples 1-1 to 1-12] Synthesis of Monomers M-1 to M-12 A monomer having a nitrogen atom and a sulfonamide having an aromatic ring substituted with an iodine atom were mixed to obtain the following monomers M-1 to M-12. [ka]

[0249] [ka]

[0250] [ka]

[0251] [2] Polymer synthesis The PAG monomers PM-1 to PM-3 used in the synthesis of the polymers are as follows: The Mw of the polymers is a polystyrene-equivalent measured value by GPC using THF as a solvent. [ka]

[0252] [Synthesis Example 2-1] Synthesis of Polymer P-1 In a 2L flask, 4.2g of M-1, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 5.4g of 4-hydroxystyrene, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-1. The composition of P-1 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0253] [Synthesis Example 2-2] Synthesis of Polymer P-2 In a 2L flask, 2.7g of M-2, 7.3g of 1-methyl-1-cyclohexyl methacrylate, 5.0g of 4-hydroxystyrene, 11.0g of PM-2, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-2. The composition of P-2 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0254] [Synthesis Example 2-3] Synthesis of Polymer P-3 In a 2L flask, 3.8g of M-3, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.6g of 3-hydroxystyrene, 11.9g of PM-1, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-3. The composition of P-3 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0255] [Synthesis Example 2-4] Synthesis of polymer P-4 In a 2L flask, 4.0g of M-4, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.6g of 3-hydroxystyrene, 12.1g of PM-3, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-4. The composition of P-4 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0256] [Synthesis Example 2-5] Synthesis of Polymer P-5 In a 2L flask, 4.0g of M-5, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.6g of 3-hydroxystyrene, 11.0g of PM-2, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-5. The composition of P-5 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0257] [Synthesis Example 2-6] Synthesis of Polymer P-6 In a 2L flask, 6.2g of M-6, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.4g of 3-hydroxystyrene, 11.0g of PM-2, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-6. The composition of P-6 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0258] [Synthesis Example 2-7] Synthesis of polymer P-7 In a 2L flask, 6.0g of M-7, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.4g of 3-hydroxystyrene, 11.0g of PM-2, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-7. The composition of P-7 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0259] [Synthesis Example 2-8] Synthesis of Polymer P-8 In a 2L flask, 5.4g of M-8, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.4g of 3-hydroxystyrene, 11.0g of PM-2, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-8. The composition of P-8 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0260] [Synthesis Example 2-9] Synthesis of Polymer P-9 In a 2L flask, 5.7g of M-9, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.8g of 3-hydroxystyrene, 11.0g of PM-2, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-9. The composition of P-9 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0261] [Synthesis Example 2-10] Synthesis of Polymer P-10 In a 2L flask, 4.5g of M-10, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.8g of 3-hydroxystyrene, 11.0g of PM-2, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-10. The composition of P-10 was 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0262] [Synthesis Example 2-11] Synthesis of Polymer P-11 In a 2L flask, 4.4g of M-11, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.8g of 3-hydroxystyrene, 11.0g of PM-2, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-11. The composition of P-11 was 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0263] [Synthesis Example 2-12] Synthesis of Polymer P-12 In a 2L flask, 3.2g of M-12, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.8g of 3-hydroxystyrene, 11.0g of PM-2, and 40g of THF as a solvent were added. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60°C to obtain polymer P-12. The composition of P-12 was 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0264] [Comparative Synthesis Example 1] Synthesis of Comparative Polymer cP-1 Comparative polymer cP-1 was obtained in the same manner as in Synthesis Example 2-1, except that M-1 was not used. The composition of cP-1 was 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0265] [Comparative Synthesis Example 2] Synthesis of Comparative Polymer cP-2 Comparative polymer cP-2 was obtained in the same manner as in Synthesis Example 2-1, except that 2-(dimethylamino)ethyl methacrylate was used instead of M-1. The composition of cP-2 was 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0266] [Comparative Synthesis Example 3] Synthesis of Comparative Polymer cP-3 Comparative polymer cP-3 was obtained in the same manner as in Synthesis Example 2-2, except that M-2 was not used and 1-methyl-1-cyclopentyl methacrylate was used instead of 1-methyl-1-cyclohexyl methacrylate. The composition of cP-3 was: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0267] [3] Preparation and evaluation of resist materials [Examples 1 to 12, Comparative Examples 1 to 3] (1) Preparation of resist material A solution of each component in the composition shown in Table 1 in a solvent containing 100 ppm of surfactant FC-4430 (manufactured by 3M) was filtered through a 0.2 μm filter to prepare a positive resist material.

[0268] In Table 1, the components are as follows: Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (Diacetone Alcohol) Acid generator: PAG-1 Quencher: Q-1 [ka]

[0269] (2) EUV lithography evaluation Each resist material shown in Table 1 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a thickness of 20 nm, and the resist film was pre-baked for 60 seconds at 105°C using a hot plate to produce a resist film with a thickness of 50 nm. This was exposed using an EUV scanner NXE3300 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, a hole pattern mask with a pitch of 46 nm on the wafer and a +20% bias), and PEB was performed for 60 seconds on a hot plate at the temperature shown in Table 1, and development was performed for 30 seconds with a 2.38% by mass TMAH aqueous solution to obtain a hole pattern with a dimension of 23 nm. The exposure dose when the hole dimension was 23 nm was measured and this was taken as the sensitivity. The dimensions of 50 holes were measured using a critical dimension SEM (CG5000) manufactured by Hitachi High-Technologies Corporation, and the standard deviation (σ) calculated from the results was tripled (3σ) to take the dimensional variation (CDU). The results are shown in Table 1.

[0270] [Table 1]

[0271] The results shown in Table 1 show that the positive resist material of the present invention, which contains a polymer including a repeating unit having an ammonium salt structure of a sulfonamide having an aromatic ring substituted with an iodine atom, has sufficient sensitivity and satisfies CDU.

Claims

1. A chemically amplified positive resist material comprising: a base polymer including a repeating unit a having an ammonium salt structure of a sulfonamide having an aromatic ring substituted with an iodine atom; and at least one selected from a repeating unit b1 in which the hydrogen atom of a carboxy group is substituted with an acid labile group and a repeating unit b2 in which the hydrogen atom of a phenolic hydroxy group is substituted with an acid labile group; and a photoacid generator.

2. A chemically amplified positive resist material comprising: a repeating unit a having an ammonium salt structure of a sulfonamide having an aromatic ring substituted with an iodine atom; at least one selected from a repeating unit b1 in which a hydrogen atom of a carboxy group is substituted with an acid labile group; and a repeating unit b2 in which a hydrogen atom of a phenolic hydroxy group is substituted with an acid labile group; and a base polymer including a repeating unit represented by any of the following formulas (d1) to (d3): 【Chemistry 1】 (In the formula, each R A is independently a hydrogen atom or a methyl group. Z 1 is 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 -. Z 11 is 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-, -Z 31 -O-, or -Z 31 -O-C(═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, an ester bond, an ether bond, a bromine atom, or an iodine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group or a carbonyl group. Z 5 is a single bond, a methylene group, an ethylene group, a phenylene 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 -. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene 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 or a hydroxy group. R 21 to R 28 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. In addition, R 23 and R 24 or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. M- is a non-nucleophilic counter ion.

3. 3. The chemically amplified positive resist material according to claim 1, wherein the repeating unit a is represented by the following formula (a): 【Chemistry 2】 (In the formula, m is an integer of 1 to 5, n is an integer of 0 to 3, provided that 1≦m+n≦5, p is 1 or 2, and q is 1 or 2. R A is a hydrogen atom or a methyl group. X 1A is a single bond, an ester bond or an amide bond. X 1B is a single bond or a (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms, and the hydrocarbon group may contain an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone group, a lactam group, a carbonate bond, a halogen atom, a hydroxy group, or a carboxy group. R 1 , R 2 and R 3 are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms; R 1 and R 2 Or R 1 and X 1B may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and the ring may contain an oxygen atom, a sulfur atom, a nitrogen atom or a double bond. R 4 represents a hydroxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 7 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxycarbonyl group having 2 to 7 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms which may be substituted with a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, -N(R 4A )-C(=O)-R 4B Or -N(R 4A )-C(=O)-O-R 4B It is. 4A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 4B is a saturated hydrocarbyl group having 1 to 6 carbon atoms, an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms. R 5 is a (q+1)-valent hydrocarbon group having 1 to 10 carbon atoms. R 6 is a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms or a fluorinated aryl group having 6 to 10 carbon atoms. L 1 is a single bond, an ether bond, a carbonyl group, an ester bond, an amide bond, a carbonate bond, or a hydrocarbylene group having 1 to 20 carbon atoms, and the hydrocarbylene group may contain an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, or a carboxy group.

4. 4. The chemically amplified positive resist material according to claim 1, wherein the repeating unit b1 is represented by the following formula (b1), and the repeating unit b2 is represented by the following formula (b2): 【Chemistry 3】 (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 is an acid labile group. R 13 represents a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 6 carbon atoms, a halogen atom, a nitro group, or a cyano group. R 14 represents a single bond or a saturated hydrocarbylene group having 1 to 6 carbon atoms, some of whose carbon atoms may be substituted with ether bonds or ester bonds. a is 1 or 2. b is an integer from 0 to 4, provided that 1≦a+b≦5.

5. 2. The chemically amplified positive resist material according to claim 1, wherein the photoacid generator generates a sulfonic acid, a sulfonimide or a sulfonmethide.

6. The chemically amplified positive resist composition according to any one of claims 1 to 5, further comprising an organic solvent.

7. 7. The chemically amplified positive resist material according to claim 1, further comprising a dissolution inhibitor.

8. 8. The chemically amplified positive resist composition according to claim 1, further comprising a surfactant.

9. A pattern formation method comprising the steps of: forming a resist film on a substrate using the chemically amplified positive resist material according to any one of claims 1 to 8; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

10. 10. The method for forming a pattern according to claim 9, wherein the high-energy radiation is an ArF excimer laser beam having a wavelength of 193 nm or a KrF excimer laser beam having a wavelength of 248 nm.

11. 10. The pattern forming method according to claim 9, wherein the high energy beam is an electron beam or extreme ultraviolet light having a wavelength of 3 to 15 nm.

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