Positive resist material and pattern forming method

Abstract

To provide a positive resist material that exhibits higher sensitivity and resolution than those of the conventional ones and has low edge roughness and small size variation, and forms a pattern of good profile after exposure, and to provide a pattern forming process.SOLUTION: A positive resist material comprises a base polymer comprising a repeat unit a having the structure of a sulfonium salt of a fluorinated phenol compound.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. This is because 5G high-speed communications and artificial intelligence (AI) are becoming more widespread, and high-performance devices are needed to process these. The most advanced miniaturization technology is extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm, which is used to mass-produce 5 nm node devices. Furthermore, studies are underway to use EUV lithography for next-generation 3 nm node devices and the next-next generation 2 nm node devices.

[0003] As miniaturization progresses, image blurring due to acid diffusion has become a problem. In order to ensure resolution in fine patterns with dimensions of 45 nm or less, it has been proposed that not only improving the dissolution contrast, as has been proposed in the past, but also controlling acid diffusion is important (Non-Patent Document 1). However, since chemically amplified resist materials increase sensitivity and contrast by acid diffusion, if you try to suppress acid diffusion to the maximum extent possible by lowering the post-exposure bake (PEB) temperature or shortening the time, the sensitivity and contrast will decrease significantly.

[0004] The triangle trade-off relationship between sensitivity, resolution, and edge roughness (LWR) is shown. In order to improve the resolution, it is necessary to suppress the acid diffusion, but the sensitivity decreases as the acid diffusion distance becomes shorter.

[0005] It is effective to suppress acid diffusion by adding an acid generator that generates a bulky acid. Therefore, it has been proposed to incorporate repeating units derived from an onium salt having a polymerizable unsaturated bond into a polymer. In this case, the polymer also functions as an acid generator (polymer-bound acid generator). Patent Document 1 proposes sulfonium salts and iodonium salts having a polymerizable unsaturated bond that generate specific sulfonic acids. Patent Document 2 proposes sulfonium salts in which sulfonic acids are directly linked to the main chain.

[0006] In order to suppress acid diffusion, a polymer-bound quencher resist material has been proposed that uses a base polymer containing a sulfonium salt structure of a weak acid having a pKa of -0.8 or more and a polymerizable group (Patent Document 3). Here, carboxylic acids, sulfonamides, phenols, hexafluoroalcohols, etc. are listed as weak acids. In general, phenols and hexafluoroalcohols have too weak an acidity, are less stable as sulfonium salts, and are difficult to synthesize. In addition, resist materials that use base polymers containing a sulfonium salt structure of a weak acid have problems such as large swelling in an alkaline developer, which causes poor dimensional uniformity (CDU) of contact hole patterns due to swelling during development, and prone to pattern collapse after line and space pattern formation. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2006-045311 A [Patent Document 2] JP 2006-178317 A [Patent Document 3] International Publication No. 2019 / 167737 [Non-patent literature]

[0008] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) Summary of the Invention [Problem to be solved by the invention]

[0009] 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 that has sensitivity and resolution superior to conventional positive resist materials, has small edge roughness and dimensional variation, and produces a good pattern shape after exposure, and a pattern formation method thereof. [Means for solving the problem]

[0010] The present inventors have conducted extensive research to obtain a positive resist material that meets the recent demand for high resolution and has low edge roughness and dimensional variation, and as a result have found that to achieve this, it is necessary to shorten the acid diffusion distance to the utmost and to make the acid diffusion distance uniform at the molecular level. They have found that using a polymer that includes a repeating unit having a sulfonium salt structure of a fluorinated phenol as the base polymer makes acid diffusion extremely small, and has two effects: the acid diffusion distance is made uniform by suppressing aggregation of sulfonium salts that act as quenchers due to the repulsion of fluorine atoms, and the contrast is improved by the disappearance of the quencher in the exposed area due to the photodecomposition reaction of the sulfonium salt. This makes the base polymer effective for chemically amplified positive resist materials that have good edge roughness and dimensional variation.

[0011] Furthermore, it has been found that by introducing 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 alkali dissolution rate contrast before and after exposure, a high effect of suppressing acid diffusion, high resolution, and excellent pattern shape after exposure with little edge roughness or dimensional variation, and which is particularly suitable as a fine pattern forming material for use in the manufacture of VLSIs or for photomasks, and has been completed according to this finding.

[0012] 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 a sulfonium salt structure of a fluorinated phenol compound. 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, R A is a hydrogen atom or a methyl group. X 1 is a single bond, an ester bond, an ether bond, a phenylene group, or a naphthylene group. X 2 represents a single bond, a saturated hydrocarbylene group having 1 to 12 carbon atoms, or a phenylene group, and the saturated hydrocarbylene group may contain an ether bond, an ester bond, an amide bond, a lactone ring, or a sultone ring. X 3 is a single bond, an ester bond or an ether bond. Rf is a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group or a trifluoromethylthio group. R 1 is an alkyl group having 1 to 4 carbon atoms. R 2 ~R 4 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 2 and R 3 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. m is an integer from 1 to 4, and n is an integer from 0 to 3, provided that 1≦m+n≦4. 3. The positive resist material of 1 or 2, wherein the base polymer further comprises a repeating unit b1 in which a hydrogen atom of a carboxy group is substituted with an acid labile group and / or a repeating unit b2 in which a hydrogen atom of a phenolic hydroxy group is substituted with an acid labile group. 4. A positive resist material according to 3, 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 1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing an ester bond, an ether bond, or a lactone ring. Y 2 is a single bond, an ester bond or an amide bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid labile group. R 13 is a fluorine atom, a trifluoromethyl group, a cyano group or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is 1 or 2, and b is an integer from 0 to 4, provided that 1≦a+b≦5. 5. The positive resist material of any one of 1 to 4, wherein the base polymer further contains 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-. 6. The positive resist material of any one of 1 to 5, 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 Aare 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 groups, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. 11 represents 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 an aliphatic 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, a halogen atom, or a hydroxy group. R 21 ~R 28are each independently a halogen atom or 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. 7. A positive resist material according to any one of 1 to 6, further comprising an acid generator. 8. A positive resist material according to any one of 1 to 7, further comprising an organic solvent. 9. A positive resist material according to any one of 1 to 8, further comprising a quencher. 10. A positive resist material according to any one of 1 to 9, further comprising a surfactant. 11. 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 claims 1 to 10, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer. 12. The pattern formation method according to 11, wherein the high energy beam is an i-line, a KrF excimer laser beam, an ArF excimer laser beam, an electron beam (EB) or an EUV beam having a wavelength of 3 to 15 nm. Effect of the Invention

[0013] The positive resist material of the present invention can increase the decomposition efficiency of the acid generator, so it has a high effect of suppressing the diffusion of acid, high sensitivity, high resolution, and has small and good pattern shape, edge roughness, and dimensional variation after exposure. 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

[0014] [Base polymer] The resist material of the present invention is characterized in that it contains a base polymer that includes a repeating unit a having a sulfonium salt structure of a fluorine-substituted phenol compound.

[0015] The repeating unit a is preferably one represented by the following formula (a). [ka]

[0016] In formula (a), R A is a hydrogen atom or a methyl group.

[0017] In formula (a), X 1 is a single bond, an ester bond, an ether bond, a phenylene group, or a naphthylene group.

[0018] In formula (a), X 2 X is a single bond, a saturated hydrocarbylene group having 1 to 12 carbon atoms, or a phenylene group, and the saturated hydrocarbylene group may contain an ether bond, an ester bond, an amide bond, a lactone ring, or a sultone ring. 2The hydrocarbylene group represented by the formula (I) may be linear, branched or cyclic, and 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 alkanediyl groups having 1 to 12 carbon atoms, such as a-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, and decane-1,10-diyl group; cyclic saturated hydrocarbylene groups having 3 to 12 carbon atoms, such as a cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group; and groups obtained by combining these.

[0019] In formula (a), X 3 is a single bond, an ester bond or an ether bond.

[0020] In formula (a), Rf is a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group, or a trifluoromethylthio group.

[0021] In formula (a), R 1 is an alkyl group having 1 to 4 carbon atoms.

[0022] In formula (a), R 2 ~R 4 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 2 and R 3 may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0023] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0024] R 2 ~R 4The 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 of such alkyl groups 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 having 2 to 20 carbon atoms, such as a vinyl group, a propenyl group, a butenyl group, or a hexenyl group; and an ethynyl group. alkynyl groups having 2 to 20 carbon atoms, such as a propynyl group or a butynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexenyl group or a norbornenyl group; aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, 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 or a tert-butylnaphthyl group; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group or a phenethyl group; and groups obtained by combining these.

[0025] In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0026] Also, R 2 and R 3 and 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 4 It is a bond with .)

[0027] In formula (a), m is an integer of 1 to 4, and n is an integer of 0 to 3, provided that 1≦m+n≦4.

[0028] Examples of the anion of the monomer that gives the repeating unit a include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] Examples of the sulfonium cation of the monomer that provides the repeating unit a include, but are not limited to, those shown below. [ka]

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041]

change

[0042]

change

[0043]

change

[0044]

change

[0045]

change

[0046]

change

[0047]

change

[0048]

change

[0049]

change

[0050]

change

[0051]

change

[0052] [ka]

[0053] [ka]

[0054] [ka]

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] The sulfonium cation is decomposed by photolysis to become a fluorinated phenol group bonded to the polymer. The fluorinated phenol group has the characteristic of swelling less in an alkaline developer than weak acid groups such as carboxylic acid, sulfonamide, and hexafluoroalcohol. This characteristic improves the CDU of the contact hole pattern, reduces the stress applied to the pattern during spin drying for drying after rinsing with pure water of the line and space pattern, and reduces the pattern collapse after pattern formation.

[0059] The repeating unit a is a quencher having a sulfonium salt structure of a fluorinated phenol compound, and is a quencher-bound polymer. The quencher-bound polymer has a high effect of suppressing acid diffusion, and is characterized by excellent resolution as described above. At the same time, since the repeating unit a has fluorine atoms, the quenchers do not aggregate due to the repulsion of the negatively charged fluorine atoms, and the acid diffusion distance is uniform. Furthermore, secondary electrons are generated during exposure due to the absorption of fluorine atoms, and the decomposition of the acid generator is promoted, thereby increasing the sensitivity. This makes it possible to simultaneously achieve high sensitivity, high resolution, low LWR, and low CDU.

[0060] In order to enhance the dissolution contrast, the base polymer may contain a repeating unit in which the hydrogen atom of a carboxy group is substituted with an acid labile group (hereinafter also referred to as repeating unit b1), and / or a repeating unit in which the hydrogen atom of a phenolic hydroxy group is substituted with an acid labile group (hereinafter also referred to as repeating unit b2).

[0061] Examples of the repeating units b1 and b2 include those represented by the following formulae (b1) and (b2), respectively. [ka]

[0062] In formulas (b1) and (b2), R A Each of Y is independently a hydrogen atom or a methyl group. 1 Y is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing an ester bond, an ether bond, or a lactone ring. 2 is a single bond, an ester bond or an amide bond. 3 R is a single bond, an ether bond or an ester bond. 11 and R 12 R is each independently an acid labile group. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 14is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4, provided that 1≦a+b≦5.

[0063] 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]

[0064] [ka]

[0065] 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]

[0066] 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.)

[0067] In formula (AL-1), c is an integer of 0 to 6. L1is 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.

[0068] R L1 The 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.

[0069] 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.

[0070] 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.)

[0071] 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.

[0072] In formula (AL-2), R L2 and R L3are 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, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, and an n-octyl group.

[0073] 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.)

[0074] R L2 and R L3 And, R L2 and R L4 and, or R L3 and 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.

[0075] 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]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] 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.

[0080] 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.)

[0081] 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 L12may 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.

[0082] 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, a portion of -CH2- in these groups may be substituted with a group containing a hetero atom, and a portion of the hydrogen atoms in 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-.

[0083] 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.)

[0084] In formula (AL-3), R L5 , R L6 and R L7are 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 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.

[0085] 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.

[0086] 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.)

[0087] 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. L16R 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.

[0088] 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.)

[0089] 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.

[0090] 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]

[0091] 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 Lc11are 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 means that adjacent carbon atoms may be bonded to each other without any intermediate bond to form a double bond. Note that this formula also represents an enantiomer.

[0092] Here, examples of the monomer 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, R A is the same as above. [ka]

[0093] 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]

[0094] 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.

[0095] Examples of the monomer represented by formula (AL-3)-23 include, but are not limited to, those shown below. In the following formula, R A is the same as above, Ac is an acetyl group, and Me is a methyl group. [ka]

[0096] [ka]

[0097] In addition to the above acid labile groups, acid labile groups containing aromatic groups as described in Japanese Patent Nos. 5,565,293, 5,434,983, 5,407,941, 5,655,756 and 5,655,755 can also be used.

[0098] 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-.

[0099] 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]

[0100] [ka]

[0101] [ka]

[0102] [ka]

[0103] [ka]

[0104] [ka]

[0105] [ka]

[0106] [ka]

[0107] [ka]

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] 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]

[0112] 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 groups, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. 11Z 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 31 Z is an aliphatic 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. 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 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, a halogen atom, or a hydroxyl group. 1 , Z 11 , Z 31 and Z 51 The aliphatic hydrocarbylene group represented by the formula (I) may be saturated or unsaturated and may be linear, branched or cyclic.

[0113] 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 halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 2 ~R4 Examples of the examples are similar to those given in the description of .

[0114] 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 is as defined in the description of formula (1-1) below, 101 and R 102 and the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0115] 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.

[0116] 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]

[0117] 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.

[0118] In formula (d1-2), R 32 is 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.

[0119] 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]

[0120] Specific examples of the cation of the monomer which gives the repeating unit d2 or d3 include the same as those exemplified as the sulfonium cation of the monomer which gives the repeating unit a.

[0121] 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.

change

[0122]

change

[0123]

change

[0124]

change

[0125]

change

[0126]

change

[0127]

change

[0128]

change

[0129]

change

[0130]

change

[0131]

change

[0132] [ka]

[0133] [ka]

[0134] [ka]

[0135] 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]

[0136] 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 caused by acid diffusion can be prevented. Furthermore, the acid generator is uniformly dispersed, improving LWR and CDU. When a base polymer containing the repeating units d1 to d3 (i.e., a polymer-bound acid generator) is used, the incorporation of an additive acid generator, which will be described later, can be omitted.

[0137] 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]

[0138] [ka]

[0139]

Chem.

[0140] 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, coumarone, etc.

[0141] 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; still 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.

[0142] To synthesize the base polymer, for example, monomers that provide the repeating units described above may be heated in an organic solvent with the addition of a radical polymerization initiator to perform polymerization.

[0143] Examples of the organic solvent used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The temperature during polymerization is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, and more preferably 5 to 20 hours.

[0144] When a monomer containing a hydroxy group is copolymerized, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid, such as an ethoxyethoxy group, during polymerization, and then deprotected with a weak acid and water after polymerization; alternatively, the hydroxy group may be substituted with an acetyl group, a formyl group, a pivaloyl group, or the like, and then subjected to alkaline hydrolysis after polymerization.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] The base polymer may include two or more polymers having different composition ratios, Mw, or Mw / Mn. Also, a polymer including the repeating unit a may be blended with a polymer not including the repeating unit a but including the repeating units b1 and / or b2.

[0150] [Acid generator] The positive resist material of the present invention may contain an acid generator that generates a strong acid (hereinafter, also referred to as an additive acid generator). The strong acid here means a compound that has sufficient acidity to cause a deprotection reaction of the acid labile group of the base polymer.

[0151] 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 when irradiated 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 JP2008-111103A.

[0152] 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]

[0153] In formulas (1-1) and (1-2), R 101 ~R 105 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be linear, branched or cyclic. Specific examples thereof include R 2 ~R 4 Examples of the hydrocarbyl group include those exemplified in the description of . In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like. 101 and R 102 and 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 rings described in the explanation of formula (a) as R 2 and R 3 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.

[0154] Examples of the cation of the sulfonium salt represented by formula (1-1) include the same as those exemplified as the sulfonium cation of the monomer that gives the repeating unit a.

[0155] Examples of the cation of the iodonium salt represented by formula (1-2) include, but are not limited to, those shown below. [ka]

[0156] [ka]

[0157] In formulas (1-1) and (1-2), Xa - is an anion selected from the following formulas (1A) to (1D). [ka]

[0158] 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.

[0159] The anion represented by formula (1A) is preferably one represented by the following formula (1A'). [ka]

[0160] 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.

[0161] 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, an n-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, and a norbornyl group. cyclic saturated hydrocarbyl groups having 3 to 38 carbon atoms, such as a norbornylmethyl group, a tricyclodecanyl group, a tetracyclododecanyl group, a tetracyclododecanylmethyl group, or a dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 38 carbon atoms, such as an allyl group or a 3-cyclohexenyl group; aryl groups having 6 to 38 carbon atoms, such as a phenyl group, a 1-naphthyl group, or a 2-naphthyl group; aralkyl groups having 7 to 38 carbon atoms, such as a benzyl group or a diphenylmethyl group; and groups obtained by combining these.

[0162] In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, so that the hydrocarbyl group may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. Examples of the hydrocarbyl group containing a heteroatom 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] 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.

[0171] As the photoacid generator, a compound represented by the following formula (2) can also be suitably used. [ka]

[0172] 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 the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0173] 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 a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, or an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, a 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 the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0174] 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 the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH2- of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, so that the hydrocarbylene group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. As the heteroatom, an oxygen atom is preferable.

[0175] 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 formula (I) include the same as those exemplified above.

[0176] 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.

[0177] In the formula (2), t is an integer of 0 to 3.

[0178] The photoacid generator represented by formula (2) is preferably one represented by the following formula (2'). [ka]

[0179] 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.

[0180] 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.

[0181] 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.

[0182] The photoacid generator may be a sulfonium salt or an iodonium salt containing an anion having 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]

[0183] In formulas (3-1) and (3-2), p is an integer satisfying 1≦p≦3. q and r are integers satisfying 1≦q≦5, 0≦r≦3, and 1≦q+r≦5. q is preferably an integer satisfying 1≦q≦3, more preferably 2 or 3. r is preferably an integer satisfying 0≦r≦2.

[0184] In formulas (3-1) and (3-2), X BI represents an iodine atom or a bromine atom, and when p and / or q are 2 or more, they may be the same or different.

[0185] In formulas (3-1) and (3-2), L 1 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.

[0186] In formulas (3-1) and (3-2), L 2represents a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and represents a (p+1)-valent linking group having 1 to 20 carbon atoms when p is 2 or 3, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0187] 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 hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms or a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond, or 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D Or -N(R 401C )-C(=O)-OR 401D R 401A and R 401B 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 12 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 may be the same or different from each other.

[0188] 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.

[0189] 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.

[0190] 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 the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the -CH2- of the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate ester bond. 402 and R 403 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is as defined in the description of formula (1-1) as R 101 and R 102 and the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0191] 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).

[0192] 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]

[0193] [ka]

[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]

change

[0211]

change

[0212]

change

[0213]

change

[0214]

change

[0215] When the positive resist material of the present invention contains an additive acid generator, the content thereof is preferably from 0.1 to 50 parts by mass, and more preferably from 1 to 40 parts by mass, relative to 100 parts by mass of the base polymer. By including repeating units d1 to d3 in the base polymer and / or by including an additive acid generator, the positive resist material of the present invention can function as a chemically amplified positive resist material.

[0216] [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 monoethyl ether. Examples of the monomer units include ethers such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, and the like; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate (a mixture of L-, D-, and DL-isomers), ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol mono tert-butyl ether acetate, and the like; and lactones such as γ-butyrolactone, and the like.

[0217] 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.

[0218] [Other ingredients] The positive resist composition of the present invention may contain, in addition to the above-mentioned components, a surfactant, a dissolution inhibitor, a quencher, a water repellency enhancer, acetylene alcohols, and the like.

[0219] 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.

[0220] By blending a dissolution inhibitor in the positive resist material of the present invention, 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 containing 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, hydroxyl groups of cholic acid, and compounds in which hydrogen atoms of carboxyl groups are substituted with acid labile groups, and the like, and are described, for example, in paragraphs

[0155] to

[0178] of JP-A-2008-122932.

[0221] When the positive resist composition of the present invention contains the dissolution inhibitor, the content thereof 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.

[0222] 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.

[0223] 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 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.

[0224] Another example of the quencher is a polymer-type quencher described in JP 2008-239918 A. This quencher 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.

[0225] When the positive resist composition of the present invention contains the quencher, the content thereof is preferably 0 to 5 parts by mass, and more preferably 0 to 4 parts by mass, relative to 100 parts by mass of the base polymer. The quencher may be used alone or in combination of two or more kinds.

[0226] The water repellency improver improves the water repellency of the resist film surface, and 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 the 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 the acid in the PEB and preventing the opening failure of the hole pattern after development. When the positive resist composition of the present invention contains a water repellency improver, the content thereof is preferably 0 to 20 parts by mass, and 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.

[0227] The acetylene alcohols include those described in paragraphs

[0179] to

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

[0228] [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.

[0229] 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.

[0230] 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. 2Approximately, 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 2 The 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.

[0231] 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.

[0232] After exposure or PEB, the exposed resist film is developed using a developer of an alkaline aqueous solution of 0.1 to 10 mass %, preferably 2 to 5 mass %, such as 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 portions are dissolved in the developer, while the unexposed portions are not dissolved, and the desired positive pattern is formed on the substrate.

[0233] The positive resist material can also be used to carry out 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.

[0234] 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.

[0235] 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.

[0236] 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.

[0237] 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.

[0238] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0239] 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.

[0240] 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

[0241] 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.

[0242] [1] Synthesis of monomer [Synthesis Example 1] The following monomers M-1 to M-11 and comparative monomer cM-1 were obtained by ion exchange between a sulfonium salt chloride and a fluorophenol compound or a carboxylic acid compound having a polymerizable double bond. [ka]

[0243] [ka]

[0244] [2] Synthesis of base polymer Monomers AM-1 to AM-4 and PM-1 to PM-3 used in the synthesis of the base polymer are as follows: The Mw of the polymer is a polystyrene-equivalent measured value by GPC using THF as a solvent. [ka]

[0245] [ka]

[0246] [Synthesis Example 2-1] Synthesis of Polymer P-1 In a 2L flask, 2.3g of monomer 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 polymer P-1 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0247] [Synthesis Example 2-2] Synthesis of Polymer P-2 In a 2L flask, 2.4g of monomer M-2, 7.3g of 1-methyl-1-cyclohexyl methacrylate, 4.8g of 4-hydroxystyrene, 11.0g of monomer 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 polymer P-2 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0248] [Synthesis Example 2-3] Synthesis of Polymer P-3 In a 2L flask, 2.7g of monomer M-3, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.6g of 3-hydroxystyrene, 11.9g of monomer 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 polymer P-3 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0249] [Synthesis Example 2-4] Synthesis of polymer P-4 In a 2L flask, 3.0g of monomer M-4, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.6g of 3-hydroxystyrene, 10.6g of monomer 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 polymer P-4 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0250] [Synthesis Example 2-5] Synthesis of Polymer P-5 In a 2L flask, 2.9g of monomer M-5, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.6g of 3-hydroxystyrene, 11.0g of monomer 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 polymer P-5 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0251] [Synthesis Example 2-6] Synthesis of Polymer P-6 In a 2L flask, 2.9g of monomer M-6, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.6g of 4-hydroxystyrene, 10.6g of monomer 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-6. The composition of polymer P-6 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0252] [Synthesis Example 2-7] Synthesis of polymer P-7 In a 2L flask, 3.3g of monomer M-7, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.6g of 3-hydroxystyrene, 11.0g of monomer 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 polymer P-7 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0253] [Synthesis Example 2-8] Synthesis of Polymer P-8 In a 2L flask, 2.3g of monomer M-8, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 3.6g of 3-hydroxystyrene, 11.0g of monomer 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 polymer P-8 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0254] [Synthesis Example 2-9] Synthesis of Polymer P-9 In a 2L flask, 2.9g of monomer M-5, 8.9g of monomer AM-1, 4.8g of 4-hydroxystyrene, 11.0g of monomer 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 polymer P-9 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0255] [Synthesis Example 2-10] Synthesis of Polymer P-10 In a 2L flask, 3.3g of monomer M-7, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 4.8g of 3-hydroxystyrene, 3.4g of monomer 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 polymer P-10 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0256] [Synthesis Example 2-11] Synthesis of Polymer P-11 In a 2L flask, 1.2g of monomer M-5, 8.4g of 1-methyl-1-cyclopentyl methacrylate, 4.0g of 3-hydroxystyrene, 11.0g of monomer 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 polymer P-11 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0257] [Synthesis Example 2-12] Synthesis of Polymer P-12 In a 2L flask, 2.9g of monomer M-9, 11.1g of AM-2, 3.6g of 3-hydroxystyrene, 11.0g of monomer 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 polymer P-12 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0258] [Synthesis Example 2-13] Synthesis of Polymer P-13 In a 2L flask, 2.9g of monomer M-10, 11.7g of AM-3, 3.6g of 3-hydroxystyrene, 11.0g of monomer 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-13. The composition of polymer P-13 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0259] [Synthesis Example 2-14] Synthesis of Polymer P-14 In a 2L flask, 2.5g of monomer M-11, 10.8g of AM-4, 3.6g of 3-hydroxystyrene, 11.0g of monomer 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-14. The composition of polymer P-14 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0260] [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 comparative monomer cM-1 was used instead of monomer M-1. The composition of comparative polymer cP-1 was 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0261] [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 monomer M-1 was not used. The composition of comparative polymer cP-2 was 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0262] [Comparative Synthesis Example 3] Synthesis of Comparative Polymer cP-3 Comparative polymer cP-3 was obtained in the same manner as in Synthesis Example 2-5, except that monomer M-5 was not used. The composition of comparative polymer cP-3 was 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0263] [3] Preparation and evaluation of positive resist materials [Examples 1 to 17, Comparative Examples 1 to 4] (1) Preparation of positive resist material A solution in which each component was dissolved in a solvent containing 50 ppm of Omnova's surfactant PolyFox PF-636, in the composition shown in Table 1, was filtered through a 0.2 μm filter to prepare a positive resist material.

[0264] In Table 1, the components are as follows: Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (Diacetone Alcohol) EL (L-ethyl lactate)

[0265] Acid generator: PAG-1 [ka]

[0266] Quencher: Q-1, Q-2, cQ-1 [ka]

[0267] (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 substrate was pre-baked at 105°C for 60 seconds using a hot plate to produce a resist film with a thickness of 60 nm. The resist film was exposed to light using an EUV scanner NXE3400 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, a mask with a hole pattern with a pitch of 46 nm on the wafer and a +20% bias), and PEB was performed on a hot plate at the temperature shown in Table 1 for 60 seconds, 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 dimensions were each 23 nm was measured and used as the sensitivity. The dimensions of 50 holes were also measured using a Hitachi High-Technologies Corporation CD-SEM (CG5000), and the CDU was calculated as three times the standard deviation (σ) (3σ). The results are shown in Table 1.

[0268] [Table 1]

[0269] The results shown in Table 1 demonstrate that the positive resist material using the polymer containing a repeating unit having a sulfonium salt structure of a fluorinated phenol compound of the present invention has sufficient sensitivity and satisfies CDU.

Claims

1. A positive resist material comprising a base polymer containing a repeating unit a having a sulfonium salt structure of a fluorinated phenol compound.

2. 2. The positive resist material according to claim 1, wherein the repeating unit a is represented by the following formula (a): 【Chemistry 1】 (In the formula, R A is a hydrogen atom or a methyl group. X 1 is a single bond, an ester bond, an ether bond, a phenylene group, or a naphthylene group. X 2 represents a single bond, a saturated hydrocarbylene group having 1 to 12 carbon atoms, or a phenylene group, and the saturated hydrocarbylene group may contain an ether bond, an ester bond, an amide bond, a lactone ring, or a sultone ring. X 3 is a single bond, an ester bond or an ether bond. Rf is a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group or a trifluoromethylthio group. R 1 is an alkyl group having 1 to 4 carbon atoms. R 2 ~R 4 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 2 and R 3 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. m is an integer from 1 to 4. n is an integer from 0 to 3, provided that 1≦m+n≦4.

3. 3. The positive resist material according to claim 1, wherein the base polymer further comprises a repeating unit b1 in which a hydrogen atom of a carboxy group is substituted with an acid labile group and / or a repeating unit b2 in which a hydrogen atom of a phenolic hydroxy group is substituted with an acid labile group.

4. 4. The positive resist material according to claim 3, 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 2】 (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 which includes a single bond, a phenylene group, a naphthylene group, an ester bond, an ether bond, or a lactone ring. Y 2 is a single bond, an ester bond or an amide bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid labile group. R 13 is a fluorine atom, a trifluoromethyl group, a cyano group or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is 1 or 2. b is an integer from 0 to 4, provided that 1≦a+b≦5.

5. The positive resist material according to any one of claims 1 to 4, wherein the base polymer further comprises a repeating unit c containing an adhesive group selected from the group consisting of 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, -O-C(=O)-S-, and -O-C(=O)-NH-.

6. The positive resist material according to any one of claims 1 to 5, wherein the base polymer further comprises a repeating unit represented by any one of the following formulas (d1) to (d3): 【Chemistry 3】 (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 -O-Z 11 -, -C(=O)-O-Z 11 - or -C(=O)-NH-Z 11 - is. 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -O-C(=O)-. Z 31 represents an aliphatic 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, which 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 represents 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 - 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, a halogen atom, or a hydroxy group. R 21 ~R 28 are each independently a halogen atom or 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.)

7. The positive resist composition according to any one of claims 1 to 6, further comprising an acid generator.

8. The positive resist composition according to any one of claims 1 to 7, further comprising an organic solvent.

9. The positive resist material according to any one of claims 1 to 8, further comprising a quencher.

10. The positive resist material according to any one of claims 1 to 9, further comprising a surfactant.

11. A pattern forming method comprising the steps of: forming a resist film on a substrate using the positive resist material according to any one of claims 1 to 10; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

12. 12. The method for forming a pattern according to claim 11, wherein the high energy beam is i-beam, KrF excimer laser beam, ArF excimer laser beam, electron beam or extreme ultraviolet ray having a wavelength of 3 to 15 nm.

Images