Resist material and pattern forming method

Abstract

To provide a resist material which exhibits high sensitivity and improved LWR and CDU regardless of whether it is positive or negative, and a pattern forming method using the same.SOLUTION: The resist material contains a quencher containing a sulfonium salt of an aromatic carboxylic acid having a nitrogen atom-containing cyclic group and a benzene ring substituted with a nitro group.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a 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] The acid labile group used in the (meth)acrylate polymer for ArF resist material undergoes a deprotection reaction by using a photoacid generator that generates a sulfonic acid substituted with a fluorine atom at the α-position, but does not proceed with an acid generator that generates a sulfonic acid or carboxylic acid not substituted with a fluorine atom at the α-position. When a sulfonium salt or iodonium salt that generates a sulfonic acid not substituted with a fluorine atom at the α-position is mixed with a sulfonium salt or iodonium salt that generates a sulfonic acid not substituted with a fluorine atom at the α-position, the sulfonium salt or iodonium salt that generates a sulfonic acid not substituted with a fluorine atom at the α-position undergoes ion exchange with the sulfonic acid not substituted with a fluorine atom at the α-position. The sulfonic acid generated by light and substituted with a fluorine atom at the α-position reverts to a sulfonium salt or iodonium salt by ion exchange, so the sulfonium salt or iodonium salt of the sulfonic acid or carboxylic acid not substituted with a fluorine atom at the α-position functions as a quencher. A resist material has been proposed that uses a sulfonium salt or an iodonium salt that generates a carboxylic acid as a quencher (Patent Document 3).

[0007] A resist material has been proposed that uses a sulfonium salt of a carboxylic acid bonded to an amino group having a cyclic structure as a quencher (Patent Document 4). Although the sulfonium salt of a carboxylic acid bonded to an amino group having a cyclic structure is highly effective in suppressing acid diffusion, further improved control of acid diffusion is required. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2006-45311 A [Patent Document 2] JP 2006-178317 A [Patent Document 3] JP 2007-114431 A [Patent Document 4] JP 2017-58447 A [Non-patent literature]

[0009] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) Summary of the Invention [Problem to be solved by the invention]

[0010] In resist materials, it is desirable to develop a quencher that can improve the LWR of line patterns and the dimensional uniformity (CDU) of hole patterns and also improve sensitivity. To achieve this, it is necessary to further reduce image blur caused by diffusion.

[0011] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a resist material, whether positive or negative, which has high sensitivity and improved LWR and CDU, and a pattern formation method using the same. [Means for solving the problem]

[0012] As a result of intensive research into achieving the above-mentioned object, the inventors have found that a resist material to which a sulfonium salt of an aromatic carboxylic acid having a benzene ring substituted with a nitrogen-atom-containing cyclic group and a nitro group is added acts as a quencher for suppressing acid diffusion, and that the synergistic effect of the nitrogen-atom-containing cyclic group and the nitro group is highly effective in suppressing acid diffusion, and that due to the low acid diffusion, it is possible to obtain a resist material which has improved LWR and CDU, excellent resolution, and a wide process margin, and have completed the present invention.

[0013] That is, the present invention provides the following chemically amplified resist material and pattern forming method. 1. A resist material containing a quencher comprising a sulfonium salt of an aromatic carboxylic acid having a nitrogen atom-containing cyclic group and a benzene ring substituted with a nitro group. 2. The resist material according to 1, wherein the sulfonium salt is represented by the following formula (1) or (2): [ka] (In the formula, m is 1 or 2. n1 is 1 or 2, and n2 is an integer of 0 to 3, with the proviso that 1≦n1+n2≦4.) R is a heterocyclic ring having 3 to 12 carbon atoms and containing a nitrogen atom in the formula, and may contain at least one bond selected from an ether bond, an ester bond, a sulfide bond, a sulfonyl group, and -N=; R 1 and a carbon atom contained in the ring may be bonded to form a bridged ring. The circle R' is a heterocycle having 3 to 12 carbon atoms containing a nitrogen atom in the formula, and is an ether bond, an ester bond, a sulfide bond, a sulfonyl group, -N= and -N(R 1 )-. L is an ether bond, an ester bond, an amide bond or a thioester bond. X 1 and X 2are each independently a single bond or a saturated hydrocarbylene group having 1 to 20 carbon atoms, and the saturated hydrocarbylene group may contain at least one bond selected from an ether bond, an ester bond and a sulfide bond. R 1 is a hydrogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms, an acetyl group, a methoxycarbonyl group, an ethoxycarbonyl group, an n-propyloxycarbonyl group, an isopropyloxycarbonyl group, a tert-butoxycarbonyl group, a tert-pentyloxycarbonyl group, a methylcyclopentyloxycarbonyl group, an ethylcyclopentyloxycarbonyl group, a propylcyclopentyloxycarbonyl group, a phenyl group, a benzyl group, a naphthyl group, a naphthylmethyl group, a methylcyclohexyloxycarbonyl group, an ethylcyclohexyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, an allyloxycarbonyl group, a methoxymethyl group, an ethoxymethyl group, a propoxymethyl group, or a butoxymethyl group. R 2 represents a hydrogen atom, a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms, or a phenyl group, and some or all of the hydrogen atoms of the saturated hydrocarbyl group or phenyl group may be substituted with halogen atoms. R 3 is a hydrogen atom, a halogen atom, or a hydrocarbyl group having 1 to 10 carbon atoms. R 4 ~R 6 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 4 and R 5 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 3. The resist material according to 1 or 2, further comprising an acid generator that generates acid. 4. The resist material of any one of 1 to 3, wherein the acid generator generates a sulfonic acid, an imide acid or a methide acid. 5. A resist material according to any one of 1 to 4, further comprising an organic solvent. 6. A resist material according to any one of 1 to 5, further comprising a base polymer. 7. The resist material of any one of 1 to 6, wherein the base polymer contains a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 is a linking group having 1 to 12 carbon atoms and containing at least one type selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 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 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of the carbon atoms of which may be substituted with ether bonds or ester bonds. a is 1 or 2, and b is an integer from 0 to 4, provided that 1≦a+b≦5. 8. The resist material of 7, which is a chemically amplified positive resist material. 9. The resist material of any one of 1 to 6, wherein the base polymer does not contain an acid labile group. 10. The resist material of 9, which is a chemically amplified negative resist material. 11. A resist material according to any one of 1 to 10, further comprising a surfactant. 12. The resist material of any one of 1 to 11, wherein the base polymer further contains at least one repeating unit selected from those represented by the following formulas (f1) to (f3): [ka] (In the formula, RA 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 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, an iodine atom, or a bromine 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 and R 26 and R 27 and 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. 13. A pattern forming method comprising the steps of forming a resist film on a substrate using a resist material according to any one of claims 1 to 12, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer. 14. The pattern formation method according to 13, wherein the high-energy beam is KrF excimer laser light, ArF excimer laser light, an electron beam (EB) or EUV having a wavelength of 3 to 15 nm. Effect of the Invention

[0014] The sulfonium salt of aromatic carboxylic acid having a nitrogen atom-containing cyclic group and a benzene ring substituted with a nitro group is a quencher that suppresses acid diffusion. This results in low acid diffusion properties, and it is possible to improve LWR and CDU. This makes it possible to construct a resist material with small LWR and improved CDU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [Resist material] The resist material of the present invention comprises a quencher comprising a sulfonium salt of an aromatic carboxylic acid having a nitrogen atom-containing cyclic group and a benzene ring substituted with a nitro group.

[0016] [Sulfonium salts of aromatic carboxylic acids having a nitrogen atom-containing cyclic group and a benzene ring substituted with a nitro group] The sulfonium salt of an aromatic carboxylic acid having a nitrogen atom-containing cyclic group and a benzene ring substituted with a nitro group (hereinafter also referred to as sulfonium salt A) is represented by the following formula (1) or (2). [ka]

[0017] In the formulas (1) and (2), m is 1 or 2. n1 is 1 or 2, and n2 is an integer of 0 to 3, provided that 1≦n1+n2≦4.

[0018] In formula (1), R is a heterocyclic ring having 3 to 12 carbon atoms containing a nitrogen atom, and may contain at least one bond selected from an ether bond, an ester bond, a sulfide bond, a sulfonyl group, and -N=; R 1 and a carbon atom contained in the ring may be bonded to form a bridged ring. In formula (2), the circle R' is a heterocycle having 3 to 12 carbon atoms containing a nitrogen atom in the formula, and is an ether bond, an ester bond, a sulfide bond, a sulfonyl group, -N= and -N(R 1 )-.

[0019] The nitrogen atom-containing heterocycle having 3 to 12 carbon atoms may be saturated or unsaturated, and may be a monocycle or a polycycle. In the case of a polycycle, a condensed ring or a bridged ring is preferable. Specific examples of the heterocycle include an aziridine ring, an azirine ring, an azetidine ring, an azeto ring, a pyrrolidine ring, a pyrroline ring, a pyrrole ring, a piperidine ring, a tetrahydropyridine ring, a pyridine ring, an azepane ring, an azocane ring, an azanorbornane ring, an azaadamantane ring, a tropane ring, a quinuclidine ring, an oxazolidine ring, a thiazolidine ring, a morpholine ring, a thiomorpholine ring, a pyrazolidine ring, an imidazolidine ring, a pyrazoline ring, an imidazoline ring, a pyrazole ring, an imidazole ring, Preferred are a triazole ring, a tetrazole ring, a pyrazine ring, a triazine ring, an indoline ring, an indole ring, an isoindole ring, a pyrimidine ring, an indolizine ring, a benzimidazole ring, an azaindole ring, an azaindazole ring, a purine ring, a tetrahydroquinoline ring, a tetrahydroisoquinoline ring, a decahydroquinoline ring, a decahydroisoquinoline ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a phthalazine ring, a quinazoline ring, a cinnoline ring, a carbazole ring, and the like.

[0020] In formulas (1) and (2), L is an ether bond, an ester bond, an amide bond or a thioester bond.

[0021] In formulas (1) and (2), X 1 and X 2 are each independently a single bond or a saturated hydrocarbylene group having 1 to 20 carbon atoms, and the saturated hydrocarbylene group may contain at least one bond selected from an ether bond, an ester bond and a sulfide bond. 1 is preferably a single bond or a saturated hydrocarbylene group having 1 to 3 carbon atoms, and X 2 As the group, a single bond is preferable.

[0022] In formulas (1) and (2), R 1 is a hydrogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms, an acetyl group, a methoxycarbonyl group, an ethoxycarbonyl group, an n-propyloxycarbonyl group, an isopropyloxycarbonyl group, a tert-butoxycarbonyl group, a tert-pentyloxycarbonyl group, a methylcyclopentyloxycarbonyl group, an ethylcyclopentyloxycarbonyl group, a propylcyclopentyloxycarbonyl group, a phenyl group, a benzyl group, a naphthyl group, a naphthylmethyl group, a methylcyclohexyloxycarbonyl group, an ethylcyclohexyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, an allyloxycarbonyl group, a methoxymethyl group, an ethoxymethyl group, a propoxymethyl group, or a butoxymethyl group.

[0023] In formulas (1) and (2), R 2 represents a hydrogen atom, a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms, or a phenyl group, and some or all of the hydrogen atoms of the saturated hydrocarbyl group or phenyl group may be substituted with halogen atoms.

[0024] R 1 and R 2The saturated hydrocarbyl group having 1 to 6 carbon atoms represented by the formula (I) may be linear, branched or cyclic, and specific examples thereof include alkyl groups having 1 to 6 carbon atoms, such as 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 isopentyl group, a sec-pentyl group, a 3-pentyl group, a tert-pentyl group, a neopentyl group and an n-hexyl group; and alkyl groups having 3 to 6 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a cyclopropylethyl group, a cyclobutylmethyl group, a cyclobutylethyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a methylcyclopropyl group, a methylcyclobutyl group, a methylcyclopentyl group, an ethylcyclopropyl group and an ethylcyclobutyl group. 6 Examples of the cyclic saturated hydrocarbyl groups include R 2 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0025] In formula (1) or (2), R 3 R is a hydrogen atom, a halogen atom, or a hydrocarbyl group having 1 to 10 carbon atoms. 3 Examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 3The 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 10 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 isopentyl group, a sec-pentyl group, a 3-pentyl group, a tert-pentyl group, a neopentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, or an n-decyl group; a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a norbornyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl ... cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms, such as a cyclopropylmethyl group, a cyclopropylethyl group, a cyclobutylmethyl group, a cyclobutylethyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a methylcyclopropyl group, a methylcyclobutyl group, a methylcyclopentyl group, a methylcyclohexyl group, an ethylcyclopropyl group, an ethylcyclobutyl group, an ethylcyclopentyl group, or an ethylcyclohexyl group; alkenyl groups having 2 to 10 carbon atoms, such as ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, and decynyl groups; alkynyl groups having 2 to 10 carbon atoms, such as ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, and decynyl groups; cyclopentenyl, cyclohexenyl, methylcyclopentenyl, methylcyclohexenyl, ethylcyclopentenyl, ethylcyclohexenyl, norbornyl, Examples of the alkyl group include cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 10 carbon atoms, such as a naphthyl group; aryl groups having 6 to 10 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, and a naphthyl group; aralkyl groups having 7 to 10 carbon atoms, such as a benzyl group, a phenethyl group, a phenylpropyl group, and a phenylbutyl group; and groups obtained by combining these groups.

[0026] Examples of the anion of the sulfonium salt represented by formula (1) or (2) include, but are not limited to, those shown below. In the following formula, R 1 is the same as above. [ka]

[0027] [ka]

[0028] [ka]

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] [ka]

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] In formulas (1) and (2), R 4 ~R 6 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0044] R 4 ~R 6 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0045] R 4 ~R 6The 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.

[0046] 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 mercapto group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0047] Also, R 4 and R 5 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 6 It is a combination with .)

[0048] Cations of the sulfonium salts represented by formulas (1) and (2) include, but are not limited to, those shown below. [ka]

[0049] [ka]

[0050] [ka]

[0051] [ka]

[0052]

change

[0053]

change

[0054]

change

[0055]

change

[0056]

change

[0057]

change

[0058]

change

[0059]

change

[0060]

change

[0061]

change

[0062]

change

[0063] [ka]

[0064] [ka]

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] The sulfonium salt A can be synthesized, for example, by ion exchange of a hydrochloride or carbonate having a sulfonium cation with an aromatic carboxylic acid having a nitrogen atom-containing cyclic group and a benzene ring substituted with a nitro group.

[0073] In the resist material of the present invention, the content of the sulfonium salt A is preferably 0.001 to 50 parts by mass, and more preferably 0.01 to 40 parts by mass, relative to 100 parts by mass of the base polymer described below. The sulfonium salt A may be used alone or in combination of two or more kinds.

[0074] [Base polymer] The resist material of the present invention may contain a base polymer. In the case of a positive resist material, the base polymer contains a repeating unit containing an acid labile group. The repeating unit containing an acid labile group is preferably a repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1) or a repeating unit represented by the following formula (a2) (hereinafter also referred to as repeating unit a2). [ka]

[0075] In formulas (a1) and (a2), R A Each of Y is independently a hydrogen atom or a methyl group. 1 Y is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. 2 is a single bond or an ester bond. 3 R is a single bond, an ether bond or an ester bond. 11 and R 12 are each independently an acid labile group. When the base polymer contains both the repeating unit a1 and the repeating unit a2, R 11 and R 12 may be the same or different. 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, some of the carbon atoms of which may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4, with the proviso that 1≦a+b≦5.

[0076] Examples of monomers that provide the repeating unit a1 include, but are not limited to, those shown below. A and R 11 is the same as above. [ka]

[0077] Examples of monomers that provide the repeating unit a2 include, but are not limited to, those shown below. A and R 12 is the same as above. [ka]

[0078] In formulas (a1) and (a2), R 11 and R 12 Examples of the acid labile group represented by the formula (I) include those described in JP-A-2013-80033 and JP-A-2013-83821.

[0079] Typically, the acid labile group includes those represented by the following formulae (AL-1) to (AL-3). [ka] (In the formula, the dashed lines represent bonds.)

[0080] In formulas (AL-1) and (AL-2), R L1 and R L2are each independently a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 40 carbon atoms, more preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms.

[0081] In formula (AL-1), c is an integer of 0 to 10, and an integer of 1 to 5 is preferable.

[0082] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain 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. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms. L2 , R L3 and R L4 Any two of these may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0083] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms. L5 , R L6 and R L7 Any two of these may be bonded to each other to form, together with the carbon atom to which they are bonded, a ring having 3 to 20 carbon atoms. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0084] The base polymer may contain a repeating unit b containing a phenolic hydroxy group as an adhesive group. Examples of monomers that provide the repeating unit b include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0085] [ka]

[0086] [ka]

[0087] The base polymer may contain a repeating unit c containing a hydroxy group other than a phenolic hydroxy group, a lactone ring, a sultone ring, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonyl group, a sulfonyl group, a cyano group, or a carboxy group as another adhesive group. 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]

[0088] [ka]

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] [ka]

[0093] [ka]

[0094] [ka]

[0095] [ka]

[0096] The base polymer may include repeat units d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or derivatives thereof. Monomers that provide repeat units d include, but are not limited to, those shown below. [ka]

[0097] The base polymer may include repeat units e derived from styrene, vinyl naphthalene, vinyl anthracene, vinyl pyrene, methylene indane, vinyl pyridine, or vinyl carbazole.

[0098] The base polymer may contain a repeating unit f derived from an onium salt containing a polymerizable unsaturated bond. Preferred repeating units f include a repeating unit represented by the following formula (f1) (hereinafter also referred to as repeating unit f1), a repeating unit represented by the following formula (f2) (hereinafter also referred to as repeating unit f2), and a repeating unit represented by the following formula (f3) (hereinafter also referred to as repeating unit f3). The repeating units f1 to f3 may be used alone or in combination of two or more. [ka]

[0099] In formulas (f1) to (f3), 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. 11 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 2 is a single bond or an ester bond. 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)-. Z 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, an iodine atom, or a bromine atom. 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. 5is 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.

[0100] In formulas (f1) to (f3), 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 4 ~R 6 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. A part 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 a part of -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 anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. 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 explanation of formulas (1) and (2) as R 4 and R 5 and the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0101] In formula (f1), 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.

[0102] Other examples of the non-nucleophilic counter ion include a sulfonate ion represented by the following formula (f1-1) in which the α-position is substituted with a fluorine atom, and a sulfonate ion represented by the following formula (f1-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group. [ka]

[0103] In formula (f1-1), 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.

[0104] In formula (f1-2), R32 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 6 to 20 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 in formula (3A') described later. 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0105] Examples of the cation of the monomer that gives the repeating unit f1 include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0106] Specific examples of the cation of the monomer that gives the repeating unit f2 or f3 include the same as those exemplified as the cation of the sulfonium salt represented by formula (1) or (2).

[0107] Examples of the anion of the monomer that gives the repeating unit f2 include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] [ka]

[0113] [ka]

[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] [ka]

[0118] [ka]

[0119] Examples of the anion of the monomer that gives the repeating unit f3 include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0120] [ka]

[0121] The repeating units f1 to f3 function as an acid generator. By bonding 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 unit f is used, the incorporation of an additive-type acid generator, which will be described later, can be omitted.

[0122] In the base polymer, the contents of the repeating units a1, a2, b, c, d, e, f1, f2 and f3 are preferably 0≦a1≦0.9, 0≦a2≦0.9, 0≦a1+a2≦0.9, 0≦b≦0.9, 0≦c≦0.9, 0≦d≦0.5, 0≦e≦0.5, 0≦f1≦0.5, 0≦f2≦0.5, 0≦f3≦0.5, 0≦f1+f2+f3≦0.5, and more preferably 0≦a1≦0.8, 0≦a2≦0.8, 0≦a1+a2≦0.8, 0≦ ≦b≦0.8, 0≦c≦0.8, 0≦d≦0.4, 0≦e≦0.4, 0≦f1≦0.4, 0≦f2≦0.4, 0≦f3≦0.4, and 0≦f1+f2+f3≦0.4 are more preferable, and 0≦a1≦0.7, 0≦a2≦0.7, 0≦a1+a2≦0.7, 0≦b≦0.7, 0≦c≦0.7, 0≦d≦0.3, 0≦e≦0.3, 0≦f1≦0.3, 0≦f2≦0.3, 0≦f3≦0.3, and 0≦f1+f2+f3≦0.3 are even more preferable, provided that a1+a2+b+c+d+f1+f2+f3+e=1.0.

[0123] To synthesize the base polymer, for example, a monomer that provides the repeating unit described above may be polymerized in an organic solvent by heating with the addition of a radical polymerization initiator.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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. When the Mw is within the above range, the resist film has good heat resistance and solubility in an alkaline developer.

[0129] In addition, when the base polymer has a wide molecular weight distribution (Mw / Mn), low and high molecular weight polymers are present, which may result in foreign matter being found on the pattern after exposure or deterioration of the pattern shape. 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 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.

[0130] The base polymer may include two or more polymers having different composition ratios, Mw, and Mw / Mn.

[0131] [Acid generator] The resist material of the present invention may contain an acid generator (hereinafter also referred to as an additive acid generator) that generates a strong acid. In the case of a chemically amplified positive resist material, the strong acid means a compound having sufficient acidity to cause a deprotection reaction of an acid labile group of a base polymer, and in the case of a chemically amplified negative resist material, it means a compound having sufficient acidity to cause a polarity change reaction or a crosslinking reaction by an acid. By containing such an acid generator, the sulfonium salt A functions as a quencher, and the resist material of the present invention can function as a chemically amplified positive resist material or a chemically amplified negative resist material.

[0132] 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.

[0133] In addition, as the photoacid generator, a sulfonium salt represented by the following formula (3-1) or an iodonium salt represented by the following formula (3-2) can also be suitably used. [ka]

[0134] In formulas (3-1) and (3-2), 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 saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 4 ~R 6 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. Also, R 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 is as defined in the explanation of formulas (1) and (2) as R 4 and R 5 and the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0135] 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) or (2).

[0136] Examples of the cation of the iodonium salt represented by formula (3-2) include, but are not limited to, those shown below. [ka]

[0137] [ka]

[0138] In formulas (3-1) and (3-2), Xa - is an anion selected from the following formulas (3A) to (3D). [ka]

[0139] In formula (3A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0140] The anion represented by formula (3A) is preferably one represented by the following formula (3A'). [ka]

[0141] In formula (3A'), 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.

[0142] 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 methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosanyl groups; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, and norbornyl. groups, 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.

[0143] 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 anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. Examples of hydrocarbyl groups 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.

[0144] Synthesis of sulfonium salts containing an anion represented by formula (3A') 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.

[0145] Examples of the anion represented by formula (3A) include the same anions as those exemplified as the anion represented by formula (1A) in JP 2018-197853 A.

[0146] In formula (3B), R fb1 and R fb2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 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.

[0147] In formula (3C), R fc1 , R fc2 and R fc3are 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. 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.

[0148] In formula (3D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0149] The synthesis of a sulfonium salt containing an anion represented by formula (3D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

[0150] Examples of the anion represented by formula (3D) include the same anions as those exemplified as the anion represented by formula (1D) in JP 2018-197853 A.

[0151] Although the photoacid generator containing the anion represented by formula (3D) does not have a fluorine atom at the α-position of the sulfo group, it has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave the acid labile group in the base polymer, and can therefore be used as a photoacid generator.

[0152] As the photoacid generator, a compound represented by the following formula (4) can also be suitably used. [ka]

[0153] In formula (4), 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 formulas (1) and (2) as R 4 and R 5 and the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0154] R 201 and R 202The 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, an oxanorbornyl group, a tricyclo[5.2.1.0 2,6 cyclic 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 anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0155] 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 anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. As the heteroatom, an oxygen atom is preferable.

[0156] In formula (4), LA is 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.

[0157] In formula (4), X A , X B , X C and X D are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. A , X B , X C and X D At least one of the groups is a fluorine atom or a trifluoromethyl group.

[0158] In formula (4), k is an integer of 0 to 3.

[0159] The photoacid generator represented by formula (4) is preferably one represented by the following formula (4'). [ka]

[0160] In formula (4'), L A 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 hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include 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.

[0161] Examples of the photoacid generator represented by formula (4) include the same as those exemplified as the photoacid generator represented by formula (2) in JP2017-26980A.

[0162] Among the photoacid generators, those containing an anion represented by formula (3A') or (3D) are particularly preferred because of their small acid diffusion and excellent solubility in solvents. Also, those represented by formula (4') are particularly preferred because of their extremely small acid diffusion.

[0163] 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 (5-1) or (5-2). [ka]

[0164] In formulas (5-1) and (5-2), 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.

[0165] In formulas (5-1) and (5-2), 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.

[0166] In formulas (5-1) and (5-2), 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.

[0167] In formulas (5-1) and (5-2), 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.

[0168] In formulas (5-1) and (5-2), 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 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 may be the same or different from each other.

[0169] 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.

[0170] In formulas (5-1) and (5-2), 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.

[0171] In formulas (5-1) and (5-2), 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 4 ~R 6 Examples of the hydrocarbyl group include the same as those exemplified above as the hydrocarbyl group represented by the formula (1). In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone ring, a sulfo group, or a sulfonium salt-containing group, and some of the -CH2- 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 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 as defined in the explanation of formulas (1) and (2) as R 4 and R 5 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.

[0172] Examples of the cation of the sulfonium salt represented by formula (5-1) include the same as those exemplified as the cation of the sulfonium salt represented by formula (1) or (2). 5 Examples of the cation of the iodonium salt represented by formula (-2) include the same as those exemplified as the cation of the iodonium salt represented by formula (3-2).

[0173] Examples of the anion of the onium salt represented by formula (5-1) or (5-2) include, but are not limited to, those shown below. In the following formula, X BI is the same as above. [ka]

[0174] [ka]

[0175]

change

[0176]

change

[0177]

change

[0178]

change

[0179]

change

[0180]

change

[0181]

change

[0182]

change

[0183]

change

[0184]

change

[0185]

change

[0186]

change

[0187]

change

[0188]

change

[0189]

change

[0190]

change

[0191]

change

[0192]

change

[0193]

change

[0194]

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[0195]

change

[0196] When the resist material of the present invention contains an additive acid generator, the content thereof is preferably 0.1 to 50 parts by mass, and more preferably 1 to 40 parts by mass, relative to 100 parts by mass of the base polymer. The resist material of the present invention can function as a chemically amplified resist material by the base polymer containing any of the repeating units f1 to f3 and / or by containing an additive acid generator.

[0197] [Organic solvents] The resist material of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the above-mentioned components and the components described below. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] to

[0145] of JP-A-2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol Examples of the monoethyl ether include ethers such as propylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; and lactones such as γ-butyrolactone.

[0198] In the resist material of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, based on 100 parts by mass of the base polymer. The organic solvent may be used alone or in combination of two or more kinds.

[0199] [Other ingredients] In addition to the components described above, the resist material of the present invention may contain surfactants, dissolution inhibitors, crosslinking agents, quenchers other than sulfonium salt A (hereinafter referred to as other quenchers), water repellency enhancers, acetylene alcohols, etc.

[0200] 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 resist material of the present invention contains the surfactant, the content thereof is preferably 0.0001 to 10 parts by mass relative to 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more kinds.

[0201] When the resist material of the present invention is a positive type, the difference in dissolution rate between the exposed and unexposed areas can be further increased by adding a dissolution inhibitor, 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.

[0202] When the resist material of the present invention is a positive type and contains the dissolution inhibitor, the content thereof is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, based on 100 parts by mass of the base polymer. The dissolution inhibitor may be used alone or in combination of two or more kinds.

[0203] On the other hand, when the resist material of the present invention is a negative type, a crosslinking agent can be added to reduce the dissolution rate of the exposed area to obtain a negative type pattern. Examples of the crosslinking agent include epoxy compounds, melamine compounds, guanamine compounds, glycoluril compounds or urea compounds, isocyanate compounds, azide compounds, and compounds containing double bonds such as alkenyloxy groups, which are substituted with at least one group selected from methylol groups, alkoxymethyl groups, and acyloxymethyl groups. These may be used as additives, or may be introduced as pendant groups into the polymer side chain. Compounds containing hydroxyl groups may also be used as crosslinking agents.

[0204] Examples of the epoxy compound include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0205] Examples of the melamine compound include hexamethylol melamine, hexamethoxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are methoxymethylated or a mixture thereof, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are acyloxymethylated or a mixture thereof, and the like.

[0206] Examples of the guanamine compound include tetramethylol guanamine, tetramethoxymethyl guanamine, a compound in which 1 to 4 methylol groups of tetramethylol guanamine are methoxymethylated or a mixture thereof, tetramethoxyethyl guanamine, tetraacyloxyguanamine, a compound in which 1 to 4 methylol groups of tetramethylol guanamine are acyloxymethylated or a mixture thereof, and the like.

[0207] Examples of the glycoluril compound include tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, a compound in which 1 to 4 methylol groups of tetramethylol glycoluril are methoxymethylated or a mixture thereof, a compound in which 1 to 4 methylol groups of tetramethylol glycoluril are acyloxymethylated or a mixture thereof, etc. Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound in which 1 to 4 methylol groups of tetramethylol urea are methoxymethylated or a mixture thereof, tetramethoxyethyl urea, etc.

[0208] Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0209] Examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0210] Examples of the compound containing an alkenyloxy group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, and trimethylolpropane trivinyl ether.

[0211] When the resist composition of the present invention is a negative type and contains the crosslinking agent, the content thereof is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, based on 100 parts by mass of the base polymer. The crosslinking agent may be used alone or in combination of two or more kinds.

[0212] Examples of the other quenchers include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, or 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, carbamates, and the like. 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 Patent No. 3790649, are preferred. By adding such a basic compound, for example, it is possible to further suppress the diffusion rate of the acid in the resist film or correct the shape.

[0213] Other quenchers include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids not fluorinated at the α-position, as described in JP-A-2008-158339. Sulfonic acids, imide acids, or methide acids fluorinated at the α-position are necessary for deprotecting acid labile groups of carboxylic acid esters, but the sulfonic acids or carboxylic acids not fluorinated at the α-position are released by salt exchange with onium salts not fluorinated at the α-position. Sulfonic acids and carboxylic acids not fluorinated at the α-position do not undergo deprotection reactions, and therefore function as quenchers.

[0214] Other examples of the quencher include the polymer-type quencher described in JP 2008-239918 A. This enhances the rectangularity of the resist pattern by orienting 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.

[0215] When the resist composition of the present invention contains another quencher, the content thereof is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, relative to 100 parts by mass of the base polymer. The other quenchers may be used alone or in combination of two or more kinds.

[0216] 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 resist composition of the present invention contains the water repellency improver, the content thereof is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the base polymer. The water repellency improver may be used alone or in combination of two or more kinds.

[0217] The acetylene alcohols include those described in paragraphs

[0179] to

[0182] of JP 2008-122932 A. When the resist material of the present invention contains the acetylene alcohols, 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.

[0218] [Pattern formation method] When the resist material of the present invention is used for manufacturing various integrated circuits, 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 chemically amplified resist material, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0219] First, the 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 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.

[0220] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, EB, EUV radiation with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. When ultraviolet radiation, far ultraviolet radiation, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. are used as the high-energy radiation, the exposure dose is preferably 1 to 200 mJ / cm2, either directly or using a mask for forming a desired pattern. 2 Approximately, more preferably 10 to 100 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 300 μC / cm 2 Approximately, more preferably 0.5 to 200 μC / cm 2 The resist material of the present invention is suitable for fine patterning using high-energy radiation 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.

[0221] After the exposure, PEB may or may not be performed on a hot plate or in an oven, preferably at 30 to 150° C. for 10 seconds to 30 minutes, more preferably at 50 to 120° C. for 30 seconds to 20 minutes.

[0222] After exposure or PEB, the exposed resist film is developed by a conventional method such as a dip method, a puddle method, or a spray method 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, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, to form a desired pattern. In the case of a positive resist material, the portion irradiated with light dissolves in the developer, and the portion not exposed to light does not dissolve, forming a desired positive pattern on the substrate. In the case of a negative resist material, the opposite is true to the case of a positive resist material, where the portion irradiated with light becomes insoluble in the developer, and the portion not exposed to light dissolves.

[0223] A negative pattern can also be obtained by organic solvent development using a positive resist material containing a base polymer containing an acid labile group. The developer used in this case is 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 may be used alone or in combination of two or more.

[0224] 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.

[0225] Examples of the alcohol having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, Examples of such alcohols include 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol.

[0226] 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.

[0227] Examples of the alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Examples of the alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of the alkynes having 6 to 12 carbon atoms include hexine, heptine, and octyne.

[0228] Examples of the aromatic solvent include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0229] 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.

[0230] 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

[0231] 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.

[0232] The structures of quenchers Q-1 to Q-18 used in the resist material are shown below. [ka]

[0233] [ka]

[0234] [ka]

[0235] [Synthesis Example] Synthesis of base polymers (polymers 1 to 5) Each monomer was combined and copolymerized in THF, which was a solvent, and then crystallized in methanol. After repeated washing with hexane, the product was isolated and dried to obtain the base polymers (polymers 1 to 5) with the compositions shown below. The compositions of the obtained base polymers were as follows: 1 Mw and Mw / Mn were confirmed by H-NMR and GPC (solvent: THF, standard: polystyrene). [ka]

[0236] [ka]

[0237] [Examples 1 to 22, Comparative Examples 1 to 3] Preparation of resist materials and their evaluation (1) Preparation of resist material Resist materials were prepared by filtering a solution in which each component was dissolved according to the composition shown in Table 1 through a 0.2 μm filter. The resist materials of Examples 1 to 21 and Comparative Examples 1 and 2 were positive-type, and the resist materials of Example 22 and Comparative Example 3 were negative-type.

[0238] In Table 1, the components are as follows. Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (Diacetone Alcohol) EL (Ethyl lactate)

[0239] Acid generator: PAG-1~PAG-5 [ka]

[0240] Blend quencher: bQ-1, bQ-2 [ka]

[0241] Comparison quenchers: cQ-1, cQ-2 [ka]

[0242] (2) EUV lithography evaluation Each resist material shown in Table 1 was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a thickness of 20 nm, and the substrate was pre-baked at 100°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. The Si substrate was exposed to i-line at 200 mJ / cm 2 The entire surface was exposed to light at an exposure dose of 100 nm. Next, the resist film was exposed to light using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, a hole pattern mask with a pitch of 44 nm on the wafer and a +20% bias), and PEB was performed on a hot plate at a temperature shown in Table 1 for 60 seconds, and development was performed with a 2.38 mass % TMAH aqueous solution for 30 seconds to obtain hole patterns with a dimension of 22 nm in Examples 1 to 21 and Comparative Examples 1 and 2, and dot patterns with a dimension of 22 nm in Example 22 and Comparative Example 3. Using a Hitachi High-Technologies Corporation length measuring SEM (CG6300), the exposure dose when holes or dots were formed with a dimension of 22 nm was measured and used as the sensitivity, and the dimensions of 50 holes or dots were also measured, and the CDU was calculated by multiplying the standard deviation (σ) by three (3σ). The results are shown in Table 1.

[0243] [Table 1]

[0244] The results shown in Table 1 show that the resist material of the present invention, which contains a sulfonium salt of an aromatic carboxylic acid having a nitrogen-containing cyclic group and a benzene ring substituted with a nitro group, has high sensitivity and improved CDU.

Claims

1. A resist material comprising a quencher containing a sulfonium salt of an aromatic carboxylic acid having a nitrogen atom-containing cyclic group and a benzene ring substituted with a nitro group, and an acid generator.

2. 2. The resist material according to claim 1, wherein the acid generator generates a sulfonic acid, an imide acid or a methide acid.

3. The resist material according to claim 1 or 2, further comprising a base polymer.

4. A resist material comprising: a quencher containing a sulfonium salt of an aromatic carboxylic acid having a nitrogen-containing cyclic group and a benzene ring substituted with a nitro group; and a base polymer containing at least one repeating unit selected from those represented by the following formulas (f1) to (f3): 【Chemistry 1】 (In the formula, each R A is independently a hydrogen atom or a methyl group. Z 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -O-Z 11 -, -C(═O)-O-Z 11 -, or -C(═O)-NH-Z 11 -. Z 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(═O)-O-, -Z 31 -O-, or -Z 31 -O-C(═O)-. Z 31 is 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, an iodine atom, or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group or a carbonyl group. Z 5 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 -. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom or a hydroxy group. R 21 to R 28 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. R 23 and R 24 , or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. M- is a non-nucleophilic counter ion.

5. The resist material according to any one of claims 1 to 4, wherein the sulfonium salt is represented by the following formula (1) or (2): 【Chemistry 1】 (In the formula, m is 1 or 2. n1 is 1 or 2, and n2 is an integer from 0 to 3, provided that 1≦n1+n2≦4. The circle R in the formula is a heterocyclic ring having 3 to 12 carbon atoms and containing a nitrogen atom, and may contain at least one bond selected from an ether bond, an ester bond, a sulfide bond, a sulfonyl group, and -N=; R 1 and a carbon atom contained in the ring may be bonded to form a bridged ring. The circle R' is a heterocycle having 3 to 12 carbon atoms containing a nitrogen atom in the formula, and is an ether bond, an ester bond, a sulfide bond, a sulfonyl group, -N= and -N(R 1 )- may contain at least one selected from the following. L is an ether bond, an ester bond, an amide bond or a thioester bond. X 1 and X 2 are each independently a single bond or a saturated hydrocarbylene group having 1 to 20 carbon atoms, and the saturated hydrocarbylene group may contain at least one bond selected from an ether bond, an ester bond and a sulfide bond. R 1 is a hydrogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms, an acetyl group, a methoxycarbonyl group, an ethoxycarbonyl group, an n-propyloxycarbonyl group, an isopropyloxycarbonyl group, a tert-butoxycarbonyl group, a tert-pentyloxycarbonyl group, a methylcyclopentyloxycarbonyl group, an ethylcyclopentyloxycarbonyl group, a propylcyclopentyloxycarbonyl group, a phenyl group, a benzyl group, a naphthyl group, a naphthylmethyl group, a methylcyclohexyloxycarbonyl group, an ethylcyclohexyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, an allyloxycarbonyl group, a methoxymethyl group, an ethoxymethyl group, a propoxymethyl group, or a butoxymethyl group. R 2 represents a hydrogen atom, a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms, or a phenyl group, and some or all of the hydrogen atoms of the saturated hydrocarbyl group or phenyl group may be substituted with halogen atoms. R 3 is a hydrogen atom, a halogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. R 4 ~R 6 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 4 and R 5 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

6. The resist material according to any one of claims 1 to 5, wherein the base polymer contains a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2): 【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 and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 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 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of the carbon atoms of which may be substituted with ether bonds or ester bonds. a is 1 or 2. b is an integer from 0 to 4, provided that 1≦a+b≦5.

7. The resist material of claim 6 which is a chemically amplified positive resist material.

8. 6. The resist material according to claim 1, wherein the base polymer does not contain an acid labile group.

9. The resist material of claim 8 which is a chemically amplified negative resist material.

10. The resist material according to any one of claims 1 to 9, further comprising an organic solvent.

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

12. The resist material according to claim 3, wherein the base polymer further comprises at least one repeating unit selected from the repeating units represented by the following formulas (f1) to (f3): 【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, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine 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 and or R 26 and R 27 and 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.)

13. A pattern forming method comprising the steps of: forming a resist film on a substrate using the resist material according to any one of claims 1 to 12; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

14. 14. The method for forming a pattern according to claim 13, wherein the high-energy beam is a KrF excimer laser beam, an ArF excimer laser beam, an electron beam or an extreme ultraviolet ray having a wavelength of 3 to 15 nm.

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