Resist material and pattern forming method

Abstract

To provide a resist material which has 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 an acid generator containing a sulfonium salt or iodonium salt of an arylsulfonic acid substituted with an iodine atom.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 5nm and 3nm node devices. Furthermore, studies are underway to use EUV lithography for next-generation 2nm node devices and the generation after that, the 14Å node, and Belgium's IMEC has announced the development of 2Å devices.

[0003] As patterns become finer, problems are being raised about the line width roughness (LWR) of line patterns and the dimensional uniformity (CDU) of hole and dot patterns. The effects of uneven distribution and aggregation of base polymers and acid generators, and the effects of acid diffusion have been pointed out. Furthermore, as resist films become thinner, LWR and CDU tend to increase, and the deterioration of LWR and CDU due to thinning accompanying the progress of finer patterns is becoming a serious problem.

[0004] EUV resist materials must simultaneously achieve high sensitivity, high resolution, and low LWR. Shortening the acid diffusion distance improves LWR and CDU, but at the expense of low sensitivity. For example, lowering the post-exposure bake (PEB) temperature improves LWR and CDU, but at the expense of low sensitivity. Increasing the amount of quencher added also improves LWR and CDU, but at the expense of low sensitivity. It is necessary to break the trade-off between sensitivity and LWR.

[0005] Resist materials have been proposed in which an onium salt containing an anion having an iodine atom is added as an acid generator (Patent Documents 1 to 3). By containing iodine atoms, which have high absorption of EUV, the efficiency of decomposition of the acid generator during exposure is increased, resulting in high sensitivity. The amount of photon absorption is increased, and physical contrast can be improved.

[0006] The health effects of perfluoroalkyl substances (PFAS) have been pointed out, and there are moves to impose restrictions on the manufacture and sale of PFAS compounds under the European REACH. Many compounds containing PFAS are currently used in semiconductor lithography. For example, materials containing PFAS are used in surfactants, acid generators, etc.

[0007] A comparison has been reported between resist materials containing an acid generator that generates an anion having a fluorine atom bonded to the polymer main chain and an acid generator that generates an anion that does not have fluorine bonded to the polymer main chain (Non-Patent Document 1). It is described that a polymer-bound acid generator that generates an anion having a fluorine atom provides higher resolution. Sulfonic acid, which has a high acid strength, provides a higher efficiency of the deprotection reaction, and the introduction of fluorine atoms is effective in increasing the acid strength.

[0008] A resist material has been reported that generates anions with increased acidity by introducing nitro groups or chlorine atoms without using fluorine atoms (Non-Patent Document 2). A resist material containing an acid generator that generates anions substituted with nitro groups or chlorine atoms may have higher rectangularity than a resist material containing an acid generator that generates anions substituted with fluorine atoms, but has the disadvantage of low sensitivity and large MEEF as shown in Table 2 in the literature, which is due to the low dissolution contrast caused by the low acidity of the anions and low deprotection reactivity. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2018-159744 A [Patent Document 2] JP 2018-155908 A [Patent Document 3] JP 2023-21084 A [Non-patent literature]

[0010] [Non-Patent Document 1] SPIE Vol. 6519 6565191F-1 (2007) [Non-Patent Document 2] SPIE Vol. 7639 76390D-1 (2010) Summary of the Invention [Problem to be solved by the invention]

[0011] There is a demand for the development of a resist material that has higher sensitivity than conventional resist materials and is capable of improving the LWR of a line pattern and the CDU of a hole pattern.

[0012] 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]

[0013] Means for Solving the Problems The present inventors have conducted extensive research in order to achieve the above-mentioned object, and as a result have found that by using a sulfonium salt or iodonium salt of an arylsulfonic acid substituted with an iodine atom as an acid generator, it is possible to obtain a resist material which has high sensitivity, improved LWR and CDU, high contrast, excellent resolution, and a wide process margin, and have thus completed the present invention.

[0014] That is, the present invention provides the following resist material and pattern forming method. 1. A resist material containing an acid generator that contains a sulfonium salt or iodonium salt of an arylsulfonic acid substituted with two or more iodine atoms. 2. The resist material of 1, wherein the sulfonium salt or iodonium salt of arylsulfonic acid substituted with an iodine atom comprises an acid generator containing a sulfonium salt or iodonium salt represented by the following formula (1): [ka] (In the formula, p is an integer of 0 to 10, and q is an integer of 2 to 7. R 1 is a hydrogen atom, a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, -N(R 1A )-C(=O)-R 1B , -N(R 1A )-C(=O)-OR 1B Or -N(R 1A )-S(=O)2-R 1B The hydrocarbyl group, the hydrocarbyloxy group, the hydrocarbyloxycarbonyl group, the hydrocarbylcarbonyloxy group and the hydrocarbylsulfonyloxy group may contain at least one selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, an amino group, an ester bond, an ether bond, a urethane bond, a urea bond, a carbonate bond, an amide bond, a sulfonate ester bond, a carbonyl group, a sulfide group and a sulfonyl group. 1A R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and the saturated hydrocarbyl group 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. 1Bis an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 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. Ar is a (p+q+1)-valent aromatic hydrocarbon group having 6 to 16 carbon atoms. M + is a sulfonium cation or an iodonium cation. 3. The resist material of 2, wherein q is 2, 3, 4 or 5. 4. A resist material according to any one of 1 to 3, further comprising a base polymer. 5. The resist material of 4, wherein the base polymer contains a repeating unit represented by the following formula (a1) or (a2): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. X 1 represents a single bond, a phenylene group or naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one bond selected from an ester bond, an ether bond and a lactone ring, and the phenylene group, naphthylene group and linking group may contain at least one bond selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms and a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms. X 2 is a single bond or an ester bond. X 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 represents a saturated hydrocarbyl group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbylcarbonyl group having 2 to 5 carbon atoms, a cyano group, or a saturated hydrocarbyloxycarbonyl group having 2 to 5 carbon atoms. R 14represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain at least one bond selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms, an ether bond, and an ester bond. a is an integer from 0 to 4. 6. The resist material of 5, which is a chemically amplified positive resist material. 7. The resist material of 4, wherein the base polymer does not contain an acid labile group. 8. The resist material of 7, which is a chemically amplified negative resist material. 9. A resist material according to any one of 1 to 8, further comprising an organic solvent. 10. A resist material according to any one of 1 to 9, further comprising a quencher. 11. A resist material according to any one of 1 to 10, further comprising a surfactant. 12. 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 11, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer. 13. The pattern formation method according to 12, wherein the high-energy beam is ArF excimer laser light having a wavelength of 193 nm, KrF excimer laser light having a wavelength of 248 nm, an electron beam (EB), or EUV having a wavelength of 3 to 15 nm. Effect of the Invention

[0015] Sulfonium salts or iodonium salts of arylsulfonic acids substituted with multiple iodine atoms have the characteristics of greater EUV absorption, higher acid strength, and suppression of acid diffusion than unsubstituted arylsulfonic acids and even arylsulfonic acids substituted with fluorine atoms. This makes it possible to prevent a decrease in resolution due to blurring caused by acid diffusion, and the high absorption increases the proportion of direct excitation reactions, suppressing the diffusion of secondary electrons, resulting in low diffusion characteristics and improving LWR and CDU. This makes it possible to construct a resist material that is highly sensitive and has improved LWR and CDU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] [Resist material] The resist material of the present invention contains an acid generator containing a sulfonium salt or iodonium salt of arylsulfonic acid substituted with multiple iodine atoms. The arylsulfonic acid substituted with iodine atoms has a higher acid strength than arylsulfonic acid substituted with fluorine atoms. In addition, the salt has high contrast and small acid diffusion due to the high absorption of iodine atoms, the high effect of improving the acid strength of sulfonic acid, and the bulkiness of arylsulfonic acid. This can improve LWR and CDU.

[0017] The effect of improving LWR and CDU by the acid generator used in the present invention is effective in both positive pattern formation and negative pattern formation by aqueous alkaline solution development, and in negative pattern formation by organic solvent development.

[0018] [Acid generator] The sulfonium salt or iodonium salt of arylsulfonic acid substituted with a plurality of iodine atoms is preferably one represented by the following formula (1). [ka]

[0019] In formula (1), p is an integer of 0 to 10. q is an integer of 2 to 7, with 2, 3, 4 or 5 being preferred.

[0020] In formula (1), R 1 is a hydrogen atom, a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, -N(R 1A )-C(=O)-R 1B, -N(R 1A )-C(=O)-OR 1B Or -N(R 1A )-S(=O)2-R 1B The hydrocarbyl group, the hydrocarbyloxy group, the hydrocarbyloxycarbonyl group, the hydrocarbylcarbonyloxy group and the hydrocarbylsulfonyloxy group may contain at least one selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, an amino group, an ester bond, an ether bond, a urethane bond, a urea bond, a carbonate bond, an amide bond, a sulfonate ester bond, a carbonyl group, a sulfide group and a sulfonyl group. 1A R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and the saturated hydrocarbyl group 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. 1B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 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.

[0021] R 1The hydrocarbyl group represented by the formula (I) and the hydrocarbyl moiety of the hydrocarbyloxy group, the hydrocarbyloxycarbonyl group, the hydrocarbylcarbonyloxy group and the hydrocarbylsulfonyloxy group 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.

[0022] In formula (1), Ar is a (p+q+1)-valent aromatic hydrocarbon group having 6 to 16 carbon atoms. Specific examples of the aromatic hydrocarbon group include groups obtained by eliminating a (p+q+1)-valent hydrogen atom from an aromatic hydrocarbon such as benzene, naphthalene, anthracene, or pyrene.

[0023] Specific examples of the anion of the salt represented by formula (1) include, but are not limited to, those shown below. [ka]

[0024] [ka]

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[0078] In formula (1), M + is a sulfonium cation or an iodonium cation. The sulfonium cation is preferably one represented by the following formula (2), and the iodonium cation is preferably one represented by the following formula (3). [ka]

[0079] In formulas (2) and (3), R 2 ~R 6 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0080] R 2 ~R 6 Specific examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0081] R 2 ~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.

[0082] 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.

[0083] Also, R 2 and R 3 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 lines represent bonds.)

[0084] M + Specific examples of the sulfonium cation represented by the formula (I) include, but are not limited to, those shown below. [ka]

[0085] [ka]

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[0120] M + Specific examples of the iodonium cation represented by the formula (I) include, but are not limited to, those shown below. [ka]

[0121] [ka]

[0122] Examples of methods for synthesizing the sulfonium salt and iodonium salt represented by formula (1) include a method in which an aryl compound substituted with an iodine atom is reacted with fuming sulfuric acid to synthesize an arylsulfonic acid substituted with an iodine atom, which is converted into an ammonium salt or an alkali metal salt by a neutralization reaction with an amine compound, and the ammonium salt is then subjected to salt exchange with a sulfonium salt or an iodonium salt containing a halide anion.

[0123] In the resist material of the present invention, the content of the sulfonium salt or iodonium salt represented by formula (1) is preferably 0.01 to 1,000 parts by mass, and more preferably 0.05 to 500 parts by mass, per 100 parts by mass of the base polymer described below, from the viewpoints of sensitivity and acid diffusion suppression effect.

[0124] [Base polymer] In the case of a positive resist material, the base polymer contained in the resist material of the present invention contains a repeating unit having an acid labile group. The repeating unit having 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]

[0125] In formulas (a1) and (a2), R A are each independently a hydrogen atom or a methyl group. 1X is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one bond selected from an ester bond, an ether bond, and a lactone ring, and the phenylene group, naphthylene group, and linking group may contain at least one bond selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, and a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms. 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 R is each independently an acid labile group. 13 R is a saturated hydrocarbyl group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbylcarbonyl group having 2 to 5 carbon atoms, a cyano group, or a saturated hydrocarbyloxycarbonyl group having 2 to 5 carbon atoms. 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, which may contain at least one bond selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms, an ether bond, and an ester bond. a is an integer of 0 to 4.

[0126] Specific 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]

[0127] [ka]

[0128] Specific 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]

[0129] R 11 or R 12 The acid labile group represented by the formula (AL-1) to (AL-3) below may be selected from various groups. [ka] (In the formula, the dashed lines represent bonds.)

[0130] In formula (AL-1), b is an integer of 0 to 6. L1 is a tertiary hydrocarbyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, a trihydrocarbylsilyl group in which each hydrocarbyl group is a saturated hydrocarbyl group having 1 to 6 carbon atoms, a carbonyl group, a saturated hydrocarbyl group having 4 to 20 carbon atoms containing an ether bond or an ester bond, or a group represented by formula (AL-3). The tertiary hydrocarbyl group means a group obtained by eliminating a hydrogen atom from a tertiary carbon atom of a hydrocarbon.

[0131] R L1The tertiary hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, branched or cyclic. Specific examples thereof include tert-butyl group, tert-pentyl group, 1,1-diethylpropyl group, 1-ethylcyclopentyl group, 1-butylcyclopentyl group, 1-ethylcyclohexyl group, 1-butylcyclohexyl group, 1-ethyl-2-cyclopentenyl group, 1-ethyl-2-cyclohexenyl group, and 2-methyl-2-adamantyl group. Examples of the trihydrocarbylsilyl group include trimethylsilyl group, triethylsilyl group, and dimethyl-tert-butylsilyl group. The saturated hydrocarbyl group containing a carbonyl group, an ether bond or an ester bond may be linear, branched or cyclic, but is preferably cyclic. Specific examples thereof include a 3-oxocyclohexyl group, a 4-methyl-2-oxooxan-4-yl group, a 5-methyl-2-oxooxolan-5-yl group, a 2-tetrahydropyranyl group and a 2-tetrahydrofuranyl group.

[0132] Examples of the acid labile group represented by formula (AL-1) include a tert-butoxycarbonyl group, a tert-butoxycarbonylmethyl group, a tert-pentyloxycarbonyl group, a tert-pentyloxycarbonylmethyl group, a 1,1-diethylpropyloxycarbonyl group, a 1,1-diethylpropyloxycarbonylmethyl group, a 1-ethylcyclopentyloxycarbonyl group, a 1-ethylcyclopentyloxycarbonylmethyl group, a 1-ethyl-2-cyclopentenyloxycarbonyl group, a 1-ethyl-2-cyclopentenyloxycarbonylmethyl group, a 1-ethoxyethoxycarbonylmethyl group, a 2-tetrahydropyranyloxycarbonylmethyl group, and a 2-tetrahydrofuranyloxycarbonylmethyl group.

[0133] Further, examples of the acid labile group represented by formula (AL-1) include groups represented by the following formulae (AL-1)-1 to (AL-1)-10. [ka] (In the formula, the dashed lines represent bonds.)

[0134] In formulae (AL-1)-1 to (AL-1)-10, b is the same as defined above. L8 R is each independently a saturated hydrocarbyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. L9 R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. L10 is a saturated hydrocarbyl group having 2 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic.

[0135] In formula (AL-2), R L2 and R L3 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10. The saturated hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, and an n-octyl group.

[0136] In formula (AL-2), R L4 is a hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10, which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples of the hydrocarbyl group include saturated hydrocarbyl groups having 1 to 18 carbon atoms, and some of the hydrogen atoms may be substituted with a hydroxy group, an alkoxy group, an oxo group, an amino group, an alkylamino group, or the like. Examples of such substituted saturated hydrocarbyl groups include those shown below. [ka] (In the formula, the dashed lines represent bonds.)

[0137] R L2 and R L3 And, R L2 and R L4 and, or RL3 and R L4 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, or together with the carbon atom and the oxygen atom, in which case, R L2 and R L3 , R L2 and R L4 , or R L3 and R L4 are each independently an alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10. The number of carbon atoms in the ring obtained by bonding these is preferably 3 to 10, more preferably 4 to 10.

[0138] Among the acid labile groups represented by formula (AL-2), linear or branched ones include, but are not limited to, those represented by the following formulae (AL-2)-1 to (AL-2)-69, in which the dashed lines represent bonds. [ka]

[0139] [ka]

[0140] [ka]

[0141] [ka]

[0142] Among the acid labile groups represented by formula (AL-2), examples of cyclic groups include a tetrahydrofuran-2-yl group, a 2-methyltetrahydrofuran-2-yl group, a tetrahydropyran-2-yl group, and a 2-methyltetrahydropyran-2-yl group.

[0143] Examples of the acid labile group include groups represented by the following formula (AL-2a) or (AL-2b): The base polymer may be inter- or intra-molecularly crosslinked by the acid labile group. [ka] (In the formula, the dashed lines represent bonds.)

[0144] In formula (AL-2a) or (AL-2b), R L11 and R L12 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 8 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. L11 and R L12 may be bonded to each other to form a ring together with the carbon atom to which they are attached, in which case R L11 and R L12 R is each independently an alkanediyl group having 1 to 8 carbon atoms. L13 are each independently a saturated hydrocarbylene group having 1 to 10 carbon atoms. The saturated hydrocarbylene group may be linear, branched, or cyclic. c and d are each independently an integer of 0 to 10, preferably an integer of 0 to 5, and e is an integer of 1 to 7, preferably an integer of 1 to 3.

[0145] In formula (AL-2a) or (AL-2b), L A is an (e+1)-valent aliphatic saturated hydrocarbon group having 1 to 50 carbon atoms, an (e+1)-valent alicyclic saturated hydrocarbon group having 3 to 50 carbon atoms, an (e+1)-valent aromatic hydrocarbon group having 6 to 50 carbon atoms, or an (e+1)-valent heterocyclic group having 3 to 50 carbon atoms. In addition, a portion of -CH2- in these groups may be substituted with a group containing a hetero atom, and a portion of the hydrogen atoms in these groups may be substituted with a hydroxy group, a carboxy group, an acyl group, or a fluorine atom. A L is preferably a saturated hydrocarbon group having 1 to 20 carbon atoms, such as a saturated hydrocarbylene group, a trivalent saturated hydrocarbon group, or a tetravalent saturated hydrocarbon group, or an arylene group having 6 to 30 carbon atoms. The saturated hydrocarbon group may be linear, branched, or cyclic. Bis -C(=O)-O-, -NH-C(=O)-O- or -NH-C(=O)-NH-.

[0146] Examples of the crosslinked acetal group represented by formula (AL-2a) or (AL-2b) include groups represented by the following formulae (AL-2)-70 to (AL-2)-77. [ka] (In the formula, the dashed lines represent bonds.)

[0147] In formula (AL-3), R L5 R is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a fluorine atom. L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cyclic unsaturated hydrocarbyl group having 3 to 20 carbon atoms, and an aryl group having 6 to 10 carbon atoms. In addition, R L5 and R L6 And, R L5 and R L7 and, or R L6 and R L7 may be bonded to each other to form an alicyclic ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.

[0148] Examples of the group represented by formula (AL-3) include a tert-butyl group, a 1,1-diethylpropyl group, a 1-ethylnorbornyl group, a 1-methylcyclopentyl group, a 1-ethylcyclopentyl group, a 1-isopropylcyclopentyl group, a 1-methylcyclohexyl group, a 2-(2-methyl)adamantyl group, a 2-(2-ethyl)adamantyl group, and a tert-pentyl group.

[0149] Further, examples of the group represented by formula (AL-3) include groups represented by the following formulae (AL-3)-1 to (AL-3)-22. [ka] (In the formula, the dashed lines represent bonds.)

[0150] In formulas (AL-3)-1 to (AL-3)-19, R L14 R are each independently a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 20 carbon atoms. L15 and R L17 R are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms. L16 R is an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. The aryl group is preferably a phenyl group. L18 R is a fluorine atom, an iodine atom, a nitro group, or a trifluoromethyl group. L19 are each independently a hydrogen atom, a fluorine atom, an iodine atom, a nitro group, a saturated hydrocarbyl group having 1 to 8 carbon atoms, or a hydrocarbyloxy group having 1 to 8 carbon atoms. f is an integer of 1 to 5.

[0151] Further examples of the acid labile group include groups represented by the following formula (AL-3)-23 or (AL-3)-24: The acid labile group may intramolecularly or intermolecularly crosslink the polymer. [ka] (In the formula, the dashed lines represent bonds.)

[0152] In formulas (AL-3)-23 and (AL-3)-24, R L14 is the same as above. L20is a (g+1)-valent saturated or unsaturated hydrocarbylene group having 1 to 20 carbon atoms or a (g+1)-valent arylene group having 6 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. The saturated or unsaturated hydrocarbylene group may be linear, branched, or cyclic. g is an integer of 1 to 3.

[0153] In addition to these acid labile groups, aromatic group-containing acid labile groups described in Japanese Patent Nos. 5,565,293, 5,434,983, 5,407,941, 5,655,756 and 5,655,755 can also be used.

[0154] The base polymer may contain a repeating unit b containing a phenolic hydroxy group as an adhesive group. Specific 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]

[0155] 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. Specific 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]

[0156] [ka]

[0157] [ka]

[0158] [ka]

[0159] [ka]

[0160] [ka]

[0161] [ka]

[0162] [ka]

[0163] The base polymer may include a repeat unit d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or a derivative thereof. Specific examples of monomers that provide the repeat unit d include, but are not limited to, the following: [ka]

[0164] The base polymer may include repeat units e derived from styrene, vinyl naphthalene, vinyl anthracene, vinyl pyrene, methylene indane, vinyl pyridine, or vinyl carbazole.

[0165] The base polymer may contain a repeating unit f derived from an onium salt containing a polymerizable unsaturated bond. Specific examples of 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]

[0166] 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 hydroxy group, or a halogen atom.

[0167] In formulas (f1) to (f3), 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. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 2 ~R 6 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a 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. In addition, R 23 and R 24 or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, specific examples of the ring include R 2 and R 3may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, similar to those exemplified above.

[0168] In formula (f1), M - is a non-nucleophilic counter ion. Specific examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion, fluoroalkylsulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion and nonafluorobutanesulfonate ion, arylsulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion and 1,2,3,4,5-pentafluorobenzenesulfonate ion, alkylsulfonate ions such as mesylate ion and butanesulfonate ion, imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion and bis(perfluorobutylsulfonyl)imide ion, and methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0169] Further specific 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]

[0170] 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 at least one bond selected from an ether bond, an ester bond, a carbonyl group, a lactone ring, and a fluorine atom.

[0171] In formula (f1-2), R 32represents a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and may contain at least one bond selected from an ether bond, an ester bond, a carbonyl group, and a lactone ring.

[0172] R 31 or R 32 The hydrocarbyl group represented by the formula (I) and the hydrocarbyl portion of the hydrocarbyl carbonyl group may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosyl; cyclic saturated hydrocarbyl groups such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecanyl, tetracyclododecanylmethyl, and dicyclohexylmethyl; alkenyl groups such as allyl; cyclic unsaturated hydrocarbyl groups such as 3-cyclohexenyl; aryl groups such as phenyl, 1-naphthyl, and 2-naphthyl; and aralkyl groups such as benzyl and diphenylmethyl.

[0173] In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the group containing a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. Specific examples of hydrocarbyl groups containing heteroatoms include a tetrahydrofuryl group, a methoxymethyl group, an ethoxymethyl group, a methylthiomethyl group, an acetamidomethyl group, a trifluoroethyl group, a (2-methoxyethoxy)methyl group, an acetoxymethyl group, a 2-carboxy-1-cyclohexyl group, a 2-oxopropyl group, a 4-oxo-1-adamantyl group, and a 3-oxocyclohexyl group.

[0174] Specific examples of the cation of the monomer that gives the repeating unit f1 include, but are not limited to, those shown below. A is the same as above. [ka]

[0175] Specific examples of the cation of the monomer that gives the repeating unit f2 or f3 include, in the explanation of formula (1), M + Examples of the sulfonium cation represented by the formula (I) include the same as those exemplified above.

[0176] Specific examples of monomers that provide the repeating unit f2 include, but are not limited to, those shown below. A is the same as above. [ka]

[0177] [ka]

[0178]

change

[0179]

change

[0180]

change

[0181]

change

[0182]

change

[0183]

change

[0184]

change

[0185]

change

[0186]

change

[0187]

change

[0188] [Chemistry]

[0189] [Chemistry]

[0190] Specific examples of the monomer that gives the repeating unit f3 include, but are not limited to, those shown below. In the following formulas, R A is the same as described above. [Chemistry]

[0191] The repeating units f1 to f3 function as an acid generator. By bonding the acid generator to the polymer main chain, acid diffusion can be reduced, and a decrease in resolution due to blurring of acid diffusion can be prevented. In addition, the LWR and CDU are improved by the uniform dispersion of the acid generator.

[0192] The base polymer for the positive resist material essentially requires the repeating unit a1 or a2 containing an acid-labile group. In this case, the content ratios of the repeating units a1, a2, b, c, d, e, and f are preferably 0 ≦ a1 < 1.0, 0 ≦ a2 < 1.0, 0 < a1 + a2 < 1.0, 0 ≦ b ≦ 0.9, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, and 0 ≦ f ≦ 0.5, more preferably 0 ≦ a1 ≦ 0.9, 0 ≦ a2 ≦ 0.9, 0.1 ≦ a1 + a2 ≦ 0.9, 0 ≦ b ≦ 0.8, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7, and 0 ≦ f ≦ 0.4, and still more preferably 0 ≦ a1 ≦ 0.8, 0 ≦ a2 ≦ 0.8, 0.1 ≦ a1 + a2 ≦ 0.8, 0 ≦ b ≦ 0.75, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Also, a1 + a2 + b + c + d + e + f = 1.0.

[0193] On the one hand, for the base polymer for a negative resist material, an acid-labile group is not necessarily required. Examples of such base polymers include those containing repeating unit b and, optionally, further containing repeating units c, d, e, and / or f. The content ratios of these repeating units are preferably 0 < b ≤ 1.0, 0 ≤ c ≤ 0.9, 0 ≤ d ≤ 0.8, 0 ≤ e ≤ 0.8, and 0 ≤ f ≤ 0.5, more preferably 0.2 ≤ b ≤ 1.0, 0 ≤ c ≤ 0.8, 0 ≤ d ≤ 0.7, 0 ≤ e ≤ 0.7, and 0 ≤ f ≤ 0.4, and still more preferably 0.3 ≤ b ≤ 1.0, 0 ≤ c ≤ 0.75, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.6, and 0 ≤ f ≤ 0.3. When repeating unit f is at least one selected from repeating units f1 to f3, f = f1 + f2 + f3. Also, b + c + d + e + f = 1.0.

[0194] To synthesize the base polymer, for example, monomers that provide the aforementioned repeating units may be heated in an organic solvent with the addition of a radical polymerization initiator to perform polymerization.

[0195] Specific examples of the organic solvent used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, etc. Specific examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, etc. The temperature during polymerization is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0196] When copolymerizing a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid such as an ethoxyethoxy group before polymerization and then deprotected with a weak acid and water after polymerization, or it may be substituted with an acetyl group, a formyl group, a pivaloyl group, etc. and then subjected to alkaline hydrolysis after polymerization.

[0197] 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.

[0198] 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.

[0199] 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 1000 to 500000, more preferably 2000 to 30000. When the Mw is within the above range, the resist film has good heat resistance and solubility in an alkaline developer.

[0200] Furthermore, 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.

[0201] The base polymer may include two or more polymers having different composition ratios, Mw, and Mw / Mn.

[0202] [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. Specific 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 monomethyl ether. Examples of the monomer units 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.

[0203] 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.

[0204] [Quencher] The resist material of the present invention may contain a quencher. The quencher refers to a compound that can trap the acid generated by the acid generator in the resist material, thereby preventing the acid from diffusing into unexposed areas.

[0205] The quencher may be a conventional basic compound. Specific examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

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

[0206] Further, the quencher may be an onium salt such as a sulfonium salt, an iodonium salt, or an ammonium salt of a sulfonic acid, a carboxylic acid, or a fluorinated alkoxide not fluorinated at the α-position, as described in JP-A-2008-158339. A sulfonic acid, an imide acid, or a methide acid having a fluorinated α-position is necessary for deprotecting an acid labile group of a carboxylate ester, but a sulfonic acid, a carboxylic acid, or a fluorinated alcohol not fluorinated at the α-position is released by salt exchange with the onium salt. A sulfonic acid, a carboxylic acid, and a fluorinated alcohol not fluorinated at the α-position do not cause a deprotection reaction, and therefore function as a quencher.

[0207] Specific examples of such quenchers include a compound represented by the following formula (4) (onium salt of sulfonic acid not fluorinated at the α-position), a compound represented by the following formula (5) (onium salt of carboxylic acid), and a compound represented by the following formula (6) (onium salt of alkoxide). [ka]

[0208] In formula (4), R 101 represents a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group.

[0209] R 101 The hydrocarbyl group having 1 to 40 carbon atoms and represented by the formula (I) may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group or an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, a tricyclo[5.2.1.0 2,6 ]Cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as a decyl group, an adamantyl group, and an adamantylmethyl group; alkenyl groups having 2 to 40 carbon atoms, such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 40 carbon atoms, such as a cyclohexenyl group; a phenyl group, a naphthyl group, an alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 5-butylphenyl group, 6-butylphenyl group, 7-butylphenyl group, 8-butylphenyl group, 9-butylphenyl group, 10-butylphenyl group, 11-butylphenyl group, 12-butylphenyl group, 13-butylphenyl group, 14-butylphenyl group, 15-butylphenyl group, 16-butylphenyl group, 17-butylphenyl group, 18-butylphenyl group, 19-butylphenyl group, 20-butylphenyl group, 21-butylphenyl group, 22-butylphenyl group, 23-butylphenyl group, 24-butylphenyl group, 25-butylphenyl group, 26-butylphenyl group, 27-butylphenyl group, 28-butylphenyl group, 29-butylphenyl group, 30-butylphenyl group, 31-butylphenyl group, 32-butylphenyl group, 33-butylphenyl group, 34-butylphenyl group, 35-butylphenyl group, 36-butylphenyl group, 37-butylphenyl group, 38-butylphenyl group, 39-butylphenyl group, 40-butylphenyl group, 41-butylphenyl group, 42-butylphenyl group, 43-butylphenyl group, 44-butylphenyl group, 45-butylphenyl group, 46-butylphenyl group, 4 Examples of such aryl groups include aryl groups having 6 to 40 carbon atoms, such as arylphenyl groups (e.g., 4-n-butylphenyl group, 4-n-butylphenyl group), di- or trialkylphenyl groups (e.g., 2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group), alkylnaphthyl groups (e.g., methylnaphthyl group, ethylnaphthyl group), dialkylnaphthyl groups (e.g., dimethylnaphthyl group, diethylnaphthyl group), and aralkyl groups having 7 to 40 carbon atoms, such as benzyl group, 1-phenylethyl group, and 2-phenylethyl group.

[0210] 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 cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Specific examples of hydrocarbyl groups containing heteroatoms include heteroaryl groups such as thienyl groups; alkoxyphenyl groups such as 4-hydroxyphenyl groups, 4-methoxyphenyl groups, 3-methoxyphenyl groups, 2-methoxyphenyl groups, 4-ethoxyphenyl groups, 4-tert-butoxyphenyl groups, and 3-tert-butoxyphenyl groups; alkoxynaphthyl groups such as methoxynaphthyl groups, ethoxynaphthyl groups, n-propoxynaphthyl groups, and n-butoxynaphthyl groups; dialkoxynaphthyl groups such as dimethoxynaphthyl groups and diethoxynaphthyl groups; and aryloxoalkyl groups such as 2-aryl-2-oxoethyl groups, 2-(1-naphthyl)-2-oxoethyl groups, and 2-(2-naphthyl)-2-oxoethyl groups.

[0211] In formula (5), R 102 R is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. 102 Specific examples of the hydrocarbyl group represented by the formula: 101 Examples of the hydrocarbyl group include the same as those exemplified above. Other specific examples include fluorinated alkyl groups such as a trifluoromethyl group, a trifluoroethyl group, a 2,2,2-trifluoro-1-methyl-1-hydroxyethyl group, and a 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl group; and fluorinated aryl groups such as a pentafluorophenyl group and a 4-trifluoromethylphenyl group.

[0212] In formula (6), R 103represents a saturated hydrocarbyl group having 1 to 8 carbon atoms and at least three fluorine atoms, or an aryl group having 6 to 10 carbon atoms and at least three fluorine atoms, which may contain a nitro group.

[0213] In formulas (4), (5) and (6), Mq + is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation or an ammonium cation, and more preferably a sulfonium cation. Specific examples of the sulfonium cation include those shown in the description of formula (1) below: + Examples of the sulfonium cation represented by the formula (I) include the same as those exemplified above.

[0214] As the quencher, a sulfonium salt of an iodized benzene ring-containing carboxylic acid represented by the following formula (7) can also be suitably used. [ka]

[0215] In formula (7), x is an integer of 1 to 5. y is an integer of 0 to 3. z is an integer of 1 to 3.

[0216] In formula (7), R 111 represents a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which some or all of the hydrogen atoms may be substituted with halogen atoms, or -N(R 111A )-C(=O)-R 111B Or -N(R 111A )-C(=O)-OR 111B R 111A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 111Bis a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms. When y and / or z is 2 or more, each R 111 may be the same or different from each other.

[0217] In formula (7), L 1 is a single bond or a (z+1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, and a carboxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic.

[0218] In formula (7), R 112 , R 113 and R 114 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 2 ~R 6 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0219] Specific examples of the compound represented by formula (7) include those described in JP-A-2017-219836 and JP-A-2021-91666.

[0220] Another example of the quencher is the polymer-type quencher described in JP 2008-239918 A. This quencher enhances the rectangularity of the resist pattern by being oriented on the surface of the resist film. The polymer-type quencher also has the effect of preventing film loss of the pattern and rounding of the pattern top when a protective film for immersion exposure is applied.

[0221] Furthermore, betaine-type sulfonium salts described in Japanese Patent No. 6848776 and Japanese Patent Application Publication No. 2020-37544, fluorine-free methide acids described in Japanese Patent Application Publication No. 2020-55797, sulfonium salts of sulfonamides described in Japanese Patent Application Publication No. 5807552, sulfonium salts of sulfonamides containing iodine atoms described in Japanese Patent Application Publication No. 2019-211751, and acid generators that generate phenols, halogens, and carbonic acid can also be used as quenchers.

[0222] When the resist composition of the present invention contains the 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 quencher may be used alone or in combination of two or more kinds.

[0223] [Other ingredients] In addition to the above-mentioned components, the composition may contain acid generators other than the salt represented by formula (1) (hereinafter referred to as other acid generators), surfactants, dissolution inhibitors, crosslinking agents, water repellency enhancers, acetylene alcohols, etc.

[0224] The other acid generators include compounds (photoacid generators) that generate acid in response to actinic rays or radiation. The photoacid generator may be any compound that generates acid upon exposure to high-energy rays, but is preferably an acid generator that generates sulfonic acid, imide acid, or methide acid. Specific examples of suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate acid generators. Specific examples of the acid generators include those described in paragraphs

[0122] to

[0142] of JP-A-2008-111103, JP-A-2018-5224, and JP-A-2018-25789. When the resist material of the present invention contains another acid generator, the content thereof is preferably 0 to 200 parts by mass, and more preferably 0.1 to 100 parts by mass, relative to 100 parts by mass of the base polymer.

[0225] Specific 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 a surfactant, the content thereof is preferably 0.0001 to 10 parts by mass per 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more kinds.

[0226] In the case where 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. Specific examples of the dissolution inhibitor include a compound having a molecular weight of preferably 100 to 1000, 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.

[0227] 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.

[0228] 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. Specific 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.

[0229] Specific examples of the epoxy compound include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0230] Specific examples of the melamine compound include hexamethylolmelamine, hexamethoxymethylmelamine, a compound in which 1 to 6 methylol groups of hexamethylolmelamine are methoxymethylated or a mixture thereof, hexamethoxyethylmelamine, hexaacyloxymethylmelamine, a compound in which 1 to 6 methylol groups of hexamethylolmelamine are acyloxymethylated or a mixture thereof, and the like.

[0231] Specific examples of the guanamine compound include tetramethylolguanamine, tetramethoxymethylguanamine, a compound in which 1 to 4 methylol groups of tetramethylolguanamine are methoxymethylated or a mixture thereof, tetramethoxyethylguanamine, tetraacyloxyguanamine, a compound in which 1 to 4 methylol groups of tetramethylolguanamine are acyloxymethylated or a mixture thereof, and the like.

[0232] Specific 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. Specific 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.

[0233] Specific examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0234] Specific examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0235] Specific 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.

[0236] 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.

[0237] 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 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.

[0238] Specific examples of 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.

[0239] [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, as a pattern forming method, there can be mentioned a method including the steps of forming a resist film on a substrate using the above-mentioned resist material, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0240] 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.

[0241] Next, the resist film is exposed to high-energy radiation. Specific 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 2The 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.

[0242] 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.

[0243] 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.

[0244] 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. Specific examples of the developer used in this case include 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, and 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.

[0245] 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.

[0246] Specific 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, and 3-hexanol. Examples of such an alcohol 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.

[0247] Specific 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.

[0248] Specific 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, cyclononane, etc. Specific examples of the alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Specific examples of the alkynes having 6 to 12 carbon atoms include hexine, heptine, octyne, etc.

[0249] Specific examples of the aromatic solvent include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0250] 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.

[0251] 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

[0252] 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.

[0253] The structures of the sulfonium salt or iodonium salt acid generators PAG-1 to PAG-21 used in the resist material are shown below. [ka]

[0254] [ka]

[0255] [ka]

[0256] [ka]

[0257] [Synthesis Example] Synthesis of base polymers (polymers P-1 to P-4) Each monomer was combined and copolymerized in THF, a solvent, and then added to methanol. The precipitated solid was washed with hexane, isolated, and dried to obtain base polymers (polymers P-1 to P-4) with the following compositions. The resulting base polymers had the following compositions: 1 Mw and Mw / Mn were confirmed by H-NMR and GPC (solvent: THF, standard: polystyrene). [ka]

[0258] [Examples 1 to 24, Comparative Examples 1 to 4] Preparation of resist materials and their evaluation (1) Preparation of resist material A resist material was 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.

[0259] In Table 1, the components are as follows. Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) EL (Ethyl lactate) DAA (Diacetone Alcohol) PGME (Propylene glycol monomethyl ether)

[0260] Comparative acid generators: cPAG-1~cPAG-3 [ka]

[0261] Quencher: Q-1, Q-2 [ka]

[0262] (2) EUV lithography evaluation Each resist material shown in Table 1 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a thickness of 20 nm, and the substrate was pre-baked at 105°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. The resist film was exposed to light using an EUV scanner NXE3400 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, a hole pattern mask with a pitch of 40 nm on the wafer and a +20% bias), and PEB was performed on a hot plate at the temperature shown in Table 1 for 60 seconds, and development was performed with a 2.38% by mass TMAH aqueous solution for 30 seconds to form hole patterns with a size of 20 nm in Examples 1 to 22 and Comparative Examples 1 to 3, and dot patterns with a size of 20 nm in Example 23 and Comparative Example 4. Using a Hitachi High-Technologies Corporation length measuring SEM (CG6300), the exposure dose when holes or dots were formed with a dimension of 20 nm was measured and taken as the sensitivity, and the dimensions of 50 holes or dots at this time were measured, and the standard deviation (σ) calculated from the results was tripled (3σ) to take the CDU. The results are shown in Table 1.

[0263] [Table 1]

[0264] The results shown in Table 1 indicate that the resist material of the present invention, which contains a sulfonium salt or iodonium salt of an arylsulfonic acid substituted with multiple iodine atoms as an acid generator, has high sensitivity and good CDU.

Claims

1. A resist material comprising an acid generator containing a sulfonium salt or iodonium salt of an arylsulfonic acid substituted with two or more iodine atoms.

2. 2. The resist material according to claim 1, wherein the sulfonium salt or iodonium salt of an arylsulfonic acid substituted with an iodine atom comprises an acid generator containing a sulfonium salt or iodonium salt represented by the following formula (1): 【Chemistry 1】 (In the formula, p is an integer from 0 to 10, and q is an integer from 2 to 7. R 1 represents a hydrogen atom, a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, -N(R 1A )-C(=O)-R 1B , -N(R 1A )-C(=O)-O-R 1B Or -N(R 1A )-S(=O) 2 -R 1B The hydrocarbyl group, the hydrocarbyloxy group, the hydrocarbyloxycarbonyl group, the hydrocarbylcarbonyloxy group and the hydrocarbylsulfonyloxy group may contain at least one selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, an amino group, an ester bond, an ether bond, a urethane bond, a urea bond, a carbonate bond, an amide bond, a sulfonate ester bond, a carbonyl group, a sulfide group and a sulfonyl group. 1A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and the saturated hydrocarbyl group 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. 1B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, which 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. Ar is a (p+q+1)-valent aromatic hydrocarbon group having 6 to 16 carbon atoms. M + is a sulfonium cation or an iodonium cation.

3. The resist material according to claim 2, wherein q is 2, 3, 4 or 5.

4. The resist material according to claim 1 , further comprising a base polymer.

5. The resist material according to claim 4 , wherein the base polymer comprises a repeating unit represented by the following formula (a1) or (a2): 【Chemistry 2】 (In the formula, R A are each independently a hydrogen atom or a methyl group. X 1 represents a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one bond selected from an ester bond, an ether bond, and a lactone ring, and the phenylene group, naphthylene group, and linking group may contain at least one bond selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, and a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms. X 2 is a single bond or an ester bond. X 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 represents a saturated hydrocarbyl group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbylcarbonyl group having 2 to 5 carbon atoms, a cyano group, or a saturated hydrocarbyloxycarbonyl group having 2 to 5 carbon atoms. R 14 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain at least one bond selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms, an ether bond, and an ester bond. a is an integer from 0 to 4.

6. 6. The resist material of claim 5 which is a chemically amplified positive resist material.

7. 5. The resist material of claim 4, wherein the base polymer does not contain an acid labile group.

8. The resist material of claim 7 which is a chemically amplified negative resist material.

9. The resist material according to claim 1, further comprising an organic solvent.

10. The resist material according to claim 1, further comprising a quencher.

11. The resist material according to claim 1, further comprising a surfactant.

12. 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 11; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

13. 13. The pattern forming method according to claim 12, wherein the high-energy radiation is an ArF excimer laser beam having a wavelength of 193 nm, a KrF excimer laser beam having a wavelength of 248 nm, an electron beam, or an extreme ultraviolet ray having a wavelength of 3 to 15 nm.

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