Resist material and pattern forming process

Abstract

To provide a resist material that offers high sensitivity and improved LWR and CDU, regardless of whether it is of positive or negative tone, and a pattern forming method using the resist material.SOLUTION: The present invention provides a resist material comprising an acid generator that includes an onium salt of a sulfonic acid having a linkage of two iodinated or brominated aromatic groups.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 and the next-next generation 2 nm node devices, and Belgium's IMEC has announced the development of 1 nm and 0.7 nm devices.

[0003] As miniaturization progresses, image blurring due to acid diffusion has become a problem. In order to ensure resolution in fine patterns with processing dimensions of 45 nm or less, it has been proposed that control of acid diffusion is important in addition to improving the dissolution contrast, as has been proposed in the past (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] 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 onium salts having anions containing iodine or bromine atoms are added as acid generators (Patent Documents 1 to 5). By containing iodine atoms, which have high absorption of EUV light, and bromine atoms, which have high ionization efficiency, 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] A mechanism for the generation of acid in high-energy rays such as electron beams (EB) and EUV light has been proposed (Non-Patent Document 2). According to this, in EB or EUV exposure, the polymer is ionized, secondary electrons are generated and diffused, and these transfer energy to the acid generator to generate acid. Based on the resist pattern transfer results and simulations, the distance from the light absorption point to the point where acid is generated is estimated to be 2.4 nm (Non-Patent Document 3). This distance includes the diffusion distance of secondary electrons. In this document, the total of the acid diffusion distance and the diffusion distance from the light absorption point to the point where acid is generated is described as 4 to 8 nm when the PEB temperature is changed, so when acid diffusion is suppressed by applying low-temperature PEB or anion-bound PAG polymer, half of the diffusion distance is occupied by the diffusion from the light absorption point to the point where acid is generated. In other words, it can be said that it is important to control not only acid diffusion but also diffusion from the light absorption point to the point where acid is generated, that is, the diffusion of secondary electrons, in miniaturization. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2018-159744 A [Patent Document 2] JP 2018-5224 A [Patent Document 3] JP 2018-25789 A [Patent Document 4] JP 2019-3175 A [Patent Document 5] JP 2023-123183 A [Non-patent literature]

[0008] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) [Non-Patent Document 2] SPIE Vol. 5753 361 (2005) [Non-Patent Document 3] SPIE Vol. 7969 796904-1 (2011) Summary of the Invention [Problem to be solved by the invention]

[0009] 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.

[0010] 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]

[0011] As a result of intensive research into achieving the above object, the present inventors have found that by using a sulfonium salt or iodonium salt containing a sulfonate anion in which two aromatic groups containing iodine or bromine are linearly linked as an acid generator, the acid generator is directly excited by exposure to radiation, and the influence of diffusion of secondary electrons is eliminated, and thus a resist material with high sensitivity, improved LWR and CDU, high contrast, excellent resolution, and a wide process margin can be obtained, thereby completing the present invention.

[0012] That is, the present invention provides the following resist material and pattern forming method. 1. A resist material comprising an acid generator containing an onium salt of a sulfonic acid in which two aromatic groups each having an iodine atom or a bromine atom are linked. 2. The resist material according to 1, wherein the onium salt is represented by the following formula (1): [ka] (In the formula, m is an integer of 1 to 5, n is an integer of 0 to 4, provided that 1≦m+n≦5; p is an integer of 1 to 4, q is an integer of 0 to 3, provided that 1≦p+q≦4; and r is 0 or 1. X BI is a bromine atom or an iodine atom. R 1 and R 2 each independently represents a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, an amino 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, -N(R a )-C(=O)-R b , -N(R a )-C(=O)-OR b Or -N(R a )-S(=O)2-R b The hydrocarbyl group, the hydrocarbyloxy group, the hydrocarbyloxycarbonyl group and the hydrocarbylcarbonyloxy 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 and an ether bond. a 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. bis 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. X 1 is a single bond or -X 1A -R 3 -X 1B - X 1A and X 1B are each independently a single bond, an ether bond, an ester bond, a sulfonate ester bond, an amide bond, a urethane bond, a urea bond, a carbonate bond, or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain at least one bond selected from an ether bond and an ester bond. 3 is a hydrocarbylene group having 1 to 28 carbon atoms, and the hydrocarbylene may contain at least one atom selected from an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom. X 2 represents a single bond, an ether bond, an ester bond, or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain at least one bond selected from an ether bond and an ester bond. 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. M + is a sulfonium cation or an iodonium cation. 3. A resist material according to 1 or 2, further comprising a base polymer. 4. The resist material of 3, wherein the base polymer contains a repeating unit represented by the following formula (a1) or (a2): [ka] (In the formula, RA 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 bond selected from a single bond, a phenylene group, a naphthylene group, an ester bond, an ether 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 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 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is an integer from 0 to 4. 5. The resist material of 4, which is a chemically amplified positive resist material. 6. The resist material of 3, wherein the base polymer does not contain an acid labile group. 7. The resist material of 6, which is a chemically amplified negative resist material. 8. A resist material according to any one of 1 to 7, further comprising an organic solvent. 9. A resist material according to any one of 1 to 8, further comprising a quencher. 10. A resist material according to any one of 1 to 9, further comprising a surfactant. 11. A pattern forming method comprising the steps of forming a resist film on a substrate using a resist material according to any one of claims 1 to 10, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer. 12. The pattern formation method according to 11, wherein the high-energy radiation is ArF excimer laser light having a wavelength of 193 nm, KrF excimer laser light having a wavelength of 248 nm, EB or EUV having a wavelength of 3 to 15 nm. Effect of the Invention

[0013] Onium salts containing sulfonate anions in which two aromatic groups each having an iodine atom or a bromine atom are linked have the characteristics of high absorption of EUV light and suppressing acid diffusion. Therefore, by including the onium salt as an acid generator, it is possible to prevent a decrease in resolution due to blurring caused by acid diffusion, and to construct a resist material that is highly sensitive and has improved LWR and CDU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [Resist material] The resist material of the present invention contains an acid generator containing an onium salt containing a sulfonic acid anion in which two aromatic groups having iodine or bromine atoms are linked. The onium salt has high contrast and small acid diffusion due to the combination of the absorption of iodine atoms, the ionization of bromine atoms, and the high reactivity of sulfonic acid. This can improve LWR and CDU.

[0015] 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.

[0016] [Acid generator] The onium salt containing a sulfonate anion in which two aromatic groups each having an iodine atom or a bromine atom are linked together is preferably one represented by the following formula (1). [ka]

[0017] In formula (1), m is an integer of 1 to 5, and n is an integer of 0 to 4, provided that 1≦m+n≦5. p is an integer of 1 to 4, and q is an integer of 0 to 3, provided that 1≦p+q≦4. r is 0 or 1.

[0018] In formula (1), X BI is a bromine atom or an iodine atom.

[0019] In formula (1), R 1 and R 2 each independently represents a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, an amino 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, -N(R a )-C(=O)-R b , -N(R a )-C(=O)-OR b Or -N(R a )-S(=O)2-R b The hydrocarbyl group, the hydrocarbyloxy group, the hydrocarbyloxycarbonyl group and the hydrocarbylcarbonyloxy 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 and an ether bond. a 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. b 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.

[0020] R 1 and R 2The hydrocarbyl group represented by the formula (I) and the hydrocarbyl moiety of the hydrocarbyloxy group, hydrocarbyloxycarbonyl group and hydrocarbylcarbonyloxy 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.

[0021] In formula (1), X 1 is a single bond or -X 1A -R 3 -X 1B - X 1A and X 1Bare each independently a single bond, an ether bond, an ester bond, a sulfonate ester bond, an amide bond, a urethane bond, a urea bond, a carbonate bond, or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain at least one bond selected from an ether bond and an ester bond. 1 As -X 1A -R 3 -X 1B - is preferred, -X 1A -R 3 -X 1B - and X 1A and X 1B More preferably, at least one of X is an ether bond, an ester bond, a sulfonate ester bond, an amide bond, a urethane bond, a urea bond or a carbonate bond, 1A and X 1B More preferably, X is an ether bond, an ester bond, a sulfonate ester bond, an amide bond, a urethane bond, a urea bond or a carbonate bond. 1A and X 1B may be the same as or different from each other.

[0022] R 3is a hydrocarbylene group having 1 to 28 carbon atoms, which may contain at least one atom selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic.Specific examples thereof include ethane-1,1-diyl group, ethane-1,2-diyl group, 1-methylethane-1,2-diyl group, 1-ethylethane-1,2-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, butane-1,3-diyl group, butane-1,4-diyl group, 1,1-dimethylpropane-1,3-diyl group, 2,2-dimethylpropane-1,3-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, and octane-1,8-diyl group. alkanediyl groups having 1 to 28 carbon atoms, such as 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, a heptadecane-1,17-diyl group, an octadecane-1,18-diyl group, a nonadecane-1,19-diyl group, or an icosane-1,20-diyl group; a cyclopentanediyl group, a cyclohexanediyl group, a bicyclo[ cyclic saturated hydrocarbylene groups having 3 to 28 carbon atoms, such as 2.2.2]octanediyl group, norbornanediyl group, and adamantanediyl group; alkenediyl groups having 2 to 28 carbon atoms, such as ethenediyl group, propenediyl group, and butenediyl group; alkynediyl groups having 2 to 28 carbon atoms, such as ethynediyl group, propynediyl group, and butynediyl group; cyclic unsaturated aliphatic hydrocarbylene groups having 3 to 28 carbon atoms, such as cyclohexenediyl group, bicyclo[2.2.2]octenediyl group, and norbornenediyl group; phenylene group, methylphenylene group, ethylphenylene group, arylene groups having 6 to 28 carbon atoms, such as an arylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, tert-butylnaphthylene group, and anthracenediyl group; and groups obtained by combining these.

[0023] R3 As the alkyl group, an alkanediyl group having 1 to 28 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom, or an arylene group having 6 to 28 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom, is preferred, an alkanediyl group having 1 to 12 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom, or an arylene group having 6 to 12 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom, is more preferred, and an alkanediyl group having 1 to 6 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom, or an arylene group having 6 to 10 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom is even more preferred.

[0024] X 1 As -X 1A -R 3 -X 1B - is preferred, -X 1A -R 3 -X 1B - and X 1A and X 1B At least one of R is an ether bond, an ester bond, a sulfonate ester bond, an amide bond, a urethane bond, a urea bond, or a carbonate bond, 3 is more preferably an alkanediyl group having 1 to 28 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom, or an arylene group having 6 to 28 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom, 1A -R 3 -X 1B - and X 1A and X 1B are each independently an ether bond, an ester bond, a sulfonate ester bond, an amide bond, a urethane bond, a urea bond, or a carbonate bond; R 3is more preferably an alkanediyl group having 1 to 28 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom, or an arylene group having 6 to 28 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom, 1A -R 3 -X 1B - and X 1A and X 1B are each independently an ether bond, an ester bond, a sulfonate ester bond, an amide bond, a urethane bond, a urea bond, or a carbonate bond; R 3 is more preferably an alkanediyl group having 1 to 12 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom, or an arylene group having 6 to 12 carbon atoms which may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.

[0025] In formula (1), X 2 represents a single bond, an ether bond, an ester bond, or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain at least one bond selected from an ether bond and an ester bond.

[0026] In formula (1), 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.

[0027] Specific examples of the anion of the onium salt include, but are not limited to, those shown below. [ka]

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[0068] 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]

[0069] In formulas (2) and (3), R 4 ~R8 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0070] R 4 ~R 8 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.

[0071] R 4 ~R 8 The 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.

[0072] 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.

[0073] 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 lines represent bonds.)

[0074] M + Specific examples of the sulfonium cation represented by the formula (I) include, but are not limited to, those shown below. [ka]

[0075] [ka]

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[0110] M + Specific examples of the iodonium cation represented by the formula (I) include, but are not limited to, those shown below. [ka]

[0111] [ka]

[0112] The onium salt can be synthesized, for example, by salt exchange of a sulfonium salt or iodonium salt containing a halide anion with an ammonium salt containing a sulfonate anion in which two aromatic groups having an iodine atom or a bromine atom are linked. Specific examples of the ion exchange method include the method described in JP 2022-059571 A.

[0113] 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.

[0114] [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]

[0115] In formulas (a1) and (a2), R A Each of Y is independently a hydrogen atom or a methyl group. 1Y is a linking group having 1 to 12 carbon atoms and containing at least one bond selected from a single bond, a phenylene group, a naphthylene group, an ester bond, an ether 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 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 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a represents an integer of 0 to 4.

[0116] 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]

[0117] [ka]

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[0119] 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]

[0120] R in the repeating units a1 and a2 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.

[0121] Typically, specific examples of the acid labile group include those represented by any of the following formulae (AL-1) to (AL-3). [ka] (In the formula, the dashed lines represent bonds.)

[0122] In formulas (AL-1) and (AL-2), R L1 and R L2 are 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.

[0123] In formula (AL-1), b is an integer of 0 to 10, and an integer of 1 to 5 is preferable.

[0124] 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 L4Any 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.

[0125] 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 preferred, and an alicyclic ring is particularly preferred.

[0126] 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]

[0127] 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]

[0128] [ka]

[0129] [ka]

[0130] [ka]

[0131] [ka]

[0132] [ka]

[0133] [ka]

[0134] [ka]

[0135] 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]

[0136] The base polymer may include repeat units e derived from styrene, vinyl naphthalene, vinyl anthracene, vinyl pyrene, methylene indane, vinyl pyridine, or vinyl carbazole.

[0137] The base polymer may contain a repeating unit f derived from an onium salt containing a polymerizable unsaturated bond. JP 2005-84365 A proposes a sulfonium salt or iodonium salt containing a polymerizable olefin that generates a specific sulfonic acid. JP 2006-178317 A proposes a sulfonium salt in which a sulfonic acid is directly bonded to the main chain.

[0138] 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]

[0139] 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, -Z31 -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. 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 hydroxy group, or a halogen atom.

[0140] 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 4 ~R 8Examples 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 4 and R 5 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, similar to those exemplified above.

[0141] 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.

[0142] 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]

[0143] 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.

[0144] In formula (f1-2), R 32 represents 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.

[0145] R 31 or R 32The 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.

[0146] 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.

[0147] Specific examples of the cation of the monomer that gives the repeating unit f1 include, but are not limited to, those shown below.A and M - is the same as above. [ka]

[0148] 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.

[0149] 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]

[0150] [ka]

[0151] [ka]

[0152] [ka]

[0153] [ka]

[0154] [ka]

[0155] [ka]

[0156] [ka]

[0157] [ka]

[0158] [ka]

[0159] [ka]

[0160] [ka]

[0161] [ka]

[0162] [ka]

[0163] Specific examples of monomers that provide the repeating unit f3 include, but are not limited to, those shown below. A is the same as above. [ka]

[0164] 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.

[0165] The base polymer for the positive resist material essentially contains a 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.

[0166] On the other hand, the base polymer for the negative resist material does not necessarily require an acid-labile group. Examples of such a base polymer include those containing the repeating unit b and further containing the repeating units c, d, e, and / or f as necessary. 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 the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Also, b + c + d + e + f = 1.0.

[0167] To synthesize the base polymer, for example, a monomer that provides the above-described repeating unit may be heated in an organic solvent with a radical polymerization initiator added thereto to perform polymerization.

[0168] Specific examples of organic solvents used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. Specific examples of polymerization initiators 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] The base polymer may include two or more polymers having different composition ratios, Mw, and Mw / Mn.

[0175] [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.

[0176] 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.

[0177] [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.

[0178] 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.

[0179] 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.

[0180] 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]

[0181] 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.

[0182] R 101The 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] 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.

[0187] 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]

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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 4 ~R 8 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0192] Specific examples of the compound represented by formula (7) include those described in JP-A-2017-219836 and JP-A-2021-91666.

[0193] 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.

[0194] 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, or carbonic acid can also be used as quenchers.

[0195] 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.

[0196] [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.

[0197] 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, more preferably 0.1 to 100 parts by mass, relative to 100 parts by mass of the base polymer.

[0198] 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.

[0199] 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.

[0200] 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.

[0201] 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.

[0202] Specific examples of the epoxy compound include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0203] 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.

[0204] 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.

[0205] 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.

[0206] Specific examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0207] Specific examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0208] 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.

[0209] 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.

[0210] 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 material 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. It may also be used.

[0211] 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.

[0212] [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.

[0213] 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.

[0214] 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.

[0215] 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.

[0216] 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.

[0217] 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.

[0218] 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.

[0219] 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.

[0220] 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.

[0221] 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.

[0222] Specific examples of the aromatic solvent include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0223] 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.

[0224] 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

[0225] 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.

[0226] The structures of the sulfonium salt or iodonium salt acid generators PAG-1 to PAG-13 used in the resist material are shown below. [ka]

[0227] [ka]

[0228] [ka]

[0229] [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]

[0230] [Examples 1 to 16, Comparative Examples 1 to 3] Preparation of resist materials and their evaluation (1) Preparation of resist material The components were dissolved in a solution according to the composition shown in Table 1, and the solution was filtered through a 0.2 μm filter to prepare a resist material.

[0231] In Table 1, the components are as follows. Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) EL (Ethyl lactate) DAA (Diacetone Alcohol)

[0232] Comparative acid generator: cPAG-1, cPAG-2 [ka]

[0233] Quencher: Q-1, Q-2 [ka]

[0234] (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 15 and Comparative Examples 1 and 2, and dot patterns with a size of 20 nm in Example 16 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 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.

[0235] [Table 1]

[0236] The results shown in Table 1 show that the resist material of the present invention, which contains, as an acid generator, an onium salt of a sulfonic acid in which two aromatic groups each having an iodine atom or a bromine atom are linearly linked, has high sensitivity and good CDU.

Claims

1. A resist material comprising an acid generator containing an onium salt of a sulfonic acid in which two aromatic groups each having an iodine atom or a bromine atom are linked.

2. The resist material according to claim 1 , wherein the onium salt is represented by the following formula (1): 【Chemistry 1】 (In the formula, m is an integer of 1 to 5, n is an integer of 0 to 4, provided that 1≦m+n≦5; p is an integer of 1 to 4, q is an integer of 0 to 3, provided that 1≦p+q≦4; and r is 0 or 1. X BI is a bromine atom or an iodine atom. R 1 and R 2 each independently represents a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, an amino 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, -N(R a )-C(=O)-R b , -N(R a )-C(=O)-O-R b Or -N(R a )-S(=O) 2 -R b The hydrocarbyl group, the hydrocarbyloxy group, the hydrocarbyloxycarbonyl group and the hydrocarbylcarbonyloxy 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 and an ether bond. a 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. b 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. X 1 is a single bond or -X 1A -R 3 -X 1B - is. 1A and X 1B are each independently a single bond, an ether bond, an ester bond, a sulfonate ester bond, an amide bond, a urethane bond, a urea bond, a carbonate bond, or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain at least one bond selected from an ether bond and an ester bond. 3 is a hydrocarbylene group having 1 to 28 carbon atoms, and the hydrocarbylene may contain at least one atom selected from an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom. X 2 represents a single bond, an ether bond, an ester bond, or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain at least one bond selected from an ether bond and an ester bond. 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. M + is a sulfonium cation or an iodonium cation.

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

4. The resist material according to claim 3 , 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. Y 1 is a linking group having 1 to 12 carbon atoms and containing at least one bond selected from a single bond, a phenylene group, a naphthylene group, an ester bond, an ether 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 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 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is an integer from 0 to 4.

5. 5. The resist material of claim 4 which is a chemically amplified positive resist material.

6. 4. The resist material of claim 3, wherein the base polymer does not contain an acid labile group.

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

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

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

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

11. 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 10; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

12. 12. The pattern forming method according to claim 11, 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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