Sulfonium salt, resist material, and pattern forming method

Abstract

To provide a resist material that has high sensitivity and improved LWR and CDU, regardless of whether it is a positive or negative type, and a patterning method using the same.SOLUTION: The present invention provides a sulfonium salt represented by the formula (1), and a resist material containing the sulfonium salt.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] As LSIs become more highly integrated and faster, pattern rules are becoming increasingly miniaturized. This is due to the growing popularity of 5G high-speed communications and artificial intelligence (AI), which requires high-performance devices to process these technologies. The most advanced miniaturization technology is extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm, which is currently used to mass-produce 5 nm node devices. Furthermore, the use of EUV lithography is being considered for next-generation 3 nm node and the 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. To ensure resolution in fine patterns with dimensions of 45 nm and smaller, it has been suggested that controlling acid diffusion is important, in addition to improving dissolution contrast, as has been proposed previously (Non-Patent Document 1). However, because chemically amplified resist materials increase sensitivity and contrast through acid diffusion, attempts to minimize acid diffusion by lowering the post-exposure bake (PEB) temperature or shortening the time result in significant decreases in sensitivity and contrast.

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

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

[0006] The acid-labile groups used in (meth)acrylate polymers for EUV and ArF resist materials undergo deprotection using a photoacid generator that generates sulfonic acid substituted with a fluorine atom at the α-position, but not with an acid generator that generates sulfonic acid or carboxylic acid not substituted with a fluorine atom at the α-position. When a sulfonium salt or iodonium salt that generates a sulfonic acid substituted with a fluorine atom at the α-position is mixed with a sulfonium salt or iodonium salt that generates a sulfonic acid not substituted with a fluorine atom at the α-position, the sulfonium salt or iodonium salt that generates a sulfonic acid not substituted with a fluorine atom at the α-position undergoes ion exchange with the sulfonic acid not substituted with a fluorine atom at the α-position. The sulfonic acid substituted with a fluorine atom at the α-position generated by light reverts to the sulfonium salt or iodonium salt through ion exchange, and the sulfonium salt or iodonium salt of the sulfonic acid or carboxylic acid not substituted with a fluorine atom at the α-position functions as a quencher. A resist material has been proposed that uses a sulfonium salt or iodonium salt that generates a carboxylic acid as a quencher (Patent Document 3).

[0007] Sulfonium salt-type quenchers that generate carboxylic acids have been proposed. In particular, sulfonium salts of salicylic acid, β-hydroxycarboxylic acid (Patent Document 4), salicylic acid derivatives (Patent Documents 5 and 6), fluorosalicylic acid (Patent Document 7), and hydroxynaphthoic acid (Patent Document 8), as well as sulfonium salts of thiolcarboxylic acid (Patent Document 9) have been proposed. In particular, salicylic acid is highly effective in suppressing acid diffusion due to the intramolecular hydrogen bond between the carboxylic acid and the hydroxy group.

[0008] Sulfonium salts combining a carboxylate anion with a phenyldibenzothiophenium cation substituted with a carbonyl group or an alkoxycarbonyl group have been proposed (Patent Document 10). Examples of the carboxylate anion include adamantanecarboxylic acid or its analogs, salicylic acid, and fluoroalkylcarboxylic acids. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-45311 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-178317 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-114431 [Patent Document 4] International Publication No. 2018 / 159560 [Patent Document 5] Japanese Patent Publication No. 2020-203984 [Patent Document 6] Japanese Patent Publication No. 2020-91404 [Patent Document 7] Japanese Patent Publication No. 2020-91312 [Patent Document 8] Japanese Patent Application Publication No. 2019-120760 [Patent Document 9] Japanese Patent Application Publication No. 2019-74588 [Patent Document 10] Patent Publication No. 2021-35937 [Non-patent literature]

[0010] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) Summary of the Invention [Problem to be solved by the invention]

[0011] In resist materials, it is desirable to develop a quencher that can improve line width write (LWR) and hole dimension uniformity (CDU) while also improving sensitivity. To achieve this, it is necessary to further reduce image blurring caused by acid diffusion.

[0012] The present invention has been made in view 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] As a result of extensive research to achieve the above object, the present inventors discovered that a sulfonium salt having a specific structure exhibits high decomposition efficiency upon exposure and high acid diffusion control ability, thereby enabling the production of a resist material with high sensitivity, improved LWR and CDU, excellent resolution, and a wide process margin, and thus completed the present invention.

[0014] That is, the present invention provides the following sulfonium salt, resist material, and pattern forming method. 1. A sulfonium salt represented by the following formula (1): [ka] In the formula, p, q, and r each independently represent an integer of 0 to 3, and s is 1 or 2, provided that 1≦r+s≦3. R 1 and R 2each independently represents a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a nitro group, a cyano group, or —C(═O)—R 4 , -OC(=O)-R 5 -OR 5 is. R 3 represents a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a nitro group, a cyano group, -OC(=O)-R 5 -OR 5 is. R 4 represents a hydrocarbyl group having 1 to 10 carbon atoms, a hydrocarbyloxy group having 1 to 10 carbon atoms, or -OR 4A The hydrocarbyl group and the hydrocarbyloxy group may be substituted with a fluorine atom or a hydroxy group. 4A is an acid labile group. R 5 is a hydrocarbyl group having 1 to 10 carbon atoms. X 1 is a single bond, an ether bond, a carbonyl group, —N(R)—, a sulfide bond or a sulfonyl group, and R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. Xq - is an anion represented by the following formula (2). [ka] (In the formula, R 6 is a single bond or an alkanediyl group having 1 to 4 carbon atoms. R 7A and R 7B are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, provided that at least one of them is a fluorine atom or a trifluoromethyl group. R 8 is a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. R 9is a linear or branched hydrocarbyl group having 6 to 20 carbon atoms which may contain a heteroatom, or a cyclic hydrocarbyl group having 3 to 20 carbon atoms which may contain a heteroatom. L 1 is an ether bond, an ester bond, a carbonate bond, or a urethane bond.)] 2.R 6 is a single bond, and R 7A and R 7B The sulfonium salt of 1, where is a fluorine atom. 3. A resist material containing a quencher containing a sulfonium salt of 1 or 2. 4. The resist material of 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 a repeating unit represented by the following formula (a2): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid labile group. R 13 is a fluorine atom, a trifluoromethyl group, a cyano group or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of the carbon atoms of which may be substituted with ether bonds or ester bonds. a is 1 or 2, and b is an integer from 0 to 4, provided that 1≦a+b≦5. 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. The resist material of any one of 4 to 8, wherein the base polymer contains at least one repeating unit selected from the repeating units represented by the following formulas (f1) to (f3): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. Z 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. Z 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)-. Z 31 represents an aliphatic hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, a urethane bond, a nitro group, a cyano group, a fluorine atom, an iodine atom, or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. Z 5represents 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. Z 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom, or a hydroxy group. R 21 ~R 28 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 and R 24 and R 26 and R 27 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. M - is a non-nucleophilic counterion. 10. The resist material of any one of 3 to 9, further comprising an acid generator that generates a strong acid. 11. The resist material of 10, wherein the acid generator generates a sulfonic acid, an imide acid, or a methide acid. 12. A resist material according to any one of 3 to 11, further comprising an organic solvent. 13. The resist material of any one of 3 to 12, further comprising a surfactant. 14. A pattern forming method comprising the steps of forming a resist film on a substrate using a resist material according to any one of 3 to 13, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer. 15. The pattern formation method of 14, wherein the high-energy beam is KrF excimer laser light, ArF excimer laser light, an electron beam (EB), or EUV having a wavelength of 3 to 15 nm. [Effects of the Invention]

[0015] The sulfonium salt of the present invention acts as a quencher in a resist material. This sulfonium salt has high acid diffusion control ability and can improve the solubility of the exposed area in a developer, making it possible to construct a resist material that has excellent sensitivity while improving LWR and CDU. DETAILED DESCRIPTION OF THE INVENTION

[0016] [Sulfonium salts] The sulfonium salt of the present invention (hereinafter also referred to as sulfonium salt A) is represented by the following formula (1). [ka]

[0017] In formula (1), p, q, and r each independently represent an integer of 0 to 3, and s is 1 or 2, provided that 1≦r+s≦3.

[0018] In formula (1), R 1 and R 2 each independently represents a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a nitro group, a cyano group, or —C(═O)—R 4 , -OC(=O)-R 5 -OR 5 is.

[0019] In formula (1), R 3 represents a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a nitro group, a cyano group, -OC(=O)-R 5 -OR 5 is.

[0020] In formula (1), R 4 represents a hydrocarbyl group having 1 to 10 carbon atoms, a hydrocarbyloxy group having 1 to 10 carbon atoms, or -OR 4A The hydrocarbyl group and the hydrocarbyloxy group may be substituted with a fluorine atom or a hydroxy group. 4A is an acid labile group.

[0021] In formula (1), R 5 is a hydrocarbyl group having 1 to 10 carbon atoms.

[0022] R 4 and R 5 and hydrocarbyl groups represented by R 4The hydrocarbyl moiety of the hydrocarbyloxy group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, 3-pentyl, tert-pentyl, neopentyl, n-hexyl, n-octyl, n-nonyl, and n-decyl groups; cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, norbornyl, and cyclopropyl. cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms, such as cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl, cyclobutylethyl, cyclopentylmethyl, cyclopentylethyl, cyclohexylmethyl, cyclohexylethyl, methylcyclopropyl, methylcyclobutyl, methylcyclopentyl, methylcyclohexyl, ethylcyclopropyl, ethylcyclobutyl, ethylcyclopentyl, and ethylcyclohexyl groups; vinyl groups, 1-propenyl groups, and the like; alkenyl groups having 2 to 10 carbon atoms, such as ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, and decenyl groups; alkynyl groups having 2 to 10 carbon atoms, such as ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, and decynyl groups; cyclopentenyl, cyclohexenyl, methylcyclopentenyl, methylcyclohexenyl, ethylcyclopentenyl, ethylcyclohexenyl, norborn ...pentenyl, ethylcyclohexenyl, ethylcyclopentenyl, Examples of the alkyl group include: cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 10 carbon atoms, such as a naphthyl group; aryl groups having 6 to 10 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, and a naphthyl group; aralkyl groups having 7 to 10 carbon atoms, such as a benzyl group, a phenethyl group, a phenylpropyl group, and a phenylbutyl group; and groups obtained by combining these groups.

[0023] R 4AExamples of the acid labile group represented by the formula (AL-1) include the acid labile groups represented by the formulas (AL-1) to (AL-3) described below.

[0024] In formula (1), X 1 is a single bond, an ether bond, a carbonyl group, —N(R)—, a sulfide bond or a sulfonyl group, and R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms.

[0025] Examples of the cation of the sulfonium salt represented by formula (1) include, but are not limited to, those shown below. [ka]

[0026] [ka]

[0027] [ka]

[0028] [ka]

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] The sulfonium cation is preferably a dibenzothiophenium salt, i.e., X in formula (1) 1 is a single bond, which is particularly suitable for EUV lithography due to its high photodecomposition efficiency. More preferably, the substituent of the cation is an ester bond, that is, R 4 In this case, the ester moiety is hydrolyzed particularly during alkaline development, improving the solubility of the exposed area and suppressing residual defects.

[0035] In formula (1), Xq - is an anion represented by the following formula (2). [ka]

[0036] In formula (2), R 6 is a single bond or an alkanediyl group having 1 to 4 carbon atoms. Examples of the alkanediyl group include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, and a butane-1,4-diyl group.

[0037] In formula (2), R 7A and R 7B are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, provided that at least one of them is a fluorine atom or a trifluoromethyl group.

[0038] In formula (2), R 8is a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups having 1 to 20 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, and dodecane-1,12-diyl group; cyclic saturated alkyl groups having 3 to 20 carbon atoms, such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group. aryl groups having 6 to 20 carbon atoms such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group, an isobutylphenylene group, a sec-butylphenylene group, a tert-butylphenylene group, a naphthylene group, a methylnaphthylene group, an ethylnaphthylene group, an n-propylnaphthylene group, an isopropylnaphthylene group, an n-butylnaphthylene group, an isobutylnaphthylene group, a sec-butylnaphthylene group, or a tert-butylnaphthylene group; and groups obtained by combining these. In addition, some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, or some of the -CH- groups of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbylene group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0039] Also, R 8 As the group, a group represented by the following formula (2)-1 is also preferred. [ka] (where * represents R 7A and R 7B is the bond to the carbon atom to which it is bonded. ** is the bond to the carbon atom to which it is bonded. 1 )

[0040] In formula (2)-1, R 8A and R 8B are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. 8A and R 8B may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 4 and R 5 Examples include the same as those exemplified as the hydrocarbyl group represented by the formula: 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- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0041] In formula (2)-1, R 8C is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 8Among the examples of hydrocarbylene groups represented by the formula (I), those having 1 to 10 carbon atoms can be mentioned. Some or all of the hydrogen atoms of the hydrocarbylene group can 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- groups of the hydrocarbylene group can be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, so that the hydrocarbylene group can contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0042] The group represented by formula (2)-1 contains 20 or less carbon atoms.

[0043] In formula (2), R 9is a linear or branched hydrocarbyl group having 6 to 20 carbon atoms which may contain a heteroatom, or a cyclic hydrocarbyl group having 3 to 20 carbon atoms which may contain a heteroatom. Examples of the linear or branched hydrocarbyl group having 6 to 20 carbon atoms include alkyl groups having 6 to 20 carbon atoms such as hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl. Examples of the cyclic hydrocarbyl group having 3 to 20 carbon atoms include saturated cyclic 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, and an adamantyl group; unsaturated cyclic aliphatic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexenyl group and a norbornenyl group; aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, and a tert-butylnaphthyl group; and groups obtained by combining these groups.

[0044] In formula (2), L 1 is an ether bond, an ester bond, a carbonate bond or a urethane bond.

[0045] The anion represented by formula (2) is R 6 is a single bond, and R 7A and R 7B is preferably a fluorine atom.

[0046] Examples of the anion represented by formula (2) include, but are not limited to, those shown below. [ka]

[0047] [ka]

[0048] Specific examples of the sulfonium salt A include any combination of the specific examples of the cations and the specific examples of the anions mentioned above.

[0049] The sulfonium salt A can be synthesized, for example, by ion-exchanging a sulfonium salt having the sulfonium cation with an ammonium salt of the anion or a protonic acid of the anion. The sulfonium cation can be obtained by reacting the corresponding sulfide compound with a diphenyliodonium salt.

[0050] [Resist materials] The resist material of the present invention is characterized by containing a quencher containing a sulfonium salt A.

[0051] In the resist material of the present invention, sulfonium salt A functions as a quencher. By using sulfonium salt A, the resist material of the present invention exhibits highly controlled acid diffusion, resulting in excellent lithography performance in terms of LWR and CDU. Furthermore, despite the low acid diffusion, the resist material also exhibits excellent sensitivity and contrast. While the reason for this is unclear, the following mechanism is thought to be one of the possible explanations.

[0052] Sulfonium salt A has a carbonyl group in the cation, and this oxygen atom is thought to interact with the acid generated from the photoacid generator to control diffusion. In addition, sulfonium salt A has a fused ring structure via a sulfur atom, and the large strain results in high photodecomposition efficiency, i.e., high sensitivity. While fused-ring sulfide structures that are thought to be generated after decomposition generally have low solubility in alkaline developers, sulfonium salt A has a carbonyl group and moderate polarity, resulting in high developer affinity and less residue defects. In particular, sulfonium salt A containing an ester bond is hydrolyzed during development, making it more soluble in the developer (Scheme 1). In addition, the position of the carbonyl group or ester bond is also important for the sulfonium salt of the present invention. As shown in Scheme 1, the location of these functional groups at the fused ring site ensures the solubility of the photodecomposed sulfide compound. On the other hand, when the functional group is present at a non-fused ring site, the decomposed sulfide compound has low solubility in alkaline developers, which can lead to defects. [ka] (In the formula, M - and X 1 is the same as above. Ra is a hydrocarbyl group.

[0053] For example, as shown in Scheme 2, in the case of a dibenzothiophenium salt (i.e., when X is a single bond), the dibenzothiophene that is presumed to be produced by photolysis is sparingly soluble in an alkaline developer. [ka] (In the formula, M - and Ra is the same as above.)

[0054] The anion structure of sulfonium salt A is also believed to contribute to the lithography performance of the resist material of the present invention. The anion has a carboxylate structure containing a fluorine atom, which provides moderate acidity. Furthermore, the presence of a bulky hydrocarbyl group is expected to suppress acid diffusion. Therefore, it is believed that a resist material with an excellent balance of sensitivity, roughness, and resolution has been achieved. In particular, in EUV lithography, the use of an anion containing an iodine atom, which has high absorption of EUV light, can further improve the lithography performance.

[0055] In the resist material of the present invention, the content of sulfonium salt A is preferably 0.001 to 50 parts by mass, and more preferably 0.01 to 40 parts by mass, per 100 parts by mass of the base polymer described below. The sulfonium salt A may be used alone or in combination of two or more types.

[0056] [Base polymer] The resist material of the present invention may contain a base polymer. In the case of a positive resist material, the base polymer contains a repeating unit containing an acid labile group. The repeating unit containing an acid labile group is preferably a repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1) or a repeating unit represented by the following formula (a2) (hereinafter also referred to as repeating unit a2). [ka]

[0057] In formulas (a1) and (a2), R A are each independently a hydrogen atom or a methyl group. 1 Y is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. 2 is a single bond or an ester bond. 3 is a single bond, an ether bond, or an ester bond. 11 and R 12are each independently an acid labile group. When the base polymer contains both the repeating unit a1 and the repeating unit a2, R 11 and R 12 R may be the same or different. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of the carbon atoms of which may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4, provided that 1≦a+b≦5.

[0058] Examples of monomers that provide the repeating unit a1 include, but are not limited to, the following: A and R 11 is the same as above. [ka]

[0059] Examples of the monomer that provides the repeating unit a2 include, but are not limited to, the following: A and R 12 is the same as above. [ka]

[0060] In formulas (1), (a1) and (a2), R 4A , R 11 and R 12 Examples of the acid labile group represented by the formula (I) include those described in JP-A Nos. 2013-80033 and 2013-83821.

[0061] Typical examples of the acid labile group include those represented by the following formulae (AL-1) to (AL-3). [ka] (In the formula, the dashed lines represent bonds.)

[0062] 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.

[0063] In formula (AL-1), c is an integer of 0 to 10, and an integer of 1 to 5 is preferred.

[0064] 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 heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. 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. In addition, R L2 , R L3 and R L4 Any two of these may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0065] 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. In addition, R L5 , RL6 and R L7 Any two of these may be bonded to each other together with the carbon atoms to which they are bonded to form 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.

[0066] The base polymer may contain a repeating unit b containing a phenolic hydroxy group as an adhesive group. Examples of monomers that provide the repeating unit b include, but are not limited to, the following. In the following formula, R A is the same as above. [ka]

[0067] [ka]

[0068] [ka]

[0069] The base polymer may contain a repeating unit c containing, as another adhesive group, a hydroxy group other than a phenolic hydroxy group, a lactone ring, a sultone ring, an ether bond, an ester bond, a sulfonate ester bond, a carbonyl group, a sulfonyl group, a cyano group, or a carboxy group. Examples of monomers that provide the repeating unit c include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0070] [ka]

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] The base polymer may contain repeating units d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or derivatives thereof. Monomers that provide repeating units d include, but are not limited to, the following: [ka]

[0079] The base polymer may include repeat units e derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindane, vinylpyridine, or vinylcarbazole.

[0080] The base polymer may contain a repeating unit f derived from an onium salt containing a polymerizable unsaturated bond. Preferred repeating units f include a repeating unit represented by the following formula (f1) (hereinafter also referred to as repeating unit f1), a repeating unit represented by the following formula (f2) (hereinafter also referred to as repeating unit f2), and a repeating unit represented by the following formula (f3) (hereinafter also referred to as repeating unit f3). The repeating units f1 to f3 may be used alone or in combination of two or more. [ka]

[0081] 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, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. Z 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, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy 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 represents an aliphatic hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. 5represents 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. Z 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom, or a hydroxy group.

[0082] 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. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples of the halogen atom and hydrocarbyl group include those described in the description of formulas (3-1) and (3-2) below. 101 ~R 105 Examples of the halogen atom and hydrocarbyl group include those exemplified as those represented by the formula (I). 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, etc. 23 and R 24 or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring may be any of the rings described below with reference to R 101 and R 102and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

[0083] In formula (f1), M - is a non-nucleophilic counter ion. Examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion; fluoroalkylsulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion and nonafluorobutanesulfonate ion; arylsulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion and 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as mesylate ion and butanesulfonate ion; imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion and bis(perfluorobutylsulfonyl)imide ion; and methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0084] Other examples of the non-nucleophilic counter ion include a sulfonate ion represented by the following formula (f1-1) in which the α-position is substituted with a fluorine atom, and a sulfonate ion represented by the following formula (f1-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group. [ka]

[0085] In formula (f1-1), R 31 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A') described below. fa1 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0086] In formula (f1-2), R 32 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbyl carbonyl group having 6 to 20 carbon atoms, and the hydrocarbyl group and the hydrocarbyl carbonyl group may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl moiety of the hydrocarbyl group and the hydrocarbyl carbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A') described below. fa1 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0087] Examples of the cation of the monomer that gives the repeating unit f1 include, but are not limited to, the following: A is the same as above. [ka]

[0088] Specific examples of the cation of the monomer that gives the repeating unit f2 or f3 include the sulfonium cation represented by formula (1) and the same as those exemplified as the cation of the sulfonium salt represented by formula (3-1) described later.

[0089] Examples of the anion of the monomer that gives the repeating unit f2 include, but are not limited to, those shown below. A is the same as above. [ka]

[0090] [ka]

[0091] [ka]

[0092]

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[0093]

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[0094]

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[0095]

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[0096]

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[0097]

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[0098]

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[0099]

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[0100]

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[0101]

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[0102]

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[0103]

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[0104]

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[0105]

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[0106]

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[0107]

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[0108]

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[0109]

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[0110]

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[0111]

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[0112]

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[0113]

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[0114]

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[0115]

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[0116]

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[0117]

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[0118]

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[0119]

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[0120]

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[0121]

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[0122]

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[0123]

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[0124]

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[0125]

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[0126]

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[0127]

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[0128]

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[0129]

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[0130]

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[0131]

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[0132]

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[0133]

change

[0134] [ka]

[0135] [ka]

[0136] [ka]

[0137] [ka]

[0138] [ka]

[0139] Examples of the anion of the monomer that gives the repeating unit f3 include, but are not limited to, those shown below. A is the same as above. [ka]

[0140] 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, preventing a decrease in resolution due to blurring caused by acid diffusion. Furthermore, the uniform dispersion of the acid generator improves LWR and CDU. When a base polymer containing the repeating unit f is used, the addition of an additive-type acid generator, which will be described later, can be omitted.

[0141] In the base polymer, the content ratios of the repeating units a1, a2, b, c, d, e, f1, f2 and f3 are preferably 0≦a1≦0.9, 0≦a2≦0.9, 0≦a1+a2≦0.9, 0≦b≦0.9, 0≦c≦0.9, 0≦d≦0.5, 0≦e≦0.5, 0≦f1≦0.5, 0≦f2≦0.5, 0≦f3≦0.5, 0≦f1+f2+f3≦0.5, and more preferably 0≦a1≦0.8, 0≦a2≦0.8, 0≦a1+a2≦0.8, 0≦f1+a2≦0.8, 0≦f1+f2≦0.8 ≦b≦0.8, 0≦c≦0.8, 0≦d≦0.4, 0≦e≦0.4, 0≦f1≦0.4, 0≦f2≦0.4, 0≦f3≦0.4, and 0≦f1+f2+f3≦0.4 are more preferred, and 0≦a1≦0.7, 0≦a2≦0.7, 0≦a1+a2≦0.7, 0≦b≦0.7, 0≦c≦0.7, 0≦d≦0.3, 0≦e≦0.3, 0≦f1≦0.3, 0≦f2≦0.3, 0≦f3≦0.3, and 0≦f1+f2+f3≦0.3 are even more preferred, provided that a1+a2+b+c+d+f1+f2+f3+e=1.0.

[0142] The base polymer can be synthesized, for example, by polymerizing a monomer that provides the repeating unit described above in an organic solvent with the addition of a radical polymerization initiator by heating.

[0143] Examples of organic solvents used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. 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 polymerization temperature is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, and more preferably 5 to 20 hours.

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

[0145] When hydroxystyrene or hydroxyvinylnaphthalene is copolymerized, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group may be deprotected by the alkaline hydrolysis to give hydroxystyrene or hydroxyvinylnaphthalene.

[0146] The base that can be used in alkaline hydrolysis includes aqueous ammonia, triethylamine, etc. The reaction temperature is preferably −20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0147] The base polymer preferably has a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) using THF as a solvent of 1,000 to 500,000, more preferably 2,000 to 30,000. When the Mw is within this range, the resist film has good heat resistance and solubility in an alkaline developer.

[0148] Furthermore, if the base polymer has a broad molecular weight distribution (Mw / Mn), the presence of low-molecular-weight and high-molecular-weight polymers may result in the appearance of foreign matter on the pattern after exposure, or the pattern shape may be deteriorated. As the pattern rule becomes finer, the effects of Mw and Mw / Mn tend to become greater. Therefore, in order to obtain a resist material that is suitable for use with fine pattern dimensions, it is preferable that the Mw / Mn of the base polymer has a narrow distribution of 1.0 to 2.0, particularly 1.0 to 1.5.

[0149] The base polymer may contain two or more polymers with different composition ratios, Mw, and Mw / Mn.

[0150] [Acid generator] The resist material of the present invention may contain an acid generator (hereinafter also referred to as an additive acid generator) that generates a strong acid. In this context, the term "strong acid" refers to a compound that has sufficient acidity to cause a deprotection reaction of acid-labile groups in the base polymer in the case of a chemically amplified positive resist material, and to a compound that has sufficient acidity to cause an acid-induced polarity change reaction or crosslinking reaction in the case of a chemically amplified negative resist material. By including such an acid generator, the sulfonium salt functions as a quencher, allowing the resist material of the present invention to function as either a chemically amplified positive resist material or a chemically amplified negative resist material.

[0151] Examples of the acid generator include compounds (photoacid generators) that generate acid in response to actinic rays or radiation. The photoacid generator may be any compound that generates an acid upon exposure to high-energy rays, but is preferably one that generates a sulfonic acid, an imide acid, or a methide acid. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators. Specific examples of photoacid generators include those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A.

[0152] Furthermore, as the photoacid generator, a sulfonium salt represented by the following formula (3-1) or an iodonium salt represented by the following formula (3-2) can also be suitably used. [ka]

[0153] In formulas (3-1) and (3-2), R 101 ~R 105 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0154] R 101 ~R 105Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0155] R 101 ~R 105 The hydrocarbyl group having 1 to 20 carbon atoms 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 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl groups; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, propenyl, butenyl, and hexenyl groups; and ethynyl groups. 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, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group 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.

[0156] Furthermore, 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 -CH- groups 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.

[0157] Also, R 101 and R 102 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring preferably has the following structure: [ka] (In the formula, the dashed line indicates R 103 )

[0158] Examples of the cation of the sulfonium salt represented by formula (3-1) include, but are not limited to, those shown below. [ka]

[0159] [ka]

[0160] [ka]

[0161] [ka]

[0162]

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[0163]

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[0164]

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[0165]

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[0166]

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[0167]

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[0168]

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[0169]

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[0170]

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[0171]

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[0172]

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[0173] [ka]

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] [ka]

[0178] [ka]

[0179] [ka]

[0180] [ka]

[0181] [ka]

[0182] As the cation of the sulfonium salt represented by formula (3-1), a cation represented by formula (1) can also be used.

[0183] Examples of the cation of the iodonium salt represented by formula (3-2) include, but are not limited to, the following: [ka]

[0184] [ka]

[0185] In formulas (3-1) and (3-2), Xa - is an anion selected from the following formulae (3A) to (3D). [ka]

[0186] In formula (3A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A') described below. fa1 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0187] The anion represented by formula (3A) is preferably one represented by the following formula (3A'). [ka]

[0188] In formula (3A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. fa1is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, or the like, and more preferably an oxygen atom. In order to obtain high resolution in the formation of a fine pattern, the hydrocarbyl group is particularly preferably one having 6 to 30 carbon atoms.

[0189] R fa1 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosyl groups; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, and norbornyl. Examples of such groups include saturated cyclic hydrocarbyl groups having 3 to 38 carbon atoms, such as an allyl group, a norbornylmethyl group, a tricyclodecyl group, a tetracyclododecyl group, a tetracyclododecylmethyl group, and a dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 38 carbon atoms, such as an allyl group and a 3-cyclohexenyl group; aryl groups having 6 to 38 carbon atoms, such as a phenyl group, a 1-naphthyl group, and a 2-naphthyl group; aralkyl groups having 7 to 38 carbon atoms, such as a benzyl group and a diphenylmethyl group; and groups obtained by combining these groups.

[0190] Furthermore, 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 -CH- groups 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, etc. Examples of hydrocarbyl groups containing hetero atoms include tetrahydrofuryl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, and 3-oxocyclohexyl groups.

[0191] Synthesis of sulfonium salts containing anions represented by formula (3A') is described in detail in JP-A Nos. 2007-145797, 2008-106045, 2009-7327, and 2009-258695. Sulfonium salts described in JP-A Nos. 2010-215608, 2012-41320, 2012-106986, and 2012-153644 are also suitable.

[0192] Examples of the anion represented by formula (3A) include the same anions as those exemplified as the anion represented by formula (1A) in JP 2018-197853 A.

[0193] In formula (3B), R fb1 and R fb2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). fa1Examples of the hydrocarbyl group represented by R include the same as those exemplified above. fb1 and R fb2 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 means that the groups to which they are bonded (-CF2-SO2-N - -SO2-CF2-) together to form a ring, in which case, R fb1 and R fb2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0194] In formula (3C), R fc1 , R fc2 and R fc3 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). fa1 Examples of the hydrocarbyl group represented by R include the same as those exemplified above. fc1 , R fc2 and R fc3 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 are groups that are bonded together and bonded to each other (-CF2-SO2-C - -SO2-CF2-) together to form a ring, in which case, R fc1 and R fc2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0195] In formula (3D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). fa1Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0196] The synthesis of sulfonium salts containing anions represented by formula (3D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

[0197] Examples of the anion represented by formula (3D) include the same anions as those exemplified as the anion represented by formula (1D) in JP 2018-197853 A.

[0198] Although the photoacid generator containing the anion represented by formula (3D) does not have a fluorine atom at the α-position of the sulfo group, it has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave the acid labile groups in the base polymer, making it suitable for use as a photoacid generator.

[0199] As the photoacid generator, a compound represented by the following formula (4) can also be suitably used. [ka]

[0200] In formula (4), R 201 and R 202 R are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 201 , R 202 and R 203 Any two of these 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 the same as R 101 and R 102 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, similar to the rings exemplified above.

[0201] R201 and R 202 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, an oxanorbornyl group, and a tricyclo[5.2.1.0] 2,6 cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as a decyl group and an adamantyl group; aryl groups having 6 to 30 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, a tert-butylnaphthyl group and an anthracenyl group; and groups obtained by combining these groups. Furthermore, 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 -CH- groups 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, etc.

[0202] R 203The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups having 1 to 30 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, and heptadecane-1,17-diyl group; cyclopentanediyl group, cyclohexene-1,18-diyl group, and the like. Examples of the alkylene groups include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as xanediyl, norbornanediyl, and adamantanediyl; arylene groups having 6 to 30 carbon atoms, such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, and tert-butylnaphthylene; and groups obtained by combining these groups. In addition, some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH- groups of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the hydrocarbylene group containing a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. As the heteroatom, an oxygen atom is preferred.

[0203] In formula (4), LA is a single bond, an ether bond, or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 203 Examples of the hydrocarbylene group represented by the formula (I) include the same as those exemplified above.

[0204] In formula (4), X A , X B , X C and X D are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that X A , X B , X C and X D At least one of the groups is a fluorine atom or a trifluoromethyl group.

[0205] In the formula (4), d is an integer of 0 to 3.

[0206] The photoacid generator represented by formula (4) is preferably one represented by the following formula (4'). [ka]

[0207] In formula (4'), L A is the same as above. R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). fa1 Examples of the hydrocarbyl group include the same as those exemplified above. Each of x and y is independently an integer of 0 to 5, and z is an integer of 0 to 4.

[0208] Examples of the photoacid generator represented by formula (4) include the same compounds as those exemplified as the photoacid generator represented by formula (2) in JP-A-2017-26980.

[0209] Among the photoacid generators, those containing an anion represented by formula (3A') or (3D) are particularly preferred because of their small acid diffusion and excellent solubility in solvents. Also, those represented by formula (4') are particularly preferred because of their extremely small acid diffusion.

[0210] The photoacid generator may also be a sulfonium salt or iodonium salt containing an anion having an aromatic ring substituted with an iodine atom or a bromine atom, such as those represented by the following formula (5-1) or (5-2): [ka]

[0211] In formulas (5-1) and (5-2), p' is an integer that satisfies 1≦p'≦3. q' and r' are integers that satisfy 1≦q'≦5, 0≦r'≦3, and 1≦q'+r'≦5. q' is preferably an integer that satisfies 1≦q'≦3, more preferably 2 or 3. r' is preferably an integer that satisfies 0≦r'≦2.

[0212] In formulas (5-1) and (5-2), X BI is an iodine atom or a bromine atom, and when p' and / or q' are 2 or more, they may be the same or different.

[0213] In formulas (5-1) and (5-2), L 1 is a single bond, an ether bond, an ester bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0214] In formulas (5-1) and (5-2), L 2represents a single bond or a divalent linking group having 1 to 20 carbon atoms when p' is 1, and represents a (p'+1)-valent linking group having 1 to 20 carbon atoms when p' is 2 or 3, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0215] In formulas (5-1) and (5-2), R 401 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms or a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond, or 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-OR 401D R 401A and R 401B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 401C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 401Dis an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyl group, and hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When p' and / or r' is 2 or more, each R 401 may be the same or different from each other.

[0216] Of these, R 401 Examples of the hydroxyl group include -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-OR 401D fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, etc. are preferred.

[0217] In formulas (5-1) and (5-2), Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine to form a carbonyl group. 3 and Rf 4 are preferably both fluorine atoms.

[0218] In formulas (5-1) and (5-2), R 402 ~R 406 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 R101 ~R 105 Examples of the hydrocarbyl group include the same as those exemplified above. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone ring, a sulfo group, or a sulfonium salt-containing group, and some of the -CH2- groups of the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate ester bond. 402 and R 403 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is the same as that described in the explanation of formula (3-1) as R 101 and R 102 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, similar to the rings exemplified above.

[0219] Examples of the cation of the sulfonium salt represented by formula (5-1) include the same as those exemplified as the cation of the sulfonium salt represented by formula (3-1). Examples of the cation of the iodonium salt represented by formula (3-2) include the same as those exemplified as the cation of the iodonium salt represented by formula (3-2).

[0220] Examples of the anion of the onium salt represented by formula (5-1) or (5-2) include, but are not limited to, those shown below. BI is the same as above. [ka]

[0221] [ka]

[0222] [ka]

[0223]

change

[0224]

change

[0225]

change

[0226]

change

[0227]

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[0228]

change

[0229]

change

[0230]

change

[0231]

change

[0232]

change

[0233]

change

[0234]

change

[0235]

change

[0236]

change

[0237]

change

[0238]

change

[0239]

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[0240]

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[0241]

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[0242]

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[0243] When the resist material of the present invention contains an additive acid generator, the amount thereof is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, per 100 parts by mass of the base polymer. When the base polymer contains any of the repeating units f1 to f3 and / or the resist material contains an additive acid generator, the resist material of the present invention can function as a chemically amplified resist material.

[0244] [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 components described above and below. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] and

[0145] of JP-A No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol Examples of the esters include propylene glycol monoethyl 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, propylene glycol mono-tert-butyl ether acetate, and lactones such as γ-butyrolactone.

[0245] In the resist composition 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, per 100 parts by mass of the base polymer. The organic solvents may be used singly or in combination of two or more.

[0246] [Other ingredients] In addition to the components described above, the resist material of the present invention may also contain surfactants, dissolution inhibitors, crosslinking agents, quenchers other than the sulfonium salts described above (hereinafter referred to as "other quenchers"), water repellency improvers, acetylene alcohols, etc.

[0247] Examples of the surfactant include those described in paragraphs

[0165] and

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

[0248] When the resist material of the present invention is a positive resist, the incorporation of a dissolution inhibitor can further increase the difference in dissolution rate between exposed and unexposed areas, thereby further improving resolution. Examples of dissolution inhibitors include compounds having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800, containing two or more phenolic hydroxy groups in the molecule, in which the hydrogen atoms of the phenolic hydroxy groups have been substituted with acid labile groups at a rate of 0 to 100 mol % overall, and compounds containing carboxy groups in the molecule, in which the hydrogen atoms of the carboxy groups have been substituted with acid labile groups at an average rate of 50 to 100 mol % overall. Specific examples include compounds in which the hydrogen atoms of the hydroxyl groups or carboxyl groups of bisphenol A, trisphenol, phenolphthalein, cresol novolak, naphthalenecarboxylic acid, adamantanecarboxylic acid, and cholic acid have been substituted with acid labile groups. These compounds are described, for example, in paragraphs

[0155] to

[0178] of JP 2008-122932 A.

[0249] When the resist composition of the present invention is a positive resist composition and contains the dissolution inhibitor, the content thereof is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, per 100 parts by mass of the base polymer. The dissolution inhibitor may be used alone or in combination of two or more types.

[0250] On the other hand, when the resist material of the present invention is negative-working, a negative pattern can be obtained by adding a crosslinking agent to reduce the dissolution rate of the exposed area. Examples of crosslinking agents 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, all 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 polymer side chains. Hydroxy-containing compounds may also be used as crosslinking agents.

[0251] Examples of the epoxy compound include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0252] Examples of the melamine compound include hexamethylol melamine, hexamethoxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are methoxymethylated, or a mixture thereof, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are acyloxymethylated, or a mixture thereof.

[0253] Examples of the guanamine compound include tetramethylolguanamine, tetramethoxymethylguanamine, a compound of tetramethylolguanamine in which 1 to 4 methylol groups are methoxymethylated, or a mixture thereof; tetramethoxyethylguanamine, tetraacyloxyguanamine, a compound of tetramethylolguanamine in which 1 to 4 methylol groups are acyloxymethylated, or a mixture thereof; and the like.

[0254] Examples of the glycoluril compound include tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, a compound in which 1 to 4 methylol groups of tetramethylol glycoluril are methoxymethylated or a mixture thereof, a compound in which 1 to 4 methylol groups of tetramethylol glycoluril are acyloxymethylated or a mixture thereof, etc. Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound in which 1 to 4 methylol groups of tetramethylol urea are methoxymethylated or a mixture thereof, tetramethoxyethyl urea, etc.

[0255] Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0256] Examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0257] 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.

[0258] When the resist composition of the present invention is a negative resist composition 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, per 100 parts by mass of the base polymer. The crosslinking agents may be used singly or in combination of two or more.

[0259] Examples of the other quenchers include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. Particularly preferred are the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A, particularly amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond, and compounds having a carbamate group described in Japanese Patent No. 3790649 A. Addition of such basic compounds can, for example, further suppress the diffusion rate of acid in the resist film or correct the shape.

[0260] Other quenchers include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids that are not fluorinated at the α-position, as described in JP-A-2008-158339. Sulfonic acids, imide acids, or methide acids that are fluorinated at the α-position are necessary for deprotecting the acid labile group of a carboxylic acid ester, and salt exchange with an onium salt that is not fluorinated at the α-position releases sulfonic acids or carboxylic acids that are not fluorinated at the α-position. Sulfonic acids and carboxylic acids that are not fluorinated at the α-position do not undergo deprotection reactions, and therefore function as quenchers.

[0261] Other examples of quenchers include the polymer-type quenchers described in JP 2008-239918 A. These quenchers enhance the rectangularity of the resist pattern by orienting on the surface of the resist film. Polymer-type quenchers also have the effect of preventing pattern film loss and rounding of the pattern top when a protective film for immersion lithography is applied.

[0262] When the resist composition of the present invention contains another quencher, the content thereof is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, relative to 100 parts by mass of the base polymer. The other quenchers may be used singly or in combination of two or more.

[0263] The water repellency improver improves the water repellency of the resist film surface and can be used in immersion lithography without a topcoat. Preferred examples of the water repellency improver include polymers containing fluorinated alkyl groups and polymers containing a specific 1,1,1,3,3,3-hexafluoro-2-propanol residue structure, with those exemplified in JP-A Nos. 2007-297590 and 2008-111103 being more preferred. The water repellency improver must be soluble in an alkaline developer or an organic solvent developer. The water repellency improver having the specific 1,1,1,3,3,3-hexafluoro-2-propanol residue described above has good solubility in the developer. As a water repellency improver, polymers containing repeating units containing an amino group or an amine salt are highly effective in preventing the evaporation of acid during PEB and preventing poor opening 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, relative to 100 parts by mass of the base polymer. The water repellency improver may be used alone or in combination of two or more.

[0264] 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 thereof is preferably 0 to 5 parts by mass per 100 parts by mass of the base polymer. The acetylene alcohols may be used alone or in combination of two or more.

[0265] [Pattern formation method] When the resist material of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied. For example, a pattern formation method can include a method comprising the steps of forming a resist film on a substrate using the resist material, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0266] 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 antireflective coating, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., to a coating thickness of 0.01 to 2 μm. This is then prebaked 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.

[0267] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, EB, EUV radiation with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When ultraviolet radiation, far ultraviolet radiation, EUV radiation, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation are used as the high-energy radiation, the exposure dose is preferably 1 to 200 mJ / cm, either directly or using a mask for forming a desired pattern. 2 approximately, more preferably 10 to 100 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 300 μC / cm 2 approximately, more preferably 0.5 to 200 μC / cm 2 The resist material of the present invention is particularly suitable for fine patterning using high-energy rays such as KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, γ-rays, and synchrotron radiation, and is particularly suitable for fine patterning using EB or EUV.

[0268] After 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.

[0269] After exposure or PEB, the exposed resist film is developed using a developer of an alkaline aqueous solution of 0.1 to 10% by weight, preferably 2 to 5% by weight, such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by a conventional method such as dipping, puddling, or spraying, to form the desired pattern. In the case of a positive resist material, the irradiated portion dissolves in the developer, while the unexposed portion remains insoluble, forming the desired positive pattern on the substrate. In the case of a negative resist material, the opposite occurs: the irradiated portion becomes insoluble in the developer, while the unexposed portion dissolves.

[0270] A negative pattern can also be obtained by organic solvent development using a positive resist material containing a base polymer containing an acid labile group. The developer used in this case includes 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, Examples of the organic solvent include methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0271] After the development is completed, the resist film is rinsed. A solvent that is miscible with the developer but does not dissolve the resist film is preferred as the rinse solution. Preferred examples of such solvents include 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.

[0272] Examples of the alcohol having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, Examples of such 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.

[0273] 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.

[0274] Examples of the alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Examples of the alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of the alkynes having 6 to 12 carbon atoms include hexyne, heptine, and octyne.

[0275] Examples of the aromatic solvent include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0276] 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.

[0277] The developed hole or trench pattern can also be shrunk using thermal flow, RELACS, or DSA. A shrink agent is applied to the hole pattern, and the diffusion of an acid catalyst from the resist film during baking causes crosslinking of the shrink agent on the surface of the resist film, resulting in adhesion of the shrink agent 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. Excess shrink agent is removed, and the hole pattern is shrunk. [Example]

[0278] The present invention will be specifically explained below by showing synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples.

[0279] [Synthesis Example 1-1] Synthesis of Quencher Q-1 (1) Synthesis of intermediate In-1 [ka]

[0280] A Grignard reagent was prepared from 100 g of 2-bromodibenzothiophene, 9.7 g of magnesium, and 500 g of THF under a nitrogen atmosphere. Dry ice and THF were placed in a separate container, and the Grignard reagent was added dropwise thereto, followed by aging for 2 hours. Subsequently, dilute hydrochloric acid was added dropwise, followed by the addition of 1 L of ethyl acetate, and the organic layer was separated. The organic layer was washed with ultrapure water and then concentrated under reduced pressure. Toluene was added to the residue and recrystallized. The resulting crystals were filtered and dried under reduced pressure, yielding 58 g of the desired intermediate In-1 (yield 67%).

[0281] (2) Synthesis of intermediate In-2 [ka]

[0282] 20 g of intermediate In-1, 70 g of methanol, and 0.4 g of concentrated sulfuric acid were mixed, and the resulting solution was refluxed for 24 hours. Triethylamine was then added to terminate the reaction. Toluene was added to the reaction solution, and the organic layer was washed with ultrapure water. After that, the solution was concentrated under reduced pressure, and n-hexane was added to the residue to recrystallize it. The resulting crystals were filtered and dried under reduced pressure, yielding 18 g of the desired intermediate In-2 (yield 87%).

[0283] (3) Synthesis of intermediate In-3 [ka]

[0284] 10 g of intermediate In-2, 20 g of diphenyliodonium triflate, 0.3 g of copper acetate, and 50 g of anisole were mixed, and the resulting solution was heated and stirred at 100°C for 2 hours under a nitrogen atmosphere. Diisopropyl ether was added to the reaction solution to precipitate crystals, which were then filtered to obtain crude crystals. The crude crystals were purified by recrystallization using dichloromethane / methyl isobutyl ketone, and the resulting crystals were filtered and dried under reduced pressure to obtain 15 g of the desired intermediate In-3 (yield 80%).

[0285] (4) Synthesis of intermediate In-4 [ka]

[0286] 13 g of intermediate In-3, 40 g of ion exchange resin (Organo Corporation, Amberlite IRA410J Cl), and 100 g of methanol were mixed, and the resulting solution was stirred at room temperature for 2 hours and then filtered. The filtrate was concentrated under reduced pressure, and n-hexane was added to the residue to recrystallize it. The precipitated crystals were filtered and dried under reduced pressure to obtain 9.4 g of the desired intermediate In-4 (yield 95%).

[0287] (5) Synthesis of quencher Q-1 [ka]

[0288] 3.5 g of anionic intermediate AIn-1 (synthesized with reference to Japanese Patent No. 5904180), 3.5 g of intermediate In-4, 20 g of methylene chloride, and 10 g of water were mixed, and the resulting solution was stirred at room temperature for 1 hour. The organic layer was then separated and washed with ultrapure water, and the organic solvent was removed by vacuum concentration. Diisopropyl ether was added to the residue and recrystallized. The resulting crystals were collected by filtration and dried under reduced pressure to obtain 5.8 g of the target quencher Q-1 (yield 89%).

[0289] [Synthesis Examples 1-2 to 1-21] Synthesis of Quenchers Q-2 to Q-21 Quenchers Q-2 to Q-21 were synthesized in the same manner as in Synthesis Example 1-1. The structures of quenchers Q-1 to Q-21 are shown below. [ka]

[0290] [ka]

[0291] [ka]

[0292] [ka]

[0293] [ka]

[0294] [Synthesis Example 2-2] Synthesis of base polymers (P-1 to P-5) 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 (P-1 to P-5) with the following compositions. The resulting base polymers were 1 Mw and Mw / Mn were confirmed by H-NMR and GPC (solvent: THF, standard: polystyrene). [ka]

[0295] [ka]

[0296] [Examples 1 to 25, Comparative Examples 1 to 4] Preparation and Evaluation of Resist Materials (1) Preparation of resist material Resist materials were prepared by filtering solutions containing the components dissolved according to the compositions shown in Tables 1 and 2 through a 0.2 μm filter. The resist materials of Examples 1 to 24 and Comparative Examples 1 to 3 were positive-working, while the resist materials of Example 25 and Comparative Example 4 were negative-working.

[0297] In Tables 1 and 2, the components are as follows: Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol) EL (Ethyl lactate)

[0298] Acid generator: PAG-1 to PAG-4 [ka]

[0299] Blend quencher: bQ-1, bQ-2 [ka]

[0300] Comparison quenchers: cQ-1 to cQ-3 [ka]

[0301] (2) EUV lithography evaluation Each resist material shown in Tables 1 and 2 was spin-coated onto a Si substrate with a 20 nm thick silicon-containing spin-on hard mask SHB-A940 (43% silicon by mass) manufactured by Shin-Etsu Chemical Co., Ltd., and pre-baked at 100 °C for 60 seconds using a hot plate to produce a 60 nm thick resist film. The resist film was then exposed to light using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, wafer dimensions 44 nm pitch, +20% bias hole pattern mask), subjected to PEB on a hot plate at the temperature shown in Tables 1 and 2 for 60 seconds, and developed for 30 seconds with a 2.38% by mass TMAH aqueous solution. In Examples 1 to 24 and Comparative Examples 1 to 3, a 22 nm hole pattern was obtained, and in Example 25 and Comparative Example 4, a 22 nm dot pattern was obtained. Using a critical dimension SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, the exposure dose when a hole or dot dimension of 22 nm was measured was used to determine the sensitivity. The dimensions of 50 holes or dots were also measured, and the CDU was calculated by multiplying the standard deviation (σ) by three (3σ). The results are shown in Tables 1 and 2.

[0302] [Table 1]

[0303] [Table 2]

[0304] The results shown in Tables 1 and 2 demonstrate that the resist material of the present invention has high sensitivity and improved CDU.

Claims

1. A sulfonium salt represented by the following formula (1): 【Chemistry 1】 [In the formula, p is an integer of 0 to 3, q ​​and r are 0, and s is 1 or 2, provided that 1≦r+s≦3. R 1 and R 2 are each independently a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a nitro group, or a cyano group. R 3 represents a halogen atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a nitro group, a cyano group, or —O—C(═O)—R 5 Or -O-R 5 is. R 4 represents a hydrocarbyloxy group in which the hydrocarbyl moiety is an alkyl group having 1 to 4 carbon atoms, or -O-R 4A and the hydrocarbyloxy group may be substituted with a fluorine atom. 4A is an acid labile group represented by any one of the following formulae (AL-1) to (AL-3). 【Chemistry 2】 (In the formula, the dashed lines represent bonds. R L1 and R L2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. c is an integer from 0 to 10. 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. L2 , R L3 and R L4 Any two of the above 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. R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms and may contain a heteroatom. L5 , R L6 and R L7 Any two of may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they are attached.) R 5 is a hydrocarbyl group having 1 to 10 carbon atoms. X 1 is a single bond or a carbonyl group. Xq - is an anion represented by any of the following formulas: 【Transformation 3】 【Chemistry 4】 ］

2. The sulfonium salt according to claim 1, represented by any one of the following formulas Q-1 to Q-21: 【Transformation 5】 【Transformation 6】 【Transformation 7】 【Transformation 8】 【Chemistry 9】

3. A resist material comprising a quencher comprising the sulfonium salt of claim 1.

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

5. 5. The resist material according to claim 4, wherein the base polymer contains a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2): 【Chemistry 10】 (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid labile group. R 13 is a fluorine atom, a trifluoromethyl group, a cyano group or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of the carbon atoms of which may be substituted with ether bonds or ester bonds. a is 1 or 2, and b is an integer from 0 to 4, provided that 1≦a+b≦5.

6. 6. The resist material according to claim 5, which is a chemically amplified positive resist material.

7. 5. The resist material according to claim 4, wherein the base polymer does not contain any acid labile groups.

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

9. 5. The resist material according to claim 4, wherein the base polymer comprises at least one repeating unit selected from the group consisting of repeating units represented by the following formulas (f1) to (f3): 【Chemistry 11】 (In the formula, R A are each independently a hydrogen atom or a methyl group. Z 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -O-Z 11 -, -C(=O)-O-Z 11 - or -C(=O)-NH-Z 11 - is. Z 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -O-C(=O)-. Z 31 represents an aliphatic hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, a urethane bond, a nitro group, a cyano group, a fluorine atom, an iodine atom, or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. Z 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 - is. Z 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom, or a hydroxy group. R 21 ~R 28 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 and R 24 and or R 26 and R 27 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. M - is a non-nucleophilic counterion.)

10. 4. The resist material according to claim 3, further comprising an acid generator that generates a strong acid.

11. 11. The resist material according to claim 10, wherein the acid generator generates a sulfonic acid, an imide acid, or a methide acid.

12. The resist material according to claim 3, further comprising an organic solvent.

13. The resist material according to claim 3, further comprising a surfactant.

14. 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 3 to 13; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

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

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