Resist material and pattern formation method

Abstract

To provide a resist material which exhibits high sensitivity and improved LWR and CDU regardless of whether it is positive or negative, and a pattern forming method using the same.SOLUTION: The resist material contains a base polymer and a quencher. The quencher contains a salt compound comprising: a cyclic ammonium cation represented by the following formula (A-1) or (A-2); and an anion derived from a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, or a fluorinated imide compound.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern rules is progressing rapidly. In particular, the expansion of the logic memory market due to the proliferation of smartphones is driving this miniaturization. As for the most advanced miniaturization technology, mass production of 10nm node devices is underway using double patterning in ArF immersion lithography, and preparations for mass production of 7nm node devices using the same double patterning method are underway for the next generation. For the next-generation 5nm node, extreme ultraviolet (EUV) lithography is being considered as a candidate.

[0003] While miniaturization is progressing in logic devices, flash memory is evolving into devices with stacked gates called 3D-NAND, and capacity is increasing as the number of stacks increases. As the number of stacks increases, the hard mask used to process it becomes thicker, and the photoresist film also becomes thicker. The resist film for logic devices is becoming thinner, while the resist film for 3D-NAND is becoming thicker.

[0004] As miniaturization progresses and approaches the diffraction limit of light, the contrast of light decreases. This decrease in light contrast leads to a reduction in the resolution of hole and trench patterns, as well as a decrease in the focus margin, in positive-type resist films. Thickening the resist film returns it to the thickness of resist films used in previous generations of devices, but it requires even greater dimensional uniformity (CDU), which cannot be met by previous photoresists. To prevent the decrease in resolution of resist patterns due to the decrease in light contrast caused by the reduction in size, or to improve CDU when thickening the resist film, attempts are being made to improve the dissolution contrast of the resist film.

[0005] For chemically amplified positive-type resist materials that undergo an acid-induced deprotection reaction by adding an acid generator and irradiating them with light or electron beam (EB), and for chemically amplified negative-type resist materials that undergo an acid-induced polarity change reaction or crosslinking reaction, the addition of a quencher to control the diffusion of acid into unexposed areas and improve contrast has been very effective. As a result, many amine quenchers have been proposed (Patent Documents 1 and 2).

[0006] Amine quenchers involving polarity changes catalyzed by acid have been proposed. Patent Document 3 proposes an amine quencher having an acid-unstable group. In this case, a carboxylic acid is generated by the deprotection reaction of a tertiary ester with a carbonyl group positioned on the nitrogen atom side using an acid, improving alkali solubility. However, in this case, the molecular weight on the nitrogen atom side cannot be increased, resulting in low acid diffusion control ability and only a slight improvement in contrast. Patent Document 4 proposes a quencher in which an amino group is generated by the deprotection reaction of a tert-butoxycarbonyl group using an acid. This is a mechanism in which the quencher is generated by exposure, which has the opposite effect of increasing contrast. Contrast is improved by a mechanism in which the quencher disappears or the quenching ability decreases due to exposure or acid. Patent Document 5 proposes a quencher in which an amine compound forms a ring and becomes a lactam structure when exposed to acid. The acid activity changes as a strongly basic amine compound changes into a weakly basic lactam compound, improving contrast.

[0007] Acid-unstable groups used in (meth)acrylate polymers for ArF resist materials undergo deprotection reactions by using a photoacid generator that produces sulfonic acid with a fluorine atom substituted at the α-position. However, deprotection reactions do not proceed with acid generators that produce sulfonic acid or carboxylic acid without a fluorine atom substituted at the α-position. When a sulfonium salt or iodonium salt that produces sulfonic acid with a fluorine atom substituted at the α-position is mixed with a sulfonium salt or iodonium salt that produces sulfonic acid without a fluorine atom substituted at the α-position, the sulfonium salt or iodonium salt that produces sulfonic acid without a fluorine atom substituted at the α-position undergoes ion exchange with the sulfonic acid with a fluorine atom substituted at the α-position. Since the sulfonic acid with a fluorine atom substituted at the α-position generated by light reverts back to the sulfonium salt or iodonium salt through ion exchange, the sulfonium salt or iodonium salt of sulfonic acid or carboxylic acid without a fluorine atom substituted 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 6).

[0008] Sulfonium salt type quenchers and iodonium salt type quenchers are photodegradable, similar to photoacid generators. This means that the amount of quencher decreases in the exposed areas. Since acid is generated in the exposed areas, a decrease in the amount of quencher leads to a relative increase in acid concentration, thereby improving contrast. However, because acid diffusion in the exposed areas cannot be suppressed, controlling acid diffusion becomes difficult.

[0009] Sulfonium salt type quenchers and iodonium salt type quenchers absorb light at a wavelength of 193 nm. Therefore, when used in combination with sulfonium salt type or iodonium salt type acid generators, the transmittance of the resist film to this light decreases. As a result, the cross-sectional shape of the pattern after development becomes tapered, especially in resist films with a thickness of 100 nm or more. For resist films with a thickness of 100 nm or more, especially 150 nm or more, a highly transparent quencher is required.

[0010] Lowering the post-exposure bake (PEB) temperature is effective in suppressing acid diffusion. However, this reduces dissolution contrast, leading to a degradation of resolution and low-level roughness (LWR). A new concept of resist material is needed that suppresses acid diffusion while maintaining high contrast. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2001-194776 [Patent Document 2] Japanese Patent Publication No. 2002-226470 [Patent Document 3] Japanese Patent Publication No. 2002-363148 [Patent Document 4] Japanese Patent Publication No. 2001-166476 [Patent Document 5] Japanese Patent Publication No. 2012-137729 [Patent Document 6] International Publication No. 2008 / 066011 [Overview of the project] [Problems that the invention aims to solve]

[0012] In resist materials, there is a need for the development of a quencher that can improve the LWR of line patterns and the CDU of hole patterns, while also increasing sensitivity. This requires further reducing the diffusion distance of the acid while simultaneously improving contrast, thus improving both conflicting properties.

[0013] This invention has been made in view of the above circumstances, and aims to provide a resist material that is highly sensitive and has improved LWR and CDU, whether it is positive or negative type, and a pattern formation method using the same. [Means for solving the problem]

[0014] As a result of diligent research to achieve the above objective, the inventors have discovered that by using a salt consisting of a cyclic ammonium cation having a tertiary ester structure and an anion derived from a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, or a fluorinated imide compound as a quencher, it is possible to obtain a resist material with improved LWR and CDU, high contrast, excellent resolution, and a wide process margin, thus completing the present invention.

[0015] In other words, the present invention provides the following resist material and pattern formation method. 1. A resist material comprising a base polymer and a quencher, A resist material wherein the quencher comprises a salt compound consisting of a cyclic ammonium cation represented by the following formula (A-1) or (A-2) and an anion derived from a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, or a fluorinated imide compound. [ka] (In the formula, m is an integer between 1 and 6.) R 1 When m is 1, it is a hydrocarbyl group having 1 to 30 carbon atoms; when m is 2, it is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms; and when m is an integer from 3 to 6, it is an m-valent hydrocarbon group having 1 to 30 carbon atoms. The hydrocarbyl group, hydrocarbylene group and m-valent hydrocarbon group may include at least one selected from a hydroxyl group, a thiol group, an ester bond, a thioester bond, a thionoester bond, an ether bond, a sulfide bond, a halogen atom other than iodine and bromine atoms, a nitro group, an amino group, an amide bond, a sulfonyl group, a sulfonic acid ester bond, a sultone ring, a lactam ring, and a carbonate bond. R 2 and R 3 Each of these is independently a saturated hydrocarbyl group having 1 to 6 carbon atoms, and R 2 and R 3may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. R 4 and R 6 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxycarbonyl group having 2 to 12 carbon atoms. R 5 is an aliphatic hydrocarbyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may be substituted with a halogen atom or a trifluoromethyl group. Ring R is an alicyclic group having 2 to 10 carbon atoms formed together with the nitrogen atom in the formula.) 2. A resist material of 1, wherein an anion derived from the fluorinated 1,3-diketone compound, the fluorinated β-ketoester compound, or the fluorinated imide compound is represented by the following formula (B). [Chemical formula] (In the formula, R 7 and R 8 are each independently a hydrocarbyl group having 1 to 16 carbon atoms, a fluorinated hydrocarbyl group having 1 to 16 carbon atoms, a hydrocarbyloxy group having 1 to 16 carbon atoms, or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, provided that at least one of R 7 and R 8 is a fluorinated hydrocarbyl group having 1 to 16 carbon atoms or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, and a part or all of the hydrogen atoms thereof may be substituted with at least one selected from halogen atoms other than cyano group, nitro group, hydroxy group, and fluorine atom, and a part of these -CH2- may be substituted with at least one selected from ether bond, ester bond, and thioether bond. X is -C(H)= or -N=. ) 3. The resist material of 1 or 2 further comprising an acid generator that generates sulfonic acid, imidic acid, or methidic acid. 4. The resist material of any one of 1 to 3 further comprising an organic solvent. 5. A resist material according to any of 1 to 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 Each of these is independently either a hydrogen atom or a methyl group. Y 1 This is a linking group having 1 to 12 carbon atoms, containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. Y 2 These are single bonds or ester bonds. Y 3 These are single bonds, ether bonds, or ester bonds. R 11 and R 12 These are, independently, acid-unstable groups. R 13 This is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 This is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and some of its -CH2- may be substituted with an ether bond or an ester bond. a is either 1 or 2. b is an integer between 0 and 4, where 1 ≤ a + b ≤ 5. 6. A chemically amplified positive-type resist material, which is the resist material of 5. 7. A resist material according to any of 1 to 4, wherein the base polymer does not contain acid-unstable groups. 8. A chemically amplified negative resist material, which is the resist material of 7. 9. Furthermore, any of the resist materials 1-8 containing a surfactant. 10. A resist material according to any of 1 to 9, wherein the base polymer contains repeating units represented by any of the following formulas (f1) to (f3). [ka] (In the formula, R AEach of these is independently either a hydrogen atom or a methyl group. Z 1 This refers to 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 - is Z 11 This is an aliphatic hydrocarbylene group, phenylene group, naphthylene group having 1 to 6 carbon atoms, 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 hydroxyl group. Z 2 This is a single bond, -Z 21 -C(=O)-O-, -Z 21 -O- or -Z 21 -OC(=O)- Z 21 This is a saturated hydrocarbylene group having 1 to 12 carbon atoms, and may contain a carbonyl group, an ester bond, or an ether bond. Z 3 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, phenylene groups substituted with trifluoromethyl groups, -OZ 31 -, -C(=O)-OZ 31 -or -C(=O)-NH-Z 31 - is Z 31 This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. R 21 ~R 28 Each of these is independently a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom. 23 and R 24 or R 26 and R 27 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. R HFThis is either a hydrogen atom or a trifluoromethyl group. M - (It is a non-nucleophilic counterion.) A pattern forming method comprising the steps of: forming a resist film on a substrate using any of the resist materials from 11.1 to 10; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer. 12. Pattern formation method 11, wherein the high-energy ray is an i-line with a wavelength of 365 nm, an ArF excimer laser light with a wavelength of 193 nm, a KrF excimer laser light with a wavelength of 248 nm, an EB, or an EUV with a wavelength of 3 to 15 nm. [Effects of the Invention]

[0016] The aforementioned cyclic ammonium salt compound is a quencher that suppresses acid diffusion due to the presence of a nitrogen atom. Furthermore, because it has an acid-degradable tertiary ester structure, the exposed area decomposes with acid and transforms into a cyclic ammonium salt compound with a smaller molecular weight. This improves the acid activity in the exposed area and enhances contrast. Moreover, when the salt is combined with an anion selected from fluorinated 1,3-diketone compounds, fluorinated β-ketoester compounds, or fluorinated imide compounds, the ammonium salt is uniformly dispersed within the resist film due to the electrical repulsion of fluorine. This makes it possible to improve high contrast sensitivity with low acid diffusion, and to improve LWR and CDU. As a result, it is possible to construct a resist material with high sensitivity, low LWR, and low CDU. [Modes for carrying out the invention]

[0017] [Resist material] The resist material of the present invention comprises a base polymer and a quencher containing a cyclic ammonium salt compound having a tertiary ester structure.

[0018] [Cyclic ammonium salt compounds having a tertiary ester structure] The cyclic ammonium salt compound having a tertiary ester structure comprises a salt compound consisting of a cyclic ammonium cation represented by the following formula (A-1) or (A-2) and an anion derived from a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, or a fluorinated imide compound. [ka]

[0019] In formulas (A-1) and (A-2), m is an integer from 1 to 6, but is preferably an integer from 1 to 4, more preferably 1 or 2, and even more preferably 1.

[0020] In equations (A-1) and (A-2), R 1 When m is 1, it is a hydrocarbyl group having 1 to 30 carbon atoms; when m is 2, it is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms; and when m is an integer from 3 to 6, it is an m-valent hydrocarbon group having 1 to 30 carbon atoms. The hydrocarbyl group, hydrocarbylene group and m-valent hydrocarbon group may include at least one selected from a hydroxyl group, a thiol group, an ester bond, a thioester bond, a thionoester bond, an ether bond, a sulfide bond, a halogen atom other than iodine and bromine atoms, a nitro group, an amino group, an amide bond, a sulfonyl group, a sulfonic acid ester bond, a sultone ring, a lactam ring, and a carbonate bond.

[0021] The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 30 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, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl; cyclopropyl, cyclopentyl, cyclohexyl, norbornyl, adamantyl, and cyclopentahydrophenane. Examples include cyclic saturated hydrocarbyl groups with 3 to 30 carbon atoms, such as the threne group; alkenyl groups with 2 to 30 carbon atoms, such as vinyl, 1-methylvinyl, 1-propenyl, 2-propenyl, butenyl, pentenyl, and hexenyl groups; alkynyl groups with 2 to 20 carbon atoms, such as ethynyl, propynyl, and butynyl groups; cyclic unsaturated aliphatic hydrocarbyl groups with 3 to 30 carbon atoms, such as cyclopentenyl, cyclohexenyl, and norbornenyl groups; aryl groups with 6 to 30 carbon atoms, such as phenyl, naphthyl, phenanthryl, anthryl, and fluorenyl groups; aralkyl groups with 7 to 30 carbon atoms, such as benzyl and phenethyl groups; and groups obtained by combining these.

[0022] The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is a group obtained by removing one more hydrogen atom from the specific example of the hydrocarbyl group described above. The m-valent hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is a group obtained by removing (m-1) more hydrogen atoms from the specific example of the hydrocarbyl group described above.

[0023] In formula (A-1), R 2 and R 3 Each of these is independently a saturated hydrocarbyl group having 1 to 6 carbon atoms, and R 2 and R 3These groups may bond with each other to form a ring with the carbon atom to which they are bonded. The saturated hydrocarbyl group may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl; and cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0024] In equations (A-1) and (A-2), R 4 and R 6 Each of these is independently a hydrogen atom, a C1-C4 alkyl group, or a C2-C12 alkoxycarbonyl group. Examples of the C1-C4 alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, and tert-butyl group. Examples of the C2-C12 alkoxycarbonyl group include methoxycarbonyl group, ethoxycarbonyl group, n-propyloxycarbonyl group, isopropyloxycarbonyl group, n-butyloxycarbonyl group, isobutyloxycarbonyl group, sec-butyloxycarbonyl group, tert-butyloxycarbonyl group, n-pentyloxycarbonyl group, sec-pentyloxycarbonyl group, tert-pentyloxycarbonyl group, neopentyloxycarbonyl group, n- Examples include hexyloxycarbonyl group, n-heptyloxycarbonyl group, n-octyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, n-nonyloxycarbonyl group, n-decyloxycarbonyl group, n-undecyloxycarbonyl group, n-dodecyloxycarbonyl group, n-tridecyloxycarbonyl group, n-pentadecyloxycarbonyl group, vinyloxycarbonyl group, 1-propenyloxycarbonyl group, and 2-propenyloxycarbonyl group.

[0025] In formula (A-2), R 5 This is an aliphatic hydrocarbyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may be substituted with a halogen atom or a trifluoromethyl group. The aliphatic hydrocarbyl group having 1 to 6 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl; cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; alkenyl groups such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl; alkynyl groups such as ethynyl, propynyl, and butynyl; and cyclic unsaturated hydrocarbyl groups such as cyclohexenyl. Examples of the aryl group having 6 to 12 carbon atoms include phenyl, tolyl, xylyl, 1-naphthyl, and 2-naphthyl.

[0026] Of these, R 2 and R 3 As such, alkyl groups having 1 to 3 carbon atoms are preferred. 4 and R 6 Preferably, the elements are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxycarbonyl group having 2 to 6 carbon atoms. 5 Preferably, the group is an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, or an alkynyl group having 2 to 4 carbon atoms.

[0027] In formulas (A-1) and (A-2), ring R is an alicyclic group having 2 to 10 carbon atoms, which is composed of the nitrogen atom in the formula. Examples of such alicyclic groups include groups having a structure in which one carbon atom of a cyclic hydrocarbon such as cyclopropane, cyclopentane, cyclohexane, norbornane, and adamantane is replaced by a nitrogen atom.

[0028] Examples of cations represented by formula (A-1) include, but are not limited to, those listed below. [ka]

[0029] [ka]

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[0073] [ka]

[0074] Examples of cations represented by formula (A-2) include, but are not limited to, those listed below. [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

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[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] The cyclic ammonium salt compound includes an anion derived from a fluorinated 1,3-diketone compound anion, a fluorinated β-ketoester compound anion, or a fluorinated imide compound.

[0118] The anion is preferably one represented by the following formula (B). [ka]

[0119] In formula (B), R 7 and R 8 These are, independently, a C1-C16 hydrocarbyl group, a C1-C16 fluorinated hydrocarbyl group, a C1-C16 hydrocarbyloxy group, and a C1-C16 fluorinated hydrocarbyloxy group, but R 7 and R 8 At least one of these is a fluorinated hydrocarbyl group having 1 to 16 carbon atoms or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, and some or all of these hydrogen atoms may be substituted with at least one selected from a cyano group, a nitro group, a hydroxyl group, and a halogen atom other than a fluorine atom, and some of these -CH2- may be substituted with at least one selected from an ether bond, an ester bond, and a thioether bond.

[0120] R 7 and R8The hydrocarbyl group and hydrocarbyloxy group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups with 1 to 16 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, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and hexadecyl. Groups; cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, cyclopropylmethyl group, cyclopropylethyl group, cyclobutylmethyl group, cyclobutylethyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclohexylmethyl group, cyclohexylethyl group, methylcyclopropyl group, methylcyclobutyl group, methylcyclopentyl group, methylcyclohexyl group, ethylcyclopropyl group, Cyclic saturated hydrocarbyl groups with 3 to 16 carbon atoms, such as ethylcyclobutyl group, ethylcyclopentyl group, and ethylcyclohexyl group; alkenyl groups with 2 to 16 carbon atoms, such as vinyl group, 1-propenyl group, 2-propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, and hexadecenyl group; ethinyl group, propynyl group, butynyl group, pentynyl group Alkynyl groups having 2 to 16 carbon atoms, such as hexynyl, heptynyl, octinyl, noninyl, desinyl, undecynyl, dodecynyl, tridecynyl, tetradecynyl, pentadecynyl, and hexadesinyl groups; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 16 carbon atoms, such as cyclopentenyl, cyclohexenyl, methylcyclopentenyl, methylcyclohexenyl, ethylcyclopentenyl, ethylcyclohexenyl, and norbornenyl groups;Examples include aryl groups with 6 to 16 carbon atoms, such as phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group, methylnaphthyl group, ethylnaphthyl group, n-propylnaphthyl group, isopropylnaphthyl group, n-butylnaphthyl group, isobutylnaphthyl group, sec-butylnaphthyl group, and tert-butylnaphthyl group; aralkyl groups with 7 to 16 carbon atoms, such as benzyl group, phenethyl group, phenylpropyl group, phenylbutyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 9-fluorenylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, and 9-fluorenylethyl group; and groups obtained by combining these.

[0121] R 7 and R 8 The fluorinated hydrocarbyl group and the fluorinated hydrocarbyloxy group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. A specific example is R 7 and R 8Examples of groups in which at least one hydrogen atom of the group exemplified as the hydrocarbyl portion of the hydrocarbyl group and hydrocarbyloxy group represented by is substituted with a fluorine atom include monofluoromethyl group, difluoromethyl group, trifluoromethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2,2-pentafluoroethyl group, 1,1,1,3,3,3-hexafluoro-2-propyl group, 1,1,2,2,3,3,3-heptafluoropropyl group, 1,1,2,2,3,3,4,4,4-nonafluorobutyl group, 2-fluorophenyl group, 3-fluorophenyl group, 4-fluorophenyl group Examples include ruolophenyl group, 2,4-difluorophenyl group, 2,3-difluorophenyl group, 3,4-difluorophenyl group, 3,5-difluorophenyl group, 2,4,5-trifluorophenyl group, 2,3,4-trifluorophenyl group, 2,3,4,5-tetrafluorophenyl group, 2,3,5,6-tetrafluorophenyl group, 2,3,4,5,6-pentafluorophenyl group, pentafluoromethylphenyl group, 2-trifluoromethylphenyl group, 3-trifluoromethylphenyl group, 4-trifluoromethylphenyl group, and 2,4,5-trifluorophenyl group.

[0122] In equation (B), X is either -C(H) = or -N =.

[0123] Examples of anions derived from the fluorinated 1,3-diketone compound, fluorinated β-ketoester compound, and fluorinated imide compound include, but are not limited to, those listed below. [ka]

[0124] [ka]

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] The cyclic ammonium salt compound can be synthesized, for example, by a neutralization reaction between a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, or a fluorinated imide compound, and an amine compound having a tertiary ester group, which is synthesized by the esterification reaction of a carboxylic acid chloride compound and an amine compound having a tertiary hydroxyl group. The neutralization reaction is preferably carried out in amounts such that the molar ratio of the amine compound to the fluorinated 1,3-diketone compound, fluorinated β-ketoester compound, or fluorinated imide compound is 1:1, but one of them may be in excess.

[0129] The cyclic ammonium salt compound functions as a quencher that controls acid diffusion in the resist material. Because the cyclic ammonium salt compound has an acid-degradable tertiary ester group, it decomposes with acid, reducing its molecular weight. A decrease in the molecular weight of the amino group-containing compound reduces its acid diffusion ability and improves its acid reactivity. The reduction in the molecular weight of the cyclic ammonium salt compound due to acid occurs in the exposed region. High acid diffusion control is maintained in the unexposed region, while acid diffusion improves in the exposed region. This increases the difference in reactivity between the unexposed and exposed areas, thereby improving the reaction contrast. This makes it possible to improve contrast while suppressing acid diffusion.

[0130] Furthermore, because the anion contains a fluorine atom, the quenchers do not aggregate due to the electrical repulsion of the fluorine atom, resulting in uniform acid diffusion at the nanometer level. This improves the LWR and CDU of the resist pattern after development.

[0131] The cyclic ammonium salt compound is highly lipophilic in the unexposed areas before acid decomposition, making it difficult to dissolve in alkaline developers. After acid decomposition, it decomposes into a cyclic ammonium salt compound with a small molecular weight, a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, or a fluorinated imide compound, improving its alkali solubility. Therefore, the cyclic ammonium salt compound is particularly effective in alkaline development, suppressing film thinning of the pattern in the unexposed areas and preventing scum formation at the bottom of the pattern in the exposed areas. In particular, when the resist film thickness is 100 nm or more, the effect of preventing scum formation at the bottom of the pattern in the exposed areas is high.

[0132] In the resist material of the present invention, the content of the cyclic ammonium salt compound is preferably 0.001 to 50 parts by mass, and more preferably 0.01 to 40 parts by mass, relative to 100 parts by mass of the base polymer described later, from the viewpoint of sensitivity and acid diffusion suppression effect. The cyclic ammonium salt compound may be used alone or in combination of two or more.

[0133] [Base polymer] The base polymer contained in the resist material of the present invention, in the case of a positive-type resist material, contains repeating units containing acid-unstable groups. The repeating units containing acid-unstable groups are preferably those represented by the following formula (a1) (hereinafter also referred to as repeating unit a1) or the following formula (a2) (hereinafter also referred to as repeating unit a2). [ka]

[0134] In equations (a1) and (a2), R A Each of these is independently either a hydrogen atom or a methyl group. 1 This is a linking group having 1 to 12 carbon atoms, containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. 2 These are single bonds or ester bonds. 3These are single bonds, ether bonds, or ester bonds. 11 and R 12 These are, independently, acid-unstable groups. Furthermore, if the base polymer contains both repeating unit a1 and repeating unit a2, R 11 and R 12 These may be identical or different from one another. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 14 a is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and some of its -CH2- may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer from 0 to 4, where 1 ≤ a + b ≤ 5.

[0135] Examples of monomers that give repeating unit a1 are listed below, but are not limited to these. Note that in the following formula, R A and R 11 This is the same as described above. [ka]

[0136] Examples of monomers that give repeating units a2 are listed below, but are not limited to these. Note that in the following formula, R A and R 12 This is the same as described above. [ka]

[0137] In equations (a1) and (a2), R 11 and R 12 Examples of acid-unstable groups represented by include those described in Japanese Patent Publication No. 2013-80033 and Japanese Patent Publication No. 2013-83821.

[0138] Typically, the acid-unstable groups mentioned above are those represented by the following formulas (AL-1) to (AL-3). [Chemical formula] (In the formula, the dashed line represents a bond.)

[0139] In formulas (AL-1) and (AL-2), R L1 and R L2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms, and may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 40 carbon atoms is preferred, and a saturated hydrocarbyl group having 1 to 20 carbon atoms is more preferred.

[0140] In formula (AL-1), c is an integer from 0 to 10, and an integer from 1 to 5 is preferred.

[0141] 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 an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms is preferred. Also, any two of R L2 , R L3 and R L4 may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded or a carbon atom and an oxygen atom. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0142] In formula (AL-3), R L5 , R L6 and R L7is, independently of each other, a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atom, sulfur atom, nitrogen atom, fluorine atom, etc. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms is preferred. Also, R L5 、R L6 and R L7 Any two of them may combine with each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they are attached. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0143] The base polymer may contain a repeating unit b containing a phenolic hydroxy group as an adhesion group. Examples of the monomer that gives the repeating unit b include, but are not limited to, the following. In the following formula, R A is the same as described above.

Chemical formula

[0144]

Chemical formula

[0145]

Chemical formula

[0146] The base polymer may contain a repeating unit c containing a hydroxy group other than a phenolic hydroxy group, a lactone ring, a sultone ring, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonyl group, a sulfonyl group, a cyano group or a carboxy group as another adhesion group. Examples of the monomer that gives the repeating unit c include, but are not limited to, the following. In the following formula, R A is the same as described above.

Chemical formula

[0147]

change

[0148]

change

[0149]

change

[0150]

change

[0151]

change

[0152]

change

[0153]

change

[0154]

change

[0155]

change

[0156] The base polymer may contain repeating units d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or derivatives thereof. Examples of monomers that give repeating units d are, but are not limited to, those listed below. [ka]

[0157] The base polymer may contain repeating units e derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindan, vinylpyridine, or vinylcarbazole.

[0158] The base polymer may contain repeating units f derived from an onium salt containing polymerizable unsaturated bonds. Preferred repeating units f include the repeating unit represented by the following formula (f1) (hereinafter also referred to as repeating unit f1), the repeating unit represented by the following formula (f2) (hereinafter also referred to as repeating unit f2), and the repeating unit represented by the following formula (f3) (hereinafter also referred to as repeating unit f3). Repeating units f1 to f3 may be used individually or in combination of two or more types. [ka]

[0159] In formulas (f1) to (f3), R A Each of these is independently either a hydrogen atom or a methyl group. 1 This refers to 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 - is Z 11This is an aliphatic hydrocarbylene group, phenylene group, naphthylene group having 1 to 6 carbon atoms, 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 hydroxyl group. 2 This is a single bond, -Z 21 -C(=O)-O-, -Z 21 -O- or -Z 21 -OC(=O)- Z 21 This is a saturated hydrocarbylene group having 1 to 12 carbon atoms, and may contain a carbonyl group, an ester bond, or an ether bond. 3 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, phenylene groups substituted with trifluoromethyl groups, -OZ 31 -, -C(=O)-OZ 31 -or -C(=O)-NH-Z 31 - is Z 31 This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 11 and Z 31 The aliphatic hydrocarbylene group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. 21 The saturated hydrocarbylene group represented by can be linear, branched, or cyclic.

[0160] In formulas (f1) to (f3), R 21 ~R 28 Each of these is a hydrocarbyl group having 1 to 20 carbon atoms, which may independently contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formulas (1-1) and (1-2) described later. 101 ~R 105Examples similar to those exemplified in the description can be given. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, mercapto groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0161] Also, R 23 and R 24 or R 26 and R 27 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is defined as R in the explanation of formula (1-1) described later. 101 and R 102 Examples of rings that can be formed when these elements combine with the sulfur atom to which they are bonded are similar to those exemplified.

[0162] In formula (f2), R HF This is either a hydrogen atom or a trifluoromethyl group.

[0163] In formula (f1), M -This is a non-nucleophilic counterion. Examples of the aforementioned non-nucleophilic counterions include halide ions such as chloride ions and bromide ions; fluoroalkyl sulfonate ions such as triflate ions, 1,1,1-trifluoroethanesulfonate ions, and nonafluorobutanesulfonate ions; aryl sulfonate ions such as tosylate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, and 1,2,3,4,5-pentafluorobenzenesulfonate ions; alkyl sulfonate ions such as mesylate ions and butanesulfonate ions; imide ions such as bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, and bis(perfluorobutylsulfonyl)imide ions; and methide ions such as tris(trifluoromethylsulfonyl)methide ions and tris(perfluoroethylsulfonyl)methide ions.

[0164] Other examples of the aforementioned non-nucleophilic counterions include a sulfonate ion in which the α-position is substituted with a fluorine atom, represented by the following formula (f1-1), and a sulfonate ion in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group, represented by the following formula (f1-2). [ka]

[0165] In formula (f1-1), R 31 R 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. A specific example is R in formula (1A') described later. 111 Examples of hydrocarbyl groups represented by the symbol shown are similar to those exemplified.

[0166] In formula (f1-2), R 32R is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and the hydrocarbyl group and hydrocarbylcarbonyl group may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl portion of the hydrocarbyl group and hydrocarbylcarbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (1A') described later. 111 Examples of hydrocarbyl groups represented by the symbol shown are similar to those exemplified.

[0167] Examples of monomer cations that give repeating units f1 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0168] Examples of monomer cations that give repeating units f2 or f3 include those similar to those exemplified as cations of sulfonium salts represented by formula (1-1) described later.

[0169] Examples of monomer anions that give the repeating unit f2 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0170] [ka]

[0171] Examples of monomer anions that give the repeating unit f3 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0172] [Chemical formula]

[0173] By bonding an acid generator to the polymer main chain, acid diffusion can be reduced, and a decrease in resolution due to blurring of acid diffusion can be prevented. In addition, by uniformly dispersing the acid generator, LWR and CDU are improved. When using a base polymer containing a repeating unit f (that is, a polymer-bound acid generator), the blending of the additive acid generator described later can be omitted.

[0174] The base polymer for the positive resist material must have a repeating unit a1 or a2 containing an acid-labile group. In this case, the content ratios of the repeating units a1, a2, b, c, d, e, and f are preferably 0≦a1<1.0, 0≦a2<1.0, 0<a1+a2<1.0, 0≦b≦0.9, 0≦c≦0.9, 0≦d≦0.8, 0≦e≦0.8, and 0≦f≦0.5, more preferably 0≦a1≦0.9, 0≦a2≦0.9, 0.1≦a1+a2≦0.9, 0≦b≦0.8, 0≦c≦0.8, 0≦d≦0.7, 0≦e≦0.7, and 0≦f≦0.4, and even more preferably 0≦a1≦0.8, 0≦a2≦0.8, 0.1≦a1+a2≦0.8, 0≦b≦0.75, 0≦c≦0.75, 0≦d≦0.6, 0≦e≦0.6, and 0≦f≦0.3. When the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Also, a1 + a2 + b + c + d + e + f = 1.0.

[0175] On the one hand, for the base polymer for a negative resist material, an acid-labile group is not necessarily required. Examples of such base polymers include those containing repeating unit b and optionally further containing repeating units c, d, e, and / or f. The content ratios of these repeating units are preferably 0 < b ≤ 1.0, 0 ≤ c ≤ 0.9, 0 ≤ d ≤ 0.8, 0 ≤ e ≤ 0.8, and 0 ≤ f ≤ 0.5, more preferably 0.2 ≤ b ≤ 1.0, 0 ≤ c ≤ 0.8, 0 ≤ d ≤ 0.7, 0 ≤ e ≤ 0.7, and 0 ≤ f ≤ 0.4, and still more preferably 0.3 ≤ b ≤ 1.0, 0 ≤ c ≤ 0.75, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.6, and 0 ≤ f ≤ 0.3. When repeating unit f is at least one selected from repeating units f1 to f3, f = f1 + f2 + f3. Also, b + c + d + e + f = 1.0.

[0176] To synthesize the base polymer, for example, monomers that provide the aforementioned repeating units may be heated in an organic solvent with a radical polymerization initiator added to perform polymerization.

[0177] Examples of the organic solvent used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, etc. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, etc. The temperature during polymerization is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0178] When copolymerizing a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid such as an ethoxyethoxy group before polymerization and then deprotected with a weak acid and water after polymerization, or it may be substituted with an acetyl group, a formyl group, a pivaloyl group, etc. and then subjected to alkaline hydrolysis after polymerization.

[0179] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and the acetoxy group may be deprotected by alkaline hydrolysis after polymerization to obtain hydroxystyrene or hydroxyvinylnaphthalene.

[0180] Ammonia water, triethylamine, etc., can be used as the base during alkaline hydrolysis. 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.

[0181] The base polymer has a polystyrene-based weight-average molecular weight (Mw) of 1,000 to 500,000, more preferably 2,000 to 30,000, determined by gel permeation chromatography (GPC) using THF as a solvent. When Mw is within this range, the heat resistance and solubility in alkaline developers of the resist film are good.

[0182] Furthermore, if the molecular weight distribution (Mw / Mn) of the base polymer is broad, low molecular weight and high molecular weight polymers may be present, which may result in the appearance of foreign matter on the pattern or deterioration of the pattern shape after exposure. As the pattern rules become finer, the influence of Mw and Mw / Mn tends to increase. Therefore, in order to obtain a resist material suitable for fine pattern dimensions, it is preferable that the Mw / Mn of the base polymer be narrowly dispersed, between 1.0 and 2.0, and particularly between 1.0 and 1.5.

[0183] The base polymer may contain two or more polymers with different composition ratios, Mw, and Mw / Mn.

[0184] [Acid Generator] The resist material of the present invention may contain an acid generator that generates a strong acid (hereinafter also referred to as an additive-type acid generator). Here, a strong acid means a compound having sufficient acidity to cause a deprotection reaction of acid-unstable groups of the base polymer in the case of a chemically amplified positive-type resist material, and a compound having sufficient acidity to cause a polarity change reaction or crosslinking reaction by an acid in the case of a chemically amplified negative-type resist material. By including such an acid generator, the aforementioned cyclic ammonium salt compound functions as a quencher, and the resist material of the present invention can function as a chemically amplified positive-type resist material or a chemically amplified negative-type resist material.

[0185] Examples of the acid-generating agent include compounds that generate acid in response to active light or radiation (photoacid generators). Any compound that generates acid upon irradiation with high-energy rays can be used as the photoacid generator, but those that generate sulfonic acid, imido acid, or methidoic acid are preferred. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc. Specific examples of photoacid generators are those described in paragraphs

[0122] to

[0142] of Japanese Patent Publication No. 2008-111103.

[0186] Furthermore, sulfonium salts represented by the following formula (1-1) and iodonium salts represented by the following formula (1-2) can also be suitably used as photoacid generators. [ka]

[0187] In equations (1-1) and (1-2), R 101 ~R 105 Each of these is independently a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom.

[0188] Examples of the halogen atoms mentioned above include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0189] R 101 ~R 105 The hydrocarbyl group, represented by , having 1 to 20 carbon atoms, may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups 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 eicosyl; C3-C20 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; C2-C20 alkenyl groups such as vinyl, propenyl, butenyl, and hexenyl; and ethynyl groups. Examples include alkynyl groups with 2 to 20 carbon atoms, such as propynyl and butynyl groups; cyclic unsaturated aliphatic hydrocarbyl groups with 3 to 20 carbon atoms, such as cyclohexenyl and norbornenyl groups; aryl groups with 6 to 20 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, and tert-butylnaphthyl groups; aralkyl groups with 7 to 20 carbon atoms, such as benzyl and phenethyl groups; and groups obtained by combining these.

[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, sulfur atom, nitrogen atom, or 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, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl 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 sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0191] Also, R 101 and R 102 These may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is preferably structured as shown below. [ka] (In the formula, the dashed line represents R 103 (This is a combination of the two.)

[0192] Examples of cations of the sulfonium salt represented by formula (1-1) include, but are not limited to, those listed below. [ka]

[0193] [ka]

[0194] [ka]

[0195] [ka]

[0196]

change

[0197]

change

[0198]

change

[0199]

change

[0200]

change

[0201]

change

[0202]

change

[0203]

change

[0204]

change

[0205]

change

[0206]

change

[0207] [ka]

[0208] [ka]

[0209] [ka]

[0210] [ka]

[0211] The cations of the iodonium salt represented by formula (1-2) include, but are not limited to, those listed below. [ka]

[0212] [ka]

[0213] In equations (1-1) and (1-2), Xa - This is an anion selected from the following formulas (1A) to (1D). [ka]

[0214] In formula (1A), R fa R 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. A specific example is R in formula (1A') described later. 111Examples of hydrocarbyl groups represented by the symbol shown are similar to those exemplified.

[0215] The anion represented by formula (1A) is preferably the one represented by formula (1A') below. [ka]

[0216] In formula (1A'), R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 111 This is a hydrocarbyl group having 1 to 38 carbon atoms, which may contain heteroatoms. The heteroatoms are preferably oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc., with oxygen atoms being more preferred. The hydrocarbyl group is particularly preferred to have 6 to 30 carbon atoms in order to obtain high resolution in fine pattern formation.

[0217] R 111 The hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples 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 eicosyl; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl Examples include cyclic saturated hydrocarbyl groups with 3 to 38 carbon atoms, such as C3, norbornylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated aliphatic hydrocarbyl groups with 2 to 38 carbon atoms, such as allyl and 3-cyclohexenyl; aryl groups with 6 to 38 carbon atoms, such as phenyl, 1-naphthyl, and 2-naphthyl; aralkyl groups with 7 to 38 carbon atoms, such as benzyl and diphenylmethyl; and groups obtained by combining these.

[0218] 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, sulfur atom, nitrogen atom, or 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, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Examples of hydrocarbyl groups containing heteroatoms include tetrahydrofuryl group, methoxymethyl group, ethoxymethyl group, methylthiomethyl group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy)methyl group, acetoxymethyl group, 2-carboxy-1-cyclohexyl group, 2-oxopropyl group, 4-oxo-1-adamantyl group, and 3-oxocyclohexyl group.

[0219] For details on the synthesis of sulfonium salts containing the anion represented by formula (1A'), please refer to Japanese Patent Publication No. 2007-145797, Japanese Patent Publication No. 2008-106045, Japanese Patent Publication No. 2009-7327, Japanese Patent Publication No. 2009-258695, etc. Also, sulfonium salts described in Japanese Patent Publication No. 2010-215608, Japanese Patent Publication No. 2012-41320, Japanese Patent Publication No. 2012-106986, Japanese Patent Publication No. 2012-153644, etc., can be suitably used.

[0220] The anions represented by formula (1A) include, but are not limited to, those listed below. In the formula below, Ac represents an acetyl group. [ka]

[0221] [ka]

[0222] [ka]

[0223] [ka]

[0224] In formula (1B), R fb1 and R fb2 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (1A'). 111 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fb1 and R fb2 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 This refers to the groups that bond to each other (-CF2-SO2-N - It may also form a ring with (SO2-CF2-), in which case R fb1 and R fb2 The group obtained by the bonding of these two elements is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0225] In formula (1C), R fc1 , R fc2 and R fc3 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (1A'). 111 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fc1 , R fc2 and R fc3 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1and R fc2 This refers to the groups that bond to each other (-CF2-SO2-C - It may form a ring with -SO2-CF2-), in which case R fc1 and R fc2 The group obtained by the bonding of these two elements is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0226] In formula (1D), R fd R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (1A'). 111 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include those shown. The synthesis of sulfonium salts containing the anion represented by formula (1D) is described in detail in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2014-133723.

[0227] The anions represented by formula (1D) include, but are not limited to, those listed below. [ka]

[0228] [ka]

[0229] Furthermore, the photoacid generator containing the anion represented by formula (1D) does not have a fluorine atom at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position, which gives it sufficient acidity to cleave acid-unstable groups in the base polymer. Therefore, it can be used as a photoacid generator.

[0230] As a photoacid generator, one represented by the following formula (2) can also be suitably used. [ka]

[0231] In formula (2), R 201 and R 202 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom. 203 This is a hydrocarbylene group having 1 to 30 carbon atoms, which may contain heteroatoms. Also, R 201 , R 202 and R 203 Any two of these may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, the ring is defined as R in the explanation of formula (1-1). 101 and R 102 Examples of rings that can be formed when these elements combine with the sulfur atom to which they are bonded are similar to those exemplified.

[0232] R 201 and R 202 The hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0 2,6Examples include cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as decyl groups and adamantyl groups; aryl groups having 6 to 30 carbon atoms, such as phenyl groups, methylphenyl groups, ethylphenyl groups, n-propylphenyl groups, isopropylphenyl groups, n-butylphenyl groups, isobutylphenyl groups, sec-butylphenyl groups, tert-butylphenyl groups, naphthyl groups, methylnaphthyl groups, ethylnaphthyl groups, n-propylnaphthyl groups, isopropylnaphthyl groups, n-butylnaphthyl groups, isobutylnaphthyl groups, sec-butylnaphthyl groups, tert-butylnaphthyl groups, anthracenyl groups, and groups obtained by combining these. 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, sulfur atom, nitrogen atom, or 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, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0233] R 203The hydrocarbylene group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkane diyl groups with 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, heptadecane-1,17-diyl group, etc.; cyclopentanediyl group, cyclohex Examples include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as xanediyl, norbornanediyl, and adamantanediyl groups; 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. Furthermore, 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, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- groups of the hydrocarbylene group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, the material may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. The heteroatom is preferably an oxygen atom.

[0234] In formula (2), LA This is a 1-20 carbon atom hydrocarbylene group which may contain single bonds, ether bonds, or heteroatoms. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 203 Examples of hydrocarbylene groups represented by the same formula as those exemplified above include the same groups as those shown.

[0235] In formula (2), X A , X B , X C and X D Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. However, X A , X B , X C and X D At least one of these is a fluorine atom or a trifluoromethyl group.

[0236] In equation (2), k is an integer between 0 and 3.

[0237] The photoacid generator represented by formula (2) is preferably the one represented by formula (2') below. [ka]

[0238] In formula (2'), L A This is the same as above. R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (1A'). 111 Examples of hydrocarbyl groups represented by the formula shown are similar to those exemplified. x and y are each independent integers from 0 to 5, and z is an integer from 0 to 4.

[0239] Examples of photoacid generators represented by formula (2) include those similar to those exemplified as photoacid generators represented by formula (2) in Japanese Patent Publication No. 2017-026980.

[0240] Among the photoacid generators, those containing an anion represented by formula (1A') or (1D) are particularly preferred because they exhibit low acid diffusion and excellent solubility in solvents. Furthermore, those represented by formula (2') are particularly preferred because they exhibit extremely low acid diffusion.

[0241] When the resist material of the present invention contains an additive-type acid generator, its content is preferably 0.1 to 50 parts by mass, and more preferably 1 to 40 parts by mass, per 100 parts by mass of the base polymer. The resist material of the present invention can function as a chemically amplified resist material by the base polymer containing repeating units f and / or by containing an additive-type acid generator.

[0242] [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 the components described later. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] to

[0145] of Japanese Patent Application Publication 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 include ethers such as monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; and lactones such as γ-butyrolactone.

[0243] In the resist material of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, and more preferably 200 to 8,000 parts by mass, per 100 parts by mass of the base polymer. The organic solvent may be used alone or as a mixture of two or more types.

[0244] [Other ingredients] In addition to the components described above, the resist material of the present invention may also contain quenchers other than the cyclic ammonium salt compounds described above (hereinafter also referred to as other quenchers), surfactants, dissolution inhibitors, crosslinking agents, water-repellency enhancers, acetylene alcohols, and the like.

[0245] Examples of other quenchers include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, or tertiary aliphatic amines, hybrid 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, carbamates, etc. Particularly preferred are primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Publication No. 2008-111103, especially amine compounds having a hydroxyl group, ether bond, ester bond, lactone ring, cyano group, or sulfonic acid ester bond, or compounds having a carbamate group described in Japanese Patent Publication No. 3790649. By adding such basic compounds, for example, the diffusion rate of acid in the resist film can be further suppressed or its shape corrected.

[0246] Other quenchers include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids whose α-position is not fluorinated, as described in Japanese Patent Publication No. 2008-158339. Sulfonic acids, imido acids, or methidic acids with α-position fluorinated are necessary for deprotecting the acid-unstable group of carboxylic acid esters, but salt exchange with onium salts whose α-position is not fluorinated releases sulfonic acids or carboxylic acids whose α-position is not fluorinated. Since sulfonic acids and carboxylic acids whose α-position is not fluorinated do not undergo deprotection reactions, they function as quenchers.

[0247] Other quenchers include the polymer-type quencher described in Japanese Patent Publication No. 2008-239918. This enhances the rectangularity of the resist pattern by oriented on the resist film surface. Polymer-type quenchers also have the effect of preventing film thinning of the pattern and rounding of the pattern top when a protective film for immersion lithography is applied.

[0248] If the resist material of the present invention contains other quenchers, their content is preferably 0 to 5 parts by mass, and more preferably 0 to 4 parts by mass, per 100 parts by mass of the base polymer. The other quenchers may be used alone or in combination of two or more.

[0249] Examples of the surfactants mentioned above include those described in paragraphs

[0165] to

[0166] of Japanese Patent Publication No. 2008-111103. By adding a surfactant, the coatability of the resist material can be further improved or controlled. When the resist material of the present invention contains the surfactant, its content is preferably 0.0001 to 10 parts by mass per 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more types.

[0250] When the resist material of the present invention is of the positive type, by incorporating a dissolution inhibitor, the difference in dissolution rate between the exposed and unexposed areas can be further increased, thereby further improving the resolution. Examples of the dissolution inhibitor include compounds in which the hydrogen atoms of the phenolic hydroxyl groups of a compound having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule are substituted with acid-unstable groups in a total proportion of 0 to 100 mol%, or compounds in which the hydrogen atoms of the carboxyl groups of a compound containing a carboxyl group in the molecule are substituted with acid-unstable groups in an average total proportion of 50 to 100 mol%. Specifically, examples include compounds in which the hydrogen atoms of the hydroxyl group or carboxyl group of bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalenecarboxylic acid, adamantanecarboxylic acid, and cholic acid are substituted with acid-unstable groups, as described in paragraphs

[0155] to

[0178] of Japanese Patent Application Publication No. 2008-122932.

[0251] When the resist material of the present invention is of the positive type and contains the dissolution inhibitor, the content thereof is preferably 0 to 50 parts by mass, and 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.

[0252] On the other hand, if the resist material of the present invention is negative type, a negative type pattern can be obtained by adding a crosslinking agent to reduce the dissolution rate of the exposed area. Examples of the crosslinking agent include epoxy compounds, melamine compounds, guanamine compounds, glycoluryl compounds or urea compounds, isocyanate compounds, azide compounds, and compounds containing double bonds such as alkenyloxy groups, which are substituted with at least one group selected from methylol groups, alkoxymethyl groups, and acyloxymethyl groups. These may be used as additives or introduced as pendant groups in the polymer side chains. Compounds containing hydroxyl groups can also be used as crosslinking agents.

[0253] Examples of the epoxy compound include tris(2,3-epoxypropyl) isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0254] Examples of the melamine compounds include hexamethylmelamine, hexamethoxymethylmelamine, compounds in which 1 to 6 methylol groups of hexamethylmelamine are methoxymethylated or mixtures thereof, hexamethoxyethylmelamine, hexaacyloxymethylmelamine, compounds in which 1 to 6 methylol groups of hexamethylmelamine are acyloxymethylated or mixtures thereof.

[0255] Examples of the guanamine compounds include tetramethylolguanamine, tetramethoxymethylguanamine, compounds in which 1 to 4 methylol groups of tetramethylolguanamine are methoxymethylated or mixtures thereof, tetramethoxyethylguanamine, tetraacyloxyguanamine, compounds in which 1 to 4 methylol groups of tetramethylolguanamine are acyloxymethylated or mixtures thereof.

[0256] Examples of glycoluryl compounds include tetramethylol glycoluryl, tetramethoxy glycoluryl, tetramethoxymethyl glycoluryl, compounds in which 1 to 4 methylol groups of tetramethylol glycoluryl are methoxymethylated or mixtures thereof, compounds in which 1 to 4 methylol groups of tetramethylol glycoluryl are acyloxymethylated or mixtures thereof. Examples of urea compounds include tetramethylolurea, tetramethoxymethylurea, compounds in which 1 to 4 methylol groups of tetramethylolurea are methoxymethylated or mixtures thereof, tetramethoxyethylurea, and the like.

[0257] Examples of the isocyanate compounds include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0258] Examples of the aforementioned azide compounds include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0259] Examples of compounds containing the aforementioned 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.

[0260] When the resist material of the present invention is of the negative type and contains the crosslinking agent, the content is preferably 0.1 to 50 parts by mass, and more preferably 1 to 40 parts by mass, per 100 parts by mass of the base polymer. The crosslinking agent may be used alone or in combination of two or more types.

[0261] The water-repellent enhancer improves the water repellency of the resist film surface and can be used in immersion lithography without a topcoat. Preferred water-repellent enhancers include polymers containing alkyl fluoride, polymers containing 1,1,1,3,3,3-hexafluoro-2-propanol residues of a specific structure, and those exemplified in Japanese Patent Publication No. 2007-297590 and Japanese Patent Publication No. 2008-111103 are more preferred. The water-repellent enhancer needs to be soluble in an alkaline developer or an organic solvent developer. The aforementioned water-repellent enhancer having a specific 1,1,1,3,3,3-hexafluoro-2-propanol residue exhibits good solubility in the developer. As a water-repellent enhancer, polymers containing repeating units including amino groups or amine salts are highly effective in preventing acid evaporation in the PEB and thus preventing poor hole pattern opening after development. When the resist material of the present invention contains the water-repellency improving agent, its content is preferably 0 to 20 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the base polymer. The water-repellency improving agent may be used alone or in combination of two or more types.

[0262] Examples of the acetylene alcohols mentioned above include those described in paragraphs

[0179] to

[0182] of Japanese Patent Publication No. 2008-122932. When the resist material of the present invention contains acetylene alcohols, the content is preferably 0 to 5 parts by mass per 100 parts by mass of the base polymer. The acetylene alcohols may be used individually or in combination of two or more types.

[0263] [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 may include a step of forming a resist film on a substrate using the resist material described above, a step of exposing the resist film with high-energy rays, and a step of developing the exposed resist film using a developer.

[0264] First, the resist material of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coating, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating, so that the coating film thickness is 0.01 to 2 μm. This is then pre-baked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0265] Next, the resist film is exposed using high-energy rays. Examples of high-energy rays include ultraviolet rays, far-ultraviolet rays, EB rays, EUV rays with wavelengths of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation. When using ultraviolet rays, far-ultraviolet rays, EUV rays, X-rays, soft X-rays, excimer laser light, gamma rays, or synchrotron radiation as the high-energy rays, the exposure amount is preferably 1 to 200 mJ / cm², either directly or using a mask to form the desired pattern.2 To the extent, more preferably 10 to 100 mJ / cm² 2 Irradiate to the extent of [a certain degree]. When using EB as the high-energy beam, the exposure dose is preferably 0.1 to 100 μC / cm². 2 To a degree, more preferably 0.5 to 50 μC / cm² 2 The pattern is drawn either directly or using a mask to form the desired pattern. The resist material of the present invention is particularly suitable for fine patterning using high-energy rays, including i-rays with a wavelength of 365 nm, KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, gamma rays, and synchrotron radiation, and is especially suitable for fine patterning using EB or EUV.

[0266] In addition to conventional exposure methods, immersion methods can also be used, in which a liquid with a refractive index of 1.0 or higher, such as water, is interposed between the resist film and the projection lens. In this case, a protective film insoluble in water can also be used.

[0267] After exposure, PEB may be performed on a hot plate or in an oven, preferably at 30-150°C for 10 seconds to 30 minutes, more preferably at 50-120°C for 30 seconds to 20 minutes, or it may not be performed.

[0268] After exposure or PEB, the exposed resist film is developed using a developer solution containing 0.1 to 10% by mass, preferably 2 to 5% by mass, of an alkaline aqueous solution 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 conventional methods such as the dip method, puddle method, or spray method, thereby forming the desired pattern. In the case of positive-type resist materials, the areas irradiated with light dissolve in the developer solution, while the unexposed areas do not dissolve, forming the desired positive-type pattern on the substrate. In the case of negative-type resist materials, the opposite is true: the areas irradiated with light become insoluble in the developer solution, while the unexposed areas dissolve.

[0269] Negative patterns can also be obtained by developing with organic solvents using positive-type resist materials containing a base polymer with acid-unstable groups. The developers used in this process include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotate, ethyl crotate, Examples 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 phenyl acetate, and 2-phenylethyl acetate. These organic solvents may be used individually or in mixtures of two or more.

[0270] At the end of development, rinsing is performed. A solvent that mixes with the developer but does not dissolve the resist film is preferred as the rinsing solution. Preferred solvents include C3-C10 alcohols, C8-C12 ether compounds, C6-C12 alkanes, alkenes, alkynes, and aromatic solvents.

[0271] The C3-C10 alcohols 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 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.

[0272] Examples of the ether compounds 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.

[0273] Examples of C6-C12 alkanes include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Examples of C6-C12 alkenes include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of C6-C12 alkynes include hexine, heptine, and octine.

[0274] Examples of the aforementioned aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0275] Rinsing can reduce the occurrence of resist pattern deformation and defects. However, rinsing is not always necessary, and omitting it can reduce the amount of solvent used.

[0276] The developed hole patterns and trench patterns can also be shrunk using thermal flow, RELACS, or DSA techniques. A shrinking agent is applied to the hole pattern, and crosslinking of the shrinking agent occurs on the surface of the resist film due to the diffusion of an acid catalyst from the resist film during baking, causing the shrinking agent to adhere to the side walls 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, during which excess shrinking agent is removed and the hole pattern is reduced in size. [Examples]

[0277] The present invention will be specifically described below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples.

[0278] The structures of quenchers Q-1 to Q-37 used as resist materials are shown below. Quenchers Q-1 to Q-37 were synthesized by mixing compounds that yield the following cations, obtained by esterification of a compound having a carboxyl group and an amine compound having a tertiary hydroxyl group, with fluorinated 1,3-diketone compounds, fluorinated β-ketoester compounds, or fluorinated imide compounds that yield the following anions. [ka]

[0279] [ka]

[0280] [ka]

[0281] [ka]

[0282] Furthermore, the structures of the amine compound (Amine-1) and the fluorinated 1,3-diketone compound (F-AcAc-1) used as the resist material are shown below. [ka]

[0283] [Synthesis Example] Synthesis of Base Polymer (P-1) Each monomer was combined and copolymerized in THF, a solvent. The reaction solution was added to methanol, and the precipitated solid was washed with hexane, then isolated and dried to obtain a base polymer (P-1) with the following composition. The composition of the obtained base polymer (P-1) is: 1 Mw and Mw / Mn were confirmed by H-NMR using GPC (solvent: THF, standard: polystyrene). [ka]

[0284] [Examples 1-41, Comparative Examples 1-6] Preparation and Evaluation of Resist Materials (1) Preparation of resist material A chemically amplified resist material was prepared by dissolving each component in a solvent containing 100 ppm of Polyfox PF-636 manufactured by Omnova as a surfactant, according to the compositions shown in Tables 1-3, and filtering the solution through a 0.2 μm filter.

[0285] In Tables 1-3, the components are as follows: • Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0286] • Acid generator: PAG-1 [ka]

[0287] • Water-repellent enhancer: FP-1 [ka]

[0288] • Comparative Quenchers: cQ-1 to cQ-6 [ka]

[0289] • Blend Quencher: bQ-1, bQ-2 [ka]

[0290] (2) ArF immersion lithography evaluation Each resist material shown in Tables 1-3 was spin-coated onto a silicon wafer coated with Nissan Chemical Corporation's anti-reflective film ARC-29A to a thickness of 78 nm. The wafer was then baked at 100°C for 60 seconds using a hot plate to form a resist film with a thickness of 170 nm. The resist film was exposed using an ArF immersion excimer laser scanner (Nikon Corporation NSR-S610C, NA 1.10, σ 0.98 / 0.78, 35-degree dipole illumination, 6% halftone phase shift mask) with a 1:1 line-and-space (LS) mask with dimensions of 60 nm on the wafer. Water was used as the immersion solution. After exposure, PEB was performed for 60 seconds at the temperatures listed in Tables 1-3, and development was performed with a 2.38 mass% TMAH aqueous solution to form a 1:1 LS pattern with dimensions of 60 nm. The exposure level used to form a 1:1 LS pattern with dimensions of 60 nm was defined as the sensitivity. Furthermore, the dimensions of the LS pattern were measured at 10 points along the longitudinal direction of the space width using a Hitachi High-Tech SEM (CG6300). From these results, three times the standard deviation (σ) (3σ) was calculated and defined as the LWR. The results are shown in Tables 1-3.

[0291] [Table 1]

[0292] [Table 2]

[0293] [Table 3]

[0294] The results shown in Tables 1-3 indicate that the resist material of the present invention, which contains a salt compound comprising an anion derived from a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, or a fluorinated imide compound and a cyclic ammonium cation, exhibits a low LWR (low wall resistance).

Claims

1. A resist material comprising a base polymer and a quencher, A resist material wherein the quencher comprises a salt compound consisting of a cyclic ammonium cation represented by the following formula (A-1) or (A-2) and an anion derived from a fluorinated 1,3-diketone compound, a fluorinated β-ketoester compound, or a fluorinated imide compound. 【Chemistry 1】 (In the formula, m is an integer between 1 and 6.) R 1 When m is 1, it is a hydrocarbyl group having 1 to 30 carbon atoms; when m is 2, it is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms; and when m is an integer from 3 to 6, it is an m-valent hydrocarbon group having 1 to 30 carbon atoms. The hydrocarbyl group, hydrocarbylene group and m-valent hydrocarbon group may include at least one selected from a hydroxyl group, a thiol group, an ester bond, a thioester bond, a thionoester bond, an ether bond, a sulfide bond, a halogen atom other than iodine and bromine, a nitro group, an amino group, an amide bond, a sulfonyl group, a sulfonic acid ester bond, a sultone ring, a lactam ring, and a carbonate bond. R 2 and R 3 Each of these is independently a saturated hydrocarbyl group having 1 to 6 carbon atoms, and R 2 and R 3 These elements may bond with each other to form a ring with the carbon atoms to which they are bonded. R 4 and R 6 Each of these is independently either a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. R 5 This is an aliphatic hydrocarbyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may be substituted with a halogen atom or a trifluoromethyl group. Ring R is an alicyclic group having 2 to 10 carbon atoms, which is formed together with the nitrogen atom in the formula.

2. The resist material according to claim 1, wherein the anion derived from the fluorinated 1,3-diketone compound, the fluorinated β-ketoester compound, or the fluorinated imide compound is represented by the following formula (B). 【Chemistry 2】 (wherein, R 7 and R 8 are each independently a hydrocarbyl group having 1 to 16 carbon atoms, a fluorinated hydrocarbyl group having 1 to 16 carbon atoms, a hydrocarbyloxy group having 1 to 16 carbon atoms, or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, provided that at least one of R 7 and R 8 is a fluorinated hydrocarbyl group having 1 to 16 carbon atoms or a fluorinated hydrocarbyloxy group having 1 to 16 carbon atoms, and some or all of the hydrogen atoms thereof may be substituted with at least one selected from the group consisting of cyano group, nitro group, hydroxy group, and halogen atoms other than fluorine atom, and some of these -CH 2 - may be substituted with at least one selected from the group consisting of ether bond, ester bond, and thioether bond.) X is either -C(H) = or -N =.

3. Furthermore, the resist material according to claim 1 further comprises an acid generator that generates sulfonic acid, imido acid, or methido acid.

4. Furthermore, the resist material according to claim 1, further comprising an organic solvent.

5. The resist material according to claim 1, wherein the base polymer includes a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2). 【Transformation 3】 (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. Y 1 This is a linking group having 1 to 12 carbon atoms, containing at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. Y 2 These are single bonds or ester bonds. Y 3 These are single bonds, ether bonds, or ester bonds. R 11 and R 12 These are, independently, acid-unstable groups. R 13 This is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 This is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and its -CH 2 - may be partially substituted with an ether bond or an ester bond. a is either 1 or 2. b is an integer between 0 and 4, where 1 ≤ a + b ≤ 5.

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

7. The resist material according to claim 1, wherein the base polymer does not contain acid-unstable groups.

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

9. Furthermore, the resist material according to claim 1, further comprising a surfactant.

10. The resist material according to claim 1, wherein the base polymer includes a repeating unit represented by any of the following formulas (f1) to (f3). 【Chemistry 4】 (In the formula, R A Each of these is independently either a hydrogen atom or a methyl group. Z 1 This includes single bonds, aliphatic hydrocarbylene groups having 1 to 6 carbon atoms, phenylene groups, naphthylene groups, or groups 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 This 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 hydroxyl group. Z 2 This is a single bond, -Z 21 -C(=O)-O-, -Z 21 -O- or -Z 21 -O-C(=O)-. Z 21 This is a saturated hydrocarbylene group having 1 to 12 carbon atoms, and may contain a carbonyl group, an ester bond, or an ether bond. Z 3 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, trifluoromethyl groups, and -O-Z. 31 -, -C(=O)-O-Z 31 - or -C(=O)-NH-Z 31 - is Z 31 This is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. R 21 ~R 28 Each of these is independently a C1-C20 hydrocarbyl group which may contain a halogen atom or a heteroatom. 23 and R 24 or R 26 and R 27 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. R HF This is either a hydrogen atom or a trifluoromethyl group. M - (It is a non-nucleophilic counterion.)

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

12. The pattern forming method according to claim 11, wherein the high-energy ray is an i-ray with a wavelength of 365 nm, ArF excimer laser light with a wavelength of 193 nm, KrF excimer laser light with a wavelength of 248 nm, an electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

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