Positive resist material and pattern forming method

Abstract

To provide a positive resist material that has sensitivity surpassing that of the conventional positive resist material, and is small in edge roughness (LWR) and critical dimension uniformity (CDU) of an exposure pattern, and a patterning method using the same.SOLUTION: A positive resist material comprises an acid generator of a sulfonium salt of a sulfonic acid ion bound to a polymer main chain, and a quencher of a sulfonium salt represented by the following general formula (1) (where R1 is a fluorine atom, a phenyl group, a phenyloxycarbonyl group, or an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group, or an alkoxycarbonyl group, and R2-R4 independently represent a halogen atom or a hydrocarbyl group).SELECTED DRAWING: None

Description

[Technical field]

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

[0002] As LSIs become more highly integrated and faster, pattern rules are becoming finer at a rapid pace. In particular, the expansion of the logic memory market due to the spread of smartphones is driving miniaturization. The most advanced miniaturization technologies currently underway include mass production of 7nm node devices using double patterning with ArF immersion lithography, and 5nm node devices using extreme ultraviolet (EUV) lithography. EUV lithography is also being considered as a candidate for the next-generation 3nm node and the generation after that, the 2nm node.

[0003] The wavelength of EUV, 13.5 nm, is 1 / 14.3 of the wavelength of ArF excimer laser, 193 nm, which enables the formation of fine patterns. However, the number of photons in EUV exposure is 1 / 14.3 of that in ArF exposure, so there is a shot noise problem in which the line edge roughness (LWR) increases due to the variation in the number of photons, and the dimensional uniformity (CDU) decreases (Non-Patent Document 1).

[0004] It has been pointed out that in addition to the variation due to shot noise, the variation in dimensions is due to the variation in the acid generator and quencher components in the resist film (Non-Patent Document 2). In EUV lithography, which forms extremely fine dimensions, a resist with a uniform dispersion system is required.

[0005] The introduction of fluorine into the cation moiety of sulfonium salts used in acid generators and quenchers has been investigated (Patent Document 1). It has been shown that the introduction of fluorine into the cation moiety of sulfonium salts not only increases the absorption of EUV light, but also improves the decomposition efficiency, resulting in high sensitivity (Patent Document 2).

[0006] A method for producing a sulfonium salt of a weak acid has been proposed (Patent Document 3). When a sulfonium salt of a weak acid is used as a quencher, the generated acid swells little in an alkaline developer, so that pattern collapse and an increase in edge roughness (LWR) can be prevented. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2017-015777 A [Patent Document 2] JP 2015-200886 A [Patent Document 3] WO2020 / 175495 publication [Non-patent literature]

[0008] [Non-Patent Document 1] SPIE Vol. 3331 p531 (1998) [Non-Patent Document 2] SPIE Vol. 9776 p97760V-1 (2016) Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a positive resist material that has sensitivity exceeding that of conventional positive resist materials and exhibits small line edge roughness (LWR) and constant dimension variation (CDU) of an exposure pattern, and a pattern formation method using the same. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides The present invention provides a positive resist material that contains an acid generator that is a sulfonium salt of a sulfonic acid ion bonded to a polymer main chain, and a quencher that is a sulfonium salt represented by the following general formula (1): [ka] (In the formula, R 1 is a fluorine atom, a phenyl group, a phenyloxycarbonyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 4 carbon atoms, or an alkoxycarbonyl group having 1 to 20 carbon atoms, and a part or all of the hydrogen atoms of the alkyl group, alkoxy group, alkenyl group, alkynyl group, and alkoxycarbonyl group are each independently selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a R may be substituted with one or more groups selected from a cyano group, a nitro group, a phenyl group, and a hydroxy group, or may have an ester group, an ether group, or a sulfonyl group, and some or all of the hydrogen atoms of the phenyl group and the phenyloxycarbonyl group may be substituted with one or more groups selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a fluorinated alkyl group having 1 to 4 carbon atoms, a fluorinated alkyloxy group having 1 to 4 carbon atoms, a trifluoromethylthio group, a cyano group, a nitro group, and a hydroxy group. 2 ~R 4 are each independently a halogen atom or a hydrocarbyl group having 1 to 25 carbon atoms, and the hydrocarbyl group may have at least one atom selected from an oxygen atom, a sulfur atom, a nitrogen atom, and a halogen atom. 2 and R 3 and, or R 2 and R 4 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0011] Such a positive resist material has sensitivity and resolution superior to conventional positive resist materials, has small line edge roughness (LWR) and constant dimension variation (CDU), and produces a good pattern shape after exposure.

[0012] The acid generator bonded to the polymer main chain is preferably contained in a base polymer that includes repeating units represented by the following general formula (a1) and / or (a2). [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. 1 is a single bond, an ester bond, or a phenylene group. 2 is a single bond, -Z 21 -C(=O)-O-, -Z 21 -O- or -Z 21 -OC(=O)-. Z 21 Z is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, a sulfur atom, an oxygen atom, a bromine atom, or an iodine atom. 3 Z is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, a hydrocarbon group having 2 to 4 carbon atoms which may be substituted with fluorine, or a carbonyl group. 4 represents a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group or an iodine atom, -Z 41 -, -OZ 41 -, -C(=O)-OZ 41 - or -C(=O)-NH-Z 41 -It is. 41 R is a hydrocarbylene group which may contain a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group or an iodine atom, an ester group having 1 to 15 carbon atoms substituted with a halogen atom, and / or an aromatic hydrocarbon group. 5 ~R 7 are each independently a hydrocarbyl group having 1 to 25 carbon atoms, and may have an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom other than fluorine. 5 and R 6 and, or R 5 and R 7 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0013] It is also preferred that the base polymer contains a repeating unit in which the hydrogen atom of a carboxy group represented by the following general formula (b1) is substituted with an acid labile group and / or a repeating unit in which the hydrogen atom of a phenolic hydroxy group represented by the following general formula (b2) is substituted with an acid labile group. [ka] (In the formula, R A Each of Y is independently a hydrogen atom or a methyl group. 1 Y is a linking group having 1 to 15 carbon atoms and containing at least one bond selected from a single bond, a phenylene group, a naphthylene group, an ester bond, an ether bond, and a lactone ring. 2 is a single bond, an ester bond or an amide bond. 3 R is a single bond, an ether bond or an ester bond. 11 , R 12 is an acid labile group. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of whose carbon atoms may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4, with the proviso that 1≦a+b≦5.

[0014] Such a positive resist material can further improve the effects of the present invention.

[0015] It is also preferable that the base polymer further contains a repeating unit containing an adhesive group selected from a hydroxy group, a carboxy group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonate ester bond, a cyano group, an amide bond, -OC(=O)-S-, and -OC(=O)-NH-.

[0016] Such a positive resist material can improve adhesion.

[0017] Furthermore, it is preferable that the composition contains at least one of an acid generator other than the above-mentioned sulfonium salt acid generator, an organic solvent, a quencher other than the above-mentioned sulfonium salt quencher, and a surfactant.

[0018] If this is the case, the positive resist material of the present invention will be effective as a chemically amplified positive resist material.

[0019] The present invention also provides a pattern formation method including the steps of forming a resist film on a substrate using the above-mentioned positive resist material, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer.

[0020] The high energy beam is preferably an i-beam, a KrF excimer laser beam, an ArF excimer laser beam, an electron beam, or an extreme ultraviolet ray having a wavelength of 3 to 15 nm.

[0021] According to this pattern forming method, the desired positive pattern can be formed satisfactorily. Effect of the Invention

[0022] The positive resist material of the present invention is a resist material that combines a sulfonium hydrochloride generator in which fluorosulfonic acid is bonded to a polymer main chain and a quencher of a sulfonium salt of a fluoroalcohol (fluoroalkoxide ion) having a specific structure. The sulfonium salt in which fluorosulfonic acid is bonded to a polymer main chain can control the acid diffusion of the generated fluorosulfonic acid, and the quencher of the sulfonium salt of a fluoroalcohol has small swelling in an alkaline developer and high water repellency, so it is not easily affected by stress during rinsing with pure water, and as a result, pattern collapse is unlikely to occur and LWR is good. Therefore, since it has these excellent properties, it is extremely useful, and is particularly useful as a fine pattern forming material for photomasks for VLSI manufacturing or EB (electron beam) drawing, and a pattern forming material for EB or EUV exposure. The positive resist material of the present invention can be applied, for example, not only to lithography in semiconductor circuit formation, but also to the formation of mask circuit patterns, micromachines, and thin film magnetic head circuits. [Brief description of the drawings]

[0023] [Figure 1] Nuclear magnetic resonance spectrum data (1H-NMR) of the synthesized quencher Q-1. [Diagram 2] Nuclear magnetic resonance spectrum data (19F-NMR) of the synthesized quencher Q-1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] In recent years, there has been a demand for a positive resist material that meets the demand for high resolution, has small edge roughness and dimensional variation, and is less susceptible to bridging between patterns and pattern collapse.

[0025] As a result of extensive research, the present inventors have come to the conclusion that it is effective to suppress acid diffusion to the utmost, to suppress swelling during development, and to reduce stress during drying of the developer rinse solution. They have found that it is effective to combine an acid generator of a sulfonium salt of a sulfonic acid bonded to the polymer main chain with a quencher of a sulfonium salt of a fluoroalcohol having a specific structure, and have completed the present invention.

[0026] That is, the present invention provides: The positive resist material contains an acid generator that is a sulfonium salt of a sulfonic acid ion bonded to a polymer main chain, and a quencher that is a sulfonium salt represented by the following general formula (1). [ka] (In the formula, R 1 is a fluorine atom, a phenyl group, a phenyloxycarbonyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 4 carbon atoms, or an alkoxycarbonyl group having 1 to 20 carbon atoms, and a part or all of the hydrogen atoms of the alkyl group, alkoxy group, alkenyl group, alkynyl group, and alkoxycarbonyl group are each independently selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a R may be substituted with one or more groups selected from a cyano group, a nitro group, a phenyl group, and a hydroxy group, or may have an ester group, an ether group, or a sulfonyl group, and some or all of the hydrogen atoms of the phenyl group and the phenyloxycarbonyl group may be substituted with one or more groups selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a fluorinated alkyl group having 1 to 4 carbon atoms, a fluorinated alkyloxy group having 1 to 4 carbon atoms, a trifluoromethylthio group, a cyano group, a nitro group, and a hydroxy group. 2 ~R 4 are each independently a halogen atom or a hydrocarbyl group having 1 to 25 carbon atoms, and the hydrocarbyl group may have at least one atom selected from an oxygen atom, a sulfur atom, a nitrogen atom, and a halogen atom. 2 and R3 and, or R 2 and R 4 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0027] The present invention will be described in detail below, but the present invention is not limited thereto.

[0028] [Positive resist material] The positive resist material of the present invention includes an acid generator of a sulfonium salt of a sulfonate ion bonded to a polymer main chain, and a quencher of a sulfonium salt of a fluoroalcohol having a specific structure. The acid generator of a sulfonium salt of a sulfonate ion bonded to a polymer main chain has excellent acid diffusion control ability, and the quencher of a sulfonium salt of a fluoroalcohol having a specific structure contains a large amount of fluorine, so that aggregation of the quencher is unlikely to occur due to repulsion between fluorines, and since the fluoroalcohol has small swelling in an alkaline developer and high water repellency, it is possible to reduce the stress applied to the pattern during drying of the pure water rinse after development. This improves the LWR and CDU of the resist pattern after development, and prevents pattern collapse and bridging between patterns.

[0029] [Quenchers of sulfonium salts of fluoroalcohols] The quencher of the sulfonium salt of a fluoroalcohol is a quencher of the sulfonium salt represented by the following general formula (1). [ka] (In the formula, R 1is a fluorine atom, a phenyl group, a phenyloxycarbonyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 4 carbon atoms, or an alkoxycarbonyl group having 1 to 20 carbon atoms, and a part or all of the hydrogen atoms of the alkyl group, alkoxy group, alkenyl group, alkynyl group, and alkoxycarbonyl group are each independently selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a R may be substituted with one or more groups selected from a cyano group, a nitro group, a phenyl group, and a hydroxy group, or may have an ester group, an ether group, or a sulfonyl group, and some or all of the hydrogen atoms of the phenyl group and the phenyloxycarbonyl group may be substituted with one or more groups selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a fluorinated alkyl group having 1 to 4 carbon atoms, a fluorinated alkyloxy group having 1 to 4 carbon atoms, a trifluoromethylthio group, a cyano group, a nitro group, and a hydroxy group. 2 ~R 4 are each independently a halogen atom or a hydrocarbyl group having 1 to 25 carbon atoms, and the hydrocarbyl group may have at least one atom selected from an oxygen atom, a sulfur atom, a nitrogen atom, and a halogen atom. 2 and R 3 and, or R 2 and R 4 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0030] Here, R 1is a fluorine atom, a phenyl group, a phenyloxycarbonyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 4 carbon atoms, or an alkoxycarbonyl group having 1 to 20 carbon atoms. A part or all of the hydrogen atoms of the alkyl group, alkoxy group, alkenyl group, alkynyl group, and alkoxycarbonyl group may be substituted with one or more selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a cyano group, a nitro group, a phenyl group, and a hydroxy group, or may have an ester group, an ether group, or a sulfonyl group. In addition, the hydrogen atoms (R 1 A portion or all of the hydrogen atoms of the phenyl group contained in may be substituted with one or more selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a fluorinated alkyl group having 1 to 4 carbon atoms or a fluorinated alkyloxy group having 1 to 4 carbon atoms, a trifluoromethylthio group, a cyano group, a nitro group and a hydroxy group.

[0031] The carbon chain of the alkyl group, alkoxy group, alkenyl group, alkynyl group, and alkoxycarbonyl group may be linear, branched, or cyclic, and is not particularly limited. Examples of the alkyl group and alkoxycarbonyl group in which hydrogen atoms are replaced by phenyl groups include benzyl group, benzyloxy group, and benzyloxycarbonyl group, in which some or all of the hydrogen atoms of the phenyl group may be replaced by one or more selected from the above atoms or groups.

[0032] Also, R 2 ~R 4 are each independently a halogen atom or a hydrocarbyl group having 1 to 25 carbon atoms, and the hydrocarbyl group may have at least one atom selected from an oxygen atom, a sulfur atom, a nitrogen atom, and a halogen atom. 2 and R 3 and, or R 2 and R 4and may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0033] Examples of the alkoxide ion represented by the above general formula (1) include, but are not limited to, those shown below. [ka]

[0034] [ka]

[0035] [ka]

[0036] [ka]

[0037] [ka]

[0038] Examples of the cation of the sulfonium salt represented by the above general formula (1) include, but are not limited to, those shown below. [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042]

change

[0043]

change

[0044]

change

[0045]

change

[0046]

change

[0047]

change

[0048]

change

[0049]

change

[0050]

change

[0051]

change

[0052] [ka]

[0053] [ka]

[0054] [ka]

[0055] [ka]

[0056] [Acid generators of sulfonium salts of sulfonic acid ions bound to the polymer main chain] As the acid generator of the sulfonium salt bonded to the polymer main chain, a sulfonium salt of fluorosulfonic acid is preferable, and is represented by the following general formula (a1) or (a2). [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. 1 is a single bond, an ester bond, or a phenylene group. 2 is a single bond, -Z 21 -C(=O)-O-, -Z 21 -O- or -Z 21 -OC(=O)-. Z 21 Z is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, a sulfur atom, an oxygen atom, a bromine atom, or an iodine atom. 3 Z is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, a hydrocarbon group having 2 to 4 carbon atoms which may be substituted with fluorine, or a carbonyl group. 4 represents a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group or an iodine atom, -Z41 -, -OZ 41 -, -C(=O)-OZ 41 - or -C(=O)-NH-Z 41 -It is. 41 R is a hydrocarbylene group which may contain a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group or an iodine atom, an ester group having 1 to 15 carbon atoms substituted with a halogen atom, and / or an aromatic hydrocarbon group. 5 ~R 7 are each independently a hydrocarbyl group having 1 to 25 carbon atoms, and may have an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom other than fluorine. 5 and R 6 and, or R 5 and R 7 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0057] Hereinafter, the repeating unit represented by the above general formula (a1) will be referred to as repeating unit a1, and the repeating unit represented by the above general formula (a2) will be referred to as repeating unit a2.

[0058] The number of fluorine atoms in the sulfonate ions of the repeating units a1 and a2 is preferably one or more, more preferably two or more, further preferably three or more, and particularly preferably four or more.

[0059] Examples of the anion of the monomer that gives the repeating unit a1 include, but are not limited to, those shown below. A is the same as above.

[0060] [ka]

[0061] [ka]

[0062] [ka]

[0063] [ka]

[0064] [ka]

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] Examples of the anion of the monomer that gives the repeating unit a2 include, but are not limited to, those shown below. A is the same as above. [ka]

[0073] [ka]

[0074] Examples of the cations of the sulfonium salt of the repeating units a1 and a2 include, but are not limited to, the structures of the sulfonium salt cations represented by the above general formula (1) that do not contain a fluorine atom.

[0075] In addition, it is preferable that the base polymer contains a repeating unit in which a hydrogen atom of a carboxy group is substituted with an acid labile group and / or a repeating unit in which a hydrogen atom of a phenolic hydroxy group is substituted with an acid labile group, and these repeating units are represented by the following general formula (b1) and the following general formula (b2), respectively. [ka] (In the formula, R A Each of Y is independently a hydrogen atom or a methyl group. 1 Y is a linking group having 1 to 15 carbon atoms and containing at least one bond selected from a single bond, a phenylene group, a naphthylene group, an ester bond, an ether bond, and a lactone ring. 2 is a single bond, an ester bond or an amide bond. 3 R is a single bond, an ether bond or an ester bond. 11 , R 12 is an acid labile group. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of whose carbon atoms may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4, with the proviso that 1≦a+b≦5.

[0076] Examples of monomers that provide the repeating unit represented by formula (b1) (repeating unit b1) include, but are not limited to, those shown below. A and R 11 is the same as above.

[0077] [ka]

[0078] [ka]

[0079] Examples of monomers that provide the repeating unit represented by formula (b2) (repeating unit b2) include, but are not limited to, those shown below. A and R 12 is the same as above. [ka]

[0080] R 11 or R 12 The acid labile group represented by the formula (AL-1) may be selected from various groups, and examples thereof include those represented by the following general formulae (AL-1) to (AL-3). [ka]

[0081] In the above general formula (AL-1), c is an integer of 0 to 6. L1 is a tertiary hydrocarbyl group having 4 to 61, preferably 4 to 15, carbon atoms, a trihydrocarbylsilyl group in which each hydrocarbyl group is a saturated hydrocarbyl group having 1 to 6 carbon atoms, a carbonyl group, a saturated hydrocarbyl group containing an ether bond or an ester bond and having 4 to 20 carbon atoms, or a group represented by formula (AL-3).

[0082] RL1 The tertiary hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, branched or cyclic. Specific examples thereof include tert-butyl group, tert-pentyl group, 1,1-diethylpropyl group, 1-ethylcyclopentyl group, 1-butylcyclopentyl group, 1-ethylcyclohexyl group, 1-butylcyclohexyl group, 1-ethyl-2-cyclopentenyl group, 1-ethyl-2-cyclohexenyl group, and 2-methyl-2-adamantyl group. Examples of the trialkylsilyl group (trihydrocarbylsilyl group) include trimethylsilyl group, triethylsilyl group, and dimethyl-tert-butylsilyl group. The saturated hydrocarbyl group containing the carbonyl group, ether bond or ester bond may be linear, branched or cyclic, but is preferably cyclic. Specific examples thereof include a 3-oxocyclohexyl group, a 4-methyl-2-oxooxan-4-yl group, a 5-methyl-2-oxooxolan-5-yl group, a 2-tetrahydropyranyl group and a 2-tetrahydrofuranyl group.

[0083] Examples of the acid labile group represented by the above general formula (AL-1) include a tert-butoxycarbonyl group, a tert-butoxycarbonylmethyl group, a tert-pentyloxycarbonyl group, a tert-pentyloxycarbonylmethyl group, a 1,1-diethylpropyloxycarbonyl group, a 1,1-diethylpropyloxycarbonylmethyl group, a 1-ethylcyclopentyloxycarbonyl group, a 1-ethylcyclopentyloxycarbonylmethyl group, a 1-ethyl-2-cyclopentenyloxycarbonyl group, a 1-ethyl-2-cyclopentenyloxycarbonylmethyl group, a 1-ethoxyethoxycarbonylmethyl group, a 2-tetrahydropyranyloxycarbonylmethyl group, and a 2-tetrahydrofuranyloxycarbonylmethyl group.

[0084] Further, examples of the acid labile group represented by the above general formula (AL-1) include groups represented by the following general formulas (AL-1)-1 to (AL-1)-10. [ka] (In the formula, the dashed lines represent bonds.)

[0085] In the above general formulas (AL-1)-1 to (AL-1)-10, c is the same as above. L8 R is each independently a saturated hydrocarbyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. L9 R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. L10 is a saturated hydrocarbyl group having 2 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic.

[0086] In the above general formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10. The saturated hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, and an n-octyl group.

[0087] In the above general formula (AL-2), R L2 is a hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10, which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples of the hydrocarbyl group include saturated hydrocarbyl groups having 1 to 18 carbon atoms, and some of the hydrogen atoms may be substituted with a hydroxy group, an alkoxy group, an oxo group, an amino group, an alkylamino group, or the like. Examples of such substituted saturated hydrocarbyl groups include those shown below. [ka] (In the formula, the dashed lines represent bonds.)

[0088] R L2 and RL3 And, R L2 and R L4 and, or R L3 and R L4 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, or together with the carbon atom and the oxygen atom, in which case, R L2 and R L3 , R L2 and R L4 , or R L3 and R L4 are each independently an alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10. The number of carbon atoms in the ring obtained by bonding these is preferably 3 to 10, more preferably 4 to 10.

[0089] Among the acid labile groups represented by the above general formula (AL-2), linear or branched ones include, but are not limited to, those represented by the following formulae (AL-2)-1 to (AL-2)-69, in which the dashed lines represent bonds. [ka]

[0090] [ka]

[0091] [ka]

[0092] [ka]

[0093] Among the acid labile groups represented by the above general formula (AL-2), examples of cyclic groups include a tetrahydrofuran-2-yl group, a 2-methyltetrahydrofuran-2-yl group, a tetrahydropyran-2-yl group, and a 2-methyltetrahydropyran-2-yl group.

[0094] Further, examples of the acid labile group include crosslinked acetal groups represented by the following general formula (AL-2a) or (AL-2b): The base polymer may be inter- or intramolecularly crosslinked by the acid labile group. [ka] (In the formula, the dashed lines represent bonds.)

[0095] In the above general formula (AL-2a) or (AL-2b), R L11 and R L12 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 8 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. L11 and R L12 may be bonded to each other to form a ring together with the carbon atom to which they are attached, in which case R L11 and R L12 R is each independently an alkanediyl group having 1 to 8 carbon atoms. L13 are each independently a saturated hydrocarbylene group having 1 to 10 carbon atoms. The saturated hydrocarbylene group may be linear, branched, or cyclic. d and e are each independently an integer of 0 to 10, preferably an integer of 0 to 5, and f is an integer of 1 to 7, preferably an integer of 1 to 3.

[0096] In the above general formula (AL-2a) or (AL-2b), L A is a (f+1)-valent aliphatic saturated hydrocarbon group having 1 to 50 carbon atoms, a (f+1)-valent alicyclic saturated hydrocarbon group having 3 to 50 carbon atoms, a (f+1)-valent aromatic hydrocarbon group having 6 to 50 carbon atoms, or a (f+1)-valent heterocyclic group having 3 to 50 carbon atoms. In addition, some of the carbon atoms of these groups may be substituted with a heteroatom-containing group, and some of the hydrogen atoms bonded to the carbon atoms of these groups may be substituted with a hydroxy group, a carboxy group, an acyl group, or a fluorine atom. AAs L, saturated hydrocarbon groups such as saturated hydrocarbylene groups having 1 to 20 carbon atoms, trivalent saturated hydrocarbon groups, and tetravalent saturated hydrocarbon groups, and arylene groups having 6 to 30 carbon atoms are preferred. The saturated hydrocarbon groups may be linear, branched, or cyclic. B is -C(=O)-O-, -NH-C(=O)-O- or -NH-C(=O)-NH-.

[0097] Examples of the crosslinked acetal group represented by the above general formula (AL-2a) or (AL-2b) include groups represented by the following formulae (AL-2)-70 to (AL-2)-77. [ka] (In the formula, the dashed lines represent bonds.)

[0098] In the above general formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cyclic unsaturated hydrocarbyl group having 3 to 20 carbon atoms, and an aryl group having 6 to 10 carbon atoms. In addition, R L5 and R L6 And, R L5 and R L7 and, or R L6 and R L7 may be bonded to each other to form an alicyclic ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.

[0099] Examples of the group represented by the above general formula (AL-3) include a tert-butyl group, a 1,1-diethylpropyl group, a 1-ethylnorbornyl group, a 1-methylcyclopentyl group, a 1-isopropylcyclopentyl group, a 1-ethylcyclopentyl group, a 1-methylcyclohexyl group, a 2-(2-methyl)adamantyl group, a 2-(2-ethyl)adamantyl group, and a tert-pentyl group.

[0100] Further, examples of the group represented by the above general formula (AL-3) include groups represented by the following general formulae (AL-3)-1 to (AL-3)-19. [ka] (In the formula, the dashed lines represent bonds.)

[0101] In the above general formulas (AL-3)-1 to (AL-3)-19, R L14 R are each independently a saturated hydrocarbyl group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms. L15 and R L17 R are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms. L16 R is an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. The aryl group is preferably a phenyl group. F is a fluorine atom or a trifluoromethyl group, and g is an integer of 1 to 5.

[0102] Further examples of the acid labile group include groups represented by the following general formula (AL-3)-20 or (AL-3)-21: The acid labile group may cause intramolecular or intermolecular crosslinking of the polymer. [ka] (In the formula, the dashed lines represent bonds.)

[0103] In the above general formulas (AL-3)-20 and (AL-3)-21, R L14 is the same as above. R L18is a (h+1)-valent saturated hydrocarbylene group having 1 to 20 carbon atoms or a (h+1)-valent arylene group having 6 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. The saturated hydrocarbylene group may be linear, branched, or cyclic. h is an integer of 1 to 3.

[0104] Examples of monomers that provide repeating units containing an acid labile group represented by the above general formula (AL-3) include (meth)acrylic acid esters containing an exo structure represented by the following general formula (AL-3)-22. [ka]

[0105] In the above general formula (AL-3)-22, R A is the same as above. R Lc1 R is a saturated hydrocarbyl group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms which may be substituted. The saturated hydrocarbyl group may be linear, branched or cyclic. Lc2 ~R Lc11 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 15 carbon atoms which may contain a heteroatom. Examples of the heteroatom include an oxygen atom. Examples of the hydrocarbyl group include an alkyl group having 1 to 15 carbon atoms and an aryl group having 6 to 15 carbon atoms. R Lc2 and R Lc3 And, R Lc4 and R Lc6 And, R Lc4 and R Lc7 And, R Lc5 and R Lc7 And, R Lc5 and R Lc11 And, R Lc6 and R Lc10 And, R Lc8 and R Lc9 and, or R Lc9 and R Lc10 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, and in this case, the group participating in the bond is a hydrocarbylene group having 1 to 15 carbon atoms which may contain a heteroatom.Lc2 and R Lc11 And, R Lc8 and R Lc11 and, or R Lc4 and R Lc6 The carbon atoms bonded to adjacent carbons may bond directly to each other to form a double bond. This formula also represents an enantiomer.

[0106] Here, examples of monomers that provide the repeating unit represented by the above general formula (AL-3)-22 include those described in JP-A-2000-327633. Specific examples include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0107] Examples of monomers that provide repeating units containing an acid labile group represented by the above general formula (AL-3) include (meth)acrylic acid esters containing a furandiyl group, a tetrahydrofurandiyl group, or an oxanorbornanediyl group represented by the following general formula (AL-3)-23. [ka]

[0108] In the above general formula (AL-3)-23, R A is the same as above. R Lc12 and R Lc13 R is each independently a hydrocarbyl group having 1 to 10 carbon atoms. Lc12 and R Lc13 may be bonded to each other to form an alicyclic ring together with the carbon atom to which they are attached. Lc14 R is a furandiyl group, a tetrahydrofurandiyl group, or an oxanorbornanediyl group. Lc15is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be linear, branched, or cyclic. Specific examples thereof include saturated hydrocarbyl groups having 1 to 10 carbon atoms.

[0109] Examples of monomers that provide the repeating unit represented by the above general formula (AL-3)-23 include, but are not limited to, those shown below. A is the same as above, Ac is an acetyl group, and Me is a methyl group. [ka]

[0110] [ka]

[0111] The base polymer may further include a repeating unit c having an adhesive group selected from a hydroxy group, a carboxy group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonate ester bond, a cyano group, an amide group, -OC(=O)-S-, and -OC(=O)-NH-.

[0112] Examples of monomers that provide the repeating unit c include, but are not limited to, those shown below. In the following formula, R A is the same as above.

[0113] [ka]

[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] [ka]

[0118] [ka]

[0119] [ka]

[0120] [ka]

[0121] The base polymer may contain a repeating unit d other than the repeating units described above. Examples of the repeating unit d include those derived from styrene, acenaphthylene, indene, coumarin, coumarone, and the like.

[0122] In the above base polymer, the contents of the repeating units a1, a2, b1, b2, c and d are preferably 0≦a1<1.0, 0≦a2<1.0, 0.01≦a1+a2<1.0, 0≦b1≦0.9, 0≦b2≦0.9, 0.1≦b1+b2≦0.9, 0≦c≦0.9 and 0≦d≦0.5, and more preferably 0≦a1≦0.6, 0≦a2<0.6, 0.02≦a More preferably, 1+a2≦0.6, 0≦b1≦0.8, 0≦b2≦0.8, 0.2≦b1+b2≦0.8, 0≦c≦0.8, and 0≦d≦0.4, and even more preferably, 0≦a1≦0.5, 0≦a2<0.5, 0.03≦a1+a2≦0.5, 0≦b1≦0.7, 0≦b2≦0.7, 0.3≦b1+b2≦0.7, 0≦c≦0.7, and 0≦d≦0.3, with the proviso that a1+a2+b1+b2+c+d=1.0.

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

[0124] Examples of the organic solvent used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The temperature during polymerization is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, and more preferably 5 to 20 hours.

[0125] When a monomer containing a hydroxy group is copolymerized, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid, such as an ethoxy group, during polymerization, and then deprotected with a weak acid and water after polymerization; alternatively, the hydroxy group may be substituted with an acetyl group, a formyl group, a pivaloyl group, or the like, and then subjected to alkaline hydrolysis after polymerization.

[0126] When hydroxystyrene or hydroxyvinylnaphthalene is copolymerized, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group may be deprotected by the above-mentioned alkaline hydrolysis to give hydroxystyrene or hydroxyvinylnaphthalene.

[0127] As the base for the alkaline hydrolysis, ammonia water, triethylamine, etc. can be used. The reaction temperature is preferably −20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0128] The base polymer has a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) using THF as a solvent of preferably 1,000 to 500,000, more preferably 2,000 to 30,000. If the Mw is 1,000 or more, the resist material will have excellent heat resistance, and if it is 500,000 or less, the alkali solubility will not decrease and the footing phenomenon will not be easily caused after pattern formation.

[0129] Furthermore, when the base polymer has a molecular weight distribution (Mw / Mn) of 1.0 to 2.0, there is no low molecular weight or high molecular weight polymer present, so there is no risk of foreign matter being found on the pattern or the shape of the pattern being deteriorated after exposure. As the pattern rule becomes finer, the effects of Mw and Mw / Mn tend to become greater, so in order to obtain a resist material that is suitable for use with fine pattern dimensions, it is preferable that the base polymer has a narrow distribution of Mw / Mn of 1.0 to 2.0, particularly 1.0 to 1.5.

[0130] The base polymer may include two or more polymers having different composition ratios, Mw, or Mw / Mn. Also, a polymer containing repeating units a1 and / or a2 may be blended with a polymer not containing repeating units a1 and a2 but containing repeating units b1 and / or b2.

[0131] [Additive-type acid generator] The positive resist material of the present invention may further contain an acid generator (hereinafter also referred to as an additive-type acid generator) that generates a strong acid other than the sulfonium salt of the sulfonic acid ion bonded to the polymer main chain described above. The strong acid here means a compound having sufficient acidity to cause a deprotection reaction of the acid labile group of the base polymer. The acid generator may be, for example, a compound (photoacid generator) that generates an acid in response to actinic rays or radiation. The photoacid generator is not particularly limited as long as it generates an acid upon irradiation with high-energy rays, but it is preferable that it generates a sulfonic acid, an imide acid, or a methide acid. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators. Specific examples of photoacid generators include those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A.

[0132] In addition, as the photoacid generator, a sulfonium salt represented by the following general formula (10-1) or an iodonium salt represented by the following general formula (10-2) can also be suitably used. [ka]

[0133] In the above general formulas (10-1) and (10-2), R 101 ~R 105 X each independently represents a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, or a hydrocarbyl group having 1 to 25 carbon atoms which may contain a heteroatom. - is an anion.

[0134] R 101 ~R 105The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, or an icosyl group; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, or an adamantyl group; and alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, a propenyl group, a butenyl group, or a hexenyl group. groups; cyclic unsaturated aliphatic hydrocarbyl groups having 2 to 20 carbon atoms, such as a cyclohexenyl group, norbornenyl group, etc.; alkynyl groups having 2 to 20 carbon atoms, such as an ethynyl group, a propynyl group, a butynyl group, etc.; aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, a n-propylphenyl group, an isopropylphenyl group, a n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, a n-propylnaphthyl group, an isopropylnaphthyl group, a n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, a tert-butylnaphthyl group, etc.; and aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group, a phenethyl group, etc. In addition, a portion of the hydrogen atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and a portion of the carbon atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom or a nitrogen atom, so that the groups may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0135] Also, R 101 and R 102may be bonded to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is preferably one having the structure shown below. [ka] (In the formula, the dashed line represents R 103 It is a bond with .)

[0136] Examples of the cation of the sulfonium salt represented by the above general formula (10-1) include the same as those mentioned above, but are not limited thereto.

[0137] Examples of the cation of the iodonium salt represented by the above general formula (10-2) include, but are not limited to, those shown below. [ka]

[0138] In the above general formulas (10-1) and (10-2), X - is an anion selected from the following general formulas (1A) to (1D). [ka]

[0139] In the above general formula (1A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 107 Examples of the hydrocarbyl group represented by the formula (I) include the same as those described below.

[0140] The anion represented by the above general formula (1A) is preferably one represented by the following general formula (1A'). [ka]

[0141] In the above general formula (1A'), R 106 R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 107 is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and more preferably an oxygen atom. The hydrocarbyl group is preferably one having 6 to 30 carbon atoms, in order to obtain high resolution in the formation of a fine pattern.

[0142] R 107 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosanyl groups; cyclic saturated hydrocarbyl groups such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecanyl, tetracyclododecanylmethyl, and dicyclohexylmethyl groups; unsaturated hydrocarbyl groups such as allyl and 3-cyclohexenyl groups; aryl groups such as phenyl, 1-naphthyl, and 2-naphthyl groups; and aralkyl groups such as benzyl and diphenylmethyl groups.

[0143] In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the group containing a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. Examples of hydrocarbyl groups containing heteroatoms include a tetrahydrofuryl group, a methoxymethyl group, an ethoxymethyl group, a methylthiomethyl group, an acetamidomethyl group, a trifluoroethyl group, a (2-methoxyethoxy)methyl group, an acetoxymethyl group, a 2-carboxy-1-cyclohexyl group, a 2-oxopropyl group, a 4-oxo-1-adamantyl group, and a 3-oxocyclohexyl group.

[0144] The synthesis of sulfonium salts containing anions represented by the above general formula (1A') is described in detail in JP-A-2007-145797, JP-A-2008-106045, JP-A-2009-7327, JP-A-2009-258695, etc. In addition, sulfonium salts described in JP-A-2010-215608, JP-A-2012-41320, JP-A-2012-106986, JP-A-2012-153644, etc. are also preferably used.

[0145] Examples of the anion represented by the above general formula (1A) include the same anions as those exemplified as the anion represented by formula (1A) in JP2018-197853A.

[0146] In the above general formula (1B), R fb1 and R fb2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 107 Examples of the same as those given in the explanation of R fb1 and Rfb2 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 means that the groups (-CF2-SO2-N - -SO2-CF2-) may form a ring, in which case, R fb1 and R fb2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0147] In the above general formula (1C), R fc1 , R fc2 and R fc3 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 107 Examples of the same as those given in the explanation of R fc1 , R fc2 and R fc3 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 means that the groups (-CF2-SO2-C - -SO2-CF2-) may form a ring, in which case, R fc1 and R fc2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0148] In the above general formula (1D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 107 Examples of the examples are similar to those given in the description of .

[0149] The synthesis of a sulfonium salt containing an anion represented by the above general formula (1D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

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

[0151] Although the photoacid generator containing the anion represented by the above general formula (1D) does not have a fluorine atom at the α-position of the sulfo group, it has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave the acid labile group in the base polymer, and can therefore be used as a photoacid generator.

[0152] Furthermore, as the photoacid generator, a compound represented by the following general formula (2) can also be suitably used. [ka]

[0153] In the above general formula (2), R 201 and R 202 R is each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 201 and R 202 or R 201 and R 203 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring may be any of the rings described above in the description of general formula (10-1) as R 101 and R 102 and the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0154] R 201 and R 202The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, 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]. 2,6 cyclic saturated hydrocarbyl groups such as a decanyl group and an adamantyl group; and aryl groups such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, a tert-butylnaphthyl group, and an anthracenyl group. In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, these groups may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, and the like.

[0155] R 203The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups such as methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, and heptadecane-1,17-diyl; cyclopentanediyl, cyclohexanediyl, and cyclohexanediyl. Examples of the alkyl group include cyclic saturated hydrocarbylene groups such as a hexanediyl group, a norbornanediyl group, and an adamantanediyl group; and arylene groups such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group, an isobutylphenylene group, a sec-butylphenylene group, a tert-butylphenylene group, a naphthylene group, a methylnaphthylene group, an ethylnaphthylene group, an n-propylnaphthylene group, an isopropylnaphthylene group, an n-butylnaphthylene group, an isobutylnaphthylene group, a sec-butylnaphthylene group, and a tert-butylnaphthylene group. In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., so that they may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. As the heteroatom, an oxygen atom is preferable.

[0156] In the above general formula (2), L 1 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a single bond, an ether bond, or a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R203 Examples of the hydrocarbylene group represented by the formula (I) include the same as those exemplified above.

[0157] In the above general formula (2), X A , X B , X C and X D are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. A , X B , X C and X D At least one of the groups is a fluorine atom or a trifluoromethyl group.

[0158] In the above general formula (2), k is an integer of 0 to 3.

[0159] As the photoacid generator represented by the above general formula (2), one represented by the following general formula (2') is preferable. [ka]

[0160] In the above general formula (2'), L 1 is the same as above. R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 are each independently a 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. Specific examples thereof include R 107 Examples of the cations are the same as those exemplified in the explanation of 1. Each of x and y is independently an integer of 0 to 5, and z is an integer of 0 to 4.

[0161] Examples of the photoacid generator represented by the above general formula (2) include the same as those exemplified as the photoacid generator represented by formula (2) in JP2017-026980A.

[0162] Among the above photoacid generators, those containing an anion represented by the above general formula (1A') or (1D) are particularly preferred because of their small acid diffusion and excellent solubility in resist solvents. Also, those represented by the above general formula (2') are particularly preferred because of their extremely small acid diffusion.

[0163] Furthermore, as the photoacid generator, a sulfonium salt or an iodonium salt having an anion containing an aromatic ring substituted with an iodine atom or a bromine atom can be used. Examples of such salts include those represented by the following general formula (3-1) or (3-2). [ka]

[0164] In the above general formulas (3-1) and (3-2), p is an integer satisfying 1≦p≦3. q and r are integers satisfying 1≦q≦5, 0≦r≦3, and 1≦q+r≦5. q is preferably an integer satisfying 1≦q≦3, more preferably 2 or 3. r is preferably an integer satisfying 0≦r≦2.

[0165] In the above general formulas (3-1) and (3-2), X BI represents an iodine atom or a bromine atom, and when q is 2 or more, they may be the same or different.

[0166] In the above general formulas (3-1) and (3-2), L 11 is a single bond, an ether bond or an ester bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched or cyclic.

[0167] In the above general formulas (3-1) and (3-2), L 12represents a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and represents a trivalent or tetravalent linking group having 1 to 20 carbon atoms when p is 2 or 3, and the linking group may contain an oxygen atom, a sulfur atom, a nitrogen atom, a chlorine atom, a bromine atom or an iodine atom.

[0168] In the above general formulas (3-1) and (3-2), R 401 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 10 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group, or an ether bond, or -NR 401A -C(=O)-R 401B or -NR 401A -C(=O)-OR 401B R 401A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 401B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbyloxycarbonyl group, saturated hydrocarbylcarbonyl group, and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 may be the same or different from each other.

[0169] Of these, R 401 Examples include hydroxyl groups, -NR 401A -C(=O)-R 401B , -NR 401A -C(=O)-OR 401B , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group, and the like are preferred.

[0170] In the above general formulas (3-1) and (3-2), Rf 11 ~Rf 14 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, at least one of which is a fluorine atom or a trifluoromethyl group. 11 and Rf 12 may combine to form a carbonyl group. 13 and Rf 14 are preferably both fluorine atoms.

[0171] In the above general formulas (3-1) and (3-2), R 402 , R 403 , R 404 , R 405 and R 406 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 101 ~R 105 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. In addition, some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the carbon atoms of these groups may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate group, or a sulfonate ester bond. 402 and R 403may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is as defined in the above general formula (10-1) as R 101 and R 102 and the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0172] Examples of the cation of the sulfonium salt represented by the above general formula (3-1) include the same as those exemplified as the cation of the sulfonium salt represented by the above general formula (10-1). Examples of the cation of the iodonium salt represented by the above general formula (3-2) include the same as those exemplified as the cation of the iodonium salt represented by the above general formula (10-2).

[0173] Examples of the anion of the onium salt represented by the above general formula (3-1) or (3-2) include, but are not limited to, those shown below. In the following formula, X BI is the same as above.

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] [ka]

[0178] [ka]

[0179]

change

[0180]

change

[0181]

change

[0182]

change

[0183]

change

[0184]

change

[0185]

change

[0186]

change

[0187]

change

[0188]

change

[0189]

change

[0190] [ka]

[0191] [ka]

[0192] [ka]

[0193] [ka]

[0194] [ka]

[0195] [ka]

[0196] [ka]

[0197] In the positive resist material of the present invention, the content of the additive acid generator 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. By including the repeating units a1 and / or a2 in the base polymer, and optionally including an additive acid generator, the positive resist material of the present invention can function as a chemically amplified positive resist material.

[0198] [Organic solvents] The positive resist material of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the above-mentioned base polymer, the sulfonium salt quencher, the additive acid generator if included, and each component described below. Examples of such organic solvents include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] to

[0145] of JP-A-2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol monoethyl ether. Examples of suitable solvents include ethers such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, etc.; 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, propylene glycol mono-tert-butyl ether acetate, etc.; lactones such as γ-butyrolactone, etc.; and mixed solvents of these.

[0199] In the positive resist composition of the present invention, the content of the organic solvent is preferably from 100 to 10,000 parts by mass, and more preferably from 200 to 8,000 parts by mass, per 100 parts by mass of the base polymer.

[0200] [Quencher] The positive resist material of the present invention may contain a quencher other than the quencher of the sulfonium salt of fluoroalcohol. Examples of the quencher include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, and the like. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonic acid ester bond, or compounds having a carbamate group described in JP Patent Publication No. 3790649, are preferred. By adding such a basic compound, for example, it is possible to further suppress the diffusion rate of the acid in the resist film and to correct the shape.

[0201] Further, the above-mentioned quencher includes onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids not fluorinated at the α-position, as described in JP-A-2008-158339. Sulfonic acids, imide acids, or methide acids fluorinated at the α-position are necessary for deprotecting acid labile groups of carboxylic acid esters, but the sulfonic acids or carboxylic acids not fluorinated at the α-position are released by salt exchange with onium salts not fluorinated at the α-position. Sulfonic acids and carboxylic acids not fluorinated at the α-position do not cause a deprotection reaction, and therefore function as quenchers.

[0202] Examples of such quenchers include compounds represented by the following general formula (4) (onium salts of sulfonic acids not fluorinated at the α-position) and compounds represented by the following general formula (5) (onium salts of carboxylic acids). [ka]

[0203] In the above general formula (4), R 501 represents a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group.

[0204] The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-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]. 2,6 Examples of the alkenyl group include alkenyl groups such as vinyl, allyl, propenyl, butenyl, and hexenyl groups; cyclic unsaturated aliphatic hydrocarbyl groups such as cyclohexenyl groups; aryl groups such as phenyl, naphthyl, alkylphenyl groups (2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, and 4-n-butylphenyl groups), dialkylphenyl groups (2,4-dimethylphenyl, 2,4,6-triisopropylphenyl, and the like), alkylnaphthyl groups (methylnaphthyl, ethylnaphthyl, and the like), and dialkylnaphthyl groups (dimethylnaphthyl, diethylnaphthyl, and the like); heteroaryl groups such as thienyl groups; and aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl groups.

[0205] In addition, a portion of the hydrogen atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and a portion of the carbon atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, these groups may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like. Examples of hydrocarbyl groups containing heteroatoms include alkoxyphenyl groups such as 4-hydroxyphenyl group, 4-methoxyphenyl group, 3-methoxyphenyl group, 2-methoxyphenyl group, 4-ethoxyphenyl group, 4-tert-butoxyphenyl group, and 3-tert-butoxyphenyl group; alkoxynaphthyl groups such as methoxynaphthyl group, ethoxynaphthyl group, n-propoxynaphthyl group, and n-butoxynaphthyl group; dialkoxynaphthyl groups such as dimethoxynaphthyl group and diethoxynaphthyl group; and aryloxoalkyl groups such as 2-aryl-2-oxoethyl group, 2-(1-naphthyl)-2-oxoethyl group, and 2-(2-naphthyl)-2-oxoethyl group.

[0206] In the above general formula (5), R 502 R is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. 502 The hydrocarbyl group represented by R 501 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. Other specific examples include fluorine-containing alkyl groups such as trifluoromethyl group, trifluoroethyl group, 2,2,2-trifluoro-1-methyl-1-hydroxyethyl group, and 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl group; and fluorine-containing aryl groups such as pentafluorophenyl group and 4-trifluoromethylphenyl group. + is an onium cation.

[0207] As the quencher, a sulfonium salt of an iodized benzene ring-containing carboxylic acid represented by the following general formula (6) can also be suitably used. [ka]

[0208] In the above general formula (6), R 601 represents a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which some or all of the hydrogen atoms may be substituted with halogen atoms, or -NR 601A -C(=O)-R 601B or -NR 601A -C(=O)-OR 601B R 601A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 601B is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms.

[0209] In the above general formula (6), x' is an integer of 1 to 5. y' is an integer of 0 to 3. z' is an integer of 1 to 3. L 21 is a single bond or a (z'+1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate group, a halogen atom, a hydroxy group, and a carboxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When y' is 2 or more, each R 601 may be the same or different from each other.

[0210] In the above general formula (6), R 602 , R 603 and R 604are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. In addition, some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, an oxo group, a cyano group, a nitro group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the carbon atoms of these groups may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate group, or a sulfonate ester bond. In addition, R 602 and R 603 may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0211] Specific examples of the compound represented by the above general formula (6) include those described in JP 2017-219836 A. Iodine atoms have high absorption of EUV light with a wavelength of 13.5 nm, which generates secondary electrons during exposure, and the energy of the secondary electrons is transferred to the acid generator, accelerating the decomposition of the quencher, thereby improving the sensitivity.

[0212] As the quencher, a polymer-type quencher described in JP-A-2008-239918 can also be used. This enhances the rectangularity of the resist after patterning by orienting on the resist surface after coating. The polymer-type quencher also has the effect of preventing film loss of the pattern and rounding of the pattern top when a protective film for immersion exposure is applied.

[0213] In the positive resist composition of the present invention, the content of the quencher is preferably from 0 to 5 parts by mass, and more preferably from 0 to 4 parts by mass, relative to 100 parts by mass of the base polymer. The quenchers may be used alone or in combination of two or more.

[0214] [Other ingredients] In addition to the above-mentioned components, surfactants, dissolution inhibitors, etc. can be appropriately combined and blended according to the purpose to form a positive resist material, and the base polymer in the exposed area is accelerated in dissolution rate in the developer by catalytic reaction, so that a positive resist material with extremely high sensitivity can be obtained. In this case, the resist film has high dissolution contrast and resolution, has exposure margin, is excellent in process adaptability, and has a good pattern shape after exposure, while the dimensional difference between coarse and fine is small because acid diffusion can be suppressed, and therefore it is highly practical and can be very effective as a resist material for VLSI.

[0215] Examples of the surfactant include those described in paragraphs

[0165] to

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

[0216] By adding a dissolution inhibitor, the difference in dissolution rate between exposed and unexposed areas can be further increased, and the resolution can be further improved. The dissolution inhibitor includes a compound having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule, in which the hydrogen atoms of the phenolic hydroxyl groups are substituted with acid labile groups at a ratio of 0 to 100 mol % as a whole, or a compound having a carboxyl group in the molecule, in which the hydrogen atoms of the carboxyl groups are substituted with acid labile groups at an average ratio of 50 to 100 mol % as a whole. Specific examples include bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalene carboxylic acid, adamantane carboxylic acid, and hydroxyl groups of cholic acid, and compounds in which hydrogen atoms of carboxyl groups are substituted with acid labile groups, and the like, which are described in, for example, paragraphs

[0155] to

[0178] of JP-A-2008-122932.

[0217] The content of the dissolution inhibitor is preferably 0 to 50 parts by mass, and more preferably 5 to 40 parts by mass, relative to 100 parts by mass of the base polymer. The dissolution inhibitors may be used alone or in combination of two or more.

[0218] The positive resist material of the present invention may be blended with a water repellency improver for improving the water repellency of the resist surface after spin coating. The water repellency improver can be used in immersion lithography without using a topcoat. As the water repellency improver, a polymer compound containing a fluorinated alkyl group, a polymer compound containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue of a specific structure, and the like are preferred, and those exemplified in JP-A-2007-297590, JP-A-2008-111103, and the like are more preferred. The water repellency improver needs to be dissolved in an alkaline developer or an organic solvent developer. The water repellency improver having the specific 1,1,1,3,3,3-hexafluoro-2-propanol residue described above has good solubility in the developer. As a water repellency improver, a polymer compound containing a repeating unit containing an amino group or an amine salt is highly effective in preventing the evaporation of the acid in the PEB and preventing the opening of the hole pattern after development.

[0219] In the positive resist composition of the present invention, the content of the water repellency improver is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the base polymer. The water repellency improvers can be used alone or in combination of two or more kinds.

[0220] The positive resist composition of the present invention may contain acetylene alcohols. Examples of the acetylene alcohols include those described in paragraphs

[0179] to

[0182] of JP 2008-122932 A. The content of the acetylene alcohols in the positive resist composition of the present invention is preferably 0 to 5 parts by mass per 100 parts by mass of the base polymer.

[0221] [Pattern formation method] When the positive resist material of the present invention is used in various integrated circuit manufacturing, known lithography techniques can be applied.For example, the pattern forming method includes the steps of forming a resist film on a substrate using the above-mentioned resist material, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0222] First, the positive resist material of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., so that the coating film thickness is 0.01 to 2 μm. This is pre-baked on a hot plate, preferably at 60 to 150 ° C., for 10 seconds to 30 minutes, more preferably at 80 to 120 ° C., for 30 seconds to 20 minutes, to form a resist film.

[0223] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far-ultraviolet radiation, EB, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. When ultraviolet radiation, far-ultraviolet radiation, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. are used as the high-energy radiation, the exposure dose is preferably 1 to 200 mJ / cm2, either directly or using a mask for forming a desired pattern. 2 Approximately, more preferably 10 to 100 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 100 μC / cm 2 Approximately, more preferably 0.5 to 50 μC / cm 2 The positive resist material of the present invention is suitable for fine patterning using high energy rays, particularly i-rays with a wavelength of 365 nm, KrF excimer laser light, ArF excimer laser light, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, γ-rays, and synchrotron radiation, and is particularly suitable for fine patterning using EB or EUV.

[0224] After the exposure, PEB may be performed on a hot plate or in an oven, preferably at 50 to 150° C. for 10 seconds to 30 minutes, more preferably at 60 to 120° C. for 30 seconds to 20 minutes.

[0225] After exposure or PEB, development is carried out using a developer of an alkaline aqueous solution such as 0.1 to 10 mass %, preferably 2 to 5 mass %, of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), or the like for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by a conventional method such as a dip method, a puddle method, a spray method, or the like. The irradiated areas are dissolved in the developer, while the unexposed areas are not dissolved, and the desired positive pattern is formed on the substrate.

[0226] Using the above-mentioned positive resist material, negative development can also be carried out to obtain a negative pattern by organic solvent development.The developer used at this time can be 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, Examples of the organic solvent include methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents can be used alone or in combination of two or more.

[0227] At the end of the development, rinsing is performed. As the rinsing liquid, a solvent that is miscible with the developer and does not dissolve the resist film is preferable. As such a solvent, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms are preferably used.

[0228] Specific examples of alcohols having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, and 3-hexanol. , 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.

[0229] Examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, and di-n-hexyl ether.

[0230] Examples of alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Examples of alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Examples of alkynes having 6 to 12 carbon atoms include hexine, heptine, octyne, etc.

[0231] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0232] Rinsing can reduce the occurrence of resist pattern collapse and defects. Rinsing is not always necessary, and not performing rinsing can reduce the amount of solvent used.

[0233] The developed hole pattern or trench pattern can also be shrunk by thermal flow, RELACS technology, or DSA technology. A shrink agent is applied onto the hole pattern, and the shrink agent crosslinks on the surface of the resist due to diffusion of an acid catalyst from the resist layer during baking, and the shrink agent adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, and excess shrink agent is removed to shrink the hole pattern. EXAMPLES

[0234] The present invention will be specifically described below with reference to Synthesis Examples, Comparative Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples.

[0235] [Synthesis Example 1-1] Synthesis of Quencher Q-1 [ka] After mixing 9.4g of nonafluoro-tert-butoxy alcohol and 10g of pure water, 6.4g of 25% aqueous sodium hydroxide solution was added dropwise under ice cooling. After stirring for 1 hour under ice cooling, 11.2g of triphenylsulfonium methyl sulfate and 85g of methylene chloride were added and stirred for 15 minutes. The organic layer was separated and washed 7 times with 20g of pure water. The obtained organic layer was concentrated under reduced pressure at 35°C to 9.3g, 50g of tert-butyl methyl ether was added and stirred for 20 minutes to precipitate a solid. The solid was filtered and washed with tert-butyl methyl ether, and the powder was dried under reduced pressure at 20°C to obtain 4.7g of the target triphenylsulfonium nonafluoro-tert-butoxide (yield 31%).

[0236] The spectral data of the obtained target substance are shown below. Nuclear magnetic resonance spectrum ( 1 H-NMR, 19 The results of F-NMR / DMSO-d6) are shown in Figures 1 and 2. 1 H-NMR showed traces of residual solvent (water) and the added internal standard (2,3,5,6-tetrafluoro-p-xylene). 19 The added internal standard substance (2,3,5,6-tetrafluoro-p-xylene) was also observed in F-NMR.

[0237] IR(D-ATR):ν=3351,3224,3101,3064,3045,3004,1664,1581,1480,1448,1250,1193,1126,1066,997,952,754,720,686,530,507,492cm -1

[0238] Time-of-flight mass spectrometry (TOFMS; MALDI) POSITIVE M + 263.1 (C 18 H 15 S + equivalent) NEGATIVE M - 235.0 (C4F9O - equivalent)

[0239] [Synthesis Examples 1-2 to 1-19, Comparative Synthesis Examples 1-1 to 1-3] Quenchers Q-2 to Q-19 and comparative quenchers cQ-1 to cQ-3 were synthesized by a similar ion exchange method.

[0240] [ka]

[0241] [ka]

[0242] [ka]

[0243] [Synthesis Examples 2-1 to 2-14, Comparative Synthesis Example 2-1] Synthesis of base polymers (polymers 1 to 14, comparative polymer 1) Each monomer was combined and copolymerized in THF, which was a solvent, crystallized in methanol, and then repeatedly washed with hexane, isolated and dried to obtain base polymers (polymers 1 to 14, comparative polymer 1) with the compositions shown below. The compositions of the obtained base polymers were as follows: 1 Mw and Mw / Mn were confirmed by H-NMR and GPC (solvent: THF, standard: polystyrene).

[0244] [ka]

[0245] [ka]

[0246] [ka]

[0247] [ka]

[0248] [ka]

[0249] [Examples 1 to 32, Comparative Examples 1 to 5] (1) Preparation of positive resist material A positive resist material was prepared by filtering a solution of each component in the composition shown in Tables 1 and 2 in a solvent containing 50 ppm of Omnova's surfactant Polyfox 636 through a 0.2 μm filter.

[0250] In Tables 1 and 2, the components are as follows: Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (Diacetone Alcohol) EL (Ethyl lactate)

[0251] Acid generator: PAG1 (see structural formula below) [ka]

[0252] Water repellent polymer 1 (see structural formula below) [ka]

[0253] (2) EUV lithography evaluation Each resist material shown in Tables 1 and 2 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a thickness of 20 nm, and the resist film was pre-baked at 105°C for 60 seconds using a hot plate to produce a resist film with a thickness of 35 nm. This was exposed using an EUV scanner NXE3400 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, 90-degree dipole illumination, a mask with a line-and-space 1:1 pattern with a pitch of 32 nm on the wafer), and PEB was performed on a hot plate at the temperatures shown in Tables 1 and 2 for 60 seconds, and development was performed for 30 seconds with a 2.38% by mass TMAH aqueous solution to obtain a line-and-space pattern with a line dimension of 16 nm.

[0254] The exposure dose when the line dimension was formed at 16 nm was measured and this was taken as the sensitivity. In addition, edge roughness was measured using a Hitachi High-Technologies Corporation length measuring SEM (CG6300), and the window was calculated by subtracting the dimension at which the resist pattern collapses or the film is reduced at an exposure dose greater than the resist sensitivity from the line dimension at which the space portion can be resolved at an exposure dose less than the resist sensitivity. The results are shown in Tables 1 and 2.

[0255] [Table 1] [Table 2]

[0256] The results shown in Tables 1 and 2 show that the positive resist material containing an acid generator that is a sulfonium salt of sulfonic acid bound to the polymer main chain and a quencher that is a sulfonium salt of a fluoroalcohol with a specific structure had high sensitivity, good LWR, and a wide window.

[0257] On the other hand, Comparative Examples 1 to 3 and 5, which do not contain a sulfonium salt of a fluoroalcohol having a specific structure, had a large LWR and a particularly narrow window. Comparative Example 4, which contains a sulfonium salt of a fluoroalcohol having a specific structure but does not contain an acid generator of a sulfonium salt of a sulfonic acid bonded to the polymer main chain, had a wide window but a large LWR.

[0258] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and any embodiment that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

1. A positive resist material comprising an acid generator which is a sulfonium salt of a sulfonic acid ion bonded to a polymer main chain, and a quencher which is a sulfonium salt represented by the following general formula (1): 【Chemistry 1】 (In the formula, R １ is a fluorine atom, a phenyl group, a phenyloxycarbonyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkynyl group having 2 to 4 carbon atoms, or an alkoxycarbonyl group having 1 to 20 carbon atoms, and a part or all of the hydrogen atoms of the alkyl group, alkoxy group, alkenyl group, alkynyl group, and alkoxycarbonyl group are each independently selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, a R may be substituted with one or more groups selected from a cyano group, a nitro group, a phenyl group, and a hydroxy group, or may have an ester group, an ether group, or a sulfonyl group, and some or all of the hydrogen atoms of the phenyl group and the phenyloxycarbonyl group may be substituted with one or more groups selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a fluorinated alkyl group having 1 to 4 carbon atoms, a fluorinated alkyloxy group having 1 to 4 carbon atoms, a trifluoromethylthio group, a cyano group, a nitro group, and a hydroxy group. ２ ~R ４ are each independently a halogen atom or a hydrocarbyl group having 1 to 25 carbon atoms, and the hydrocarbyl group may have at least one atom selected from an oxygen atom, a sulfur atom, a nitrogen atom, and a halogen atom. ２ and R ３ and, or R ２ and R ４ and may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

2. 2. The positive resist material according to claim 1, wherein the acid generator bonded to the polymer main chain is contained in a base polymer that includes a repeating unit represented by the following general formula (a1) and / or (a2): 【Chemistry 2】 (In the formula, R Ａ are each independently a hydrogen atom or a methyl group. １ is a single bond, an ester bond, or a phenylene group. ２ is a single bond, -Z ２１ -C(=O)-O-, -Z ２１ -O- or -Z ２１ -O-C(=O)-. Z ２１ Z is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, a sulfur atom, an oxygen atom, a bromine atom, or an iodine atom. ３ is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, a hydrocarbon group having 2 to 4 carbon atoms which may be substituted with fluorine, or a carbonyl group. ４ represents a fluorinated phenylene group, a trifluoromethyl group or a phenylene group substituted with an iodine atom; ４１ -, -O-Z ４１ -, -C(=O)-O-Z ４１ - or -C(=O)-NH-Z ４１ - is. ４１ R is a hydrocarbylene group which may contain a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group or an iodine atom, an ester group having 1 to 15 carbon atoms substituted with a halogen atom, and / or an aromatic hydrocarbon group. ５ ~R ７ are each independently a hydrocarbyl group having 1 to 25 carbon atoms, and may have an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom other than fluorine. ５ and R ６ and, or R ５ and R ７ and may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

3. 3. The positive resist material according to claim 2, wherein the base polymer comprises a repeating unit in which a hydrogen atom of a carboxy group represented by the following general formula (b1) is substituted with an acid labile group and / or a repeating unit in which a hydrogen atom of a phenolic hydroxy group represented by the following general formula (b2) is substituted with an acid labile group: 【Chemistry 3】 (In the formula, R Ａ Each of Y is independently a hydrogen atom or a methyl group. １ Y is a linking group having 1 to 15 carbon atoms and containing at least one bond selected from a single bond, a phenylene group, a naphthylene group, an ester bond, an ether bond, and a lactone ring. ２ is a single bond, an ester bond or an amide bond. ３ R is a single bond, an ether bond or an ester bond. １１ , R １２ is an acid labile group. １３ R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. １４ is a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of whose carbon atoms may be substituted with ether bonds or ester bonds; a is 1 or 2; and b is an integer of 0 to 4, with the proviso that 1≦a+b≦5.

4. The positive resist material according to claim 2 or 3, characterized in that the base polymer further contains a repeating unit containing an adhesive group selected from the group consisting of a hydroxy group, a carboxy group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonate ester bond, a cyano group, an amide bond, -O-C(=O)-S- and -O-C(=O)-NH-.

5. 5. The positive resist material according to claim 1, further comprising at least one of an acid generator other than the acid generator for the sulfonium salt, an organic solvent, a quencher other than the quencher for the sulfonium salt, and a surfactant.

6. 6. A pattern forming method comprising the steps of: forming a resist film on a substrate using the positive resist material according to claim 1; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

7. 7. The pattern formation method according to claim 6, wherein the high energy beam is i-beam, KrF excimer laser beam, ArF excimer laser beam, electron beam or extreme ultraviolet ray having a wavelength of 3 to 15 nm.

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