Resist composition and pattern forming method

Abstract

The present invention provides a polymerizable composition comprising: (A) a base polymer containing a repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring and a repeating unit having a phenolic hydroxy group; (B) a polymeric compound represented by general formula (1); [Formula 1] TIFF0007805537000195.tif33137(R B is a hydrogen atom, etc., Ra is a trifluoromethyl group, etc., R B1 , R B2 is an alkyl group, etc. B3 is an alkyl group, which may be substituted with a fluorine atom. 1 ~X 4 is -C(=O)- etc. R B4 is an alkylene group having a cyclic structure, etc., R B6 , R B5 is an alkyl group or the like. n1 is 1 or 2. The following conditions are satisfied: 0<(a-1)<1, 0<(b-1)<1, 0≦(b-2)<1, 0≦(b-3)<1. ) A resist composition comprising (C) a photoacid generator, (D) an acid diffusion controller, and (E) a solvent. This provides a resist composition that exhibits high sensitivity and high resolution, minimizes edge roughness and dimensional variation, and provides a favorable pattern shape and defect reduction after exposure.

Description

[Technical Field]

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

[0002] In recent years, with the increasing integration and speed of LSIs, there has been a demand for finer pattern rules and higher-resolution resist patterns. As a result, there is an increasing need to improve not only lithography characteristics such as pattern shape, contrast, Mask Error Factor (MEF), Depth of Focus (DOF), and Line Width Roughness (LWR), but also defects in the resist pattern after development.

[0003] In particular, as patterns become finer, line width roughness (LWR) of line patterns and dimensional uniformity (CDU) of hole patterns become problematic. The effects of uneven distribution and aggregation of base polymers and acid generators, as well as the effects of acid diffusion, have been pointed out. Furthermore, as resist films become thinner, LWR tends to increase, and the deterioration of LWR due to thinning accompanying the progress of miniaturization has become a serious problem.

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

[0005] Because iodine atoms have a very high absorption rate for EUV light with a wavelength of 13.5 nm, the effect of generating secondary electrons from iodine atoms during exposure has been confirmed, and this has attracted attention in EUV lithography. Patent Documents 1 and 2 describe photoacid generators and acid diffusion inhibitors in which iodine atoms are introduced into the anion, while Patent Documents 3 and 4 describe photoacid generators and acid diffusion inhibitors in which iodine atoms are introduced into the cation. While these have been confirmed to improve lithography performance to a certain extent, iodine atoms are not highly soluble in organic solvents, and there are concerns about the risk of precipitation in the solvent and pattern defects.

[0006] In order to overcome the trade-off between sensitivity and LWR, structural optimization of photoacid generators and weak acid onium salt-type acid diffusion inhibitors has been investigated. For example, Patent Documents 5, 6, and 7 discuss onium salt-type acid diffusion control agents with aromatic rings in the anion moiety, but they have yet to develop resist materials that satisfy both sensitivity, LWR, and CDU. Furthermore, improving defects is also an urgent issue. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6720926 [Patent Document 2] Patent No. 6702264 [Patent Document 3] Patent No. 7140075 [Patent Document 4] Patent No. 7099418 [Patent Document 5] Patent No. 6702264 [Patent Document 6] Patent No. 7517106 [Patent Document 7] JP 2024-113847 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resist composition and a pattern formation method that have higher sensitivity and higher resolution than conventional positive resist compositions, and that have small edge roughness and dimensional variation, and that are excellent in pattern shape and defect reduction after exposure. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides: (A) a base polymer containing at least one repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring and at least one repeating unit having a phenolic hydroxy group; (B) a polymer compound having a repeating unit represented by the following general formula (1): [ka] (In the formula, R B are independently a hydrogen atom or a methyl group. Ra is a methyl group or a trifluoromethyl group. R B1 , R B2 are independently hydrogen atoms (except R B1 and R B2 and R are hydrogen atoms, or a linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms, and R B1 and R B2 may be bonded to form a ring, in which case R B1 and R B2 R represents a divalent organic group having a total of 2 to 4 carbon atoms. B3 is a linear, branched, or cyclic alkyl group, in which some or all of the hydrogen atoms may be substituted with fluorine atoms, and which may contain an iminosulfonyl group. 1 , X 2 , X 3 , X 4 are independently -C(=O)-, -C(=O)-O-, -C(=O)-OR B7 -, -O-, -C(=O)-R B7 -C(=O)- and -C(=O)-OR B7-C(=O)-O-. R B7 R is a linear, branched, or cyclic alkylene group having 1 to 10 carbon atoms. B4 is an alkylene group or alkanetriyl group having a cyclic structure and having 4 to 12 carbon atoms, which may be substituted with fluorine; R B5 is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, which may be substituted with fluorine; R B4 and R B5 may be bonded to form a ring having 3 to 12 carbon atoms. B6 is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, which may be substituted with fluorine. n1 is 1 or 2. a-1, b-1, b-2, and b-3 satisfy the ranges 0<(a-1)<1, 0<(b-1)<1, 0≦(b-2)<1, 0≦(b-3)<1, and 0<(a-1)+(b-1)+(b-2)+(b-3)≦1. (C) a photoacid generator, (D) an acid diffusion controller, and (E) Solvent and the component (D) is contained in an amount of 11 to 50 parts by mass per 100 parts by mass of the component (A).

[0010] This makes it possible to provide a resist composition that has higher sensitivity and higher resolution than conventional positive resist materials, has less edge roughness and dimensional variation, and is excellent in pattern shape and defect reduction after exposure.

[0011] Furthermore, the component (A) preferably contains a polymer whose solubility in a developer is changed by the action of acid, the polymer including a repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring, represented by the following formula (A1), a repeating unit having a phenolic hydroxy group, and a repeating unit that generates acid upon exposure, represented by any of the following formulae (C1) to (C4). [ka] (In the formula, R Ais a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z A is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OZ A1 -, and the phenylene group and naphthylene group may be substituted with a halogen atom, a methoxy group, or a trifluoromethoxy group. A1 is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or naphthylene group. * represents a bond to a carbon atom in the main chain. R C and R D are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, and R C and R D may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 1 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms. R 2 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. n1 is an integer of 1 or 2. n2 is an integer of 0 to 5. n3 is an integer of 0 to 2. [ka] (In the formula, R A is the same as above. Z 1 is a single bond or a phenylene group. Z 2 is *-C(=O)-OZ 21 -, *-C(=O)-NH-Z 21 -or*-OZ 21 -It is. Z 21 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 3 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OZ 31 -It is. Z 31 is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group. Z 4 is a single bond or *-Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. Z 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-C(=O)-OZ 51 -, *-C(=O)-N(H)-Z 51 -or*-OZ 51 -It is. Z 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. * denotes a carbon atom in the main chain, Z 1 , or Z 3 Represents a bond with . R 21 and R 22 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond or a carbamate bond. Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. Rf 3 and Rf 4are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms, provided that all Rf 5 and Rf 6 cannot simultaneously become a hydrogen atom. M - is a non-nucleophilic counterion. A + is an onium cation. c is an integer from 0 to 3.

[0012] With such component (A), the effects of the present invention can be more fully exhibited.

[0013] The resist composition of the present invention may further contain a surfactant in addition to the component (B).

[0014] In the present invention, a surfactant can be used in combination, if necessary.

[0015] The present invention also provides a pattern forming method, comprising the steps of: forming a resist film on a substrate using the resist composition; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

[0016] In this way, it is possible to provide a pattern formation method that has higher sensitivity and higher resolution than conventional positive resist materials, has less edge roughness and dimensional variation, and is excellent in pattern shape and defects after exposure.

[0017] The high-energy beam is preferably i-ray, KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light having a wavelength of 3 to 15 nm.

[0018] In the present invention, such high energy rays can be suitably used.

[0019] In the pattern forming method of the present invention, an aqueous alkaline solution is used as the developer to dissolve exposed areas, thereby obtaining a positive pattern in which unexposed areas do not dissolve.

[0020] Alternatively, an organic solvent can be used as the developer to dissolve the unexposed areas, thereby obtaining a negative pattern in which the exposed areas do not dissolve.

[0021] The resist composition of the present invention can be used in both positive and negative pattern formation methods. [Effects of the Invention]

[0022] As described above, the present invention is capable of providing a resist composition and a pattern formation method that have higher sensitivity and higher resolution than conventional positive resist compositions, with reduced edge roughness and dimensional variation, and with a favorable pattern shape and reduced defects after exposure. DETAILED DESCRIPTION OF THE INVENTION

[0023] As described above, there has been a need for the development of a resist composition and a pattern formation method that have higher sensitivity and higher resolution than conventional positive resist materials, have small edge roughness and dimensional variation, and are favorable in terms of pattern shape and defects after exposure.

[0024] The present inventors have conducted extensive research to develop a positive resist with the high resolution and low line roughness (LWR) and constant dimension variation (CDU) required in recent years. As a result, they have found that it is effective to use a resist composition containing (A) a base polymer containing at least one repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring and at least one repeating unit having a phenolic hydroxy group, (B) a specific polymeric compound functioning as a surfactant, (C) a photoacid generator, (D) an acid diffusion controller, and (E) a solvent. Furthermore, they have found that it is preferable to minimize the acid diffusion distance and to uniform the acid concentration in the resist film in the exposed areas, and that this can be achieved by using a polymer containing a sulfonium salt or iodonium salt of a carboxylic acid and a sulfonium salt or iodonium salt of a sulfonic acid as repeating units.

[0025] Furthermore, the present inventors have found that, in order to improve dissolution contrast, introduction of a repeating unit in which the hydrogen atom of a carboxyl group or a phenolic hydroxyl group is substituted with an acid labile group, and introduction of a fluoroalcohol-containing polymer compound, results in a resist composition that has high sensitivity, a significantly high alkali dissolution rate contrast before and after exposure, high sensitivity, a high acid diffusion suppression effect, high resolution, and small and good pattern shape, edge roughness, and dimensional variation after exposure, and is particularly suitable as a fine pattern forming material for use in the manufacture of VLSIs or photomasks, and have completed the present invention.

[0026] That is, the present invention provides: (A) a base polymer containing at least one repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring and at least one repeating unit having a phenolic hydroxy group; (B) a polymer compound having a repeating unit represented by the following general formula (1): [ka] (In the formula, R B are independently a hydrogen atom or a methyl group. Ra is a methyl group or a trifluoromethyl group. RB1 , R B2 are independently hydrogen atoms (except R B1 and R B2 and R are hydrogen atoms, or a linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms, and R B1 and R B2 may be bonded to form a ring, in which case R B1 and R B2 R represents a divalent organic group having a total of 2 to 4 carbon atoms. B3 is a linear, branched, or cyclic alkyl group, in which some or all of the hydrogen atoms may be substituted with fluorine atoms, and which may contain an iminosulfonyl group. 1 , X 2 , X 3 , X 4 are independently -C(=O)-, -C(=O)-O-, -C(=O)-OR B7 -, -O-, -C(=O)-R B7 -C(=O)- and -C(=O)-OR B7 -C(=O)-O-. R B7 R is a linear, branched, or cyclic alkylene group having 1 to 10 carbon atoms. B4 is an alkylene group or alkanetriyl group having a cyclic structure and having 4 to 12 carbon atoms, which may be substituted with fluorine; R B5 is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, which may be substituted with fluorine; R B4 and R B5 may be bonded to form a ring having 3 to 12 carbon atoms. B6 is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, which may be substituted with fluorine. n1 is 1 or 2. a-1, b-1, b-2, and b-3 satisfy the ranges 0<(a-1)<1, 0<(b-1)<1, 0≦(b-2)<1, 0≦(b-3)<1, and 0<(a-1)+(b-1)+(b-2)+(b-3)≦1. (C) a photoacid generator, (D) an acid diffusion controller, and (E) Solvent and the component (D) is contained in an amount of 11 to 50 parts by mass per 100 parts by mass of the component (A).

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

[0028] [(A) Base polymer] The resist composition of the present invention is characterized by comprising a base polymer that contains at least one repeating unit having an acid labile group that contains a fluorine atom-containing aromatic ring, and at least one repeating unit having a phenolic hydroxy group.

[0029] [Repeating units having an acid labile group containing a fluorine atom-containing aromatic ring] The base polymer in the present invention contains a repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring (hereinafter also referred to as repeating unit A). Such a repeating unit is preferably represented by the following formula (A1).

[0030] [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z A is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OZ A1 -, and the phenylene group and naphthylene group may be substituted with a halogen atom, a methoxy group, or a trifluoromethoxy group. A1 is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or naphthylene group. * represents a bond to a carbon atom in the main chain. R C and R D are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, and R C and R Dmay be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 1 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms. R 2 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. n1 is an integer of 1 or 2. n2 is an integer of 0 to 5. n3 is an integer of 0 to 2.

[0031] Examples of the repeating unit A include, but are not limited to, those shown below. In the following formula, R A is the same as above.

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] [ka]

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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[0047]

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[0048] The acid-labile group in which a carboxylic acid is protected by tertiary benzyl alcohol has a significantly lower activation energy for the acid-catalyzed deprotection reaction than the acid-labile group of a tertiary alkyl group, such as a tert-butyl group, and the deprotection reaction proceeds even at temperatures around 50°C. When a polymer with an acid-labile group with a deprotection reaction activation energy that is too low is used as the base polymer, the post-exposure bake (PEB) temperature becomes too low, making it difficult to control the temperature uniformity and to control the acid diffusion. If the acid diffusion distance cannot be controlled, the CDU and limiting resolution of the developed pattern will decrease. To control the acid diffusion, an appropriate PEB temperature is required; a temperature range of 75–120°C is generally appropriate.

[0049] Another problem with using low activation energy protecting groups is that when a photoacid generator (PAG) is copolymerized into the polymer, the protecting group may be removed during polymerization. While onium salt PAGs are essentially neutral, heating during polymerization can cause partial dissociation of the onium salt. Also, when repeating units containing phenolic hydroxyl groups are copolymerized simultaneously, an exchange reaction between the protons of the phenolic hydroxyl groups and the cations of the PAG can occur, generating acid and causing deprotection of the protecting group. This deprotection during polymerization is particularly pronounced when low activation energy protecting groups are used.

[0050] As mentioned above, acid-labile groups in which carboxylic acids are protected with tertiary benzyl alcohol have the advantage of being highly resistant to etching due to the presence of a benzene ring. However, when PAG is copolymerized, elimination occurs during polymerization. Attaching an electron-withdrawing group to the benzene ring increases the activation energy for deprotection. This is thought to be because the electron-withdrawing group reduces the stability of the benzyl cation, the intermediate in deprotection. Attaching an electron-withdrawing group to a protecting group that is very easy to deprotect can reduce the reactivity of the deprotection reaction and optimize it.

[0051] Fluorine atoms have a high absorption rate for EUV (13.5 nm), which is said to have a sensitizing effect that improves sensitivity. Introducing fluorine atoms into protecting groups is expected to improve sensitivity. However, when fluorine atoms are introduced into the acid-labile group of a tertiary alkyl group, the electron-withdrawing effect of fluorine significantly reduces the stability of the intermediate cation in the deprotection reaction, preventing the formation of olefins and preventing the deprotection reaction. However, tertiary acid-labile groups with fluorine-containing aromatic groups have optimal stability of the intermediate cation and exhibit moderate deprotection reactivity.

[0052] As described above, by using the base polymer as the base polymer of a chemically amplified positive resist composition in order to suppress acid diffusion and improve dissolution contrast and etching resistance, the alkaline dissolution rate contrast before and after exposure is significantly higher, the acid diffusion suppression effect is high, high resolution is achieved, and the pattern shape and LWR after exposure are favorable, and furthermore, excellent etching resistance is exhibited.

[0053] The resist composition (chemically amplified resist composition) of the present invention, in particular, exhibits high dissolution contrast of the resist film due to an optimal deprotection reaction, a high effect of suppressing acid diffusion, high resolution, exposure latitude, excellent process adaptability, a good pattern shape after exposure, and superior etching resistance. Therefore, due to these excellent properties, it is highly practical and extremely effective as a material for forming a mask pattern.

[0054] [Repeating units having a phenolic hydroxy group] The base polymer of the present invention contains a repeating unit having a phenolic hydroxy group (hereinafter also referred to as repeating unit B). As repeating unit B, one represented by the following formula (B1) is preferred.

[0055] [ka]

[0056] In formula (B1), R A is the same as above. Z B is a single bond or *-C(=O)-O-. * represents a bond to a carbon atom in the main chain. R 11 is a halogen atom, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may contain a heteroatom. m1 is an integer of 1 to 4. m2 is an integer of 0 to 4, provided that 1≦m1+m2≦5.

[0057] R 11 The hydrocarbyl group represented by the formula (A1) and the hydrocarbyl moiety of the hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbylcarbonyloxy group and hydrocarbyloxycarbonyl group may be saturated or unsaturated, and may be linear, branched or cyclic. C and R D Examples of the hydrocarbyl group represented by the formula include those shown in the chemical structural formula showing specific examples of the repeating unit A.

[0058] Examples of the repeating unit B include, but are not limited to, those shown below. In the following formula, R A is the same as above.

[0059] [ka]

[0060] [ka]

[0061] [ka]

[0062] [Repeating unit that generates acid upon exposure] The base polymer may contain a repeating unit that generates acid upon exposure (hereinafter also referred to as repeating unit C). The repeating unit C is a repeating unit represented by the following formula (C1) (hereinafter also referred to as repeating unit C1), a repeating unit represented by the following formula (C2) (hereinafter also referred to as repeating unit C2), a repeating unit represented by the following formula (C3) (hereinafter also referred to as repeating unit C3), or a repeating unit represented by the following formula (C4) (hereinafter also referred to as repeating unit C4).

[0063] [ka]

[0064] In formulas (C1) to (C4), R A is the same as above. Z 1 is a single bond or a phenylene group. 2 is *-C(=O)-OZ 21 -, *-C(=O)-NH-Z 21 -or*-OZ 21 -It is. Z 21 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 3 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OZ 31 -It is. Z 31 Z is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group. 4 is a single bond or *-Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 5represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-C(=O)-OZ 51 -, *-C(=O)-N(H)-Z 51 -or*-OZ 51 -It is. Z 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. * represents a carbon atom in the main chain, Z 1 , or Z 3 Represents a bond with .

[0065] Z 21 , Z 31 and Z 51 The aliphatic hydrocarbylene group represented by the formula (A1) may be linear, branched, or cyclic. A1 Examples of the repeating unit A include those shown in the chemical structural formulas showing specific examples of the repeating unit A.

[0066] Z 41 The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include, but are not limited to, those shown below.

[0067] [ka] (In the formula, the dashed lines represent bonds.)

[0068] In formula (C1), R 21 and R 22are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; saturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; unsaturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these, with aryl groups being preferred. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0069] Also, R 21 and R 22 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Specific examples include those represented by the following formula. In the following formula, the dashed line indicates Z. 2 Represents a bond with .

[0070] [ka]

[0071] Examples of the cation of the repeating unit represented by formula (C1) include, but are not limited to, the following: A is the same as above.

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] In formula (C1), M -is a non-nucleophilic counter ion. Examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion; fluoroalkylsulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion and nonafluorobutanesulfonate ion; arylsulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion and 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as mesylate ion and butanesulfonate ion; imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion and bis(perfluorobutylsulfonyl)imide ion; and methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0080] Further examples of the non-nucleophilic counter ion include a sulfonate anion represented by the following formula (C1-1) in which the α-position is substituted with a fluorine atom, and a sulfonate anion represented by the following formula (C1-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group.

[0081] [ka]

[0082] In formula (C1-1), R 23is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 30 carbon atoms, or a hydrocarbyloxycarbonyl group having 2 to 30 carbon atoms, and may contain a halogen atom, an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbylcarbonyloxy group and hydrocarbyloxycarbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group, a nonyl group, an undecyl group, a tridecyl group, a pentadecyl group, a heptadecyl group, and an icosanyl group; a cyclopentyl group, a cyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, a 1-adamantylmethyl group, and a norbornyl group. C3-38 saturated cyclic hydrocarbyl groups such as norbornylmethyl, tricyclodecanyl, tetracyclododecanyl, tetracyclododecanylmethyl, and dicyclohexylmethyl; C2-38 unsaturated aliphatic hydrocarbyl groups such as allyl and 3-cyclohexenyl; C6-38 aryl groups such as phenyl, 1-naphthyl, and 2-naphthyl; C7-38 aralkyl groups such as benzyl and diphenylmethyl; and groups obtained by combining these. 23An aliphatic group is preferred as the hydrocarbyl group. Some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, or some of the -CH2- groups in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. Examples of hydrocarbyl groups containing hetero atoms include tetrahydrofuryl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, and 3-oxocyclohexyl groups.

[0083] In formula (C1-2), R 24 R is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and may contain a halogen atom, an ether bond, an ester bond, a carbonyl group, or a lactone ring. 25 is a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. The hydrocarbyl moiety of the hydrocarbyl group and the hydrocarbyl carbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 23 Examples of the hydrocarbyl group represented by R include the same as those exemplified above. 25 As the aryl group, a trifluoromethyl group is preferred.

[0084] Specific examples of the sulfonate anion represented by formula (C1-1) or (C1-2) include, but are not limited to, the following: 25 is the same as above, and Ac is an acetyl group.

[0085]

change

[0086]

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[0087]

change

[0088]

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[0089]

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[0090]

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[0091]

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[0092]

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[0093]

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[0094]

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[0095]

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[0096] In formulas (C2) and (C3), L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond, or a carbamate bond. Among these, from the viewpoint of synthesis, an ether bond, an ester bond, or a carbonyl group is preferred, and an ester bond or a carbonyl group is more preferred.

[0097] In formula (C2), Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 1 and Rf 2 In order to increase the acid strength of the generated acid, it is preferable that Rf be a fluorine atom. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. Of these, Rf 3 and Rf 4 At least one of these is preferably a trifluoromethyl group.

[0098] In formula (C3), Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms, provided that all Rf 5 and Rf 6 cannot be simultaneously hydrogen atoms. Among these, Rf 5 and Rf 6 At least one of these is preferably a trifluoromethyl group.

[0099] In the formulae (C2) and (C3), c is an integer of 0 to 3, with 1 being preferred.

[0100] Examples of the anion of the repeating unit represented by formula (C2) include, but are not limited to, those shown below. Ais the same as above.

[0101] [ka]

[0102] [ka]

[0103] [ka]

[0104] [ka]

[0105] [ka]

[0106] [ka]

[0107] [ka]

[0108] Examples of the anion of the repeating unit represented by formula (C3) include, but are not limited to, those shown below. A is the same as above.

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] Examples of the anion of the repeating unit represented by formula (C4) include, but are not limited to, those shown below. A is the same as above.

[0113] [ka]

[0114] In formulas (C2) to (C4), A + is an onium cation. Examples of the onium cation include an ammonium cation, a sulfonium cation, and an iodonium cation, and the onium cation is preferably a sulfonium cation or an iodonium cation, and more preferably a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2).

[0115] [ka]

[0116] In formulas (cation-1) and (cation-2), R ct1 ~R ct5are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; saturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; unsaturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these, with aryl groups being preferred. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0117] Also, R ct1 and R ct2 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, examples of the sulfonium cation represented by formula (cation-1) include those represented by the following formula:

[0118] [ka] (In the formula, the dashed line indicates R ct3)

[0119] Examples of the sulfonium cation represented by formula (cation-1) include, but are not limited to, those shown below.

[0120] [ka]

[0121] [ka]

[0122] [ka]

[0123] [ka]

[0124] [ka]

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] [ka]

[0129]

change

[0130]

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[0131]

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[0132]

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[0133]

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[0134]

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[0135]

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[0136]

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[0137]

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[0138]

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[0139]

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[0140] [ka]

[0141] Examples of the iodonium cation represented by formula (cation-2) include, but are not limited to, those shown below.

[0142] [ka]

[0143] Specific structures of the repeating units represented by formulae (C1) to (C4) include any combination of the above-mentioned anions and cations.

[0144] As the repeating unit C, repeating units C2, C3 and C4 are preferred from the viewpoint of controlling acid diffusion, repeating units C2 and C4 are more preferred from the viewpoint of the acid strength of the generated acid, and repeating unit C2 is more preferred from the viewpoint of solvent solubility.

[0145] The polymer in the resist composition of the present invention is characterized by containing a repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring, a repeating unit having a phenolic hydroxy group, and a repeating unit that generates an acid upon exposure. Upon exposure, secondary electrons are generated from the repeating unit having the phenolic hydroxy group. The secondary electrons are effectively transmitted to the cation at the acid-generating site, resulting in decomposition of the sulfonium cation or iodonium cation, generating the corresponding acid. The generated acid is bound to the polymer backbone, preventing excessive acid diffusion. Furthermore, the repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring forms a stable tertiary benzyl cation after elimination. Tertiary benzyl cations are more stable than carbocations eliminated from typical tertiary ester-type acid labile groups and are therefore more reactive with acid. This results in a high dissolution contrast in the developer and improved sensitivity of the resist film. Furthermore, the introduction of an acid labile group containing a fluorine atom-containing aromatic ring increases the fluorine atom concentration in the polymer, thereby improving solubility in solvents and resulting in uniform dissolution and reduced aggregation of polymer chains. It is believed that the synergistic effect of these three repeating units enables the formation of patterns with high sensitivity and high contrast, and excellent LWR for line patterns and CDU for hole patterns.

[0146] The base polymer may further contain at least one repeating unit selected from the repeating units represented by the following formulas (a1) (hereinafter also referred to as repeating unit a1) and (a2) (hereinafter also referred to as repeating unit a2):

[0147] [ka]

[0148] In formulas (a1) and (a2), R A is the same as above. Z C is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OZ C1 -, the phenylene group and naphthylene group may have a substituent, and Z C1Z is a saturated hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond, a thioether, a sulfonamide, a sulfonate ester or a lactone ring, or a phenylene group or a naphthylene group. D is a single bond, *-C(=O)-O- or *-C(=O)-OZ C1 - and Z C1 is the same as above. * represents a bond to a carbon atom in the main chain. R 12 X is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom, a cyano group, or a heteroatom. A and X B are each independently an acid labile group not containing a fluorine-containing aromatic ring, and k is an integer of 0 to 4.

[0149] In formulas (a1) and (a2), X A and X B Examples of the acid labile group represented by the formula (I) include those described in JP-A Nos. 2013-80033 and 2013-83821.

[0150] Typical examples of the acid labile group include those represented by the following formulae (AL-1) to (AL-3).

[0151] [ka] (In the formula, the dashed lines represent bonds.)

[0152] In formulas (AL-1) and (AL-2), R L1 and R L2 are each independently a saturated hydrocarbyl group having 1 to 40 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The saturated hydrocarbyl group may be linear, branched, or cyclic. The saturated hydrocarbyl group preferably has 1 to 20 carbon atoms.

[0153] In formula (AL-1), a is an integer of 0 to 10, and an integer of 1 to 5 is preferred.

[0154] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms, and may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be linear, branched, or cyclic. L2 , R L3 and R L4 Any two of these may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0155] In formula (AL-3), R L5 , R L6 and R L7 are each independently a saturated 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 linear, branched, or cyclic. L5 , R L6 and R L7 Any two of these may be bonded to each other together with the carbon atoms to which they are bonded to form a ring having 3 to 20 carbon atoms. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0156] Examples of the repeating unit a1 include, but are not limited to, those shown below. A and X A is the same as above.

[0157] [ka]

[0158] [ka]

[0159] [Chemical formula]

[0160] Examples of the repeating unit a2 include, but are not limited to, those shown below. In the following formula, R A and X B are the same as described above.

[0161] [Chemical formula]

[0162] The base polymer of component (A) particularly preferably contains a repeating unit having an acid-labile group containing a fluorine atom-containing aromatic ring represented by the above formula (A1), a repeating unit having a phenolic hydroxy group, and a repeating unit that generates an acid upon exposure and is represented by any of the above formulas (C1) to (C4), and contains a polymer whose solubility in a developer changes by the action of an acid.

[0163] In the (A) base polymer, the content ratios of the repeating units A, B, C, a1, and a2 are 0 < A < 1.0, 0 < B < 1.0, 0 ≤ C < 1.0, 0 ≤ a1 < 1.0, and 0 ≤ a2 < 1.0, preferably 0 < A < 1.0, 0 < B < 1.0, 0 < C < 1.0, 0 ≤ a1 < 1.0, and 0 ≤ a2 < 1.0, and more preferably 0.25 < A < 0.85, 0.1 < B < 0.7, 0.05 < C < 0.65, 0 ≤ a1 < 0.6, and 0 ≤ a2 < 0.6. When the repeating unit C is at least one selected from the repeating units C1 to C4, C = C1 + C2 + C3 + C4. Also, A + B + C + a1 + a2 ≤ 1.

[0164] The weight-average molecular weight (Mw) of the (A) base polymer is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. When Mw is within this range, sufficient etching resistance is obtained, and there is no risk of a decrease in resolution due to an inability to ensure a difference in dissolution rate before and after exposure. In the present invention, Mw is a value measured in terms of polystyrene by gel permeation chromatography (GPC) using THF or N,N-dimethylformamide (DMF) as a solvent.

[0165] Furthermore, if the molecular weight distribution (Mw / Mn) of the polymer is broad, low-molecular-weight and high-molecular-weight polymers will be present, which may result in the appearance of foreign matter on the pattern or deterioration of the pattern shape after exposure. Therefore, as the pattern rule becomes finer, the influence of Mw / Mn tends to become greater, so in order to obtain a resist composition that is suitable for use with fine pattern dimensions, it is preferable that the Mw / Mn of the polymer has a narrow distribution of 1.0 to 2.0.

[0166] To synthesize the polymer, for example, a monomer that provides the repeating unit described above may be polymerized by heating in an organic solvent with the addition of a radical polymerization initiator.

[0167] Examples of organic solvents used during polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyrolactone (GBL). Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of these initiators added is preferably 0.01 to 25 mol% based on the total amount of monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the viewpoint of production efficiency.

[0168] The polymerization initiator may be added to the monomer solution and then fed to the reaction vessel. Alternatively, an initiator solution may be prepared separately from the monomer solution and then fed to the reaction vessel independently. From the perspective of quality control, it is preferable to prepare the monomer solution and the initiator solution independently and then add them dropwise, since radicals generated from the initiator during the waiting time may cause the polymerization reaction to proceed, resulting in the formation of ultra-high molecular weight polymers. The acid labile group may be used as is after being introduced into the monomer, or may be protected or partially protected after polymerization. Furthermore, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol may be used in combination to adjust the molecular weight. In this case, the amount of the chain transfer agent added is preferably 0.01 to 20 mol % of the total amount of monomers to be polymerized.

[0169] In the case of a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group, such as an ethoxyethoxy group, which is easily deprotected by an acid, during polymerization, and then deprotected with a weak acid and water after polymerization. Alternatively, the hydroxy group may be substituted with an acetyl group, a formyl group, a pivaloyl group, or the like, and then subjected to alkaline hydrolysis after polymerization.

[0170] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers may be polymerized by heating in an organic solvent with the addition of a radical polymerization initiator. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene may be used, and after polymerization, the acetoxy group may be deprotected by alkaline hydrolysis to form polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0171] The base that can be used in alkaline hydrolysis includes aqueous ammonia, triethylamine, etc. The reaction temperature is preferably −20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0172] The amount of each monomer in the monomer solution may be appropriately set so as to achieve the preferred content ratio of the repeating units described above.

[0173] The polymer obtained by the above-mentioned production method may be a reaction solution obtained by a polymerization reaction as a final product, or a powder obtained through a purification process such as a reprecipitation method in which the polymerization solution is added to a poor solvent to obtain a powder, and the resulting product may be handled as a final product. However, from the viewpoint of work efficiency and quality stability, it is preferable to handle a polymer solution obtained by dissolving the powder obtained by the purification process in a solvent as a final product. Specific examples of solvents to be used in this case include ketones such as cyclohexanone and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether, as described in paragraphs

[0144] and

[0145] of JP-A-2008-111103. esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono tert-butyl ether acetate; lactones such as GBL; keto alcohols such as diacetone alcohol (DAA); high-boiling alcohol solvents such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol; and mixed solvents thereof.

[0174] The concentration of the polymer in the polymer solution is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0175] The reaction solution and polymer solution are preferably filtered through a filter, which is effective in stabilizing quality by removing foreign matter and gels that may cause defects.

[0176] Examples of filter materials used in the filter filtration include fluorocarbon, cellulose, nylon, polyester, and hydrocarbon-based materials. However, in the filtration process of resist compositions, filters made of fluorocarbons, such as Teflon (registered trademark), hydrocarbons such as polyethylene and polypropylene, or nylon are preferred. The pore size of the filter can be selected appropriately depending on the target cleanliness, but is preferably 100 nm or less, more preferably 20 nm or less. These filters may be used alone or in combination. The filtration method may involve passing the solution through the filter only once, but it is more preferable to circulate the solution and perform multiple filtrations. The filtration process can be performed in any order and any number of times in the polymer production process. However, it is preferable to filter the reaction solution after the polymerization reaction, the polymer solution, or both.

[0177] The polymer may contain two or more polymers having different composition ratios, Mw, and molecular weight distributions.

[0178] [(B) Polymer compound] The resist composition of the present invention also contains a polymeric compound having a repeating unit represented by the following general formula (1).

[0179] Surfactants that are insoluble or slightly soluble in water but soluble in an alkaline developer are useful because they become soluble during alkaline aqueous solution development after exposure or PEB and are unlikely to become foreign matter that could cause defects. Such surfactants are insoluble or slightly soluble in water but soluble in an alkaline developer, and are polymer-type surfactants (polymer compounds), also known as hydrophobic resins, and are particularly preferred because they have high water repellency and improve water sliding properties.

[0180] Such polymer compounds include polymer compounds having a repeating unit represented by the following general formula (1).

[0181] [ka] (In the formula, R B are independently a hydrogen atom or a methyl group. Ra is a methyl group or a trifluoromethyl group. R B1 , R B2 are independently hydrogen atoms (except R B1 and R B2 and R are hydrogen atoms, or a linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms, and R B1 and R B2 may be bonded to form a ring, in which case R B1 and R B2 R represents a divalent organic group having a total of 2 to 4 carbon atoms. B3 is a linear, branched, or cyclic alkyl group, in which some or all of the hydrogen atoms may be substituted with fluorine atoms, and which may contain an iminosulfonyl group. 1 , X 2 , X 3 , X 4 are independently -C(=O)-, -C(=O)-O-, -C(=O)-OR B7 -, -O-, -C(=O)-R B7 -C(=O)- and -C(=O)-OR B7 -C(=O)-O-. R B7 R is a linear, branched, or cyclic alkylene group having 1 to 10 carbon atoms. B4 is an alkylene group or alkanetriyl group having a cyclic structure and having 4 to 12 carbon atoms, which may be substituted with fluorine; R B5 is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, which may be substituted with fluorine; R B4 and R B5 may be bonded to form a ring having 3 to 12 carbon atoms. B6 is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, which may be substituted with fluorine. n1 is 1 or 2. a-1, b-1, b-2, and b-3 satisfy the ranges 0<(a-1)<1, 0<(b-1)<1, 0≦(b-2)<1, 0≦(b-3)<1, and 0<(a-1)+(b-1)+(b-2)+(b-3)≦1.

[0182] RB3 The number of carbon atoms in the linear, branched, or cyclic alkyl group is not particularly limited, but may be, for example, 1 to 50 carbon atoms, preferably 1 to 30 carbon atoms, and more preferably 1 to 20 carbon atoms.

[0183] Examples of the repeating unit represented by general formula (1) include, but are not limited to, those shown below. B is the same as above.

[0184] Examples of the repeating unit a-1 include the following:

[0185] [ka]

[0186] Examples of the repeating unit b-1 include the following:

[0187] [ka]

[0188] [ka]

[0189] [ka]

[0190] [ka]

[0191] [ka]

[0192] [ka]

[0193] Examples of the repeating unit b-2 include the following: [ka]

[0194] Examples of the repeating unit b-3 include the following: [ka]

[0195] The polymer compound may further contain other repeating units in addition to the repeating unit represented by formula (1). Examples of other repeating units include repeating units obtained from methacrylic acid and α-trifluoromethylacrylic acid derivatives. The content of the repeating unit represented by formula (1) in the polymer compound is preferably 20 mol % or more, more preferably 60 mol % or more, and even more preferably 100 mol % of all repeating units.

[0196] The ratio of repeating units a-1, b-1, b-2, and b-3 is 0<(a-1)<1, 0<(b-1)<1, 0≦(b-2)<1, 0≦(b-3)<1, or 0<(a-1)+(b-1)+(b-2)+(b-3)≦1, preferably 0.2<(a-1)<0.9, 0.1<(b-1)<0.8, 0≦(b-2)<1, or 0≦(b-3)<1, and more preferably 0.4<(a-1)<0.9, 0.1<(b-1)<0.6, 0≦(b-2)<1, or 0≦(b-3)<1.

[0197] The Mw of the polymer compound is preferably from 1,000 to 500,000, and more preferably from 3,000 to 100,000. The Mw / Mn is preferably from 1.0 to 2.5, and more preferably from 1.0 to 1.6.

[0198] The polymer compound can be synthesized by heating a monomer containing an unsaturated bond that provides the repeating unit represented by formula (1) and, if necessary, other repeating units in an organic solvent with the addition of a radical initiator to polymerize the monomer. Examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, and dioxane. Examples of polymerization initiators include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. The acid labile group introduced into the monomer may be used as is, or may be protected or partially protected after polymerization.

[0199] When synthesizing the polymer compound, a known chain transfer agent such as dodecyl mercaptan or 2-mercaptoethanol may be used to adjust the molecular weight. In this case, the amount of the chain transfer agent added is preferably 0.01 to 10 mol % based on the total number of moles of the monomers to be polymerized.

[0200] In the resist composition of the present invention, the content of the (B) polymeric compound is not particularly limited, but is, for example, 0.1 to 100 parts by mass, and preferably 1 to 10 parts by mass, per 100 parts by mass of the (A) base polymer. The (B) polymeric compound may be used alone or in combination of two or more types.

[0201] [(C) Photoacid generator] The resist composition of the present invention contains a photoacid generator (hereinafter referred to as an additive-type acid generator) that generates a strong acid. The strong acid here refers to a compound that has sufficient acidity to cause a deprotection reaction of the acid labile groups of the base polymer.

[0202] The acid generator may be a compound (photoacid generator) that generates an acid in response to actinic rays or radiation. The photoacid generator may be any compound that generates an acid upon exposure to high-energy rays, but is preferably one that generates a sulfonic acid, an imide acid, or a methide acid. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators. Specific examples of the acid generator include those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A.

[0203] Furthermore, the photoacid generator is preferably an onium salt represented by the following formula (2).

[0204] [ka]

[0205] In formula (2), A + is an onium cation. Examples include, but are not limited to, those mentioned above.

[0206] In formula (2), Xa - is an anion selected from the following formulae (2A) to (2D).

[0207] [ka]

[0208] In formula (2A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (2A') described below. 111 Examples include those similar to those exemplified in the explanation of .

[0209] The anion represented by formula (2A) is preferably one represented by the following formula (2A').

[0210] [ka]

[0211] In formula (2A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0212] In formula (2A'), R 111 is a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom or a halogen atom, and more preferably an oxygen atom. In order to obtain high resolution in the formation of a fine pattern, the hydrocarbyl group is preferably one having 6 to 30 carbon atoms.

[0213] R 111 The hydrocarbyl group having 1 to 30 carbon atoms and represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group, a nonyl group, an undecyl group, a tridecyl group, a pentadecyl group, a heptadecyl group, and an icosyl group; a cyclopentyl group, a cyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, a 1-adamantylmethyl group, and a norbornyl group. cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms such as a norbornylmethyl group, a tricyclodecanyl group, a tetracyclododecanyl group, a tetracyclododecanylmethyl group, or a dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 30 carbon atoms such as an allyl group or a 3-cyclohexenyl group; aryl groups having 6 to 30 carbon atoms such as a phenyl group, a 1-naphthyl group, or a 2-naphthyl group; aralkyl groups having 7 to 30 carbon atoms such as a benzyl group or a diphenylmethyl group; and groups obtained by combining these.

[0214] In addition, some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH- in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the hydrocarbyl group containing a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. The heteroatom is preferably an oxygen atom. Examples of hydrocarbyl groups containing hetero atoms include tetrahydrofuryl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, and 3-oxocyclohexyl groups.

[0215] The synthesis of sulfonium salts containing anions represented by formula (2A') is described in detail in JP-A Nos. 2007-145797, 2008-106045, 2009-7327, and 2009-258695. Sulfonium salts described in JP-A Nos. 2010-215608, 2012-41320, 2012-106986, and 2012-153644 are also suitable.

[0216] Examples of the anion represented by formula (2A) include, but are not limited to, those shown below: In the following formula, Ac is an acetyl group.

[0217] [ka]

[0218] [ka]

[0219] [ka]

[0220] In formula (2B), 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. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by R include the same as those exemplified above. fb1 and R fb2 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 are bonded to each other and form the bonded group (-CF2-SO2-N - -SO2-CF2-) together to form a ring, in which case, R fb1 and R fb2 The group obtained by bonding these groups together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0221] In formula (2C), 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. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by R include the same as those exemplified above. fc1 , R fc2 and R fc3 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 are bonded to each other and form the bonded group (-CF2-SO2-C - -SO2-CF2-) together to form a ring, in which case, R fc1 and R fc2 The group obtained by bonding these groups together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0222] In formula (2D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0223] The synthesis of sulfonium salts containing anions represented by formula (2D) is described in detail in JP-A-2010-215608.

[0224] Examples of the anion represented by formula (2D) include, but are not limited to, those shown below.

[0225] [ka]

[0226] Although the photoacid generator containing the anion represented by formula (2D) does not have a fluorine atom at the α-position of the sulfo group, it has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave the acid labile groups in the base polymer, making it suitable for use as a photoacid generator.

[0227] Among the above photoacid generators, those containing an anion represented by formula (2A') or (2D) are particularly preferred because they have small acid diffusion and excellent solubility in solvents.

[0228] In the resist composition of the present invention, the content of the photoacid generator (C) is preferably 0.1 to 200 parts by mass, more preferably 0.1 to 100 parts by mass, per 100 parts by mass of the base polymer (A). The photoacid generator (C) may be used alone or in combination of two or more types.

[0229] [(D) Acid diffusion inhibitor] The resist composition of the present invention contains (D) an acid diffusion inhibitor. Because the acid generated after quenching a strong acid has a relatively high acidity, when such an acid diffusion inhibitor is used in combination with a highly reactive acid labile group unit, the acid generated after quenching accelerates the elimination reaction, albeit slightly, leading to improved contrast and, as a result, improved lithography performance.

[0230] Suitable onium salt acid diffusion inhibitors are those represented by the following formulas (1-I) to (4-I).

[0231] [ka] (In formula (1-I), n1 is an integer of 0 to 5. m is an integer of 0 to 4. L is a single bond, an ether bond, or an ester bond. When n is 2 or more, each L may be the same or different. R 1A represents a hydroxy group, or a linear, branched, or cyclic alkyl or alkoxy group having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be substituted with halogen atoms, a linear, branched, or cyclic acyloxy group having 2 to 6 carbon atoms, or a linear, branched, or cyclic alkylsulfonyloxy group having 1 to 4 carbon atoms, or a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, -NR 1B -C(=O)-R 1C , or -NR 1B -C(=O)-OR 1C and R 1B is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, and R 1C R is a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, or a linear, branched, or cyclic alkenyl group having 2 to 8 carbon atoms. 2A represents a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 10 carbon atoms, and a hydrogen atom in the hydrocarbyl group may be substituted with a halogen atom, and -CH2- in the hydrocarbyl group may be substituted with an ether bond or a carbonyl group. In formula (2-I), n2 is an integer of 1 to 5. m is an integer of 0 to 4. R 1F is an alkyl group or a fluorinated alkyl group having 6 to 18 carbon atoms, and -CH2- in the alkyl group may be substituted with an ether bond or a carbonyl group. 1F has at least one linear structure having 6 or more carbon atoms. When n2 is 2 or more, each R 1F may be the same or different. The alkyl group may contain, as a partial structure, a ring structure selected from a cyclopentane ring, a cyclohexane ring, an adamantane ring, and a norbornyl ring at the terminal or between the carbon-carbon bonds. L and R 2A is the same as above. In formula (3-I), R 1 and R 2 are each independently a hydrogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 12 carbon atoms, and a hydrogen atom in the hydrocarbyl group may be substituted with a heteroatom-containing group, and -CH2- in the hydrocarbyl group may be substituted with -O- or -C(=O)-. 1 and R 2 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R f1 and R f2 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, provided that at least one of them is a fluorine atom or a trifluoromethyl group. L 1 represents a single bond or a hydrocarbylene group having 1 to 15 carbon atoms, and a hydrogen atom in the hydrocarbylene group may be substituted with a heteroatom-containing group, and -CH2- in the hydrocarbylene group may be substituted with -O- or -C(=O)-. L 2 is a single bond, an ether bond or an ester bond. Ar is an aromatic group having 3 to 15 carbon atoms and a valence of (n3+1), and some or all of the hydrogen atoms of the aromatic group may be substituted with a substituent. n3 is an integer that satisfies 1≦n3≦5. In formula (4-I), R 1’ and R 2’ each independently represent a halogen atom other than iodine, a hydroxy group, an amino group, a nitro group, a cyano group, or a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 15 carbon atoms which may contain a halogen atom, a hydroxy group, a nitro group, a cyano group, or a heteroatom, and a methylene group in the hydrocarbon group may be replaced with an ether bond (-O-) or a carbonyl group (-CO-). L a and L b is a single bond, an ether bond, an ester bond, a sulfonate ester bond or a carbonate bond. L 1’ represents a linear, branched, or cyclic divalent hydrocarbon group having 4 to 12 carbon atoms, in which a hydrogen atom may be substituted with a halogen atom, a hydroxy group, a nitro group, or a cyano group, and a methylene group in the hydrocarbon group may be substituted with an ether bond (-O-) or a carbonyl group (-CO-). L 2’ is a single bond, an ether bond, an ester bond or a carbonate bond. L 3’ is a single bond or a hydrocarbylene group having 1 to 15 carbon atoms which may contain a hetero atom. n4 and n5 are 0 or 1. n6 represents an integer of 0 to 4 when n4=0, and represents an integer of 0 to 6 when n4=1. n7 represents an integer of 0 to 3 when n5=0, and represents an integer of 0 to 5 when n5=1. x represents an integer of 1 to 5 when n4=0, and represents an integer of 1 to 7 when n4=1. y represents an integer of 1 to 4 when n5=0, and an integer of 1 to 6 when n5=1. n6, n7, x, and y are integers that satisfy 1≦n6+x≦5 when n4=0, 1≦n6+x≦7 when n4=1, 1≦n7+y≦4 when n5=0, and 1≦n7+y≦6 when n5=1. If n6≧2, multiple R 1 may be the same or different, and when n7≧2, multiple R2 may be the same or different. In the formula, A + is an onium cation, including but not limited to those mentioned above.

[0232] Specific examples of the anion of the salt compound represented by formula (1-I) include, but are not limited to, those shown below.

[0233] [ka]

[0234] [ka]

[0235] [ka]

[0236] [ka]

[0237] Specific examples of the anion of the salt compound represented by formula (2-I) include, but are not limited to, those shown below.

[0238] [ka]

[0239] [ka]

[0240] [ka]

[0241] Examples of the anion of the salt compound represented by formula (3-I) include, but are not limited to, those shown below: In the following formula, Me is a methyl group.

[0242] [ka]

[0243] [ka]

[0244] [ka]

[0245] [ka]

[0246] [ka]

[0247] [ka]

[0248] [ka]

[0249] [ka]

[0250] [ka]

[0251] [ka]

[0252] [ka]

[0253] [ka]

[0254] Examples of the anion of the salt compound represented by formula (4-I) include, but are not limited to, those shown below: In the following formula, Me is a methyl group.

[0255] [ka]

[0256] [ka]

[0257] [ka]

[0258] [ka]

[0259] [ka]

[0260] [ka]

[0261] [ka]

[0262]

change

[0263]

change

[0264]

change

[0265]

change

[0266]

change

[0267]

change

[0268]

change

[0269]

change

[0270]

change

[0271]

change

[0272]

change

[0273]

change

[0274]

change

[0275]

change

[0276]

change

[0277]

change

[0278]

change

[0279]

change

[0280]

change

[0281]

change

[0282]

change

[0283]

change

[0284]

change

[0285]

change

[0286]

change

[0287]

change

[0288]

change

[0289]

change

[0290]

change

[0291]

change

[0292]

change

[0293]

change

[0294] [ka]

[0295] [ka]

[0296] [ka]

[0297] Specific structures of the onium salt compound of the present invention include combinations of the specific anions and the specific cations described above.

[0298] The content of the (D) acid diffusion inhibitor in the resist composition of the present invention is 11 to 50 parts by mass, and more preferably 20 or more parts by mass, per 100 parts by mass of the (A) base polymer. Within this range, the resolution is good, and the LWR is particularly excellent. These onium salt compounds can be used alone or in combination of two or more.

[0299] [Nitrogen-containing quencher] The resist composition of the present invention may further contain a nitrogen-containing quencher. Examples of nitrogen-containing quenchers include primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond. Other examples include compounds in which a primary or secondary amine is protected with a carbamate group, such as the compounds described in JP 3790649 A.

[0300] Alternatively, a sulfonate sulfonium salt having a nitrogen-containing substituent may be used as a nitrogen-containing quencher. Such a compound functions as a quencher in unexposed areas and loses its quenching ability in exposed areas by neutralizing with the acid generated by the compound itself, functioning as a so-called photodegradable base. The use of a photodegradable base can further enhance the contrast between exposed and unexposed areas. For example, JP-A Nos. 2009-109595 and 2012-46501 can be used as references for the photodegradable base.

[0301] When the resist composition of the present invention contains a nitrogen-containing quencher, the content thereof is preferably 0.001 to 12 parts by mass, and more preferably 0.01 to 8 parts by mass, relative to 100 parts by mass of the (A) base polymer. The nitrogen-containing quencher may be used alone or in combination of two or more types.

[0302] [Surfactants] The resist composition of the present invention may further contain a surfactant in addition to the component (B). The surfactant is preferably a surfactant that is insoluble or slightly soluble in water but soluble in an alkaline developer, or a surfactant that is insoluble or slightly soluble in both water and an alkaline developer. Examples of such surfactants include those described in JP-A-2010-215608 and JP-A-2011-16746.

[0303] Among the surfactants described in the above publications, preferred surfactants that are insoluble or slightly soluble in water and alkaline developers include FC-4430 (manufactured by 3M), Surflon (registered trademark) S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Olfine (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and oxetane ring-opening polymers represented by the following formula (surf-1):

[0304] [ka]

[0305] Here, R, Rf, A, B, C, m, and n apply only to formula (surf-1), regardless of the above descriptions. R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. Examples of the divalent aliphatic group include an ethylene group, a 1,4-butylene group, a 1,2-propylene group, a 2,2-dimethyl-1,3-propylene group, and a 1,5-pentylene group, and examples of the trivalent or tetravalent aliphatic group include the following:

[0306] [ka] (In the formula, the dashed lines represent bonds and are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.)

[0307] Among these, a 1,4-butylene group, a 2,2-dimethyl-1,3-propylene group, and the like are preferred.

[0308] Rf is a trifluoromethyl group or a pentafluoroethyl group, preferably a trifluoromethyl group. m is an integer of 0 to 3, n is an integer of 1 to 4, and the sum of n and m is the valence of R, which is an integer of 2 to 4. A is 1. B is an integer of 2 to 25, preferably an integer of 4 to 20. C is an integer of 0 to 10, preferably 0 or 1. The order of the structural units in formula (surf-1) is not specified, and they may be bonded in blocks or randomly. The production of surfactants based on partially fluorinated oxetane ring-opening polymers is described in detail in the specification of U.S. Pat. No. 5,650,483, etc.

[0309] [(E) Solvent] The resist composition of the present invention may contain a solvent (organic solvent). The organic solvent is not particularly limited as long as it can dissolve the components described above and the components described below. Examples of such organic solvents include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone; 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, as described in paragraphs

[0144] and

[0145] of JP-A No. 2008-111103. Examples of suitable solvents include ethers such as ethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; lactones such as γ-butyrolactone; and mixed solvents thereof.

[0310] In the 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 (A) base polymer.

[0311] [Other ingredients] The resist composition of the present invention may further include a compound that decomposes in the presence of an acid to generate an acid (acid amplifier compound), an organic acid derivative, a fluorine-substituted alcohol, or a compound with a Mw of 3,000 or less whose solubility in a developer changes in response to the action of an acid (dissolution inhibitor). Examples of the acid amplifier compound include the compounds described in JP-A-2009-269953 and JP-A-2010-215608. Examples of the organic acid derivative, fluorine-substituted alcohol, and dissolution inhibitor include the compounds described in JP-A-2009-269953 and JP-A-2010-215608.

[0312] [Pattern formation method] When the resist composition of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied.

[0313] Therefore, the present invention provides a pattern forming method comprising the steps of forming a resist film on a substrate using the resist composition of the present invention, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer.

[0314] For example, the positive resist composition of the present invention is applied to a substrate for integrated circuit production (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective coating, etc.) or a substrate for mask circuit production (Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., so as to give a coating thickness of 0.01 to 2 μm. This is then pre-baked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0315] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, i-rays, EB (electron beam), EUV, X-rays, soft X-rays, excimer lasers (e.g., KrF, ArF), gamma rays, synchrotron radiation, and extreme ultraviolet radiation with a wavelength of 3 to 15 nm. When ultraviolet radiation, far ultraviolet radiation, i-rays, EUV, X-rays, soft X-rays, excimer lasers (e.g., KrF, ArF), gamma rays, synchrotron radiation, and extreme ultraviolet radiation with a wavelength of 3 to 15 nm are used as the high-energy radiation, a mask for forming a desired pattern is used, and the exposure dose is preferably 1 to 200 mJ / cm. 2 approximately, more preferably 10 to 100 mJ / cm 2 When EB (electron beam) 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 resist composition of the present invention is particularly suitable for fine patterning using high-energy rays such as KrF excimer laser, ArF excimer laser, EB, EUV, X-rays, soft X-rays, γ-rays, and synchrotron radiation, and is particularly suitable for fine patterning using EB or EUV.

[0316] After the exposure, PEB may be performed on a hot plate, 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.

[0317] After exposure or PEB, the substrate is developed using a developer such as an aqueous alkaline solution of 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 dipping, puddling, or spraying. The irradiated portions dissolve in the developer, while the unexposed portions do not, forming the desired positive pattern on the substrate.

[0318] Negative development can also be carried out to obtain a negative pattern by organic solvent development using a positive resist composition containing a base polymer containing an acid labile group.The developer used in this case 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.

[0319] After the development is completed, the resist film is rinsed. A solvent that is miscible with the developer but does not dissolve the resist film is preferred as the rinse solution. Preferred examples of such solvents include alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms.

[0320] 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, 1-octanol, and the like.

[0321] 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.

[0322] 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 hexyne, heptine, octyne, etc.

[0323] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0324] 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.

[0325] The developed hole or trench pattern can also be shrunk using thermal flow, RELACS, or DSA. A shrink agent is applied to the hole pattern, and the diffusion of an acid catalyst from the resist layer during baking causes crosslinking of the shrink agent on the surface of the resist, resulting in adhesion of the shrink agent to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds. Excess shrink agent is removed, and the hole pattern is shrunk. [Example]

[0326] The present invention will be specifically explained below by showing synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. The apparatuses used are as follows. ·1H-NMR: ECA-500 manufactured by JEOL Ltd.

[0327] [1] Synthesis of polymer compounds BF-1 to BF-8, RF-1 to RF-2 As a polymer compound (polymer additive) to be added to the resist composition, each monomer was combined and copolymerized in an isopropyl alcohol solvent, crystallized in hexane, and after repeated washing with hexane, isolated and dried to obtain a polymer compound having the composition shown below. The composition of the obtained polymer compound is 1 The H-NMR analysis values, molecular weight and dispersity are values ​​measured in terms of polystyrene by GPC using THF as a solvent.

[0328] [ka]

[0329] [2] Synthesis of base polymers P1-P38, RP1-RP5 To prepare the base polymer to be added to the resist composition, each monomer was combined and copolymerized in MEK under a nitrogen atmosphere, crystallized in hexane, and then repeatedly washed with hexane, isolated, and dried to obtain the base polymers with the compositions shown in Tables 1-1 to 1-3. 1 The H-NMR analysis values, molecular weight, and dispersity were measured using GPC with DMF as the solvent and converted into polystyrene equivalents. In Table 1, [-] indicates that the component or part number was not present.

[0330] [3] Synthesis of base polymer RP6 Each monomer was combined and copolymerized in THF under a nitrogen atmosphere, then isolated and dried. The composition of the resulting base polymer RP6 was: 1 The H-NMR analysis values, molecular weight, and dispersity were measured using GPC with THF as a solvent and converted into polystyrene equivalents. In Tables 1-1 to 1-3, [-] indicates that the component or number of parts was not present.

[0331] [Table 1-1]

[0332] [Table 1-2]

[0333] [Table 1-3]

[0334] The monomers used in the synthesis of the base polymer are as follows:

[0335] [ka]

[0336] [ka]

[0337] [ka]

[0338] [ka]

[0339] [ka]

[0340] [4] Preparation of chemically amplified resist composition Resist solutions were prepared by dissolving selected materials from the polymers (P-1 to P-38), comparative polymers (RP-1 to RP-7), polymers (BF-1 to BF-8), and comparative polymers (RF-1 to RF-2) listed above, as well as the photoacid generators (PAG-1 to PAG-6), acid diffusion inhibitors (Q-1 to Q-20), and comparative acid diffusion inhibitors (RQ-1 to RQ-2) listed below, in a solvent containing 0.01% by weight of the surfactant Polyfox 636 (Omnova). The resulting solution was then filtered through a 0.02 μm filter. The composition and performance of each resist solution are shown in Tables 2 to 6.

[0341] In Tables 2 to 6, the photoacid generators (PAG-1 to PAG-6) and acid diffusion inhibitors (Q-1 to Q-20, RQ-1 to RQ-2) are as follows.

[0342] [ka]

[0343] [ka]

[0344] [ka]

[0345] Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol) EL (Ethyl lactate) GBL (γ-butyrolactone)

[0346] [Sensitivity evaluation] The sensitivity was determined by the point where a 1:1 line and space pattern was formed, or where a 50 nm hole was formed on the wafer. op (mJ / cm 2 The smaller this value, the higher the sensitivity.

[0347] [LWR rating] E op The dimensions of the LS pattern obtained by irradiation at 10 points in the longitudinal direction of the line were measured, and the LWR was calculated as three times the standard deviation (σ) (3σ). The smaller this value, the less roughness and the more uniform the line width pattern obtained.

[0348] [CDU Rating] E op The dimensions of 50 holes were measured, and the standard deviation (σ) calculated from the results was tripled (3σ) to give the dimensional variation (CDU). The smaller this value, the smaller the variation in hole diameter, which is better.

[0349] [DOF evaluation] The depth of focus was evaluated by determining the focus range formed within a range of ±10% of the target CD dimension of the LS pattern. The larger this value, the wider the depth of focus.

[0350] [Resist peeling defect evaluation] The resist was spin-coated onto a Si substrate and pre-baked at 100°C for 60 seconds using a hot plate to produce a 50 nm thick resist film. The resist was then stripped using an organic solvent, PGME / PGMEA = 70% / 30%, and the resist residue on the wafer was observed for particles 60 nm or larger using SP7. If there were 300 particles or less, the result was rated as good (◎). If there were more than 300 particles, the result was rated as bad (×).

[0351] [EUV exposure evaluation] EUV Lithography Evaluation (1) [Examples 1-1 to 1-15, 2-1 to 2-43, Comparative Examples 1 to 7] Each chemically amplified resist composition (R1-1 to R1-15, R2-1 to R2-43, CR-1 to CR-7) listed in Tables 2 to 4 was spin-coated onto a Si substrate coated with a 20 nm thick silicon-containing spin-on hard mask SHB-A940 (43 wt % silicon) manufactured by Shin-Etsu Chemical Co., Ltd., and pre-baked at 100°C for 60 seconds using a hot plate to produce a 45 nm thick resist film. This was then exposed to light using an ASML EUV scanner NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination) to produce an LS pattern with 18 nm on-wafer dimensions and a 36 nm pitch, followed by PEB at 85°C for 60 seconds. The resist was then puddle-developed for 30 seconds using a 2.38 wt % TMAH aqueous solution, rinsed with a surfactant-containing rinse solution, and spin-dried to obtain a positive pattern. The obtained LS patterns were observed with a critical dimension SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, and the sensitivity, LWR, and depth of focus (DOF) were evaluated. These results are also shown in Tables 2 to 4, along with the results of resist peeling defects.

[0352] [Table 2]

[0353] [Table 3-1]

[0354] [Table 3-2]

[0355] [Table 4]

[0356] The results shown in Tables 2 to 4 confirm that the resist compositions of the present invention have a good balance between sensitivity and LWR and are excellent in reducing defects. On the other hand, Comparative Examples 1 and 2, which did not contain the (B) polymer compound and the (C) photoacid generator, were poor in sensitivity, LWR, DOF, and defects. Comparative Examples 3 to 6, which did not contain the (A) base polymer, had no repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring, and did not contain the (B) polymer compound and the (C) photoacid generator, were poor in sensitivity, LWR, DOF, and defects. Comparative Example 7, which did not contain the (B) polymer compound and the (C) photoacid generator, was poor in sensitivity, LWR, DOF, and defects.

[0357] EUV Lithography Evaluation (2) [Examples 3-1 to 3-13, Comparative Examples 7 to 8] Each chemically amplified resist composition (R3-1 to R3-13, CR-1, and CR-6) listed in Table 5 was spin-coated onto a Si substrate coated with a 20-nm-thick silicon-containing spin-on hard mask (SHB-A940, manufactured by Shin-Etsu Chemical Co., Ltd.) containing 43% silicon by weight. The resulting resist was then prebaked at 105°C for 60 seconds using a hot plate to produce a 60-nm-thick resist film. This resist was then exposed to light using an ASML EUV scanner NXE3300 (NA 0.33, σ 0.9, Conversional illumination) to produce a 23-nm LS pattern with a 46-nm pitch. The resist was then subjected to PEB at 85°C for 60 seconds. The resist was then puddled with a 2.38% by weight TMAH aqueous solution for 30 seconds, rinsed with a surfactant-containing rinse solution, and spin-dried to obtain a positive-tone pattern. The obtained LS patterns were observed with a critical dimension SEM (CG6300) manufactured by Hitachi High-Tech Corporation, and the sensitivity, LWR, and depth of focus (DOF) were evaluated. These results are also shown in Table 5, along with the results of resist peeling defects.

[0358] [Table 5]

[0359] The results shown in Table 5 confirm that the resist composition of the present invention has a good balance between sensitivity and LWR and is excellent in reducing defects. On the other hand, Comparative Example 7, which did not contain the (B) polymer compound and the (C) photoacid generator, was poor in LWR, DOF, and defects. Comparative Example 8, which did not contain the (A) base polymer having a repeating unit with an acid labile group containing a fluorine atom-containing aromatic ring and did not contain the (B) polymer compound and the (C) photoacid generator, was poor in sensitivity, LWR, DOF, and defects.

[0360] [ArF immersion exposure evaluation] [Examples 4-1 to 4-7, Comparative Examples 9 to 10] Each chemically amplified resist composition (R4-1 to R4-7, CR-1, CR-6) listed in Table 6 was spin-coated onto a silicon substrate coated with a 20 nm thick silicon-containing spin-on hard mask (SHB-A940, manufactured by Shin-Etsu Chemical Co., Ltd.) (43% silicon by weight) and pre-baked at 105°C for 60 seconds using a hot plate to produce a 60 nm thick resist film. This was then exposed to light using an ArF excimer laser scanner (Nikon Corporation NSR-S610C, NA 1.30, σ 0.98 / 0.78, 35-degree cross-pole illumination, azimuthally polarized illumination, 6% halftone phase-shift mask) to form a 50 nm hole pattern on the wafer with a 100 nm pitch, followed by PEB at 85°C for 60 seconds. This was followed by paddle development with n-butyl acetate for 30 seconds and spin drying to obtain a negative pattern. The obtained hole pattern was observed with a critical dimension SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, and the sensitivity, CDU, and depth of focus (DOF) were evaluated. These results are also shown in Table 6, along with the results of resist peeling defects.

[0361] [Table 6]

[0362] The results shown in Table 6 confirm that the resist composition of the present invention has a good balance between sensitivity and CDU and is excellent in terms of defect prevention. On the other hand, Comparative Example 9, which did not contain the (B) polymer compound and the (C) photoacid generator, was poor in terms of CDU and defect prevention. Furthermore, Comparative Example 10, which did not contain the (A) base polymer having a repeating unit with an acid labile group containing a fluorine atom-containing aromatic ring and did not contain the (B) polymer compound and the (C) photoacid generator, was poor in terms of CDU, DOF, and defect prevention.

[0363] This specification includes the following inventions.

[0364] [1]: (A) a base polymer containing at least one repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring and at least one repeating unit having a phenolic hydroxy group, and (B) a polymer compound having a repeating unit represented by the following general formula (1): [ka] (In the formula, R B are independently a hydrogen atom or a methyl group. Ra is a methyl group or a trifluoromethyl group. R B1 , R B2 are independently hydrogen atoms (except R B1 and R B2 and R are hydrogen atoms, or a linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms, and R B1 and R B2 may be bonded to form a ring, in which case R B1 and R B2 R represents a divalent organic group having a total of 2 to 4 carbon atoms. B3 is a linear, branched, or cyclic alkyl group, in which some or all of the hydrogen atoms may be substituted with fluorine atoms, and which may contain an iminosulfonyl group. 1 , X 2 , X 3 , X 4 are independently -C(=O)-, -C(=O)-O-, -C(=O)-OR B7 -, -O-, -C(=O)-RB7 -C(=O)- and -C(=O)-OR B7 -C(=O)-O-. R B7 R is a linear, branched, or cyclic alkylene group having 1 to 10 carbon atoms. B4 is an alkylene group or alkanetriyl group having a cyclic structure and having 4 to 12 carbon atoms, which may be substituted with fluorine; R B5 is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, which may be substituted with fluorine; R B4 and R B5 may be bonded to form a ring having 3 to 12 carbon atoms. B6 is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, which may be substituted with fluorine. n1 is 1 or 2. a-1, b-1, b-2, and b-3 satisfy the ranges 0<(a-1)<1, 0<(b-1)<1, 0≦(b-2)<1, 0≦(b-3)<1, and 0<(a-1)+(b-1)+(b-2)+(b-3)≦1. A resist composition comprising (C) a photoacid generator, (D) an acid diffusion controller, and (E) a solvent, wherein the component (D) is contained in an amount of 11 to 50 parts by mass per 100 parts by mass of the component (A).

[0365] [2]: The resist composition according to [1] above, wherein the component (A) comprises a polymer whose solubility in a developer is changed by the action of an acid, the polymer comprising a repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring, represented by the following formula (A1), a repeating unit having a phenolic hydroxy group, and a repeating unit that generates an acid upon exposure, represented by any of the following formulae (C1) to (C4): [ka] (In the formula, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. A is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OZ A1-, and the phenylene group and naphthylene group may be substituted with a halogen atom, a methoxy group, or a trifluoromethoxy group. A1 is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond, or a lactone ring, or a phenylene group or naphthylene group. * represents a bond to a carbon atom in the main chain. R C and R D are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, and R C and R D and may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 1 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms. 2 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. n1 is an integer of 1 or 2. n2 is an integer of 0 to 5. n3 is an integer of 0 to 2. [ka] (In the formula, R A is the same as above. Z 1 is a single bond or a phenylene group. 2 is *-C(=O)-OZ 21 -, *-C(=O)-NH-Z 21 -or*-OZ 21 -It is. Z 21 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 3 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OZ 31 -It is. Z 31 Z is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group. 4 is a single bond or *-Z41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-C(=O)-OZ 51 -, *-C(=O)-N(H)-Z 51 -or*-OZ 51 -It is. Z 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. * represents a carbon atom in the main chain, Z 1 , or Z 3 Represents a bond with R. 21 and R 22 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond or a carbamate bond. 1 and Rf 2 Rf are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4 Rf are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms, provided that all Rf 5 and Rf 6 and cannot simultaneously become hydrogen atoms. - is a non-nucleophilic counterion. + is an onium cation, and c is an integer of 0 to 3.

[0366] [3]: The resist composition according to the above [1] or [2], further comprising a surfactant in addition to the component (B).

[0367] [4]: A pattern forming method comprising the steps of: forming a resist film on a substrate using the resist composition according to any one of [1] to [3] above; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

[0368] [5]: The pattern forming method according to the above [4], wherein the high-energy beam is i-line, KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light having a wavelength of 3 to 15 nm.

[0369] [6]: The pattern forming method according to the above [4] or [5], characterized in that an exposed area is dissolved by using an alkaline aqueous solution as the developer, and a positive pattern in which an unexposed area is not dissolved is obtained.

[0370] [7]: The pattern forming method according to the above [4] or [5], characterized in that an organic solvent is used as the developer to dissolve the unexposed areas, thereby obtaining a negative pattern in which the exposed areas do not dissolve.

[0371] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. (A) a base polymer containing at least one repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring and at least one repeating unit having a phenolic hydroxy group; (B) a polymer compound having a repeating unit represented by the following general formula (1): 【Chemistry 1】 (In the formula, R Ｂ are independently a hydrogen atom or a methyl group. Ra is a methyl group or a trifluoromethyl group. R Ｂ１ , R Ｂ２ are independently hydrogen atoms (provided that R Ｂ１ and R Ｂ２ and R are hydrogen atoms, or a linear, branched, or cyclic alkyl group having 1 to 4 carbon atoms; Ｂ１ and R Ｂ２ may be bonded to form a ring, in which case R Ｂ１ and R Ｂ２ represents a divalent organic group having a total of 2 to 4 carbon atoms. Ｂ３ is a linear, branched, or cyclic alkyl group, in which some or all of the hydrogen atoms may be substituted with fluorine atoms, and which may contain an iminosulfonyl group. １ , X ２ , X ３ , X ４ are independently —C(═O)—, —C(═O)—O—, or —C(═O)—O—R Ｂ７ -, -O-, -C(=O)-R Ｂ７ -C(=O)-, and -C(=O)-O-R Ｂ７ -C(=O)-O-. Ｂ７ is a linear, branched, or cyclic alkylene group having 1 to 10 carbon atoms. Ｂ４ is an alkylene group or alkanetriyl group having a cyclic structure and having 4 to 12 carbon atoms, which may be substituted with fluorine; R Ｂ５ is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, which may be substituted with fluorine; R Ｂ４ and R Ｂ５ may be bonded to form a ring having 3 to 12 carbon atoms. Ｂ６ is a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, which may be substituted with fluorine. n1 is 1 or 2. a-1, b-1, b-2, and b-3 satisfy the ranges 0<(a-1)<1, 0<(b-1)<1, 0≦(b-2)<1, 0≦(b-3)<1, and 0<(a-1)+(b-1)+(b-2)+(b-3)≦1. (C) a photoacid generator, (D) an acid diffusion controller represented by any one of the following formulas (1-I) to (4-I): 【Chemistry 2】 (In formula (1-I), n1 is an integer of 0 to 4. m is an integer of 1 to 4. L is a single bond, an ether bond, or an ester bond. When n is 2 or more, each L may be the same or different. R 1A is a hydroxy group, or a linear, branched, or cyclic alkyl group or alkoxy group having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be substituted with halogen atoms, a linear, branched, or cyclic acyloxy group having 2 to 6 carbon atoms, or a linear, branched, or cyclic alkylsulfonyloxy group having 1 to 4 carbon atoms, or a fluorine atom, chlorine atom, bromine atom, amino group, nitro group, cyano group, —NR 1B —C(═O)—R 1C , or —NR 1B —C(═O)—O—R 1C , where R 1B is a hydrogen atom or a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, and R 1C is a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, or a linear, branched, or cyclic alkenyl group having 2 to 8 carbon atoms. R 2A is a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 10 carbon atoms, in which a hydrogen atom in the hydrocarbyl group is substituted with a halogen atom, and / or a —CH 2 — in the hydrocarbyl group is substituted with an ether bond or a carbonyl group. In formula (2-I), n2 is an integer of 1 to 5. m is an integer of 0 to 4. R 1F is an alkyl group or fluorinated alkyl group having 6 to 18 carbon atoms, and —CH 2 — in the alkyl group may be substituted with an ether bond or a carbonyl group. However, R 1F has at least one linear structure having 6 or more carbon atoms. When n2 is 2 or more, each R 1F may be the same or different. Furthermore, the alkyl group may contain, as a partial structure, a ring structure selected from a cyclopentane ring, a cyclohexane ring, an adamantane ring, and a norbornyl ring at the terminal or between the carbon-carbon bonds. L is the same as above. R 2A is a halogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 10 carbon atoms, and a hydrogen atom in the hydrocarbyl group may be substituted with a halogen atom, or a —CH 2 — in the hydrocarbyl group may be substituted with an ether bond or a carbonyl group. In formula (3-I), R 1 and R 2 are each independently a hydrogen atom, a hydroxy group, or a hydrocarbyl group having 1 to 12 carbon atoms, and a hydrogen atom in the hydrocarbyl group may be substituted with a heteroatom-containing group, and a —CH 2 — in the hydrocarbyl group may be substituted with —O— or —C(═O)—. R 1 and R 2 may also be bonded to each other to form a ring together with the carbon atoms to which they are attached. R f1 and R f2 each independently represent a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that at least one of them is a fluorine atom or a trifluoromethyl group. L 1 is a single bond or a hydrocarbylene group having 1 to 15 carbon atoms, in which a hydrogen atom in the hydrocarbylene group may be substituted with a heteroatom-containing group, and in which —CH 2 — in the hydrocarbylene group may be substituted with —O— or —C(═O)—. L 2 is a single bond, an ether bond or an ester bond. Ar is an aromatic group having 3 to 15 carbon atoms and a valence of (n3+1), and some or all of the hydrogen atoms of the aromatic group may be substituted with a substituent. n3 is an integer that satisfies 1≦n3≦5. In formula (4-I), R 1' and R 2' each independently represent a halogen atom other than iodine, a hydroxy group, an amino group, a nitro group, a cyano group, or a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 15 carbon atoms which may contain a halogen atom, a hydroxy group, a nitro group, a cyano group, or a heteroatom, and a methylene group in the hydrocarbon group may be replaced by an ether bond (-O-) or a carbonyl group (-CO-). L a and L b are each a single bond, an ether bond, an ester bond, a sulfonate ester bond or a carbonate bond. L 1' represents a linear, branched, or cyclic divalent hydrocarbon group having 4 to 12 carbon atoms, in which a hydrogen atom may be substituted with a halogen atom, a hydroxy group, a nitro group, or a cyano group, and a methylene group in the hydrocarbon group may be substituted with an ether bond (—O—) or a carbonyl group (—CO—). L 2′ is a single bond, an ether bond, an ester bond or a carbonate bond. L 3′ is a single bond or a hydrocarbylene group having 1 to 15 carbon atoms which may contain a heteroatom. n4 and n5 are 0 or 1. n6 represents an integer from 0 to 4 when n4=0, and represents an integer from 0 to 6 when n4=1. n7 represents an integer of 0 to 3 when n5=0, and represents an integer of 0 to 5 when n5=1. x represents an integer of 1 to 5 when n4=0, and represents an integer of 1 to 7 when n4=1. y represents an integer of 1 to 4 when n5=0, and an integer of 1 to 6 when n5=1. n6, n7, x, and y are integers that satisfy 1≦n6+x≦5 when n4=0, 1≦n6+x≦7 when n4=1, 1≦n7+y≦4 when n5=0, and 1≦n7+y≦6 when n5=1. When n6≧2, multiple R 1 s may be the same or different, and when n7≧2, multiple R 2 s may be the same or different. wherein A + is an onium cation; and (E) Solvent and the component (D) is contained in an amount of 11 to 50 parts by mass per 100 parts by mass of the component (A).

2. 2. The resist composition according to claim 1, wherein the component (A) comprises a polymer whose solubility in a developer is changed by the action of an acid, the polymer comprising a repeating unit having an acid labile group containing a fluorine atom-containing aromatic ring, represented by the following formula (A1): a repeating unit having a phenolic hydroxy group, and a repeating unit that generates an acid upon exposure, represented by any of the following formulas (C1) to (C4): 【Transformation 3】 (In the formula, R Ａ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z Ａ represents a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-Z Ａ１ -, and the phenylene group and naphthylene group may be substituted with a halogen atom, a methoxy group, or a trifluoromethoxy group. Ａ１ is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or naphthylene group. * represents a bond to a carbon atom in the main chain. R Ｃ and R Ｄ are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, and R Ｃ and R Ｄ may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R １ are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms. R ２ are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. n1 is an integer of 1 or 2. n2 is an integer of 0 to 5. n3 is an integer of 0 to 2. 【Chemistry 4】 (In the formula, R Ａ is the same as above. Z １ is a single bond or a phenylene group. Z ２ is *-C(=O)-O-Z ２１ -, *-C(=O)-NH-Z ２１ - or *-O-Z ２１ - is. Z ２１ represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z ３ represents a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-Z ３１ - is. Z ３１ is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or naphthylene group. Z ４ is a single bond or *-Z ４１ -C(=O)-O-. Z ４１ is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. Z ５ represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-C(=O)-O-Z ５１ -, *-C(=O)-N(H)-Z ５１ - or *-O-Z ５１ - is. Z ５１ represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. * denotes a carbon atom in the main chain, Z １ , or Z ３ Represents a bond with . R ２１ and R ２２ are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. ２１ and R ２２ and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. L １ is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond or a carbamate bond. Rf １ and Rf ２ are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. Rf ３ and Rf ４ are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. Rf ５ and Rf ６ are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. ５ and Rf ６ cannot simultaneously become a hydrogen atom. M － is a non-nucleophilic counterion. A ＋ is an onium cation. c is an integer from 0 to 3.

3. 2. The resist composition according to claim 1, further comprising a surfactant in addition to the component (B).

4. 4. A pattern forming method, comprising: forming a resist film on a substrate using the resist composition according to claim 1; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

5. 5. The pattern forming method according to claim 4, wherein the high-energy beam is i-line, KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light having a wavelength of 3 to 15 nm.

6. 5. The pattern forming method according to claim 4, wherein an alkaline aqueous solution is used as the developer to dissolve the exposed areas and to obtain a positive pattern in which the unexposed areas do not dissolve.

7. 5. The pattern forming method according to claim 4, wherein an organic solvent is used as the developer to dissolve the unexposed areas, thereby obtaining a negative pattern in which the exposed areas do not dissolve.

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