Polymer, resist composition and pattern forming method

Abstract

To provide a polymer, a resist composition, and a pattern forming method which can form a pattern with high sensitivity, high resolution, and high contrast and with small variation in pattern width (LWR) and small in-plane uniformity of the pattern (CDU) with high energy rays.SOLUTION: The present invention relates to a polymer to generate an acid by light exposure and to change in solubility to a developing liquid by the action of the acid, the polymer comprising a repeating unit represented by formula (A-2).SELECTED DRAWING: None

Description

[Technical field]

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

[0002] In recent years, the increasing integration of integrated circuits has led to a demand for finer pattern formation, and chemically amplified resists using acid as a catalyst are used exclusively for processing patterns of 0.2 μm or less. In addition, high-energy rays such as ultraviolet rays, far ultraviolet rays, and electron beams (EB) are used as exposure sources for this purpose, and electron beam lithography, which is used as an ultrafine processing technology, is also indispensable as a processing method for photomask blanks when producing photomasks for semiconductor manufacturing.

[0003] Polymers with a large amount of aromatic skeletons having acidic side chains, such as polyhydroxystyrene, have been usefully used as resist materials for KrF excimer lasers, but have not been used as materials for ArF excimer laser resists because they exhibit high absorption for light with wavelengths of around 200 nm. However, they are important materials for resist compositions for EB lithography, which is a powerful technique for forming patterns smaller than the processing limit of ArF excimer lasers, and for resist compositions for extreme ultraviolet (EUV) lithography, because they provide high etching resistance.

[0004] As the base polymer of a positive EB lithography resist composition or an EUV lithography resist composition, a material is mainly used that uses an acid generated from a photoacid generator by irradiation with high energy rays as a catalyst to deprotect an acid-decomposable protecting group masking an acidic functional group of a phenol side chain of the base polymer, thereby making the base polymer soluble in an alkaline developer. In addition, as the acid-decomposable protecting group, a tertiary alkyl group, a tert-butoxycarbonyl group, an acetal group, etc. have mainly been used. Here, the use of a protecting group such as an acetal group, which requires a relatively small activation energy for deprotection, has the advantage of being able to obtain a highly sensitive resist film, but if the diffusion of the generated acid is not sufficiently suppressed, a deprotection reaction will occur even in the unexposed parts of the resist film, leading to problems such as deterioration of line edge roughness (LER) and deterioration of the in-plane uniformity (CDU) of the pattern.

[0005] Various improvements have been made to the control of resist sensitivity and pattern profile by the selection and combination of materials used in the resist composition, process conditions, etc. One of these improvements is the problem of acid diffusion, which has a significant effect on the resolution of chemically amplified resist compositions. This problem of acid diffusion has been the subject of much investigation because it has a significant effect on sensitivity and resolution.

[0006] In addition, in order to improve sensitivity, attempts have been made to introduce multiple bonds or aromatic rings into the acid labile groups of the base polymer of the resist composition. Although the introduction of these substituents has improved performance to a certain extent, satisfactory results have not yet been obtained. Since the allyl cations and benzyl cations generated after the acid elimination reaction are more stable than normal carbocations, base polymers designed to generate primary or secondary benzyl cations after the acid elimination reaction have also been considered, but the reactivity to acids is insufficient, so satisfactory performance improvement has not been achieved. Conversely, the tertiary allyl cations and tertiary benzyl cations generated after the acid elimination reaction are highly reactive to acids, and it has been confirmed that a thermal elimination reaction proceeds in part during polymerization of the base polymer, and issues remain in the polymer production process (Patent Document 1). 1~12 ). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2013-53196 A [Patent Document 2] JP 2018-92159 A [Patent Document 3] JP 2008-268741 A [Patent Document 4] JP 2019-120759 A [Patent Document 5] JP 2020-085917 A [Patent Document 6] Patent No. 6782569 [Patent Document 7] JP 2019-214554 A [Patent Document 8] JP 2002-156761 A [Patent Document 9] JP 2006-030232 A [Patent Document 10] JP 2019-008287 A [Patent Document 11] JP 2019-038998 A [Patent Document 12] JP 2019-074733 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a polymer, a resist composition, and a pattern formation method using the same, which enable pattern formation with high sensitivity, high resolution, and high contrast, particularly when using high-energy rays, and with small line width variation (LWR) and pattern within wafer uniformity (CDU). [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides A polymer which generates an acid upon exposure to light and changes its solubility in a developer by the action of the acid, A polymer containing a repeating unit represented by the following formula (A-1) and one or more repeating units represented by the following formulas (B-1) to (B-4): to provide. [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, (main chain)-C(=O)-OZ A1 -, or an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a phenylene group or naphthylene group which may contain a halogen atom; Z A1 R is an alkoxy group having 1 to 10 carbon atoms which may contain a heteroatom or a fluorine atom, a hydroxyl group, a linear, branched or cyclic alkanediyl group having 1 to 20 carbon atoms which may contain an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. B and R C each independently represents a linear, branched or cyclic hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom; R B and R C may be bonded to each other to form a ring structure. 1a R each independently represents a halogen atom, a cyano group, an acyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine-containing alkyl group having 1 to 5 carbon atoms, or a fluorine-containing alkoxy group having 1 to 5 carbon atoms. 1b each independently represents a linear, branched or cyclic 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 2, n3 is an integer of 0 to 5, and n4 is an integer of 0 to 2. Z 1 is a single bond or a phenylene group. Z 2is a single bond, -C(=O)-OZ 21 -, -C(=O)-NH-Z 21 -or-OZ 21 -It is. 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 (main chain)-C(=O)-OZ 31 -It is. 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, a methylene group, or -Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom, an ether bond, or an ester bond. Z 5 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -C(=O)-OZ 51 -, -C(=O)-NH-Z 51 -or-OZ 51 -It is. 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. R 21 and R 22 R is each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. L 11is 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. M - is a non-nucleophilic counterion. A + is an onium cation. c is an integer from 0 to 3.

[0010] In such a polymer, the repeating unit A having an acid labile group including a phenolic hydroxyl group contributes to the change in solubility in a developer, and the acid labile units and the sensitizing units that generate secondary electrons in the base polymer can be increased at the same time. In addition, the repeating unit B that generates acid upon exposure can suppress excessive acid diffusion and the diffusion of secondary electrons generated in the sensitizing sites. Therefore, with such a polymer, it is possible to provide a resist material that can simultaneously achieve high sensitivity, high resolution, and high contrast under high energy rays, and enables the formation of a pattern with small LWR and CDU, as well as a pattern formation method using the same.

[0011] The repeating unit represented by the formula (A-1) is preferably a repeating unit represented by the following formula (A-2). [ka] (In the formula, R A , Z A , R B , R C , R 1a , R 1b , n1, n2, and n3 are the same as above.)

[0012] Such a polymer can have good solvent solubility.

[0013] In addition, R in the formula (A-1) 1a is preferably any one of a fluorine atom, a trifluoromethyl group, and a trifluoromethoxy group. (

[0014] Such a polymer can be favorably used for high-energy beam lithography.

[0015] In addition, A in the formulas (B-2) to (B-4) + is preferably a cation represented by the following formula (cation-1) or (cation-2). [ka] (In the formula, R 11 , R 12 and R 13 each independently represents a linear, branched or cyclic monovalent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. 11 , R 12 and R 13 Any two of R may be bonded to each other to form a ring together with the sulfur atom in the formula. 14 and R 15 are each independently a linear, branched or cyclic monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom.

[0016] Such a polymer can be favorably used for high-energy beam lithography.

[0017] The polymer preferably further contains a repeating unit represented by the following formula (a-1) or (a-2). [ka] (In the formula, R A , Z A is the same as above. ZB R is a single bond, (main chain) -C(=O)-O-, or an alkanediyl group having 1 to 10 carbon atoms which may contain an ester group, an ether group, or a carbonyl group. b is a linear, branched or cyclic hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a halogen atom, an alkoxy group which may contain fluorine, or a cyano group. p is an integer of 0 to 4. X A and X B each independently represents an acid labile group not containing a fluorine-containing aromatic ring.

[0018] Such a polymer can be favorably used for high-energy beam lithography.

[0019] Moreover, the polymer preferably further contains a repeating unit represented by the following formula (C-1). [ka] (In the formula, R A is the same as above. Z B R is a single bond or (main chain) -C(=O)-O-, or an alkanediyl group having 1 to 10 carbon atoms which may contain an ester group, an ether group, or a carbonyl group. b1 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. m is an integer of 1 to 4, k is an integer of 0 to 3, and m+k is an integer of 4 or less.

[0020] Such a polymer can be favorably used for high-energy beam lithography.

[0021] In addition, the polymer preferably further contains a repeating unit represented by the following formula (D-1). [ka] (In the formula, R A , Z A , is the same as above. Y A is a hydrogen atom, or a polar group containing at least one structure selected from a hydroxy group, a cyano group, a carbonyl group, a carboxy group, an ether bond, an ester bond, a sulfonate ester bond, a sulfonamide bond, a carbonate bond, a lactone ring, a sultone ring, a sulfur atom, and a carboxylic acid anhydride.

[0022] Such a polymer can be favorably used for high-energy beam lithography.

[0023] The present invention also provides a resist composition comprising the above polymer.

[0024] Such a resist composition can provide a resist material that enables the formation of a pattern with high sensitivity, high resolution, high contrast, and small LWR and CDU when exposed to high energy rays.

[0025] It is preferable that the resist composition further contains an organic solvent.

[0026] With such a resist composition, a resist composition that is suitable for high-energy beam lithography can be obtained.

[0027] The resist composition preferably further contains a photoacid generator other than the photoacid generator bonded to the polymer chain.

[0028] With such a resist composition, a resist composition that is suitable for high-energy beam lithography can be obtained.

[0029] In addition, the resist composition preferably further contains a quencher.

[0030] With such a resist composition, a resist composition that is suitable for high-energy beam lithography can be obtained.

[0031] Moreover, the resist composition preferably further contains a surfactant that is insoluble or poorly soluble in water but soluble in an alkaline developer, and / or a surfactant that is insoluble or poorly soluble in water and an alkaline developer.

[0032] With such a resist composition, a resist composition that is suitable for high-energy beam lithography can be obtained.

[0033] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: (i) forming a resist film on a substrate using the resist composition; (ii) exposing the resist film to high energy radiation; (iii) developing the exposed resist film with a developer; The present invention provides a pattern forming method comprising the steps of:

[0034] Such a pattern formation method can provide a pattern formation method that has high sensitivity, high resolution, high contrast, and small LWR and CDU when using high-energy radiation.

[0035] The high energy radiation in the step (ii) is preferably i-rays, KrF excimer laser light, ArF excimer laser light, electron beams, or extreme ultraviolet rays having a wavelength of 3 to 15 nm.

[0036] In the pattern formation method of the present invention, such high energy rays can be used.

[0037] In addition, the developer in the step (iii) is an aqueous alkaline solution, which dissolves the exposed areas and leaves the unexposed areas insoluble, thereby obtaining a positive pattern.

[0038] In addition, the developer in the step (iii) may be an organic solvent, which dissolves the unexposed areas and leaves a negative pattern in which the exposed areas are insoluble.

[0039] The resist composition of the present invention can form either a positive or negative pattern by selecting the developer. Effect of the Invention

[0040] As described above, by using the polymer of the present invention, a resist composition containing the polymer, and a pattern formation method, it is possible to obtain a resist pattern that has high sensitivity, small LWR and CDU, high contrast, excellent resolution, and a wide process margin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] As described above, there has been a demand for the development of a resist composition that achieves even higher sensitivity and resolution and improves line LWR and hole CDU in acid-catalyzed chemically amplified resist compositions.

[0042] Means for Solving the Problems The present inventors have conducted extensive research in order to achieve the above-mentioned object, and as a result have found that by using a resist material containing a polymer including a repeating unit having a phenolic hydroxyl group as an acid labile group, and a repeating unit that generates acid upon exposure, it is possible to form a pattern with high sensitivity, high contrast, excellent resolution, and a wide process margin that is also excellent in LWR of a line pattern and CDU of a hole pattern, and have completed the present invention.

[0043] That is, the present invention provides: A polymer which generates an acid upon exposure to light and changes its solubility in a developer by the action of the acid, The polymer includes a repeating unit represented by the following formula (A-1) and one or more repeating units represented by the following formulas (B-1) to (B-4). [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, (main chain)-C(=O)-OZ A1 -, or an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a phenylene group or naphthylene group which may contain a halogen atom; Z A1 R is an alkoxy group having 1 to 10 carbon atoms which may contain a heteroatom or a fluorine atom, a hydroxyl group, a linear, branched or cyclic alkanediyl group having 1 to 20 carbon atoms which may contain an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. B and R C each independently represents a linear, branched or cyclic hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom; R B and R C may be bonded to each other to form a ring structure. 1a R each independently represents a halogen atom, a cyano group, an acyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine-containing alkyl group having 1 to 5 carbon atoms, or a fluorine-containing alkoxy group having 1 to 5 carbon atoms. 1b each independently represents a linear, branched or cyclic 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 2, n3 is an integer of 0 to 5, and n4 is an integer of 0 to 2. Z 1 is a single bond or a phenylene group. Z 2 is a single bond, -C(=O)-OZ 21 -, -C(=O)-NH-Z 21 -or-OZ 21 -It is. 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 (main chain)-C(=O)-OZ 31-It is. 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, a methylene group, or -Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom, an ether bond, or an ester bond. Z 5 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -C(=O)-OZ 51 -, -C(=O)-NH-Z 51 -or-OZ 51 -It is. 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. R 21 and R 22 R is each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. L 11 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. M - is a non-nucleophilic counterion. A + is an onium cation. c is an integer from 0 to 3.

[0044] The present invention will be described in detail below, but the present invention is not limited thereto.

[0045] [Polymer (base polymer)] The polymer of the present invention contains a repeating unit having an acid labile group containing a phenolic hydroxyl group, and a repeating unit that generates an acid upon exposure to light.

[0046] [Repeating unit A having an acid labile group containing a phenolic hydroxyl group] The polymer (base polymer) of the present invention contains a repeating unit having an acid labile group containing a phenolic hydroxyl group (hereinafter, also referred to as repeating unit A). Repeating unit A is represented by the following formula (A-1). [ka]

[0047] In formula (A-1), R A each independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z A is a single bond, (main chain)-C(=O)-OZ A1 Z is an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a phenylene group or naphthylene group which may contain a halogen atom. A1 is an alkoxy group having 1 to 10 carbon atoms which may contain a heteroatom or a fluorine atom, a hydroxyl group, a linear, branched or cyclic alkanediyl group (aliphatic hydrocarbylene group) having 1 to 20 carbon atoms which may contain an ether bond, an ester bond or a lactone ring, a phenylene group, or a naphthylene group.

[0048] The alkanediyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specifically, the alkanediyl group may be a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, a propane-2,2-diyl group, a butane-1,1-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-2,3-diyl group, a butane-1,4-diyl group, a 1,1-dimethylethane-1,2-diyl group, a pentane-1,5-diyl group, a 2-methylbutane-1,2-diyl group, a hexamethylbutane-1,5 ... Examples of the divalent groups include alkanediyl groups such as acetonitrile-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, and decane-1,10-diyl group; cycloalkanediyl groups such as cyclopropanediyl group, cyclobutane-1,1-diyl group, cyclobutanediyl group, cyclopentanediyl group, and cyclohexanediyl group; divalent polycyclic saturated hydrocarbon groups such as adamantanediyl group and norbornanediyl group; and divalent groups obtained by combining these groups.

[0049] Z in formula (A-1) A Examples of structures in which R is changed include, but are not limited to, those shown below. A is the same as above, and the dashed line represents R B and R C represents a bond to the carbon atom to which it is attached. [ka]

[0050] [ka]

[0051] In formula (A-1), R B and R Care each independently a linear, branched or cyclic hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, and specific examples of such alkyl groups include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an s-butyl group, a t-butyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, an n-octyl group, a norbornyl group, a tricyclodecanyl group and an adamantyl group.

[0052] In formula (A-1), R B and R C may be bonded to each other to form a ring structure. Specific examples include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. Among these, a cyclopentane ring and a cyclohexane ring are preferred.

[0053] In formula (A-1), n1 represents an integer of 1 or 2. Of these, it is preferable that n1=1.

[0054] In formula (A-1), R 1a are each independently any one of a halogen atom, a cyano group, an acyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine-containing alkyl group having 1 to 5 carbon atoms, and a fluorine-containing alkoxy group having 1 to 5 carbon atoms. Among these, a fluorine atom or a fluorine-containing alkoxy group having 1 to 5 carbon atoms is preferred, and a fluorine atom, a trifluoromethyl group, or a trifluoromethoxy group is more preferred.

[0055] In formula (A-1), n2 represents an integer of 0 to 2.

[0056] In formula (A-1), R 1b are each independently a linear, branched or cyclic hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, and specifically, R B and R C The same can be mentioned.

[0057] n3 represents an integer of 0 to 5, and is preferably 0 or 1.

[0058] n4 represents an integer of 0 to 2. When n4=0, it represents a benzene ring, when n4=1 it represents a naphthalene ring, and when n4=2 it represents an anthracene ring, but from the viewpoint of solvent solubility, n4=0 is preferably a benzene ring.

[0059] The repeating unit A represented by formula (A-1) is more preferably represented by the following formula (A-2). [ka] (In the formula, R A , Z A , R B , R C , R 1a , R 1b , n1, n2, and n3 are the same as above.)

[0060] [Synthesis of Monomer A represented by Formula (A-1)] The repeating units A represented by the above formulae (A-1) and (A-2) can be produced, for example, from a monomer A-1 obtained according to the following scheme: As an example, synthesis of a monomer represented by the following formula (monomer A-1) will be described below, but the synthesis method is not limited thereto. [ka] (In the formula, R A , Z A , R B , R C , R 1a , R 1b , n1, n2, n3, and n4 are the same as above. hal is a halogen atom other than a fluorine atom.)

[0061] The first step is a step in which a ketone compound (raw material 1), which is commercially available or can be synthesized by a known synthesis method, is reacted with a Grignard reagent or an organolithium reagent to obtain a tertiary benzyl alcohol (intermediate 1).

[0062] The reaction can be carried out by a known organic synthesis method. Specifically, a ketone compound (raw material 1) diluted with the solvent used is dropped into a commercially available Grignard reagent or an organolithium reagent prepared by a known method or a known product. The reaction temperature is from room temperature to the boiling point of the solvent used. The reaction time is usually about 30 minutes to 2 hours, although it is desirable to follow the reaction by gas chromatography (GC) or silica gel thin layer chromatography (TLC) in terms of yield and complete the reaction. Tertiary benzyl alcohol (intermediate 1) can be obtained from the reaction mixture by a conventional aqueous work-up. The obtained tertiary benzyl alcohol (intermediate 1) can be purified according to conventional methods such as distillation, chromatography, and recrystallization, if necessary.

[0063] The second step is a step of obtaining intermediate 2 by introducing a polymerizable group via an ester bond into the tertiary benzyl alcohol (intermediate 1) obtained in the first step.

[0064] The reaction can be carried out by a known organic synthesis method. Specifically, the tertiary alcohol of intermediate 1 is dissolved in a solvent such as toluene, hexane, THF, or acetonitrile in the presence of an organic base such as triethylamine or pyridine, and an acid halide such as methacrylic acid chloride or acrylic acid chloride is added dropwise to carry out the reaction. 4-Dimethylaminopyridine may be added to accelerate the reaction rate. The reaction temperature is from 5°C to the boiling point of the solvent used. The reaction time is usually about 1 hour to 24 hours, although it is desirable to follow the reaction by gas chromatography (GC) or silica gel thin layer chromatography (TLC) in terms of yield and complete the reaction. Intermediate 2 can be obtained from the reaction mixture by a conventional aqueous work-up. The obtained intermediate 2 can be purified according to conventional methods such as distillation, chromatography, and recrystallization, if necessary.

[0065] In the third step, intermediate 2 obtained in the second step is subjected to hydrolysis using a base to hydrolyze only the aromatic ester bond. Solution This is the process for obtaining monomer A-1.

[0066] The reaction can be carried out by a known organic synthesis method. Specifically, the intermediate 2 is dissolved in 1,4-dioxane, THF, or the like, and a base is added dropwise to carry out the reaction. Examples of the base used in the reaction include aqueous solutions of inorganic bases such as sodium hydroxide, potassium hydroxide, and potassium carbonate. The reaction temperature is preferably in the range of ice-cooling to 60°C. The reaction time is usually about 2 to 12 hours, although it is desirable in terms of yield to follow the reaction by gas chromatography (GC) or silica gel thin layer chromatography (TLC) to complete the reaction. After the reaction is completed, an acid is added to stop the reaction, and examples of the acid used include aqueous solutions of hydrochloric acid, sulfuric acid, and nitric acid. The reaction is preferably stopped under ice-cooling. Monomer A-1 can be obtained from the reaction mixture by ordinary aqueous work-up. The obtained monomer A-1 can be purified according to ordinary methods such as distillation, chromatography, and recrystallization, if necessary.

[0067] Specific examples of the repeating unit A represented by the above formulas (A-1) and (A-2) include, but are not limited to, the following structures. A is the same as above.

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] [Repeating unit B that generates acid upon exposure] The polymer of the present invention contains a repeating unit that generates an acid upon exposure (hereinafter, also referred to as repeating unit B). The repeating unit B is at least one of a repeating unit represented by the following formula (B-1) (hereinafter, also referred to as repeating unit B1), a repeating unit represented by the following formula (B-2) (hereinafter, also referred to as repeating unit B2), a repeating unit represented by the following formula (B-3) (hereinafter, also referred to as repeating unit B3), and a repeating unit represented by the following formula (B-4) (hereinafter, also referred to as repeating unit B4). [ka]

[0082] In formulas (B-1) to (B-4), R A is the same as above. Z 1 is a single bond or a phenylene group. 2 is a single bond, -C(=O)-OZ 21 -, -C(=O)-NH-Z 21 -or-OZ 21 -It is. 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 hydroxyl group. 3 is a single bond, a phenylene group, a naphthylene group, or (main chain)-C(=O)-OZ 31 -It is. 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, a methylene group, or -Z 41 -C(=O)-O-. Z 41 Z is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom, an ether bond, or an ester bond. 5 is a single bond, a methylene group, an ethylene group, a phenylene group substituted with a trifluoromethyl group, a phenylene group, a fluorinated phenylene group, -C(=O)-OZ 51 -, -C(=O)-NH-Z51 -or-OZ 51 -It is. 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group.

[0083] Z 21 , Z 31 and Z 51 The aliphatic hydrocarbylene group represented by the formula (A-1) may be linear, branched, or cyclic. A1 Examples of the examples are similar to those given in the description of .

[0084] 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. [ka] (In the formula, the dashed lines represent bonds.)

[0085] In formula (B-1), R 21 and R 22 R is each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22The hydrocarbyl group represented by the formula (1) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbyl groups such as cyclohexenyl; aryl groups such as phenyl, naphthyl, and thienyl; aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these groups, with aryl groups being preferred. In addition, some of the hydrogen atoms of the hydrocarbyl group may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and a heteroatom-containing group such as an oxygen atom, a sulfur atom or a nitrogen atom may be present between the carbon atoms of these groups, and as a result, the group may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0086] 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 formulas. [ka]

[0087] Examples of the cation of the repeating unit B1 include, but are not limited to, those shown below. A is the same as above. [ka]

[0088] [ka]

[0089] [ka]

[0090] [ka]

[0091] In formula (B-1), M - is a non-nucleophilic counterion. - Examples of the non-nucleophilic counter ion represented by the formula (I) 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 acid ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion and bis(perfluorobutylsulfonyl)imide ion; and methide acid ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0092] Further, examples of the non-nucleophilic counter ion include a sulfonate anion represented by the following formula (B-1-1) in which the α-position is substituted with a fluorine atom, and a sulfonate anion represented by the following formula (B-1-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group. [ka]

[0093] In formula (B-1-1), R 23 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). 105 Examples of the hydrocarbyl group represented by the formula (I) include the same as those described below.

[0094] In formula (B-1-2), R 24 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, or an aryloxy group having 6 to 20 carbon atoms, and may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl group and the hydrocarbylcarbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). 105 Examples of the hydrocarbyl group represented by the formula (I) include the same as those described below.

[0095] Specific examples of the sulfonate anion represented by the non-nucleophilic counter ion include, but are not limited to, those shown below. In the following formula, Q 3 is a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms, and Ac is an acetyl group. [ka]

[0096] [ka]

[0097] [ka]

[0098] [ka]

[0099] [ka]

[0100] [ka]

[0101] [ka]

[0102] [ka]

[0103] In formula (B-2), L 11 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.

[0104] In formula (B-2), 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, each of Rf is preferably a fluorine atom. 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. 3 and Rf 4 At least one of these is preferably a trifluoromethyl group.

[0105] In the formula (B-2), c is an integer of 0 to 3, with 1 being preferred.

[0106] Specific examples of the anion of the repeating unit represented by formula (B-2) include, but are not limited to, those shown below. In the following formula, R A is the same as above

[0107] [ka]

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] [ka]

[0113] In formula (B-3), L 11 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.

[0114] In formula (B-3), Rf 3 and Rf 4Rf are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4 At least one of these is preferably a trifluoromethyl group.

[0115] In formula (B-3), c is an integer of 0 to 3, with 1 being preferred.

[0116] Specific examples of the anion of the repeating unit represented by formula (B-3) include, but are not limited to, those shown below. In the following formula, R A is the same as above

[0117] [ka]

[0118] [ka]

[0119] [ka]

[0120] Specific examples of the anion of the repeating unit represented by formula (B-4) include, but are not limited to, those shown below. In the following formula, R A is the same as above

[0121] [ka]

[0122] In formulas (B-2) to (B-4), A +is an onium cation. Examples of the onium cation include ammonium cation, sulfonium cation, and iodonium cation. 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) and an iodonium cation represented by the following formula (cation-2). [ka]

[0123] In formulas (cation-1) and (cation-2), R 11 ~R 15 are each independently a hydrocarbyl group having 1 to 30 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 such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbyl groups such as cyclohexenyl; aryl groups such as phenyl, naphthyl, and thienyl; aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these groups, with aryl groups being preferred. In addition, some of the hydrogen atoms of the hydrocarbyl group may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and a heteroatom-containing group such as an oxygen atom, a sulfur atom or a nitrogen atom may be present between the carbon atoms of these groups, and as a result, the group may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0124] Also, R11 and R 12 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: [ka] (In the formula, the dashed line represents R 13 It is a combination with .)

[0125] Examples of the sulfonium cation represented by formula (cation-1) include, but are not limited to, those shown below.

[0126] [ka]

[0127] [ka]

[0128] [ka]

[0129] [ka]

[0130] [ka]

[0131] [ka]

[0132] [ka]

[0133]

change

[0134]

change

[0135]

change

[0136]

change

[0137]

change

[0138]

change

[0139]

change

[0140]

change

[0141]

change

[0142]

change

[0143]

change

[0144] [ka]

[0145] Examples of the iodonium cation represented by formula (cation-2) include, but are not limited to, those shown below. [ka]

[0146] Specific structures of the repeating units represented by formulae (B-1) to (B-4) include any combination of the above-mentioned anions and cations.

[0147] As the repeating unit B, the repeating units B2, B3 and B4 are preferred from the viewpoint of controlling acid diffusion, the repeating units B2 and B4 are more preferred from the viewpoint of the acid strength of the generated acid, and the repeating unit B2 is more preferred from the viewpoint of solvent solubility.

[0148] The polymer of the present invention is characterized in that it contains a repeating unit A having an acid labile group containing a phenolic hydroxyl group and a repeating unit B that generates an acid upon exposure. By containing a repeating unit that generates an acid upon exposure in the base polymer, it is possible to suppress excessive acid diffusion, particularly in the case where the acid generated after exposure is an anion-bound type bonded to the main chain of the base polymer, and it is considered that the secondary electrons generated at the sensitized site contribute to the decomposition of the cation without diffusing. In addition, the repeating unit having an acid labile group containing a phenolic hydroxyl group contributes to the change in solubility in the developer in the deprotection reaction after exposure, and particularly contributes to the sensitization effect of generating secondary electrons from EUV light. When the acid labile unit and the sensitizing unit are introduced individually into the base polymer, if the amount of the acid labile unit introduced is increased to improve the contrast, the amount of the sensitizing unit introduced will decrease, and the amount of secondary electrons generated will decrease, resulting in low sensitivity. Conversely, if the sensitizing unit is increased, the amount of secondary electrons generated will increase, but the amount of the acid labile unit introduced in the base polymer will decrease, resulting in a decrease in the dissolution contrast. From this perspective, the acid labile units and sensitizing units in the base polymer can be increased simultaneously by introducing repeating units having an acid labile group, including a phenolic hydroxyl group. This synergistic effect can simultaneously achieve high sensitivity and high contrast, enabling the formation of patterns with small LWR for line patterns and small CDU for hole patterns.

[0149] [Repeating units a1, a2] The polymer of the present invention may further contain at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (a-1) (hereinafter also referred to as a repeating unit a1) and a repeating unit represented by the following formula (a-2) (hereinafter also referred to as a repeating unit a2). [ka]

[0150] In formulas (a-1) and (a-2), R A , Z A , Z B , R b is the same as above. p is an integer of 0 to 4. XA and X B each independently represents an acid labile group not containing a fluorine-containing aromatic ring.

[0151] In formulas (a-1) and (a-2), X A and X B Examples of the acid labile group represented by the formula (I) include those described in JP-A-2013-80033 and JP-A-2013-83821.

[0152] Typically, the acid labile group includes those represented by the following formulae (AL-1) to (AL-3). [ka] (In the formula, the dashed lines represent bonds.)

[0153] 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, and 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.

[0154] In formula (AL-1), a is an integer of 0 to 10, and an integer of 1 to 5 is preferable.

[0155] 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 preferable, and an alicyclic ring is particularly preferable.

[0156] 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 to form, together with the carbon atom to which they are bonded, a ring having 3 to 20 carbon atoms. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0157] Examples of the repeating unit a1 include, but are not limited to, those shown below. In the following formula, R A and X A is the same as above. [ka]

[0158] [ka]

[0159] Examples of the repeating unit a2 include, but are not limited to, those shown below. In the following formula, R A and X B is the same as above.

[0160] [ka]

[0161] [Repeating unit C having a phenolic hydroxy group] The polymer of the present invention contains a repeating unit having a phenolic hydroxy group (hereinafter, also referred to as repeating unit C). As the repeating unit C, one represented by the following formula (C-1) is preferable. [ka]

[0162] In formula (C-1), R A is the same as above. Z B is a single bond or (main chain) -C(=O)-O-. R b1 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. m is an integer of 1 to 4, k is an integer of 0 to 3, and m+k is an integer of 4 or less.

[0163] R b1 The hydrocarbyl group represented by the formula (A-1) may be saturated or unsaturated and may be linear, branched, or cyclic. 1b Specific examples of the hydrocarbyl moiety of the hydrocarbyloxy group and the hydrocarbylcarbonyl group include R 1b Examples of the examples are similar to those given in the description of .

[0164] Examples of the repeating unit C include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0165] [ka]

[0166] [ka]

[0167] [Repeating unit D] The polymer of the present invention may further contain a repeating unit represented by the following formula (D-1) (hereinafter also referred to as repeating unit D). [ka]

[0168] In the formula, R A and Z A is the same as above. Y A is a hydrogen atom, or a polar group containing at least one structure selected from a hydroxy group, a cyano group, a carbonyl group, a carboxy group, an ether bond, an ester bond, a sulfonate ester bond, a sulfonamide bond, a carbonate bond, a lactone ring, a sultone ring, a sulfur atom, and a carboxylic acid anhydride.

[0169] Above Y A may be a hydrogen atom, or a polar group containing at least one structure selected from a hydroxy group other than a phenolic hydroxy group, a cyano group, a carbonyl group, a carboxy group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, and a carboxylic acid anhydride.

[0170] Examples of the repeating unit D include, but are not limited to, those shown below. In the following formula, R A is the same as above.

[0171] [ka]

[0172] [ka]

[0173] [ka]

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] [ka]

[0178] [ka]

[0179] [Repeating unit E] The polymer of the present invention may further comprise a repeat unit E derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or a derivative thereof. Monomers that provide the repeat unit E include, but are not limited to, those shown below. [ka]

[0180] [Repeating unit F] The polymers of the present invention may further comprise repeat units F derived from indane, vinylpyridine or vinylcarbazole.

[0181] In the polymer of the present invention, the content ratios of repeating units A, a1, a2, B, C, D, E, and F are preferably 0 < A < 1.0, 0 ≦ a1 ≦ 0.8, 0 ≦ a2 ≦ 0.8, 0 < B < 1.0, 0 ≦ C < 1.0, 0 ≦ D ≦ 0.8, 0 ≦ E ≦ 0.8, and 0 ≦ F ≦ 0.4, more preferably 0.05 ≦ A ≦ 0.9, 0 ≦ a1 ≦ 0.7, 0 ≦ a2 ≦ 0.7, 0 ≦ a1 + a2 ≦ 0.7, 0.01 ≦ B ≦ 0.4, 0.09 ≦ C ≦ 0.55, 0 ≦ D ≦ 0.7, 0 ≦ E ≦ 0.7, and 0 ≦ F ≦ 0.3, and still more preferably 0.1 ≦ A ≦ 0.8, 0 ≦ a1 ≦ 0.6, 0 ≦ a2 ≦ 0.6, 0 ≦ a1 + a2 ≦ 0.4, 0.1 ≦ B ≦ 0.45, 0.1 ≦ C ≦ 0.45, 0 ≦ D ≦ 0.6, 0 ≦ E ≦ 0.6, and 0 ≦ F ≦ 0.2.

[0182] When at least one of the repeating units B is selected from repeating units B1 to B4, B = B1 + B2 + B3 + B4. Also, A + a1 + a2 + B + C + D + E + F = 1.

[0183] The weight average molecular weight (Mw) of the polymer is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. If Mw is within this range, sufficient etching resistance can be obtained, and there is no risk of a decrease in resolution due to the inability to ensure the difference in dissolution rate before and after exposure. In the present invention, Mw is a polystyrene equivalent measurement value by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent.

[0184] Furthermore, since the influence of the molecular weight distribution (Mw / Mn) of the polymer tends to increase as the pattern rules are miniaturized, in order to obtain a resist composition suitably used for fine pattern dimensions, Mw / Mn is preferably narrowly dispersed at 1.0 to 2.0. If it is within the above range, there are few low molecular weight and high molecular weight polymers, and there is no risk of foreign matter being seen on the pattern or the pattern shape deteriorating after exposure.

[0185] To synthesize the polymer, for example, a monomer that provides the repeating unit described above can be polymerized in an organic solvent by adding a radical polymerization initiator and heating the resulting mixture.

[0186] Examples of the organic solvent 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, and 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.

[0187] The polymerization initiator may be added to the monomer solution and then fed to the reaction vessel, or an initiator solution may be prepared separately from the monomer solution and then fed to the reaction vessel independently. Since there is a possibility that the polymerization reaction proceeds due to radicals generated from the initiator during the waiting time, resulting in the formation of a super-polymer, it is preferable to prepare the monomer solution and the initiator solution independently and dropwise feed them from the viewpoint of quality control. The acid labile group introduced into the monomer may be used as is, or may be protected or partially protected after polymerization. In addition, a known chain transfer agent such as dodecyl mercaptan or 2-mercaptoethanol may be used in combination to adjust the molecular weight. In this case, the amount of these chain transfer agents added is preferably 0.01 to 20 mol% based on the total amount of monomers to be polymerized.

[0188] In the case of a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid, such as an ethoxyethoxy group, 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.

[0189] When hydroxystyrene or hydroxyvinylnaphthalene is copolymerized, hydroxystyrene or hydroxyvinylnaphthalene may be polymerized by heating with another monomer in an organic solvent after adding a radical polymerization initiator, or acetoxystyrene or acetoxyvinylnaphthalene may be used and, after polymerization, the acetoxy group may be deprotected by alkaline hydrolysis to give polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0190] As the base for the alkaline hydrolysis, ammonia water, triethylamine, etc. can be used. The reaction temperature is preferably −20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0191] The amount of each monomer in the monomer solution may be appropriately set so as to obtain the preferred content ratio of the repeating units described above.

[0192] Regarding the polymer obtained by the above-mentioned production method, a reaction solution obtained by a polymerization reaction may be used as the final product, or a powder obtained through a purification step such as a reprecipitation method in which a polymerization solution is added to a poor solvent to obtain a powder may be handled as the final product. However, from the viewpoint of work efficiency and quality stabilization, it is preferable to handle a polymer solution obtained by dissolving the powder obtained by the purification step in a solvent as the final product.

[0193] Specific examples of the solvent used in this case include ketones such as cyclohexanone and methyl-2-n-pentyl ketone, as described in paragraphs

[0144] to

[0145] of JP-A-2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 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. ethers such as ether; 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, propylene glycol mono tert-butyl ether acetate, etc.; lactones such as GBL; alcohols such as diacetone alcohol (DAA); high-boiling alcohol solvents such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, 1,3-butanediol, etc.; and mixed solvents thereof.

[0194] The concentration of the polymer in the polymer solution is preferably from 0.01 to 30% by mass, more preferably from 0.1 to 20% by mass.

[0195] The reaction solution or polymer solution is preferably filtered through a filter, which is effective in stabilizing the quality since it can remove foreign matter or gel that may cause defects.

[0196] The material of the filter used in the filter filtration includes fluorocarbon, cellulose, nylon, polyester, and hydrocarbon materials, but in the filtration process of the resist composition, a filter formed of a fluorocarbon, so-called Teflon (registered trademark), a hydrocarbon such as polyethylene or polypropylene, or nylon is preferred. The pore size of the filter can be appropriately selected according to the target cleanliness, but is preferably 100 nm or less, more preferably 20 nm or less. In addition, these filters may be used alone or in combination of multiple filters. The filtration method may be to pass the solution through only once, but it is more preferable to circulate the solution and perform filtration multiple times. The filtration process can be performed in any order and number of times in the polymer production process, but it is preferable to filter the reaction solution after the polymerization reaction, the polymer solution, or both.

[0197] The polymer may include two or more polymers having different composition ratios, Mw, and molecular weight distributions.

[0198] Furthermore, the present invention can provide a resist composition containing the above-mentioned polymer, and specifically, can provide the following chemically amplified resist composition.

[0199] [Chemically amplified resist composition] The chemically amplified resist composition of the present invention comprises (P) Base polymer (G) Quencher (H) Organic Solvent Including, if necessary, (I) a photoacid generator other than the photoacid generator bonded to the base polymer chain; (J) a nitrogen-containing quencher, and (K) Surfactants that are insoluble or poorly soluble in water and soluble in an alkaline developer, and / or surfactants that are insoluble or poorly soluble in water and an alkaline developer and optionally, (L) Other ingredients may include.

[0200] [(G)Quencher] The (G) quencher includes an onium salt represented by the following formula (1) or (2). [ka]

[0201] In formula (1), R q1 is a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, except for those in which the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group. q2 is a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom.

[0202] R q1 Specific examples of the hydrocarbyl group represented by the formula (1) include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, a tricyclo[5.2.1.0 2,6 ] cyclic saturated hydrocarbyl groups such as decanyl group and adamantyl group; and aryl groups such as phenyl group, naphthyl group and anthracenyl group. In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms and halogen atoms, or some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms and nitrogen atoms, and as a result, they may contain hydroxy groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydrides, haloalkyl groups and the like.

[0203] R q2 Specific examples of the hydrocarbyl group represented by the formula: q1 In addition to the specific examples of the substituents given above, examples of the substituents include fluorinated alkyl groups such as a trifluoromethyl group and a trifluoroethyl group, and fluorinated aryl groups such as a pentafluorophenyl group and a 4-trifluoromethylphenyl group.

[0204] Examples of the anion of the onium salt represented by formula (1) include, but are not limited to, those shown below.

[0205] [ka]

[0206] [ka]

[0207] Examples of the anion of the onium salt represented by formula (2) include, but are not limited to, those shown below.

[0208] [ka]

[0209] [ka]

[0210] In formulas (1) and (2), Mq + is an onium cation. The onium cation is preferably one represented by the following formula (cation-1), (cation-2) or (cation-3). [ka]

[0211] Regarding formulae (cation-1) and (cation-2), A in formulae (B-2) to (B-4) + The same as above can be mentioned. (cation-3) R 16 ~R 19 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. 16 and R 17 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded. The hydrocarbyl group is represented by R 11 ~R 15 Examples of the examples are similar to those given in the description of .

[0212] Mq + In the onium cation represented by the formula: embedded image Examples of the ammonium cation represented by (cation-3) include, but are not limited to, those shown below. [ka]

[0213] Specific examples of the onium salt represented by formula (1) or (2) include any combination of the above-mentioned anions and cations. These onium salts can be easily prepared by ion exchange reaction using known organic chemical methods. For the ion exchange reaction, refer to, for example, JP-A-2007-145797.

[0214] The onium salt represented by formula (1) or (2) acts as a quencher in the chemically amplified resist composition of the present invention. This is because the counter anion of each onium salt is a conjugate base of a weak acid. The weak acid here means an acidity that is not capable of deprotecting the acid labile group of the acid labile group-containing unit used in the base polymer.

[0215] The onium salt represented by formula (1) or (2) functions as a quencher when used in combination with an onium salt-type photoacid generator having a conjugate base of a strong acid such as sulfonic acid fluorinated at the α-position as a counter anion. That is, when an onium salt generating a strong acid such as sulfonic acid fluorinated at the α-position is mixed with an onium salt generating a weak acid such as non-fluorinated sulfonic acid or carboxylic acid, when the strong acid generated from the photoacid generator by irradiation with high energy rays collides with an onium salt having an unreacted weak acid anion, the weak acid is released by salt exchange to generate an onium salt having a strong acid anion. In this process, the strong acid is exchanged for a weak acid with a lower catalytic activity, and the acid is apparently deactivated, thereby controlling acid diffusion.

[0216] Here, when the photoacid generator that generates a strong acid is an onium salt, the strong acid generated by irradiation with high energy rays can be exchanged for a weak acid as described above, but on the other hand, it is considered that the weak acid generated by irradiation with high energy rays collides with the onium salt that generates the unreacted strong acid and is unlikely to undergo salt exchange. This is due to the phenomenon that the onium cation is more likely to form an ion pair with the anion of the strong acid.

[0217] When the onium salt type quencher (G) contains an onium salt represented by formula (1) or (2), the content is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, relative to 80 parts by mass of the base polymer (P). If the onium salt type quencher of the component (G) is within the above range, the resolution is good and the sensitivity is not significantly reduced, which is preferable. The onium salt represented by formula (1) or (2) may be used alone or in combination of two or more kinds.

[0218] [(H) Organic solvent] The organic solvent of the component (H) is not particularly limited as long as it can dissolve the above-mentioned components and the components described below. Examples of such organic solvents include ketones such as cyclopentanone, 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; ketoalcohols such as DAA; ethers such as PGME, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; 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 monotert-butyl ether acetate; lactones such as GBL, and mixed solvents thereof.

[0219] When a polymer containing an acetal-based acid labile group is used, a high-boiling alcohol solvent, specifically, diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, 1,3-butanediol, or the like can be added to accelerate the deprotection reaction of the acetal.

[0220] Of these organic solvents, 1-ethoxy 2-propanol, PGMEA, cyclohexanone, GBL, DAA, ethyl lactate, and mixed solvents thereof are preferred, as they have particularly excellent solubility for the base polymer of component (P).

[0221] The amount of the organic solvent used is preferably 200 to 5,000 parts by mass, and more preferably 400 to 3,000 parts by mass, based on 80 parts by mass of the base polymer (P). The organic solvent (H) may be used alone or in combination of two or more kinds.

[0222] [(I) Photoacid generator other than photoacid generator bound to base polymer chain] The chemically amplified resist composition of the present invention may contain a photoacid generator other than the photoacid generator bonded to the base polymer chain as component (I). The photoacid generator is not particularly limited as long as it is a compound that generates an acid upon exposure to high-energy radiation. A suitable photoacid generator is one represented by the following formula (3). [ka]

[0223] In formula (3), R 101 , R 102 and R 103 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 101 , R 102 and R 103 Any two of the above may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 11 ~R 15 Examples of the cation of the sulfonium salt represented by formula (3) include the same as those exemplified in the description of formula (1).

[0224] In formula (3), X - is an anion selected from the following formulas (3A) to (3D). [ka]

[0225] In formula (3A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 105Examples of the above-mentioned properties include those described later in the description of the above.

[0226] The anion represented by formula (3A) is preferably one represented by the following formula (3A'). [ka]

[0227] In formula (3A'), R 104 R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 105 is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, or the like, and more preferably an oxygen atom. In order to obtain high resolution in the formation of a fine pattern, the hydrocarbyl group is preferably one having 6 to 30 carbon atoms.

[0228] R 105 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosanyl; cyclic saturated hydrocarbyl groups such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecanyl, tetracyclododecanylmethyl, and dicyclohexylmethyl; unsaturated aliphatic hydrocarbyl groups such as allyl and 3-cyclohexenyl; aryl groups such as phenyl, 1-naphthyl, and 2-naphthyl; and aralkyl groups such as benzyl and diphenylmethyl. 105As the heteroatom, an aliphatic group is preferable. In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, they may contain hydroxy groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate groups, lactone rings, sultone rings, carboxylic acid anhydrides, haloalkyl groups, and the like. Examples of hydrocarbyl groups containing heteroatoms include tetrahydrofuryl groups, methoxymethyl groups, ethoxymethyl groups, methylthiomethyl groups, acetamidomethyl groups, trifluoroethyl groups, (2-methoxyethoxy)methyl groups, acetoxymethyl groups, 2-carboxy-1-cyclohexyl groups, 2-oxopropyl groups, 4-oxo-1-adamantyl groups, and 3-oxocyclohexyl groups.

[0229] Synthesis of sulfonium salts having an anion represented by formula (3A') is described in detail in JP-A-2007-145797, JP-A-2008-106045, JP-A-2009-7327, JP-A-2009-258695, etc. In addition, sulfonium salts described in JP-A-2010-215608, JP-A-2012-41320, JP-A-2012-106986, JP-A-2012-153644, etc. are also preferably used.

[0230] The anion represented by formula (3A) is, for example, M - Examples of the above-mentioned examples include, but are not limited to, those listed above.

[0231] In formula (3B), R fb1 and R fb2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 105 Examples of the same as those given in the explanation of R fb1 and Rfb2 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 means that the groups (-CF2-SO2-N - -SO2-CF2-) may form a ring, in which case, R fb1 and R fb2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0232] In formula (3C), R fc1 , R fc2 and R fc3 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 105 Examples of the same as those given in the explanation of R fc1 , R fc2 and R fc3 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 means that the groups (-CF2-SO2-C - -SO2-CF2-) may form a ring, in which case, R fc1 and R fc2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0233] In formula (3D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 105 Examples of the examples are similar to those given in the description of .

[0234] The synthesis of a sulfonium salt having an anion represented by formula (3D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

[0235] Examples of the anion represented by formula (3D) include, but are not limited to, those shown below. [ka]

[0236] Although the photoacid generator having the anion represented by formula (3D) does not have a fluorine atom at the α-position of the sulfo group, it has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave the acid labile group in the base polymer, and can therefore be used as a photoacid generator.

[0237] As a photoacid generator other than the photoacid generator bonded to the base polymer chain of the component (I), a compound represented by the following formula (4) is also preferred. [ka]

[0238] In formula (4), R 201 and R 202 R is each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 201 , R 202 and R 203 Any two of may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring may be any of the groups represented by R 21 and R 22 are bonded to each other to form a ring together with the sulfur atom to which they are bonded.

[0239] R 201 and R 202The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6 ] cyclic saturated hydrocarbyl groups such as decanyl group and adamantyl group; and aryl groups such as phenyl group, naphthyl group and anthracenyl group. In addition, some of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom and halogen atom, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom and nitrogen atom, and as a result, they may contain hydroxy group, cyano group, carbonyl group, ether bond, ester bond, sulfonic acid ester bond, carbonate group, lactone ring, sultone ring, carboxylic acid anhydride, haloalkyl group, etc.

[0240] R 203The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups such as methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, and heptadecane-1,17-diyl; cyclopentanediyl, cyclohexanediyl, and cyclohexanediyl. Examples of the alkyl group include cyclic saturated hydrocarbylene groups such as a hexanediyl group, a norbornanediyl group, and an adamantanediyl group; and arylene groups such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group, an isobutylphenylene group, a sec-butylphenylene group, a tert-butylphenylene group, a naphthylene group, a methylnaphthylene group, an ethylnaphthylene group, an n-propylnaphthylene group, an isopropylnaphthylene group, an n-butylnaphthylene group, an isobutylnaphthylene group, a sec-butylnaphthylene group, and a tert-butylnaphthylene group. In addition, a portion of the hydrogen atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a portion of the carbon atoms of these groups may be substituted with a heteroatom-containing group such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., so that the group may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic anhydride, a haloalkyl group, etc. As the heteroatom, an oxygen atom is preferable.

[0241] In formula (4), L A is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a single bond, an ether bond, or a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 203Examples of the hydrocarbylene group represented by the formula (I) include the same as those exemplified above.

[0242] In formula (4), X a , X b , X c and X d are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. a , X b , X c and X d At least one of the groups is a fluorine atom or a trifluoromethyl group.

[0243] The photoacid generator represented by formula (4) is preferably one represented by the following formula (4'). [ka]

[0244] In formula (4'), L A is the same as above. X e R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 105 Examples of the cations are the same as those exemplified in the explanation of 1. Each of x and y is independently an integer of 0 to 5, and z is an integer of 0 to 4.

[0245] Examples of the photoacid generator represented by formula (4) include the same as those exemplified as the photoacid generator represented by formula (4) in JP2017-026980A.

[0246] Among the other photoacid generators, those containing an anion represented by formula (3A') or (3D) are particularly preferred because of their small acid diffusion and excellent solubility in resist solvents, and those containing an anion represented by formula (4') are particularly preferred because of their extremely small acid diffusion.

[0247] As other acid generators, onium salts represented by the following formula (5-1) or (5-2) can also be used. [ka]

[0248] In formulas (5-1) and (5-2), r is an integer satisfying 1≦r≦3. s and t are integers satisfying 1≦s≦5, 0≦t≦3, and 1≦s+t≦5. s is preferably an integer satisfying 1≦s≦3, more preferably 2 or 3. t is preferably an integer satisfying 0≦t≦2.

[0249] In formulas (5-1) and (5-2), X BI represents an iodine atom or a bromine atom, and when s is 2 or more, they may be the same or different.

[0250] In formulas (5-1) and (5-2), L 11 is a single bond, an ether bond or an ester bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched or cyclic.

[0251] In formulas (5-1) and (5-2), L 12 represents a single bond or a divalent linking group having 1 to 20 carbon atoms when r is 1, and represents a trivalent or tetravalent linking group having 1 to 20 carbon atoms when r is 2 or 3, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0252] In formulas (5-1) and (5-2), R 401is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 10 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group, or an ether bond, or -NR 401A -C(=O)-R 401B or -NR 401A -C(=O)-OR 401B It is.

[0253] R 401A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms.

[0254] R 401B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms.

[0255] The aliphatic hydrocarbyl group may be saturated or unsaturated and may be linear, branched or cyclic. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbyloxycarbonyl group, saturated hydrocarbylcarbonyl group and saturated hydrocarbylcarbonyloxy group may be linear, branched or cyclic.

[0256] When t is 2 or more, each R 401 may be the same or different from each other.

[0257] Of these, R 401Examples include hydroxyl groups, -NR 401A -C(=O)-R 401B , -NR 401A -C(=O)-OR 401B , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group, and the like are preferred.

[0258] In formulas (5-1) and (5-2), Rf 11 ~Rf 14 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, at least one of which is a fluorine atom or a trifluoromethyl group. 11 and Rf 12 may combine to form a carbonyl group. 13 and Rf 14 are preferably both fluorine atoms.

[0259] In formulas (5-1) and (5-2), R 402 , R 403 , R 404 , R 405 and R 406 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms.

[0260] In addition, some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the carbon atoms of these groups may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate group, or a sulfonate ester bond.

[0261] Also, R 402 , R 403 and R404 Any two of these may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is as defined in the explanation of formula (3), 101 and R 102 and the like can be bonded to form a ring together with the sulfur atom to which they are bonded.

[0262] Examples of the cation of the sulfonium salt represented by formula (5-1) include the same as those exemplified as the sulfonium cation represented by formula (cation-1). Examples of the cation of the iodonium salt represented by formula (5-2) include the same as those exemplified as the iodonium cation represented by formula (cation-2).

[0263] Examples of the anions of the onium salts represented by formulae (5-1) and (5-2) include those exemplified as the anions of the onium salts represented by formulae (5-1) and (5-2) in JP 2018-197853 A, as well as those in which the iodine atom of the anions is replaced with a bromine atom.

[0264] When a photoacid generator other than the photoacid generator bonded to the base polymer chain of the component (I) is contained, the content is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 20 parts by mass, relative to 80 parts by mass of the (P) base polymer. If the amount of the photoacid generator other than the photoacid generator bonded to the base polymer chain of the component (I) is within the above range, the resolution is good and there is no risk of problems with foreign matter occurring after development of the resist film or during stripping, which is preferable. The photoacid generator other than the photoacid generator bonded to the base polymer chain of the component (I) can be used alone or in combination of two or more.

[0265] [(J) Nitrogen-containing quencher] The chemically amplified resist composition of the present invention may further contain a nitrogen-containing quencher. In the present invention, the nitrogen-containing quencher is a material that traps the acid generated by the photoacid generator in the chemically amplified resist composition to prevent the acid from diffusing into unexposed areas, thereby forming a desired pattern.

[0266] Examples of the nitrogen-containing quencher of component (J) 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. Also included are compounds in which a primary or secondary amine is protected with a carbamate group, such as the compounds described in JP 3790649 A.

[0267] In addition, 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 the unexposed area, and functions as a so-called photodegradable base in the exposed area, losing its quenching ability by neutralization with the acid generated by itself. By using a photodegradable base, the contrast between the exposed area and the unexposed area can be further enhanced. For example, JP-A-2009-109595 and JP-A-2012-46501 can be referred to for the photodegradable base.

[0268] When the nitrogen-containing quencher of the component (J) is contained, its content is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass, relative to 80 parts by mass of the base polymer (P). The nitrogen-containing compound can be used alone or in combination of two or more kinds.

[0269] [(K) A surfactant which is insoluble or poorly soluble in water and soluble in an alkaline developer, and / or a surfactant which is insoluble or poorly soluble in water and an alkaline developer] The chemically amplified resist composition of the present invention may further contain (K) a surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer, and / or a surfactant that is insoluble or poorly soluble in water and an alkaline developer. Examples of such surfactants include those described in JP2010-215608A and JP2011-16746A.

[0270] Among the surfactants described in the above publication, preferred surfactants that are insoluble or poorly 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 an oxetane ring-opening polymer represented by the following formula (surf-1): [ka]

[0271] Here, R, Rf, A, B, C, m, and n in the above formula (surf-1) apply only to formula (surf-1), regardless of the above description. R is a divalent to tetravalent aliphatic group having 2 to 6 carbon atoms. As the aliphatic group, divalent ones include an ethylene group, a 1,4-butylene group, a 1,2-propylene group, a 2,2-dimethyl-1,3-propylene group, a 1,5-pentylene group, etc., and trivalent or tetravalent ones include the following. [ka] (In the formula, the dashed lines represent bonds and are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.)

[0272] Among these, a 1,4-butylene group, a 2,2-dimethyl-1,3-propylene group, and the like are preferable.

[0273] 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 constituent units in the formula (surf-1) is not specified, and they may be bonded in blocks or randomly. The production of a partially fluorinated oxetane ring-opening polymer surfactant is described in detail in the specification of U.S. Pat. No. 5,650,483.

[0274] A surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer has a function of reducing water penetration and leaching by orienting on the surface of the resist film when a resist protective film is not used in ArF immersion exposure. Therefore, it is useful for suppressing the elution of water-soluble components from the resist film and reducing damage to the exposure device, and is also useful because it is soluble during alkaline aqueous solution development after exposure or PEB and is unlikely to become a foreign matter that causes defects. Such surfactants are insoluble or poorly soluble in water and soluble in an alkaline developer, and are polymer-type surfactants, also called hydrophobic resins, and are particularly preferred for their high water repellency and improved water slipping properties.

[0275] Such polymeric surfactants include those containing at least one type selected from the repeating units represented by the following formulas (6A) to (6E). [ka]

[0276] In formulas (6A) to (6E), R B is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 R is -CH2-, -CH2CH2-, -O- or two -H separated from each other. s1 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. s2R is a single bond or a linear or branched hydrocarbylene group having 1 to 5 carbon atoms. s3 R are each independently a hydrogen atom, a hydrocarbyl group or a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group. s3 When R is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond (-O-) or a carbonyl group (-C(=O)-) may be present between the carbon-carbon bonds. s4 is a (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group having 1 to 20 carbon atoms. u is an integer of 1 to 3. s5 each independently represents a hydrogen atom or a group represented by the formula -C(=O)-OR sa R sa R is a fluorinated hydrocarbyl group having 1 to 20 carbon atoms. s6 is a hydrocarbyl group or a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, and an ether bond (-O-) or a carbonyl group (-C(=O)-) may be present between the carbon-carbon bonds.

[0277] R s1 The hydrocarbyl group represented by the formula (I) is preferably a saturated hydrocarbyl group, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl. Among these, those having 1 to 6 carbon atoms are preferred.

[0278] R s2 The hydrocarbylene group represented by the formula (I) is preferably a saturated hydrocarbylene group, which may be linear, branched or cyclic. Specific examples thereof include a methylene group, an ethylene group, a propylene group, a butylene group and a pentylene group.

[0279] R s3 or Rs6 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include saturated hydrocarbyl groups, and aliphatic unsaturated hydrocarbyl groups such as alkenyl groups and alkynyl groups, with saturated hydrocarbyl groups being preferred. As the saturated hydrocarbyl group, R s1 In addition to the examples of the hydrocarbyl group represented by the formula (I), examples of the hydrocarbyl group represented by the formula (I) include an n-undecyl group, an n-dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group. s3 or R s6 The fluorinated hydrocarbyl group represented by the formula (I) includes a group in which some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbyl group described above are replaced with fluorine atoms. As described above, an ether bond (-O-) or a carbonyl group (-C(=O)-) may be contained between these carbon-carbon bonds.

[0280] R s3 Examples of the acid labile group represented by the formula (AL-1) to (AL-3) include the groups represented by the formulas (AL-1) to (AL-3) above, trialkylsilyl groups in which each alkyl group has 1 to 6 carbon atoms, and oxo group-containing alkyl groups having 4 to 20 carbon atoms.

[0281] R s4 The (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group represented by the formula (1) may be linear, branched, or cyclic, and specific examples thereof include groups in which u hydrogen atoms have been removed from the aforementioned hydrocarbyl groups or fluorinated hydrocarbyl groups.

[0282] R saThe fluorinated hydrocarbyl group represented by the formula (I) is preferably saturated and may be linear, branched or cyclic. Specific examples thereof include those in which some or all of the hydrogen atoms of the hydrocarbyl groups have been substituted with fluorine atoms. Specific examples thereof include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoro-1-propyl group, a 3,3,3-trifluoro-2-propyl group, a 2,2,3,3-tetrafluoropropyl group, a 1,1,1,3,3,3-hexafluoroisopropyl group, a 2,2,3,3,4,4,4-heptafluorobutyl group, a 2,2,3,3,4,4,5,5-octafluoropentyl group, a 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl group, a 2-(perfluorobutyl)ethyl group, a 2-(perfluorohexyl)ethyl group, a 2-(perfluorooctyl)ethyl group, and a 2-(perfluorodecyl)ethyl group.

[0283] Examples of the repeating units represented by formulae (6A) to (6E) include, but are not limited to, those shown below. In the following formulae, R B is the same as above. [ka]

[0284] [ka]

[0285] [ka]

[0286] [ka]

[0287] [ka]

[0288] The polymer surfactant may further contain other repeating units than the repeating units represented by formulae (6A) to (6E). Examples of the other repeating units include repeating units obtained from methacrylic acid and α-trifluoromethylacrylic acid derivatives. In the polymer surfactant, the content of the repeating units represented by formulae (6A) to (6E) in the total repeating units is preferably 20 mol % or more, more preferably 60 mol % or more, and even more preferably 100 mol %.

[0289] The Mw of the polymer surfactant 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 2.0, and more preferably from 1.0 to 1.6.

[0290] The method for synthesizing the polymeric surfactant includes a method in which a monomer containing an unsaturated bond that gives the repeating units represented by formulae (6A) to (6E) and other repeating units as necessary is heated in an organic solvent with the addition of a radical initiator to polymerize. Examples of the organic solvent used during polymerization include toluene, benzene, THF, diethyl ether, and dioxane. Examples of the polymerization initiator 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 it is, or may be protected or partially protected after polymerization.

[0291] When synthesizing the polymeric surfactant, 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 moles of the monomers to be polymerized.

[0292] When a surfactant (K) is contained, its content is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the base polymer (P). When the added amount is 0.1 part by mass or more, the receding contact angle between the resist film surface and water is sufficiently improved, and when it is 50 parts by mass or less, the dissolution rate of the resist film surface in the developer is low, and the height of the formed fine pattern is sufficiently maintained.

[0293] [(L) Other ingredients] The chemically amplified resist composition of the present invention may contain, as other components (L), a compound that decomposes with an acid to generate an acid (acid amplifying compound), an organic acid derivative, a fluorine-substituted alcohol, a compound with Mw of 3,000 or less that changes in solubility in a developer by the action of an acid (dissolution inhibitor), and the like. As the acid amplifying compound, the compounds described in JP-A-2009-269953 or JP-A-2010-215608 can be referred to. When the acid amplifying compound is contained, the content is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass, relative to 80 parts by mass of the base polymer (P). Within the above range, diffusion is easily controlled, and degradation of resolution and pattern shape does not occur. As the organic acid derivative, fluorine-substituted alcohol, and dissolution inhibitor, the compounds described in JP-A-2009-269953 or JP-A-2010-215608 can be referred to.

[0294] [Pattern formation method] The pattern forming method of the present invention comprises the steps of: (i) forming a resist film on a substrate using a resist composition containing the polymer; (ii) exposing the resist film to high energy radiation; (iii) developing the exposed resist film with a developer.

[0295] In the above step (i), the substrate may be, for example, a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.).

[0296] In the above step (i), the resist film can be formed, for example, by applying the resist composition by a method such as spin coating to a film thickness of 0.05 to 2 μm, and then pre-baking this on a hot plate, preferably at 60 to 150° C. for 1 to 10 minutes, more preferably at 80 to 140° C. for 1 to 5 minutes.

[0297] In the above step (ii), examples of high energy rays used for exposing the resist film include i-rays, KrF excimer laser light, ArF excimer laser light, electron beams (EB), extreme ultraviolet light (EUV), etc., and extreme ultraviolet light having a wavelength of 3 to 15 nm may be used. When KrF excimer laser light, ArF excimer laser light, or EUV is used for exposure, a mask for forming a desired pattern is used, and the exposure dose is preferably 1 to 200 mJ / cm. 2 , more preferably 10 to 100 mJ / cm 2 When EB is used, the exposure is preferably performed by irradiating the film with an exposure dose of 1 to 300 μC / cm 2 using a mask for forming a desired pattern or directly. 2 , more preferably 10 to 200 μC / cm 2 The exposure can be performed by irradiating the light so as to satisfy the above condition.

[0298] In addition to the usual exposure method, the immersion method can be used in which a liquid with a refractive index of 1.0 or more is placed between the resist film and the projection lens. In this case, a water-insoluble protective film can also be used.

[0299] The water-insoluble protective film is used to prevent elution from the resist film and to increase the water sliding property of the film surface, and is roughly divided into two types. One is an organic solvent stripping type that needs to be stripped before alkaline aqueous solution development by an organic solvent that does not dissolve the resist film, and the other is an alkaline aqueous solution soluble type that is soluble in an alkaline developer and removes the protective film together with removing the soluble part of the resist film. The latter is based on a polymer having a 1,1,1,3,3,3-hexafluoro-2-propanol residue that is insoluble in water and soluble in an alkaline developer, and is preferably a material dissolved in an alcohol-based solvent having 4 or more carbon atoms, an ether-based solvent having 8 to 12 carbon atoms, or a mixed solvent thereof. The above-mentioned water-insoluble and alkaline developer-soluble surfactant can also be dissolved in an alcohol-based solvent having 4 or more carbon atoms, an ether-based solvent having 8 to 12 carbon atoms, or a mixed solvent thereof.

[0300] After the exposure, PEB may be performed, for example, by heating on a hot plate at preferably 60 to 150° C. for 1 to 5 minutes, more preferably 80 to 140° C. for 1 to 3 minutes.

[0301] In the above step (iii), a positive tone development method can be used in which an alkaline aqueous solution is used as a developer to dissolve the exposed areas while leaving the unexposed areas undissolved. This method can provide a positive tone pattern.

[0302] In the above step (iii), the developer may be, for example, an alkaline aqueous solution of tetramethylammonium hydroxide (TMAH) or the like, preferably 0.1 to 5% by mass, more preferably 2 to 3% by mass. In addition, the development is carried out for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, by a conventional method such as a dip method, a puddle method, or a spray method, to form a desired pattern on the substrate.

[0303] As a means for forming a pattern, after forming a resist film, a pure water rinse (post soak) may be performed to extract an acid generator and the like from the film surface or to wash away particles, or a rinse (post soak) may be performed to remove water remaining on the film after exposure.

[0304] Furthermore, the pattern may be formed by a double patterning method. Examples of the double patterning method include a trench method in which a 1:3 trench pattern is processed by a first exposure and etching, and a 1:3 trench pattern is formed by a second exposure with a shifted position to form a 1:1 pattern, and a line method in which a first base with a 1:3 isolated leave pattern is processed by a first exposure and etching, and a second base with a 1:3 isolated leave pattern formed under the first base is processed by a second exposure with a shifted position to form a 1:1 pattern with half the pitch.

[0305] In the pattern forming method of the present invention, a negative tone development method may be used in which an organic solvent is used as a developer instead of the alkaline aqueous solution in the step (iii) to dissolve and develop the unexposed areas. By this method, a negative pattern can be obtained.

[0306] The organic solvent development may be carried out using the following developing solutions: 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, propyl cyclohexanone ... Examples of the organic solvent that can be used 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. EXAMPLES

[0307] The present invention will be specifically described below with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples. The apparatuses used are as follows. IR: Thermo Fisher Scientific, NICOLET 6700 · 1 H-NMR: ECA-500 manufactured by JEOL Ltd. · 19 F-NMR: ECA-500 manufactured by JEOL Ltd.

[0308] [1] Synthesis of monomer [Synthesis of Monomer A1] [ka]

[0309] (1) Synthesis of intermediate 1 Under a nitrogen atmosphere, a solution consisting of raw material 1 (136.1 g) and THF (150 ml) was dropped into a solution obtained by diluting methyl magnesium chloride (800 ml 3.0 M THF solution) with THF (800 ml) while maintaining the internal temperature at 45 ° C or less. After stirring for 2 hours at an internal temperature of 50 ° C, the reaction solution was ice-cooled, and a mixed aqueous solution of ammonium chloride (240 g) and 3.0 mass % hydrochloric acid aqueous solution (1200 g) was dropped to stop the reaction. Ethyl acetate (1000 mL) was added, and a normal aqueous work-up was performed. After distilling off the solvent, the solution was recrystallized with hexane to obtain 146.1 g of intermediate 1 as white crystals (yield 96%).

[0310] (2) Synthesis of intermediate 2 Under a nitrogen atmosphere, methacrylic acid chloride (240.8 g) was added dropwise to a solution of intermediate 1 (146.1 g), triethylamine (272 g), dimethylaminopyridine (11.7 g) and acetonitrile (450 mL) in an ice bath. After the addition, the internal temperature was raised to 50°C and aged for 20 hours. The reaction solution was ice-cooled and saturated sodium bicarbonate water (300 mL) was added dropwise to stop the reaction. The mixture was extracted with toluene (500 mL), subjected to a normal aqueous work-up, and the solvent was distilled off, followed by purification by silica gel column chromatography to obtain 257.4 g of intermediate 2 as a colorless oil (yield 93%).

[0311] (3) Synthesis of Monomer A1 Under a nitrogen atmosphere, intermediate 2 (257.4 g) was dissolved in THF (400 ml), and 25% by mass aqueous sodium hydroxide solution (171.4 g) was added dropwise in an ice bath. After the addition, the internal temperature was raised to 25°C and aged for 15 hours. The reaction solution was ice-cooled, and 20% by mass aqueous hydrochloric acid solution (244.1 g) was added dropwise to stop the reaction. The mixture was extracted with toluene (500 mL), subjected to a normal aqueous work-up, and the solvent was distilled off, followed by purification by silica gel column chromatography to obtain 177 g of monomer A1 as a colorless oil (yield 90%).

[0312] IR spectrum data of monomer A1 and 1 The H-NMR results are shown below. IR(D-ATR): ν= 3392, 2982, 2930, 1717, 1698, 1634, 1620, 1590, 1490, 1451, 1402,1382, 1367, 1329, 1313, 1292, 1196, 1135, 1105, 1078, 1009, 941, 896, 867, 815, 784, 701, 652, 575, 475 cm -1 . 1 H-NMR(600MHz in DMSO-d6): δ= 9.34(1H, s), 7.10(1H, t), 6.74(2H, m), 6.62(1H, d), 6.02(1H, d), 5.64(1H, d), 1.85(3H, s), 1.69(6H, s) ppm.

[0313] [Synthesis of Monomer A2] Monomer A2 was obtained as a colorless, transparent oil (total yield 82%) by carrying out synthesis in the same manner as in (1) to (3) of Synthesis Example 1-1, except that Raw Material 2 was used instead of Raw Material 1. [ka]

[0314] IR spectrum data of monomer A2 and 1 H-NMR, 19 The F-NMR results are shown below. IR(D-ATR): ν= 3402, 2988, 2927, 1705, 1635, 1608, 1507, 1470, 1450, 1437, 1403,1384, 1379, 1369, 1340, 1327, 1313, 1277, 1213, 1190, 1136, 1119, 1087, 1013, 970, 949, 920, 866, 835, 812, 772, 715, 661, 551 cm -1 . 1H-NMR(600MHz in DMSO-d6): δ= 9.78(1H, s), 7.05(1H, dd), 6.93(1H, dd), 6.74(1H, m), 6.02(1H, d), 5.65(1H, d), 1.85(3H, s), 1.68(6H, s) ppm. 19 F-NMR (600MHz in DMSO-d6): δ= -140.41(1F, m) ppm.

[0315] [Synthesis of Monomers A3 to A10] Monomers A3 to A10 were synthesized using raw materials corresponding to the monomers A3 to A10. [ka]

[0316] [Synthesis of Comparative Monomers AX1 to AX8] Comparative example monomers AX1 to AX8 were synthesized as comparative example monomers of unit A using raw materials corresponding to the monomers AX1 to AX8. [ka]

[0317] [2] Polymer synthesis Among the monomers used in the synthesis of the polymer, the following monomers were used as monomers other than the monomers A1 to A10 and the comparative monomers AX1 to AX8.

[0318] Monomers A1 and A2 [ka]

[0319] Monomer B [ka]

[0320] Monomer C [ka]

[0321] Monomer D [ka]

[0322] [Synthesis of polymer P-1] In a nitrogen atmosphere, monomer A1 (50.1 g), monomer a1-1 (22.3 g), monomer B1 (48.7 g), 3.80 g of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator, and 225 g of MEK were placed in a flask to prepare a monomer-polymerization initiator solution. 75 g of MEK was placed in another flask in a nitrogen atmosphere, and the mixture was heated to 80° C. with stirring, and the monomer-polymerization initiator solution was then dropped over 4 hours. After the dropwise addition, the temperature of the polymerization liquid was kept at 80° C. and the mixture was stirred for 2 hours, and then cooled to room temperature. The obtained polymerization liquid was dropped into 2,000 g of vigorously stirred hexane, and the precipitated polymer was filtered off. Furthermore, the obtained polymer was washed twice with 600 g of hexane, and then vacuum dried at 50° C. for 20 hours to obtain a white powdery polymer P-1 (yield 98.1 g, yield 98%). Polymer P-1 had an Mw of 10,000 and an Mw / Mn ratio of 2.03. Note that Mw was a value measured in terms of polystyrene by GPC using DMF as a solvent.

[0323] [ka]

[0324] [Synthesis of polymers P-2 to P-20 and comparative polymers CP-1 to CP-20] Polymers shown in Tables 1 and 2 were produced in the same manner as for polymer P-1, except that the types and compounding ratios of each monomer were changed.

[0325] [Table 1]

[0326] [Table 2]

[0327] [3] Preparation of resist composition [Examples 1-1 to 1-20, Comparative Examples 1-1 to 1-20] The polymers of the present invention (P-1 to P-20), the comparative polymers (CP-1 to CP-20), the photoacid generators (PAG-1, PAG-2), the quenchers (SQ-1 to SQ-3, AQ-1) were dissolved in solutions of 100 ppm of FC-4430 (manufactured by 3M) in the compositions shown in Tables 3 and 4 below, and the solutions were filtered through a 0.2 μm Teflon (registered trademark) filter to prepare resist compositions.

[0328] In Tables 3 and 4, the components are as follows. Organic solvent 1: PGMEA (propylene glycol monomethyl ether acetate) Organic solvent 2: DAA (diacetone alcohol)

[0329] Photoacid generator: PAG-1, PAG-2 [ka]

[0330] Quencher: SQ-1~SQ-3, AQ-1 [ka]

[0331] [Table 3]

[0332] [Table 4]

[0333] [4] EUV Lithography Evaluation (1) [Examples 2-1 to 2-20, Comparative Examples 2-1 to 2-20] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-20) in Tables 3 and 4 was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. had been formed to a thickness of 20 nm, and the substrate was pre-baked at 100°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. This was exposed to an LS pattern with an on-wafer dimension of 18 nm and a pitch of 36 nm using an ASML EUV scanner NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination) by varying the exposure dose and focus of extreme ultraviolet light with a wavelength of 13.5 nm (exposure dose pitch: 1 mJ / cm 2 After exposure, PEB was performed for 60 seconds at the temperatures shown in Tables 5 and 6. Paddle development was then performed for 30 seconds with a 2.38% by mass TMAH aqueous solution, followed by rinsing with a surfactant-containing rinse material and spin drying to obtain a positive pattern. The developed LS pattern was observed with a critical dimension SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, and the sensitivity, EL, LWR, and DOF were evaluated according to the following methods. The results are shown in Tables 5 and 6.

[0334] [Sensitivity evaluation] The optimal exposure dose E for obtaining an LS pattern with a line width of 18 nm and a pitch of 36 nm op (mJ / cm 2 ) was calculated and used as the sensitivity.

[0335] [EL Rating] From the exposure amount formed within the range of ±10% (16.2 to 19.8 nm) of the 18 nm space width in the LS pattern, EL (unit: %) was calculated by the following formula. The larger this value, the better the performance. EL(%)=(|E1-E2| / E op ) x 100 E1: Optimal exposure dose for LS pattern with line width of 16.2 nm and pitch of 36 nm E2: Optimal exposure dose for LS pattern with line width of 19.8 nm and pitch of 36 nm E op : Optimal exposure dose to give LS pattern with line width of 18 nm and pitch of 36 nm

[0336] [LWR rating] E op The dimensions of the LS pattern obtained by irradiating with 10000 times the light were measured in the longitudinal direction of the lines, 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 of the pattern obtained.

[0337] [DOF evaluation] For the evaluation of the depth of focus, the focus range formed within the range of ±10% (16.2 to 19.8 nm) of the dimension of 18 nm in the LS pattern was obtained. The larger this value, the wider the depth of focus and the wider the process margin of the resist pattern.

[0338] [Table 5]

[0339] [Table 6]

[0340] From the results shown in Tables 5 and 6, it can be seen that the resist compositions of the Examples generally had larger EL values ​​and DOF values, and tended to have smaller optimum exposure doses and LWR values ​​than the comparative examples. Therefore, it was confirmed that the resist compositions using the polymers of the present invention had good sensitivity and performance, formed patterns with small roughness, and had wide depth of focus, and were therefore excellent in various lithography performances.

[0341] [5] EUV Lithography Evaluation (2) [Examples 3-1 to 3-20, Comparative Examples 3-1 to 3-20] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-20) shown in Tables 3 and 4 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) made by Shin-Etsu Chemical Co., Ltd. was formed to a thickness of 20 nm, and the resist film was pre-baked for 60 seconds at 105°C using a hot plate to prepare a resist film with a thickness of 50 nm. This was exposed to extreme ultraviolet light with a wavelength of 13.5 nm using an EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, wafer dimensions with a pitch of 46 nm, and a hole pattern mask with a +20% bias), and PEB was performed for 60 seconds using a hot plate at the temperatures shown in Tables 7 and 8, and development was performed for 30 seconds with a 2.38% by mass TMAH aqueous solution to form a hole pattern with a dimension of 23 nm.

[0342] Using a Hitachi High-Technologies Corporation CD-SEM (CG6300), the exposure dose when the hole dimension was 23 nm was measured and used as the sensitivity (optimum exposure dose). The dimensions of 50 holes were also measured, and the standard deviation (σ) calculated from the results was tripled (3σ) to give the dimensional variation (CDU). The results are shown in Tables 7 and 8.

[0343] [Table 7]

[0344] [Table 8]

[0345] From the results shown in Tables 7 and 8, the resist compositions of the examples tended to have lower optimum exposure doses and CDU values ​​overall compared to the comparative examples, which confirmed that the resist compositions using the polymers of the present invention have good sensitivity and excellent in-plane pattern uniformity.

[0346] As described above, it has been demonstrated that the present invention provides a polymer, a resist material, and a pattern formation method that are capable of forming a resist pattern with high sensitivity, high resolution, and high contrast, as well as small line width variation (LWR) and pattern within wafer uniformity (CDU), and a wide process margin, in lithography, an ultrafine processing technology that uses high-energy rays.

[0347] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

1. A polymer which generates an acid upon exposure to light and changes its solubility in a developer by the action of the acid, A polymer comprising a repeating unit represented by the following formula (A-1) and one or more repeating units represented by the following formulas (B-1) to (B-4): 【Chemistry 1】 (In the formula, R Ａ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Ａ is a single bond, (main chain) -C(=O)-O-Z Ａ１ -, or an alkoxy group having 1 to 10 carbon atoms which may contain a fluorine atom, or a phenylene group or naphthylene group which may contain a halogen atom; Z Ａ１ R is an alkoxy group having 1 to 10 carbon atoms which may contain a heteroatom or a fluorine atom, a hydroxyl group, a linear, branched or cyclic alkanediyl group having 1 to 20 carbon atoms which may contain an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. Ｂ and R Ｃ are each independently a linear, branched or cyclic hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom; R Ｂ and R Ｃ may be bonded to each other to form a ring structure. １ａ R each independently represents a halogen atom, a cyano group, an acyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine-containing alkyl group having 1 to 5 carbon atoms, or a fluorine-containing alkoxy group having 1 to 5 carbon atoms. １ｂ are each independently a linear, branched or cyclic 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 2, n3 is an integer of 0 to 5, and n4 is an integer of 0 to 2. Z １ is a single bond or a phenylene group. Z ２ is a single bond, -C(=O)-O-Z ２１ -, -C(=O)-NH-Z ２１ -or-O-Z ２１ - is. 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 hydroxyl group. Z ３ represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-O-Z ３１ - is. 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, a methylene group, or -Z ４１ -C(=O)-O-. Z ４１ is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom, an ether bond, or an ester bond. 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)-NH-Z ５１ -or-O-Z ５１ - is. ５１ represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. R ２１ and R ２２ R is each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. ２１ and R ２２ may be bonded to each other to form a ring together with the sulfur atom to which they are attached. L １１ 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. M － is a non-nucleophilic counterion. A ＋ is an onium cation. c is an integer from 0 to 3.

2. The polymer according to claim 1, wherein the repeating unit represented by formula (A-1) is a repeating unit represented by the following formula (A-2): 【Chemistry 2】 (In the formula, R Ａ , Z Ａ , R Ｂ , R Ｃ , R １ａ , R １ｂ , n1, n2, and n3 are the same as above.)

3. R in the above formula (A-1) １ａ The polymer according to claim 1 or 2, characterized in that: is any one of a fluorine atom, a trifluoromethyl group, and a trifluoromethoxy group.

4. A in the formulas (B-2) to (B-4) ＋ The polymer according to any one of claims 1 to 3, characterized in that: 【Chemistry 3】 (In the formula, R １１ , R １２ and R １３ each independently represents a linear, branched or cyclic monovalent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom. １１ , R １２ and R １３ Any two of R may be bonded to each other to form a ring together with the sulfur atom in the formula. １４ and R １５ are each independently a linear, branched or cyclic monovalent hydrocarbon group having 1 to 30 carbon atoms which may contain a heteroatom.

5. The polymer according to any one of claims 1 to 4, further comprising a repeating unit represented by the following formula (a-1) or (a-2): 【Chemistry 4】 (In the formula, R Ａ , Z Ａ is the same as above. Ｂ R is a single bond, (main chain) -C(=O)-O-, or an alkanediyl group having 1 to 10 carbon atoms which may contain an ester group, an ether group, or a carbonyl group. ｂ is a linear, branched or cyclic hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a halogen atom, an alkoxy group which may contain fluorine, or a cyano group. p is an integer of 0 to 4. Ａ and X Ｂ each independently represents an acid labile group not containing a fluorine-containing aromatic ring.

6. The polymer according to any one of claims 1 to 5, further comprising a repeating unit represented by the following formula (C-1): 【Chemistry 5】 (In the formula, R Ａ is the same as above. Ｂ R is a single bond or (main chain) -C(=O)-O-, or an alkanediyl group having 1 to 10 carbon atoms which may contain an ester group, an ether group, or a carbonyl group. ｂ１ 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. m is an integer of 1 to 4, k is an integer of 0 to 3, and m+k is an integer of 4 or less.

7. The polymer according to any one of claims 1 to 6, further comprising a repeating unit represented by the following formula (D-1): 【Chemistry 6】 (In the formula, R Ａ , Z Ａ , is the same as above. Y Ａ is a hydrogen atom, or a polar group containing at least one structure selected from a hydroxy group, a cyano group, a carbonyl group, a carboxy group, an ether bond, an ester bond, a sulfonate ester bond, a sulfonamide bond, a carbonate bond, a lactone ring, a sultone ring, a sulfur atom, and a carboxylic acid anhydride.

8. A resist composition comprising the polymer according to claim 1 .

9. The resist composition according to claim 8, further comprising an organic solvent.

10. 10. The resist composition according to claim 8, further comprising a photoacid generator other than the photoacid generator bonded to the polymer chain.

11. 11. The resist composition according to claim 8, further comprising a quencher.

12. 12. The resist composition according to claim 8, further comprising a surfactant that is insoluble or poorly soluble in water and soluble in an alkaline developer, and / or a surfactant that is insoluble or poorly soluble in water and an alkaline developer.

13. A pattern formation method comprising the steps of: (i) forming a resist film on a substrate using the resist composition according to any one of claims 8 to 12; (ii) exposing the resist film to high energy radiation; (iii) developing the exposed resist film with a developer; A pattern forming method comprising the steps of:

14. 14. The pattern formation method according to claim 13, wherein the high energy beam in the step (ii) is i-beam, KrF excimer laser beam, ArF excimer laser beam, electron beam or extreme ultraviolet ray having a wavelength of 3 to 15 nm.

15. 15. The method for forming a pattern according to claim 13, wherein the developer in the step (iii) is an aqueous alkaline solution, which dissolves exposed areas and does not dissolve unexposed areas to obtain a positive pattern.

16. 15. The method for forming a pattern according to claim 13, wherein the developer in the step (iii) is an organic solvent, which dissolves unexposed areas and provides a negative pattern in which exposed areas are insoluble.

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