Polymer, resist composition, and pattern forming method

Abstract

To provide a polymer included in a resist composition, offering high sensitivity, high resolution, and high contrast, particularly in electron beams and extreme ultraviolet rays (EUV) at a wavelength of 13.5 nm, enabling patterning with small LWR and CDU, and ensuring superior etching resistance, to provide a resist composition including the polymer, and a patterning method using the same.SOLUTION: A polymer (P) generates acid upon exposure to light, and shows a change in solubility in developer under the action of acid, comprising a repeat unit represented by the formula (A-1), a repeat unit that generates acid upon exposure to light, and a repeat unit other than the one represented by the formula (A-1).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 density of integrated circuits has led to the demand for finer pattern formation, and chemically amplified resists using acid as a catalyst are now used exclusively for processing patterns of 0.2 μm or less. High-energy beams such as ultraviolet, far ultraviolet, 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 method for processing photomask blanks when producing photomasks for semiconductor manufacturing.

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

[0004] The base polymers used in positive-tone EB lithography resist compositions and EUV lithography resist compositions are typically materials that, upon exposure to high-energy radiation, use an acid generated from a photoacid generator as a catalyst to deprotect the acid-labile protecting groups masking the acidic functional groups on the phenol side chains of the base polymer, rendering the polymer soluble in alkaline developers. Furthermore, tertiary alkyl groups, tert-butoxycarbonyl groups, acetal groups, and the like have typically been used as the acid-labile protecting groups. While using a protecting group such as an acetal group, which requires a relatively low activation energy for deprotection, offers the advantage of producing highly sensitive resist films, insufficient suppression of the diffusion of the generated acid can lead to deprotection reactions even in unexposed areas of the resist film, resulting in problems such as poor line edge roughness (LER) and reduced pattern uniformity (CDU).

[0005] As miniaturization progresses, image blurring due to acid diffusion has become a problem. It has been proposed that controlling acid diffusion is important to ensure resolution in fine patterns, in addition to improving dissolution contrast, as previously proposed. However, because chemically amplified resist materials increase sensitivity and contrast through acid diffusion, attempts to minimize acid diffusion by shortening the post-exposure bake (PEB) temperature and time result in a significant decrease in sensitivity and contrast. The type of acid-labile group is closely related to the acid diffusion distance, and there is a need to develop acid-labile groups that allow deprotection reactions to proceed over extremely short acid diffusion distances.

[0006] It has been pointed out that ArF resists in which the carboxyl group of methacrylic acid or the like is substituted with an acid labile group swell in alkaline developers. On the other hand, KrF resists in which the phenol group of hydroxystyrene or the like is substituted with an acid labile group swell less. However, hydroxystyrene has a high acid diffusion rate, which raises concerns about reduced resolution. Structural units in which the carboxyl group of styrene carboxylic acid is substituted with an acid labile group have also been proposed (Patent Documents 1 to 3). However, there is still room for improvement, and the development of resists with low acid diffusion and minimal swelling in alkaline developers is desired.

[0007] Various improvements have been made to control resist sensitivity and pattern profile by selecting and combining materials used in resist compositions, process conditions, etc. One of these improvements addresses the issue of acid diffusion, which has a significant impact on the resolution of chemically amplified resist compositions. This issue of acid diffusion has been the subject of extensive research because of its significant impact on sensitivity and resolution.

[0008] In order to suppress the diffusion of acid, polymers in which a photoacid generator is copolymerized into the structural units of a base polymer have been investigated. In particular, anion-bound polymers in which the anion moiety of an ionic photoacid generator is copolymerized into the main chain of a base polymer are effective in suppressing the diffusion of generated acid, and many studies have been conducted on them (Patent Documents 4 to 6).

[0009] Along with the formation of fine patterns, the etching resistance of the resist pattern is also important. The indene copolymer disclosed in Patent Document 7 and the acenaphthylene copolymer disclosed in Patent Document 8 are expected to have improved etching resistance not only due to their high carbon density but also due to the rigid main chain structure of the cycloolefin structure. In order to meet the demand for further miniaturization, there is a need for the development of resist materials that have controlled acid diffusion, excellent lithography performance, and excellent etching resistance of the resist pattern. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent No. 6237763 [Patent Document 2] Patent No. 6694451 [Patent Document 3] Patent No. 7055070 [Patent Document 4] Patent No. 5954253 [Patent Document 5] Patent No. 6702264 [Patent Document 6] Japanese Patent Application Publication No. 2018-013687 [Patent Document 7] Patent No. 3865048 [Patent Document 8] Japanese Patent Application Laid-Open No. 2006-169302 Summary of the Invention [Problem to be solved by the invention]

[0011] There is a need for the development of acid-catalyzed chemically amplified resist compositions that achieve even higher sensitivity and resolution in fine pattern formation, improve LWR in line patterns and CDU in hole patterns, and have excellent etching resistance.

[0012] The present invention has been made in view of the above circumstances, and aims to provide a polymer contained in a resist composition that enables the formation of patterns with high sensitivity, high resolution, and high contrast, as well as small LWR and CDU, when exposed to high-energy rays, particularly electron beams and extreme ultraviolet rays (EUV) with a wavelength of 13.5 nm, and that also has excellent etching resistance; a resist composition containing the polymer; and a pattern formation method using the same. [Means for solving the problem]

[0013] In order to solve the above-mentioned problems, the present invention provides a polymer (P) that generates an acid upon exposure and whose solubility in a developer is changed by the action of the acid, the polymer comprising a repeating unit represented by the following formula (A-1); a repeating unit that generates an acid upon exposure and is represented by one or more selected from the following formulas (B-1), (B-2), (B-3), and (B-4): [ka] (In formula (A-1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. L1 , R L2 , and R L3 are each independently a hydrocarbyl group having 1 to 30 carbon atoms, and R L1 , R L2 , and R L3 Any two of R may be bonded to each other to form a ring. L1 , R L2 , and R L3 When L do not bond to each other to form a ring, at least one of them has a multiple bond, an alicyclic ring, or an aromatic ring structure. A is a single bond, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond. L R is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. 1 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. n1 is an integer of 0 or 1. n2 is an integer of 1 or 2. n3 is an integer of 0 to 6, but when n1=0, 1≦n2+n3≦5, and when n1=1, 1≦n2+n3≦7. 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 -C(=O)-OZ 21 -, -C(=O)-NH-Z 21-or- OZ 21 -It is. Z 21 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 3 represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-OZ 31 -It is. Z 31 Z is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. 4 is a single bond or -Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -C(=O)-OZ 51 -, -C(=O)-NH-Z 51 -or- OZ 51 -It is. Z 51 R is 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. 21 and R 22 R are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 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. 1 and Rf 2 Rf are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. - is a non-nucleophilic counterion. + is an onium cation, and c is an integer of 0 to 3. [ka] (In the formula, R A is the same as above. Z A represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-OZ A1 - and Z A1 Z is a linear, branched or cyclic alkanediyl group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. B is a single bond or (main chain) -C(=O)-O-. b is a linear, branched or cyclic hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. p is an integer of 0 to 4. X A and X B are each independently an acid labile group.

[0014] Such a polymer will enable the formation of patterns with high sensitivity, high resolution, and high contrast, as well as small LWR and CDU, when used with high-energy beams, particularly electron beams and extreme ultraviolet rays (EUV) with a wavelength of 13.5 nm, and will also be a polymer to be contained in a resist composition that has excellent etching resistance.

[0015] In the present invention, 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 , R L1 , R L2 , R L3 , R 1 , L A , X L, n2, and n3 are the same as above.)

[0016] In the present invention, it is preferable to use such a repeating unit.

[0017] In this case, the repeating unit represented by the formula (A-2) is preferably a repeating unit represented by the following formula (A-3). [ka] (In the formula, R A , R L1 , R L2 , R L3 , R 1 , n2, and n3 are the same as above.)

[0018] In the present invention, it is more preferable to use such a repeating unit.

[0019] In the present invention, the repeating units (B-2), (B-3), and (B-4) that generate an acid upon exposure are each selected from the group consisting of A + The onium cation preferably contains an onium 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 hydrocarbyl 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 each independently represents a linear, branched or cyclic hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom.

[0020] In the present invention, it is preferable to use such an onium cation.

[0021] In the present invention, it is preferable that the polymer (P) further contains a repeating unit represented by the following formula (C-1). [ka] (In the formula, R A , Z B is the same as above. R b1 represents a halogen atom, a cyano group, or a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, which may contain a heteroatom. m represents an integer of 1 to 4, k represents an integer of 0 to 3, and m+k represents an integer of 1 to 4.

[0022] The present invention preferably has such a repeating unit.

[0023] In the present invention, it is preferable that the polymer (P) 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 carbonate bond, a lactone ring, a sultone ring, and a carboxylic acid anhydride.

[0024] The present invention more preferably has such a repeating unit.

[0025] The present invention also provides a resist composition containing the above-described polymer.

[0026] Such a resist composition enables the formation of patterns with high sensitivity, high resolution, and high contrast, as well as small LWR and CDU, when exposed to high-energy rays, particularly electron beams and extreme ultraviolet rays (EUV) with a wavelength of 13.5 nm, and also provides excellent etching resistance.

[0027] In this case, it is preferable that the solvent further contains an organic solvent.

[0028] Such a resist composition is preferable because it is easy to handle.

[0029] In this case, it is preferable that the polymer (P) further contains a photoacid generator other than the structural unit that generates an acid upon exposure to light.

[0030] Such a resist composition is preferable because it provides good resolution and there is no risk of problems with foreign matter occurring after development or during stripping of the resist film.

[0031] In this case, it is preferable that the compound further contains a quencher.

[0032] Such a resist composition is preferable because it has good resolution and does not cause a significant decrease in sensitivity.

[0033] In this case, it is preferable that the composition further contains a surfactant that is insoluble or slightly soluble in water but soluble in an alkaline developer, and / or a surfactant that is insoluble or slightly soluble in water and an alkaline developer.

[0034] Such a resist composition is preferred because it satisfactorily improves the receding contact angle between the resist film surface and water, reduces the dissolution rate of the resist film surface in a developer, and ensures that the height of the formed fine pattern is adequately maintained.

[0035] The present invention also provides a pattern forming method including the steps of forming a resist film on a substrate using the resist composition described above, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer.

[0036] This pattern formation method makes it possible to form patterns with high sensitivity, high resolution, and high contrast, as well as small LWR and CDU, using high-energy beams, particularly electron beams and extreme ultraviolet rays (EUV) with a wavelength of 13.5 nm.

[0037] In this case, it is preferable to use i-rays, KrF excimer laser light, ArF excimer laser light, electron beams, or extreme ultraviolet rays with a wavelength of 3 to 15 nm as the high energy rays.

[0038] Such a pattern forming method allows for good pattern formation.

[0039] In this case, it is preferable to use an alkaline aqueous solution as the developer to dissolve the exposed areas and to obtain a positive pattern in which the unexposed areas do not dissolve.

[0040] Such a pattern forming method can provide a positive pattern.

[0041] In this case, it is preferable to use an organic solvent as the developer to dissolve the unexposed areas and obtain a negative pattern in which the exposed areas do not dissolve.

[0042] Such a pattern forming method can provide a negative pattern. [Effects of the Invention]

[0043] As described above, by using the polymer of the present invention and a resist composition containing the polymer, it is possible to construct a resist pattern that has high sensitivity, small LWR and CDU, high contrast, excellent resolution, and a wide process margin, and it is also possible to form a pattern that has excellent etching resistance. DETAILED DESCRIPTION OF THE INVENTION

[0044] As mentioned above, there was a need for the development of a polymer contained in a resist composition that would enable the formation of patterns with high sensitivity, high resolution, and high contrast, as well as small LWR and CDU, and that would also have excellent etching resistance, particularly for electron beams and extreme ultraviolet (EUV) rays with a wavelength of 13.5 nm.

[0045] As a result of extensive research into achieving the above-mentioned object, the present inventors have found that by using a resist composition containing a polymer including a repeating unit having an acid labile group, in which the polymerizable group is a vinyl aromatic unit, and a repeating unit that generates an acid upon specific exposure, it is possible to form a pattern with high sensitivity, high contrast, excellent resolution, and a wide process margin that is excellent in terms of LWR of a line pattern and CDU of a hole pattern.In addition, since the resist composition also has excellent etching resistance, it is extremely effective for forming fine patterns, and has completed the present invention.

[0046] That is, the present invention provides a polymer (P) that generates an acid upon exposure and whose solubility in a developer is changed by the action of the acid, the polymer comprising a repeating unit represented by the following formula (A-1); a repeating unit that generates an acid upon exposure and is represented by any one or more selected from the following formulas (B-1), (B-2), (B-3), and (B-4); and a repeating unit represented by the following formula (a-1) or (a-2) other than the repeating unit represented by formula (A-1). [ka] (In formula (A-1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. L1 , R L2 , and R L3 are each independently a hydrocarbyl group having 1 to 10 carbon atoms, and R L1 , R L2 , and R L3 Any two of R may be bonded to each other to form a ring.L1 , R L2 , and R L3 When L do not bond to each other to form a ring, at least one of them has a multiple bond, an alicyclic ring, or an aromatic ring structure. A is a single bond, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond. L R is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. 1 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. n1 is an integer of 0 or 1. n2 is an integer of 1 or 2. n3 is an integer of 0 to 6, but when n1=0, 1≦n2+n3≦5, and when n1=1, 1≦n2+n3≦7. 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 -C(=O)-OZ 21 -, -C(=O)-NH-Z 21 -or- OZ 21 -It is. Z 21 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 3 represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-OZ 31 -It is. Z 31 Z is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. 4 is a single bond or -Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -C(=O)-OZ 51 -, -C(=O)-NH-Z51 -or- OZ 51 -It is. Z 51 R is 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. 21 and R 22 R are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 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. 1 and Rf 2 Rf are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. - is a non-nucleophilic counterion. + is an onium cation, and c is an integer of 0 to 3. [ka] (In the formula, R A is the same as above. Z A represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-OZ A1 - and Z A1 Z is a linear, branched or cyclic alkanediyl group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. B is a single bond or (main chain) -C(=O)-O-. b is a linear, branched or cyclic hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. p is an integer of 0 to 4. X A and X Bare each independently an acid labile group.

[0047] The present invention will be described in detail below, but the present invention is not limited thereto.

[0048] Polymer The polymer (P) of the present invention contains specific repeating units other than repeating units having an acid labile group that contains a vinyl aromatic unit in the polymerizable group, repeating units that generate acid upon exposure, and repeating units having an acid labile group that contains a vinyl aromatic unit in the polymerizable group.

[0049] [Repeating unit having an acid labile group containing a vinyl aromatic unit in the polymerizable group (repeating unit A)] The polymer (P) of the present invention contains a repeating unit having an acid labile group containing a vinyl aromatic unit as a polymerizable group (hereinafter also referred to as repeating unit A). The repeating unit A is represented by the following formula (A-1). [ka] (In formula (A-1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. L1 , R L2 , and R L3 are each independently a hydrocarbyl group having 1 to 30 carbon atoms, and R L1 , R L2 , and R L3 Any two of R may be bonded to each other to form a ring. L1 , R L2 , and R L3 When L do not bond to each other to form a ring, at least one of them has a multiple bond, an alicyclic ring, or an aromatic ring structure. A is a single bond, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond. L R is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. 1is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. n1 is an integer of 0 or 1. n2 is an integer of 1 or 2. n3 is an integer of 0 to 6, provided that, when n1=0, 1≦n2+n3≦5, and when n1=1, 1≦n2+n3≦7.

[0050] In formula (A-1), R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0051] In formula (A-1), R L1 , R L2 , and R L3 are each independently a hydrocarbyl group having 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms, and R L1 , R L2 , and R L3 Any two of R may be bonded to each other to form a ring. L1 , R L2 , and R L3 When R do not bond to each other to form a ring, at least one of them has a multiple bond, an alicyclic ring, or an aromatic ring structure. L1 , R L2 , and R L3 When they do not bond to each other to form a ring, it is preferable that at least one of them has a structure containing a multiple bond having 2 to 30 carbon atoms, an alicyclic structure having 3 to 30 carbon atoms, or an aromatic ring structure having 6 to 30 carbon atoms. In addition, -CH2- contained in the hydrocarbyl group and the heterocyclic group may be replaced with -O- or -S-.

[0052] R L1 , R L2 , and R L3 Specific examples of the acid labile group include, but are not limited to, those shown below. * represents a bond to the adjacent oxygen atom. [ka]

[0053] [ka]

[0054] [ka]

[0055] In formula (A-1), L A is a single bond, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond. Among these, a single bond, an ether bond or an ester bond is preferred, and a single bond or an ester bond is more preferred.

[0056] In formula (A-1), X L is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include an alkanediyl group and a divalent saturated cyclic hydrocarbon group. Examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom.

[0057] X L As the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a hetero atom, represented by the following formula, the following is preferred: In the following formula, * represents L A and a bond to the carbon atom of the adjacent carboxyl group. [ka]

[0058] [ka]

[0059] [ka]

[0060] Of these, X L -1~X L -3, X L -29~X L -34, X L -47~X L -50 is preferred, X L -1~X L -2, X L -29, X L -47, X L -50 is more preferable.

[0061] In formula (A-1), R 1is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. Examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom and an iodine atom being more preferred. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; saturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; unsaturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these. Of these, aryl groups are preferred. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, or some of the -CH- constituting the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, 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.

[0062] In formula (A-1), n1 is an integer of 0 or 1. When n1=0, it represents a benzene ring, and when n1=1, it represents a naphthalene ring, but from the viewpoint of solvent solubility, it is more preferable that n1=0, that is, a benzene ring.

[0063] In formula (A-1), n2 is an integer of 1 or 2.

[0064] In formula (A-1), n3 is an integer of 0 to 6, but when n1=0, 1≦n2+n3≦5, and when n1=1, 1≦n2+n3≦7. When n3≧2, multiple R 1 may be bonded to each other to form a ring structure together with the carbon atoms on the aromatic ring to which they are attached.

[0065] The repeating unit A represented by formula (A-1) is more preferably one represented by the following formula (A-2). [ka] (In the formula, R A , R L1 , R L2 , R L3 , R 1 , L A , X L , n2, and n3 are the same as above.)

[0066] The repeating unit A represented by formula (A-2) is more preferably one represented by the following formula (A-3). [ka] (In the formula, R A , R L1 , R L2 , R L3 , R 1 , n2, and n3 are the same as above.)

[0067] The repeating unit A represented by the above formulas (A-1) to (A-3) can be synthesized, for example, by the method described in paragraph

[0340] of Japanese Patent No. 7055070, but the synthesis method is not limited thereto.

[0068] Specific examples of the repeating unit A represented by the above formulas (A-1) to (A-3) include, but are not limited to, the following: A is the same as above.

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] [Repeating unit that generates acid upon exposure (repeating unit B)] The polymer of the present invention contains a repeating unit that generates acid upon exposure (hereinafter also referred to as repeating unit B). The repeating unit B is one or more 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] (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 -C(=O)-OZ 21 -, -C(=O)-NH-Z 21 -or- OZ 21 -It is. Z 21 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 3 represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-OZ 31 -It is. Z 31 Z is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. 4is a single bond or -Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -C(=O)-OZ 51 -, -C(=O)-NH-Z 51 -or- OZ 51 -It is. Z 51 R is 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. 21 and R 22 R are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 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. 1 and Rf 2 Rf are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. - is a non-nucleophilic counterion. + is an onium cation, and c is an integer of 0 to 3.

[0073] 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 -C(=O)-OZ 21 -, -C(=O)-NH-Z 21 -or- OZ 21 -It is. Z 21Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 3 represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-OZ 31 -It is. Z 31 Z is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. 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. 5 represents 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-Z 51 -or- OZ 51 -It is. Z 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group.

[0074] Z 21 , Z 31 and Z 51 The aliphatic hydrocarbylene group represented by the formula (A-1) may be linear, branched, or cyclic. L Examples of the above-mentioned examples are the same as those given in the explanation of the above.

[0075] 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.)

[0076] In formula (B-1), R 21 and R 22 R are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 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, 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. Furthermore, 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.

[0077] 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]

[0078] Examples of the cation of the repeating unit B1 include, but are not limited to, the following: A is the same as above. [ka]

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] In formula (B-1), M - is a non-nucleophilic counterion. M - 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; imidate ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion and bis(perfluorobutylsulfonyl)imide ion; and methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0083] 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]

[0084] 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 groups as those described below.

[0085] 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 moiety of 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 groups as those described below.

[0086] Specific examples of sulfonate anions represented by the non-nucleophilic counter ions include those shown below. Sumo 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]

[0087] [ka]

[0088] [ka]

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] [ka]

[0093] [ka]

[0094] 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.

[0095] 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 2In order to increase the acid strength of the generated acid, it is preferable that Rf be a fluorine atom. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. Of these, Rf 3 and Rf 4 At least one of these is preferably a trifluoromethyl group.

[0096] In formula (B-2), c is an integer of 0 to 3, with 1 being preferred.

[0097] Specific examples of the anion of the repeating unit represented by formula (B-2) include, but are not limited to, those shown below. A is the same as above

[0098] [ka]

[0099] [ka]

[0100] [ka]

[0101] [ka]

[0102] [ka]

[0103] [ka]

[0104] Specific examples of monomers for obtaining the anion of the repeating unit represented by formula (B-2) include, but are not limited to, those shown below. A is the same as above. [ka]

[0105] [ka]

[0106] [ka]

[0107] [ka]

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] [ka]

[0113] In formula (B-3), 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. 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 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. Of these, Rf 3 and Rf 4 At least one of these is preferably a trifluoromethyl group.

[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. 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. 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 sulfonium cation and iodonium cation are preferred, and the sulfonium cation represented by the following formula (cation-1) and the iodonium cation represented by the following formula (cation-2) are more preferred. That is, the repeating units that generate acid upon exposure, represented by the above (B-2), (B-3), and (B-4), are each a repeating unit represented by A + The onium cation preferably contains an onium 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 hydrocarbyl 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 each independently represents a linear, branched or cyclic hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom.

[0123] In formulas (cation-1) and (cation-2), R 11 ~R 15are 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 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. Furthermore, 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, R 11 , R 12 and R 13 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, examples of the sulfonium cation represented by formula (cation-1) include those represented by the following formula: [ka] (In the formula, the dashed line indicates, for example, R 13 )

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

[0126]

change

[0127]

change

[0128]

change

[0129]

change

[0130]

change

[0131]

change

[0132]

change

[0133]

change

[0134]

change

[0135]

change

[0136]

change

[0137]

change

[0138]

change

[0139]

change

[0140]

change

[0141]

change

[0142]

change

[0143]

change

[0144]

change

[0145]

change

[0146]

change

[0147] [ka]

[0148] [ka]

[0149] [ka]

[0150] [ka]

[0151] Examples of the iodonium cation represented by formula (cation-2) include, but are not limited to, those shown below. [ka]

[0152] [ka]

[0153] Specific structures of the repeating units represented by formulae (B-1) to (B-4) include any combination of the above-mentioned anions and cations.

[0154] As the repeating unit B, repeating units B2, B3 and B4 are preferred from the viewpoint of controlling acid diffusion, repeating units B2 and B4 are more preferred from the viewpoint of the acid strength of the generated acid, and repeating unit B2 is more preferred from the viewpoint of solvent solubility.

[0155] The polymer of the present invention is characterized by the inclusion of a repeating unit A having an acid-labile group containing a vinyl aromatic unit in the polymerizable group and a repeating unit B that generates acid upon exposure. The inclusion of a repeating unit that generates acid upon exposure in the base polymer is believed to suppress excessive acid diffusion, particularly when the acid generated after exposure is an anion-bound type bonded to the main chain of the base polymer. It is also believed that secondary electrons generated at the sensitized site contribute to the decomposition of cations without diffusing. Furthermore, the repeating unit having an acid-labile group containing a vinyl aromatic unit in the polymerizable group contributes to changes in developer solubility during the deprotection reaction after exposure. The aromatic carboxylic acid generated after the deprotection reaction is more acidic than aliphatic carboxylic acids and therefore has a high affinity with alkaline developers, allowing it to be efficiently removed during alkaline development of exposed areas. Furthermore, because the repeating unit that generates acid upon exposure has a salt structure, the glass transition temperature (Tg) of the polymer tends to be low. However, the introduction of a repeating unit having an acid-labile group containing a vinyl aromatic unit in the polymerizable group improves the rigidity of the polymer main chain. These synergistic effects simultaneously achieve high sensitivity, high contrast, and suppression of acid diffusion, making it possible to reduce LWR in line patterns and CDU in hole patterns, and also enable the formation of patterns with excellent etching resistance, making this an ideal positive resist material.

[0156] [Repeating units a1, a2] The polymer of the present invention further contains 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 repeating unit a1) other than the repeating unit represented by the above formula (A-1) and a repeating unit represented by the following formula (a-2) (hereinafter also referred to as repeating unit a2): [ka]

[0157] In formulas (a-1) and (a-2), R A is the same as above. Z A represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-OZ A1 - and ZA1 Z is a linear, branched or cyclic alkanediyl group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. B is a single bond or (main chain) -C(=O)-O-. b is a linear, branched or cyclic hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. p is an integer of 0 to 4. X A and X B are each independently an acid labile group.

[0158] 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 Nos. 2013-080033 and 2013-083821.

[0159] Typical examples of the acid labile group include those represented by the following formulae (AL-1) to (AL-3). [ka] (In the formula, the dashed lines represent bonds.)

[0160] In formulae (AL-1) and (AL-2), R' L1 and R' L2 are each independently a saturated hydrocarbyl group having 1 to 40 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The saturated hydrocarbyl group may be linear, branched, or cyclic. The saturated hydrocarbyl group preferably has 1 to 20 carbon atoms.

[0161] In formula (AL-1), a is an integer of 0 to 10, and an integer of 1 to 5 is preferred.

[0162] In formula (AL-2), R' L3 and R' L4are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms, and may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be linear, branched, or cyclic. L2 , R' L3 and R' L4 Any two of these may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0163] In formula (AL-3), R' L5 , R' L6 and R' L7 are each independently a saturated hydrocarbyl group having 1 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be linear, branched, or cyclic. L5 , R' L6 and R' L7 Any two of these may be bonded to each other together with the carbon atoms to which they are bonded to form a ring having 3 to 20 carbon atoms. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0164] Examples of the repeating unit a1 include, but are not limited to, those shown below. A and X A is the same as above. [ka]

[0165] [ka]

[0166] Examples of the repeating unit a2 include, but are not limited to, those shown below. A and X B is the same as above.

[0167] [ka]

[0168] [Repeating unit having a phenolic hydroxy group (repeating unit C)] The polymer of the present invention may contain 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 preferred. [ka]

[0169] In formula (C-1), R A is the same as above. Z B is a single bond or (main chain) -C(=O)-O-. b1 represents 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 1 to 4.

[0170] R b1 The hydrocarbyl group represented by the formula (A-1) may be saturated or unsaturated, and may be linear, branched, or cyclic. 1 Specific examples of the hydrocarbyl moiety of the hydrocarbyloxy group and the hydrocarbylcarbonyl group include those listed in the description of R 1 Examples of the above-mentioned examples are the same as those given in the explanation of the above.

[0171] Examples of the repeating unit C include, but are not limited to, those shown below. A is the same as above. [ka]

[0172] [ka]

[0173] [ka]

[0174] [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]

[0175] 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.

[0176] 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.

[0177] Examples of the repeating unit D include, but are not limited to, those shown below. A is the same as above.

[0178] [ka]

[0179] [ka]

[0180] [ka]

[0181] [ka]

[0182] [ka]

[0183] [ka]

[0184] [ka]

[0185] [ka]

[0186] [Repeating unit E] The polymer of the present invention may further contain a repeating unit E derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or derivatives thereof. Examples of the monomer that gives the repeating unit E include, but are not limited to, the following. [Chemical formula]

[0187] [Repeating unit F] The polymer of the present invention may further contain a repeating unit F derived from indane, vinylpyridine or vinylcarbazole.

[0188] In the polymer of the present invention, the content ratios of the repeating units A, a1, a2, B, C, D, E, and F are preferably​​​​​​​The weight-average molecular weight (Mw) of the polymer is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. When Mw is within this range, sufficient etching resistance is obtained, and there is no risk of a decrease in resolution due to an inability to ensure a difference in dissolution rate before and after exposure. In the present invention, Mw is a value measured in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent.

[0191] Furthermore, since the influence of Mw / Mn on the molecular weight distribution of the polymer tends to become greater as the pattern rule becomes finer, in order to obtain a resist composition that is suitable for use with fine pattern dimensions, it is preferable that Mw / Mn be a narrow dispersity of 1.0 to 2.0. If it is within this range, there will be little low-molecular-weight or high-molecular-weight polymer, and there will be no risk of foreign matter being observed on the pattern or deterioration of the pattern shape after exposure.

[0192] The polymer can be produced, for example, by heating a monomer that provides the repeating unit described above in an organic solvent with the addition of a radical polymerization initiator to carry out polymerization.

[0193] Examples of organic solvents used during polymerization include toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyrolactone (GBL). Examples of the radical polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, and lauroyl peroxide. The amount of these initiators added is preferably 0.01 to 25 mol% based on the total amount of monomers to be polymerized. The reaction temperature is preferably 50 to 150°C, more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the viewpoint of production efficiency.

[0194] The radical polymerization initiator may be added to the monomer solution and then fed to the reaction vessel. Alternatively, an initiator solution may be prepared separately from the monomer solution and then fed to the reaction vessel independently. Because radicals generated from the initiator during the waiting time may cause the polymerization reaction to proceed, resulting in the formation of ultra-high molecular weight polymers, it is preferable to prepare the monomer solution and the initiator solution independently and add them dropwise from the perspective 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. Furthermore, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol may be used in combination to adjust the molecular weight. In this case, the amount of these chain transfer agents added is preferably 0.01 to 20 mol % of the total amount of monomers to be polymerized.

[0195] In the case of a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group, such as an ethoxyethoxy group, which is easily deprotected by an acid, during polymerization, and then deprotected with a weak acid and water after polymerization. Alternatively, the hydroxy group may be substituted with an acetyl group, a formyl group, a pivaloyl group, or the like, and then subjected to alkaline hydrolysis after polymerization.

[0196] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, hydroxystyrene or hydroxyvinylnaphthalene and other monomers may be polymerized by heating in an organic solvent with the addition of a radical polymerization initiator. Alternatively, acetoxystyrene or acetoxyvinylnaphthalene may be used, and after polymerization, the acetoxy group may be deprotected by alkaline hydrolysis to form polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0197] The base that can be used in alkaline hydrolysis includes aqueous ammonia, triethylamine, etc. The reaction temperature is preferably −20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0198] The amount of each monomer in the monomer solution may be appropriately set so as to achieve the preferred content ratio of the repeating units described above.

[0199] The polymer obtained by the above-described production method may be a reaction solution obtained by a polymerization reaction as a 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, and the resulting powder may be handled as a final product. However, from the viewpoint of work efficiency and quality stability, it is preferable to handle a polymer solution obtained by dissolving the powder obtained through the purification step in a solvent as a final product.

[0200] 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 No. 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. esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono tert-butyl ether acetate; lactones such as GBL; alcohols such as diacetone alcohol (DAA); high-boiling alcohol solvents such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol; and mixed solvents thereof.

[0201] The concentration of the polymer in the polymer solution is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

[0202] The reaction solution and polymer solution are preferably filtered through a filter, which is effective in stabilizing quality by removing foreign matter and gels that may cause defects.

[0203] Examples of filter materials used in the filter filtration include fluorocarbon, cellulose, nylon, polyester, and hydrocarbon-based materials. However, in the filtration process of resist compositions, filters made of fluorocarbons, such as Teflon (registered trademark), hydrocarbons such as polyethylene and polypropylene, or nylon are preferred. The pore size of the filter can be selected appropriately depending on the target cleanliness, but is preferably 100 nm or less, more preferably 20 nm or less. These filters may be used alone or in combination. The filtration method may involve passing the solution through the filter only once, but it is more preferable to circulate the solution and filter it multiple times. The filtration process can be performed in any order and any number of times in the polymer production process. However, it is preferable to filter the reaction solution after the polymerization reaction, the polymer solution, or both.

[0204] The polymer may contain two or more polymers having different composition ratios, Mw, and molecular weight distributions.

[0205] Furthermore, the present invention can provide a resist composition containing the above polymer, and specifically can provide the chemically amplified resist composition shown below.

[0206] [Chemically amplified resist composition] The chemically amplified resist composition of the present invention comprises: (P) Polymer (G) Quencher (H) Organic solvent It is preferable that the composition contains (I) a photoacid generator other than a photoacid generator bound to a polymer chain, (J) a nitrogen-containing quencher, and (K) A surfactant that is insoluble or slightly soluble in water but soluble in an alkaline developer, and / or a surfactant that is insoluble or slightly soluble in water and an alkaline developer. and optionally, (L) Other ingredients may include:

[0207] [(G)Quencher] (G) The quencher includes an onium salt represented by the following formula (1) or (2). [ka]

[0208] In formula (1), R q1 represents a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group. q2 is a hydrogen atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom.

[0209] R q1 Specific examples of the hydrocarbyl group represented by the formula (I) 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, and a tricyclo[5.2.1.0] group. 2,6 cyclic saturated hydrocarbyl groups such as a ]decanyl group and an adamantyl group; and aryl groups such as a phenyl group, a naphthyl group and an anthracenyl group. In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms and halogen atoms, 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 acid anhydrides, haloalkyl groups, etc.

[0210] R q2 Specific examples of the hydrocarbyl group represented by R q1 In addition to the specific examples of the substituents, examples 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.

[0211] Examples of the anion of the onium salt represented by formula (1) include, but are not limited to, those shown below.

[0212] [ka]

[0213] [ka]

[0214] Examples of the anion of the onium salt represented by formula (2) include, but are not limited to, those shown below.

[0215] [ka]

[0216] [ka]

[0217] In equations (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]

[0218] Regarding formulas (cation-1) and (cation-2), A in formulas (B-2) to (B-4) + (cation-3) In R 16 ~R 19 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. 16 , R 17 , R 18 and R 19 Any two of these may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded. The hydrocarbyl group includes R 11 ~R 15 Examples of the above-mentioned examples are the same as those given in the explanation of the above.

[0219] MQ + In the onium cation represented by the formula (1), examples of the ammonium cation represented by (cation-3) include, but are not limited to, those shown below. [ka]

[0220] Specific examples of the onium salt represented by formula (1) or (2) include any combination of the anions and cations described above. These onium salts can be easily prepared by ion exchange reactions using known organic chemistry methods. For information on ion exchange reactions, see, for example, JP 2007-145797 A.

[0221] The onium salts represented by formula (1) or (2) function as quenchers in the chemically amplified resist composition of the present invention. This is because the counter anions of the onium salts are the conjugate bases of weak acids. The term "weak acid" used herein refers to an acidity that is insufficient to deprotect the acid labile groups in the acid labile group-containing units used in the polymer.

[0222] 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 counter anion that is the conjugate base of a strong acid, such as a sulfonic acid fluorinated at the α-position. Specifically, when an onium salt that generates a strong acid, such as a sulfonic acid fluorinated at the α-position, is mixed with an onium salt that generates a weak acid, such as a non-fluorinated sulfonic acid or carboxylic acid, the strong acid generated from the photoacid generator upon irradiation with high-energy radiation collides with an onium salt having an unreacted weak acid anion, releasing the weak acid through salt exchange and generating an onium salt having a strong acid anion. In this process, the strong acid is exchanged for a weak acid with lower catalytic activity, apparently deactivating the acid and enabling control of acid diffusion.

[0223] 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 thought that the weak acid generated by irradiation with high-energy rays collides with the unreacted onium salt that generates the strong acid, making it difficult to carry out 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.

[0224] When the onium salt represented by formula (1) or (2) is contained as the quencher (G), the content thereof 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 polymer (P). A quencher of component (G) within the above range is preferred because it provides good resolution and does not significantly reduce sensitivity. The onium salt represented by formula (1) or (2) may be used singly or in combination of two or more.

[0225] [(H) Organic solvent] The organic solvent for component (H) is not particularly limited as long as it can dissolve the components described above and 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 mixtures thereof.

[0226] 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 may be added to accelerate the deprotection reaction of the acetal.

[0227] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, ethyl lactate, and mixed solvents thereof are preferred because they have particularly excellent solubility for the polymer of component (P).

[0228] The amount of the organic solvent used is preferably 200 to 5,000 parts by mass, more preferably 400 to 3,000 parts by mass, relative to 80 parts by mass of the polymer (P). The organic solvent (H) can be used alone or in combination of two or more.

[0229] [(I) Photoacid generators other than those bound to polymer chains] The chemically amplified resist composition of the present invention may contain, as component (I), a photoacid generator other than the photoacid generator bonded to the polymer chain. The photoacid generator is not particularly limited as long as it is a compound that generates an acid upon exposure to high-energy rays. Suitable photoacid generators include those represented by the following formula (3): [ka]

[0230] 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 these may be bonded to each other to form a ring together with the sulfur atom to which they are attached. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (cation-1) and (cation-2): 11 ~R 15 Specific examples of the cation of the sulfonium salt represented by formula (3) include the same as those exemplified in the description of formula (1).

[0231] In formula (3), X - is an anion selected from the following formulae (3A) to (3D). [ka]

[0232] In formula (3A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). 105Examples of the above include those similar to those described below in the description of the above.

[0233] The anion represented by formula (3A) is preferably one represented by the following formula (3A'). [ka]

[0234] In formula (3A'), R 104 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 particularly preferably one having 6 to 30 carbon atoms.

[0235] 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; saturated cyclic 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 preferred. Furthermore, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the group containing a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, and the like. Examples of hydrocarbyl groups containing heteroatoms include a tetrahydrofuryl group, a methoxymethyl group, an ethoxymethyl group, a methylthiomethyl group, an acetamidomethyl group, a trifluoroethyl group, a (2-methoxyethoxy)methyl group, an acetoxymethyl group, a 2-carboxy-1-cyclohexyl group, a 2-oxopropyl group, a 4-oxo-1-adamantyl group, and a 3-oxocyclohexyl group.

[0236] Synthesis of sulfonium salts having an anion represented by formula (3A') is described in detail in JP-A Nos. 2007-145797, 2008-106045, 2009-007327, and 2009-258695. Sulfonium salts described in JP-A Nos. 2010-215608, 2012-041320, 2012-106986, and 2012-153644 are also suitable.

[0237] The anion represented by formula (3A) is M in formula (B-1). - Examples include, but are not limited to, the same as those listed above.

[0238] In formula (3B), R fb1 and R fb2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). 105 Examples include those exemplified 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 to which they are bonded (-CF2-SO2-N - -SO2-CF2-) together to form a ring, in which case, R fb1 and R fb2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0239] In formula (3C), R fc1 , R fc2 and R fc3 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). 105 Examples include those exemplified 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 , R fc2 and R fc3 When any two of these bonds are bonded to each other, the group to which they are bonded (-CF2-SO2-C - -SO2-CF2-) together to form a ring, in which case, R fc1 , R fc2 and R fc3 The group obtained by bonding any two of the above together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0240] In formula (3D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). 105 Examples of the above-mentioned examples are the same as those given in the explanation of the above.

[0241] The synthesis of sulfonium salts having an anion represented by formula (3D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

[0242] Examples of the anion represented by formula (3D) include, but are not limited to, those shown below. [ka]

[0243] 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 acid labile groups in the polymer, making it suitable for use as a photoacid generator.

[0244] Furthermore, as a photoacid generator other than the photoacid generator bonded to the polymer chain of component (I), a compound represented by the following formula (4) is also preferred. [ka]

[0245] In formula (4), R 201 and R 202 R are 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 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 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.

[0246] R201 and R 202 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6 cyclic saturated hydrocarbyl groups such as a ]decanyl group and an adamantyl group; and aryl groups such as a phenyl group, a 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 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, 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 acid anhydride, a haloalkyl group, etc.

[0247] 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, cyclopentanediyl, and cyclopentanediyl. Examples thereof include cyclic saturated hydrocarbylene groups such as a hexanediyl group, a norbornanediyl group, and an adamantanediyl group; and arylene groups such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group, an isobutylphenylene group, a sec-butylphenylene group, a tert-butylphenylene group, a naphthylene group, a methylnaphthylene group, an ethylnaphthylene group, an n-propylnaphthylene group, an isopropylnaphthylene group, an n-butylnaphthylene group, an isobutylnaphthylene group, a sec-butylnaphthylene group, and a tert-butylnaphthylene group. In addition, some of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the group containing a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. The heteroatom is preferably an oxygen atom.

[0248] In formula (4), L' A is a single bond, an ether bond, or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 203Examples of the hydrocarbylene group represented by the formula (I) include the same as those exemplified above.

[0249] In formula (4), X a , X b , X c and X d are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that X a , X b , X c and X d At least one of the groups is a fluorine atom or a trifluoromethyl group.

[0250] The photoacid generator represented by formula (4) is preferably one represented by the following formula (4'). [ka]

[0251] In formula (4'), L' A is the same as above. X e is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (3A'). 105 Examples include the same ones 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.

[0252] Examples of the photoacid generator represented by formula (4) include the same compounds as those exemplified as the photoacid generator represented by formula (4) in JP-A-2017-026980.

[0253] Among the photoacid generators, those containing an anion represented by formula (3A') or (3D) are particularly preferred because of their small acid diffusion and excellent solubility in resist solvents, and those containing an anion represented by formula (4') are particularly preferred because of their extremely small acid diffusion.

[0254] As other acid generators, onium salts represented by the following formula (5-1) or (5-2) can also be used. [ka]

[0255] In formulas (5-1) and (5-2), r is an integer that satisfies 1≦r≦3. s and t are integers that satisfy 1≦s≦5, 0≦t≦3, and 1≦s+t≦5. s is preferably an integer that satisfies 1≦s≦3, more preferably 2 or 3. t is preferably an integer that satisfies 0≦t≦2.

[0256] 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.

[0257] In formulas (5-1) and (5-2), L' 11 is a single bond, an ether bond, an ester bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0258] 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.

[0259] 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 is.

[0260] 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 hydrocarbyloxycarbonyl group having 2 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.

[0261] 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 hydrocarbyloxycarbonyl group having 2 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.

[0262] 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.

[0263] When t is 2 or more, each R 401 may be the same or different from each other.

[0264] Of these, R 401 Examples include hydroxy groups, -NR 401A -C(=O)-R 401B , -NR 401A -C(=O)-OR 401B fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, etc. are preferred.

[0265] In formulas (5-1) and (5-2), Rf 11 , Rf 12 , Rf 13 and Rf 14 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of them is a fluorine atom or a trifluoromethyl group. 11 and Rf 12 may combine with the carbon atom to which they are attached to form a carbonyl group. 13 and Rf 14 are preferably both fluorine atoms.

[0266] 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.

[0267] 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.

[0268] Also, R 402 , R 403 and R 404 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 may be any of the groups represented by R 101 , R 102 and R 103 The ring that any two of the above may form together with the sulfur atom to which they are bonded includes the same rings as those exemplified above.

[0269] 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).

[0270] Examples of the anions of the onium salts represented by formulas (5-1) and (5-2) include those exemplified as anions of the onium salts represented by formulas (5-1) and (5-2) in JP 2018-197853 A, as well as anions in which the iodine atom of the anions is replaced with a bromine atom.

[0271] When a photoacid generator other than the photoacid generator bonded to the polymer chain of component (I) is included, the content thereof is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass, relative to 80 parts by mass of the (P) polymer. When the amount of the photoacid generator other than the photoacid generator bonded to the polymer chain of 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 polymer chain of component (I) can be used alone or in combination of two or more.

[0272] [(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, thereby preventing the acid from diffusing to unexposed areas and forming a desired pattern.

[0273] 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.

[0274] Alternatively, a sulfonate sulfonium salt having a nitrogen-containing substituent may be used as a nitrogen-containing quencher. Such a compound functions as a quencher in unexposed areas, and loses its quenching ability in exposed areas by neutralizing with the acid generated by the compound itself, functioning as a so-called photodegradable base. The use of a photodegradable base can further enhance the contrast between exposed and unexposed areas. For example, JP-A Nos. 2009-109595 and 2012-046501 can be used as references for photodegradable bases.

[0275] When a nitrogen-containing quencher of 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 polymer (P). The nitrogen-containing quencher may be used singly or in combination of two or more types.

[0276] [(K) A surfactant that is insoluble or slightly soluble in water but soluble in an alkaline developer, and / or a surfactant that is insoluble or slightly 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 slightly soluble in water but soluble in an alkaline developer, and / or a surfactant that is insoluble or slightly soluble in water and an alkaline developer. Examples of such surfactants include those described in JP-A-2010-215608 and JP-A-2011-016746.

[0277] Among the surfactants described in the above publications, preferred surfactants that are insoluble or slightly soluble in water and alkaline developers include FC-4430 (manufactured by 3M), Surflon (registered trademark) S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Olfine (registered trademark) E1004 (manufactured by Nissin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and oxetane ring-opening polymers represented by the following formula (surf-1): [ka]

[0278] 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 descriptions. R is a divalent to tetravalent aliphatic group having 2 to 6 carbon atoms. Examples of the divalent aliphatic group include an ethylene group, a 1,4-butylene group, a 1,2-propylene group, a 2,2-dimethyl-1,3-propylene group, and a 1,5-pentylene group, and examples of the trivalent or tetravalent aliphatic group include the following: [ka] (In the formula, the dashed lines represent bonds and are partial structures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.)

[0279] Among these, a 1,4-butylene group, a 2,2-dimethyl-1,3-propylene group, and the like are preferred.

[0280] Rf is a trifluoromethyl group or a pentafluoroethyl group, preferably a trifluoromethyl group. m is an integer of 0 to 3, n is an integer of 1 to 4, and the sum of n and m is the valence of R, which is an integer of 2 to 4. A is 1. B is an integer of 2 to 25, preferably an integer of 4 to 20. C is an integer of 0 to 10, preferably 0 or 1. The order of the structural units in formula (surf-1) is not specified, and they may be bonded in blocks or randomly. The production of surfactants based on partially fluorinated oxetane ring-opening polymers is described in detail in the specification of U.S. Pat. No. 5,650,483, etc.

[0281] Surfactants that are insoluble or slightly soluble in water but soluble in alkaline developers have the function of reducing water penetration and leaching by orienting themselves on the surface of the resist film when a resist protective film is not used in ArF immersion lithography. Therefore, they are useful for suppressing the elution of water-soluble components from the resist film and reducing damage to the lithography equipment. They are also useful because they are soluble in aqueous alkaline development after exposure or PEB, making them less likely to become contaminants that could cause defects. Such surfactants are insoluble or slightly soluble in water but soluble in alkaline developers. They are polymeric surfactants, also known as hydrophobic resins, and are particularly preferred because they have high water repellency and improve water slippage.

[0282] Such polymer surfactants include those containing at least one repeating unit selected from the repeating units represented by the following formulas (6A) to (6E). [ka]

[0283] In formulas (6A) to (6E), R B is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 is -CH2-, -CH2CH2-, -O- or two -H groups separated from each other. s1 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. s2 R 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 hydrocarbon group or a fluorinated hydrocarbon group having 1 to 20 carbon atoms and a valence of (u+1). u is an integer of 1 to 3. R s5 are each independently a hydrogen atom or a group of the formula -C(=O)-OR sa is a group represented by R sa 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.

[0284] 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.

[0285] 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.

[0286] R s3 or R s6 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 (R), examples include an n-undecyl group, an n-dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group. s3 or R s6 Examples of the fluorinated hydrocarbyl group represented by the formula (I) include groups in which some or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbyl group have been substituted with fluorine atoms. As mentioned above, an ether bond (-O-) or a carbonyl group (-C(=O)-) may be contained between these carbon-carbon bonds.

[0287] 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.

[0288] R s4 The (u+1)-valent hydrocarbon group or fluorinated hydrocarbon group represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include groups in which u hydrogen atoms have been further removed from the aforementioned hydrocarbyl group or fluorinated hydrocarbyl group.

[0289] 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, such as 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.

[0290] Examples of the repeating units represented by formulae (6A) to (6E) include, but are not limited to, those shown below. B is the same as above. [ka]

[0291] [ka]

[0292] [ka]

[0293] [ka]

[0294] [ka]

[0295] The polymer surfactant may further contain other repeating units in addition to the repeating units represented by formulae (6A) to (6E). Examples of such 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) is preferably 20 mol % or more, more preferably 60 mol % or more, and even more preferably 100 mol %, of all repeating units.

[0296] 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.

[0297] The polymer surfactant can be synthesized by heating a monomer containing an unsaturated bond that provides the repeating units represented by formulas (6A) to (6E) and, if necessary, other repeating units, in an organic solvent with the addition of a radical initiator to polymerize the monomer. Examples of organic solvents used in polymerization include toluene, benzene, THF, diethyl ether, and dioxane. Examples of polymerization initiators include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The reaction temperature is preferably 50 to 100°C. The reaction time is preferably 4 to 24 hours. The acid labile group introduced into the monomer may be used as is, or may be protected or partially protected after polymerization.

[0298] When synthesizing the polymer 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 number of moles of the monomers to be polymerized.

[0299] When a surfactant (K) is included, its content is preferably 0.1 to 50 parts by mass, and more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the polymer (P). If 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 if 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.

[0300] [(L) Other ingredients] The chemically amplified resist composition of the present invention may contain, as other components (L), a compound that decomposes in the presence of acid to generate acid (acid amplifying compound), an organic acid derivative, a fluorine-substituted alcohol, or a compound with a Mw of 3,000 or less whose solubility in a developer changes upon the action of acid (dissolution inhibitor). Examples of the acid amplifying compound include the compounds described in JP-A-2009-269953 or JP-A-2010-215608. When the acid amplifying compound is contained, its content is preferably 0 to 5 parts by weight, more preferably 0 to 3 parts by weight, per 80 parts by weight of the (P) polymer. Within the above ranges, diffusion is easily controlled, and degradation of resolution and pattern shape does not occur. Examples of the organic acid derivative, fluorine-substituted alcohol, and dissolution inhibitor include the compounds described in JP-A-2009-269953 or JP-A-2010-215608.

[0301] [Pattern formation method] The pattern forming method of the present invention comprises: (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.

[0302] 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 coating, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.).

[0303] 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 the applied resist composition 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.

[0304] In the above step (ii), examples of high-energy rays used to expose the resist film include i-rays, KrF excimer laser light, ArF excimer laser light, electron beams (EB), and extreme ultraviolet light (EUV). Extreme ultraviolet light with a wavelength of 3 to 15 nm may also be used. This is particularly effective when electron beams and extreme ultraviolet light with a wavelength of 13.5 nm are 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 dose is preferably 1 to 300 μC / cm 2 , either directly or through a mask for forming a desired pattern. 2 , more preferably 10 to 200 μC / cm 2 The exposure can be performed by irradiating the light so that the

[0305] In addition to the usual exposure method, the immersion method can also be used, in which a liquid with a refractive index of 1.0 or higher is placed between the resist film and the projection lens. In this case, a water-insoluble protective film can also be used.

[0306] The water-insoluble protective film is used to prevent elution from the resist film and increase the water sliding property of the film surface. It can be broadly divided into two types. One is an organic solvent-removable type that requires stripping before alkaline aqueous development using an organic solvent that does not dissolve the resist film. The other is an alkaline aqueous solution-soluble type that is soluble in alkaline developer and removes the protective film along with removing the soluble portion of the resist film. The latter is particularly based on a polymer containing 1,1,1,3,3,3-hexafluoro-2-propanol residues that is insoluble in water but soluble in alkaline developer, and is preferably dissolved in an alcohol solvent with 4 or more carbon atoms, an ether solvent with 8 to 12 carbon atoms, or a mixed solvent thereof. Materials can also be prepared by dissolving the water-insoluble, alkaline developer-soluble surfactant described above in an alcohol solvent with 4 or more carbon atoms, an ether solvent with 8 to 12 carbon atoms, or a mixed solvent thereof.

[0307] After the exposure, PEB may be performed by heating on a hot plate, for example, preferably at 60 to 150° C. for 1 to 5 minutes, more preferably at 80 to 140° C. for 1 to 3 minutes.

[0308] 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, thereby obtaining a positive pattern.

[0309] In the step (iii), the developer may be, for example, an aqueous alkaline solution of tetramethylammonium hydroxide (TMAH) or the like, preferably at a concentration of 0.1 to 5% by mass, more preferably 2 to 3% by mass. The desired pattern can be formed on the substrate by developing the substrate for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, using a conventional method such as a dipping method, a puddle method, or a spray method.

[0310] 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 or 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.

[0311] Furthermore, the pattern may be formed by a double patterning method, such as a trench method in which a first exposure and etching process is performed to process an underlayer with a 1:3 trench pattern, and then a second exposure process is performed with a shifted position to form a 1:3 trench pattern, thereby forming a 1:1 pattern, or a line method in which a first underlayer with a 1:3 isolated leave pattern is processed by a first exposure and etching process, and then a second exposure process is performed with a shifted position to process a second underlayer with a 1:3 isolated leave pattern formed below the first underlayer, thereby forming a 1:1 pattern with half the pitch.

[0312] In the pattern forming method of the present invention, a negative tone development method may be used in the step (iii) in which an organic solvent is used as a developer instead of the aqueous alkaline solution to dissolve the unexposed areas but not the exposed areas, thereby obtaining a negative pattern.

[0313] The organic solvent development may be performed using the following developers: 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 methyl methyl valerate, methyl pentenoate, methyl crotonate, ethyl methyl crotonate, propyl methyl methyl valerate, propyl methyl methyl pentenoate, propyl methyl methyl crotonate, propyl methyl methyl methyl crotonate, propyl methyl methyl methyl valerate, propyl methyl methyl pentenoate, propyl methyl methyl methyl crotonate, propyl methyl methyl methyl hexano ... Examples of organic solvents 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, and 2-phenylethyl acetate. These organic solvents can be used alone or in combination of two or more. [Example]

[0314] The present invention will be specifically described below with reference to Synthesis Examples, Comparative Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples. The apparatuses used are as follows. IR: Thermo Fisher Scientific, NICOLET 6700 · 1 H-NMR: ECA-500 manufactured by JEOL Ltd.

[0315] [1] Monomer synthesis [Synthesis Example 1-1] Synthesis of Monomer A1 [ka]

[0316] Under a nitrogen atmosphere, cyclopentanone (42.0 g) was dissolved in THF (200 g), and methylmagnesium chloride (3.0 M-THF solution, 200 mL) was added dropwise to the solution in an ice bath and stirred for 1 hour. Made A solution of the acid chloride and THF (100 mL) was added dropwise in an ice bath and stirred at room temperature for 3 hours. The reaction mixture was then cooled and saturated aqueous sodium bicarbonate (250 g) was added to quench the reaction. The mixture was extracted with toluene (400 mL), subjected to standard aqueous work-up, and the solvent was evaporated. After purification by silica gel column chromatography, 74.9 g of Monomer A1 was obtained as a colorless oil (yield 65%).

[0317] IR spectrum data of monomer A1 and 1 The results of H-NMR are shown below. IR(D-ATR):ν=3089,2966,2973,1710,1630,1608,1567,1507,1464,1444,1403 ,1374,1314,1283,1201,1175,1118,1107,1016,989,915,861,783,714,453cm -1 . 1 H-NMR (600MHz in DMSO-d6): δ=7.86(2H,d),7.58(2H,d),6.79(1H,dd),5.96(1H,d),5.40(1H,d),2.17(2H,m),1.69(6H,m),1.61(3H,s)ppm.

[0318] [Synthesis Example 1-2] Synthesis of Monomer A2 [ka]

[0319] Under a nitrogen atmosphere, p-styrenecarboxylic acid (48.9 g), 1-ethylcyclopentyl chloroacetate (58.1 g), and sodium bromide (3.1 g) were dissolved in acetone (150 mL). Triethylamine (36.4 g) was then added dropwise at room temperature. After the addition, the mixture was stirred for 6 hours while maintaining the internal temperature at 50°C. The reaction mixture was then cooled, and water (75 g) was added to terminate the reaction. The mixture was extracted with toluene (300 mL), subjected to standard aqueous work-up, and the solvent was evaporated. After purification by silica gel column chromatography, 77.0 g of Monomer A2 was obtained as a colorless oil (yield 85%).

[0320] IR spectrum data of monomer A2 and 1 The results of H-NMR are shown below. IR(D-ATR):ν=2969,2878,1755,1727,1630,1608,1567,1509,1461,1422,1404,13 81,1283,1223,1175,1121,1109,1019,990,949,919,860,830,782,735,713,450cm -1 . 1 H-NMR(600MHz in DMSO-d6):δ=7.96(2H,d),7.64(2H,d),6.82(1H,dd),6.01(1H,d),5.44(1 H,d),4.81(2H,s),1.99(2H,m),1.92(2H,q),1.58(6H,m),0.84(3H,t)ppm.

[0321] [Synthesis Example 1-3] Synthesis of Monomers A3 to A10 [ka]

[0322] Monomers A3 to A10 were synthesized using the corresponding raw materials.

[0323] [2] Polymer synthesis Among the monomers used in the synthesis of the polymer, those other than the monomers A1 to A10 are as follows.

[0324] [ka]

[0325] [ka]

[0326] [ka]

[0327] [ka]

[0328] [Synthesis Example 2-1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, a flask was charged with Monomer A1 (32.1 g), Monomer a1-1 (12.9 g), Monomer B1 (42.4 g), Monomer C1 (13.7 g), 3.80 g of V-601 (Wako Pure Chemical Industries, Ltd.), and 126 g of MEK to prepare a monomer-polymerization initiator solution. In a separate flask under a nitrogen atmosphere, 46 g of MEK was charged and heated to 80°C with stirring, and the monomer-polymerization initiator solution was added dropwise over 4 hours. After the addition was completed, stirring was continued for 2 hours while maintaining the temperature of the polymerization solution at 80°C, and then the mixture was cooled to room temperature. The resulting polymerization solution was added dropwise to 2,000 g of vigorously stirred hexane, and the precipitated polymer was filtered. The resulting polymer was further washed twice with 600 g of hexane and then vacuum-dried at 50°C for 20 hours to obtain Polymer P-1 as a white powder (yield: 98.1 g, 98%). Polymer P-1 had an Mw of 9,400 and an Mw / Mn of 1.83. Note that Mw was measured in terms of polystyrene by GPC using DMF as a solvent.

[0329] [ka]

[0330] [Synthesis Examples 2-2 to 2-10, Comparative Synthesis Examples 1-1 to 1-20] Synthesis of Polymers P-2 to P-10 and Comparative Polymers CP-1 to CP-20 The polymers shown in Tables 1 and 2 were produced in the same manner as in Synthesis Example 2-1, except that the types and blending ratios of the monomers were changed.

[0331] [Table 1]

[0332] [Table 2]

[0333] [3] Preparation of resist composition [Examples 1-1 to 1-10, Comparative Examples 1-1 to 1-20] Solutions were prepared by dissolving the polymers of the present invention (P-1 to P-10), comparative polymers (CP-1 to CP-20), photoacid generators (PAG-1, PAG-2), and quenchers (SQ-1 to SQ-3, AQ-1) in the compositions shown in Tables 3 and 4 below, along with 100 ppm of FC-4430 (manufactured by 3M) as a surfactant. The solutions were then filtered through a 0.2 μm Teflon (registered trademark) filter to prepare resist compositions.

[0334] In Tables 3 and 4, the components are as follows: Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol)

[0335] Photoacid generator: PAG-1, PAG-2 [ka]

[0336] Quencher: SQ-1 to SQ-3, AQ-1 [ka]

[0337] [Table 3]

[0338] [Table 4]

[0339] [4] EUV Lithography Evaluation (1) [Examples 2-1 to 2-10, Comparative Examples 2-1 to 2-20] Each resist composition (R-1 to R-10, 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 then 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) while varying the exposure dose and focus (exposure dose pitch: 1 mJ / cm). 2 The exposure was performed with a focus pitch of 0.020 μm. 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 using a 2.38% by mass TMAH aqueous solution, followed by rinsing with a surfactant-containing rinse solution and spin drying to obtain a positive pattern. The developed LS pattern was observed using a critical dimension SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, and the sensitivity, EL, LWR, DOF, and collapse limit were evaluated according to the methods described below. The results are shown in Tables 5 and 6.

[0340] [Sensitivity evaluation] The optimum 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.

[0341] [EL Evaluation] The EL (unit: %) was calculated from the exposure amount formed within a range of ±10% (16.2 to 19.8 nm) of the 18 nm space width in the LS pattern using 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 produce LS pattern with line width of 18nm and pitch of 36nm

[0342] [LWR rating] E op The dimensions of the LS pattern obtained by irradiation at 10 points in the longitudinal direction of the line were measured, and the LWR was calculated as three times the standard deviation (σ) (3σ). The smaller this value, the less roughness and the more uniform the line width pattern obtained.

[0343] [DOF evaluation] For the evaluation of the depth of focus, the focus range formed within a range of ±10% (16.2 to 19.8 nm) of the 18 nm dimension of the LS pattern was determined. The larger this value, the wider the depth of focus.

[0344] [Table 5]

[0345] [Table 6]

[0346] The results shown in Tables 5 and 6 confirm that the resist composition of the present invention has good sensitivity and is excellent in various lithography performances.

[0347] [5] EUV Lithography Evaluation (2) [Examples 3-1 to 3-10, Comparative Examples 3-1 to 3-20] Each resist composition (R-1 to R-10, CR-1 to CR-20) shown in Tables 3 and 4 was spin-coated onto a Si substrate with a 20 nm thick silicon-containing spin-on hard mask (SHB-A940, manufactured by Shin-Etsu Chemical Co., Ltd.) (43% silicon by mass) and pre-baked at 105°C for 60 seconds using a hot plate to produce a 50 nm thick resist film. This was then exposed using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple-pole illumination, 46 nm pitch on the wafer, +20% bias hole pattern mask), subjected to PEB for 60 seconds using a hot plate at the temperatures listed in Tables 7 and 8, and developed for 30 seconds in a 2.38% by mass TMAH aqueous solution to form a 23 nm hole pattern. Using a Hitachi High-Technologies Corporation CD-SEM (CG6300), the exposure dose when a hole dimension of 23 nm was formed was measured and used as the sensitivity. 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.

[0348] [Table 7]

[0349] [Table 8]

[0350] The results shown in Tables 7 and 8 confirm that the resist compositions of the present invention have good sensitivity and excellent CDU.

[0351] [6] Dry etching resistance evaluation [Examples 4-1 to 4-10, Comparative Examples 4-1 to 4-20] 2 g of each of the polymers (P-1 to P-10) and comparative polymers (CP-1 to CP-20) shown in Tables 1 and 2 was dissolved in 10 g of cyclohexanone and filtered through a 0.2 μm filter. The polymer solution was spin-coated onto a Si substrate to form a film with a thickness of 300 nm, and evaluated under the following conditions.

[0352] Etching test with CHF3 / CF4 gas: The difference in film thickness of the polymer film before and after etching was determined using a dry etching apparatus TE-8500P manufactured by Tokyo Electron Limited. The etching conditions are as follows: Chamber pressure 40.0Pa RF power 1,000W Gap 9mm CHF3 gas flow rate: 30 mL / min CF4 gas flow rate: 30 mL / min Ar gas flow rate: 100 mL / min Time 60sec In this evaluation, a film with a small difference in film thickness, that is, a film with a small reduction in film thickness, is shown to have resistance to dry etching. The results of the dry etching resistance are shown in Table 9.

[0353] [Table 9]

[0354] From the results shown in Table 9, it was confirmed that the polymer of the present invention has excellent dry etching resistance in CHF3 / CF4-based gases.

[0355] The present specification includes the following aspects. [1]: A polymer (P) that generates an acid upon exposure and whose solubility in a developer is changed by the action of the acid, the polymer comprising: a repeating unit represented by the following formula (A-1); a repeating unit that generates an acid upon exposure and is represented by any one or more of the following formulas (B-1), (B-2), (B-3), and (B-4); and a repeating unit represented by the following formula (a-1) or (a-2) other than the repeating unit represented by formula (A-1): [ka] (In formula (A-1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. L1 , R L2 , and R L3 are each independently a hydrocarbyl group having 1 to 30 carbon atoms, and R L1 , R L2 , and R L3 Any two of R may be bonded to each other to form a ring. L1 , R L2 , and R L3 When L do not bond to each other to form a ring, at least one of them has a multiple bond, an alicyclic ring, or an aromatic ring structure. A is a single bond, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond. L R is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. 1 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. n1 is an integer of 0 or 1. n2 is an integer of 1 or 2. n3 is an integer of 0 to 6, but when n1=0, 1≦n2+n3≦5, and when n1=1, 1≦n2+n3≦7. 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 -C(=O)-OZ 21 -, -C(=O)-NH-Z 21 -or- OZ 21-It is. Z 21 Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 3 represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-OZ 31 -It is. Z 31 Z is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. 4 is a single bond or -Z 41 -C(=O)-O-. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -C(=O)-OZ 51 -, -C(=O)-NH-Z 51 -or- OZ 51 -It is. Z 51 R is 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. 21 and R 22 R are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 21 and R 22 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 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. 1 and Rf 2 Rf are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms.- is a non-nucleophilic counterion. + is an onium cation, and c is an integer of 0 to 3. [ka] (In the formula, R A is the same as above. Z A represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-OZ A1 - and Z A1 Z is a linear, branched or cyclic alkanediyl group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. B is a single bond or (main chain) -C(=O)-O-. b is a linear, branched or cyclic hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. p is an integer of 0 to 4. X A and X B are each independently an acid labile group. [2]: The polymer according to the above [1], wherein the repeating unit represented by the formula (A-1) is a repeating unit represented by the following formula (A-2): [ka] (In the formula, R A , R L1 , R L2 , R L3 , R 1 , L A , X L , n2, and n3 are the same as above.) [3]: The polymer according to the above [2], wherein the repeating unit represented by the formula (A-2) is a repeating unit represented by the following formula (A-3): [ka] (In the formula, R A , R L1 , R L2 , R L3 , R 1, n2, and n3 are the same as above.) [4]: The repeating units (B-2), (B-3), and (B-4) that generate an acid upon exposure are each selected from the group consisting of A + The polymer according to any one of the above [1] to [3], characterized in that the polymer contains an onium cation represented by the following formula (cation-1) or (cation-2) as the onium cation: [ka] (In the formula, R 11 , R 12 and R 13 each independently represents a linear, branched or cyclic hydrocarbyl 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 each independently represents a linear, branched or cyclic hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. [5]: The polymer according to any one of [1] to [4] above, further comprising a repeating unit represented by the following formula (C-1) in the polymer (P): [ka] (In the formula, R A , Z B is the same as above. R b1 represents a halogen atom, a cyano group, or a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, which may contain a heteroatom. m represents an integer of 1 to 4, k represents an integer of 0 to 3, and m+k represents an integer of 1 to 4. [6]: The polymer according to any one of [1] to [5] above, further comprising a repeating unit represented by the following formula (D-1) in the polymer (P): [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 carbonate bond, a lactone ring, a sultone ring, and a carboxylic acid anhydride. [7]: A resist composition comprising any one of the polymers described above in [1] to [6]. [8]: The resist composition according to the above [7], further comprising an organic solvent. [9]: The resist composition according to the above [7] or [8], further comprising a photoacid generator other than the structural unit of the polymer (P) that generates an acid upon exposure.

[10] : The resist composition according to any one of [7] to [9] above, further comprising a quencher.

[11] : The resist composition according to any one of [7] to

[10] above, further comprising 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.

[12] : A pattern forming method comprising the steps of: forming a resist film on a substrate using the resist composition according to any one of [7] to

[11] above; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

[13] : The pattern forming method according to

[12] above, wherein the high energy beam is i-ray, KrF excimer laser beam, ArF excimer laser beam, electron beam or extreme ultraviolet ray having a wavelength of 3 to 15 nm.

[14] : The pattern forming method according to

[12] or

[13] , characterized in that an alkaline aqueous solution is used as the developer to dissolve exposed areas and obtain a positive pattern in which unexposed areas do not dissolve.

[15] : The pattern forming method according to

[12] or

[13] above, characterized in that an organic solvent is used as the developer to dissolve unexposed areas, thereby obtaining a negative pattern in which exposed areas do not dissolve.

[0356] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A polymer (P) that generates an acid upon exposure and whose solubility in a developer is changed by the action of the acid, characterized in that the polymer contains a repeating unit represented by the following formula (A-1); a repeating unit that generates an acid upon exposure and is represented by any one or more of the following formulas (B-1), (B-2), (B-3), and (B-4): 【Chemical 1】 (In formula (A-1), R Ａ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Ｌ１ , R Ｌ２ , and R Ｌ３ are each independently a hydrocarbyl group having 1 to 30 carbon atoms, and R Ｌ１ , R Ｌ２ , and R Ｌ３ Any two of R may be bonded to each other to form a ring. Ｌ１ , R Ｌ２ , and R Ｌ３ When L do not bond to each other to form a ring, at least one of them has a multiple bond, an alicyclic ring, or an aromatic ring structure. Ａ is a single bond, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond. Ｌ R is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. １ is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. n1 is an integer of 0 or 1. n2 is an integer of 1 or 2. n3 is an integer of 0 to 6, but when n1=0, 1≦n2+n3≦5, and when n1=1, 1≦n2+n3≦7. In formulas (B-1) to (B-4), R Ａ is the same as above. １ is a single bond or a phenylene group. ２ is -C(=O)-O-Z ２１ -, -C(=O)-NH-Z ２１ -or-O-Z ２１ - is. Z ２１ represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. ３ represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-O-Z ３１ - is. Z ３１ is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. ４ is a single bond or -Z ４１ -C(=O)-O-. Z ４１ is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 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. Z ５１ R is 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. ２１ and R ２２ R are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. ２１ and R ２２ and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 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. １ and Rf ２ are each independently a fluorine atom or a fluorinated alkyl group having 1 to 6 carbon atoms. ３ and Rf ４ are each independently a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. － is a non-nucleophilic counterion. ＋ is an onium cation. c is an integer of 0 to 3. 【Chemistry 2】 (In the formula, R Ａ is the same as above. Ａ represents a single bond, a phenylene group, a naphthylene group, or (main chain) -C(=O)-O-Z Ａ１ - and Z Ａ１ Z is a linear, branched or cyclic alkanediyl group having 1 to 10 carbon atoms, which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, a phenylene group or a naphthylene group. Ｂ is a single bond or (main chain) -C(=O)-O-. ｂ is a linear, branched or cyclic hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. p is an integer of 0 to 4. X Ａ and X Ｂ are each independently an acid labile group.

2. 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 3】 (In the formula, R Ａ , R Ｌ１ , R Ｌ２ , R Ｌ３ , R １ , L Ａ , X Ｌ , n2, and n3 are the same as above.)

3. The polymer according to claim 2, wherein the repeating unit represented by formula (A-2) is a repeating unit represented by the following formula (A-3): 【Chemistry 4】 (In the formula, R Ａ , R Ｌ１ , R Ｌ２ , R Ｌ３ , R １ , n2, and n3 are the same as above.)

4. The repeating units (B-2), (B-3), and (B-4) that generate an acid upon exposure are each selected from the group consisting of A ＋ 2. The polymer according to claim 1, wherein the onium cation is an onium cation represented by the following formula (cation-1) or (cation-2): 【Chemistry 5】 (In the formula, R １１ , R １２ and R １３ each independently represents a linear, branched or cyclic hydrocarbyl 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 each independently represents a linear, branched or cyclic hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom.

5. The polymer according to claim 1, further comprising a repeating unit represented by the following formula (C-1) in the polymer (P): 【Chemistry 6】 (In the formula, R Ａ , Z Ｂ is the same as above. ｂ１ represents a halogen atom, a cyano group, or a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, or a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, which may contain a heteroatom; m represents an integer of 1 to 4, k represents an integer of 0 to 3, and m+k represents an integer of 1 to 4.

6. The polymer according to claim 1, further comprising a repeating unit represented by the following formula (D-1) in the polymer (P): 【Chemistry 7】 (In the formula, R Ａ , Z Ａ is the same as above. 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 carbonate bond, a lactone ring, a sultone ring, and a carboxylic acid anhydride.

7. A resist composition comprising the polymer according to any one of claims 1 to 6.

8. 8. The resist composition according to claim 7, further comprising an organic solvent.

9. 8. The resist composition according to claim 7, further comprising a photoacid generator other than the structural unit of the polymer (P) that generates an acid upon exposure.

10. 8. The resist composition according to claim 7, further comprising a quencher.

11. 8. The resist composition according to claim 7, further comprising a surfactant that is insoluble or slightly soluble in water but soluble in an alkaline developer, and / or a surfactant that is insoluble or slightly soluble in water and an alkaline developer.

12. 10. A pattern forming method comprising the steps of: forming a resist film on a substrate using the resist composition according to claim 7; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

13. 13. The pattern forming method according to claim 12, wherein the high-energy beam is i-line, KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light having a wavelength of 3 to 15 nm.

14. 13. The pattern forming method according to claim 12, wherein an alkaline aqueous solution is used as the developer to dissolve exposed areas and to obtain a positive pattern in which unexposed areas do not dissolve.

15. 13. The pattern forming method according to claim 12, wherein an organic solvent is used as the developer to dissolve the unexposed areas, thereby obtaining a negative pattern in which the exposed areas do not dissolve.

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