Resist composition and method for forming pattern

Abstract

To provide a resist composition which has high sensitivity, high resolution, small edge roughness and dimensional variation, and enables a good pattern shape to be materialized after exposure, and to provide a method for forming pattern.SOLUTION: A resist composition is provided which contains resin (A) containing a repeating unit generating acid by exposure, a photodegradable quencher having specific structure, and organic solvent, wherein at least one of them has a sulfonium cation represented by the following formula (1).SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] As LSIs become more highly integrated and faster, pattern rules are becoming increasingly miniaturized. This is due to the increasing popularity of 5G high-speed communications and artificial intelligence (AI), which require high-performance devices to process these. The most advanced miniaturization technology is extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm, which is currently used to mass-produce 5 nm node devices. Furthermore, the use of EUV lithography is being considered for next-generation 3 nm node devices and the next-generation 2 nm node devices.

[0003] Recently used EUV light sources have low output but high energy due to their short wavelength, resulting in a very small number of photons during exposure. As a result, the amount of photoacid generator that is exposed to EUV light is smaller than that during DUV exposure, resulting in uneven acid distribution within the resist film. This photon shot noise is known to cause a deterioration in LWR performance (Non-Patent Document 1).

[0004] In order to improve the performance degradation caused by such a small number of photons, it is effective to add a photoacid generator with high photosensitivity. For example, Patent Documents 1 and 2 propose onium salts of sulfonium cations substituted with fluorine atoms.

[0005] As miniaturization progresses, image blurring due to acid diffusion has become a problem. To ensure resolution in fine patterns with dimensions of 45 nm and smaller, it has been suggested that controlling acid diffusion is important, in addition to improving dissolution contrast, as has been proposed previously (Non-Patent Document 2). However, because chemically amplified resist materials increase sensitivity and contrast through acid diffusion, attempts to minimize acid diffusion by lowering the post-exposure bake (PEB) temperature or shortening the time result in significant decreases in sensitivity and contrast.

[0006] The triangle trade-off relationship between sensitivity, resolution, and edge roughness is shown. To improve resolution, it is necessary to suppress acid diffusion, but as the acid diffusion distance becomes shorter, sensitivity decreases.

[0007] It is effective to suppress acid diffusion by adding an acid generator that generates bulky acid. Therefore, it has been proposed to incorporate repeating units derived from onium salts having polymerizable unsaturated bonds into a polymer. In this case, the polymer also functions as an acid generator (polymer-bound acid generator). Patent Document 3 proposes sulfonium salts and iodonium salts having polymerizable unsaturated bonds that generate specific sulfonic acids. Patent Document 4 proposes sulfonium salts in which sulfonic acids are directly linked to the main chain.

[0008] Onium salts of weak acids have been proposed as acid diffusion control agents for suppressing the diffusion of strong acid components generated from photoacid generators. When a strong acid and a weak acid onium salt are mixed, ion exchange occurs, replacing the weak acid with the strong acid onium salt. Because the replaced weak acid does not cause acid decomposition of the base polymer, the weak acid onium salt functions as a quencher. Quenchers that generate carboxylic acids as weak acids have been proposed, such as sulfonium salts of salicylic acid, β-hydroxycarboxylic acids (Patent Document 5), salicylic acid derivatives (Patent Documents 6 and 7), iodine-containing salicylic acid (Patent Document 8), and α-fluorocarboxylic acids (Patent Documents 9 and 10).

[0009] As described above, conventional techniques have a problem in that they do not provide a resist composition or a pattern formation method that simultaneously satisfies the three performance requirements of sensitivity, resolution, and edge roughness required for mass production of 5 nm node devices using extreme ultraviolet (EUV) lithography, which has been in demand in recent years. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent No. 6442370 [Patent Document 2] Patent No. 6586303 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-045311 [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-178317 [Patent Document 5] International Publication No. 2018 / 159560 [Patent Document 6] Japanese Patent Publication No. 2020-203984 [Patent Document 7] Japanese Patent Publication No. 2020-91404 [Patent Document 8] Japanese Patent Publication No. 2022-77505 [Patent Document 9] Japanese Patent Application Laid-Open No. 2015-054833 [Patent Document 10] Patent Publication No. 2021-91666 [Non-patent literature]

[0011] [Non-Patent Document 1] SPIE Vol.3331 p531(1998) [Non-patent document 2] SPIE Vol.6520 65203L-1(2007) Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resist composition and a pattern forming method that have higher sensitivity and higher resolution than conventional resist materials, have small edge roughness and dimensional variation, and produce a favorable pattern shape after exposure. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention provides: A resist composition comprising a resin (A) containing a repeating unit represented by the following formula (a1) that generates an acid upon exposure, a photodegradable quencher represented by the following formula (b1), and an organic solvent, wherein M1 in the formula (a1) + , M2 in the formula (b1) + and at least one of the above is a sulfonium cation represented by the following formula (1): [ka] (In the formula, R a1 are each independently a hydrogen atom or a methyl group. a1 is a single bond or an ester bond. a1 Rf is a single bond or a divalent organic group having 1 to 20 carbon atoms which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that Rf 1 ~Rf 4 At least one of M1 is a fluorine atom. + is a sulfonium cation. [ka] (In the formula, Rb is an organic group having 1 to 30 carbon atoms which may have a substituent. M2 + is a sulfonium cation. [ka] [In the formula, R 1 R is a fluorine atom, an iodine atom, or a perfluoroalkyl group. 2 , R 3 are each independently a fluorine atom or a perfluoroalkyl group. l is an integer of 0 to 3, m is an integer of 1 to 3, and n is an integer of 1 to 3. When l, m, and n are integers of 2 or more, R 1 , R 2 , R 3 may be the same or different, provided that the structure of formula (1) contains at least two fluorine atoms. 2 or R 3 is a fluorine atom, at least one fluorine atom is meta-substituted relative to the sulfur atom.

[0014] Such a resist composition has high sensitivity and high resolution, has little edge roughness and dimensional variation, and produces a favorable pattern shape after exposure.

[0015] The photodegradable quencher represented by the formula (b1) is preferably represented by the following formula (b1-1): [ka] (In the formula, Rb' is an organic group having 1 to 22 carbon atoms which may have a substituent, and may contain an ester bond, an ether bond, an amide bond, a lactone ring, a sultone ring, an aromatic cyclic group, an aliphatic cyclic group, a hydroxyl group, an alkoxy group, a fluoroalkyl group, a nitro group, a cyano group, a trifluoromethoxy group, a carbonyl group, an amino group, an alkylamino group, a fluorine atom, a bromine atom, or an iodine atom. M2 + is a sulfonium cation.

[0016] Such a resist composition functions as a quencher (B1-1), which is an excellent acid diffusion controller for suppressing the diffusion of a strong acid component generated from a photoacid generator. This action makes it possible to simultaneously enhance the efficiency of acid generation upon exposure and minimize the acid diffusion distance, thereby simultaneously achieving high sensitivity, excellent line edge roughness (LWR), and dimensional variation.

[0017] The resin (A) is preferably a resin further containing a repeating unit represented by the following formula (a2). [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. 1 R is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and an ester bond, an ether bond, or a lactone ring. 11 is an acid labile group.

[0018] When such a resin is used, the dissolution contrast is improved due to the repeating units in which the hydrogen atom of the introduced carboxy group is substituted with an acid labile group, thereby achieving high sensitivity and significantly increasing the contrast in alkaline dissolution rate before and after exposure.

[0019] The repeating unit represented by the formula (a1) is preferably represented by the following formula (a1-1): [ka] (In the formula, R a1 are each independently a hydrogen atom or a methyl group. a1 is a single bond or an ester bond. L1 is a single bond or a divalent linking group which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. L2 is a single bond or a divalent linking group which may contain an ester bond or an ether bond. Rf 1 ~Rf 4are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that Rf 1 ~Rf 4 At least one of M1 is a fluorine atom. k is an integer of 0 to 4. + is a sulfonium cation.

[0020] A repeating unit having such a structure provides high sensitivity, high resolution, small edge roughness and dimensional variations, and a good pattern shape after exposure.

[0021] The repeating unit represented by the formula (a1) is preferably represented by the following formula (a1-2): [ka] (R in the formula a1 are each independently a hydrogen atom or a methyl group. L1 is a single bond or a divalent linking group which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. L2 is a single bond or a divalent linking group which may contain an ester bond or an ether bond. Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that Rf 1 ~Rf 4 At least one of M1 is a fluorine atom. k is an integer of 0 to 4. + is a sulfonium cation.

[0022] If the polymerizable group of the resin is a methacrylate, the polymer main chain becomes rigid, increasing the glass transition temperature. As a result, the thermal diffusion of the strong acid component generated from the photoacid generator is suppressed, and resolution is improved.

[0023] The anion moieties of the formula (a1) and formula (b1) preferably contain an iodine atom.

[0024] If such an anion moiety contains an iodine atom, the iodine atom has a high absorption rate for EUV light and a high ability to efficiently generate secondary electrons from photons given by EUV exposure, thereby achieving high sensitivity and high resolution.

[0025] M1 in the formula (a1) + and M2 in formula (b1) + are preferably both sulfonium cations represented by formula (1).

[0026] Such sulfonium cations can enhance electron accepting properties and efficiently convert secondary electrons generated by exposure into an acid, thereby achieving high sensitivity and high resolution.

[0027] In the formula (1), it is preferable that l is an integer of 1 to 3.

[0028] Such sulfonium cations can further enhance electron accepting properties and can efficiently convert secondary electrons generated by exposure to acid, thereby achieving more preferable high sensitivity and high resolution.

[0029] The cation represented by the formula (1) preferably contains an iodine atom.

[0030] Iodine atoms have high absorption of EUV light and can efficiently generate secondary electrons from photons emitted by EUV exposure, achieving high sensitivity and high resolution. Furthermore, the iodine atoms bond to the triarylsulfonium cation without a linker, allowing for efficient photochemical reactions.

[0031] 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.

[0032] Such a pattern formation method can provide a pattern formation method with high sensitivity and high resolution, and with little line edge roughness (LWR) and dimensional variation (CDU).

[0033] In this case, the high energy radiation used in the exposure step is preferably i-rays, KrF excimer laser light, ArF excimer laser light, electron beams, or extreme ultraviolet rays with a wavelength of 3 to 15 nm.

[0034] Such a pattern formation method can simultaneously satisfy three requirements, namely high sensitivity, high resolution, low edge roughness (LWR), and low dimension variation (CDU), in a more preferable manner, and can be applied to the mass production of 5 nm node devices, which have fine patterns that correspond to the increasing integration and speed of LSIs, and further to the mass production of next-generation 3 nm node and next-generation 2 nm node devices. [Effects of the Invention]

[0035] As described above, the resist composition and pattern formation method of the present invention can provide a resist composition and pattern formation method that exhibit high sensitivity and high resolution, and that exhibit small line edge roughness (LWR) and critical dimension variation (CDU). It can also provide a resist composition that exhibits high sensitivity and a significantly high alkaline dissolution rate contrast before and after exposure. Furthermore, the pattern formation method can be applied to the mass production of 5-nm node devices, which are fine patterns that correspond to the increasing integration and speed of LSIs, as well as the mass production of next-generation 3-nm node and next-generation 2-nm node devices. DETAILED DESCRIPTION OF THE INVENTION

[0036] As described above, there has been a need for the development of a resist composition and pattern formation method that meets the recent demand for high sensitivity and high resolution, while also exhibiting low line roughness (LWR) and small dimension variation (CDU).

[0037] The present inventors have conducted extensive research to obtain resist compositions that meet the recent demand for high sensitivity and high resolution, while also exhibiting low line roughness (LWR) and small dimension variation (CDU). As a result, they have discovered that it is necessary to increase the efficiency of acid generation upon exposure and to shorten the acid diffusion distance to the utmost, and that this can be achieved by incorporating a photosensitive resin containing a sulfonium cation having a specific structure and / or a photodegradable quencher containing a sulfonium cation having a specific structure.

[0038] Furthermore, the present inventors have found that by introducing a repeating unit in which the hydrogen atom of a carboxy group is substituted with an acid labile group in order to improve the dissolution contrast, it is possible to obtain a resist composition which has high sensitivity, a significantly high alkali dissolution rate contrast before and after exposure, high sensitivity, a high effect of suppressing acid diffusion, high resolution, and excellent pattern shape after exposure with little edge roughness or dimensional variation, and which is particularly suitable as a fine pattern forming material for the manufacture of VLSIs or photomasks, and have completed the present invention.

[0039] That is, the present invention provides: A resist composition comprising a resin (A) containing a repeating unit represented by the following formula (a1) that generates an acid upon exposure, a photodegradable quencher represented by the following formula (b1), and an organic solvent, wherein M1 in the formula (a1) + , M2 in the formula (b1) + and at least one of the above is a sulfonium cation represented by the following formula (1): [ka] (In the formula, R a1 are each independently a hydrogen atom or a methyl group. a1 is a single bond or an ester bond. a1 Rf is a single bond or a divalent organic group having 1 to 20 carbon atoms which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. 1 ~Rf 4are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that Rf 1 ~Rf 4 At least one of M1 is a fluorine atom. + is a sulfonium cation. [ka] (In the formula, Rb is an organic group having 1 to 30 carbon atoms which may have a substituent. M2 + is a sulfonium cation. [ka] [In the formula, R 1 R is a fluorine atom, an iodine atom, or a perfluoroalkyl group. 2 , R 3 are each independently a fluorine atom or a perfluoroalkyl group. l is an integer of 0 to 3, m is an integer of 1 to 3, and n is an integer of 1 to 3. When l, m, and n are integers of 2 or more, R 1 , R 2 , R 3 may be the same or different, provided that the structure of formula (1) contains at least two fluorine atoms. 2 or R 3 is a fluorine atom, at least one fluorine atom is meta-substituted relative to the sulfur atom.

[0040] The present invention will be described in detail below, but the present invention is not limited thereto.

[0041] [Base polymer] (Repeating unit (a1)) The base polymer (A) (resin (A)) in the resist composition of the present invention contains a repeating unit represented by the following formula (a1) that generates acid upon exposure. [ka] (In the formula, R a1 are each independently a hydrogen atom or a methyl group.a1 is a single bond or an ester bond. a1 Rf is a single bond or a divalent organic group having 1 to 20 carbon atoms which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that Rf 1 ~Rf 4 At least one of M1 is a fluorine atom. + is a sulfonium cation.

[0042] Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom. 3 and Rf 4 At least one of Rf is preferably a fluorine atom. 3 and Rf 4 More preferably, both of are fluorine atoms.

[0043] The repeating unit (a1) is a photoacid generator (PAG) consisting of a sulfonate anion and a sulfonium cation. By incorporating the PAG as a repeating unit into the polymer, the diffusion distance of the strong acid component is reduced, thereby suppressing image blur and improving resolution.

[0044] The anion moiety of the repeating unit (a1) may be a polymerizable group having a styrene structure. Specific examples of the anion moiety of the repeating unit (a1) include, but are not limited to, the following:

[0045] [ka]

[0046] [ka]

[0047] [ka]

[0048] [ka]

[0049] In addition, the anion moiety of the repeating unit (a1) preferably has a polymerizable group having a methacrylate structure.

[0050] Specific examples of the anion moiety of the repeating unit (a1) include, but are not limited to, those shown below.

[0051] [ka]

[0052] [ka]

[0053] [ka]

[0054] [ka]

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] [ka]

[0059] [ka]

[0060] [ka]

[0061] [ka]

[0062] When the polymerizable group is a methacrylate, the polymer main chain becomes rigid, increasing the glass transition temperature, which in turn suppresses the thermal diffusion of the strong acid component generated from the photoacid generator, improving resolution.

[0063] (M1 of repeating unit (a1) + ) M1 in the repeating unit (a1) + is a sulfonium cation, preferably containing an iodine atom. Iodine atoms have high absorption properties for EUV light and can efficiently generate secondary electrons from photons emitted by EUV exposure, which is expected to result in high sensitivity and high resolution.

[0064] M1 of the repeating unit (a1) + Specific examples include, but are not limited to, the following: [ka]

[0065] [ka]

[0066]

change

[0067]

change

[0068]

change

[0069]

change

[0070]

change

[0071]

change

[0072]

change

change

[0073]

change

[0074]

change

[0075]

change

[0076] [ka]

[0077] [ka]

[0078] (Sulfonium cation represented by general formula (1)) M1 in the repeating unit (a1) + is preferably a sulfonium cation represented by the following formula (1):

[0079] [ka] [In the formula, R 1 R is a fluorine atom, an iodine atom, or a perfluoroalkyl group. 2 , R 3 are each independently a fluorine atom or a perfluoroalkyl group. l is an integer of 0 to 3, m is an integer of 1 to 3, and n is an integer of 1 to 3. When l, m, and n are integers of 2 or more, R 1 , R 2 , R 3 may be the same or different, provided that the structure of formula (1) contains at least two fluorine atoms. 2 or R 3 is a fluorine atom, at least one fluorine atom is meta-substituted relative to the sulfur atom.

[0080] Such sulfonium cations can enhance electron-accepting properties and efficiently convert secondary electrons generated by exposure into acid, which is expected to result in high sensitivity and high resolution.

[0081] In formula (1), l is an integer of 0 to 3, preferably an integer of 1 or 2, and more preferably l=1. m is an integer of 1 to 3, preferably an integer of 1 or 2, and more preferably m=2. n is an integer of 1 to 3, preferably an integer of 1 or 2, and more preferably m=2.

[0082] The number of fluorine atoms contained in formula (1) is preferably three or more, and more preferably four or more.

[0083] R in formula (1) 2 , R 3 is preferably a fluorine atom or a trifluoromethyl group, more preferably a fluorine atom.

[0084] The sulfonium cation represented by formula (1) preferably contains one or more iodine atoms, and more preferably contains only one.

[0085] R in formula (1) 1 is preferably a fluorine atom or an iodine atom, more preferably an iodine atom.

[0086] Iodine atoms have high absorption of EUV light and can efficiently generate secondary electrons from photons emitted by EUV exposure, which is expected to result in high sensitivity and high resolution. Furthermore, the iodine atoms are bound to the triarylsulfonium cation without a linker, which is expected to result in efficient photochemical reactions.

[0087] In general, compounds with many iodine atoms can enhance absorption of EUV light, but they can also have reduced solubility in casting solvents and developers, which can lead to deterioration of lithography performance.

[0088] A compound having iodine atoms in both the anion moiety and the cation moiety of the repeating unit (a1) can increase EUV absorption efficiency without impairing solvent solubility, and is therefore expected to improve lithography performance.

[0089] Specific examples of the sulfonium cation represented by formula (1) include, but are not limited to, those shown below.

[0090] [ka]

[0091] [ka]

[0092] [ka]

[0093] The electron-accepting ability of triarylsulfonium cations can be estimated by calculating the LUMO (Lowest Unoccupied Molecular Orbital) level of the molecule. The LUMO level can be calculated using DFT (density functional theory). Software that can perform DFT calculations includes, for example, Gaussian 16.

[0094] Using Gaussian 16, DFT calculations were performed using B3LYP as the functional and 6-31G(d) as the basis set, and the LUMO level of the triphenylsulfonium cation was found to be -4.72 eV. Since the LUMO level energy of the sulfonium cation represented by formula (1) is lower than -4.72 eV, it is believed that the electron-accepting property is high and the acid generation efficiency is improved.

[0095] The LUMO level of the sulfonium cation represented by the formula (1) is lower than −4.72 eV, preferably −5.00 eV or lower, more preferably −5.10 eV or lower, more preferably −5.20 eV or lower, and still more preferably −5.30 eV or lower.

[0096] On the other hand, since the storage stability deteriorates as the LUMO level decreases, the LUMO level of the sulfonium cation represented by the formula (1) is preferably −5.50 eV or higher, more preferably −5.45 eV or higher, more preferably −5.40 eV or higher, and still more preferably −5.35 eV or higher.

[0097] An example of the LUMO level calculation for the sulfonium cation represented by formula (1) is shown below, but preferred structures are not limited to these. The LUMO calculation was performed using Gaussian 16, with the B3LYP functional and 6-31G(d) basis set. An effective core potential approximation was performed for the iodine atom, and LanL2DZ was used as the basis set.

[0098] [ka]

[0099] The repeating unit represented by the formula (a1) is preferably represented by the following formula (a1-1): [ka] (In the formula, R a1 are each independently a hydrogen atom or a methyl group. a1 is a single bond or an ester bond. L1 is a single bond or a divalent linking group which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. L2 is a single bond or a divalent linking group which may contain an ester bond or an ether bond. Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that Rf 1 ~Rf 4 At least one of M1 is a fluorine atom. k is an integer of 0 to 4. + is a sulfonium cation.

[0100] A repeating unit having such a structure provides high sensitivity, high resolution, small edge roughness and dimensional variations, and a good pattern shape after exposure.

[0101] The repeating unit represented by the formula (a1) is preferably represented by the following formula (a1-2): [ka] (R in the formula a1 are each independently a hydrogen atom or a methyl group. L1 is a single bond or a divalent linking group which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. L2 is a single bond or a divalent linking group which may contain an ester bond or an ether bond. Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that Rf 1 ~Rf 4 At least one of M1 is a fluorine atom. k is an integer of 0 to 4. + is a sulfonium cation.

[0102] If the polymerizable group of the resin is a methacrylate, the polymer main chain becomes rigid, increasing the glass transition temperature. As a result, the thermal diffusion of the strong acid component generated from the photoacid generator is suppressed, and resolution is improved.

[0103] (Repeating unit represented by formula (a2)) The base polymer preferably further contains a repeating unit represented by the following formula (a2):

[0104] [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. 1 R is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and an ester bond, an ether bond, or a lactone ring.11 is an acid labile group.

[0105] If the base polymer contains a repeating unit represented by formula (a2) in which the hydrogen atom of the carboxy group is substituted with an acid labile group, the resist composition will have excellent high dissolution contrast.

[0106] Specific examples of the monomer that gives (a2) include, but are not limited to, the following: A and R 11 has the same meaning as defined in the above formula (a2).

[0107] [ka]

[0108] [ka]

[0109] The base polymer may also contain a repeating unit (a2-2) in which the hydrogen atom of a phenolic hydroxyl group is substituted with an acid labile group.

[0110] [ka] In the above general formula (a2-2), R A is R in formula (a2). A The same applies to the preferred examples. 2 is a single bond or an ester bond. 3 is a single bond, an ether bond, or an ester bond. 11 is an acid labile group. 12 R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 13is a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of whose carbon atoms may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4, provided that 1≦a+b≦5.

[0111] Specific examples of the monomer that provides the repeating unit (a2-2) include, but are not limited to, the following: A and R 11 is R in formula (a2). A and R 11 is synonymous with. [ka]

[0112] R 11 The acid labile group represented by the formula (AL-1) may be selected from a variety of groups, and examples thereof include those represented by the following formulae (AL-1) to (AL-3). [ka]

[0113] In formula (AL-1), c is an integer of 0 to 6. L1 is a tertiary hydrocarbyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, a trihydrocarbylsilyl group in which each hydrocarbyl group is a saturated hydrocarbyl group having 1 to 6 carbon atoms, a carbonyl group, or a saturated hydrocarbyl group having 4 to 20 carbon atoms containing an ether bond or an ester bond, or a group represented by formula (AL-3).

[0114] R L1The tertiary hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be branched or cyclic. Specific examples thereof include a tert-butyl group, a tert-pentyl group, a 1,1-diethylpropyl group, a 1-ethylcyclopentyl group, a 1-butylcyclopentyl group, a 1-ethylcyclohexyl group, a 1-butylcyclohexyl group, a 1-ethyl-2-cyclopentenyl group, a 1-ethyl-2-cyclohexenyl group, and a 2-methyl-2-adamantyl group. Examples of the trihydrocarbylsilyl group include a trimethylsilyl group, a triethylsilyl group, and a dimethyl-tert-butylsilyl group. The saturated hydrocarbyl group containing a carbonyl group, an ether bond, or an ester bond may be linear, branched, or cyclic, but is preferably cyclic. Specific examples thereof include a 3-oxocyclohexyl group, a 4-methyl-2-oxooxan-4-yl group, a 5-methyl-2-oxoxolan-5-yl group, a 2-tetrahydropyranyl group, and a 2-tetrahydrofuranyl group.

[0115] Examples of the acid labile group represented by formula (AL-1) include a tert-butoxycarbonyl group, a tert-butoxycarbonylmethyl group, a tert-pentyloxycarbonyl group, a tert-pentyloxycarbonylmethyl group, a 1,1-diethylpropyloxycarbonyl group, a 1,1-diethylpropyloxycarbonylmethyl group, a 1-ethylcyclopentyloxycarbonyl group, a 1-ethylcyclopentyloxycarbonylmethyl group, a 1-ethyl-2-cyclopentenyloxycarbonyl group, a 1-ethyl-2-cyclopentenyloxycarbonylmethyl group, a 1-ethoxyethoxycarbonylmethyl group, a 2-tetrahydropyranyloxycarbonylmethyl group, and a 2-tetrahydrofuranyloxycarbonylmethyl group.

[0116] Further, examples of the acid labile group represented by formula (AL-1) include groups represented by the following formulae (AL-1)-1 to (AL-1)-10. [ka] (In the formula, the dashed lines represent bonds.)

[0117] In formulae (AL-1)-1 to (AL-1)-10, c is the same as defined above. L8 are each independently a saturated hydrocarbyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. L9 is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. L10 is a saturated hydrocarbyl group having 2 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic.

[0118] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10. The saturated hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, and an n-octyl group.

[0119] In formula (AL-2), R L2 is a hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10, which may contain a heteroatom. Here, the hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples of the hydrocarbyl group include saturated hydrocarbyl groups having 1 to 18 carbon atoms, and some of the hydrogen atoms in these groups may be substituted with hydroxy groups, alkoxy groups, oxo groups, amino groups, alkylamino groups, etc. Specific examples of such substituted saturated hydrocarbyl groups include those shown below. [ka] (In the formula, the dashed lines represent bonds.)

[0120] R L2 and R L3 and R L2 and R L4 and, or RL3 and R L4 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, or together with the carbon atom and oxygen atom, and in this case, R L2 and R L3 , R L2 and R L4 , or R L3 and R L4 are each independently an alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10. The ring obtained by combining these groups preferably has 3 to 10 carbon atoms, more preferably 4 to 10 carbon atoms.

[0121] Among the acid labile groups represented by formula (AL-2), linear or branched ones include, but are not limited to, those represented by the following formulae (AL-2)-1 to (AL-2)-69, in which the dashed lines represent bonds. [ka]

[0122] [ka]

[0123] [ka]

[0124] [ka]

[0125] Among the acid labile groups represented by formula (AL-2), examples of cyclic groups include tetrahydrofuran-2-yl, 2-methyltetrahydrofuran-2-yl, tetrahydropyran-2-yl, and 2-methyltetrahydropyran-2-yl groups.

[0126] Further, examples of the acid labile group include groups represented by the following formula (AL-2a) or (AL-2b): The base polymer may be inter- or intramolecularly crosslinked by the acid labile group. [ka] (In the formula, the dashed lines represent bonds.)

[0127] In formula (AL-2a) or (AL-2b), R L11 and R L12 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 8 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. L11 and R L12 may be bonded to each other to form a ring together with the carbon atoms to which they are attached, in which case R L11 and R L12 are each independently an alkanediyl group having 1 to 8 carbon atoms. L13 are each independently a saturated hydrocarbylene group having 1 to 10 carbon atoms. The saturated hydrocarbylene group may be linear, branched, or cyclic. d and e are each independently an integer of 0 to 10, preferably an integer of 0 to 5, and f is an integer of 1 to 7, preferably an integer of 1 to 3.

[0128] In formula (AL-2a) or (AL-2b), L A is an (f+1)-valent aliphatic saturated hydrocarbon group having 1 to 50 carbon atoms, an (f+1)-valent alicyclic saturated hydrocarbon group having 3 to 50 carbon atoms, an (f+1)-valent aromatic hydrocarbon group having 6 to 50 carbon atoms, or an (f+1)-valent heterocyclic group having 3 to 50 carbon atoms. In addition, some of the carbon atoms of these groups may be substituted with heteroatom-containing groups, and some of the hydrogen atoms bonded to carbon atoms of these groups may be substituted with hydroxy groups, carboxy groups, acyl groups, or fluorine atoms. A As L, saturated hydrocarbon groups such as saturated hydrocarbylene groups having 1 to 20 carbon atoms, trivalent saturated hydrocarbon groups, and tetravalent saturated hydrocarbon groups, and arylene groups having 6 to 30 carbon atoms are preferred. The saturated hydrocarbon groups may be linear, branched, or cyclic.B is -C(=O)-O-, -NH-C(=O)-O- or -NH-C(=O)-NH-.

[0129] Examples of the divalent linking group represented by formula (AL-2a) or (AL-2b) include groups represented by the following formulae (AL-2)-70 to (AL-2)-77. [ka] (In the formula, the dashed lines represent bonds.)

[0130] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms such as oxygen, sulfur, nitrogen, or fluorine atoms. 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, cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, cyclic unsaturated hydrocarbyl groups having 3 to 20 carbon atoms, and aryl groups having 6 to 10 carbon atoms. In addition, R L5 and R L6 and R L5 and R L7 and, or R L6 and R L7 may be bonded to each other to form an alicyclic ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.

[0131] Examples of the group represented by formula (AL-3) include a tert-butyl group, a 1,1-diethylpropyl group, a 1-ethylnorbornyl group, a 1-methylcyclopentyl group, a 1-isopropylcyclopentyl group, a 1-ethylcyclopentyl group, a 1-methylcyclohexyl group, a 2-(2-methyl)adamantyl group, a 2-(2-ethyl)adamantyl group, and a tert-pentyl group.

[0132] Further, examples of the group represented by formula (AL-3) include groups represented by the following formulae (AL-3)-1 to (AL-3)-19. [ka] (In the formula, the dashed lines represent bonds.)

[0133] In formulas (AL-3)-1 to (AL-3)-19, R L14 are each independently a saturated hydrocarbyl group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms. L15 and R L17 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms. L16 is an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. The aryl group is preferably a phenyl group. R F is a fluorine atom or a trifluoromethyl group, and g is an integer of 1 to 5.

[0134] Further examples of the acid labile group include groups represented by the following formula (AL-3)-20 or (AL-3)-21: The acid labile group may cause intramolecular or intermolecular crosslinking of the polymer. [ka] (In the formula, the dashed lines represent bonds.)

[0135] In formulas (AL-3)-20 and (AL-3)-21, R L14 is the same as above. R L18 is a (h+1)-valent saturated hydrocarbylene group having 1 to 20 carbon atoms or a (h+1)-valent arylene group having 6 to 20 carbon atoms, and may contain a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. The saturated hydrocarbylene group may be linear, branched, or cyclic. h is an integer of 1 to 3.

[0136] Examples of the monomer that provides the repeating unit containing the acid labile group represented by formula (AL-3) include (meth)acrylate esters containing the exo structure represented by formula (AL-3)-22 below. [ka]

[0137] In formula (AL-3)-22, R A is the same as above. R Lc1 R is a saturated hydrocarbyl group having 1 to 8 carbon atoms or an optionally substituted aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. Lc2 ~R Lc11 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 15 carbon atoms which may contain a heteroatom. Examples of the heteroatom include an oxygen atom. Examples of the hydrocarbyl group include an alkyl group having 1 to 15 carbon atoms and an aryl group having 6 to 15 carbon atoms. R Lc2 and R Lc3 and R Lc4 and R Lc6 and R Lc4 and R Lc7 and R Lc5 and R Lc7 and R Lc5 and R Lc11 and R Lc6 and R Lc10 and R Lc8 and R Lc9 and, or R Lc9 and R Lc10 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, and in this case, the group participating in the bond is a hydrocarbylene group having 1 to 15 carbon atoms which may contain a heteroatom. Lc2 and R Lc11 and R Lc8 and R Lc11 and, or R Lc4 and R Lc6 The term "a" means that adjacent carbon atoms may bond to each other without any intervening bond to form a double bond. This formula also represents an enantiomer.

[0138] Here, examples of the monomer that gives the repeating unit represented by formula (AL-3)-22 include those described in JP-A-2000-327633. Specific examples include, but are not limited to, the following. In the following formula, RA is the same as above. [ka]

[0139] Examples of monomers that provide repeating units containing an acid labile group represented by formula (AL-3) include (meth)acrylic acid esters containing a furandiyl group, a tetrahydrofurandiyl group, or an oxanorbornanediyl group represented by the following formula (AL-3)-23. [ka]

[0140] In formula (AL-3)-23, R A is the same as above. R Lc12 and R Lc13 are each independently a hydrocarbyl group having 1 to 10 carbon atoms. Lc12 and R Lc13 may be bonded to each other to form an alicyclic ring together with the carbon atoms to which they are attached. Lc14 is a furandiyl group, a tetrahydrofurandiyl group, or an oxanorbornanediyl group. Lc15 is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be linear, branched, or cyclic. Specific examples thereof include saturated hydrocarbyl groups having 1 to 10 carbon atoms.

[0141] Specific examples of the monomer that provides the repeating unit represented by formula (AL-3)-23 include, but are not limited to, the following: A is the same as above, Ac is an acetyl group, and Me is a methyl group. [ka]

[0142] [ka]

[0143] (Repeating unit d) The base polymer may further contain a repeating unit d having an adhesive group selected from a hydroxy group, a carboxy group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, a hemiacetal group, an ether bond, an ester bond, a sulfonate ester bond, a cyano group, an amide group, -OC(=O)-S-, and -OC(=O)-NH-.

[0144] Specific examples of the monomer that provides the repeating unit d include, but are not limited to, the following: A is the same as above. [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] [ka]

[0149] [ka]

[0150] [ka]

[0151] [ka]

[0152] (Repeating unit e) The base polymer may further contain a repeating unit e that does not contain an amino group but contains an iodine atom. Specific examples of the monomer that provides the repeating unit e include, but are not limited to, the following. In the following formula, R A is the same as above. [ka]

[0153] [ka]

[0154] (Repeating unit f) The base polymer may contain a repeating unit f other than the repeating units described above. Examples of the repeating unit f include those derived from styrene, vinylnaphthalene, indene, acenaphthylene, coumarin, and coumarone.

[0155] In the base polymer, the content ratios of repeating units a1, a2, d, e, and f are preferably 0≦a1<1.0, 0≦a2<1.0, 0≦d≦0.8, 0≦e≦0.8, and 0≦f≦0.8, more preferably 0.001≦a1≦0.8, 0.001≦a2≦0.8, 0≦d≦0.5, 0≦e≦0.4, and 0≦f≦0.4, and even more preferably 0.005≦a1≦0.7, 0.005≦a2≦0.7, 0≦d1≦0.4, 0≦e≦0.3, and 0≦f≦0.3, where a1+a2+d+e+f=1.0.

[0156] To synthesize the base polymer, for example, a monomer that provides the repeating unit described above may be polymerized by heating in an organic solvent with the addition of a radical polymerization initiator.

[0157] Examples of organic solvents used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, propylene glycol monomethyl ether, γ-butyrolactone, and mixed solvents thereof. Examples of polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The polymerization temperature is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0158] When a monomer containing a hydroxy group is copolymerized, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid, such as an ethoxyethoxy group, during polymerization, and then deprotected with a weak acid and water after polymerization. Alternatively, the hydroxy group may be substituted with an acetyl group, a formyl group, a pivaloyl group, or the like, and then subjected to alkaline hydrolysis after polymerization.

[0159] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group may be deprotected by the alkaline hydrolysis to give hydroxystyrene or hydroxyvinylnaphthalene.

[0160] 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.

[0161] The base polymer preferably has a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) using THF as a solvent of 1,000 to 500,000, more preferably 2,000 to 30,000. If the Mw is too small, the resist material will have poor heat resistance, while if it is too large, the alkali solubility will be reduced, making it more likely to experience a footing phenomenon after pattern formation.

[0162] Furthermore, the molecular weight distribution (Mw / Mn) of the base polymer is preferably 1.0 to 2.0, more preferably 1.0 to 1.7, and even more preferably a narrow distribution of 1.0 to 1.5. If the molecular weight distribution is within this range, there is no risk of foreign matter being observed on the pattern after exposure or deterioration of the pattern shape due to the presence of low-molecular-weight or high-molecular-weight polymers, and such a resist material is suitable for use with fine pattern dimensions.

[0163] The base polymer may contain two or more polymers with different composition ratios, Mw, or Mw / Mn. Alternatively, a polymer containing the repeating unit a may be blended with a polymer not containing the repeating unit a.

[0164] [Photodegradable quencher] The resist material of the present invention contains a photodecomposable quencher represented by the following formula (b1). [ka] (In the formula, Rb is an organic group having 1 to 30 carbon atoms which may have a substituent. M2 + is a sulfonium cation.

[0165] (b1) is a sulfonium salt of a carboxylic acid, which suppresses acid diffusion by undergoing ion exchange with the strong acid component generated from the photoacid generator.

[0166] In formula (b1), R b Preferably, the alkyl group contains an aromatic cyclic group or a cyclic hydrocarbon group, more preferably an aromatic cyclic group.

[0167] In formula (b1), R b Preferably, the compound contains one or more iodine atoms, more preferably two or more iodine atoms.

[0168] The photodegradable quencher represented by the formula (b1) is preferably represented by the following formula (b1-1):

[0169] [ka] (In the formula, Rb' is an organic group having 1 to 22 carbon atoms which may have a substituent, and may contain an ester bond, an ether bond, an amide bond, a lactone ring, a sultone ring, an aromatic cyclic group, an aliphatic cyclic group, a hydroxyl group, an alkoxy group, a fluoroalkyl group, a nitro group, a cyano group, a trifluoromethoxy group, a carbonyl group, an amino group, an alkylamino group, a fluorine atom, a bromine atom, or an iodine atom. M2 + is a sulfonium cation.

[0170] In formula (b1-1), R b‘ is preferably one containing an aromatic cyclic group. In formula (b1-1), R b‘ Preferably, the compound contains one or more iodine atoms, more preferably two or more iodine atoms.

[0171] Iodine atoms have a high absorption rate for EUV light and can efficiently generate secondary electrons from photons given by EUV exposure, which is expected to result in high sensitivity and high resolution.

[0172] Specific examples of the anion moiety of the repeating units (b1) and (b1-1) include, but are not limited to, those shown below. [ka]

[0173] [ka]

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] [ka]

[0178] Examples of the cationic moiety of the photodegradable quencher represented by the formula (b1) include, but are not limited to, the same as those exemplified as the cationic moiety of the repeating unit (a1).

[0179] M2 of the photodegradable quencher represented by formula (b1) + The sulfonium cation represented by the formula (1) is preferably one represented by the formula (1) below. [ka] [In the formula, R 1 R is a fluorine atom, an iodine atom, or a perfluoroalkyl group. 2 , R 3 are each independently a fluorine atom or a perfluoroalkyl group. l is an integer of 0 to 3, m is an integer of 1 to 3, and n is an integer of 1 to 3. When l, m, and n are integers of 2 or more, R 1 , R 2 , R 3 may be the same or different, provided that the structure of formula (1) contains at least two fluorine atoms. 2 or R 3is a fluorine atom, at least one fluorine atom is meta-substituted relative to the sulfur atom.

[0180] Examples of the sulfonium cation of the photodegradable quencher represented by the formula (1) include, but are not limited to, the same as those exemplified as the preferred cation moiety of the repeating unit (a1).

[0181] Generally, compounds having many iodine atoms can enhance absorption of EUV light, but can also lead to deterioration of lithography performance due to reduced solubility in casting solvents and developers. Compounds having iodine atoms in both the anion and cation moieties of the photodegradable quencher (b1) can enhance EUV absorption efficiency without impairing solvent solubility, and are therefore expected to improve lithography performance.

[0182] The cationic moiety M of the repeating unit (a1) contained in the resist composition of the present invention 1+ and the cationic moiety M of the photodegradable quencher (b1). 2+ and (b) a compound having a structure represented by the formula (1) above. Such a composition is believed to be capable of increasing the amount of secondary electrons generated by EUV exposure, and also capable of efficiently utilizing the generated secondary electrons to generate acid, thereby improving the chemical contrast between exposed and unexposed areas.

[0183] Such a composition provides a resist with high sensitivity, high resolution, and little edge roughness and dimensional variation.

[0184] [Acid generator] The positive resist material of the present invention may further contain an acid generator (hereinafter also referred to as an additive-type acid generator) that generates a strong acid. The term "strong acid" as used herein refers to a compound having sufficient acidity to induce a deprotection reaction of the acid-labile groups of the base polymer. Examples of the acid generator include compounds (photoacid generators) that generate an acid in response to actinic rays or radiation. The photoacid generator may be any compound that generates an acid upon exposure to high-energy rays, but preferred are those that generate sulfonic acids, imide acids, or methide acids. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimides, and oxime-O-sulfonate-type acid generators. Specific examples of photoacid generators include those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A.

[0185] Furthermore, as the photoacid generator, a sulfonium salt represented by the following formula (1-1) or an iodonium salt represented by the following formula (1-2) can also be suitably used. [ka]

[0186] In formulas (1-1) and (1-2), R 101 ~R 105 are each independently a monovalent hydrocarbon 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 bonded. The monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include those similar to those described above.

[0187] In formulas (1-1) and (1-2), X - is an anion selected from the following formulae (1A) to (1D). [ka]

[0188] In formula (1A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). 107 Examples of the hydrocarbyl group represented by the formula (I) include the same groups as those described below.

[0189] The anion represented by formula (1A) is preferably one represented by the following formula (1A'). [ka]

[0190] In formula (1A'), R 106 is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 107 is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, 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.

[0191] R 107The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosanyl; cyclic saturated hydrocarbyl groups such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecanyl, tetracyclododecanylmethyl, and dicyclohexylmethyl; unsaturated 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.

[0192] In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the group containing a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. Specific 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.

[0193] Synthesis of sulfonium salts containing anions represented by formula (1A') is described in detail in JP-A Nos. 2007-145797, 2008-106045, 2009-7327, and 2009-258695. Sulfonium salts described in JP-A Nos. 2010-215608, 2012-41320, 2012-106986, and 2012-153644 are also suitable.

[0194] Examples of the anion represented by formula (1A) include the same anions as those exemplified as the anion represented by formula (1A) in JP 2018-197853 A.

[0195] In formula (1B), R fb1 and R fb2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). 107 Examples include those exemplified in the explanation of R. fb1 and R fb2 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 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.

[0196] In formula (1C), R fc1 , R fc2 and R fc3 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A').107 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 and R fc2 are groups that are bonded together and bonded to each other (-CF2-SO2-C - -SO2-CF2-) together to form a ring, in which case, R fc1 and R fc2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0197] In formula (1D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). 107 Examples of the above-mentioned examples are the same as those given in the explanation of the above.

[0198] The synthesis of sulfonium salts containing anions represented by formula (1D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

[0199] Examples of the anion represented by formula (1D) include the same anions as those exemplified as the anion represented by formula (1D) in JP 2018-197853 A.

[0200] Although the photoacid generator containing the anion represented by formula (1D) does not have a fluorine atom at the α-position of the sulfo group, it has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave the acid labile groups in the base polymer, making it suitable for use as a photoacid generator.

[0201] Furthermore, a photoacid generator represented by the following formula (2) can also be suitably used. [ka]

[0202] In formula (2), 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 and R 202 or R 201 and R 203 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring may be any of the groups represented by R 101 and R 102 and the sulfur atom to which they are bonded to form a ring, the same rings as those exemplified above can be mentioned.

[0203] R 201 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]. 2,6cyclic saturated hydrocarbyl groups such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, a tert-butylnaphthyl group, an anthracenyl group, and the like. In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the group containing a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, and the like.

[0204] 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 or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the group containing a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. The heteroatom is preferably an oxygen atom.

[0205] In formula (2), L 1 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 R203 Examples of the hydrocarbylene group represented by the formula (I) include the same as those exemplified above.

[0206] In formula (2), 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.

[0207] In formula (2), k is an integer of 0 to 3.

[0208] The photoacid generator represented by formula (2) is preferably one represented by the following formula (2'). [ka]

[0209] In formula (2'), L 1 is the same as above. R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). 107 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.

[0210] Examples of the photoacid generator represented by formula (2) include the same compounds as those exemplified as the photoacid generator represented by formula (2) in JP-A-2017-026980.

[0211] Among the photoacid generators, those containing an anion represented by formula (1A') or (1D) are particularly preferred because of their small acid diffusion and excellent solubility in resist solvents. Also, those represented by formula (2') are particularly preferred because of their extremely small acid diffusion.

[0212] Furthermore, the photoacid generator may also be a sulfonium salt or iodonium salt having an anion containing an aromatic ring substituted with an iodine atom or a bromine atom, such as those represented by the following formula (3-1) or (3-2): [ka]

[0213] In formulas (3-1) and (3-2), p is an integer that satisfies 1≦p≦3. q and r are integers that satisfy 1≦q≦5, 0≦r≦3, and 1≦q+r≦5. q is preferably an integer that satisfies 1≦q≦3, more preferably 2 or 3. r is preferably an integer that satisfies 0≦r≦2.

[0214] In formulas (3-1) and (3-2), X BI represents an iodine atom or a bromine atom, and when q is 2 or more, they may be the same or different.

[0215] In formulas (3-1) and (3-2), 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.

[0216] In formulas (3-1) and (3-2), L 12 represents a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and represents a trivalent or tetravalent linking group having 1 to 20 carbon atoms when p is 2 or 3, and the linking group may contain a chlorine atom, bromine atom, iodine atom, oxygen atom, sulfur atom or nitrogen atom.

[0217] In formulas (3-1) and (3-2), R 401 represents 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, an unsaturated hydrocarbyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 10 carbon atoms, a saturated hydrocarbyloxycarbonyloxy group having 1 to 10 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, an unsaturated 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, a carbonyl group, an oxycarbonyl group, or an ether bond, or -NR 401A -C(=O)-R 401B or -NR 401A -C(=O)-OR 401B R 401A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 401B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbyloxycarbonyl group, saturated hydrocarbylcarbonyl group, and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 may be the same or different from each other.

[0218] Of these, R 401 Examples include hydroxy groups, -NR 401A -C(=O)-R401B , -NR 401A -C(=O)-OR 401B fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group, etc. are preferred.

[0219] In formulas (3-1) and (3-2), Rf 11 ~Rf 14 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of them is a fluorine atom or a trifluoromethyl group. 11 , Rf 12 may further be an oxygen atom, and Rf 1 When is an oxygen atom, Rf 2 is also an oxygen atom, which forms a carbonyl group together with the carbon atom to which it is attached. 13 and Rf 14 are preferably both fluorine atoms.

[0220] In formulas (3-1) and (3-2), R 402 , R 403 , R 404 , R 405 and R 406 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 101 ~R 105 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. In addition, some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the carbon atoms of these groups may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate group, or a sulfonate ester bond. 402 and R 403may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is the same as that described for R in the explanation of formula (1-1). 101 and R 102 and the sulfur atom to which they are bonded to form a ring, the same rings as those exemplified above can be mentioned.

[0221] Examples of the cation of the sulfonium salt represented by formula (3-1) include the same as those exemplified as the cation of the sulfonium salt represented by formula (1-1). Examples of the cation of the iodonium salt represented by formula (3-2) include the same as those exemplified as the cation of the iodonium salt represented by formula (1-2).

[0222] Specific examples of the anion of the onium salt represented by formula (3-1) or (3-2) include, but are not limited to, the following: BI is the same as above. [ka]

[0223] [ka]

[0224] [ka]

[0225] [ka]

[0226] [ka]

[0227] [ka]

[0228]

change

[0229]

change

[0230]

change

[0231]

change

[0232]

change

[0233]

change

[0234]

change

[0235]

change

[0236]

change

[0237]

change

[0238]

change

[0239] [ka]

[0240] [ka]

[0241] [ka]

[0242] [ka]

[0243] [ka]

[0244] [ka]

[0245] [Organic solvents] The resist composition of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the components described above and below. Examples of such organic solvents include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol, and the like, as described in paragraphs

[0144] and

[0145] of JP-A-2008-111103, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol monoethyl ether. Examples of suitable solvents include ethers such as ethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono-tert-butyl ether acetate; lactones such as γ-butyrolactone; and mixed solvents thereof.

[0246] In the resist material of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, and more preferably 200 to 8,000 parts by mass, per 100 parts by mass of the base polymer.

[0247] [Other ingredients] In addition to the above-mentioned components, surfactants, dissolution inhibitors, etc. may be added in appropriate combinations depending on the purpose to prepare a resist composition.

[0248] Examples of the surfactant include those described in paragraphs

[0165] and

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

[0249] By adding a dissolution inhibitor, the difference in dissolution rate between the exposed and unexposed areas can be further increased, and the resolution can be further improved.

[0250] Examples of the dissolution inhibitor include compounds having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800, containing two or more phenolic hydroxy groups in the molecule, in which the hydrogen atoms of the phenolic hydroxy groups have been substituted with acid labile groups in an overall ratio of 0 to 100 mol %, and compounds containing carboxy groups in the molecule, in which the hydrogen atoms of the carboxy groups have been substituted with acid labile groups in an overall ratio of 50 to 100 mol %. Specific examples include compounds in which the hydrogen atoms of the hydroxyl groups or carboxyl groups of bisphenol A, trisphenol, phenolphthalein, cresol novolak, naphthalenecarboxylic acid, adamantanecarboxylic acid, and cholic acid have been substituted with acid labile groups, as described, for example, in paragraphs

[0155] to

[0178] of JP 2008-122932 A.

[0251] The content of the dissolution inhibitor is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, relative to 100 parts by mass of the base polymer. The dissolution inhibitors can be used alone or in combination of two or more.

[0252] The resist composition of the present invention may contain a water-repellency improver to improve the water-repellency of the resist surface after spin coating. The water-repellency improver can be used in immersion lithography without a topcoat. Examples of the water-repellency improver include polymeric compounds containing fluorinated alkyl groups and polymeric compounds containing a specific 1,1,1,3,3,3-hexafluoro-2-propanol residue, and more preferably those exemplified in JP-A Nos. 2007-297590 and 2008-111103. The water-repellency improver must be soluble in an organic solvent developer. The water-repellency improver containing the specific 1,1,1,3,3,3-hexafluoro-2-propanol residue described above has good solubility in the developer. As a water-repellency improver, polymeric compounds containing repeating units containing amino groups or amine salts are highly effective in preventing acid evaporation during post-exposure baking (PEB) and preventing poor hole pattern opening after development. The water repellency improver may be used alone or in combination of two or more. In the resist material of the present invention, the content of the water repellency improver is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the base polymer.

[0253] The resist composition of the present invention may also contain an acetylene alcohol. Examples of the acetylene alcohol include those described in paragraphs

[0179] to

[0182] of JP-A No. 2008-122932. In the resist composition of the present invention, the content of the acetylene alcohol is preferably 0 to 5 parts by mass per 100 parts by mass of the base polymer.

[0254] [Pattern formation method] When the resist composition of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied.

[0255] For example, the resist material of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflective coating, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., to a coating thickness of 0.01 to 2 μm. This is then prebaked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0256] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, EB, EUV, X-rays, soft X-rays, excimer laser, γ-rays, and synchrotron radiation. When ultraviolet radiation, far ultraviolet radiation, EUV, X-rays, soft X-rays, excimer laser, γ-rays, and synchrotron radiation are used as the high-energy radiation, a mask for forming a desired pattern is used, and the exposure dose is preferably 1 to 200 mJ / cm. 2 approximately, more preferably 10 to 100 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 100 μC / cm 2 approximately, more preferably 0.5 to 50 μC / cm 2 The resist material of the present invention is particularly suitable for fine patterning using high-energy rays such as i-rays, KrF excimer lasers, ArF excimer lasers, EB, EUV, X-rays, soft X-rays, γ-rays, and synchrotron radiation, and is particularly suitable for fine patterning using EB or EUV.

[0257] After the exposure, PEB may be performed on a hot plate, preferably at 50 to 150° C. for 10 seconds to 30 minutes, more preferably at 60 to 130° C. for 30 seconds to 20 minutes.

[0258] After exposure or PEB, the substrate is developed using a developer such as an aqueous alkaline solution of 0.1 to 10 mass %, preferably 2 to 5 mass %, of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), or the like, for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by a conventional method such as dipping, puddling, or spraying. The irradiated portions dissolve in the developer, while the unexposed portions do not, forming the desired positive pattern on the substrate.

[0259] Negative development can also be performed to obtain a negative pattern by organic solvent development using a positive resist material containing a base polymer containing an acid labile group. The developer used in this case can be 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, Examples of the organic solvent include methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents can be used alone or in combination of two or more.

[0260] After the development is completed, the resist film is rinsed. A solvent that is miscible with the developer but does not dissolve the resist film is preferred as the rinse solution. Preferred examples of such solvents include alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms.

[0261] Specific examples of alcohols having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, and 3-hexanol. , 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, and the like.

[0262] Examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, and di-n-hexyl ether.

[0263] Examples of alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Examples of alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Examples of alkynes having 6 to 12 carbon atoms include hexyne, heptine, octyne, etc.

[0264] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0265] Rinsing can reduce the occurrence of resist pattern collapse and defects. Rinsing is not always necessary, and not performing rinsing can reduce the amount of solvent used.

[0266] The developed hole or trench pattern can also be shrunk using thermal flow, RELACS, or DSA. A shrink agent is applied to the hole pattern, and the diffusion of an acid catalyst from the resist layer during baking causes crosslinking of the shrink agent on the surface of the resist, resulting in adhesion of the shrink agent to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds. Excess shrink agent is removed, and the hole pattern is shrunk. [Example]

[0267] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0268] [1] Polymer synthesis The PAG monomers 1 to 8 that provide the repeating unit represented by formula (a1) and the acid labile group monomers (ALG monomers) 1 to 4 that provide the repeating unit represented by formula (a2) used in the synthesis of the polymer are as follows: The Mw of the polymer is a polystyrene-equivalent value measured by GPC using THF as the solvent. [ka]

[0269] [ka]

[0270] [Synthesis Example 1-1] Synthesis of Polymer 1 A 2L flask was charged with 6.0g of PAG monomer 1, 7.9g of ALG monomer 4, 5.2g of 4-hydroxystyrene, a monomer that provides a structure corresponding to repeating unit d, and 40g of THF as a solvent. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was carried out for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The resulting white solid was dried under reduced pressure at 60°C to obtain polymer 1. The composition of polymer 1 was: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0271] [Synthesis Example 1-2] Synthesis of Polymer 2 A 2L flask was charged with 7.1g of PAG monomer 2, 7.3g of ALG monomer 2, 5.2g of 3-hydroxystyrene, a monomer that provides a structure corresponding to repeating unit d, and 40g of THF as a solvent. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was carried out for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The resulting white solid was dried under reduced pressure at 60°C to obtain polymer 2. The composition of polymer 2 was: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0272] [Synthesis Example 1-3] Synthesis of Polymer 3 A 2L flask was charged with 7.8g of PAG monomer 3, 7.9g of ALG monomer 3, 5.8g of 4-hydroxy-3-methylstyrene, a monomer that provides a structure corresponding to repeating unit d, and 40g of THF as a solvent. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was carried out for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The resulting white solid was dried under reduced pressure at 60°C to obtain polymer 3. The composition of polymer 3 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0273] [Synthesis Example 1-4] Synthesis of Polymer 4 A 2L flask was charged with 9.8g of PAG monomer 4, 8.1g of ALG monomer 2, 4.4g of 3-hydroxystyrene, a monomer that provides a structure corresponding to repeating unit d, and 40g of THF as a solvent. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was carried out for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The resulting white solid was dried under reduced pressure at 60°C to obtain polymer 4. The composition of polymer 4 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0274] [Synthesis Example 1-5] Synthesis of Polymer 5 A 2L flask was charged with 9.1g of PAG monomer 5, 8.1g of ALG monomer 2, 5.2g of 4-hydroxy-3-methylstyrene (a monomer that provides a structure corresponding to repeating unit d), and 40g of THF as a solvent. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the mixture was heated to 60°C and reacted for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The resulting white solid was dried under reduced pressure at 60°C to obtain polymer 5. The composition of polymer 5 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0275] [Synthesis Example 1-6] Synthesis of Polymer 6 A 2L flask was charged with 12.2g of PAG monomer 6, 10.7g of ALG monomer 1, 4.4g of 3-hydroxystyrene, a monomer that provides a structure corresponding to repeating unit d, and 40g of THF as a solvent. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After heating to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was carried out for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The resulting white solid was dried under reduced pressure at 60°C to obtain polymer 6. The composition of polymer 6 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0276] [Synthesis Example 1-7] Synthesis of Polymer 7 A 2L flask was charged with 12.1g of PAG monomer 7, 8.1g of ALG monomer 2, 4.4g of 3-hydroxystyrene, a monomer that provides a structure corresponding to repeating unit d, and 40g of THF as a solvent. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was carried out for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The resulting white solid was dried under reduced pressure at 60°C to obtain polymer 7. The composition of polymer 7 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0277] [Synthesis Example 1-8] Synthesis of Polymer 8 A 2L flask was charged with 12.2g of PAG monomer 8, 8.1g of ALG monomer 2, 4.4g of 3-hydroxystyrene, a monomer that provides a structure corresponding to repeating unit d, and 40g of THF as a solvent. The reaction vessel was cooled to -70°C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2g of AIBN was added as a polymerization initiator, and the temperature was raised to 60°C and the reaction was carried out for 15 hours. This reaction solution was added to 1L of isopropyl alcohol, and the precipitated white solid was filtered off. The resulting white solid was dried under reduced pressure at 60°C to obtain polymer 8. The composition of polymer 8 was as follows: 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0278] [Synthesis Example 1-9] Synthesis of Comparative Polymer 1 Comparative polymer 1 was obtained in the same manner as in Synthesis Example 1-2, except that PAG monomer 2 was not used. The composition of comparative polymer 1 was 13 C-NMR and 1 Mw and Mw / Mn were confirmed by H-NMR and GPC, respectively. [ka]

[0279] [Examples 1 to 46, Comparative Examples 1 to 26] A solution of each component in the composition shown in Tables 1 to 5 dissolved in a solvent containing 50 ppm of Omnova surfactant Polyfox 636 was filtered through a 0.2 μm filter to prepare a positive resist material.

[0280] In Tables 1 to 5, the components are as follows: Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol) EL (Ethyl lactate) Quencher: Q-1~12 PAG:PAG-1 [ka]

[0281] [EUV exposure evaluation] Each resist material listed in Tables 1 to 5 was spin-coated onto a Si substrate with a 20 nm thick silicon-containing spin-on hard mask SHB-A940 (43 wt% silicon) and pre-baked at 105°C for 60 seconds on a hot plate to produce a 40 nm thick resist film. This was then exposed to light using an ASML EUV scanner NXE34000 (NA 0.33, σ 0.9 / 0.6, dipole illumination) to produce a 36 nm pitch LS pattern on the wafer. Post-exposure bake (PEB) was performed on a hot plate at the temperature listed in Table 1 for 60 seconds, and development was performed for 30 seconds in a 2.38 wt% TMAH aqueous solution to produce an 18 nm LS pattern. The resulting pattern was observed using a Hitachi High-Technologies Corporation critical dimension SEM (CG6300), and sensitivity and LWR were evaluated according to the following methods.

[0282] [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. The smaller this value, the higher the sensitivity.

[0283] [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.

[0284] [Table 1]

[0285] [Table 2] [Table 3]

[0286] [Table 4]

[0287] [Table 5]

[0288] The results in Tables 1 to 5 show that the resist compositions of Comparative Examples 1 to 26, which did not contain a sulfonium cation having the structure represented by formula (1) in either the polymer portion or the quencher portion, were evaluated as ×. On the other hand, the resist compositions of the present invention, which contained a sulfonium cation having the structure represented by formula (1) in at least one of the polymer portion and the quencher portion, exhibited good sensitivity and LWR performance, demonstrating that they are suitable as materials for EUV lithography. Furthermore, Examples 19 to 46, which contained a sulfonium cation having the structure represented by formula (1) in both the polymer portion and the quencher portion, were evaluated as ⊚, demonstrating particularly excellent performance.

[0289] This specification includes the following inventions.

[0290] [1]: A resist composition comprising a resin (A) containing a repeating unit represented by the following formula (a1) that generates an acid upon exposure, a photodegradable quencher represented by the following formula (b1), and an organic solvent, wherein M1 in the formula (a1) + , M2 in the formula (b1) + and at least one of the above is a sulfonium cation represented by the following formula (1): [ka] (In the formula, R a1 are each independently a hydrogen atom or a methyl group. a1is a single bond or an ester bond. a1 Rf is a single bond or a divalent organic group having 1 to 20 carbon atoms which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that Rf 1 ~Rf 4 At least one of M1 is a fluorine atom. + is a sulfonium cation. [ka] (In the formula, Rb is an organic group having 1 to 30 carbon atoms which may have a substituent. M2 + is a sulfonium cation. [ka] [In the formula, R 1 R is a fluorine atom, an iodine atom, or a perfluoroalkyl group. 2 , R 3 are each independently a fluorine atom or a perfluoroalkyl group. l is an integer of 0 to 3, m is an integer of 1 to 3, and n is an integer of 1 to 3. When l, m, and n are integers of 2 or more, R 1 , R 2 , R 3 may be the same or different, provided that the structure of formula (1) contains at least two fluorine atoms. 2 or R 3 is a fluorine atom, at least one fluorine atom is meta-substituted relative to the sulfur atom. [2]: The resist composition according to [1], wherein the photodecomposable quencher represented by the formula (b1) is represented by the following formula (b1-1): [ka] (In the formula, Rb' is an organic group having 1 to 22 carbon atoms which may have a substituent, and may contain an ester bond, an ether bond, an amide bond, a lactone ring, a sultone ring, an aromatic cyclic group, an aliphatic cyclic group, a hydroxyl group, an alkoxy group, a fluoroalkyl group, a nitro group, a cyano group, a trifluoromethoxy group, a carbonyl group, an amino group, an alkylamino group, a fluorine atom, a bromine atom, or an iodine atom. M2 + is a sulfonium cation. [3]: The resist composition according to [1] or [2], wherein the resin (A) further contains a repeating unit represented by the following formula (a2): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. 1 R is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and an ester bond, an ether bond, or a lactone ring. 11 is an acid labile group. [4]: The resist composition according to any one of [1] to [3], wherein the repeating unit represented by formula (a1) is represented by the following formula (a1-1): [ka] (In the formula, R a1 are each independently a hydrogen atom or a methyl group. a1 is a single bond or an ester bond. L1 is a single bond or a divalent linking group which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. L2 is a single bond or a divalent linking group which may contain an ester bond or an ether bond. Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that Rf 1 ~Rf 4 At least one of M1 is a fluorine atom. k is an integer of 0 to 4. +is a sulfonium cation. [5]: The resist composition according to any one of [1] to [4], wherein the repeating unit represented by the formula (a1) is represented by the following formula (a1-2): [ka] (R in the formula a1 are each independently a hydrogen atom or a methyl group. L1 is a single bond or a divalent linking group which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. L2 is a single bond or a divalent linking group which may contain an ester bond or an ether bond. Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that Rf 1 ~Rf 4 At least one of M1 is a fluorine atom. k is an integer of 0 to 4. + is a sulfonium cation. [6]: The resist composition according to any one of [1] to [5] above, wherein the anion moieties of the formula (a1) and the formula (b1) contain an iodine atom. [7]: M1 in the formula (a1) + and M2 in formula (b1) + and (c) a sulfonium cation represented by formula (1). [8]: The resist composition according to any one of [1] to [7], wherein in the formula (1), l is an integer of 1 to 3. [9]: The resist composition according to any one of [1] to [8], wherein the cation represented by the formula (1) contains an iodine atom.

[10] : A pattern forming method comprising the steps of: forming a resist film on a substrate using the resist composition according to any one of [1] to [9]; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

[11] : The pattern forming method according to

[10] , wherein the high-energy radiation used in the exposure step is i-rays, KrF excimer laser light, ArF excimer laser light, electron beams, or extreme ultraviolet rays having a wavelength of 3 to 15 nm.

[0291] 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 resist composition comprising a resin (A) containing a repeating unit represented by the following formula (a1) that generates an acid upon exposure, a photodegradable quencher represented by the following formula (b1), and an organic solvent, wherein M in the formula (a1) １ ＋ , M in the formula (b1) ２ ＋ and at least one of the above is a sulfonium cation represented by the following formula (1): 【Chemistry 1】 (In the formula, R ａ１ are each independently a hydrogen atom or a methyl group. １ ａ１ is a single bond or an ester bond. ２ ａ１ Rf is a single bond or a divalent organic group having 1 to 20 carbon atoms which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom, or an iodine atom. １ ~Rf ４ are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. １ ~Rf ４ At least one of M is a fluorine atom. １ ＋ is a sulfonium cation.) 【Chemistry 2】 (In the formula, Rb is an organic group having 1 to 30 carbon atoms which may have a substituent. M ２ ＋ is a sulfonium cation.) 【Transformation 3】 [In the formula, R １ is a fluorine atom, an iodine atom, or a perfluoroalkyl group. ２ , R ３ are each independently a fluorine atom or a perfluoroalkyl group. l is an integer of 0 to 3, m is an integer of 1 to 3, and n is an integer of 1 to 3. When l, m, and n are integers of 2 or more, R １ , R ２ , R ３ may be the same or different, provided that the structure of formula (1) contains at least two fluorine atoms. ２ or R ３ is a fluorine atom, at least one fluorine atom is substituted at the meta position relative to the sulfur atom.

2. 2. The resist composition according to claim 1, wherein the photodecomposable quencher represented by formula (b1) is represented by the following formula (b1-1): 【Chemistry 4】 (In the formula, Rb' is an organic group having 1 to 22 carbon atoms which may have a substituent, and may contain an ester bond, an ether bond, an amide bond, a lactone ring, a sultone ring, an aromatic cyclic group, an aliphatic cyclic group, a hydroxyl group, an alkoxy group, a fluoroalkyl group, a nitro group, a cyano group, a trifluoromethoxy group, a carbonyl group, an amino group, an alkylamino group, a fluorine atom, a bromine atom, or an iodine atom. M ２ ＋ is a sulfonium cation.)

3. 2. The resist composition according to claim 1, wherein the resin (A) further contains a repeating unit represented by the following formula (a2): 【Transformation 5】 (In the formula, R Ａ are each independently a hydrogen atom or a methyl group. １ R is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and an ester bond, an ether bond, or a lactone ring. １１ is an acid labile group.)

4. 2. The resist composition according to claim 1, wherein the repeating unit represented by formula (a1) is represented by the following formula (a1-1): 【Transformation 6】 (In the formula, R ａ１ are each independently a hydrogen atom or a methyl group. １ ａ１ is a single bond or an ester bond. １ L is a single bond or a divalent linking group which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom or an iodine atom. ２ Rf is a single bond or a divalent linking group which may contain an ester bond or an ether bond. １ ~Rf ４ are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. １ ~Rf ４ At least one of is a fluorine atom. k is an integer of 0 to 4. M １ ＋ is a sulfonium cation.)

5. 2. The resist composition according to claim 1, wherein the repeating unit represented by formula (a1) is represented by the following formula (a1-2): 【Transformation 7】 (In the formula R ａ１ are each independently a hydrogen atom or a methyl group. １ L is a single bond or a divalent linking group which may contain an ester bond, an ether bond, a lactone ring, an aromatic ring, a fluorine atom, a bromine atom or an iodine atom. ２ Rf is a single bond or a divalent linking group which may contain an ester bond or an ether bond. １ ~Rf ４ are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. １ ~Rf ４ At least one of is a fluorine atom. k is an integer of 0 to 4. M １ ＋ is a sulfonium cation.)

6. 2. The resist composition according to claim 1, wherein the anion moieties of the formulas (a1) and (b1) contain an iodine atom.

7. M in the formula (a1) １ ＋ and M in formula (b1) ２ ＋ 2. The resist composition according to claim 1, wherein both of are sulfonium cations represented by formula (1).

8. 2. The resist composition according to claim 1, wherein in formula (1), l is an integer of 1 to 3.

9. 2. The resist composition according to claim 1, wherein the cation represented by formula (1) contains an iodine atom.

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

11. 11. The pattern forming method according to claim 10, wherein the high-energy radiation used in the exposure step is i-rays, KrF excimer laser light, ArF excimer laser light, electron beams, or extreme ultraviolet rays having a wavelength of 3 to 15 nm.

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