Onium salt, chemically amplified positive resist composition, and resist pattern forming method

Abstract

The invention relates to an onium salt, a chemically amplified positive resist composition and a resist pattern forming method. The invention provides an onium salt capable of generating an acid with small diffusion, a chemically amplified positive resist composition containing the onium salt, and a resist pattern forming method using the resist composition. An onium salt represented by formula (1). # imgabs0 #

Description

Technical Field

[0001] The invention relates to an onium salt, a chemically amplified positive resist composition and a resist pattern forming method. Background Art

[0002] In recent years, with the high integration of integrated circuits, the formation of finer patterns is sought. The pattern processing below 0.2μm mainly uses chemically amplified resist compositions using acids as catalysts. At this time, the exposure source uses high-energy rays such as ultraviolet rays, far ultraviolet rays, and electron beams (EB), but EB lithography, which is especially used as an ultra-fine processing technology, has also become indispensable as a processing method for blank photomasks when making photomasks for semiconductor manufacturing. For such resist compositions used in optical lithography, there are positive types that dissolve the exposed part to form a pattern and negative types that leave the exposed part to form a pattern. It is easy for users to choose from them according to the form of the necessary resist pattern.

[0003] Generally speaking, EB drawing does not use a mask. If it is a positive type, a method of sequentially irradiating the micro-area EB to the parts other than the area to be retained of the resist film is adopted. If it is a negative type, a method of sequentially irradiating the micro-area EB to the area to be retained of the resist film is adopted. It is an operation to scan the entire area of ​​the processed surface divided into fine cells, so it is more time-consuming than batch exposure using a photomask. In order not to reduce the production capacity, a high-sensitivity resist film is required. In addition, the drawing time is long, so the initial drawing part and the later drawing part are prone to differences. The stability of the exposed part over time in a vacuum is an important performance requirement item. In addition, especially in the processing of blank photomasks for important purposes, some of them will have surface materials that are easy to affect the pattern shape of chemically amplified resist films such as chromium compounds such as chromium oxide that have been formed on the photomask substrate. In order to maintain high resolution and the shape after etching, it is not dependent on the type of substrate. Keeping the pattern outline of the resist film rectangular is also one of the important performance requirements.

[0004] The sensitivity of the resist film and the control of the pattern profile have been improved in various ways by utilizing the selection, combination, and processing conditions of the materials used in the resist composition. One of the improvements is the problem of acid diffusion, which has a significant impact on the resolution of the chemically amplified resist film. In photomask processing, it is hoped that the shape of the resist pattern obtained will not change depending on the time until post-exposure heating (PEB), but a major cause of time-dependent changes is the diffusion of acid generated by exposure. This acid diffusion problem is not limited to photomask processing, but also has a significant impact on sensitivity and resolution in general resist compositions, so there have been many discussions.

[0005] Patent Documents 1 and 2 describe examples of reducing roughness by suppressing acid diffusion by increasing the volume of acid generated from an acid generator. However, such acid generators are still insufficient in suppressing acid diffusion, and it is desired to develop an acid generator with a smaller diffusion.

[0006] In addition, Patent Document 3 describes an example of controlling acid diffusion by bonding sulfonic acid generated by exposure to a resin used in a resist composition. Such a method of inhibiting acid diffusion by bonding a repeating unit that generates acid by exposure to a base polymer is effective for obtaining a pattern with a small line edge roughness (LER). However, depending on the structure and introduction rate of such repeating units, there are also cases where the solubility of the base polymer to which the repeating unit that generates acid by exposure is bonded in an organic solvent becomes problematic.

[0007] There are many polymers with an aromatic skeleton having an acidic side chain, such as polyhydroxystyrene, which are useful as base polymers for KrF lithography resist compositions, but they show strong absorption for light with a wavelength of around 200 nm, so they are not used as base polymers for ArF lithography resist compositions. However, they are important materials for obtaining high etching resistance as resist compositions for EB lithography and EUV lithography, which are powerful technologies for forming patterns with smaller processing limits than ArF lithography.

[0008] As for the base polymer of positive EB photolithography resist composition and EUV photolithography resist composition, the acid generated by irradiating the photoacid generator with high-energy rays is mainly used as a catalyst to deprotect the acid-labile group (acid-decomposable protective group) of the acidic functional group of the phenol side chain of the shielding base polymer, thereby making it soluble in alkaline developer. The aforementioned acid-labile group mainly uses tertiary alkyl, tert-butoxycarbonyl, acetal group, etc. Here, although if a protective group with a relatively small activation energy required for deprotection such as acetal group is used, there is an advantage of obtaining a highly sensitive resist film, but if the diffusion of the generated acid is not fully suppressed, even the unexposed part in the resist film will undergo a deprotection reaction, which will cause LER degradation and a decrease in the in-plane uniformity (CDU) of the pattern line width.

[0009] In addition, Patent Documents 4 and 5 propose a scheme of a photoacid generator that generates a non-fluorinated aromatic sulfonic acid having a plurality of bulky alkyl substituents. Due to the plurality of alkyl substituents, the molecular weight of the generated acid increases, and the acid diffusion can be reduced. However, when forming a fine pattern, the inhibition of acid diffusion is still insufficient, and there is still room for improvement.

[0010] Furthermore, when forming fine patterns by EB lithography, the shape of the resist pattern becomes an inverse cone due to the influence of backscattering caused by the reflection of EB on the substrate. This is a problem. The inverse cone will induce the collapse of the resist pattern during development. In order to meet the requirements of further miniaturization, it is hoped to develop a photoacid generator that can solve the above-mentioned problems, correct the pattern shape, and also inhibit acid diffusion.

[0011] Prior art literature

[0012] Patent Literature

[0013] [Patent Document 1] Japanese Patent Application Publication No. 2009-053518

[0014] [Patent Document 2] Japanese Patent Application Publication No. 2010-100604

[0015] [Patent Document 3] Japanese Patent Application Publication No. 2011-22564

[0016] [Patent Document 4] Japanese Patent No. 6248882

[0017] [Patent Document 5] Japanese Patent Application Publication No. 2019-202974 Summary of the invention

[0018] [Problems to be solved by the invention]

[0019] In recent years, a resist composition having excellent line and space (LS), isolated line (IL), and isolated space (IS) as well as excellent hole pattern shape has been sought. Patent document 4 discloses an acid generator having a large volume of acid generated and suppressing acid diffusion. Although acid diffusion is suppressed to some extent, the shape of the pattern becomes an inverse cone when a fine pattern is formed, and there is a problem that the pattern collapses during development after alkali development.

[0020] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an onium salt capable of generating an acid with little diffusion, a chemically amplified positive resist composition containing the onium salt, and a resist pattern forming method using the resist composition.

[0021] [Methods for solving problems]

[0022] The inventors of the present application have made intensive researches to achieve the aforementioned objectives, and have found that when an onium salt of a fluorinated alkanesulfonic acid anion having an aromatic ring substituted with an alkyl group or a fluoroalkyl group and an iodine atom is introduced into a resist composition as an acid generator, the onium salt is concentrated in the upper layer of the resist film due to the effect of the alkyl group or the fluoroalkyl group, and a pattern with good resolution, small CDU and LER can be obtained due to the effect of correcting the pattern shape, and a pattern with good rectangularity can be obtained due to the moderate dissolution inhibition, thereby completing the present invention.

[0023] That is, the present invention provides the following onium salt, chemically amplified positive resist composition and resist pattern forming method.

[0024] 1. An onium salt represented by the following formula (1).

[0025] [Chemistry 1]

[0026]

[0027] In the formula, n1 is 0 or 1. n2 is 1, 2 or 3. n3 is 1, 2, 3 or 4. n4 is an integer of 0 to 4. However, when n1=0, 2≤n2+n3+n4≤5, and when n1=1, 2≤n2+n3+n4≤7. n5 is an integer of 0 to 4.

[0028] R alk R is an alkyl group having 6 to 18 carbon atoms or a fluorinated alkyl group having 4 to 18 carbon atoms. alk When it is an alkyl group having 6 to 18 carbon atoms, the alkyl group has at least one linear structure having 6 or more carbon atoms. alk When the fluorinated alkyl group has 4 to 18 carbon atoms, the fluorinated alkyl group has at least two groups selected from -CF2- and -CF3. In addition, a portion of the -CH2- of the aforementioned alkyl group and fluorinated alkyl group may be substituted by an ether bond or a carbonyl group, and the terminal or carbon-carbon bond thereof may contain a ring structure selected from a cyclopentane ring, a cyclohexane ring, an adamantane ring, a norbornyl ring and a benzene ring.

[0029] R 1 It is a halogen atom other than an iodine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom.

[0030] L A , L B and L C Each is independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a urethane bond.

[0031] X L It is a single bond or a alkylene group having 1 to 40 carbon atoms which may contain a hetero atom.

[0032] Q 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0033] Q 3 and Q 4 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0034] Z + It is an onium cation.

[0035] 2. The onium salt of 1. is represented by the following formula (1A),

[0036] [Chemistry 2]

[0037]

[0038] In the formula, n1~n5, R alk , R 1 , L A , L B , L C , X L , Q 1 , Q 2 and Z + Same as above.

[0039] 3. The onium salt as in 2. is represented by the following formula (1B),

[0040] [Chemistry 3]

[0041]

[0042] In the formula, n1~n5, R alk , R 1 , L A , L C , X L , Q 1 , Q 2 and Z + Same as above.

[0043] 4. The onium salt according to any one of 1. to 3., wherein Z + is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2),

[0044] [Chemistry 4]

[0045]

[0046] In the formula, R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. ct1 and R ct2 They may also bond to each other and to the sulfur atom to which they are bonded to form a ring.

[0047] 5. A photoacid generator, which is composed of the onium salt according to any one of 1. to 4.

[0048] 6. A chemically amplified positive resist composition comprising the photoacid generator of 5.

[0049] 7. The chemically amplified positive resist composition of 6. further comprises a base polymer, wherein the base polymer contains a polymer that is decomposed by an acid and has increased solubility in an alkaline developer.

[0050] 8. The chemically amplified positive resist composition of 7., wherein the polymer contains a repeating unit represented by the following formula (B1):

[0051] [Chemistry 5]

[0052]

[0053] In the formula, a1 is 0 or 1. a2 is an integer of 0 to 2. a3 is an integer satisfying 0≤a3≤5+2(a2)-a4. a4 is an integer of 1 to 3.

[0054] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0055] R 11 It is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom.

[0056] A 1 It is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, wherein -CH2- of the saturated alkylene group may be substituted by -O-.

[0057] 9. The chemically amplified positive resist composition of 7. or 8., wherein the polymer contains a repeating unit represented by the following formula (B2-1):

[0058] [Chemistry 6]

[0059]

[0060] In the formula, b1 is 0 or 1. b2 is an integer from 0 to 2. b3 is an integer satisfying 0≤b3≤5+2(b2)-b4. b4 is an integer from 1 to 3. b5 is 0 or 1.

[0061] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0062] R 12 It is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom.

[0063] A 2It is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, wherein -CH2- of the saturated alkylene group may be substituted by -O-.

[0064] When b4 is 1, X is an acid-labile group. When b4 is 2 or 3, X is independently a hydrogen atom or an acid-labile group, but at least one of them is an acid-labile group.

[0065] 10. The chemically amplified positive resist composition according to any one of 7. to 9., wherein the polymer contains a repeating unit represented by the following formula (B2-2):

[0066] [Chemistry 7]

[0067]

[0068] In the formula, c1 is an integer of 0 to 2. c2 is an integer of 0 to 2. c3 is an integer of 0 to 5. c4 is an integer of 0 to 2.

[0069] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0070] R 13 and R 14 Each independently represents a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom, R 13 With R 14 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring.

[0071] R 15 Each independently represents a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms.

[0072] R 16 Each independently represents a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom.

[0073] A 3 is a single bond, phenylene, naphthylene or *-C(=O)-OA 31 -.A 31 It is an aliphatic alkylene group having 1 to 20 carbon atoms which may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group. * represents an atomic bond to a carbon atom of the main chain.

[0074] 11. The chemically amplified positive resist composition according to any one of 7. to 10., wherein the polymer contains at least one selected from the group consisting of a repeating unit represented by the following formula (B3), a repeating unit represented by the following formula (B4), and a repeating unit represented by the following formula (B5),

[0075] [Chemistry 8]

[0076]

[0077] In the formula, d is an integer of 0 to 6. e is an integer of 0 to 4. f1 is 0 or 1. f2 is an integer of 0 to 2. f3 is an integer of 0 to 5.

[0078] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0079] R 17 and R 18 Each is independently a hydroxyl group, a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarboncarbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom.

[0080] R 19 It is a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbon oxy group having 1 to 20 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbon oxyalkyl group having 2 to 20 carbon atoms, a saturated hydrocarbon thialkyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, or a cyano group. When f2 is 1 or 2, it may also be a hydroxyl group.

[0081] A 4 It is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of -CH2- in the saturated alkylene group may be substituted by -O-.

[0082] 12. The chemically amplified positive resist composition according to any one of 7. to 11., wherein the polymer contains at least one selected from the group consisting of a repeating unit represented by the following formula (B6), a repeating unit represented by the following formula (B7), a repeating unit represented by the following formula (B8), and a repeating unit represented by the following formula (B9),

[0083] [Chemistry 9]

[0084]

[0085] In the formula, R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0086] X 1 It is a single bond or a phenylene group.

[0087] X 2 for* 1 -C(=O)-OX 21 -, * 1 -C(=O)-NH-X 21 -or* 1 -OX 21 -.X 21It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 1 Indicates and X 1 of atomic bonds.

[0088] X 3 Each independently represents a single bond, phenylene, naphthylene or * 2 -C(=O)-OX 31 -.X 31 It is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. 2 Represents the atomic bonds between the carbon atoms in the main chain.

[0089] X 4 Each is independently a single bond, * 3 -X 41 -C(=O)-O-,* 3 -C(=O)-NH-X 41 -or* 3 -OX 41 -.X 41 It is a carbon number 1-20 alkylene group which may contain a hetero atom. * 3 Indicates and X 3 of atomic bonds.

[0090] X 5 Each is independently a single bond, * 4 -X 51 -C(=O)-O-,* 4 -C(=O)-NH-X 51 -or* 4 -OX 51 -.X 51 It is a carbon number 1-20 alkylene group which may contain a hetero atom. * 4 Indicates and X 4 of atomic bonds.

[0091] X 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, * 2 -C(=O)-OX 61 -, * 2 -C(=O)-N(H)-X 61 -or* 2 -OX 61 -.X 61 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group. 2Represents the atomic bonds between the carbon atoms in the main chain.

[0092] R 21 and R 22 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 21 and R 22 They may also bond to each other and to the sulfur atom to which they are bonded to form a ring.

[0093] L 1 It is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond.

[0094] R 1 and Rf 2 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0095] R 3 and Rf 4 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0096] R 5 and Rf 6 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 5 and Rf 6 At the same time it is a hydrogen atom.

[0097] M - It is a non-nucleophilic relative ion.

[0098] A + It is an onium cation.

[0099] g1 and g2 are each independently an integer of 0-3.

[0100] 13. The chemically amplified positive resist composition according to any one of 7. to 12. further contains an organic solvent.

[0101] 14. The chemically amplified positive resist composition according to any one of 7. to 13. further comprises a polymer containing fluorine atoms, wherein the polymer containing fluorine atoms comprises at least one selected from the group consisting of a repeating unit represented by the following formula (D1), a repeating unit represented by the following formula (D2), a repeating unit represented by the following formula (D3), and a repeating unit represented by the following formula (D4), and may also comprise at least one selected from the group consisting of a repeating unit represented by the following formula (D5) and a repeating unit represented by the following formula (D6),

[0102] [Chemistry 10]

[0103]

[0104] In the formula, j1 is an integer of 1 to 3. j2 is an integer satisfying 0≤j2≤5+2(j3)-j1. j3 is 0 or 1. k is an integer of 1 to 3.

[0105] R B Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0106] R C Each is independently a hydrogen atom or a methyl group.

[0107] R 101 , R 102 , R 104 and R 105 Each is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms.

[0108] R 103 , R 106 , R 107 and R 108 are each independently a hydrogen atom, a hydrocarbon group having 1 to 15 carbon atoms, a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group, and R 103 , R 106 , R 107 and R 108 In the case of a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between carbon-carbon bonds.

[0109] R 109 It is a hydrogen atom or a linear or branched hydrocarbon group having 1 to 5 carbon atoms in which a hetero atom-containing group may be inserted between carbon-carbon bonds.

[0110] R 110 It is a linear or branched hydrocarbon group having 1 to 5 carbon atoms, which may contain a hetero atom-containing group inserted between carbon-carbon bonds.

[0111] R 111 It is a saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted by a fluorine atom, and a part of the -CH2- of the saturated hydrocarbon group may be substituted by an ester bond or an ether bond.

[0112] Z 1 It is a (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms.

[0113] Z 2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond with a carbon atom of the main chain.

[0114] Z 3 is a single bond, -O-, *-C(=O)-OZ 31 -Z 32 - or *-C(=O)-NH-Z31 -Z 32 -.Z 31 Z is a single bond or a saturated alkylene group having 1 to 10 carbon atoms. 32 It is a single bond, ester bond, ether bond or sulfonamide bond. * indicates an atomic bond between the carbon atoms of the main chain.

[0115] 15. The chemically amplified positive resist composition according to any one of 7. to 14. further comprises a quencher.

[0116] 16. The chemically amplified positive resist composition according to any one of 7. to 15. further comprises a photoacid generator other than the photoacid generator according to 5.

[0117] 17. A method for forming a resist pattern, comprising the following steps:

[0118] A resist film is formed on a substrate using the chemically amplified positive resist composition as described in any one of 7. to 16., the resist film is exposed using high-energy rays, and the exposed resist film is developed using an alkaline developer to obtain a resist pattern.

[0119] 18. The resist pattern forming method according to 17., wherein the high-energy ray is extreme ultraviolet ray or electron beam.

[0120] 19. The resist pattern forming method according to 17. or 18., wherein the outermost surface of the substrate is made of a material containing chromium.

[0121] 20. The method for forming a resist pattern according to any one of 17. to 19., wherein the substrate is a blank photomask.

[0122] [Effects of the Invention]

[0123] The chemically amplified positive resist composition containing the onium salt of the present invention as a photoacid generator has extremely high resolution in microfabrication technology, especially EB lithography and EUV lithography, and can provide a pattern with a small LER. In addition, due to its moderate dissolution barrier, it can provide a pattern with good rectangularity, so it is suitable as a chemically amplified positive photoresist material. BRIEF DESCRIPTION OF THE DRAWINGS

[0124] Figure 1 is the nuclear magnetic resonance spectrum of the onium salt PAG-1 synthesized in Example 1-1 ( 1 H-NMR / DMSO-d6).

[0125] Figure 2 is the nuclear magnetic resonance spectrum of the onium salt PAG-2 synthesized in Example 1-2 ( 1 H-NMR / DMSO-d6).

[0126] Figure 3 is the nuclear magnetic resonance spectrum of the onium salt PAG-3 synthesized in Example 1-3 ( 1 H-NMR / DMSO-d6). DETAILED DESCRIPTION

[0127] The present invention is described in detail below. In addition, in the following description, depending on the structure represented by the chemical formula, there may be an asymmetric carbon and mirror image isomers and non-mirror image isomers. In this case, these isomers are represented by one formula. These isomers can be used alone or in the form of a mixture of two or more.

[0128] [Onium salt]

[0129] The onium salt of the present invention is represented by the following formula (1).

[0130] [Chemistry 11]

[0131]

[0132] In formula (1), n1 is 0 or 1. When n1=0, it represents a benzene ring, and when n1=1, it represents a naphthalene ring. However, in view of solvent solubility, n1 is preferably a benzene ring of 0. n2 is 1, 2 or 3, and 1 or 2 is preferred. n3 is 1, 2, 3 or 4, and 1, 2 or 3 is preferred in view of solvent solubility. n4 is an integer of 0 to 4, and 0 or 1 is preferred. However, when n1=0, 2≤n2+n3+n4≤5. When n1=1, 2≤n2+n3+n4≤7. n5 is an integer of 0 to 4, and an integer of 0 to 3 is preferred, and 1 is more preferred.

[0133] In formula (1), R alk It is an alkyl group having 6 to 18 carbon atoms or a fluorinated alkyl group having 4 to 18 carbon atoms.

[0134] R alk When it is an alkyl group having 6 to 18 carbon atoms, the alkyl group has at least one linear structure having 6 or more carbon atoms. alk Specific examples of the alkyl group having 6 to 18 carbon atoms represented by R include 1-hexyl, 1-heptyl, 1-octyl, 1-nonyl, 1-decyl, 1-undecyl, 1-dodecyl, 1-tridecyl, 1-tetradecyl, 1-hexadecyl, 1-octadecyl, octan-2-yl, decan-2-yl, decan-4-yl, octadec-8-yl, 7,7-dimethyloctyl, 7,7-diethylnonyl, 4-butyldodecyl, etc. In addition, a part of -CH2- in the aforementioned alkyl group may be substituted by an ether bond or a carbonyl group, and in terms of a partial structure, it may have a ring structure at the end or between carbon-carbon bonds, such as a cyclopentane ring, a cyclohexane ring, an adamantane ring, a norbornane ring, or a benzene ring. alk Preferably, it is a straight-chain alkyl or a straight-chain ethylene glycol dimethyl ether (glyme) chain. Also, when n2 is 2 or 3, each Ralk Can be the same or different.

[0135] R alk When it is a fluorinated alkyl group having 4 to 18 carbon atoms, the fluorinated alkyl group has at least two groups selected from -CF2- and -CF3. alk Specific examples of the fluorinated alkyl group having 4 to 18 carbon atoms represented by the fluorinated alkyl group include 1-butyl, 1-pentyl, 1-hexyl, 1-heptyl, 1-octyl, 1-nonyl, 1-decyl, 1-undecyl, 1-dodecyl, 1-tridecyl, 1-tetradecyl, 1-hexadecyl, 1-octadecyl, octan-2-yl, decane-2-yl, decane-4-yl, octadecane-8-yl, 7,7-dimethyloctyl, 7,7-diethylnonyl, 4-butyldodecyl, etc., in which a part or all of the hydrogen atoms are substituted with fluorine atoms. In addition, a part of -CH2- of the above-mentioned fluorinated alkyl group may be substituted with an ether bond or a carbonyl group, and in terms of a partial structure, the terminal or between carbon-carbon bonds may have a ring structure, such as a cyclopentane ring, a cyclohexane ring, an adamantane ring, a norbornyl ring, or a benzene ring.

[0136] R alk The following are preferred, but not limited to these. In the following formula, the chain line represents the bond hand.

[0137] [Chemistry 12]

[0138]

[0139] In formula (1), R 1 It is a halogen atom other than an iodine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom, and a fluorine atom is preferred.

[0140] R 1 The hydrocarbon group represented by may be saturated or unsaturated, and specific examples thereof include branched alkyl groups having 3 to 20 carbon atoms, such as isopropyl, sec-butyl, tert-butyl, tert-pentyl, 2-ethylhexyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6] cycloaliphatic hydrocarbon groups having 3 to 20 carbon atoms, such as decyl and adamantyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, anthracenyl; and groups obtained by combining them, but not limited to these. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, it may also contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0141] When n4 is 2 or more, two R 1 They may also be bonded to each other and form a ring together with the carbon atoms to which they are bonded. In this case, the formed ring is, for example, a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, etc. In addition, a part or all of the hydrogen atoms in the aforementioned ring may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- in the aforementioned ring may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. As a result, a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. may be contained.

[0142] In formula (1), L A , L B and L C Each is independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a urethane bond. A and L B It is preferably a single bond, an ether bond, an ester bond or a sulfonate bond, and more preferably a single bond, an ether bond or an ester bond. C It is preferably a single bond, an ether bond or an ester bond, and more preferably a single bond or an ether bond.

[0143] In formula (1), X L A alkylene group having 1 to 40 carbon atoms and a single bond or optionally containing a hetero atom. The alkylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl and cyclic saturated alkylene groups. Specific examples of the hetero atom include oxygen, nitrogen, and sulfur atoms.

[0144] X L Specific examples of the alkylene group having 1 to 40 carbon atoms which may contain a hetero atom represented by are listed below, but are not limited to these. A and L B of atomic bonds.

[0145] [Chemistry 13]

[0146]

[0147] [Chemistry 14]

[0148]

[0149] [Chemistry 15]

[0150]

[0151] [Chemistry 16]

[0152]

[0153] Among these, X L -0~X L -22 and X L -47~X L -58 is better.

[0154] In formula (1), Q 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group is preferably a trifluoromethyl group.

[0155] In formula (1), Q 3 and Q 4 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. The fluorinated saturated hydrocarbon group is preferably a trifluoromethyl group.

[0156] In formula (1), -[C(Q 1 )(Q 2 )] n5 -C(Q 3 )(Q 4 )-SO3 - The specific examples of the partial structure represented by are preferably those shown below, but are not limited to these. In the following formula, * represents and L B of atomic bonds.

[0157] [Chemistry 17]

[0158]

[0159] Among these, Acid-1 to Acid-7 are preferred, and Acid-1 to Acid-3, Acid-6 and Acid-7 are more preferred.

[0160] The onium salt represented by the formula (1) is preferably represented by the following formula (1A).

[0161] [Chemistry 18]

[0162]

[0163] In the formula, n1~n5, R alk , R 1 , L A , L B , L C , X L , Q 1 , Q 2 and Z + The onium salt represented by the formula (1A) is preferably represented by the following formula (1B).

[0164] [Chemistry 19]

[0165]

[0166] In the formula, n1~n5, R alk , R 1 , L A , L C , X L , Q 1 , Q 2 and Z + As described above, particularly preferred examples of the anion of the onium salt represented by formula (1) include the following, but are not limited thereto.

[0167] [Chemistry 20]

[0168]

[0169] [Chemistry 21]

[0170]

[0171] [Chemistry 22]

[0172]

[0173] [Chemistry 23]

[0174]

[0175] [Chemistry 24]

[0176]

[0177] [Chemistry 25]

[0178]

[0179] [Chemistry 26]

[0180]

[0181] [Chemistry 27]

[0182]

[0183] [Chemistry 28]

[0184]

[0185] [Chemistry 29]

[0186]

[0187] [Chemistry 30]

[0188]

[0189] [Chemistry 31]

[0190]

[0191] [Chemistry 32]

[0192]

[0193] [Chemistry 33]

[0194]

[0195] [Chemistry 34]

[0196]

[0197] [Chemistry 35]

[0198]

[0199] [Chemistry 36]

[0200]

[0201] [Chemistry 37]

[0202]

[0203] [Chemistry 38]

[0204]

[0205] [Chemistry 39]

[0206]

[0207] [Chemistry 40]

[0208]

[0209] [Chemistry 41]

[0210]

[0211] [Chemistry 42]

[0212]

[0213] [Chemistry 43]

[0214]

[0215] [Chemistry 44]

[0216]

[0217] [Chemistry 45]

[0218]

[0219] [Chemistry 46]

[0220]

[0221] [Chemistry 47]

[0222]

[0223] [Chemistry 48]

[0224]

[0225] [Chemistry 49]

[0226]

[0227] [Chemistry 50]

[0228]

[0229] [Chemistry 51]

[0230]

[0231] [Chemistry 52]

[0232]

[0233] [Chemistry 53]

[0234]

[0235] [Chemistry 54]

[0236]

[0237] [Chemistry 55]

[0238]

[0239] [Chemistry 56]

[0240]

[0241] [Chemistry 57]

[0242]

[0243] [Chemistry 58]

[0244]

[0245] [Chemistry 59]

[0246]

[0247] [Chemistry 60]

[0248]

[0249] [Chemistry 61]

[0250]

[0251] [Chemistry 62]

[0252]

[0253] [Chemistry 63]

[0254]

[0255] [Chemistry 64]

[0256]

[0257] [Chemistry 65]

[0258]

[0259] [Chemistry 66]

[0260]

[0261] [Chemistry 67]

[0262]

[0263] [Chemistry 68]

[0264]

[0265] [Chemistry 69]

[0266]

[0267] [Chemistry 70]

[0268]

[0269] [Chemistry 71]

[0270]

[0271] [Chemistry 72]

[0272]

[0273] [Chemistry 73]

[0274]

[0275] [Chemistry 74]

[0276]

[0277] In formula (1), Z + The onium cation is preferably a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2).

[0278] [Chemistry 75]

[0279]

[0280] In formula (cation-1) and (cation-2), R ct1 ~R ct5 Each is independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom.

[0281] R ct1 ~R ct5 Examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0282] R ct1 ~R ct5The hydrocarbon group represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 30 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 30 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 30 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them, among which aryl groups are preferred. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxyl group, a cyano group, a nitro group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0283] Again, R ct1 and R ct2 They may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. In this case, the structure of the ring may be represented by the following formula.

[0284] [Chemistry 76]

[0285]

[0286] In the formula, the chain line represents and R ct3 of atomic bonds.

[0287] The sulfonium cation represented by the formula (cation-1) may be exemplified by the following, but is not limited thereto.

[0288] [Chemistry 77]

[0289]

[0290] [Chemistry 78]

[0291]

[0292] [Chemistry 79]

[0293]

[0294] [Chemistry 80]

[0295]

[0296] [Chemistry 81]

[0297]

[0298] [Chemistry 82]

[0299]

[0300] [Chemistry 83]

[0301]

[0302] [Chemistry 84]

[0303]

[0304] [Chemistry 85]

[0305]

[0306] [Chemistry 86]

[0307]

[0308] [Chemistry 87]

[0309]

[0310] [Chemistry 88]

[0311]

[0312] [Chemistry 89]

[0313]

[0314] [Chemistry 90]

[0315]

[0316] [Chemistry 91]

[0317]

[0318] [Chemistry 92]

[0319]

[0320] [Chemistry 93]

[0321]

[0322] [Chemistry 94]

[0323]

[0324] [Chemistry 95]

[0325]

[0326] [Chemistry 96]

[0327]

[0328] [Chemistry 97]

[0329]

[0330] [Chemistry 98]

[0331]

[0332] [Chemistry 99]

[0333]

[0334] [Chemical 100]

[0335]

[0336] [Chemistry 101]

[0337]

[0338] [Chemistry 102]

[0339]

[0340] [Chemistry 103]

[0341]

[0342] Examples of the iodonium cation represented by the formula (cation-2) include those shown below, but are not limited thereto.

[0343] [Chemistry 104]

[0344]

[0345] [Chemistry 105]

[0346]

[0347] Specific examples of the onium salt of the present invention include any combination of the above-mentioned anions and cations.

[0348] The onium salt (1) of the present invention can be synthesized by a known method. For example, a method for producing an onium salt represented by the following formula (PAG-1-ex) will be described.

[0349] [Chemistry 106]

[0350]

[0351] In the formula, n1~n5, R alk , R 1 , L A , X L , Q 1 ~Q 4 and Z + Same as above. Hal is a chlorine atom, a bromine atom or an iodine atom. X It is a group that forms a primary or secondary ester with the adjacent -CO2-. + Is a relative cation. - is the relative anion.

[0352] The first step is to obtain the intermediate In-1-ex by reacting a commercially available product or a phenol compound (SM-1) that can be synthesized by a known synthesis method with a haloalkyl compound (SM-2). The reaction can be carried out using a known organic synthesis method. Specifically, the raw material SM-1 is dissolved in a non-protonic polar solvent such as acetone, acetonitrile, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and a base is added. The raw material SM-2 is added dropwise and reacted. The base used, such as hydroxides such as sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide, carbonates such as potassium carbonate and sodium bicarbonate, etc., these bases can be used alone or in combination of two or more. It can also be heated as needed. The reaction temperature is carried out at room temperature to about the boiling point of the solvent used, but if it is carried out under heating conditions, the reaction will proceed smoothly, which is more ideal. In addition, the reaction can be accelerated by adding an alkali metal iodide as a catalyst. For example, sodium iodide and potassium iodide. The reaction time is about 4 to 12 hours, which is good in terms of yield, when the reaction is completed by tracking the reaction with silica gel thin layer chromatography (TLC). Afterwards, the reaction is stopped with water, the target product is extracted from the reaction mixture, and a conventional aqueous work-up is performed to obtain the intermediate In-1-ex. The obtained intermediate In-1-ex can be purified by conventional methods such as chromatography and recrystallization, if necessary.

[0353] The second step is to convert the -CO2-R xThe step of hydrolyzing the primary or secondary ester bond with a base to obtain the intermediate In-2-ex. The reaction can be carried out using a known organic synthesis method. Specifically, the intermediate In-1-ex is suspended in an ether solvent such as water or tetrahydrofuran (THF), and a base is added and hydrolyzed. The base used is preferably an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. The reaction temperature is from room temperature to about the boiling point of the solvent used, but if it is carried out under heating conditions, the reaction will proceed smoothly, so it is ideal. The reaction time is ideal in terms of yield if the reaction is tracked by TLC and the reaction is completed, but it is usually about 4 to 12 hours. Afterwards, the reaction is carried out using dilute hydrochloric acid, etc., and the target product is extracted from the reaction mixture at a point where the pH becomes slightly acidic, and a conventional aqueous work-up is performed to obtain the intermediate In-2-ex. The intermediate In-2-ex obtained can be purified by conventional methods such as chromatography and recrystallization if necessary.

[0354] The third step is a step of obtaining the intermediate In-3-ex by reacting the intermediate In-2-ex with the raw material SM-3. When the ester bond is directly formed by the carboxyl group of the intermediate In-2-ex and the hydroxyl group of the raw material SM-3, various condensing agents can be used. The condensing agent used, for example, N, N'-dicyclohexylcarbodiimide, N, N'-diisopropylcarbodiimide, 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide, hydrochloric acid 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, etc., but considering the ease of removal of the urea compound generated as a by-product after the reaction, hydrochloric acid 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide is preferably used. The reaction is carried out by dissolving the intermediate In-2-ex and the raw material SM-3 in a halogen-based solvent such as dichloromethane and adding a condensing agent. If 4-dimethylaminopyridine (DMAP) is added as a catalyst, the reaction rate can be increased. The reaction time is generally about 12 to 24 hours, which is good in terms of yield if the reaction is tracked by TLC and the reaction is completed. After the reaction is stopped, the by-product urea compound is removed by filtration or washing as needed, and the reaction solution is subjected to a conventional aqueous work-up to obtain the intermediate In-3-ex. In addition, the intermediate In-2-ex can be prepared from the acid chloride using oxalyl chloride or thionyl chloride, and then reacted with the raw material SM-3 to obtain the intermediate In-3-ex. It is preferred to use a base such as triethylamine, diisopropylethylamine, pyridine, and 2,6-lutidine during the reaction. In addition, in order to accelerate the reaction, it is preferred to add 4-dimethylaminopyridine (DMAP) as a catalyst. The intermediate In-3-ex obtained can be purified by conventional methods such as chromatography and recrystallization if necessary.

[0355] The fourth step is to make the intermediate In-3-ex and Z + X -A step of obtaining an onium salt PAG-1-ex by salt exchange with an onium salt represented by X. - When the reaction is carried out in the form of chloride ion, bromide ion, iodide ion or methylsulfate anion, the exchange reaction is easy to proceed quantitatively and is more desirable. The progress of the reaction is more desirable in terms of yield if confirmed by TLC. The onium salt PAG-1-ex can be obtained by performing a conventional aqueous work-up on the reaction mixture. If necessary, it can be purified by conventional methods such as chromatography and recrystallization.

[0356] In the above scheme, the ion exchange in the fourth step can be easily performed by a known method, for example, refer to Japanese Patent Application Laid-Open No. 2007-145797.

[0357] The above-mentioned production method is merely an example, and the production method of the onium salt of the present invention is not limited thereto.

[0358] The onium salt represented by formula (1) is characterized by containing an alkyl or fluoroalkyl group and an iodine atom on the aromatic ring of the anion. The alkyl or fluoroalkyl group on the aromatic ring acts as a hydrophobic group, so it is believed that the onium salt will be concentrated on the surface layer in the resist film. In particular, in alkali-developed positive EB lithography, due to the backscattering between the EB and the substrate, the pattern shape becomes an inverse cone, which causes the collapse of the pattern after development, which becomes a problem. However, by using the onium salt of the present invention, the deprotection reaction of the base polymer is also effectively carried out in the upper layer of the pattern, so it can be corrected into a rectangular pattern. In addition, the iodine atom on the aromatic ring also improves the sensitivity during EB lithography, and also has moderate dissolution inhibition. Due to these multiplying effects, when the onium salt of the present invention is used, a pattern with good resolution, high contrast and small CDU and LER can be obtained, and it is believed that due to the moderate dissolution inhibition, a pattern with good rectangularity can be obtained. In addition, the onium salt of the present invention is easy to manufacture and handle because it has sufficient fat solubility.

[0359] The onium salt of the present invention is suitable for use as a photoacid generator.

[0360] [Chemically amplified positive resist composition]

[0361] [(A) Photoacid generator]

[0362] The chemically amplified positive resist composition of the present invention contains a photoacid generator composed of an onium salt represented by the formula (1) as the component (A) as an essential component.

[0363] In the chemically amplified positive resist composition of the present invention, the content of the (A) photoacid generator is preferably 0.1 to 20 parts by mass, and more preferably 1 to 10 parts by mass, relative to 80 parts by mass of the (B) base polymer described later. If the content of the photoacid generator is within the above range, an acid necessary for deprotection of the acid-labile group will be generated, and a good pattern shape can be obtained. In addition, the storage stability is also good. The (A) photoacid generator can be used alone or in combination of two or more.

[0364] [(B) Base polymer]

[0365] The resist composition of the present invention contains, as the component (B), a base polymer containing a polymer that is decomposed by an acid and has increased solubility in an alkaline developer.

[0366] The aforementioned polymer is preferably a polymer containing a repeating unit represented by the following formula (B1) (hereinafter also referred to as repeating unit B1).

[0367] [Chemistry 107]

[0368]

[0369] In formula (B1), a1 is 0 or 1. a2 is an integer of 0 to 2, and when 0, it represents a benzene skeleton, when 1, it represents a naphthalene skeleton, and when 2, it represents an anthracene skeleton. a3 is an integer satisfying 0≤a3≤5+2(a2)-a4. a4 is an integer of 1 to 3. When a2 is 0, it is preferred that a3 is an integer of 0 to 3 and a4 is an integer of 1 to 3. When a2 is 1 or 2, it is preferred that a3 is an integer of 0 to 4 and a4 is an integer of 1 to 3.

[0370] In formula (B1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0371] In formula (B1), R 11 It is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom. The saturated hydrocarbon group, the saturated hydrocarbon carbonyloxy group, and the saturated hydrocarbon group of the saturated hydrocarbonoxy group may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, hexyl, and their structural isomers; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining them. If the number of carbon atoms is below the upper limit, the solubility in the alkaline developer is good. When a3 is 2 or more, each R 11 They may be the same as or different from each other.

[0372] In formula (B1), A 1is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of -CH2- in the saturated alkylene group may be substituted by -O-. The saturated alkylene group may be linear, branched or cyclic, and specific examples thereof include alkylene groups having 1 to 10 carbon atoms such as methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, and their structural isomers; cyclic saturated alkylene groups having 3 to 10 carbon atoms such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining them. When the saturated alkylene group contains an ether bond, when a1 in formula (B1) is 1, it may be intercalated at any position other than between the carbon atom at the α position and the carbon atom at the β position relative to the ester oxygen atom. When a1 is 0, the atom bonded to the main chain becomes an etheric oxygen atom, and the second ether bond may be interposed at any position other than between the carbon atom at the α position and the carbon atom at the β position relative to the etheric oxygen atom. It is also preferred that the carbon number of the saturated alkylene group is 10 or less, since sufficient solubility in an alkaline developer can be obtained.

[0373] a1 is 0 and A 1 When it is a single bond, the aromatic ring is directly bonded to the main chain of the polymer (that is, there is no connecting group (-C(=O)-OA 1 -)), the repeating unit B1 preferably includes units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, etc. Specifically, the following are mentioned, but they are not limited to these.

[0374] [Chemistry 108]

[0375]

[0376] [Chemistry 109]

[0377]

[0378] [Chemistry 110]

[0379]

[0380] a1 is 1 (i.e., having -C(=O)-OA 1 - as a linking group), the following are the ideal examples of repeating unit B1, but they are not limited to these. A Same as above.

[0381] [Chemistry 111]

[0382]

[0383] [Chemistry 112]

[0384]

[0385] [Chemistry 113]

[0386]

[0387] [Chemistry 114]

[0388]

[0389] The content of repeating unit B1 is preferably 15 to 90 mol % of all repeating units constituting the aforementioned polymer, and more preferably 15 to 80 mol %. However, when at least one of the repeating units represented by formula (B3) and the repeating units represented by formula (B4) that provide high etching resistance to the polymer described later is contained and the unit has a phenolic hydroxyl group as a substituent, it is preferable to also add the ratio thereof and it is preferable to be within the aforementioned range. Repeating unit B1 can be used alone or in combination of two or more.

[0390] In order to give the exposed part of the positive resist composition the property of being soluble in alkaline developer, the above-mentioned polymer preferably contains a repeating unit having an acidic functional group protected by an acid-labile group, that is, a repeating unit protected by an acid-labile group and becoming alkali-soluble due to the action of acid (hereinafter also referred to as repeating unit B2).

[0391] The most desirable repeating unit B2 is, for example, one represented by the following formula (B2-1) (hereinafter also referred to as repeating unit B2-1).

[0392] [Chemistry 115]

[0393]

[0394] In formula (B2-1), b1 is 0 or 1. b2 is an integer of 0 to 2, and when 0, it represents a benzene skeleton, when 1, it represents a naphthalene skeleton, and when 2, it represents an anthracene skeleton. b3 is an integer satisfying 0≤b3≤5+2(b2)-b4. b4 is an integer of 1 to 3. b5 is 0 or 1. When b2 is 0, it is preferred that b3 is an integer of 0 to 3 and b4 is an integer of 1 to 3. When b2 is 1 or 2, it is preferred that b3 is an integer of 0 to 4 and b4 is an integer of 1 to 3.

[0395] In formula (B2-1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0396] In formula (B2-1), R 12It is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom. The saturated hydrocarbon group, the saturated hydrocarbon carbonyloxy group, and the saturated hydrocarbon group of the saturated hydrocarbonoxy group may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, hexyl, and their structural isomers; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining them. If the number of carbon atoms is below the upper limit, the solubility in the alkaline developer is good. When b3 is 2 or more, each R 12 They may be the same as or different from each other.

[0397] Regarding the content of repeating units B3 to B5, in order to improve the etching resistance, it is preferred that the content is 5 mol% or more of all repeating units constituting the aforementioned polymer. In addition, the content of repeating units B3 to B5 is preferably 25 mol% or less of all repeating units constituting the aforementioned polymer, and 20 mol% or less is more preferred. When there is no functional group or the functional group is other than hydroxyl, the introduction amount is 25 mol% or less, so there is no risk of developing defects, so it is ideal. Repeating units B3 to B5 can be used alone or in combination of two or more.

[0398] In formula (B2-1), A 2 is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of -CH2- in the saturated alkylene group may be substituted by -O-. The saturated alkylene group may be straight chain, branched or cyclic, and specific examples thereof include alkylene groups having 1 to 10 carbon atoms such as methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, and their structural isomers; cyclic saturated alkylene groups having 3 to 10 carbon atoms such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining them. When the saturated alkylene group contains an ether bond, when b1 in formula (B2-1) is 1, it may be intercalated at any position other than between the carbon atom at the α position and the carbon atom at the β position relative to the ester oxygen atom. When b1 is 0, the atom bonded to the main chain becomes an etheric oxygen atom, and the second ether bond may be interposed at any position other than between the carbon atom at the α position and the carbon atom at the β position relative to the etheric oxygen atom. It is also preferred that the carbon number of the saturated alkylene group is 10 or less, since sufficient solubility in an alkaline developer can be obtained.

[0399] In formula (B2-1), when b4 is 1, X is an acid-labile group. When b4 is 2 or 3, X is independently a hydrogen atom or an acid-labile group, but at least one of them is an acid-labile group. That is, in repeating unit B2-1, at least one of the phenolic hydroxyl groups bonded to the aromatic ring is protected by an acid-labile group, or the carboxyl group bonded to the aromatic ring is protected by an acid-labile group. The aforementioned acid-labile group can be any acid-labile group that is used in most known chemically amplified positive resist compositions and that gives an acidic group due to acid detachment, and can be used without special limitation.

[0400] The acid-labile group is, for example, a saturated tertiary hydrocarbon group. The saturated tertiary hydrocarbon group preferably has 4 to 18 carbon atoms in order to obtain a monomer for polymerization by distillation.

[0401] The saturated hydrocarbon group bonded to the tertiary carbon atom of the aforementioned saturated tertiary hydrocarbon group preferably has 1 to 15 carbon atoms. The aforementioned saturated hydrocarbon group having 1 to 15 carbon atoms may be straight chain, branched, or cyclic, and may contain an ether bond, a carbonyl group, or other oxygen-containing functional group between carbon-carbon bonds. Furthermore, the saturated hydrocarbon groups bonded to the tertiary carbon atoms may be bonded to each other and may form a ring together with the tertiary carbon atoms to which they are bonded.

[0402] The aforementioned alkyl substituents, for example, methyl, ethyl, propyl, adamantyl, norbornyl, tetrahydrofuran-2-yl, 7-oxanorbornan-2-yl, cyclopentyl, 2-tetrahydrofuranyl, tricyclo[5.2.1.0 2,6 ]decyl, 8-ethyl-8-tricyclo[5.2.1.0 2 ,6 ]decyl, 3-methyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 ]Dodecayl, tetracyclic [4.4.0.1 2,5 .1 7,10 ] dodecanyl, 3-oxo-1-cyclohexyl, etc.

[0403] The aforementioned saturated tertiary hydrocarbon groups, for example, tert-butyl, tert-amyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1,2-trimethylpropyl, 1-adamantyl-1-methylethyl, 1-methyl-1-(2-norbornyl)ethyl, 1-methyl-1-(tetrahydrofuran-2-yl)ethyl, 1-methyl-1-(7-oxanorbornan-2-yl)ethyl, 1-methylcyclopentyl, 1-ethyl 1-propylcyclopentyl, 1-cyclopentylcyclopentyl, 1-cyclohexylcyclopentyl, 1-(2-tetrahydrofuranyl)cyclopentyl, 1-(7-oxanorbornan-2-yl)cyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl, 1-cyclopentylcyclohexyl, 1-cyclohexylcyclohexyl, 2-methyl-2-norbornyl, 2-ethyl-2-norbornyl, 8-methyl-8-tricyclo[5.2.1.0 2,6]decyl, 8-ethyl-8-tricyclo[5.2.1.0 2,6 ]decyl, 3-methyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 ] dodecyl, 3-ethyl-3-tetracyclo[4.4.0.1 2, 5 .1 7,10 ] dodecyl, 2-methyl-2-adamantyl, 2-ethyl-2-adamantyl, 1-methyl-3-oxo-1-cyclohexyl, 1-methyl-1-(tetrahydrofuran-2-yl)ethyl, 5-hydroxy-2-methyl-2-adamantyl, 5-hydroxy-2-ethyl-2-adamantyl, but are not limited to these.

[0404] In addition, the aforementioned acid-labile group is, for example, a group represented by the following formula (B2-1-1). The group represented by formula (B2-1-1) is often used as an acid-labile group and is a useful option as an acid-labile group that stabilizes the pattern and the substrate to give the pattern a relatively rectangular interface. When X is a group represented by formula (B2-1-1), an acetal structure is formed.

[0405] [Chemistry 116]

[0406]

[0407] In the formula, the chain line represents the bond hand.

[0408] In formula (B2-1-1), R L1 It is a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms. The saturated hydrocarbon group may be linear, branched or cyclic.

[0409] R L1 The decomposable group can be appropriately selected according to the design of the acid sensitivity. For example, in order to ensure relatively high stability, if the design is to be decomposed by strong acid, it is better to use a tertiary carbon atom as the carbon atom bonded to the hydrogen atom or the acetal carbon. L1 Examples of the group include, but are not limited to, tert-butyl, tert-amyl, and 1-adamantyl. If a design is used that is highly reactive and highly sensitive to pH changes, a straight-chain alkyl group is preferred. It also depends on the combination of the acid generator and quencher mixed in the resist composition, but for R L2 For example, when a relatively large alkyl group is selected at the end and the solubility change due to decomposition is large, R L1 , preferably the carbon atom bonded to the acetal carbon is a secondary carbon atom. L1 Examples of include, but are not limited to, isopropyl, sec-butyl, cyclopentyl, and cyclohexyl.

[0410] In formula (B2-1-1), RL2 The hydrocarbon group may be saturated or unsaturated, linear, branched, or cyclic. A portion of the -CH2- of the hydrocarbon group may be substituted by heteroatoms such as oxygen atoms or sulfur atoms, and may contain ether bonds or thioether bonds. Specific examples of the hydrocarbon group include saturated hydrocarbon groups with 1 to 30 carbon atoms and aromatic groups with 6 to 30 carbon atoms. In particular, in order to obtain higher resolution in fine pattern formation, R L2 It is preferably a hydrocarbon group having 1 to 6 carbon atoms. L2 In the case of a hydrocarbon group having 1 to 6 carbon atoms, the alcohol generated by the deprotection reaction with an acid is water-soluble, and therefore it dissolves in the developer when a positive pattern is formed with an alkaline developer, thereby suppressing residue defects in the exposed portion.

[0411] Preferred examples of the group represented by formula (B2-1-1) include the following, but are not limited to these. L1 As before, the chain lines represent the bond hands.

[0412] [Chemistry 117]

[0413]

[0414] [Chemistry 118]

[0415]

[0416] As for other acid-labile groups, those in which the hydrogen atom of the phenolic hydroxyl group is replaced by -CH2COO- (saturated tertiary hydrocarbon group) can also be used. In this case, the saturated tertiary hydrocarbon group can be the same as the saturated tertiary hydrocarbon group used for the protection of the phenolic hydroxyl group.

[0417] The repeating unit B2 may also be a repeating unit represented by the following formula (B2-2) (hereinafter also referred to as repeating unit B2-2). The repeating unit B2-2 is a useful option as a unit containing an acid-labile group that improves the dissolution rate of the exposed portion and provides good performance for line width variation under development load.

[0418] [Chemistry 119]

[0419]

[0420] In formula (B2-2), c1 is an integer of 0 to 2. c2 is an integer of 0 to 2. c3 is an integer of 0 to 5. c4 is an integer of 0 to 2.

[0421] In formula (B2-2), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0422] In formula (B2-2), R 13 and R 14Each independently represents a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom, R 13 With R 14 They may also be bonded to each other and to the carbon atoms to which they are bonded to form a ring.

[0423] In formula (B2-2), R 15 Each independently represents a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms.

[0424] In formula (B2-2), R 16 Each independently represents a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom.

[0425] In formula (B2-2), A 3 is a single bond, phenylene, naphthylene or *-C(=O)-OA 31 -.A 31 It is an aliphatic alkylene group having 1 to 20 carbon atoms which may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group. * represents an atomic bond to a carbon atom of the main chain.

[0426] Preferred examples of repeating unit B2-2 are listed below, but are not limited thereto. A Same as above.

[0427] [Chemistry 120]

[0428]

[0429] [Chemistry 121]

[0430]

[0431] The content of the repeating unit B2 is preferably 5 to 95 mol%, more preferably 20 to 80 mol%, of all the repeating units constituting the polymer. The repeating unit B2 may be used alone or in combination of two or more.

[0432] The aforementioned polymer may also contain at least one selected from the repeating unit represented by the following formula (B3) (hereinafter also referred to as repeating unit B3), the repeating unit represented by the following formula (B4) (hereinafter also referred to as repeating unit B4) and the repeating unit represented by the following formula (B5) (hereinafter also referred to as repeating unit B5).

[0433] [Chemistry 122]

[0434]

[0435] In formulae (B3) and (B4), d is an integer of 0-6. e is an integer of 0-4.

[0436] In formula (B3) and (B4), R 17 and R 18 Each independently represents a hydroxyl group, a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom. The saturated hydrocarbon group, saturated hydrocarbon oxy group, and saturated hydrocarbon carbonyloxy group may be straight-chain, branched, or cyclic. When d is 2 or more, each R 17 They may be the same or different from each other. When e is 2 or more, each R 18 They may be the same as or different from each other.

[0437] In formula (B5), f1 is 0 or 1. f2 is an integer of 0 to 2, and when 0 is a benzene skeleton, when 1 is a naphthalene skeleton, and when 2 is an anthracene skeleton. f3 is an integer of 0 to 5. When f2 is 0, f3 is preferably an integer of 0 to 3, and when f2 is 1 or 2, f3 is preferably an integer of 0 to 4.

[0438] In formula (B5), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0439] In formula (B5), R 19 is a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbon oxy group having 1 to 20 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbon oxyalkyl group having 2 to 20 carbon atoms, a saturated hydrocarbon thioalkyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, or a cyano group. When f2 is 1 or 2, it may also be a hydroxyl group. The saturated hydrocarbon group, saturated hydrocarbon oxy group, saturated hydrocarbon carbonyloxy group, saturated hydrocarbon oxyalkyl group, and saturated hydrocarbon thioalkyl group may be straight-chain, branched, or cyclic. When f3 is 2 or more, each R 19 They may be the same as or different from each other.

[0440] In formula (B5), A 4 is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a portion of the -CH2- in the saturated alkylene group may be substituted by -O-. The saturated alkylene group may be linear, branched, or cyclic. A specific example of the saturated alkylene group is: 1 The description exemplifies the same example.

[0441] When at least one of the repeating units B3 to B5 is used as a constituent unit of the polymer, in addition to the etching resistance of the aromatic ring, the effect of improving etching resistance and EB irradiation resistance during pattern inspection by adding a ring structure to the main chain can be obtained.

[0442] In order to obtain the effect of improving etching resistance, the content of repeating units B3 to B5 is preferably 5 mol% or more of all repeating units constituting the aforementioned polymer. In addition, the content of repeating units B3 to B5 is preferably 25 mol% or less of all repeating units constituting the aforementioned polymer, and more preferably 20 mol% or less. When there is no functional group or the functional group is other than hydroxyl, the introduction amount is 25 mol% or less, so there is no risk of developing defects, which is ideal. Repeating units B3 to B5 can be used alone or in combination of two or more.

[0443] The polymer preferably contains at least one selected from repeating unit B1, repeating unit B2, and repeating units B3 to B5, from the viewpoint of excellent compatibility of high etching resistance and resolution. In this case, the repeating units preferably account for 60 mol% or more of all repeating units in the polymer, more preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more.

[0444] The aforementioned polymer may also contain at least one selected from the repeating unit represented by the following formula (B6) (hereinafter also referred to as repeating unit B6), the repeating unit represented by the following formula (B7) (hereinafter also referred to as repeating unit B7), the repeating unit represented by the following formula (B8) (hereinafter also referred to as repeating unit B8), and the repeating unit represented by the following formula (B9) (hereinafter also referred to as repeating unit B9).

[0445] [Chemistry 123]

[0446]

[0447] In formulas (B6) to (B9), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 is a single bond or a phenylene group. 2 for* 1 -C(=O)-OX 21 -, * 1 -C(=O)-NH-X 21 -or* 1 -OX 21 -.X 21 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 1 Indicates and X 1 Atomic bonds. 3 Each independently represents a single bond, phenylene, naphthylene or * 2 -C(=O)-OX 31 -.X 31It is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, and the aliphatic alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring. 2 Represents the atomic bond between the carbon atoms of the main chain. 4 Each is independently a single bond, * 3 -X 41 -C(=O)-O-,* 3 -C(=O)-NH-X 41 -or* 3 -OX 41 -.X 41 It is a carbon number 1-20 alkylene group which may contain a hetero atom. * 3 Indicates and X 3 Atomic bonds. 5 Each is independently a single bond, * 4 -X 51 -C(=O)-O-,* 4 -C(=O)-NH-X 51 -or* 4 -OX 51 -.X 51 It is a carbon number 1-20 alkylene group which may contain a hetero atom. * 4 Indicates and X 4 Atomic bonds. 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, * 2 -C(=O)-OX 61 -, * 2 -C(=O)-N(H)-X 61 -or* 2 -OX 61 -.X 61 It is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group. 2 Represents the atomic bonds between carbon atoms in the main chain.

[0448] X 21 , X 31 and X 61The aliphatic alkylene group represented may be straight-chain, branched or cyclic, and specific examples thereof include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-2,2-diyl, butane-1,1-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-2,3-diyl, butane-1,4-diyl, 1,1-dimethylethane-1,2-diyl, pentane-1,5-diyl, 2-methylbutane-1,2-diyl, hexane-1,6-diyl; cycloalkanediyl such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl and cyclohexanediyl; and groups obtained by combining them.

[0449] X 41 and X 51 The alkylene group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the following, but are not limited to these.

[0450] [Chemistry 124]

[0451]

[0452] In the formula, the chain line represents the bond hand.

[0453] In formula (B6), R 21 and R 22 Each is independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and thienyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining them, among which aryl groups are preferred. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, the hydrocarbon group may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0454] Again, R 21 and R22 They may also be bonded to each other and to form a ring together with the sulfur atom to which they are bonded. In this case, the aforementioned ring, for example, and R in the description of formula (cation-1) ct1 and R ct2 Examples of the ring that can be formed together with the sulfur atom to which they are bonded are the same as those shown in FIG.

[0455] Specific examples of the cation of the repeating unit B6 are listed below, but are not limited to these. A Same as above.

[0456] [Chemistry 125]

[0457]

[0458] [Chemistry 126]

[0459]

[0460] [Chemistry 127]

[0461]

[0462] [Chemistry 128]

[0463]

[0464] [Chemistry 129]

[0465]

[0466] [Chemistry 130]

[0467]

[0468] [Chemistry 131]

[0469]

[0470] In formula (B6), M -It is a non-nucleophilic relative ion. The aforementioned non-nucleophilic relative ion is preferably a halide ion, a sulfonic acid anion, an imidic acid anion and a methylated acid anion. Specific examples of the aforementioned halide ion include chloride ions, bromide ions, etc. Specific examples of the aforementioned sulfonic acid anions (sulfonate ions) include fluoroalkylsulfonate ions such as trifluoromethanesulfonate ions, 1,1,1-trifluoroethanesulfonate ions, and nonafluorobutanesulfonate ions; arylsulfonate ions such as toluenesulfonate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, and 1,2,3,4,5-pentafluorobenzenesulfonate ions; alkylsulfonate ions such as methanesulfonate ions and butanesulfonate ions, etc. Specific examples of the aforementioned imidic acid anions (imide ions) include bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, bis(perfluorobutylsulfonyl)imide ions, etc. Specific examples of the methylated acid anion (methide ion) include tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0471] Other examples of the non-nucleophilic counter ion include an anion represented by any one of the following formulae (B6-1) to (B6-4).

[0472] [Chemistry 132]

[0473]

[0474] In formula (B6-1), R fa is a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented are exemplified by the same examples.

[0475] The anion represented by the formula (B6-1) is preferably represented by the following formula (B6-1-1).

[0476] [Chemistry 133]

[0477]

[0478] In formula (B6-1-1), Q 11 and Q 12 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, but in order to improve solvent solubility, at least one of them is preferably a trifluoromethyl group. m is an integer of 0 to 4, and 1 is particularly preferred. fa1It is a hydrocarbon group having 1 to 35 carbon atoms which may contain a hetero atom. The hetero atom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and an oxygen atom is more preferably. The hydrocarbon group preferably has 6 to 30 carbon atoms from the viewpoint of obtaining a high resolution when forming a fine pattern.

[0479] In formula (B6-1-1), R fa1 The hydrocarbon group having 1 to 35 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 35 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecanyl and eicosyl; cyclic saturated hydrocarbon groups having 3 to 35 carbon atoms, such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecyl, tetracyclododecylmethyl and dicyclohexylmethyl; unsaturated aliphatic hydrocarbon groups having 2 to 35 carbon atoms, such as allyl and 3-cyclohexenyl; aryl groups having 6 to 35 carbon atoms, such as phenyl, 1-naphthyl, 2-naphthyl and 9-fluorenyl; aralkyl groups having 7 to 35 carbon atoms, such as benzyl and diphenylmethyl; groups obtained by combining these groups, etc.

[0480] In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Examples of the hydrocarbon group containing a hetero atom include a tetrahydrofuranyl 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.

[0481] In formula (B6-1-1), L a1 It is a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond, but from the viewpoint of synthesis, an ether bond or an ester bond is preferred, and an ester bond is more preferred.

[0482] The anions represented by formula (B6-1) include, but are not limited to, the following. 11 As mentioned above, Ac is acetyl.

[0483] [Chemistry 134]

[0484]

[0485] [Chemistry 135]

[0486]

[0487] [Chemistry 136]

[0488]

[0489] [Chemistry 137]

[0490]

[0491] [Chemistry 138]

[0492]

[0493] [Chemistry 139]

[0494]

[0495] [Chemistry 140]

[0496]

[0497] [Chemistry 141]

[0498]

[0499] [Chemistry 142]

[0500]

[0501] [Chemistry 143]

[0502]

[0503] In formula (B6-2), R fb1 and R fb2 Each is independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are exemplified by the same examples. fb1 and R fb2 Preferably, it is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 They can also bond to each other and to the groups to which they are bonded (-CF2-SO2-N - -SO2-CF2-) together to form a ring. In this case, R fb1 and R fb2The group obtained by bonding to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0504] In formula (B6-3), R fc1 , R fc2 and R fc3 Each is independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented by are exemplified by the same examples. fc1 , R fc2 and R fc3 Preferably, it is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 They can also bond to each other and to the groups to which they are bonded (-CF2-SO2-C - -SO2-CF2-) together to form a ring. In this case, R fc1 and R fc2 The groups obtained by bonding to each other are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0505] In formula (B6-4), R fd is a hydrocarbon group having 1 to 40 carbon atoms which may contain heteroatoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The hydrocarbon groups represented are exemplified by the same examples.

[0506] The anions represented by the formula (B6-4) include the following, but are not limited to these.

[0507] [Chemistry 144]

[0508]

[0509] [Chemistry 145]

[0510]

[0511] Examples of the non-nucleophilic counter ion include anions having an aromatic ring substituted with an iodine atom or a bromine atom. Specific examples of such anions include those represented by the following formula (B6-5).

[0512] [Chemistry 146]

[0513]

[0514] In formula (B6-5), p is an integer satisfying 1≤p≤3. q and r are integers satisfying 1≤q≤5, 0≤r≤3 and 1≤q+r≤5. q is preferably 1, 2 or 3, more preferably 2 or 3. r is preferably 0, 1 or 2.

[0515] In formula (B6-5), X BI is an iodine atom or a bromine atom, and when p and / or q are 2 or more, they may be the same as or different from each other.

[0516] In formula (B6-5), L 1 It is a saturated alkylene group having 1 to 6 carbon atoms which may contain a single bond, an ether bond or an ester bond. The saturated alkylene group may be linear, branched or cyclic.

[0517] In formula (B6-5), L 2 When p is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms. When p is 2 or 3, it is a (p+1)-valent linking group having 1 to 20 carbon atoms. The linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.

[0518] In formula (B6-5), R fe is a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbonoxy group having 1 to 20 carbon atoms, a hydrocarboncarbonyl group having 2 to 20 carbon atoms, a hydrocarbonoxycarbonyl group having 2 to 20 carbon atoms, a hydrocarboncarbonyloxy group having 2 to 20 carbon atoms or a hydrocarbonsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group or an ether bond, or -N(R feA )(R feB )、-N(R feC )-C(=O)-R feD or -N(R feC )-C(=O)-OR feD . R feA and R feB Each R is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. feC R is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. feD It is an aliphatic hydrocarbon group having 1 to 16 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. The aforementioned hydrocarbon group, hydrocarbonoxy group, hydrocarbon carbonyl group, hydrocarbon oxycarbonyl group, hydrocarbon carbonyloxy group, and hydrocarbon sulfonyloxy group may be straight-chain, branched, or cyclic. When p and / or r are 2 or more, each R feThey may be the same as or different from each other.

[0519] Among these, R fe Hydroxyl, -N(R feC )-C(=O)-R feD 、-N(R feC )-C(=O)-OR feD , fluorine atom, chlorine atom, bromine atom, methyl group, methoxy group and the like are preferred.

[0520] In formula (B6-5), Rf 11 ~Rf 14 Each independently represents a hydrogen atom, a fluorine atom or a trifluoromethyl group, and at least one of these is a fluorine atom or a trifluoromethyl group. 11 With Rf 12 They can also be combined to form a carbonyl group. 13 and Rf 14 All of them are preferably fluorine atoms.

[0521] The anions represented by formula (B6-5) include, but are not limited to, the following. BI Same as above.

[0522] [Chemistry 147]

[0523]

[0524] [Chemistry 148]

[0525]

[0526] [Chemistry 149]

[0527]

[0528] [Chemistry 150]

[0529]

[0530] [Chemistry 151]

[0531]

[0532] [Chemistry 152]

[0533]

[0534] [Chemistry 153]

[0535]

[0536] [Chemistry 154]

[0537]

[0538] [Chemistry 155]

[0539]

[0540] [Chemistry 156]

[0541]

[0542] [Chemistry 157]

[0543]

[0544] [Chemistry 158]

[0545]

[0546] [Chemistry 159]

[0547]

[0548] [Chemistry 160]

[0549]

[0550] [Chemistry 161]

[0551]

[0552] [Chemistry 162]

[0553]

[0554] [Chemistry 163]

[0555]

[0556] [Chemistry 164]

[0557]

[0558] [Chemistry 165]

[0559]

[0560] [Chemistry 166]

[0561]

[0562] [Chemistry 167]

[0563]

[0564] [Chemistry 168]

[0565]

[0566] [Chemistry 169]

[0567]

[0568] The aforementioned non-nucleophilic counter ions may also include fluorobenzenesulfonic acid anions bonded to an aromatic group containing an iodine atom as described in Japanese Patent No. 6648726, anions having a mechanism of acid decomposition as described in International Publication No. 2021 / 200056 and Japanese Patent Application Publication No. 2021-70692, anions having a cyclic ether group as described in Japanese Patent Application Publication No. 2018-180525 and Japanese Patent Application Publication No. 2021-35935, and anions as described in Japanese Patent Application Publication No. 2018-92159.

[0569] The non-nucleophilic counter ions may further include anions of fluorine-free thiocyanate derivatives described in Japanese Patent Application Publication Nos. 2006-276759, 2015-117200, 2016-65016, and 2019-202974, and benzenesulfonic acid anions and alkylsulfonic acid anions that are bonded to an aromatic group containing an iodine atom and described in Japanese Patent No. 6645464.

[0570] The aforementioned non-nucleophilic counter ion may further include anions of disulfonic acids described in JP-A-2015-206932, anions of sulfonic acids on one side and sulfonamides or sulfonimides different therefrom described in WO2020 / 158366, and anions of sulfonic acids on one side and carboxylic acids on the other side described in JP-A-2015-24989.

[0571] In formula (B7) and (B8), L 1 It is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond. Among these, an ether bond, an ester bond and a carbonyl group are preferred from the viewpoint of synthesis, and an ester bond and a carbonyl group are more preferred.

[0572] In formula (B7), Rf 1 and Rf 2 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 1 and Rf 2 In order to increase the acid strength of the generated acid, fluorine atoms are preferred. 3 and Rf 4 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. Among these, Rf 3 and Rf 4Preferably, at least one of them is trifluoromethyl.

[0573] In formula (B8), Rf 5 and Rf 6 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 5 and Rf 6 At the same time, it becomes a hydrogen atom. Among these, in order to improve the solvent solubility, Rf 5 and Rf 6 Preferably, at least one of them is trifluoromethyl.

[0574] In formulae (B7) and (B8), g1 and g2 are integers of 0 to 3, preferably 1.

[0575] Specific examples of anions of the repeating unit B7 include the following, but are not limited to these. A Same as above.

[0576] [Chemistry 170]

[0577]

[0578] [Chemistry 171]

[0579]

[0580] [Chemistry 172]

[0581]

[0582] [Chemistry 173]

[0583]

[0584] [Chemistry 174]

[0585]

[0586] [Chemistry 175]

[0587]

[0588] [Chemistry 176]

[0589]

[0590] Specific examples of anions of the repeating unit B8 are listed below, but are not limited to these. A Same as above.

[0591] [Chemistry 177]

[0592]

[0593] [Chemistry 178]

[0594]

[0595] [Chemistry 179]

[0596]

[0597] [Chemistry 180]

[0598]

[0599] [Chemistry 181]

[0600]

[0601] [Chemistry 182]

[0602]

[0603] [Chemistry 183]

[0604]

[0605] Specific examples of anions of the repeating unit B9 include the following, but are not limited thereto. A Same as above.

[0606] [Chemistry 184]

[0607]

[0608] In formulas (B6) to (B9), A + is an onium cation. The onium cation is, for example, a sulfonium cation, an iodonium cation, an ammonium cation, etc., preferably a sulfonium cation or an iodonium cation. Specific examples of the sulfonium cation are the same as those given for the specific examples of the sulfonium cation represented by formula (cation-1). Specific examples of the iodonium cation are the same as those given for the specific examples of the iodonium cation represented by formula (cation-2).

[0609] Repeating units B6 to B9 are units that generate acid by irradiation with high-energy rays. By including these units in the polymer, it is believed that acid diffusion is moderately suppressed, and a pattern with reduced LER can be obtained. In addition, by including these units in the polymer, when baking in a vacuum, the phenomenon that the acid evaporates from the exposed part and reattaches to the unexposed part is suppressed, and it is believed that it is effective in reducing LER and reducing the shape degradation caused by the loss of the unexposed film in the unexposed part.

[0610] Among repeating units B6 to B9, as ideal units for blank photomask processing, repeating units B7 to B9 are more ideal from the viewpoint of optimal acid strength in terms of suppressing acid diffusion and designing acid-labile groups of polymers, and repeating units B7 and B8 are more ideal.

[0611] The repeating units B6 to B9 are preferably introduced in an amount of 0.1 to 30 mol %, more preferably 0.5 to 20 mol %, in all the repeating units of the polymer. The repeating units B6 to B9 may be used alone or in combination of two or more.

[0612] The content of repeating units having an aromatic ring skeleton in all repeating units of the above polymer is preferably 65 mol% or more, more preferably 75 mol% or more, and even more preferably 85 mol% or more. When repeating units B6 to B9 are not contained, all units preferably have an aromatic ring skeleton.

[0613] The polymer may also contain a (meth)acrylate unit protected by a conventional acid-labile group, or a (meth)acrylate unit having a lactone structure, a hydroxyl group other than a phenolic hydroxyl group, or other adhesion groups. The repeating unit may be used to fine-tune the properties of the resist film, but the unit may not be contained.

[0614] Examples of the aforementioned (meth)acrylate units with adhesion groups include repeating units represented by the following formula (B10) (hereinafter referred to as repeating units B10), repeating units represented by the following formula (B11) (hereinafter referred to as repeating units B11), and repeating units represented by the following formula (B12) (hereinafter referred to as repeating units B12). These units do not show acidity and can be used as auxiliary units for adjusting adhesion to a substrate or adjusting solubility.

[0615] [Chemistry 185]

[0616]

[0617] In formulas (B10) to (B12), R A R is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 31 is -O- or methylene. 32 is a hydrogen atom or a hydroxyl group. 33 is a saturated hydrocarbon group having 1 to 4 carbon atoms. h is an integer of 0 to 3.

[0618] When repeating units B10 to B12 are contained, their content is preferably 0 to 20 mol%, more preferably 0 to 10 mol%, of all repeating units of the above polymer. Repeating units B10 to B12 may be used alone or in combination of two or more.

[0619] The above-mentioned polymer can be synthesized by copolymerizing monomers protected by protective groups as needed using a known method, and then performing a deprotection reaction as needed. The copolymerization reaction is not particularly limited, and is preferably free radical polymerization or anionic polymerization. For these methods, reference can be made to Japanese Patent Publication No. 2004-115630.

[0620] The weight average molecular weight (Mw) of the aforementioned polymer is preferably 1000 to 50000, and more preferably 2000 to 20000. If the Mw is 1000 or more, there is no risk of the phenomenon of rounding of the pattern top, reduction of resolution and LER degradation as known in the past. On the other hand, if the Mw is 50000 or less, there is no risk of LER degradation, especially when forming a pattern with a line width of 100 nm or less. In addition, in the present invention, Mw is a polystyrene-converted measurement value obtained by gel permeation chromatography (GPC) using THF or DMF as a solvent.

[0621] The polymer preferably has a narrow molecular weight distribution (Mw / Mn) of 1.0 to 2.0, preferably 1.0 to 1.9, and more preferably 1.0 to 1.8. When the polymer has such a narrow distribution, no foreign matter will appear on the pattern after development, and the shape of the pattern will not be deteriorated.

[0622] Furthermore, the above-mentioned base polymer is designed to have a dissolution rate of 10 nm / min or less for the alkaline developer, preferably 7 nm / min or less, and even more preferably 5 nm / min or less. In the advanced generation, when the coating film on the substrate is in the thin film range (less than 100 nm), the influence of the pattern film loss on the alkaline development increases. When the alkaline dissolution rate of the polymer is greater than 10 nm / min, the pattern collapses and it becomes impossible to form a fine pattern. Especially in the production of photomasks that require no defects, there is a tendency for the development process to be strong, so it is significant. Furthermore, in the present invention, the dissolution rate of the base polymer in the alkaline developer is the value calculated from the film loss amount when the polymer solution (polymer concentration: 16.7 mass%, solvent: propylene glycol monomethyl ether acetate (PGMEA)) is spin-coated on an 8-inch silicon wafer, baked at 100°C for 90 seconds, and a film with a film thickness of 1000 nm is formed, and then developed with a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution at 23°C for 100 seconds.

[0623] The base polymer of component (B) may also contain other polymers other than the aforementioned polymers. Other polymers may be those that are conventionally known as base polymers for resist compositions. The content of other polymers is not particularly limited as long as it does not impair the effects of the present invention.

[0624] [(C) Organic solvent]

[0625] The resist composition of the present invention may also contain an organic solvent as component (C). The aforementioned organic solvent is not particularly limited as long as it can dissolve the various components. Such organic solvents include, for example, ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone described in paragraphs

[0144] to

[0145] of Japanese Patent Publication No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether (PGME), ethyl Ethers such as glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate (EL), ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as γ-butyrolactone; and mixed solvents thereof. When an acetal-based acid-labile group is used, a high-boiling alcohol solvent may be added to accelerate the deprotection reaction of the acetal, and specifically, diethylene glycol, propylene glycol, glycerol, 1,4-butanediol, 1,3-butanediol, and the like may be added.

[0626] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, and mixed solvents thereof are preferred.

[0627] When the chemically amplified positive resist composition of the present invention contains (C) an organic solvent, its content is preferably 200 to 10,000 parts by mass, more preferably 400 to 5,000 parts by mass, relative to 80 parts by mass of the base polymer (B). The organic solvent (C) may be used alone or in combination of two or more.

[0628] [(D) Fluorine-containing polymer]

[0629] The chemically amplified positive resist composition of the present invention may contain at least one of a repeating unit selected from the group consisting of a repeating unit represented by the following formula (D1) (hereinafter also referred to as repeating unit D1), a repeating unit represented by the following formula (D2) (hereinafter also referred to as repeating unit D2), a repeating unit represented by the following formula (D3) (hereinafter also referred to as repeating unit D3), and a repeating unit represented by the following formula (D4) (hereinafter also referred to as repeating unit D4), and may further contain at least one of a repeating unit represented by the following formula (D5) (hereinafter also referred to as repeating unit D5) and a repeating unit represented by the following formula (D6) (hereinafter also referred to as repeating unit D6) as a fluorine atom-containing polymer in order to achieve high contrast, suppress the chemical flash phenomenon of acid during high-energy ray irradiation, and shield the mixing of acid from the antistatic film when the antistatic film material is applied to the photoresist to suppress unexpected and unwanted pattern degradation. The aforementioned fluorine-atom-containing polymer also has an interfacial active function, and thus can prevent the phenomenon in which insoluble matter that may occur during the development process is reattached to the substrate, and also has an effect on development defects.

[0630] [Chemistry 186]

[0631]

[0632] In formulas (D1) to (D6), j1 is an integer of 1 to 3. j2 is an integer satisfying 0≤j2≤5+2(j3)-j1. j3 is 0 or 1. k is an integer of 1 to 3. R B R is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. C Each is independently a hydrogen atom or a methyl group. 101 , R 102 , R 104 and R 105 Each R is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms. 103 , R 106 , R 107 and R 108 are each independently a hydrogen atom, a hydrocarbon group having 1 to 15 carbon atoms, a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group, and R 103 , R 106 , R 107 and R 108 When it is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between the carbon-carbon bonds. 109 It is a hydrogen atom or a linear or branched hydrocarbon group having 1 to 5 carbon atoms, which may contain a hetero atom inserted between carbon-carbon bonds. 110 It is a linear or branched hydrocarbon group having 1 to 5 carbon atoms, which may contain a heteroatom-containing group inserted between carbon-carbon bonds. 111It is a saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted by a fluorine atom, and a part of the -CH2- of the saturated hydrocarbon group may be substituted by an ester bond or an ether bond. 1 Z is a (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond with a carbon atom of the main chain. Z 3 is a single bond, -O-, *-C(=O)-OZ 31 -Z 32 - or *-C(=O)-NH-Z 31 -Z 32 -.Z 31 Z is a single bond or a saturated alkylene group having 1 to 10 carbon atoms. 32 It is a single bond, ester bond, ether bond or sulfonamide bond. * indicates an atomic bond between the carbon atoms of the main chain.

[0633] In formula (D1) and (D2), R 101 , R 102 , R 104 and R 105 The saturated hydrocarbon group having 1 to 10 carbon atoms represented by ] may be straight-chain, branched or cyclic, and specific examples thereof include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl; and cyclic saturated hydrocarbon groups having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl and norbornyl. Among these, saturated hydrocarbon groups having 1 to 6 carbon atoms are preferred.

[0634] In formulas (D1) to (D4), R 103 , R 106 , R 107 and R 108 The hydrocarbon group having 1 to 15 carbon atoms may be straight chain, branched or cyclic, and specific examples thereof include alkyl groups having 1 to 15 carbon atoms, alkenyl groups having 2 to 15 carbon atoms, alkynyl groups having 2 to 15 carbon atoms, etc., but alkyl groups having 1 to 15 carbon atoms are preferred. The aforementioned alkyl groups may include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, etc. In addition, fluorinated hydrocarbon groups may be groups in which a part or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon groups are substituted with fluorine atoms.

[0635] In formula (D4), Z 1The (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms represented by is, for example, a group obtained by removing k hydrogen atoms from an alkyl group having 1 to 20 carbon atoms or a cyclic saturated hydrocarbon group having 3 to 20 carbon atoms. 1 The (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by is, for example, a group in which at least one hydrogen atom of the (k+1)-valent hydrocarbon group is substituted with a fluorine atom.

[0636] Specific examples of repeating units D1 to D4 are listed below, but are not limited to these. B Same as above.

[0637] [Chemistry 187]

[0638]

[0639] [Chemistry 188]

[0640]

[0641] [Chemistry 189]

[0642]

[0643] In formula (D5), R 109 and R 110 The hydrocarbon group having 1 to 5 carbon atoms represented by is, for example, an alkyl group, an alkenyl group, an alkynyl group, etc., and an alkyl group is preferred. The aforementioned alkyl group is, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, an n-pentyl group, etc. In addition, a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. may be inserted between the carbon-carbon bonds of the aforementioned hydrocarbon group.

[0644] In formula (D5), -OR 109 In this case, R 109 Preferred are hydrogen atoms, alkyl groups having 1 to 5 carbon atoms with an oxygen atom inserted between carbon-carbon bonds, and the like.

[0645] In formula (D5), Z 2 It is preferably *-C(=O)-O- or *-C(=O)-NH-. C Preferably, Z is methyl. 2 The presence of the carbonyl group improves the ability of the antistatic film to capture acid. C If it is a methyl group, it becomes a rigid polymer with a higher glass transition temperature (Tg), so the diffusion of acid is suppressed. As a result, the stability of the resist film over time becomes good, and the resolution and pattern shape do not deteriorate.

[0646] The repeating unit D5 may be exemplified as follows, but is not limited thereto. C Same as above.

[0647] [Chemistry 190]

[0648]

[0649] [Chemistry 191]

[0650]

[0651] In formula (D6), Z 3 The saturated alkylene group having 1 to 10 carbon atoms may be straight-chain, branched or cyclic, and specific examples thereof include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-2,2-diyl, butane-1,1-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-2,3-diyl, butane-1,4-diyl, 1,1-dimethylethane-1,2-diyl and the like.

[0652] In formula (D6), R 111 The saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is replaced by a fluorine atom may be straight-chain, branched or cyclic, and specific examples thereof include an alkyl group having 1 to 20 carbon atoms or a cyclic saturated hydrocarbon group having 3 to 20 carbon atoms in which at least one hydrogen atom is replaced by a fluorine atom.

[0653] The repeating unit D6 may be exemplified as follows, but is not limited thereto. C Same as above.

[0654] [Chemistry 192]

[0655]

[0656] [Chemistry 193]

[0657]

[0658] [Chemistry 194]

[0659]

[0660] [Chemistry 195]

[0661]

[0662] The content of repeating units D1 to D4 is preferably 15 to 95 mol %, more preferably 20 to 85 mol %, of all repeating units of the aforementioned fluorine-containing polymer. The content of repeating units D5 and / or D6 is preferably 5 to 85 mol %, more preferably 15 to 80 mol %, of all repeating units of the aforementioned fluorine-containing polymer. Repeating units D1 to D6 may be used alone or in combination of two or more.

[0663] (D) The fluorine-containing polymer may contain other repeating units other than the aforementioned repeating units. Such repeating units are described, for example, in paragraphs

[0046] to

[0078] of Japanese Patent Application Publication No. 2014-177407. When (D) the fluorine-containing polymer contains other repeating units, it is preferred that the content of the other repeating units is 50 mol% or less of all the repeating units of the aforementioned fluorine-containing polymer.

[0664] (D) Fluorine-containing polymers can be synthesized by copolymerizing monomers protected by protective groups as needed using a known method, and then performing a deprotection reaction as needed. The copolymerization reaction is not particularly limited, and is preferably free radical polymerization or anionic polymerization. For these methods, reference can be made to Japanese Patent Publication No. 2004-115630.

[0665] The Mw of the fluorine-containing polymer (D) is preferably 2000 to 50000, more preferably 3000 to 20000. If the Mw is less than 2000, acid diffusion will be promoted, and resolution may be degraded and stability over time may be impaired. If the Mw is too large, the solubility in the solvent is reduced, and coating defects may occur. In addition, the Mw / Mn of the fluorine-containing polymer (D) is preferably 1.0 to 2.2, and more preferably 1.0 to 1.7.

[0666] When the chemically amplified positive resist composition of the present invention contains (D) a fluorine-containing polymer, its content is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 80 parts by mass of the base polymer (B). The fluorine-containing polymer (D) may be used alone or in combination of two or more.

[0667] [(E) Quencher]

[0668] The chemically amplified positive resist composition of the present invention may contain a quencher as component (E) as necessary. In the present invention, the quencher refers to a compound that captures the acid from the acid generator. This can suppress the diffusion rate of the acid generated from the acid generator when diffusing in the resist film, and even when a substrate whose outermost surface is composed of a chromium-containing material is used as a substrate, the influence of the acid generated in the resist film on the chromium-containing material can be suppressed.

[0669] The quencher is, for example, a known basic compound. Known basic compounds include, for example, primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Application Laid-Open No. 2008-111103, especially amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate bond, or compounds having a carbamate group described in Japanese Patent No. 3790649 are preferred. Desirable examples include tris[2-(methoxymethoxy)ethyl]amine, tris[2-(methoxymethoxy)ethyl]amine-N-oxide, dibutylaminobenzoic acid, morpholine derivatives, imidazole derivatives, etc. By adding such a basic compound, for example, the diffusion rate of the acid in the resist film can be further suppressed or the shape can be corrected.

[0670] The quencher is, for example, an onium salt such as a sulfonium salt, an iodonium salt, or an ammonium salt of a carboxylic acid whose α-position is not fluorinated as described in Japanese Patent Application Laid-Open No. 2008-158339. Sulfonic acid, imidic acid, or methylated acid fluorinated at the α-position is necessary for deprotecting the acid-labile group, and the carboxylic acid whose α-position is not fluorinated is released by salt exchange with the onium salt whose α-position is not fluorinated. The carboxylic acid whose α-position is not fluorinated hardly undergoes a deprotection reaction, and thus acts as a quencher.

[0671] The onium salt of carboxylic acid whose α-position is not fluorinated is, for example, represented by the following formula (E1).

[0672] [Chemistry 196]

[0673] R 201 -CO2 - Mq A + (E1)

[0674] In formula (E1), R 201 A hydrocarbon group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, but excluding a hydrogen atom bonded to the carbon atom at the α-position of a carboxyl group substituted with a fluorine atom or a fluoroalkyl group.

[0675] R 201The hydrocarbon group represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms, such as methyl, ethyl, n-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, tricyclo[5.2.1.0 2,6 ] Cyclic saturated hydrocarbon groups having 3 to 40 carbon atoms, such as decyl, adamantyl, and adamantylmethyl; alkenyl groups having 2 to 40 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; cyclic unsaturated aliphatic hydrocarbon groups having 3 to 40 carbon atoms, such as cyclohexenyl; aryl groups having 6 to 40 carbon atoms, such as phenyl, naphthyl, alkylphenyl (2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 4-n-butylphenyl, etc.), di- or trialkylphenyl (2,4-dimethylphenyl, 2,4,6-triisopropylphenyl, etc.), alkylnaphthyl (methylnaphthyl, ethylnaphthyl, etc.), dialkylnaphthyl (dimethylnaphthyl, diethylnaphthyl, etc.); aralkyl groups having 7 to 40 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl, etc.

[0676] Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxyl group, a cyano group, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like. A hydrocarbon group containing a heteroatom, for example, a heteroaryl group such as a thienyl group; an alkoxyphenyl group such as 4-hydroxyphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 4-tert-butoxyphenyl, 3-tert-butoxyphenyl; an alkoxynaphthyl group such as a methoxynaphthyl, ethoxynaphthyl, n-propoxynaphthyl, n-butoxynaphthyl; a dialkoxynaphthyl group such as a dimethoxynaphthyl, diethoxynaphthyl; an aryloxyalkyl group such as a 2-aryl-2-oxoethyl group such as a 2-phenyl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, a 2-(2-naphthyl)-2-oxoethyl group, and the like.

[0677] In formula (E1), Mq A +It is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation or an ammonium cation, and more preferably a sulfonium cation or an iodonium cation. Specific examples of the sulfonium cation are the same as those given in the specific examples of the sulfonium cation represented by formula (cation-1). Specific examples of the iodonium cation are the same as those given in the specific examples of the iodonium cation represented by formula (cation-2).

[0678] Examples of anions of the onium salt represented by formula (E1) include the following, but are not limited to these.

[0679] [Chemistry 197]

[0680]

[0681] [Chemistry 198]

[0682]

[0683] [Chemistry 199]

[0684]

[0685] As the quencher, a sulfonium salt of a carboxylic acid containing an iodinated benzene ring represented by the following formula (E2) is also preferably used.

[0686] [Chemistry 200]

[0687]

[0688] In formula (E2), s is an integer of 1 to 5. t is an integer of 0 to 3, but 1≤s+t≤5. u is an integer of 1 to 3.

[0689] In formula (E2), R 211 is a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbon group having 1 to 6 carbon atoms, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms, or a saturated hydrocarbon sulfonyloxy group having 1 to 4 carbon atoms, which may be partially or entirely substituted with halogen atoms, or -N(R 211A )-C(=O)-R 211B or -N(R 211A )-C(=O)-OR 211B . R 211A is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. 221B is a saturated hydrocarbon group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 8 carbon atoms. When t and / or u is 2 or more, each R 211 They may be the same as or different from each other.

[0690] In formula (E2), L 11It is a single bond or a (u+1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxyl group, and a carboxyl group. The saturated hydrocarbon group, saturated hydrocarbon oxy group, saturated hydrocarbon carbonyloxy group, and saturated hydrocarbon sulfonyloxy group may be straight-chain, branched, or cyclic.

[0691] In formula (E2), R 212 , R 213 and R 214 Each is independently a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, and aralkyl groups having 7 to 20 carbon atoms. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a hydroxyl group, a carboxyl group, a halogen atom, an oxo group, a cyano group, a nitro group, a sultone ring, a sulfonium group, or a group containing a sulfonium salt, and a part of the -CH2- of the aforementioned hydrocarbon group may be substituted by an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate bond. Furthermore, R 212 and R 213 They may also bond to each other and to the sulfur atom to which they are bonded to form a ring.

[0692] Specific examples of the compound represented by formula (E2) are described in, for example, Japanese Patent Application Laid-Open No. 2017-219836. The compound represented by formula (E2) has high absorption and sensitization effect, and also has high acid diffusion control effect.

[0693] As the quencher, a nitrogen atom-containing carboxylate type compound represented by the following formula (E3) can also be used.

[0694] [Chemistry 201]

[0695]

[0696] In formula (E3), R 221 ~R 224 are each independently a hydrogen atom, -L 12 -CO2 - , or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 221 With R 222 , R 222 With R 223 , or R 223 With R 224 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring. 12 is a single bond or an alkylene group having 1 to 20 carbon atoms which may contain a hetero atom. 225 It is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hydrogen atom or a hetero atom.

[0697] In formula (E3), ring R r It is a ring having 2 to 6 carbon atoms and a nitrogen atom in the formula, and some or all of the hydrogen atoms bonded to the carbon atoms of the ring may be replaced by a hydrocarbon group having 1 to 20 carbon atoms, or -L 12 -CO2 - The ring may be substituted, and part of the carbon atoms of the ring may be substituted by sulfur atoms, oxygen atoms or nitrogen atoms. The aforementioned ring may be an alicyclic ring or an aromatic ring, and preferably a 5-membered ring or a 6-membered ring, and specific examples thereof include a pyridine ring, a pyrrole ring, a pyrrolidine ring, a piperidine ring, a pyrazole ring, an imidazoline ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an imidazoline ring, an oxazole ring, a thiazole ring, a morpholine ring, a thiazine ring, a triazole ring, and the like.

[0698] The carboxylic acid onium salt represented by formula (E3) has at least one -L 12 -CO2 - That is, R 221 ~R 224 At least one of them is -L 12 -CO2 - , and / or at least one of the hydrogen atoms bonded to the carbon atoms of ring R is replaced by -L 12 -CO2 - replace.

[0699] In formula (E3), Mq B + It is a sulfonium cation, an iodonium cation or an ammonium cation, and the sulfonium cation is preferred. Specific examples of the sulfonium cation are the same as those exemplified in the specific examples of the sulfonium cation represented by the formula (cation-1).

[0700] The anion of the compound represented by formula (E3) can be exemplified by the following, but is not limited thereto.

[0701] [Chemistry 202]

[0702]

[0703] [Chemistry 203]

[0704]

[0705] [Chemistry 204]

[0706]

[0707] [Chemistry 205]

[0708]

[0709] [Chemistry 206]

[0710]

[0711] [Chemistry 207]

[0712]

[0713] Furthermore, the aforementioned quencher may also be a weakly acidic betaine-type compound. Specific examples thereof include the following, but are not limited thereto.

[0714] [Chemistry 208]

[0715]

[0716] The aforementioned quencher may further include a polymer quencher described in Japanese Patent Application Publication No. 2008-239918. The polymer quencher improves the rectangularity of the resist pattern by being aligned on the surface of the resist film. The polymer quencher also has the effect of preventing film loss and rounding of the pattern top when using a protective film for wet exposure.

[0717] When the chemically amplified positive resist composition of the present invention contains a quencher, its content is preferably 0 to 50 parts by weight, more preferably 0.1 to 40 parts by weight, relative to 80 parts by weight of the base polymer. The quencher may be used alone or in combination of two or more.

[0718] When the chemically amplified positive resist composition of the present invention contains both a photoacid generator and a quencher, the content ratio of the photoacid generator to the quencher (photoacid generator / quencher) is preferably less than 3, more preferably less than 2.5, and more preferably less than 2 in terms of mass ratio. When the content ratio of the photoacid generator to the quencher in the chemically amplified positive resist composition is within the above range, acid diffusion can be sufficiently suppressed, and excellent resolution and dimensional uniformity can be obtained.

[0719] [(F) Other photoacid generators]

[0720] The chemically amplified positive resist composition of the present invention may also contain other photoacid generators other than the photoacid generator composed of the onium salt represented by formula (A) and the polymer-bonded photoacid generator represented by formulas (B6) to (B9). The aforementioned other photoacid generators are not particularly limited as long as they are compounds that generate acid when irradiated with high-energy rays. Ideal photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, etc.

[0721] Specific examples of the aforementioned other photoacid generators include nonafluorobutane sulfonates, partially fluorinated sulfonates described in paragraphs

[0247] to

[0251] of Japanese Patent Publication No. 2012-189977, partially fluorinated sulfonates described in paragraphs

[0261] to

[0265] of Japanese Patent Publication No. 2013-101271, paragraphs

[0122] to

[0142] of Japanese Patent Publication No. 2008-111103, and paragraphs

[0080] to

[0081] of Japanese Patent Publication No. 2010-215608. Among the aforementioned specific examples, arene sulfonate-type or alkane sulfonate-type photoacid generators are ideal because they generate an acid of moderate strength for deprotecting the acid-labile group of the repeating unit B2.

[0722] Such a photoacid generator is preferably a salt compound containing the following anions.

[0723] [Chemistry 209]

[0724]

[0725] [Chemistry 210]

[0726]

[0727] [Chemistry 211]

[0728]

[0729] [Chemistry 212]

[0730]

[0731] [Chemistry 213]

[0732]

[0733] [Chemistry 214]

[0734]

[0735] [Chemistry 215]

[0736]

[0737] [Chemistry 216]

[0738]

[0739] [Chemistry 217]

[0740]

[0741] [Chemistry 218]

[0742]

[0743] [Chemistry 219]

[0744]

[0745] [Chemistry 220]

[0746]

[0747] [Chemistry 221]

[0748]

[0749] [Chemistry 222]

[0750]

[0751] [Chemistry 223]

[0752]

[0753] [Chemistry 224]

[0754]

[0755] [Chemistry 225]

[0756]

[0757] [Chemistry 226]

[0758]

[0759] [Chemistry 227]

[0760]

[0761] [Chemistry 228]

[0762]

[0763] [Chemistry 229]

[0764]

[0765] [Chemistry 230]

[0766]

[0767] [Chemistry 231]

[0768]

[0769] [Chemistry 232]

[0770]

[0771] [Chemistry 233]

[0772]

[0773] [Chemistry 234]

[0774]

[0775] [Chemistry 235]

[0776]

[0777] [Chemistry 236]

[0778]

[0779] [Chemistry 237]

[0780]

[0781] [Chemistry 238]

[0782]

[0783] [Chemistry 239]

[0784]

[0785] [Chemistry 240]

[0786]

[0787] [Chemistry 241]

[0788]

[0789] [Chemistry 242]

[0790]

[0791] [Chemistry 243]

[0792]

[0793] [Chemistry 244]

[0794]

[0795] [Chemistry 245]

[0796]

[0797] [Chemistry 246]

[0798]

[0799] [Chemistry 247]

[0800]

[0801] [Chemistry 248]

[0802]

[0803] [Chemistry 249]

[0804]

[0805] [Chemistry 250]

[0806]

[0807] [Chemistry 251]

[0808]

[0809] [Chemistry 252]

[0810]

[0811] [Chemistry 253]

[0812]

[0813] [Chemistry 254]

[0814]

[0815] [Chemistry 255]

[0816]

[0817] [Chemistry 256]

[0818]

[0819] [Chemistry 257]

[0820]

[0821] [Chemistry 258]

[0822]

[0823] [Chemistry 259]

[0824]

[0825] [Chemistry 260]

[0826]

[0827] [Chemistry 261]

[0828]

[0829] [Chemistry 262]

[0830]

[0831] [Chemistry 263]

[0832]

[0833] [Chemistry 264]

[0834]

[0835] [Chemistry 265]

[0836]

[0837] [Chemistry 266]

[0838]

[0839] [Chemistry 267]

[0840]

[0841] [Chemistry 268]

[0842]

[0843] [Chemistry 269]

[0844]

[0845] Furthermore, the photoacid generator is preferably a salt compound containing an anion represented by the following formula (F1).

[0846] [Chemistry 270]

[0847]

[0848] In formula (F1), m1 is 0 or 1. x is an integer of 1 to 3. y is an integer of 1 to 5. z is an integer of 0 to 3. However, 1≤y+z≤5.

[0849] In formula (F1), L 21 It is a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond.

[0850] In formula (F1), L 22It is an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond.

[0851] In formula (F1), L D When x is 1, it is a single bond or an alkylene group having 1 to 20 carbon atoms; when x is 2 or 3, it is an (x+1)-valent hydrocarbon group having 1 to 20 carbon atoms. The alkylene group and the (x+1)-valent hydrocarbon group may also contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxyl group and a carboxyl group.

[0852] L D The alkylene group having 1 to 20 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups having 1 to 20 carbon atoms, such as methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, 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, and dodecane-1,12-diyl; cyclic saturated alkylene groups having 3 to 20 carbon atoms, such as cyclopentanediyl, cyclohexanediyl, norbornanediyl, and adamantanediyl; unsaturated aliphatic alkylene groups having 2 to 20 carbon atoms, such as vinylene and propylene-1,3-diyl; arylene groups having 6 to 20 carbon atoms, such as phenylene and naphthylene; and groups obtained by combining these. In addition, L D The (x+1)-valent hydrocarbon group having 1 to 20 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include groups obtained by removing one or two hydrogen atoms from the above-mentioned specific examples of the hydrocarbon group having 1 to 20 carbon atoms.

[0853] In formula (F1), Rf 21 and Rf 22 Each is independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, and at least one is a fluorine atom or a trifluoromethyl group.

[0854] In formula (F1), R 301 is a hydroxyl group, a carboxyl group, a saturated hydrocarbon group having 1 to 6 carbon atoms, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, -N(R 301A )(R 301B )、-N(R 301C )-C(=O)-R 301D or -N(R 301C )-C(=O)-OR 301D . R 301A and R 301B Each R is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. 301Cis a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. 301D It is a saturated hydrocarbon group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 8 carbon atoms.

[0855] R 301 , R 301A , R 301B and R 301C The saturated hydrocarbon group having 1 to 6 carbon atoms represented by may be straight-chain, branched or cyclic, and specific examples thereof include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl and n-hexyl; and cyclic saturated hydrocarbon groups having 3 to 6 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. 301 The saturated hydrocarbon group of the saturated hydrocarbonoxy group having 1 to 6 carbon atoms represented by the formula (R) may be the same as the specific examples of the saturated hydrocarbon group described above. 301 The saturated hydrocarbon group part of the saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms represented by the above-mentioned specific examples of the saturated hydrocarbon group having 1 to 6 carbon atoms include those having 1 to 5 carbon atoms.

[0856] R 301D The unsaturated aliphatic hydrocarbon group having 2 to 8 carbon atoms represented may be straight-chain, branched or cyclic, and specific examples thereof include alkenyl groups having 2 to 8 carbon atoms such as ethenyl, propenyl, butenyl and hexenyl; alkynyl groups having 2 to 8 carbon atoms such as ethynyl, propynyl and butynyl; and cyclic unsaturated aliphatic hydrocarbon groups having 3 to 8 carbon atoms such as cyclohexenyl and norbornyl.

[0857] In formula (F1), R 302 It is a saturated alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 20 carbon atoms, and a part or all of the hydrogen atoms of the saturated alkylene group may be substituted by halogen atoms other than fluorine atoms, and a part or all of the hydrogen atoms of the arylene group may be substituted by a substituent selected from a saturated alkyl group having 1 to 20 carbon atoms, a saturated alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogen atom and a hydroxyl group.

[0858] R 302 The alkylene group having 1 to 20 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. D The alkylene groups having 1 to 20 carbon atoms shown in the above-mentioned examples are the same as those exemplified above.

[0859] R 302Specific examples of the arylene group having 6 to 20 carbon atoms include phenylene, naphthylene, phenanthrenediyl, anthracenediyl, etc. The hydrocarbon radical of the saturated hydrocarbon group having 1 to 20 carbon atoms and the hydrocarbonoxy group having 1 to 20 carbon atoms of the substituent of the arylene group may be straight chain, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecanyl, tridecyl, tetradecyl, pentadecyl, heptadecanyl, octadecyl, nonadecanyl, eicosyl, etc.; and cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl. Specific examples of the arylene group having 6 to 14 carbon atoms as the substituent of the arylene group include phenylene, naphthylene, phenanthrenediyl, anthracenediyl and the like.

[0860] The anion represented by the formula (F1) is preferably an anion represented by the following formula (F2).

[0861] [Chemistry 271]

[0862]

[0863] In formula (F2), x, y, z, L 21 , L D and R 301 Same as above. m2 is an integer from 1 to 4. 302A is a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbonoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, a halogen atom or a hydroxyl group. When m2 is 2, 3 or 4, each R 302A They may be the same as or different from each other.

[0864] Specific examples of the anion represented by formula (F1) include the following, but are not limited to these.

[0865] [Chemistry 272]

[0866]

[0867] [Chemistry 273]

[0868]

[0869] [Chemistry 274]

[0870]

[0871] [Chemistry 275]

[0872]

[0873] [Chemistry 276]

[0874]

[0875] [Chemistry 277]

[0876]

[0877] [Chemistry 278]

[0878]

[0879] [Chemistry 279]

[0880]

[0881] [Chemistry 280]

[0882]

[0883] [Chemistry 281]

[0884]

[0885] [Chemistry 282]

[0886]

[0887] [Chemistry 283]

[0888]

[0889] [Chemistry 284]

[0890]

[0891] [Chemistry 285]

[0892]

[0893] [Chemistry 286]

[0894]

[0895] [Chemistry 287]

[0896]

[0897] [Chemistry 288]

[0898]

[0899] [Chemistry 289]

[0900]

[0901] [Chemistry 290]

[0902]

[0903] [Chemistry 291]

[0904]

[0905] [Chemistry 292]

[0906]

[0907] [Chemistry 293]

[0908]

[0909] [Chemistry 294]

[0910]

[0911] [Chemistry 295]

[0912]

[0913] [Chemistry 296]

[0914]

[0915] [Chemistry 297]

[0916]

[0917] [Chemistry 298]

[0918]

[0919] [Chemistry 299]

[0920]

[0921] [Chemistry 300]

[0922]

[0923] [Chemistry 301]

[0924]

[0925] [Chemistry 302]

[0926]

[0927] [Chemistry 303]

[0928]

[0929] [Chemistry 304]

[0930]

[0931] [Chemistry 305]

[0932]

[0933] [Chemistry 306]

[0934]

[0935] [Chemistry 307]

[0936]

[0937] [Chemistry 308]

[0938]

[0939] (F) In other photoacid generators, the cation that forms a pair with the anion is preferably a sulfonium cation or an iodonium cation. Specific examples of the sulfonium cation are the same as those exemplified for the sulfonium cation represented by formula (cation-1), but are not limited thereto. Specific examples of the iodonium cation are the same as those exemplified for the sulfonium cation represented by formula (cation-2), but are not limited thereto.

[0940] The acid generated by the aforementioned other photoacid generator preferably has a pKa of -2.0 or more, more preferably -1.0 or more. The upper limit of the pKa is preferably 2.0. The pKa value is calculated using the pKa database of the software ACD / Chemsketch ver: 9.04 manufactured by Advanced Chemistry Development, Inc.

[0941] When the chemically amplified positive resist composition of the present invention contains (F) other photoacid generators, the content thereof is preferably 1 to 10 parts by mass, more preferably 1 to 5 parts by mass, relative to 80 parts by mass of the base polymer. By containing other photoacid generators, the amount of acid generated in the exposed part and the dissolution resistance of the unexposed part can be appropriately adjusted. (F) Other photoacid generators can be used alone or in combination of two or more.

[0942] The chemically amplified positive resist composition of the present invention preferably contains, in addition to (A) a photoacid generator, a polymer-bonded photoacid generator containing repeating units represented by formulas (B6) to (B9) or (F) another photoacid generator. This allows the deprotection reaction of the base polymer in the resist film to proceed sufficiently, resulting in a good pattern shape and improved resolution.

[0943] [(G) Surfactant]

[0944] The chemically amplified positive resist composition of the present invention may also contain a conventional surfactant as component (G) in order to improve the coating properties on the substrate. The aforementioned surfactant is described in International Publication No. 2006 / 121096, Japanese Patent Publication No. 2008-102383, Japanese Patent Publication No. 2008-304590, Japanese Patent Publication No. 2004-115630, and Japanese Patent Publication No. 2005-8766. There are a plurality of known surfactants, and the surfactants may be selected with reference to them.

[0945] When the chemically amplified positive resist composition of the present invention contains (G) a surfactant, its content is preferably 2 parts by mass or less, more preferably 1 part by mass or less, with a lower limit of 0.01 parts by mass or more, relative to 80 parts by mass of the (B) base polymer. The (G) surfactant may be used alone or in combination of two or more.

[0946] [Resist pattern forming method]

[0947] The resist pattern forming method of the present invention comprises the following steps: a step of forming a resist film on a substrate using the aforementioned chemically amplified positive resist composition, a step of exposing the aforementioned resist film using high-energy rays, and a step of developing the aforementioned irradiated patterned resist film using an alkaline developer to obtain a resist pattern.

[0948] The aforementioned substrate may be, for example, a substrate for integrated circuit manufacturing (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, Si, SiO, SiO2, etc.). The aforementioned chemically amplified positive resist composition is applied to the aforementioned substrate by spin coating or the like to make the film thickness 0.03 to 2 μm, and is pre-baked on a hot plate, preferably at 60 to 150° C. for 1 to 20 minutes, more preferably at 80 to 140° C. for 1 to 10 minutes, to form a resist film.

[0949] The resist film is then exposed to a pattern using high-energy radiation, such as ultraviolet radiation, extreme ultraviolet radiation, excimer laser (KrF, ArF, etc.), EB, EUV, X-rays, gamma rays, synchrotron radiation, and the like.

[0950] When ultraviolet rays, extreme ultraviolet rays, excimer lasers, EUV, X-rays, gamma rays, or synchrotron radiation are used as the high-energy rays, a mask for forming a target pattern is used, and the exposure amount is preferably 1 to 300 mJ / cm 2 , preferably 10 to 200 mJ / cm 2When EB is used as high energy radiation, the exposure amount is preferably 1 to 300 μC / cm 2 , preferably 10 to 200 μC / cm 2 Furthermore, the chemically amplified positive resist composition of the present invention is particularly useful in EUV or EB lithography.

[0951] Exposure can be performed by a conventional exposure method or, if necessary, by an immersion method in which a liquid is inserted between the mask and the resist film. In this case, a water-insoluble protective film can also be used.

[0952] Then, a post-exposure bake (PEB) is performed on a hot plate, preferably at 60 to 150° C. for 1 to 20 minutes, more preferably at 80 to 140° C. for 1 to 10 minutes.

[0953] Afterwards, it is preferred to use a developer containing an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) at a concentration of 0.1 to 5% by mass, more preferably 2 to 3% by mass, and develop for 0.1 to 3 minutes, preferably 0.5 to 2 minutes, using conventional methods such as dipping, puddle, and spraying to form a desired pattern on the substrate.

[0954] The chemically amplified positive resist composition of the present invention has particularly high etching resistance, and even when the time from exposure to PEB is prolonged, the change in pattern line width is still small, and is useful when used under conditions requiring a small LER. In addition, the resist composition of the present invention is particularly useful for substrates with materials on the surface of which it is difficult to obtain adhesion with the resist pattern, and thus pattern peeling and pattern collapse are prone to occur. Such substrates include, for example, metal chromium, substrates formed by sputtering of chromium compounds containing one or more light elements selected from oxygen, nitrogen and carbon, etc. The chemically amplified positive resist composition of the present invention is particularly useful when pattern formation is performed using a blank photomask as a substrate.

[0955] [Example]

[0956] The present invention is specifically described below with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples. The apparatus used is as follows.

[0957] IR: NICOLET 6700 manufactured by Thermofisher Scientific

[0958] · 1 H-NMR: ECA-500 manufactured by JEOL Ltd.

[0959] ·MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0960] [1] Synthesis of onium salts

[0961] [Example 1-1] Synthesis of PAG-1

[0962] [Chemistry 309]

[0963]

[0964] (1) Synthesis of intermediate In-1

[0965] Under nitrogen environment, in a reaction container, 3,5-diiodosalicylic acid (195.0g), potassium carbonate (105.9g) and sodium iodide (7.5g) are suspended in DMF (1000g). The temperature in the reaction container is raised to 50°C, and 1-bromooctane (212.4g) is added dropwise. After the addition, the temperature in the reaction container is 75°C for 12 hours. After maturation, the reaction solution is cooled and water (1000g) is added to stop the reaction. The target product is extracted with a solution composed of hexane (1000g) and toluene (250g), and the usual aqueous work-up is performed. The solvent is distilled off to obtain 306.3g of intermediate In-1 as an oil (yield 100%). Intermediate In-1 is used in the next step without further purification.

[0966] (2) Synthesis of intermediate In-2

[0967] Under nitrogen environment, the intermediate In-1 (306.3 g) was dissolved in THF (700 g) in a reaction vessel. The temperature in the reaction vessel was raised to 50°C, and a 25% by mass aqueous solution of sodium hydroxide (120.0 g) was added dropwise. After the addition, the mixture was heated to reflux and matured at a temperature of 70°C in the reaction vessel for 12 hours. After maturation, the reaction solution was cooled, hexane (1000 g) was added, and the sodium salt of the target was extracted twice with water (1000 g). 20% by mass hydrochloric acid (145.5 g) was added to the aqueous layer after extraction, and the pH was confirmed to be acidic. The target was extracted with ethyl acetate (2000 g), and the usual aqueous work-up was performed. After the solvent was distilled off, it was recrystallized with hexane to obtain 162.3 g of colorless white crystals of the intermediate In-2 (yield 65%).

[0968] (3) Synthesis of intermediate In-3

[0969] Under nitrogen environment, the intermediate In-2 (20.1g) and DMF (0.03g) are dissolved in dichloromethane (100g) in a reaction container. Then, oxalyl chloride (6.1g) is added dropwise at room temperature. After the addition, the temperature in the reaction container is raised to 40°C, and the acyl chloride is prepared by aging for 4 hours. After aging, the reaction solution is distilled off to obtain 23.6g of acyl chloride. After that, the acyl chloride (23.6g), SM-2 (13.7g), and 4-dimethylaminopyridine (0.5g) are suspended in dichloromethane (80g). The temperature in the reaction container is cooled to 5°C, and a solution consisting of triethylamine (5.3g) and dichloromethane (20g) is added dropwise. After the addition, the temperature in the reaction container is raised to 25°C, and the aging is carried out for 12 hours. After aging, the reaction solution is cooled, saturated sodium bicarbonate water (50g) is added, and the reaction is stopped. Thereafter, a conventional aqueous work-up was performed and the solvent was distilled off to obtain 27.9 g of an oily intermediate In-3 (yield 88%).

[0970] (4) Synthesis of onium salt PAG-1

[0971] In a nitrogen atmosphere, the intermediate In-3 (13.5 g), the raw material SM-3 (5.8 g), dichloromethane (80 g) and water (80 g) were added to the reaction vessel, stirred for 30 minutes, and the organic layer was separated and washed with water, and then concentrated under reduced pressure. Diisopropyl ether was added to the concentrate, and the residue was washed to obtain 15.4 g of the target PAG-1 as an oil (yield 98%).

[0972] The IR spectrum data and TOF-MS results of PAG-1 are shown below. 1 The results of H-NMR / DMSO-d6) are as follows Figure 1 shown.

[0973] IR(D-ATR): ν=3061,3023,2954,2926,2869,2855,1742,1711,1593,1583,1465,1440,1368,1272 ,1238,1189,1132,1103,1064,1032,1011,997,968,885,765,705,681,642,594,551,523,487cm -1

[0974] MALDI TOF-MS: POSITIVE M + 277(C 18 H 13 OS + quite)

[0975] NEGATIVE M- 645(C 17 H 21 F2I2O6S - quite)

[0976] [Examples 1-2 to 1-10] Synthesis of PAG-2 to PAG-10

[0977] Onium salts PAG-2 to PAG-7 represented by the following formulae were synthesized using corresponding raw materials and known organic synthesis reactions.

[0978] [Chemistry 310]

[0979]

[0980] [Chemistry 311]

[0981]

[0982] The IR spectrum data and TOF-MS results of PAG-2 are shown below. 1 The results of H-NMR / DMSO-d6) are as follows Figure 2 shown.

[0983] IR(D-ATR): ν=3061,2956,2927,2870,1742,1712,1589,1565,1538,1491,1477,1465,1446,1367,125 6,1240,1189,1103,1085,1032,1010,998,968,877,839,789,751,685,642,593,551,523,505,475cm -1

[0984] MALDI TOF-MS: POSITIVE M + 319(C 22 H 23 S + quite)

[0985] NEGATIVE M - 645(C 17 H 21 F2I2O6S - quite)

[0986] The IR spectrum data and TOF-MS results of PAG-3 are shown below. 1 The results of H-NMR / DMSO-d6) are as follows Figure 3 shown.

[0987] IR(D-ATR): ν=3063,2927,2855,1732,1633,1593,1582,1534,1465,1440,1372,1270,116 2,1113,1065,1032,1015,997,972,905,886,816,763,706,681,644,590,551,523,488cm -1

[0988] MALDI TOF-MS: POSITIVE M + 277(C 18 H 13 OS + quite)

[0989] NEGATIVE M - 645(C 17 H 21 F2I2O6S - quite)

[0990] [2] Synthesis of base polymer

[0991] [Synthesis Example] Synthesis of base polymers (P-1 to P-6)

[0992] The monomers were combined according to a known formula, copolymerized in a solvent, the reaction solution was added to hexane, the precipitated solid was washed with hexane, isolated and dried, and the base polymers (P-1 to P-6) with the following compositions were obtained. 1 H-NMR, 13 The product was confirmed by C-NMR, and Mw and Mw / Mn were confirmed by GPC (solvent: THF, standard: polystyrene).

[0993] [Chemistry 312]

[0994]

[0995] [Chemistry 313]

[0996]

[0997] [3] Preparation of chemically amplified positive resist composition

[0998] [Examples 2-1 to 2-50, Comparative Examples 1-1 to 1-31]

[0999] The components were dissolved in an organic solvent according to the compositions shown in Tables 1 to 3, and the obtained solution was filtered through a nylon filter with a size of 5 nm and a UPE filter with a size of 1 nm to prepare a chemically amplified positive resist composition. The organic solvent was a mixed solvent of 940 parts by mass of PGMEA, 1870 parts by mass of EL, and 1870 parts by mass of PGME.

[1000] [Table 1]

[1001]

[1002] [Table 2]

[1003]

[1004] [Table 3]

[1005]

[1006] In Tables 1 to 3, comparative photoacid generators cPAG-1 to cPAG-6, quenchers Q-1 to Q-4, and fluorine-containing polymers D-1 to D-5 are shown below.

[1007] [Chemistry 314]

[1008]

[1009] [Chemistry 315]

[1010]

[1011] [Chemistry 316]

[1012]

[1013] [4]EB Lithography Evaluation

[1014] [Examples 3-1 to 3-50, Comparative Examples 2-1 to 2-31]

[1015] Each chemically amplified positive resist composition (R-1 to R-50, CR-1 to CR-31) was spin-coated using ACT-M (manufactured by Tokyo Electron Co., Ltd.) on a 6-inch low thermal expansion glass substrate as a reflective blank for EUV exposure mask, on which a 284nm thick Mo / Si40-layer multilayer reflective film, a 3.5nm thick Ru film as a protective film, a 70nm thick TaN film as an absorption layer, and a 6nm thick CrN film as a hard mask were formed. The resist film was pre-baked on a hot plate at 110°C for 600 seconds to prepare a resist film with a film thickness of 80nm. The film thickness of the obtained resist film was measured using an optical measuring instrument Nanospec (manufactured by Nanometrics Co., Ltd.). The measurement was performed at 81 locations within the surface of the blank substrate excluding the outer edge portion within 10 mm from the outer circumference, and the average film thickness and the film thickness range were calculated.

[1016] The resist film was exposed using an electron beam exposure apparatus (EBM-5000plus manufactured by Nuflare Technology Co., Ltd., accelerating voltage 50 kV), subjected to PEB at 110° C. for 600 seconds, and developed with a 2.38 mass % TMAH aqueous solution to obtain a positive pattern.

[1017] The obtained resist pattern was evaluated in the following manner. The blank mask with pattern produced above was observed by an empty SEM (scanning electron microscope), and the exposure amount with 1:1 line and space (LS) of 200 nm and 1:1 resolution was defined as the optimum exposure amount (μC / cm 2 ), the minimum size of the exposure amount that can be resolved by 9:1 with an isolated spacing of 200 nm was defined as the resolution (limit IS resolution), and the LER of 200 nm LS was measured by SEM. The pattern shape was visually determined to be rectangular. The results are shown in Tables 4 to 6.

[1018] [Table 4]

[1019]

[1020] [Table 5]

[1021]

[1022] [Table 6]

[1023]

[1024] The results shown in Tables 4 to 6 show that the photoacid generator composed of the onium salt of the present invention, the chemically amplified positive resist composition using the same, and the resist pattern forming method are useful in semiconductor device manufacturing, especially in optical lithography for processing transmissive and reflective blank photomasks.

Claims

1. An onium salt represented by the following formula (1): Wherein, n1 is 0 or 1, n2 is 1, 2 or 3, n3 is 1, 2, 3 or 4, n4 is an integer of 0 to 4, but when n1=0, 2≤n2+n3+n4≤5, when n1=1, 2≤n2+n3+n4≤7, n5 is an integer of 0 to 4, R alk is an alkyl group having 6 to 18 carbon atoms or a fluorinated alkyl group having 4 to 18 carbon atoms, R alk When it is an alkyl group having 6 to 18 carbon atoms, the alkyl group has at least one linear structure having 6 or more carbon atoms, and R alk When the fluorinated alkyl group is a fluorinated alkyl group having 4 to 18 carbon atoms, the fluorinated alkyl group has at least two groups selected from -CF2- and -CF3, and a portion of the -CH2- of the alkyl group and the fluorinated alkyl group may be substituted by an ether bond or a carbonyl group, and the terminal or carbon-carbon bond thereof may contain a ring structure selected from a cyclopentane ring, a cyclohexane ring, an adamantane ring, a norbornyl ring and a benzene ring, R 1 is a halogen atom other than an iodine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, L A , L B and L C are each independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond, X L is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom, Q 1 and Q 2 are each independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, Q 3 and Q 4 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, Z + It is an onium cation.

2. The onium salt according to claim 1, represented by the following formula (1A): In the formula, n1~n5, R alk , R 1 , L A , L B , L C , X L , Q 1 , Q 2 and Z + Same as above.

3. The onium salt according to claim 2, represented by the following formula (1B): In the formula, n1~n5, R alk , R 1 , L A , L C , X L , Q 1 , Q 2 and Z + Same as above.

4. The onium salt according to claim 1, wherein Z + is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2), In the formula, R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom, and R ct1 and R ct2 They may also bond to each other and to the sulfur atom to which they are bonded to form a ring. 5 . A photoacid generator, comprising the onium salt according to claim 1 . 6 . A chemically amplified positive resist composition comprising the photoacid generator according to claim 5 .

7. The chemically amplified positive resist composition according to claim 6, further comprising a base polymer, wherein the base polymer contains a polymer that is decomposed by an acid and has increased solubility in an alkaline developer.

8. The chemically amplified positive resist composition according to claim 7, wherein: The polymer contains a repeating unit represented by the following formula (B1): In the formula, a1 is 0 or 1, a2 is an integer from 0 to 2, a3 is an integer satisfying 0≤a3≤5+2(a2)-a4, and a4 is an integer from 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R 11 is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom, A 1 It is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, wherein -CH2- of the saturated alkylene group may be substituted by -O-.

9. The chemically amplified positive resist composition according to claim 7, wherein: The polymer contains a repeating unit represented by the following formula (B2-1): In the formula, b1 is 0 or 1, b2 is an integer from 0 to 2, b3 is an integer satisfying 0≤b3≤5+2(b2)-b4, b4 is an integer from 1 to 3, b5 is 0 or 1, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R 12 is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom, A 2 is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, wherein -CH2- of the saturated alkylene group may be substituted by -O-, When b4 is 1, X is an acid-labile group. When b4 is 2 or 3, each X is independently a hydrogen atom or an acid-labile group, but at least one of them is an acid-labile group.

10. The chemically amplified positive resist composition according to claim 7, wherein: The polymer contains a repeating unit represented by the following formula (B2-2): In the formula, c1 is an integer of 0 to 2, c2 is an integer of 0 to 2, c3 is an integer of 0 to 5, and c4 is an integer of 0 to 2. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R 13 and R 14 Each independently represents a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom, R 13 With R 14 They can also bond to each other and to the carbon atoms to which they are bonded to form rings. R 15 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms, R 16 are each independently a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom, A 3 is a single bond, phenylene, naphthylene or *-C(=O)-OA 31 -, A 31 It is an aliphatic alkylene group having 1 to 20 carbon atoms which may contain a hydroxyl group, an ether bond, an ester bond or a lactone ring, or a phenylene group or a naphthylene group, and * represents an atomic bond with a carbon atom of the main chain.

11. The chemically amplified positive resist composition according to claim 7, wherein: The polymer contains at least one selected from the group consisting of a repeating unit represented by the following formula (B3), a repeating unit represented by the following formula (B4), and a repeating unit represented by the following formula (B5), In the formula, d is an integer of 0 to 6, e is an integer of 0 to 4, f1 is 0 or 1, f2 is an integer of 0 to 2, and f3 is an integer of 0 to 5. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R 17 and R 18 each independently represents a hydroxyl group, a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarboncarbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, R 19 is a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbonoxy group having 1 to 20 carbon atoms, a saturated hydrocarboncarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbonoxyalkyl group having 2 to 20 carbon atoms, a saturated hydrocarbonthioalkyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, or a cyano group. When f2 is 1 or 2, it may also be a hydroxyl group. A 4 It is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of -CH2- in the saturated alkylene group may be substituted by -O-.

12. The chemically amplified positive resist composition according to claim 7, wherein: The polymer contains at least one selected from the group consisting of a repeating unit represented by the following formula (B6), a repeating unit represented by the following formula (B7), a repeating unit represented by the following formula (B8), and a repeating unit represented by the following formula (B9). In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X 1 is a single bond or a phenylene group, X 2 for* 1 -C(=O)-OX 21 -, * 1 -C(=O)-NH-X 21 -or* 1 -OX 21 -, X 21 It is a divalent group obtained by aliphatic alkylene group having 1 to 6 carbon atoms, phenylene group or a combination thereof, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group, * 1 Indicates and X 1 The atomic bonds X 3 Each independently represents a single bond, phenylene, naphthylene or * 2 -C(=O)-OX 31 -, X 31 is an aliphatic alkylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group, the aliphatic alkylene group may also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring, * 2 represents the atomic bonds between the carbon atoms of the main chain, X 4 Each is independently a single bond, * 3 -X 41 -C(=O)-O-,* 3 -C(=O)-NH-X 41 -or* 3 -OX 41 -, X 41 is an alkylene group having 1 to 20 carbon atoms which may contain a hetero atom, * 3 Indicates and X 3 The atomic bonds X 5 Each is independently a single bond, * 4 -X 51 -C(=O)-O-,* 4 -C(=O)-NH-X 51 -or* 4 -OX 51 -, X 51 is an alkylene group having 1 to 20 carbon atoms which may contain a hetero atom, * 4 Indicates and X 4 The atomic bonds X 6 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, phenylene substituted with trifluoromethyl, * 2 -C(=O)-OX 61 -, * 2 -C(=O)-N(H)-X 61 -or* 2 -OX 61 -, X 61 is an aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group,* 2 represents the atomic bonds between the carbon atoms of the main chain, R 21 and R 22 are each independently a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and R 21 and R 22 They can also bond to each other and to the sulfur atoms to which they are bonded to form a ring. L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate bond, a carbonate bond or a carbamate bond, R 1 and Rf 2 are each independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, R 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, R 5 and Rf 6 Each independently represents a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms, but is not Rf 5 and Rf 6 At the same time, it is a hydrogen atom. M - is a non-nucleophilic counter ion, A + is an onium cation, g1 and g2 are each independently an integer of 0-3.

13. The chemically amplified positive resist composition according to claim 7, further comprising an organic solvent.

14. The chemically amplified positive resist composition according to claim 7, further comprising a fluorine atom-containing polymer, wherein the fluorine atom-containing polymer comprises at least one selected from the group consisting of a repeating unit represented by the following formula (D1), a repeating unit represented by the following formula (D2), a repeating unit represented by the following formula (D3), and a repeating unit represented by the following formula (D4), and may also comprise at least one selected from the group consisting of a repeating unit represented by the following formula (D5) and a repeating unit represented by the following formula (D6), In the formula, j1 is an integer from 1 to 3, j2 is an integer satisfying 0≤j2≤5+2(j3)-j1, j3 is 0 or 1, and k is an integer from 1 to 3. R B are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R C are each independently a hydrogen atom or a methyl group, R 101 , R 102 , R 104 and R 105 are each independently a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms, R 103 , R 106 , R 107 and R 108 are each independently a hydrogen atom, a hydrocarbon group having 1 to 15 carbon atoms, a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group, and R 103 , R 106 , R 107 and R 108 When it is a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group may be inserted between the carbon-carbon bonds. R 109 is a hydrogen atom, or a linear or branched hydrocarbon group having 1 to 5 carbon atoms which may have a heteroatom-containing group inserted between carbon-carbon bonds, R 110 It is a linear or branched hydrocarbon group having 1 to 5 carbon atoms, which may have a heteroatom-containing group inserted between carbon-carbon bonds, R 111 is a saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted by a fluorine atom, and a part of the -CH2- of the saturated hydrocarbon group may be substituted by an ester bond or an ether bond, Z 1 is a (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms, Z 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * represents an atomic bond with a carbon atom of the main chain, Z 3 is a single bond, -O-, *-C(=O)-OZ 31 -Z 32 - or *-C(=O)-NH-Z 31 -Z 32 -, Z 31 is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, Z 32 It is a single bond, an ester bond, an ether bond or a sulfonamide bond, and * represents an atomic bond with a carbon atom of the main chain.

15. The chemically amplified positive resist composition according to claim 7, further comprising a quencher. 16 . The chemically amplified positive resist composition according to claim 7 , further comprising a photoacid generator other than the photoacid generator according to claim 5 .

17. A method for forming a resist pattern, comprising the following steps: A resist film is formed on a substrate using the chemically amplified positive resist composition according to any one of claims 7 to 16, the resist film is exposed using high-energy rays, and the exposed resist film is developed using an alkaline developer to obtain a resist pattern.

18. The resist pattern forming method according to claim 17, wherein: The high-energy rays are extreme ultraviolet rays or electron beams.

19. The resist pattern forming method according to claim 17, wherein: The outermost surface of the substrate is made of a material containing chromium.

20. The resist pattern forming method according to claim 17, wherein: The substrate is a blank photomask.

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