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 present invention addresses the problem of providing: an onium salt capable of generating an acid having small diffusion; a chemically amplified positive resist composition containing the onium salt; and a method for forming a resist pattern using the resist composition. [Solution] An onium salt represented by formula (A). # 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, more fine pattern formation is required. For pattern processing below 0.2μm, chemical amplification resist compositions using acid as a catalyst are mainly used. At this time, the exposure source can use high-energy rays such as ultraviolet rays, far ultraviolet rays, and electron beams (EB). EB lithography is especially used as an ultra-fine processing technology. It is also indispensable for the processing method of blank photomasks when making photomasks for semiconductor manufacturing. The resist compositions used in such optical lithography include positive types that dissolve the exposed part to form a pattern and negative types that leave the exposed part to form a pattern. They are easy for users to choose according to the form of the necessary resist pattern.

[0003] Generally speaking, the depiction by EB does not use a mask. If it is a positive type, a method is adopted in which the EB of a small area is sequentially irradiated to the parts other than the area where the resist film is to be left. If it is a negative type, the area where the resist film is to be left is sequentially irradiated. This is an operation of scanning all the finely divided areas of the processing surface, so it is more time-consuming than the one-time exposure using a photomask. In order not to reduce the processing volume, the resist film is required to be highly sensitive. In addition, the depiction time is long, so it is easy to produce a difference between the initial depiction part and the later depiction part. The stability of the exposed part in a vacuum over time is an important performance requirement item. In addition, in the processing of blank photomasks, which is a particularly important application, there will be chromium compound films represented by chromium oxide formed on the photomask substrate, which have surface materials that are easy to affect the pattern shape of the chemically amplified resist film. In order to achieve high resolution and maintain the shape after etching, it is also one of the important performances to keep the pattern outline of the resist film as a rectangle regardless of the type of substrate.

[0004] The sensitivity of the resist film and the control of the pattern profile have been improved in various ways by using the selection, combination, processing conditions, etc. 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. The shape of the resist pattern obtained in the photomask processing requires that it does not change depending on the time until the post-exposure heating (PEB), but the biggest cause of the time-dependent change is the diffusion of the acid generated by the exposure. The problem of acid diffusion is not limited to the photomask processing, and it also has a significant impact on the sensitivity and resolution of the general resist composition, so many studies have been conducted.

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

[0006] In addition, Patent Document 3 records 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 in obtaining a pattern with a small line edge roughness (LER). However, depending on the structure and introduction rate of such a repeating unit, there may be cases where the base polymer to which the repeating unit that generates acid by exposure is bonded has problems with solubility in organic solvents.

[0007] In addition, although a large amount of polymers containing an aromatic skeleton having an acidic side chain, such as polyhydroxystyrene, are useful as resist compositions for KrF lithography, they exhibit large absorption for light having a wavelength of around 200 nm and are therefore not used as materials for resist compositions for ArF lithography. However, they are important materials from the viewpoint of obtaining high etching resistance for resist compositions for EB lithography and resist compositions for extreme ultraviolet (EUV) lithography, which are powerful technologies for forming patterns smaller than the processing limit of ArF lithography.

[0008] As for the base polymer of positive EB photolithography resist composition and EUV photolithography resist composition, the acid generated by the photoacid generator by irradiation with high-energy rays is mainly used as a catalyst, and the acid-labile group (acid-decomposable protective group) of the acidic functional group of the phenol side chain possessed by the shielding base polymer is deprotected and soluble in the alkali developer. In addition, the aforementioned acid-labile group mainly uses a tertiary alkyl group, a tert-butoxycarbonyl group, an acetal group, etc. Here, if a protective group with a small activation energy required for deprotection such as an acetal group is used, although there is an advantage that a highly sensitive resist film can be obtained, if the diffusion of the generated acid is insufficient, there will be a deprotection reaction in the unexposed part of the resist film, and the problem of deterioration of LER and reduction of the in-plane uniformity (CDU) of the pattern line width is caused.

[0009] In addition, Patent Documents 4 and 5 claim a photoacid generator that generates a non-fluorinated aromatic sulfonic acid having a large number of bulky alkyl substituents. Although it is attempted to increase the molecular weight of the generated acid by utilizing a large number of alkyl substituents and thereby reduce acid diffusion, the suppression of acid diffusion is still insufficient for the purpose of fine pattern formation, leaving room for further improvement.

[0010] In addition, in the formation of fine patterns by EB lithography, the shape of the resist pattern becomes an inverse cone shape due to the influence of backscattering caused by the reflection of EB on the substrate. The inverse cone shape induces the collapse of the resist pattern during development. In order to meet the demand for further miniaturization, it is expected to solve the above-mentioned problem and develop a photoacid generator that can correct the pattern shape and 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, resist compositions with excellent hole pattern shapes are required in addition to line and space (LS), isoline (IL), and isospace (IS). The acid generator described in Patent Document 4 generates a large volume of acid and inhibits the diffusion of the acid. Although it inhibits the diffusion of the acid to a certain extent, when a fine pattern is formed, the shape of the pattern becomes an inverse cone shape, and there is a problem of pattern collapse during development caused by 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 same, and a resist pattern forming method using the resist composition.

[0021] [Methods to solve the problem]

[0022] As a result of repeated and in-depth studies to achieve the above-mentioned purpose, the inventors have obtained the following findings and have completed the present invention: when an onium salt having an aromatic sulfonic acid anion having a group containing an alkyl chain or a fluoroalkyl chain, an aromatic ring substituted with an iodine atom, and a fluorine-containing substituent is introduced into a resist composition as an acid generator, the onium salt is distributed and concentrated in the upper layer of the resist film due to the effect of the alkyl chain or the fluoroalkyl chain, and a pattern with good resolution and small CDU and LER can be obtained by utilizing the effect of correcting the pattern shape, and a pattern with good rectangularity can be obtained due to appropriate dissolution inhibition.

[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 (A).

[0025] [Chemistry 1]

[0026]

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

[0028] n5 is 0, 1 or 2. n6 is an integer of 0 to 4 when n5 is 0, an integer of 0 to 6 when n5 is 1, and an integer of 0 to 8 when n5 is 2. n7 is an integer of 0 to 4 when n5 is 0, an integer of 0 to 6 when n5 is 1, and an integer of 0 to 8 when n5 is 2. However, n6+n7 is 0 to 4 when n5 is 0, 0 to 6 when n5 is 1, and 0 to 8 when n5 is 2.

[0029] 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 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.

[0030] 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.

[0031] R 2is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when n7 is 2 or more, a plurality of R 2 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring.

[0032] R F1 is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated thioalkoxy group having 1 to 6 carbon atoms. F1 They can be the same or different.

[0033] 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.

[0034] X L It is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom.

[0035] Z + It is an onium cation.

[0036] 2. The onium salt according to 1., which is represented by the following formula (A1).

[0037] [Chemistry 2]

[0038]

[0039] In the formula, n1~n4, n6, n7, R alk , R 1 , R 2 , R F1 , L A , L B , L C , X L and Z + Same as above.

[0040] 3. The onium salt according to 2., which is represented by the following formula (A2).

[0041] [Chemistry 3]

[0042]

[0043] In the formula, n1~n4, n6, n7, R alk , R 1 , R 2 , R F1 , L A , L C , X L and Z + Same as above.

[0044] 4. The onium salt according to any one of 1. to 3., wherein Z + It is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2).

[0045] [Chemistry 4]

[0046]

[0047] 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.

[0048] 5. A photoacid generator, which is composed of the onium salt according to any one of 1. to 4.

[0049] 6. A chemically amplified positive resist composition comprising the photoacid generator of 5.

[0050] 7. The chemically amplified positive resist composition of 6. further comprises a base polymer comprising a polymer that decomposes under the action of an acid and increases its solubility in an alkaline developer.

[0051] 8. The chemically amplified positive resist composition according to 7., wherein the polymer comprises a repeating unit represented by the following formula (B1).

[0052] [Chemistry 5]

[0053]

[0054] 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.

[0055] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0056] 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 hydrocarbon oxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom.

[0057] A 1 It is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of the -CH2- of the saturated alkylene group may be substituted by -O-.

[0058] 9. The chemically amplified positive resist composition according to 7. or 8., wherein the polymer comprises a repeating unit represented by the following formula (B2).

[0059] [Chemistry 6]

[0060]

[0061] 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.

[0062] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0063] 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 hydrocarbon oxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom.

[0064] A 2 It is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of the -CH2- of the saturated alkylene group may be substituted by -O-.

[0065] 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.

[0066] 10. The chemically amplified positive resist composition according to any one of 7. to 9., wherein the polymer comprises a repeating unit represented by the following formula (B2-2).

[0067] [Chemistry 7]

[0068]

[0069] 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.

[0070] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0071] R 13 and R 14 are each independently a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom, and R 13 With R 14 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring.

[0072] R 15Each 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.

[0073] R 16 Each independently is a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom.

[0074] 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. * is an atomic bond to a carbon atom of the main chain.

[0075] 11. A chemically amplified positive resist composition as described in any one of 7. to 10., wherein the polymer contains at least one 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).

[0076] [Chemistry 8]

[0077]

[0078] 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.

[0079] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0080] R 17 and R 18 Each of them 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 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.

[0081] 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 thioalkyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, or a cyano group, and when f2 is 1 or 2, it may also be a hydroxyl group.

[0082] A 4 It is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of the -CH2- of the saturated alkylene group may be substituted by -O-.

[0083] 12. A chemically amplified positive resist composition as described in any one of 7. to 11., wherein the aforementioned polymer contains at least one 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).

[0084] [Chemistry 9]

[0085]

[0086] In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0087] X 1 It is a single bond or a phenylene group.

[0088] X 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 of atomic bonds.

[0089] X 3 are independently 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 to the carbon atoms of the main chain.

[0090] X 4 are independently single bonds, * 3 -X 41 -C(=O)-O-,* 3 -C(=O)-NH-X 41 -or* 3 -OX 41 -.X 41 It is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 3 Indicates and X 3 of atomic bonds.

[0091] X 5are independently single bonds, * 4 -X 51 -C(=O)-O-,* 4 -C(=O)-NH-X 51 -or* 4 -OX 51 -.X 51 It is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 4 Indicates and X 4 of atomic bonds.

[0092] 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 also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 2 Represents the atomic bonds to the carbon atoms of the main chain.

[0093] 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.

[0094] 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.

[0095] R 1 and Rf 2 Each independently represents a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms.

[0096] R 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.

[0097] R 5 and Rf 6 are independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 5 and Rf 6 It cannot be a hydrogen atom at the same time.

[0098] M- It is a non-nucleophilic relative ion.

[0099] A + It is an onium cation.

[0100] g1 and g2 are each independently an integer of 0-3.

[0101] 13. The chemically amplified positive resist composition according to any one of 6. to 12. further comprises an organic solvent.

[0102] 14. The chemically amplified positive resist composition as described in any one of items 6. to 13. further contains a polymer containing fluorine atoms, and the polymer containing fluorine atoms contains at least one of the repeating units represented by the following formula (D1), the repeating units represented by the following formula (D2), the repeating units represented by the following formula (D3) and the repeating units represented by the following formula (D4), and may also contain at least one of the repeating units represented by the following formula (D5) and the repeating units represented by the following formula (D6).

[0103] [Chemistry 10]

[0104]

[0105] 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.

[0106] R B are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0107] R C are each independently a hydrogen atom or a methyl group.

[0108] R 101 , R 102 , R 104 and R 105 Each independently represents a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms.

[0109] R 103 , R 106 , R 107 and R 108 are 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.

[0110] R 109It 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.

[0111] 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.

[0112] 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- group of the saturated hydrocarbon group may be substituted by an ester bond or an ether bond.

[0113] 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.

[0114] Z 2 It is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * represents an atomic bond to a carbon atom of the main chain.

[0115] 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 is a single bond, ester bond, ether bond or sulfonamide bond. * is an atomic bond to a carbon atom of the main chain.

[0116] 15. The chemically amplified positive resist composition according to any one of 6. to 14., further comprising a quencher.

[0117] 16. The chemically amplified positive resist composition according to any one of 6. to 15., further comprising a photoacid generator other than the photoacid generator according to 5.

[0118] 17. A method for forming a resist pattern, comprising the following steps:

[0119] Using the chemically amplified positive resist composition of any one of 6. to 16. to form a resist film on a substrate,

[0120] The resist film is exposed to high energy radiation, and

[0121] The exposed resist film is developed using an alkaline developer to obtain a resist pattern.

[0122] 18. The resist pattern forming method according to 17., wherein the high-energy ray is EUV or EB.

[0123] 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.

[0124] 20. The resist pattern forming method according to any one of 17. to 19., wherein the substrate is a blank photomask.

[0125] [Effects of the Invention]

[0126] The chemically amplified positive resist composition containing the onium salt of the present invention as a photoacid generator can provide a pattern with extremely high resolution and small LER in microfabrication technology, especially in EB lithography and EUV lithography. In addition, due to having appropriate dissolution resistance, a pattern with good rectangularity can be provided, so it is ideal as a chemically amplified positive resist material. BRIEF DESCRIPTION OF THE DRAWINGS

[0127] [ Figure 1 ] The nuclear magnetic resonance spectrum of the onium salt PAG-1 synthesized in Example 1-1 ( 1 H-NMR / DMSO-d6).

[0128] [ Figure 2 ] The nuclear magnetic resonance spectrum of the onium salt PAG-2 synthesized in Example 1-2 ( 1 H-NMR / DMSO-d6).

[0129] [ Figure 3 ] The nuclear magnetic resonance spectrum of the onium salt PAG-3 synthesized in Example 1-3 ( 1 H-NMR / DMSO-d6). DETAILED DESCRIPTION

[0130] The present invention will be 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 there may be mirror image isomers and non-mirror image isomers. In this case, one formula is used to represent these isomers. These isomers can be used alone or in the form of a mixture of two or more.

[0131] [Onium salt]

[0132] The onium salt of the present invention is represented by the following formula (A).

[0133] [Chemistry 11]

[0134]

[0135] In formula (A), n1 is 0 or 1. When n1 is 0, it represents a benzene ring, and when n1 is 1, it represents a naphthalene ring. From the viewpoint of solvent solubility, n1 is preferably a benzene ring of 0. n2 is 1, 2 or 3, and is preferably 1 or 2. n3 is an integer of 0 to 4, and is preferably 1, 2 or 3 from the viewpoint of solvent solubility and lithography performance. n4 is an integer of 0 to 4, and is preferably 0 or 1. However, when n1 is 0, 1≤n2+n3+n4≤5, and when n1 is 1, 1≤n2+n3+n4≤7.

[0136] In formula (A), n5 is 0, 1 or 2. When n5 is 0, it represents a benzene ring, when n5 is 1, it represents a naphthalene ring, and when n5 is 2, it represents an anthracene ring. From the viewpoint of solvent solubility and photolithography performance, it is preferably a benzene ring in which n5 is 0 or a naphthalene ring in which n5 is 1. n6 is an integer of 0 to 4 when n5 is 0, an integer of 0 to 6 when n5 is 1, and an integer of 0 to 8 when n5 is 2. n7 is an integer of 0 to 4 when n5 is 0, an integer of 0 to 6 when n5 is 1, and an integer of 0 to 8 when n5 is 2. However, n6+n7 is 0 to 4 when n5 is 0, 0 to 6 when n5 is 1, and 0 to 8 when n5 is 2.

[0137] In formula (A), R alk It is an alkyl group having 6 to 18 carbon atoms or a fluorinated alkyl group having 4 to 18 carbon atoms.

[0138] 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, decane-2-yl, decane-4-yl, octadecane-8-yl, 7,7-dimethyloctyl, 7,7-diethylnonyl, 4-butyldodecyl, etc. In addition, a part of -CH2- of the above-mentioned 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 its end or between carbon-carbon bonds, such as a cyclopentane ring, a cyclohexane ring, an adamantane ring, a norbornane ring, or a benzene ring. R alk Preferably, it is a straight-chain alkyl group or a straight-chain ethylene glycol dimethyl ether chain. alk Can be the same or different.

[0139] 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. alkSpecific 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., wherein a part or all of the hydrogen atoms are substituted with fluorine atoms. In addition, a part of the -CH2- of the above-mentioned fluorinated alkyl group may be substituted with an ether bond or a carbonyl group, and may have a ring structure at its terminal or between carbon-carbon bonds, such as a cyclopentane ring, a cyclohexane ring, an adamantane ring, a norbornyl ring, or a benzene ring.

[0140] R alk The following are preferred, but not limited thereto. In the following formula, the dotted line represents an atomic bond.

[0141] [Chemistry 12]

[0142]

[0143] In formula (A), 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.

[0144] 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, and 2-ethylhexyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6 ] cyclic aliphatic 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 thereto. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, and part of -CH2- of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and the like, and as a result, may 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, and the like.

[0145] When n4 is 2 or more, two R 1They may also be bonded to each other and form a ring together with the carbon atoms to which they are bonded. Examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. 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, or a halogen atom, 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, or a nitrogen atom, and 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, and the like may be contained.

[0146] In formula (A), R 2 is a hydrocarbon group having 1 to 20 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 and are shown as R 1 The same examples apply to the hydrocarbon groups represented by 2 They can be the same or different.

[0147] When n7 is 2 or more, multiple R 2 They may also be bonded to each other and to form a ring together with the carbon atom to which they are bonded. The aforementioned ring is preferably a 5- to 8-membered ring.

[0148] In formula (A), R F1 R is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated thioalkoxy group having 1 to 6 carbon atoms. F1 It is preferably a fluorine atom, a trifluoromethyl group, a difluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, a trifluoromethylthio group or a difluoromethylthio group, and is more preferably a fluorine atom, a trifluoromethyl group or a trifluoromethoxy group. By containing a fluorine atom, the acid strength of the generated acid is improved, so the deprotection reaction proceeds smoothly. When n6 is 2 or more, each R F1 They can be the same or different.

[0149] In formula (A), L A , L B and L C Each of them is independently a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate 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.

[0150] In formula (A), X LIt is a single bond or a alkylene group having 1 to 40 carbon atoms which may contain 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 atoms, nitrogen atoms, sulfur atoms, etc.

[0151] X L Specific examples of the alkylene group having 1 to 40 carbon atoms which may contain a hetero atom as represented by are shown below, but are not limited thereto. A and L B of atomic bonds.

[0152] [Chemistry 13]

[0153]

[0154] [Chemistry 14]

[0155]

[0156] [Chemistry 15]

[0157]

[0158] [Chemistry 16]

[0159]

[0160] Among them, X L -0~X L -22 and X L -47~X L -58.

[0161] The onium salt represented by the formula (A) is preferably represented by the following formula (A1).

[0162] [Chemistry 17]

[0163]

[0164] In the formula, n1~n4, n6, n7, R alk , R 1 , R 2 , R F1 , L A , L B , L C , X L and Z + Same as above.

[0165] The onium salt represented by the formula (A1) is preferably represented by the following formula (A2).

[0166] [Chemistry 18]

[0167]

[0168] In the formula, n1~n4, n6, n7, R alk , R 1 , R 2 , R F1 , L A , L C , X L and Z + Same as above.

[0169] Particularly preferred examples of the anion of the onium salt represented by the formula (A) include the following, but are not limited thereto. In the following formula, Me is a methyl group.

[0170] [Chemistry 19]

[0171]

[0172] [Chemistry 20]

[0173]

[0174] [Chemistry 21]

[0175]

[0176] [Chemistry 22]

[0177]

[0178] [Chemistry 23]

[0179]

[0180] [Chemistry 24]

[0181]

[0182] [Chemistry 25]

[0183]

[0184] [Chemistry 26]

[0185]

[0186] [Chemistry 27]

[0187]

[0188] [Chemistry 28]

[0189]

[0190] [Chemistry 29]

[0191]

[0192] [Chemistry 30]

[0193]

[0194] [Chemistry 31]

[0195]

[0196] [Chemistry 32]

[0197]

[0198] [Chemistry 33]

[0199]

[0200] [Chemistry 34]

[0201]

[0202] [Chemistry 35]

[0203]

[0204] [Chemistry 36]

[0205]

[0206] [Chemistry 37]

[0207]

[0208] [Chemistry 38]

[0209]

[0210] [Chemistry 39]

[0211]

[0212] [Chemistry 40]

[0213]

[0214] [Chemistry 41]

[0215]

[0216] [Chemistry 42]

[0217]

[0218] [Chemistry 43]

[0219]

[0220] [Chemistry 44]

[0221]

[0222] [Chemistry 45]

[0223]

[0224] [Chemistry 46]

[0225]

[0226] [Chemistry 47]

[0227]

[0228] [Chemistry 48]

[0229]

[0230] [Chemistry 49]

[0231]

[0232] [Chemistry 50]

[0233]

[0234] [Chemistry 51]

[0235]

[0236] [Chemistry 52]

[0237]

[0238] [Chemistry 53]

[0239]

[0240] [Chemistry 54]

[0241]

[0242] [Chemistry 55]

[0243]

[0244] [Chemistry 56]

[0245]

[0246] [Chemistry 57]

[0247]

[0248] [Chemistry 58]

[0249]

[0250] [Chemistry 59]

[0251]

[0252] [Chemistry 60]

[0253]

[0254] [Chemistry 61]

[0255]

[0256] [Chemistry 62]

[0257]

[0258] [Chemistry 63]

[0259]

[0260] [Chemistry 64]

[0261]

[0262] [Chemistry 65]

[0263]

[0264] [Chemistry 66]

[0265]

[0266] [Chemistry 67]

[0267]

[0268] [Chemistry 68]

[0269]

[0270] [Chemistry 69]

[0271]

[0272] [Chemistry 70]

[0273]

[0274] [Chemistry 71]

[0275]

[0276] [Chemistry 72]

[0277]

[0278] [Chemistry 73]

[0279]

[0280] [Chemistry 74]

[0281]

[0282] [Chemistry 75]

[0283]

[0284] [Chemistry 76]

[0285]

[0286] [Chemistry 77]

[0287]

[0288] [Chemistry 78]

[0289]

[0290] [Chemistry 79]

[0291]

[0292] [Chemistry 80]

[0293]

[0294] [Chemistry 81]

[0295]

[0296] [Chemistry 82]

[0297]

[0298] [Chemistry 83]

[0299]

[0300] [Chemistry 84]

[0301]

[0302] [Chemistry 85]

[0303]

[0304] [Chemistry 86]

[0305]

[0306] [Chemistry 87]

[0307]

[0308] [Chemistry 88]

[0309]

[0310] [Chemistry 89]

[0311]

[0312] [Chemistry 90]

[0313]

[0314] [Chemistry 91]

[0315]

[0316] [Chemistry 92]

[0317]

[0318] [Chemistry 93]

[0319]

[0320] [Chemistry 94]

[0321]

[0322] [Chemistry 95]

[0323]

[0324] [Chemistry 96]

[0325]

[0326] [Chemistry 97]

[0327]

[0328] [Chemistry 98]

[0329]

[0330] [Chemistry 99]

[0331]

[0332] [Chemical 100]

[0333]

[0334] [Chemistry 101]

[0335]

[0336] [Chemistry 102]

[0337]

[0338] [Chemistry 103]

[0339]

[0340] [Chemistry 104]

[0341]

[0342] [Chemistry 105]

[0343]

[0344] [Chemistry 106]

[0345]

[0346] [Chemistry 107]

[0347]

[0348] [Chemistry 108]

[0349]

[0350] [Chemistry 109]

[0351]

[0352] [Chemistry 110]

[0353]

[0354] [Chemistry 111]

[0355]

[0356] [Chemistry 112]

[0357]

[0358] [Chemistry 113]

[0359]

[0360] [Chemistry 114]

[0361]

[0362] [Chemistry 115]

[0363]

[0364] [Chemistry 116]

[0365]

[0366] [Chemistry 117]

[0367]

[0368] [Chemistry 118]

[0369]

[0370] [Chemistry 119]

[0371]

[0372] In formula (A), 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).

[0373] [Chemistry 120]

[0374]

[0375] 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.

[0376] 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.

[0377] 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; groups obtained by combining these groups, but aryl groups are preferred. Furthermore, 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, and halogen atoms, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain hydroxyl groups, cyano groups, nitro 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, and the like.

[0378] 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.

[0379] [Chemistry 121]

[0380]

[0381] In the formula, the dotted line represents and R ct3 of atomic bonds.

[0382] Examples of the sulfonium cation represented by the formula (cation-1) include the following, but are not limited thereto.

[0383] [Chemistry 122]

[0384]

[0385] [Chemistry 123]

[0386]

[0387] [Chemistry 124]

[0388]

[0389] [Chemistry 125]

[0390]

[0391] [Chemistry 126]

[0392]

[0393] [Chemistry 127]

[0394]

[0395] [Chemistry 128]

[0396]

[0397] [Chemistry 129]

[0398]

[0399] [Chemistry 130]

[0400]

[0401] [Chemistry 131]

[0402]

[0403] [Chemistry 132]

[0404]

[0405] [Chemistry 133]

[0406]

[0407] [Chemistry 134]

[0408]

[0409] [Chemistry 135]

[0410]

[0411] [Chemistry 136]

[0412]

[0413] [Chemistry 137]

[0414]

[0415] [Chemistry 138]

[0416]

[0417] [Chemistry 139]

[0418]

[0419] [Chemistry 140]

[0420]

[0421] [Chemistry 141]

[0422]

[0423] [Chemistry 142]

[0424]

[0425] [Chemistry 143]

[0426]

[0427] [Chemistry 144]

[0428]

[0429] [Chemistry 145]

[0430]

[0431] [Chemistry 146]

[0432]

[0433] [Chemistry 147]

[0434]

[0435] [Chemistry 148]

[0436]

[0437] Examples of the iodonium cation represented by the formula (cation-2) include the following, but are not limited thereto.

[0438] [Chemistry 149]

[0439]

[0440] [Chemistry 150]

[0441]

[0442] Specific examples of the onium salt of the present invention include any combination of the above-mentioned anions and cations.

[0443] The onium salt of the present invention can be synthesized by a known method. As an example, a method for producing an onium salt represented by the following formula (PAG-1-ex) will be described.

[0444] [Chemistry 151]

[0445]

[0446] In the formula, n1~n7, R alk , R 1 , R 2 , R F1 , L A , X L and Z + Same as above. X Hal is a chlorine atom, a bromine atom or an iodine atom. X Together with the adjacent -CO2-, it forms a primary or secondary ester group. + For the cation. - For the anion.

[0447] The first step is a step of reacting a phenol compound (SM-1) which is commercially available or can be synthesized by a known synthesis method with a haloalkyl compound (SM-2), and obtaining an intermediate In-1-ex. 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 then a base is added, and the raw material SM-2 is added dropwise to carry out the reaction. The base used can be listed 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 be heated as needed. The reaction temperature is carried out from room temperature to about the boiling point of the solvent used. If it is carried out under heating conditions, it is ideal for the reaction to proceed smoothly. In addition, the reaction can be accelerated by adding an alkali metal iodide as a catalyst. As examples, sodium iodide and potassium iodide can be listed. The reaction time is ideal from the viewpoint of yield, if the reaction is tracked by silica gel thin layer chromatography (TLC) and the reaction is completed, usually about 4 to 12 hours. Thereafter, the reaction is stopped with water, and the target 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.

[0448] The second step is to convert the -CO2-R xThe first or second ester bond of the reaction mixture is hydrolyzed 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 to carry out the hydrolysis. 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. If it is carried out under heating conditions, it is ideal for the reaction to proceed smoothly. The reaction time is ideal from the perspective of yield if the reaction is tracked by TLC and the reaction is completed, usually about 4 to 12 hours. Thereafter, the reaction is stopped using dilute hydrochloric acid or the like, and the pH is adjusted to acidic. At this point, the target substance is extracted from the reaction mixture, and a conventional aqueous work-up is performed to obtain the intermediate In-2-ex. If necessary, the intermediate In-2-ex obtained can be purified by conventional methods such as chromatography and recrystallization.

[0449] 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 carboxyl group of the intermediate In-2-ex and the hydroxyl group of the raw material SM-3 directly form an ester bond, various condensing agents can be used. The condensing agents used can be listed as: N, N'-dicyclohexylcarbodiimide, N, N'-diisopropylcarbodiimide, 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, etc. Considering the easy removal of the urea compound generated as a by-product after the reaction, it is preferable to use 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. 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 improved. The reaction time is ideal from the perspective of yield if the reaction is tracked by TLC and the reaction is completed, usually about 12 to 24 hours. After the reaction is stopped, the by-product urea compound is filtered or washed with water as needed, and the reaction solution is subjected to a conventional aqueous work-up to obtain the intermediate In-3-ex. Alternatively, the intermediate In-2-ex can be obtained by using oxalyl chloride or thionyl chloride to prepare an acyl chloride, and then reacting it with the raw material SM-3 to obtain the intermediate In-3-ex. During the reaction, a base such as triethylamine, diisopropylethylamine, pyridine, and 2,6-dimethylpyridine is preferably used. In addition, in order to accelerate the reaction, it is ideal 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.

[0450] The fourth step is to react the obtained intermediate In-3-ex with Z + X - The step of performing salt exchange with the onium salt represented by X to obtain the onium salt PAG-1-ex. - Chloride ion, bromide ion, iodide ion or methylsulfate anion is preferred from the viewpoint that the exchange reaction is easy to proceed quantitatively. It is preferred from the viewpoint of yield to confirm the progress of the reaction by TLC. The onium salt PAG-1-ex can be obtained by subjecting the reaction mixture to a conventional aqueous work-up. If necessary, purification can be carried out by conventional methods such as chromatography and recrystallization.

[0451] In the above process, 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.

[0452] In addition, the above-mentioned production method is only an example at best, and the production method of the onium salt of the present invention is not limited to this.

[0453] The onium salt represented by formula (A) is characterized in that it contains a group containing an alkyl chain or a fluoroalkyl chain on the aromatic ring of the anion. It is believed that the aforementioned alkyl chain or fluoroalkyl chain acts as a hydrophobic group, so the aforementioned onium salt will be distributed and concentrated on the surface layer in the resist film. Especially in alkali-developed positive EB lithography, due to the backscattering caused between the EB and the substrate, the pattern shape will become an inverse cone shape, and the collapse of the pattern after development caused by this will become a problem. By using the onium salt of the present invention, even in the upper part of the pattern, the deprotection reaction of the base polymer will still be effectively carried out, so it can be corrected to a rectangular pattern. In addition, the onium salt of the present invention preferably has an iodine atom in the anion, and the iodine atom on the aromatic ring can also improve the sensitivity in EB lithography while also having appropriate dissolution inhibition. It is believed that by virtue of these synergistic effects, when using a resist composition containing the onium salt of the present invention, a pattern with good resolution, high contrast, small CDU and LER can be obtained, and a pattern with good rectangularity can be obtained due to appropriate dissolution inhibition. In addition, the onium salt of the present invention has sufficient fat solubility, so it is easy to manufacture and handle.

[0454] The onium salt of the present invention can be preferably used as a photoacid generator.

[0455] [Chemically amplified positive resist composition]

[0456] [(A) Photoacid generator]

[0457] The chemically amplified positive resist composition of the present invention contains, as the component (A), a photoacid generator composed of an onium salt represented by the formula (A) as an essential component.

[0458] 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, the amount of acid required 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.

[0459] [(B) Base polymer]

[0460] The resist composition of the present invention contains, as the component (B), a base polymer comprising a polymer that is decomposed by the action of an acid and increases in solubility in an alkaline developer.

[0461] The polymer is preferably a polymer containing a repeating unit represented by the following formula (B1) (hereinafter also referred to as repeating unit B1).

[0462] [Chemistry 152]

[0463]

[0464] 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 preferable 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 preferable that a3 is an integer of 0 to 4 and a4 is an integer of 1 to 3.

[0465] In formula (B1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0466] 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 hydrocarbon oxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom. The aforementioned saturated hydrocarbon group, as well as the saturated hydrocarbon radical of the saturated hydrocarbon carbonyloxy group and the saturated hydrocarbon oxy 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 can be the same or different.

[0467] 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 inserted 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 inserted 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. In addition, if the carbon number of the saturated alkylene group is 10 or less, sufficient solubility in an alkaline developer can be obtained, which is more preferable.

[0468] a1 is 0 and A 1 When it is a single bond, that is, 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 exemplified, but the present invention is not limited thereto.

[0469] [Chemistry 153]

[0470]

[0471] [Chemistry 154]

[0472]

[0473] [Chemistry 155]

[0474]

[0475] a1 is 1 (i.e., has -C(=O)-OA 1 - as a linking group), the following are preferred examples of repeating unit B1, but are not limited thereto. A Same as above.

[0476] [Chemistry 156]

[0477]

[0478] [Chemistry 157]

[0479]

[0480] [Chemistry 158]

[0481]

[0482] [Chemistry 159]

[0483]

[0484] The content of repeating unit B1 is preferably 15 to 90 mol %, and more preferably 15 to 80 mol % in all repeating units constituting the aforementioned polymer. However, when the polymer described later contains at least one of the repeating units represented by formula (B3) and the repeating units represented by formula (B4) that provide higher etching resistance, and the unit has a phenolic hydroxyl group as a substituent, it is also appropriate to add the ratio thereof and set it within the aforementioned range. Repeating unit B1 can be used alone or in combination of two or more.

[0485] In order to provide the property that the exposed portion of the polymer as a positive resist composition will dissolve in an alkaline developer, it is preferable that the polymer contain 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 an acid (hereinafter also referred to as repeating unit B2).

[0486] The most desirable example of the repeating unit B2 includes a unit represented by the following formula (B2-1) (hereinafter also referred to as repeating unit B2-1).

[0487] [Chemistry 160]

[0488]

[0489] 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.

[0490] In formula (B2-1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0491] 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 hydrocarbon oxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom. The aforementioned saturated hydrocarbon group, as well as the saturated hydrocarbon radical of the saturated hydrocarbon carbonyloxy group and the saturated hydrocarbon oxy group may be any of linear, branched, and 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 can be the same or different.

[0492] In formula (B2-1), A 2 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-. The saturated alkylene group may be any of linear, branched, and cyclic. 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 inserted 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 inserted 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. In addition, if the carbon number of the saturated alkylene group is 10 or less, sufficient solubility in an alkaline developer can be obtained, which is more preferable.

[0493] 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, the repeating unit B2-1 is a phenolic hydroxyl group bonded to the aromatic ring, at least one of which is protected by an acid-labile group, or a carboxyl group bonded to the aromatic ring is protected by an acid-labile group. The aforementioned acid-labile group can be used without any particular limitation if it is used in a variety of well-known chemically amplified positive resist compositions and is detached by acid and provides an acidic group.

[0494] Examples of the acid-labile group include saturated tertiary hydrocarbon groups. The saturated tertiary hydrocarbon group preferably has 4 to 18 carbon atoms in order to obtain the obtained monomer for polymerization by distillation.

[0495] 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 functional group containing an oxygen atom such as a carbonyl group, etc. between carbon-carbon bonds. Furthermore, the saturated hydrocarbon groups bonded to the tertiary carbon atom may bond to each other and form a ring together with the tertiary carbon atom to which they are bonded.

[0496] The alkyl substituents include 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 ] dodecyl, tetracyclo[4.4.0.1 2,5 .1 7,10 ] dodecyl, 3-oxo-1-cyclohexyl, and the like.

[0497] The saturated tertiary hydrocarbon group may be exemplified by 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 thereto.

[0498] In addition, the acid-labile group may be 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 stably provides a pattern with a relatively rectangular interface between the pattern and the substrate. When X is a group represented by formula (B2-1-1), an acetal structure is formed.

[0499] [Chemistry 161]

[0500]

[0501] In the formula, the dotted lines represent atomic bonds.

[0502] 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.

[0503] R L1 The group should be appropriately selected according to the sensitivity of the acid-degradable group. For example, if the group is designed to be decomposed by strong acid while ensuring high stability, a hydrogen atom or a group in which the carbon atom bonded to the acetal carbon is a tertiary carbon atom is preferably selected. L1 Examples of R include, but are not limited to, tert-butyl, tert-amyl, and 1-adamantyl. If the design is to use a higher reactivity to provide high sensitivity to pH changes, a straight-chain alkyl group is preferred. Although it also depends on the combination of the acid generator and quencher added to the resist composition, R L2 For example, when a larger 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 isopropyl, sec-butyl, cyclopentyl, cyclohexyl, etc., but are not limited thereto.

[0504] In formula (B2-1-1), R L2 The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. A portion of the -CH2- of the hydrocarbon group may be substituted by heteroatoms such as oxygen atoms and sulfur atoms, and may contain ether bonds, thioether bonds, etc. 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. L2In the case of a hydrocarbon group having 1 to 6 carbon atoms, the alcohol generated by the deprotection reaction by an acid is water-soluble and thus dissolves in an alkaline developer when a positive-type pattern is formed. This can suppress residue defects in the exposed portion.

[0505] Preferred examples of the group represented by formula (B2-1-1) include the following, but are not limited thereto. L1 As before, dashed lines represent atomic bonds.

[0506] [Chemistry 162]

[0507]

[0508] [Chemistry 163]

[0509]

[0510] Other acid-labile groups may be groups in which the hydrogen atom of a phenolic hydroxyl group is replaced by -CH2COO- (a saturated tertiary hydrocarbon group). In this case, the saturated tertiary hydrocarbon group may be the same as the saturated tertiary hydrocarbon group used for the protection of the phenolic hydroxyl group.

[0511] 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 dissolution rate of the repeating unit B2-2 in the exposed part becomes high, so it is a useful option as a unit containing an acid-labile group that provides good performance for line width variation under development load.

[0512] [Chemistry 164]

[0513]

[0514] 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.

[0515] In formula (B2-2), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0516] In formula (B2-2), R 13 and R 14 are each independently a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom, and R 13 With R 14 They may also bond to each other and to the carbon atoms to which they are bonded to form a ring.

[0517] 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.

[0518] In formula (B2-2), R 16 Each independently is a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom.

[0519] 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.

[0520] Preferred examples of repeating unit B2-2 include those shown below, but are not limited thereto. A Same as above.

[0521] [Chemistry 165]

[0522]

[0523] [Chemistry 166]

[0524]

[0525] 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 above-mentioned polymer. The repeating unit B2 may be used alone or in combination of two or more.

[0526] 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).

[0527] [Chemistry 167]

[0528]

[0529] In formulae (B3) and (B4), d is an integer of 0-6. e is an integer of 0-4.

[0530] In formula (B3) and (B4), R 17 and R 18 Each of R 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 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 17They may be the same or different from each other. When e is 2 or more, each R 18 They can be the same or different.

[0531] 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.

[0532] In formula (B5), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0533] 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 carbonyl oxy group having 2 to 20 carbon atoms, a saturated hydrocarbon oxy hydrocarbon group having 2 to 20 carbon atoms, a saturated hydrocarbon thio hydrocarbon group having 2 to 20 carbon atoms, a halogen atom, a nitro group, or a cyano group, and when f2 is 1 or 2, it may be a hydroxyl group. The saturated hydrocarbon group, saturated hydrocarbon oxy group, saturated hydrocarbon carbonyl oxy group, saturated hydrocarbon oxy hydrocarbon group, and saturated hydrocarbon thio hydrocarbon group may be straight-chain, branched, or cyclic. When f3 is 2 or more, each R 19 They can be the same or different.

[0534] In formula (B5), A 4 is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a portion 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 A in formula (B1): 1 The same example as that illustrated in the description of .

[0535] 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 etching resistance and EB irradiation resistance during pattern inspection can be improved by adding a ring structure to the main chain.

[0536] In order to obtain the effect of improving etching resistance, the content of repeating units B3 to B5 is preferably 5 mol% or more in all repeating units constituting the aforementioned polymer. In addition, the content of repeating units B3 to B5 is preferably 25 mol% or less, and more preferably 20 mol% or less in all repeating units constituting the aforementioned polymer. When there is no functional group or the functional group is other than hydroxyl group, if the introduction amount is 25 mol% or less, there is no concern about the occurrence of development defects, so it is more ideal. Repeating units B3 to B5 can be used alone or in combination of two or more.

[0537] The polymer contains repeating unit B1, repeating unit B2, and at least one selected from repeating units B3 to B5, which is more desirable from the viewpoint of achieving both high etching resistance and resolution. In this case, these repeating units preferably contain 60 mol% or more, more preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more of all the repeating units in the polymer.

[0538] 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).

[0539] [Chemistry 168]

[0540]

[0541] In formulas (B6) to (B9), R A are 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 are independently 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 bond to the carbon atom of the main chain. 4 are independently single bonds, * 3 -X 41 -C(=O)-O-,* 3 -C(=O)-NH-X 41 -or* 3 -OX 41 -.X 41It is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 3 Indicates and X 3 Atomic bonds. 5 are independently single bonds, * 4 -X 51 -C(=O)-O-,* 4 -C(=O)-NH-X 51 -or* 4 -OX 51 -.X 51 It is a hydrocarbon group having 1 to 20 carbon atoms 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 also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 2 Represents the atomic bonds to the carbon atoms of the main chain.

[0542] X 21 , X 31 and X 61 The aliphatic alkylene group represented may be any of straight chain, branched or cyclic, and specific examples thereof include alkanediyl groups such as methane-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 and hexane-1,6-diyl; cycloalkanediyl groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl and cyclohexanediyl; and groups obtained by combining these groups.

[0543] 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 those shown below, but are not limited thereto.

[0544] [Chemistry 169]

[0545]

[0546] In the formula, the dotted lines represent atomic bonds.

[0547] In formula (B6), R 21 and R 22 Each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may also contain a heteroatom. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be any of a linear, branched, or cyclic group. 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; groups obtained by combining them, etc., but preferably aryl groups. Furthermore, 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, it 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.

[0548] Again, R 21 and R 22 They may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. In this case, the ring may be exemplified as R in the description of formula (cation-1): ct1 and R ct2 The same example is true of the rings that can be formed when they are bonded to the sulfur atoms to which they are bonded.

[0549] Specific examples of the cations and anions of the repeating unit B6 include those shown below, but are not limited thereto. A Same as above.

[0550] [Chemistry 170]

[0551]

[0552] [Chemistry 171]

[0553]

[0554] [Chemistry 172]

[0555]

[0556] [Chemistry 173]

[0557]

[0558] [Chemistry 174]

[0559]

[0560] [Chemistry 175]

[0561]

[0562] [Chemistry 176]

[0563]

[0564] 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 ion, bromide ion, etc. Specific examples of the aforementioned sulfonic acid anion (sulfonate ion) include: trifluoromethanesulfonate ion, 1,1,1-trifluoroethanesulfonate ion, nonafluorobutanesulfonate ion and other fluoroalkylsulfonate ions; toluenesulfonate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, 1,2,3,4,5-pentafluorobenzenesulfonate ion and other arylsulfonate ions; methanesulfonate ion, butanesulfonate ion and other alkylsulfonate ions, etc. Specific examples of the imidic acid anion (imide ion) include bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, bis(perfluorobutylsulfonyl)imide ion, etc. Specific examples of the methide acid anion (methide ion) include tris(trifluoromethylsulfonyl)methide ion, tris(perfluoroethylsulfonyl)methide ion, etc.

[0565] Other examples of the non-nucleophilic counter ion include anions represented by any one of the following formulae (B6-1) to (B6-4).

[0566] [Chemistry 177]

[0567]

[0568] 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 straight chain, branched, or cyclic. Specific examples thereof include those exemplified below as R in formula (c1-1-1): fa1The same examples are given for the hydrocarbon groups represented.

[0569] The anion represented by the formula (B6-1) is preferably represented by the following formula (B6-1-1).

[0570] [Chemistry 178]

[0571]

[0572] In formula (B6-1-1), Q 11 and Q 12 Each of them is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 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 is particularly preferably 1. fa1 The hydrocarbon group may contain a hetero atom and has 1 to 35 carbon atoms. The hetero atom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and is more preferably an oxygen atom. The hydrocarbon group is particularly preferably a hydrocarbon group having 6 to 30 carbon atoms from the viewpoint of obtaining a high resolution when forming a fine pattern.

[0573] In formula (B6-1-1), R fa1 The hydrocarbon group having 1 to 35 carbon atoms represented by 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, heptadecyl, 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.

[0574] Furthermore, 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.

[0575] 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. From the viewpoint of synthesis, it is preferably an ether bond or an ester bond, and more preferably an ester bond.

[0576] The anions represented by formula (B6-1) include, but are not limited to, the following. 11 As mentioned above, Ac is acetyl.

[0577] [Chemistry 179]

[0578]

[0579] [Chemistry 180]

[0580]

[0581] [Chemistry 181]

[0582]

[0583] [Chemistry 182]

[0584]

[0585] [Chemistry 183]

[0586]

[0587] [Chemistry 184]

[0588]

[0589] [Chemistry 185]

[0590]

[0591] [Chemistry 186]

[0592]

[0593] [Chemistry 187]

[0594]

[0595] [Chemistry 188]

[0596]

[0597] 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 heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The same examples are given for hydrocarbon groups. fb1 and R fb2 It is preferably 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, at this time, R fb1 and R fb2 The groups obtainable by mutual bonding are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0598] 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 heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the following as examples of R in formula (B6-1-1): fa1 The same examples are given for hydrocarbon groups. fc1 , R fc2 and R fc3 It is preferably 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, at this time, R fc1 and R fc2 The groups obtainable by mutual bonding are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0599] In formula (B6-4), Rfd is a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: fa1 The same examples are given for the hydrocarbon groups represented.

[0600] Examples of the anion represented by the formula (B6-4) include the following, but are not limited thereto.

[0601] [Chemistry 189]

[0602]

[0603] [Chemistry 190]

[0604]

[0605] 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).

[0606] [Chemistry 191]

[0607]

[0608] 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.

[0609] In formula (B6-5), X BI is an iodine atom or a bromine atom, and when p and / or q is 2 or more, they may be the same as or different from each other.

[0610] 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.

[0611] 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.

[0612] In formula (B6-5), R feis 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 hydrocarbon oxy group having 1 to 20 carbon atoms, a hydrocarbon carbonyl group having 2 to 20 carbon atoms, a hydrocarbon oxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbon carbonyloxy group having 2 to 20 carbon atoms or a hydrocarbon sulfonyloxy 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 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 carbonyl oxy 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, hydrocarbon oxy 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 fe They can be the same or different.

[0613] Among them, R fe Preferably, it is 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.

[0614] In formula (B6-5), Rf 11 ~Rf 14 are independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them is a fluorine atom or a trifluoromethyl group. 11 With Rf 12 They can also be combined to form a carbonyl group. 13 and Rf 14 Preferably, they are all fluorine atoms.

[0615] The anions represented by formula (B6-5) include, but are not limited to, the following. BI Same as above.

[0616] [Chemistry 192]

[0617]

[0618] [Chemistry 193]

[0619]

[0620] [Chemistry 194]

[0621]

[0622] [Chemistry 195]

[0623]

[0624] [Chemistry 196]

[0625]

[0626] [Chemistry 197]

[0627]

[0628] [Chemistry 198]

[0629]

[0630] [Chemistry 199]

[0631]

[0632] [Chemistry 200]

[0633]

[0634] [Chemistry 201]

[0635]

[0636] [Chemistry 202]

[0637]

[0638] [Chemistry 203]

[0639]

[0640] [Chemistry 204]

[0641]

[0642] [Chemistry 205]

[0643]

[0644] [Chemistry 206]

[0645]

[0646] [Chemistry 207]

[0647]

[0648] [Chemistry 208]

[0649]

[0650] [Chemistry 209]

[0651]

[0652] [Chemistry 210]

[0653]

[0654] [Chemistry 211]

[0655]

[0656] [Chemistry 212]

[0657]

[0658] [Chemistry 213]

[0659]

[0660] [Chemistry 214]

[0661]

[0662] The aforementioned non-nucleophilic counter ions can also use fluorobenzenesulfonic acid anions bonded to an aromatic group containing an iodine atom as described in Japanese Patent No. 6648726, anions having a mechanism of decomposition by acid as described in International Publication No. 2021 / 200056 and Japanese Patent Application No. 2021-70692, anions having a cyclic ether group as described in Japanese Patent Application No. 2018-180525 and Japanese Patent Application No. 2021-35935, and anions as described in Japanese Patent Application No. 2018-92159.

[0663] The aforementioned non-nucleophilic counter ions may also use anions of bulky benzenesulfonic acid derivatives containing no fluorine atoms as described in Japanese Patent Publication Nos. 2006-276759, 2015-117200, 2016-65016, and 2019-202974, and benzenesulfonic acid anions and alkylsulfonic acid anions containing no fluorine atoms and bonded to an aromatic group containing an iodine atom as described in Japanese Patent No. 6645464.

[0664] The non-nucleophilic counter ion may also be an anion of a disulfonic acid as described in Japanese Patent Application Publication No. 2015-206932, an anion having a sulfonic acid on one side and a sulfonamide or sulfonylimide different therefrom on the other side as described in International Publication No. 2020 / 158366, or an anion having a sulfonic acid on one side and a carboxylic acid on the other side as described in Japanese Patent Application Publication No. 2015-24989.

[0665] 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 them, from the viewpoint of synthesis, an ether bond, an ester bond or a carbonyl group is preferred, and an ester bond or a carbonyl group is more preferred.

[0666] 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, it is preferred that all of them are fluorine atoms. 3 and Rf 4 Each of them is independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 3 and Rf 4 At least one of them is preferably trifluoromethyl.

[0667] In formula (B8), Rf 5 and Rf 6 are independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms. 5 and Rf 6 They cannot be hydrogen atoms at the same time. Among them, in order to improve solvent solubility, Rf 5 and Rf 6 At least one of them is preferably trifluoromethyl.

[0668] In formulae (B7) and (B8), g1 and g2 are integers of 0 to 3, preferably 1.

[0669] Specific examples of the anion of the repeating unit B7 include those shown below, but are not limited thereto. A Same as above.

[0670] [Chemistry 215]

[0671]

[0672] [Chemistry 216]

[0673]

[0674] [Chemistry 217]

[0675]

[0676] [Chemistry 218]

[0677]

[0678] [Chemistry 219]

[0679]

[0680] [Chemistry 220]

[0681]

[0682] [Chemistry 221]

[0683]

[0684] Specific examples of anions of the repeating unit B8 include those shown below, but are not limited thereto. A Same as above.

[0685] [Chemistry 222]

[0686]

[0687] [Chemistry 223]

[0688]

[0689] [Chemistry 224]

[0690]

[0691] [Chemistry 225]

[0692]

[0693] [Chemistry 226]

[0694]

[0695] [Chemistry 227]

[0696]

[0697] [Chemistry 228]

[0698]

[0699] Specific examples of anions of the repeating unit B9 include those shown below, but are not limited thereto. A Same as above.

[0700] [Chemistry 229]

[0701]

[0702] In formulas (B6) to (B9), A + is an onium cation. Examples of the onium cation include sulfonium cations, iodonium cations, ammonium cations, and the like, preferably sulfonium cations or iodonium cations. Specific examples of the sulfonium cations include the same examples as those exemplified as specific examples of the sulfonium cations represented by formula (cation-1). Specific examples of the iodonium cations include the same examples as those exemplified as specific examples of the iodonium cations represented by formula (cation-2).

[0703] Repeating units B6 to B9 are units that generate acid by irradiation with high-energy rays. It is believed that by including these units in the polymer, acid diffusion can be appropriately suppressed, and a pattern with reduced LER can be obtained. In addition, it is believed that by including these units in the polymer, the phenomenon that the acid evaporates from the exposed part and reattaches to the unexposed part during baking in a vacuum can be suppressed, and it is effective in reducing LER and reducing shape degradation caused by undesirable film loss in the unexposed part.

[0704] Among repeating units B6 to B9, the ideal units for processing blank photomasks are preferably repeating units B7 to B9, and more preferably repeating units B7 and B8, from the viewpoint of the acid strength being most suitable in suppressing acid diffusion and designing acid-labile groups of polymers.

[0705] 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 %, based on all the repeating units of the polymer. The repeating units B6 to B9 may be used alone or in combination of two or more.

[0706] Among all the repeating units of the aforementioned polymer, the content of repeating units having an aromatic ring skeleton 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.

[0707] The polymer may also contain a commonly used (meth)acrylate unit protected by an 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. These repeating units can be used to fine-tune the properties of the resist film, but these units may not be present.

[0708] Examples of the (meth)acrylate unit having an adhesion group include a repeating unit represented by the following formula (B10) (hereinafter also referred to as repeating unit B10), a repeating unit represented by the following formula (B11) (hereinafter also referred to as repeating unit B11), and a repeating unit represented by the following formula (B12) (hereinafter also referred to as repeating unit B12). These units do not exhibit acidity and can be used auxiliaryly as units for providing adhesion to a substrate or units for adjusting solubility.

[0709] [Chemistry 230]

[0710]

[0711] 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.

[0712] When repeating units B10 to B12 are contained, their content is preferably 0 to 20 mol%, more preferably 0 to 10 mol%, based on all repeating units of the polymer. Repeating units B10 to B12 may be used alone or in combination of two or more.

[0713] The above polymer can be synthesized by copolymerizing monomers protected by protecting 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. These methods can be referred to Japanese Patent Publication No. 2004-115630.

[0714] The weight average molecular weight (Mw) of the above-mentioned polymer is preferably 1000 to 50000, and more preferably 2000 to 20000. If Mw is above 1000, there is no concern that the head of the pattern becomes rounded and the resolution is reduced, and the LER deteriorates as known. On the other hand, if Mw is below 50000, there is no concern that the LER deteriorates, especially when forming a pattern with a line width of 100nm or less. In addition, Mw in the present invention is a polystyrene-converted measurement value obtained by gel permeation chromatography (GPC) using THF or DMF as a solvent.

[0715] The molecular weight distribution (Mw / Mn) of the polymer is 1.0 to 2.0, preferably 1.0 to 1.9, and more preferably 1.0 to 1.8. When the molecular weight distribution is narrow, foreign matter will not be generated on the pattern after development, and the pattern shape will not be deteriorated.

[0716] In addition, with respect to the above-mentioned base polymer design, the dissolution rate of the base polymer in the alkaline developer is preferably less than 10 nm / min, more preferably less than 7 nm / min, and even more preferably less than 5 nm / min. In the advanced generation, when the coating film applied to the substrate is in the thin film area (less than 100 nm), the influence on the pattern film loss of the alkaline development will become greater. When the alkaline dissolution rate of the polymer is greater than 10 nm / min, the pattern will collapse and a fine pattern cannot be formed. Especially in the production of photomasks that require no defects, there is a tendency for the development process to be stronger, so it is more significant. In addition, in the present invention, the dissolution rate of the base polymer in the alkaline developer is a value calculated from the film loss amount when the polymer solution (polymer concentration: 16.7% by mass, solvent: propylene glycol monomethyl ether acetate (PGMEA)) is spin-coated on an 8-inch silicon wafer and baked at 100°C for 90 seconds to form a film with a thickness of 1000 nm, and then developed at 23°C for 100 seconds using a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution.

[0717] The base polymer of the component (B) may contain other polymers other than the aforementioned polymers. Other polymers known as base polymers for resist compositions may be used. The content of other polymers is not particularly limited as long as the effects of the present invention are not impaired.

[0718] [(C) Organic solvent]

[0719] 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 each component. 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 Application 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) , ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether and other ethers; 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, propylene glycol monotert-butyl ether acetate and other esters; lactones such as γ-butyrolactone; mixed solvents thereof, etc. When an acid-labile group of an acetal system is used, in order to accelerate the deprotection reaction of the acetal, a high-boiling alcohol solvent may be added, specifically, diethylene glycol, propylene glycol, glycerol, 1,4-butanediol, 1,3-butanediol and the like may be added.

[0720] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, and a mixed solvent thereof are preferred.

[0721] 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.

[0722] [(D) Fluorine-containing polymer]

[0723] The chemically amplified positive resist composition of the present invention may contain a fluorine atom-containing polymer as component (D) in order to achieve high contrast, suppress the chemical flare phenomenon of acid during high-energy ray irradiation, shield the acid from the antistatic film when the antistatic film material is applied to the resist film, and suppress unexpected and unwanted pattern degradation. The fluorine atom-containing polymer contains at least one selected from the repeating unit represented by the following formula (D1) (hereinafter also referred to as repeating unit D1), the repeating unit represented by the following formula (D2) (hereinafter also referred to as repeating unit D2), the repeating unit represented by the following formula (D3) (hereinafter also referred to as repeating unit D3) and the repeating unit represented by the following formula (D4) (hereinafter also referred to as repeating unit D4), and may further contain at least one selected from the repeating unit represented by the following formula (D5) (hereinafter also referred to as repeating unit D5) and the repeating unit represented by the following formula (D6) (hereinafter also referred to as repeating unit D6). The aforementioned fluorine-atom-containing polymer also has a surfactant function, so it can prevent insoluble matter that may be generated during the development process from re-attaching to the substrate, and thus also has an effect on preventing development defects.

[0724] [Chemistry 231]

[0725]

[0726] 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 are each independently a hydrogen atom or a methyl group. 101 , R 102 , R 104 and R 105 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 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 R 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. 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. 111Z 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 portion of the -CH2- in 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 to 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 to a carbon atom of the main chain.

[0727] 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 any of 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 them, saturated hydrocarbon groups having 1 to 6 carbon atoms are preferred.

[0728] In formulas (D1) to (D4), R 103 , R 106 , R 107 and R 108 The hydrocarbon group having 1 to 15 carbon atoms represented by the term "alkyl" may be any of straight chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 15 carbon atoms, alkenyl groups having 2 to 15 carbon atoms, and alkynyl groups having 2 to 15 carbon atoms. Preferably, the alkyl group has 1 to 15 carbon atoms. The aforementioned alkyl group may include, in addition to the aforementioned groups, 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, and n-pentadecyl. Further, the fluorinated hydrocarbon group may include groups in which a part or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon group are substituted with fluorine atoms.

[0729] In formula (D4), Z 1The (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms represented by may be 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 Examples of the (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by include groups in which at least one hydrogen atom in the aforementioned (k+1)-valent hydrocarbon group is substituted with a fluorine atom.

[0730] Specific examples of repeating units D1 to D4 include the following, but are not limited thereto. B Same as above.

[0731] [Chemistry 232]

[0732]

[0733] [Chemistry 233]

[0734]

[0735] [Chemistry 234]

[0736]

[0737] In formula (D5), R 109 and R 110 The hydrocarbon group having 1 to 5 carbon atoms represented by alkyl, alkenyl, alkynyl, etc., preferably alkyl. The aforementioned alkyl group includes methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, etc. In addition, a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms may be inserted between the carbon-carbon bonds of the aforementioned hydrocarbon groups.

[0738] In formula (D5), -OR 109 Preferably, it is a hydrophilic group. 109 Preferred are hydrogen atoms, alkyl groups having 1 to 5 carbon atoms in which an oxygen atom is inserted between carbon-carbon bonds, and the like.

[0739] In formula (D5), Z 2 It is preferably *-C(=O)-O- or *-C(=O)-NH-. C Preferably, Z is methyl. 2 The presence of a carbonyl group in the antistatic film improves the capture ability of the acid from the antistatic film. C If it is a methyl group, it will become a hard polymer with a higher glass transition temperature (Tg), so the diffusion of acid will be suppressed. As a result, the stability of the resist film over time will be good, and the resolution and pattern shape will not deteriorate.

[0740] The repeating unit D5 may be exemplified by the following, but is not limited thereto. C Same as above.

[0741] [Chemistry 235]

[0742]

[0743] [Chemistry 236]

[0744]

[0745] In formula (D6), Z 3 The saturated alkylene group having 1 to 10 carbon atoms represented by the alkylene group 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.

[0746] In formula (D6), R 111 The saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted by a fluorine atom may be straight-chain, branched or cyclic. 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 substituted by a fluorine atom.

[0747] The repeating unit D6 may be exemplified by the following, but is not limited thereto. C Same as above.

[0748] [Chemistry 237]

[0749]

[0750] [Chemistry 238]

[0751]

[0752] [Chemistry 239]

[0753]

[0754] [Chemistry 240]

[0755]

[0756] 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.

[0757] (D) The fluorine-containing polymer may contain other repeating units other than the aforementioned repeating units. Such repeating units include those described in paragraphs

[0046] to

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

[0758] (D) The fluorine-containing polymer can be synthesized by copolymerizing monomers protected by protective groups as required by known methods, followed by deprotection reactions as required. The copolymerization reaction is not particularly limited, and is preferably free radical polymerization or anionic polymerization. These methods can be found in Japanese Patent Publication No. 2004-115630.

[0759] The Mw of the fluorine-containing polymer (D) is preferably 2,000 to 50,000, more preferably 3,000 to 20,000. If the Mw is less than 2,000, the diffusion of the acid may be promoted, resulting in degradation of the resolution and loss of stability over time. If the Mw is too large, the solubility in the solvent may decrease and coating defects may occur. In addition, the Mw / Mn of the fluorine-containing polymer (D) is preferably 1.0 to 2.2, more preferably 1.0 to 1.7.

[0760] 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.

[0761] [(E) Quencher]

[0762] The chemically amplified positive resist composition of the present invention may contain a quencher as component (E) as needed. In addition, the quencher in the present invention refers to a compound that captures the acid generated from the acid generator. This can suppress the diffusion rate of the acid generated from the acid generator when it diffuses in the resist film, and even when a substrate whose outermost surface is composed of a chromium-containing material is used, the influence of the acid generated in the resist film on the chromium-containing material can be suppressed.

[0763] The quencher may be a known basic compound. Examples of the known basic compound include 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 are preferred, and 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 particularly preferred. Preferred 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.

[0764] In addition, the quencher may be an onium salt such as a sulfonium salt, an iodonium salt, or an ammonium salt of a carboxylic acid at the α-position that is not fluorinated as described in Japanese Patent Application Laid-Open No. 2008-158339. A sulfonic acid, an imidic acid, or a methylated acid at the α-position that is fluorinated is necessary for deprotecting an acid-labile group, and the carboxylic acid at the α-position that is not fluorinated is released by salt exchange with an onium salt at the α-position that is not fluorinated. The carboxylic acid at the α-position that is not fluorinated hardly causes a deprotection reaction, and thus functions as a quencher.

[0765] Examples of the onium salt of carboxylic acid in which the α-position is not fluorinated include those represented by the following formula (E1).

[0766] [Chemistry 241]

[0767] R 201 -CO2 - Mq A + (E1)

[0768] In formula (E1), R 201 It is a hydrocarbon group having 1 to 40 carbon atoms which may contain a hydrogen atom or a hetero atom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the carboxyl group is substituted by a fluorine atom or a fluoroalkyl group.

[0769] 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.

[0770] Furthermore, 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, and halogen atoms, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain hydroxyl groups, cyano groups, carbonyl groups, ether bonds, thioether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, and the like. Examples of the heteroatom-containing hydrocarbon group include heteroaryl groups such as thienyl; alkoxyphenyl groups such as 4-hydroxyphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 4-tert-butoxyphenyl, and 3-tert-butoxyphenyl; alkoxynaphthyl groups such as methoxynaphthyl, ethoxynaphthyl, n-propoxynaphthyl, and n-butoxynaphthyl; dialkoxynaphthyl groups such as dimethoxynaphthyl and diethoxynaphthyl; aryloxyalkyl groups such as 2-aryl-2-oxoethyl groups such as 2-phenyl-2-oxoethyl, 2-(1-naphthyl)-2-oxoethyl, and 2-(2-naphthyl)-2-oxoethyl; and the like.

[0771] 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 is more preferably a sulfonium cation or an iodonium cation. Specific examples of the sulfonium cation include the same examples as those exemplified as the specific examples of the sulfonium cation represented by formula (cation-1). Specific examples of the iodonium cation include the same examples as those exemplified as the specific examples of the iodonium cation represented by formula (cation-2).

[0772] Examples of the anion of the onium salt represented by the formula (E1) include the following, but are not limited thereto.

[0773] [Chemistry 242]

[0774]

[0775] [Chemistry 243]

[0776]

[0777] [Chemistry 244]

[0778]

[0779] As the quencher, a sulfonium salt of a carboxylic acid containing an iodinated benzene ring represented by the following formula (E2) can also be preferably used.

[0780] [Chemistry 245]

[0781]

[0782] In formula (E2), s is an integer of 1 to 5. t is an integer of 0 to 3. However, 1≤s+t≤5. u is an integer of 1 to 3.

[0783] 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, wherein a part or all of the hydrogen atoms may be 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 can be the same or different.

[0784] 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 carbonyl oxy group, and saturated hydrocarbon sulfonyl oxy group may be straight-chain, branched, or cyclic.

[0785] In formula (E2), R 212 , R 213 and R 214 Each independently represents 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 any of linear, branched, and 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, aralkyl groups having 7 to 20 carbon atoms, and the like. 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.

[0786] Specific examples of the compound represented by formula (E2) include those described in Japanese Patent Application Laid-Open No. 2017-219836. The compound represented by formula (E2) has a high sensitization effect due to high absorption and also has a high acid diffusion control effect.

[0787] The quencher may be a nitrogen atom-containing carboxylate type compound represented by the following formula (E3).

[0788] [Chemistry 246]

[0789]

[0790] In formula (E3), R 221 ~R 224 are 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 R is a single bond or a alkylene group having 1 to 20 carbon atoms which may contain a hetero atom. 225It is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hydrogen atom or a hetero atom.

[0791] In formula (E3), ring R r is a ring having 2 to 6 carbon atoms including the carbon atoms and nitrogen atoms in the formula, and part or all of the hydrogen atoms bonded to the carbon atoms in the ring may be replaced by a hydrocarbon group having 1 to 20 carbon atoms, or -L 12 -CO2 - The ring may be an alicyclic ring or an aromatic ring, and preferably a 5-membered ring or a 6-membered ring. Specific examples thereof include: pyridine ring, pyrrole ring, pyrrolidine ring, piperidine ring, pyrazole ring, imidazoline ring, pyridazine ring, pyrimidine ring, pyrazine ring, imidazoline ring, oxazole ring, thiazole ring, morpholine ring, thiazine ring, triazole ring, etc.

[0792] 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.

[0793] In formula (E3), Mq B + It is a sulfonium cation, an iodonium cation or an ammonium cation, preferably a sulfonium cation. Specific examples of the sulfonium cation include the same examples as those exemplified as the specific examples of the sulfonium cation represented by the formula (cation-1).

[0794] Examples of the anion of the compound represented by formula (E3) include the following, but are not limited thereto.

[0795] [Chemistry 247]

[0796]

[0797] [Chemistry 248]

[0798]

[0799] [Chemistry 249]

[0800]

[0801] [Chemistry 250]

[0802]

[0803] [Chemistry 251]

[0804]

[0805] [Chemistry 252]

[0806]

[0807] Furthermore, the quencher may be a weakly acidic betaine-type compound. Specific examples thereof include those shown below, but are not limited thereto.

[0808] [Chemistry 253]

[0809]

[0810] The aforementioned quencher may further include a polymer quencher described in Japanese Patent Application Publication No. 2008-239918. The 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 doming of the pattern when using a protective film for immersion exposure.

[0811] When the chemically amplified positive resist composition of the present invention contains a quencher, its content is preferably 0 to 50 parts by mass, more preferably 0.1 to 40 parts by mass, relative to 80 parts by mass of the base polymer. The quencher may be used alone or in combination of two or more.

[0812] 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 even more preferably less than 2 in terms of mass ratio. When the content ratio of the photoacid generator to the quencher contained 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.

[0813] [(F) Other photoacid generators]

[0814] 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.

[0815] Specific examples of the above-mentioned other photoacid generators include: nonafluorobutane sulfonates, partially fluorinated sulfonates described in paragraphs

[0247] to

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

[0261] to

[0265] of Japanese Patent Application Laid-Open No. 2013-101271, paragraphs

[0122] to

[0142] of Japanese Patent Application Laid-Open No. 2008-111103, and paragraphs

[0080] to

[0081] of Japanese Patent Application Laid-Open No. 2010-215608. Among the above-mentioned specific examples, the photoacid generator of the arene sulfonate type or the alkane sulfonate type is more preferable because it generates an acid of appropriate strength when the acid-labile group of the repeating unit B2 is deprotected.

[0816] Such a photoacid generator is preferably a salt compound containing an anion shown below.

[0817] [Chemistry 254]

[0818]

[0819] [Chemistry 255]

[0820]

[0821] [Chemistry 256]

[0822]

[0823] [Chemistry 257]

[0824]

[0825] [Chemistry 258]

[0826]

[0827] [Chemistry 259]

[0828]

[0829] [Chemistry 260]

[0830]

[0831] [Chemistry 261]

[0832]

[0833] [Chemistry 262]

[0834]

[0835] [Chemistry 263]

[0836]

[0837] [Chemistry 264]

[0838]

[0839] [Chemistry 265]

[0840]

[0841] [Chemistry 266]

[0842]

[0843] [Chemistry 267]

[0844]

[0845] [Chemistry 268]

[0846]

[0847] [Chemistry 269]

[0848]

[0849] [Chemistry 270]

[0850]

[0851] [Chemistry 271]

[0852]

[0853] [Chemistry 272]

[0854]

[0855] [Chemistry 273]

[0856]

[0857] [Chemistry 274]

[0858]

[0859] [Chemistry 275]

[0860]

[0861] [Chemistry 276]

[0862]

[0863] [Chemistry 277]

[0864]

[0865] [Chemistry 278]

[0866]

[0867] [Chemistry 279]

[0868]

[0869] [Chemistry 280]

[0870]

[0871] [Chemistry 281]

[0872]

[0873] [Chemistry 282]

[0874]

[0875] [Chemistry 283]

[0876]

[0877] [Chemistry 284]

[0878]

[0879] [Chemistry 285]

[0880]

[0881] [Chemistry 286]

[0882]

[0883] [Chemistry 287]

[0884]

[0885] [Chemistry 288]

[0886]

[0887] [Chemistry 289]

[0888]

[0889] [Chemistry 290]

[0890]

[0891] [Chemistry 291]

[0892]

[0893] [Chemistry 292]

[0894]

[0895] [Chemistry 293]

[0896]

[0897] [Chemistry 294]

[0898]

[0899] [Chemistry 295]

[0900]

[0901] [Chemistry 296]

[0902]

[0903] [Chemistry 297]

[0904]

[0905] [Chemistry 298]

[0906]

[0907] [Chemistry 299]

[0908]

[0909] [Chemistry 300]

[0910]

[0911] [Chemistry 301]

[0912]

[0913] [Chemistry 302]

[0914]

[0915] [Chemistry 303]

[0916]

[0917] [Chemistry 304]

[0918]

[0919] [Chemistry 305]

[0920]

[0921] [Chemistry 306]

[0922]

[0923] [Chemistry 307]

[0924]

[0925] [Chemistry 308]

[0926]

[0927] [Chemistry 309]

[0928]

[0929] [Chemistry 310]

[0930]

[0931] [Chemistry 311]

[0932]

[0933] [Chemistry 312]

[0934]

[0935] [Chemistry 313]

[0936]

[0937] [Chemistry 314]

[0938]

[0939] Furthermore, the photoacid generator is preferably a salt compound containing an anion represented by the following formula (F1).

[0940] [Chemistry 315]

[0941]

[0942] 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.

[0943] 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.

[0944] In formula (F1), L 22It is an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond.

[0945] 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, and 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.

[0946] L D The alkylene 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: 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 specific examples of the aforementioned hydrocarbon groups having 1 to 20 carbon atoms.

[0947] In formula (F1), Rf 21 and Rf 22 Each of them is independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, and at least one of them is a fluorine atom or a trifluoromethyl group.

[0948] 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 R is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms.301C is 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.

[0949] 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 hydrocarbon groupoxyl group having 1 to 6 carbon atoms represented by R is exemplified by the same specific examples as those of the saturated hydrocarbon group described above. 301 The saturated hydrocarbon group portion of the saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms represented by the carbonyl group may include those having 1 to 5 carbon atoms among the specific examples of the saturated hydrocarbon group having 1 to 6 carbon atoms described above.

[0950] R 301D The unsaturated aliphatic hydrocarbon group having 2 to 8 carbon atoms represented may be any of 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; cyclic unsaturated aliphatic hydrocarbon groups having 3 to 8 carbon atoms such as cyclohexenyl and norbornenyl, etc.

[0951] 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 hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbon oxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogen atom and a hydroxyl group.

[0952] 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. Specific examples thereof include and are exemplified as L D The same examples apply to the alkylene group having 1 to 20 carbon atoms.

[0953] R 302Specific examples of the arylene group having 6 to 20 carbon atoms represented by phenylene, naphthylene, phenanthrenediyl, anthracenediyl, etc. The saturated hydrocarbon group having 1 to 20 carbon atoms and the hydrocarbon group part of the hydrocarbonoxy group having 1 to 20 carbon atoms, which are substituents of the arylene group, may be any of linear, branched, and 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, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, 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 which is a substituent of the arylene group include a phenylene group, a naphthylene group, a phenanthrenediyl group, an anthracenediyl group, and the like.

[0954] The anion represented by the formula (F1) is preferably an anion represented by the following formula (F2).

[0955] [Chemistry 316]

[0956]

[0957] 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 hydrocarbon oxy group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, a halogen atom or a hydroxyl group. 302A They can be the same or different.

[0958] Specific examples of the anion represented by formula (F1) include the following, but are not limited thereto.

[0959] [Chemistry 317]

[0960]

[0961] [Chemistry 318]

[0962]

[0963] [Chemistry 319]

[0964]

[0965] [Chemistry 320]

[0966]

[0967] [Chemistry 321]

[0968]

[0969] [Chemical formula 322]

[0970]

[0971] [Chemical formula 323]

[0972]

[0973] [Chemical formula 324]

[0974]

[0975] [Chemical formula 325]

[0976]

[0977] [Chemical formula 326]

[0978]

[0979] [Chemical formula 327]

[0980]

[0981] [Chemical formula 328]

[0982]

[0983] [Chemical formula 329]

[0984]

[0985] [Chemical formula 330]

[0986]

[0987] [Chemical formula 331]

[0988]

[0989] [Chemical formula 332]

[0990]

[0991] [Chemical formula 333]

[0992]

[0993] [Chemical formula 334]

[0994]

[0995] [Chemical formula 335]

[0996]

[0997] [Chemical Formula 336]

[0998]

[0999] [Chemical Formula 337]

[1000]

[1001] [Chemical Formula 338]

[1002]

[1003] [Chemical Formula 339]

[1004]

[1005] [Chemical Formula 340]

[1006]

[1007] [Chemical Formula 341]

[1008]

[1009] [Chemical Formula 342]

[1010]

[1011] [Chemical Formula 343]

[1012]

[1013] [Chemical Formula 344]

[1014]

[1015] [Chemical Formula 345]

[1016]

[1017] [Chemical Formula 346]

[1018]

[1019] [Chemical Formula 347]

[1020]

[1021] [Chemical Formula 348]

[1022]

[1023] [Chemical Formula 349]

[1024]

[1025] [Chemistry 350]

[1026]

[1027] [Chemistry 351]

[1028]

[1029] [Chemistry 352]

[1030]

[1031] [Chemistry 353]

[1032]

[1033] (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 include the same examples as those exemplified as the sulfonium cation represented by formula (cation-1), but are not limited thereto. Specific examples of the iodonium cation include the same examples as those exemplified as the iodonium cation represented by formula (cation-2), but are not limited thereto.

[1034] The pKa of the acid generated by the aforementioned other photoacid generator is preferably -2.0 or higher, more preferably -1.0 or higher. The upper limit of the pKa is preferably 2.0. The pKa value is obtained using pKa DB in the software ACD / Chemsketch ver: 9.04 manufactured by Advanced Chemistry Development, Inc.

[1035] When the chemically amplified positive resist composition of the present invention contains (F) another photoacid generator, 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 another photoacid generator, the amount of acid generated in the exposed portion and the dissolution barrier of the unexposed portion can be appropriately adjusted. (F) Another photoacid generator may be used alone or in combination of two or more.

[1036] The chemically amplified positive resist composition of the present invention preferably contains, in addition to the photoacid generator (A), a polymer-bonded photoacid generator containing repeating units represented by formulas (B6) to (B9) or (F) other photoacid generators. 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.

[1037] [(G) Surfactant]

[1038] The chemically amplified positive resist composition of the present invention may contain a conventional surfactant as component (G) in order to improve the coating property on the substrate. The aforementioned surfactant is well known in many cases, such as those described in International Publication No. 2006 / 121096, Japanese Patent Application Publication No. 2008-102383, Japanese Patent Application Publication No. 2008-304590, Japanese Patent Application Publication No. 2004-115630, and Japanese Patent Application Publication No. 2005-8766, and may be selected with reference to these.

[1039] 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, relative to 80 parts by mass of the (B) base polymer, and its lower limit is preferably 0.01 parts by mass or more. The (G) surfactant may be used alone or in combination of two or more.

[1040] [Resist pattern forming method]

[1041] The resist pattern forming method of the present invention comprises the following steps:

[1042] Using the chemically amplified positive resist composition to form a resist film on a substrate,

[1043] The resist film is exposed to high energy radiation, and

[1044] The resist film irradiated with the above pattern is developed using an alkaline developer to obtain a resist pattern.

[1045] 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 a film thickness of 0.03 to 2 μm, and is pre-baked on a hot plate at preferably 60 to 150° C. for 1 to 20 minutes, and more preferably 80 to 140° C. for 1 to 10 minutes, to form a resist film.

[1046] Then, the resist film is exposed to a pattern using high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, extreme ultraviolet radiation, excimer laser (KrF, ArF, etc.), EB, EUV, X-rays, gamma rays, and synchrotron radiation.

[1047] When ultraviolet rays, extreme ultraviolet rays, excimer lasers, EUV, X-rays, gamma rays, or synchrotron radiation are used as the high-energy radiation, a mask for forming a target pattern is used, and the exposure dose is preferably 1 to 300 mJ / cm 2 More preferably, it is 10 to 200 mJ / cm 2 When using EB, the exposure dose should be 1 to 300 μC / cm 2 More preferably, it is 10 to 200 μC / cm 2 In addition, the chemically amplified positive resist composition of the present invention is particularly useful in EUV or EB lithography.

[1048] Exposure may 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 may be used.

[1049] Then, a post-exposure bake (PEB) is performed on a hot plate at preferably 60-150° C. for 1-20 minutes, and more preferably 80-140° C. for 1-10 minutes.

[1050] Thereafter, a developer containing an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) preferably at a concentration of 0.1 to 5% by mass and more preferably at a concentration of 2 to 3% by mass is used, and development is performed for 0.1 to 3 minutes and preferably at a concentration of 0.5 to 2 minutes using a common method such as a dip method, a puddle method, or a spray method, thereby forming a desired pattern on the substrate.

[1051] The chemically amplified positive resist composition of the present invention is useful when it is required to have particularly high etching resistance and when it is used under the conditions that even when the time from exposure to PEB is extended, the change in pattern line width is small and the LER is still small. In addition, the resist composition of the present invention is particularly useful when it is applied to a substrate whose surface has a material that is easy to cause pattern peeling and pattern collapse due to the difficulty in obtaining the adhesion of the resist pattern. Such substrates include substrates formed by sputtering metal chromium, 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 in pattern formation using a blank photomask as a substrate.

[1052] Example

[1053] Hereinafter, the present invention will be specifically described with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples.

[1054] IR: NICOLET 6700 manufactured by Thermo Fisher Scientific

[1055] · 1 H-NMR: ECA-500 manufactured by JEOL Ltd.

[1056] ·MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[1057] [1] Synthesis of onium salts

[1058] [Example 1-1] Synthesis of PAG-1

[1059] [Chemistry 354]

[1060]

[1061] (1) Synthesis of intermediate In-1

[1062] Under nitrogen environment, in a reaction container, 3,5-diiodosalicylic acid (195.0 g), potassium carbonate (105.9 g) and sodium iodide (7.5 g) are suspended in DMF (1000 g). The temperature in the reaction container is raised to 50°C, and 1-bromooctane (212.4 g) 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 (1000 g) is added to stop the reaction. The target substance is extracted with a solution composed of hexane (1000 g) and toluene (250 g), and the usual aqueous work-up is performed. The solvent is distilled off to obtain 306.3 g of intermediate In-1 (yield 100%) in the form of an oil. The intermediate In-1 is used in subsequent steps without further purification.

[1063] (2) Synthesis of intermediate In-2

[1064] Under nitrogen environment, in a reaction vessel, the intermediate In-1 (306.3 g) was dissolved in THF (700 g). 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 reaction was heated to reflux at a temperature of 70°C in the reaction vessel and matured 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 adjusted to 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 the intermediate In-2 (yield 65%) in the form of white crystals.

[1065] (3) Synthesis of onium salt PAG-1

[1066] Under nitrogen atmosphere, in a reaction vessel, the intermediate In-2 (10.1 g) and DMF (0.02 g) were dissolved in dichloromethane (40 g). Thereafter, oxalyl chloride (3.1 g) was added dropwise at room temperature. After addition, the temperature in the reaction vessel was raised to 40°C and ripened for 4 hours to obtain an acyl chloride. After ripening, the reaction solution was distilled off and 12.6 g of acyl chloride was obtained. Thereafter, the acyl chloride (12.6 g), SM-2 (10.6 g), and 4-dimethylaminopyridine (0.3 g) were suspended in acetonitrile (60 g). The temperature in the reaction vessel was raised to 50°C, and a solution consisting of triethylamine (2.6 g) and acetonitrile (10 g) was added dropwise. After addition, the temperature in the reaction vessel was raised to 70°C and ripened for 12 hours. After ripening, the reaction solution was cooled and water (50 g) was added to stop the reaction. Thereafter, the target product was extracted with dichloromethane, subjected to a conventional aqueous work-up, and the solvent was distilled off to obtain 17.0 g of onium salt PAG-1 as an oily substance (yield 86%).

[1067] 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.

[1068] IR(D-ATR): ν=3058,3021,2926,2855,1749,1593,1583,1565,1537,1465,1440,1383,1322,1271,1253,12 30,1185,1145,1085,1061,1040,997,912,885,815,765,733,714,664,639,622,593,562,526,487,439cm -1 .

[1069] MALDI TOF-MS: POSITIVE M + 277 (equivalent to C 18 H 13 OS + )

[1070] NEGATIVE M - 713 (equivalent to C 25 H 31 I2O6S - )

[1071] [Examples 1-2 to 1-10] Synthesis of PAG-2 to PAG-10

[1072] Onium salts PAG-2 to PAG-10 represented by the following formulae were synthesized using corresponding raw materials and known organic synthesis reactions.

[1073] [Chemistry 355]

[1074]

[1075] [Chemistry 356]

[1076]

[1077] 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.

[1078] IR(D-ATR): ν=3063,2927,2856,1737,1593,1574,1534,1466,1440,1371,1322,126 9,1251,1148,1100,1041,968,911,886,761,706,682,658,636,617,562,526,488cm -1 .

[1079] MALDI TOF-MS: POSITIVE M + 277 (equivalent to C 18 H 13 OS + )

[1080] NEGATIVE M - 713 (equivalent to C 25 H 31 I2O6S - )

[1081] 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.

[1082] IR(D-ATR): ν=3059,3020,2927,2857,1729,1605,1581,1510,1465,1441,1392,1318,1271,1250,1216 ,1168,1150,1088,1066,1040,966,910,886,846,816,765,733,716,682,655,632,587,561,524,487cm-1 .

[1083] MALDI TOF-MS: POSITIVE M + 277 (equivalent to C 18 H 13 OS + )

[1084] NEGATIVE M - 461 (equivalent to C 25 H 33 O6S - )

[1085] [2] Synthesis of base polymer

[1086] [Synthesis Example] Synthesis of base polymers (P-1 to P-6)

[1087] The monomers were combined using a known formula and copolymerized in a solvent. The reaction solution was added to hexane, and the precipitated solid was washed with hexane, separated, and dried to obtain base polymers (P-1 to P-6) with the following compositions. 1 H-NMR, 13 The molecular weight was confirmed by C-NMR, and the Mw and Mw / Mn were confirmed by GPC (solvent: THF, standard: polystyrene).

[1088] [Chemistry 357]

[1089]

[1090] [Chemistry 358]

[1091]

[1092] [3] Preparation of chemically amplified positive resist composition

[1093] [Examples 2-1 to 2-50, Comparative Examples 1-1 to 1-31]

[1094] The components were dissolved in an organic solvent according to the compositions shown in Tables 1 to 3 below, and the obtained solution was filtered through a nylon filter of 5 nm size and a UPE filter of 1 nm size, thereby preparing a chemically amplified positive resist composition. In addition, the aforementioned organic solvent is a mixed solvent of 940 parts by mass of PGMEA, 1870 parts by mass of EL, and 1870 parts by mass of PGME.

[1095] [Table 1]

[1096]

[1097]

[1098] [Table 2]

[1099]

[1100]

[1101] [Table 3]

[1102]

[1103]

[1104] In addition, in Tables 1 to 3, comparative photoacid generators cPAG-1 to cPAG-6, quenchers Q-1 to Q-4, and fluorine-containing polymers FP-1 to FP-5 are as follows.

[1105] [Chemistry 359]

[1106]

[1107] [Chemistry 360]

[1108]

[1109] [Chemistry 361]

[1110]

[1111] [4]EB Lithography Evaluation

[1112] [Examples 3-1 to 3-50, Comparative Examples 2-1 to 2-31]

[1113] 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 blank mask as a reflective blank for EUV exposure mask, which was formed with a 284nm thick Mo / Si40-layer multilayer reflective film on a 6-inch low thermal expansion glass substrate, 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, and pre-baked on a hot plate at 110°C for 600 seconds to obtain a resist film with a 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 10 mm inward from the outer periphery, and the average film thickness and film thickness range were obtained.

[1114] The resist film was exposed using an electron beam exposure apparatus (EBM-5000plus manufactured by NuFlare Technology Co., Ltd., accelerating voltage 50 kV), PEB was applied at 110° C. for 600 seconds, and development was performed with a 2.38 mass % TMAH aqueous solution to obtain a positive pattern.

[1115] The obtained resist pattern was evaluated as follows. The obtained blank mask with pattern was observed using an overhead SEM (scanning electron microscope), and the exposure amount at which a 1:1 line and space (LS) of 200 nm was resolved at 1:1 was defined as the optimum exposure amount (μC / cm 2 ), and defined the minimum size when the exposure dose of 200nm isolated spacing was resolved at 9:1 as the resolution (limit IS resolution), and the LER of 200nmLS was measured using SEM. The pattern shape was visually determined to be rectangular. The results are shown in Tables 4 to 6.

[1116] [Table 4]

[1117]

[1118] [Table 5]

[1119]

[1120] [Table 6]

[1121]

[1122]

[1123] The results shown in Tables 4 to 6 indicate 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 during the processing of transmissive and reflective blank photomasks.

Claims

1. An onium salt represented by the following formula (A); Wherein, n1 is 0 or 1; n2 is 1, 2 or 3; n3 is an integer from 0 to 4; n4 is an integer from 0 to 4; however, when n1 is 0, 1≤n2+n3+n4≤5, and when n1 is 1, 1≤n2+n3+n4≤7; n5 is 0, 1 or 2; n6 is an integer of 0 to 4 when n5 is 0, an integer of 0 to 6 when n5 is 1, and an integer of 0 to 8 when n5 is 2; n7 is an integer of 0 to 4 when n5 is 0, an integer of 0 to 6 when n5 is 1, and an integer of 0 to 8 when n5 is 2; however, n6+n7 is 0 to 4 when n5 is 0, 0 to 6 when n5 is 1, and 0 to 8 when n5 is 2; 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; R 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; further, 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; R 2 is a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when n7 is 2 or more, a plurality of R 2 They can also bond to each other and to the carbon atoms to which they are bonded to form rings; R F1 is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated thioalkoxy group having 1 to 6 carbon atoms; when n6 is 2 or more, each R F1 They can be the same or different from each other; L A , L B and L C are 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 heteroatoms; Z + It is an onium cation.

2. The onium salt according to claim 1, which is represented by the following formula (A1); In the formula, n1~n4, n6, n7, R alk , R 1 , R 2 , R F1 , L A , L B , L C , X L and Z + Same as above.

3. The onium salt according to claim 2, which is represented by the following formula (A2); In the formula, n1~n4, n6, n7, R alk , R 1 , R 2 , R F1 , L A , L C , X L and Z + Same as above.

4. The onium salt according to claim 1, wherein Z + It 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 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, which is composed of 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 comprising a polymer that is decomposed by an acid and increases its 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; 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 hydrocarbon oxy 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, and a part of the -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 hydrocarbon oxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom; A 2 It is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a portion of -CH2- in 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, 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 from 0 to 2; c2 is an integer from 0 to 2; c3 is an integer from 0 to 5; c4 is an integer from 0 to 2; R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; R 13 and R 14 are each independently a hydrocarbon group having 1 to 10 carbon atoms which may contain a hetero atom, and 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 Each independently represents a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom; 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; * is an atomic bond to 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; 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 of them 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 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; 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 carbonyl oxy group having 2 to 20 carbon atoms, a saturated hydrocarbon oxy hydrocarbon group having 2 to 20 carbon atoms, a saturated hydrocarbon thio hydrocarbon group having 2 to 20 carbon atoms, a halogen atom, a nitro group, or a cyano group, and may also be a hydroxyl group when f2 is 1 or 2; A 4 It is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of the -CH2- of 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 An aliphatic alkylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining them, and may also contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group;* 1 Indicates and X 1 Atomic bonds; X 3 are independently a single bond, phenylene, naphthylene or * 2 -C(=O)-OX 31 -;X 31 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 with the carbon atoms of the main chain; X 4 are independently single bonds, * 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 heteroatoms; 3 Indicates and X 3 Atomic bonds; X 5 are independently single bonds, * 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 heteroatoms; 4 Indicates and X 4 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 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 also contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group;* 2 Represents the atomic bonds with 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 independently a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; R 3 and Rf 4 are independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; R 5 and Rf 6 are independently a hydrogen atom, a fluorine atom or a fluorinated saturated hydrocarbon group having 1 to 6 carbon atoms; however, all Rf 5 and Rf 6 It will not be a hydrogen atom at the same time; M - It 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 6, further comprising an organic solvent.

14. The chemically amplified positive resist composition according to claim 6, 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 further 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; 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 Each is 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 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 A hydrogen atom or a straight-chain 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 A saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is replaced by a fluorine atom, and a portion of -CH2- in the saturated hydrocarbon group may be replaced by an ester bond or an ether bond; Z 1 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 to 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 is a single bond, an ester bond, an ether bond or a sulfonamide bond; * is an atomic bond to a carbon atom of the main chain.

15. The chemically amplified positive resist composition according to claim 6, further comprising a quencher. 16 . The chemically amplified positive resist composition according to claim 6 , 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: forming a resist film on a substrate using the chemically amplified positive resist composition according to any one of claims 6 to 16, The resist film is exposed to high energy radiation, 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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