Chemically amplified positive resist composition and resist pattern forming method

Abstract

The invention relates to a chemically amplified positive resist composition and a resist pattern forming method. The present invention addresses the problem of providing: a chemically amplified positive resist composition which is capable of forming a resist film that can form a pattern having extremely high resolution, low LER, excellent rectangularity, and suppressed influence on residue defects of a developer; and a resist pattern forming method using the composition. The solution of the present invention is a chemically amplified positive resist composition comprising (A) a base polymer, (B) a photoacid generator, and (C) a quencher, (A) the base polymer comprising a polymer containing a specific phenolic hydroxyl group-containing unit, a specific aromatic ring-containing unit, and a specific phenolic hydroxyl group-containing unit protected by an acid-labile group, the repeating units contained in the (A) base polymer are all repeating units having aromatic rings, and the number of halogen atoms contained in the repeating units constituting the (A) base polymer is 3 or less.

Description

Technical Field

[0001] The present invention relates to 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. In the processing of patterns below 0.2μm, chemically amplified resist compositions using acids as catalysts are mainly used. In addition, the exposure source at this time uses high-energy rays such as ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), and electron beams (EB). In particular, EB lithography, which is used as an ultra-fine processing technology, is also indispensable for the processing method of blank photomasks when making photomasks for semiconductor manufacturing.

[0003] In EB lithography, the depiction by EB is generally performed without using a mask. In the case of positive type, the EB of a fine area is sequentially irradiated to the parts other than the area where the resist film is to remain, and in the case of negative type, the EB of a fine area is sequentially irradiated to the area where the resist film is to remain. That is, in order to scan the entire area of ​​the fine subdivision of the processing surface, it takes more time than a one-time exposure using a photomask, and a highly sensitive resist film is required in order not to reduce the yield. In particular, in the processing of blank photomasks for important purposes, surface materials such as chromium compound films such as chromium oxide formed on the photomask substrate that are easy to affect the pattern shape of the chemically amplified resist film, in order to maintain high resolution and the shape after etching, regardless of the type of substrate, it is one of the important properties to keep the pattern outline of the resist film as a rectangle. In addition, a small line edge roughness (LER) is also considered to be one of the important properties. In recent years, in order to achieve miniaturization, multi-beam mask writing (MBMW) drawing processing is sometimes used in the processing of blank masks. In this case, the resist composition uses a low-sensitivity resist composition (high-dose area) that is beneficial to roughness, and the optimization of the resist composition in the high-dose area has attracted attention.

[0004] Regarding the control of sensitivity and pattern profile, various improvements are made according to the selection, combination, processing conditions, etc. of the materials used in the resist composition. One of the improvements is to suppress the diffusion of acid, which has a significant impact on the resolution of the resist film. For the processing of photomasks, it is required that the shape of the resist pattern obtained does not change depending on the time from exposure to heating. The reason why the time-dependent change of the resist pattern shape is large is the diffusion of the acid generated by exposure. The problem of the diffusion of the acid is not limited to photomask processing, and even in general resist compositions, it will have a significant impact on the sensitivity and resolution, so a lot of research has been conducted.

[0005] Patent Documents 1 and 2 describe examples of reducing LER by increasing the volume of acid generated by an acid generator to suppress acid diffusion. However, such suppression of acid diffusion by an acid generator is not sufficient, and development of an acid generator with a smaller acid diffusion is required.

[0006] In addition, Patent Document 3 describes an example of controlling acid diffusion by introducing a repeating unit having a sulfonium structure that generates sulfonic acid upon exposure into a polymer used in a resist composition. Such a method of introducing a repeating unit that generates acid upon exposure into a base polymer to suppress acid diffusion is effective as a method for obtaining a pattern with a small LER. However, a base polymer containing such a repeating unit that generates acid upon exposure may have problems with solubility in organic solvents depending on the structure and introduction rate of the unit.

[0007] Polymers having a large number of aromatic skeletons with acidic side chains, such as polyhydroxystyrene, are useful as base polymers for KrF lithography resist compositions, but they exhibit significant absorption of light with a wavelength of around 200 nm and cannot be used as base polymers for ArF lithography resist compositions. However, for EB lithography resist compositions and EUV lithography resist compositions, which are powerful technologies for forming patterns smaller than the processing limit of ArF excimer lasers, they are important materials from the perspective of obtaining high etching resistance.

[0008] For the base polymer of the positive EB lithography resist composition and the EUV lithography resist composition, a material that is soluble in an alkaline developer by deprotecting the acid-labile group that masks the acidic functional group of the phenol side chain of the base polymer is mainly used, using the acid generated by irradiating a photoacid generator with high-energy rays as a catalyst. As for the acid-labile group, in addition to a tertiary alkyl group and a tert-butoxycarbonyl group, an acetal group is used as an acid-labile group with a small activation energy (Patent Documents 4 to 8).

[0009] However, although the acetal group has the advantage of obtaining a highly sensitive resist film, since the MBMW drawing process in EB lithography used to produce advanced photomasks, especially below the 10nm node, is performed in a thin film region of the resist film with a thickness of less than 100nm and in a high-dose region with a large irradiation energy, the acetal group has high reactivity and deprotection reaction will occur even in the unexposed portion of the resist film, resulting in a problem of degradation of resolution and roughness, which are considered important, especially in positive resist compositions.

[0010] In addition, in the development step of photomask manufacturing, in order to minimize mask defects, there is a tendency to use a larger amount of developer and the development conditions are stronger than the so-called KrF, ArF or EUV lithography using wafers. It is important to design a resist suitable for such a strong development process, and it is hoped to develop a resist composition that can achieve high resolution, reduce roughness and reduce development residual defects even in the advanced generation.

[0011] Prior art literature

[0012] Patent Literature

[0013] [Patent Document 1] Japanese Patent Application Publication No. 2009-53518

[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. 3981830

[0017] [Patent Document 5] Japanese Patent No. 5385017

[0018] [Patent Document 6] International Publication No. 2019-167419

[0019] [Patent Document 7] Japanese Patent No. 6987873

[0020] [Patent Document 8] International Publication No. 2019-044259 Summary of the invention

[0021] [Problems to be solved by the invention]

[0022] In order to solve the above-mentioned problems, the present invention aims to provide a chemically amplified positive resist composition that can form a resist film with a pattern having extremely high isolated pitch resolution, small LER, excellent rectangularity, and suppressed influence of residue defects caused by a developer, and a resist pattern forming method using the chemically amplified positive resist composition.

[0023] [Methods to solve the problem]

[0024] The inventors of the present application have conducted repeated and diligent studies to achieve the above-mentioned purpose, and have found that by using a base polymer having an acetal-type acid-labile group having a structure in which a carbon atom bonded to two oxygen atoms is bonded to an aromatic ring, a photoacid generator and a quencher, and a resist composition in which the content ratio of the photoacid generator to the quencher is controlled, a pattern that exhibits good resolution, pattern shape and roughness even in a high-dose area and in which the influence of residue defects is suppressed can be obtained, thereby completing the present invention.

[0025] That is, the present invention provides the following chemically amplified positive resist composition and resist pattern forming method.

[0026] 1. A chemically amplified positive resist composition comprising (A) a base polymer, (B) a photoacid generator and (C) a quencher,

[0027] (A) a base polymer comprising a polymer containing a phenolic hydroxyl group-containing unit represented by the following formula (A1), an aromatic ring-containing unit represented by any of the following formulas (A2) to (A4), and a phenolic hydroxyl group-containing unit protected by an acid-labile group represented by the following formula (A5),

[0028] (A) All repeating units contained in the base polymer are repeating units having an aromatic ring,

[0029] The number of halogen atoms contained in the repeating unit constituting the base polymer (A) is 3 or less,

[0030] [Chemistry 1]

[0031]

[0032] In the formula, a1 is an integer satisfying 0≤a1≤5+2(a3)-a2, a2 ​​is an integer from 1 to 3, and a3 is an integer from 0 to 2.

[0033] R A , is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0034] X 1 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond to a carbon atom of the main chain,

[0035] A 1 , is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, a part of -CH2- of the saturated alkylene group may be substituted by -O-,

[0036] R 1, is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom,

[0037] [Chemistry 2]

[0038]

[0039] In the formula, b and c are each independently an integer of 0 to 4, d1 is an integer of 0 to 5, d2 is an integer of 0 to 2,

[0040] R A , is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0041] X 2 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond to a carbon atom of the main chain,

[0042] A 2 , is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, a part of -CH2- of the saturated alkylene group may be substituted by -O-,

[0043] R 2 and R 3 , each independently represents a hydroxyl group, 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 8 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 8 carbon atoms which may be substituted by a halogen atom,

[0044] R 4 , is an acetyl group, 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 thiol group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group, and when d2 is 1 or 2, it may also be a hydroxyl group,

[0045] [Chemistry 3]

[0046]

[0047] In the formula, e1 is an integer satisfying 0≤e1≤5+2(e3)-e2, e2 is an integer from 1 to 3, and e3 is an integer from 0 to 2.

[0048] R A , is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0049] X 3 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond to a carbon atom of the main chain,

[0050] A 3 , is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, a part of -CH2- of the saturated alkylene group may be substituted by -O-,

[0051] R 5 , is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom,

[0052] R AL When e2 is 1, it is an acetal-type acid-labile group represented by the following formula (AL-1); when e2 is 2 or more, it is a hydrogen atom or an acetal-type acid-labile group represented by the following formula (AL-1), but at least one of them is an acetal-type acid-labile group represented by the following formula (AL-1),

[0053] [Chemistry 4]

[0054]

[0055] Wherein, f1 is an integer from 0 to 2, f2 is an integer satisfying 0≤f2≤5+2(f1),

[0056] R 6 , is an acetyl group, a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbon oxy group having 1 to 20 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbon oxyalkyl group having 2 to 20 carbon atoms, a saturated hydrocarbon thialkyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group,

[0057] R L1 , is a hydrocarbon group having 1 to 30 carbon atoms,

[0058] Dashed lines are atomic bonds.

[0059] 2. The chemically amplified positive resist composition of 1, wherein the unit containing a phenolic hydroxyl group is a repeating unit represented by the following formula (A1-1):

[0060] [Chemistry 5]

[0061]

[0062] In the formula, R A and a2, the same as above.

[0063] 3. The chemically amplified positive resist composition of 1 or 2, wherein the unit containing a phenolic hydroxyl group protected by an acid-labile group is a repeating unit represented by the following formula (A5-1):

[0064] [Chemistry 6]

[0065]

[0066] In the formula, R A , R 6 , f1, f2 and R L1 , the same as above.

[0067] 4. The chemically amplified positive resist composition according to any one of 1 to 3, wherein the acid strength (pKa) of the acid generated by the (B) photoacid generator is greater than or equal to -3.0.

[0068] 5. The chemically amplified positive resist composition according to any one of 1 to 4, wherein the content ratio of the (B) photoacid generator to the (C) quencher ((B) / (C)) is less than 3 in terms of mass ratio.

[0069] 6. The chemically amplified positive resist composition according to any one of 1 to 5, wherein the photoacid generator (B) is an onium salt compound containing an anion represented by the following formula (B-1) or (B-2),

[0070] [Chemistry 7]

[0071]

[0072] In the formula, m1 and m2 are each independently an integer of 0 to 2, when m1=0, m3 is an integer of 1 to 5, when m1=1, m3 is an integer of 1 to 7, when m1=2, m3 is an integer of 1 to 9, when m2=0, m4 is an integer of 0 to 5, when m2=1, m4 is an integer of 0 to 7, when m2=2, m4 is an integer of 0 to 9,

[0073] L 1 , is a single bond, an ether bond, an ester bond, a sulfonate bond, an amide bond, a carbonate bond or a carbamate bond,

[0074] R 11 , each independently an iodine atom, or a branched or cyclic hydrocarbon group having 3 to 20 carbon atoms which may contain a hetero atom, at least one R 11 Yes and L 1 The carbon atom to which the bond is bonded is bonded to the adjacent carbon atom. When m3 is 2 or more, multiple R 11 They may also be bonded to each other and form a ring together with these bonded carbon atoms.

[0075] R 12 , each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when m4 is 2 or more, a plurality of R 12 They may also be bonded to each other and form a ring together with these bonded carbon atoms.

[0076] W 1 , is the carbon atom C of the adjacent aromatic ring1 and C 2 The carbon atoms forming the ring may be substituted with a heteroatom-containing group.

[0077] W 2 , is the carbon atom C of the adjacent aromatic ring 3 and C 4 The carbon atoms forming the ring may be substituted with a heteroatom-containing group.

[0078] [Chemistry 8]

[0079]

[0080] wherein n1 and n2 are each independently an integer of 0 to 2, when n2=0, n3 is an integer of 1 to 4, when n2=1, n3 is an integer of 1 to 6, when n2=2, n3 is an integer of 1 to 8, when n2=0, n4 is an integer of 0 to 3, when n2=1, n4 is an integer of 0 to 5, when n2=2, n4 is an integer of 0 to 7, but when n2=0, n3+n4 is 1 to 4, when n2=1, n3+n4 is 1 to 6, when n2=2, n3+n4 is 1 to 8, when n1=0, n5 is an integer of 1 to 5, when n1=1, n5 is an integer of 1 to 7, when n1=2, n5 is an integer of 1 to 9,

[0081] R 21 , each independently an iodine atom, or a branched or cyclic hydrocarbon group having 3 to 20 carbon atoms which may contain a hetero atom, at least one R 21 , is and L 11 The carbon atom to which the carbon atom is bonded is bonded to the adjacent carbon atom, and when n5 is 2 or more, multiple R 21 They may also be bonded to each other and form a ring together with these bonded carbon atoms.

[0082] R 22 , each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when n4 is 2 or more, a plurality of R 22 They may also be bonded to each other and form a ring together with these bonded carbon atoms.

[0083] R F1 , each independently represents 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,

[0084] L 11 and L 12 , is a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond or a carbamate bond,

[0085] X L, is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom.

[0086] 7. The chemically amplified positive resist composition of 6, wherein (B) the photoacid generator is an onium salt compound having no fluorine atom in the anion.

[0087] 8. The chemically amplified positive resist composition according to any one of 1 to 7, further comprising (D) a fluorine-containing polymer, which contains 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 contain 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),

[0088] [Chemistry 9]

[0089]

[0090] Wherein, x is 1, 2 or 3, y is an integer satisfying 0≤y≤5+2z-x, z is 0 or 1, k is 1, 2 or 3,

[0091] R B , are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0092] R C , are each independently a hydrogen atom or a methyl group,

[0093] R 101 , R 102 , R 104 and R 105 , each independently a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms,

[0094] R 103 , R 106 , R 107 and R 108 , each independently a hydrogen atom, a hydrocarbon group having 1 to 15 carbon atoms, a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group, R 103 , R 106 , R 107 and R 108 When it is a hydrocarbon group or a fluorinated hydrocarbon group, the carbon-carbon bond may be separated by an ether bond or a carbonyl group.

[0095] R 109 , is a straight-chain or branched hydrocarbon group having 1 to 5 carbon atoms, which may be separated by a hydrogen atom or a heteroatom-containing group between carbon-carbon bonds,

[0096] R 110, is a linear or branched hydrocarbon group having 1 to 5 carbon atoms, wherein a heteroatom-containing group may be present between carbon-carbon bonds,

[0097] R 111 , is a saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted by a fluorine atom, and a portion of -CH2- in the saturated hydrocarbon group may be substituted by an ester bond or an ether bond,

[0098] Z 1 , is a (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms,

[0099] Z 2 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-,

[0100] 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,

[0101] * are atomic bonds to carbon atoms of the backbone chain.

[0102] 9. The chemically amplified positive resist composition according to any one of 1 to 8, further comprising (E) an organic solvent.

[0103] 10. The chemically amplified positive resist composition according to any one of 1 to 9, wherein the dissolution rate of the base polymer in an alkaline developer is 5 nm / min or less.

[0104] 11. The chemically amplified positive resist composition according to any one of 1 to 10, wherein the dissolution rate of the unexposed portion of the resist film obtained from the chemically amplified positive resist composition in an alkaline developer is 10 nm / min or less.

[0105] 12. The chemically amplified positive resist composition according to any one of 1 to 11, which is used for electron beam lithography.

[0106] 13. A method for forming a resist pattern, comprising the following steps: forming a resist film on a substrate using a chemically amplified positive resist composition as described in any one of 1 to 12, irradiating a pattern on the resist film using extreme ultraviolet rays or electron beams, and developing the resist film irradiated with the pattern using an alkaline developer.

[0107] 14. The resist pattern forming method according to 13, wherein the outermost surface of the substrate is composed of a material containing at least one selected from the group consisting of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten and tin.

[0108] 15. The resist pattern forming method according to 13 or 14, wherein the substrate is a transmission type or reflection type blank mask.

[0109] 16. A transmission or reflection type blank mask coated with the chemically amplified positive resist composition according to any one of 1 to 12.

[0110] [Effects of the Invention]

[0111] The chemically amplified positive resist composition of the present invention is capable of forming a pattern having high resolution, low LER, good rectangularity after exposure, and a pattern in which the influence of residual defects caused by a developer is suppressed, and is suitable as a resist composition for forming a resist film that is sensitive to EB used in the processing of semiconductors, blank photomasks, etc. In addition, the pattern forming method using the chemically amplified positive resist composition of the present invention can form a pattern having high resolution, etching resistance, reduced LER, and a pattern in which the influence of residual defects caused by a developer is suppressed, so it can be suitable for use in micro-processing technology, especially EUV lithography and EB lithography. DETAILED DESCRIPTION

[0112] The present invention is described in detail below. In the following description, if there is an asymmetric carbon and there may be mirror image isomers and non-mirror image isomers according to the structure represented by the chemical formula, in this case, one chemical formula is used to represent these isomers. The isomers may be used alone or as a mixture.

[0113] [Chemically amplified positive resist composition]

[0114] The chemically amplified positive resist composition of the present invention comprises (A) a base polymer, (B) a photoacid generator and (C) a quencher.

[0115] [(A) Base polymer]

[0116] The base polymer of the component (A) includes a polymer containing a phenolic hydroxyl group-containing unit represented by the following formula (A1) (hereinafter, also referred to as repeating unit A1).

[0117] [Chemistry 10]

[0118]

[0119] In formula (A1), a1 is an integer satisfying 0≤a1≤5+2(a3)-a2. a2 is an integer of 1 to 3. a3 is an integer of 0 to 2.

[0120] In formula (A1), R A , is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0121] In formula (A1), X 1 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is an atomic bond to a carbon atom of the main chain.

[0122] In formula (A1), A 1 , is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, and a part of -CH2- of the saturated alkylene group may be substituted by -O-. The saturated alkylene group may be straight chain, branched chain or cyclic. Specific examples thereof include alkane diyl 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 cyclopropane diyl, cyclobutane diyl, cyclopentane diyl, and cyclohexane diyl; and groups obtained by combining these groups.

[0123] In formula (A1), R 1 , is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom. The saturated hydrocarbon group, the saturated hydrocarbon carbonyloxy group, and the saturated hydrocarbon part of the saturated hydrocarbonoxy group may be straight chain, branched chain, or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, and hexyl; 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 alkaline developer is good. When a1 is 2 or more, each R 1 , may be the same as or different from each other.

[0124] X 1 and A 1 When all of them are single bonds, preferred examples of repeating unit A1 include units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, etc. Among these, more preferred are repeating units represented by the following formula (A1-1).

[0125] [Chemistry 11]

[0126]

[0127] In the formula, RA and a2, the same as above.

[0128] X 1 When it is other than a single bond, the following are preferred examples of the repeating unit A1, but the present invention is not limited thereto. A , the same as above.

[0129] [Chemistry 12]

[0130]

[0131] [Chemistry 13]

[0132]

[0133] The repeating unit A1 is preferably introduced in the range of 30 to 90 mol % of all the repeating units of the polymer contained in the base polymer, and is more preferably introduced in the range of 60 to 85 mol %. However, in the case where the polymer described later contains at least one of the repeating units represented by formula (A2) and the repeating units represented by formula (A3) that provide higher etching resistance, and this unit has a phenolic hydroxyl group as a substituent, it is also preferred that the ratio of addition falls within the aforementioned range. Repeating unit A1 can be used alone or in combination of two or more.

[0134] The aforementioned polymer further comprises at least one selected from an aromatic ring-containing unit represented by the following formula (A2) (hereinafter, also referred to as repeating unit A2), an aromatic ring-containing unit represented by the following formula (A3) (hereinafter, also referred to as repeating unit A3) and an aromatic ring-containing unit represented by the following formula (A4) (hereinafter, also referred to as repeating unit A4).

[0135] [Chemistry 14]

[0136]

[0137] In formulae (A2) and (A3), b and c are each independently an integer of 0-4.

[0138] In formula (A2) and (A3), R 2 and R 3 , each independently represents a hydroxyl group, 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 8 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 8 carbon atoms which may be substituted by a halogen atom. The aforementioned saturated hydrocarbon group, saturated hydrocarbonoxy group, and saturated hydrocarbon carbonyloxy group may be straight-chain, branched, or cyclic. When b is 2 or more, each R 2 , may be the same as or different from each other. When c is 2 or more, each R 3 , may be the same as or different from each other.

[0139] In formula (A4), R A , is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. d1, is an integer of 0 to 5. d2, is an integer of 0 to 2.

[0140] In formula (A4), R 4 , is an acetyl group, 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 d2 is 1 or 2, R 4 The aforementioned saturated hydrocarbon group, saturated hydrocarbon oxy group, saturated hydrocarbon carbonyloxy group, saturated hydrocarbon oxyalkyl group and saturated hydrocarbon thioalkyl group may be straight chain, branched chain or cyclic. 4 , may be the same as or different from each other.

[0141] In formula (A4), X 2 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is an atomic bond to a carbon atom of the main chain.

[0142] In formula (A4), A 2 , 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. Specific examples thereof include the following: 1 The same as those exemplified in the description of .

[0143] When repeating units A2 to A4 are used, in addition to the etching resistance of the aromatic ring, the addition of a ring structure to the main chain can also improve the EB irradiation resistance during etching and pattern inspection.

[0144] In order to obtain the effect of improving etching resistance, it is preferred that repeating units A2 to A4 are introduced in an amount of 5 mol% or more in all repeating units of the polymer contained in the base polymer. In addition, it is preferred that repeating units A2 to A4 are introduced in an amount of 25 mol% or less in all repeating units of the polymer contained in the base polymer, and it is more preferred that they are introduced in an amount of 20 mol% or less. In the case of having no functional group or the case where the functional group is other than hydroxyl group, if the introduction amount is 25 mol% or less, there is no concern about the generation of development defects, so it is ideal. Repeating units A2 to A4 can be used alone or in combination of two or more.

[0145] The content of at least one selected from the repeating unit A1 and the repeating units A2 to A4 in all the repeating units of the base polymer is preferably 60 mol % or more, more preferably 70 mol % or more.

[0146] The aforementioned polymer further includes a phenolic hydroxyl group-containing unit protected by an acid-labile group represented by the following formula (A5) (hereinafter, also referred to as repeating unit A5).

[0147] [Chemistry 15]

[0148]

[0149] In formula (A5), R A , is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. e1, is an integer satisfying 0≤e1≤5+2(e3)-e2. e2, is an integer from 1 to 3. e3, is an integer from 0 to 2.

[0150] In formula (A5), X 3 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is an atomic bond to a carbon atom of the main chain.

[0151] In formula (A5), A 3 , 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. Specific examples thereof include the following: 1 The same as those exemplified in the description of .

[0152] In formula (A5), R 5 , is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom. The saturated hydrocarbon group, the saturated hydrocarbon carbonyloxy group, and the saturated hydrocarbon part of the saturated hydrocarbonoxy group may be straight chain, branched chain, or cyclic. Specific examples thereof include the following: 1 The same as those exemplified in the description of . If the carbon number is below the upper limit, the solubility in the alkaline developer is good. When e1 is 2 or more, each R 5 , may be the same as or different from each other.

[0153] In formula (A5), R AL When e2 is 1, it is an acetal-type acid-unstable group represented by the following formula (AL-1); when e2 is 2 or more, it is a hydrogen atom or an acetal-type acid-unstable group represented by the following formula (AL-1), but at least one of them is an acetal-type acid-unstable group represented by the following formula (AL-1).

[0154] [Chemistry 16]

[0155]

[0156] Dashed lines are atomic bonds.

[0157] In the formula (AL-1), f1 is an integer of 0 to 2. f2 is an integer satisfying 0≤f2≤5+2(f1).

[0158] In formula (AL-1), R 6 , is an acetyl group, a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbon oxy group having 1 to 20 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbon oxyalkyl group having 2 to 20 carbon atoms, a saturated hydrocarbon thialkyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group.

[0159] R 6 , can be appropriately selected according to the design of the sensitivity of the acid-decomposable group. In order to further optimize the acetal separation reaction, various substituents such as hydrogen atoms, electron-donating groups, and electron-attracting groups can be selected, but it is better to select electron-attracting groups in terms of the ease of controlling the separation reactivity. In addition, when halogen atoms are selected, considering the reactivity control and compatibility with alkaline developer, and the viewpoint of suppressing development defects, the halogen atoms are preferably 3 or less, and regarding iodine atoms, considering the viewpoint of solubility in resist solvents, it is better to be 2 or less.

[0160] Just R AL The structural characteristics of the acetal-type acid-labile group shown in FIG. 1 include an aromatic ring bonded to a carbon atom bonded to two oxygen atoms. Compared with an alkyl group or a cycloalkyl group, it is easier to optimize the acid-leaving reaction and the etching resistance is also improved.

[0161] In formula (AL-1), R L1 , is a hydrocarbon group with 1 to 30 carbon atoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. The carbon atoms forming the hydrocarbon group may be substituted by heteroatoms such as oxygen atoms and sulfur atoms to form ether bonds or sulfur bonds. Specific examples thereof 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 L1 , preferably a hydrocarbon group having 1 to 6 carbon atoms. L1 In the case of a hydrocarbon group having 1 to 6 carbon atoms, the alcohol generated after the deprotection reaction with an acid is water-soluble and dissolves in an alkaline developer when a positive pattern is formed. This can suppress residue defects in the exposed portion.

[0162] Just R L1 Specific examples of the group represented by include those shown below, but are not limited to these. In the following formula, * represents an atomic bond with an adjacent -O-.

[0163] [Chemistry 17]

[0164]

[0165] [Chemistry 18]

[0166]

[0167] Specific examples of the acetal-type acid-labile group represented by formula (AL-1) include those shown below, but are not limited to these. L1 As before, dashed lines are atomic bonds.

[0168] [Chemistry 19]

[0169]

[0170] [Chemistry 20]

[0171]

[0172] [Chemistry 21]

[0173]

[0174] [Chemistry 22]

[0175]

[0176] [Chemistry 23]

[0177]

[0178] The phenolic hydroxyl group-containing unit protected by the acid-labile group is preferably represented by the following formula (A5-1).

[0179] [Chemistry 24]

[0180]

[0181] In the formula, R A , R 6 , f1, f2 and R L1 , the same as above.

[0182] As a method for protecting a polymer with an acetal-type acid-labile group after polymerization, a method using vinyl ether and an acid catalyst, a method using an acetalizing agent having a haloalkoxy group together with a base, etc. are known. Here, a method using an acetalizing agent having a haloalkoxy group together with a base is preferred.

[0183] The method of using the acetalizing agent having a haloalkoxy group together with a base is a method of dropping the acetalizing agent having a haloalkoxy group in the presence of a basic compound such as triethylamine. The reaction temperature is -20 to 50°C and the reaction time is 0.2 to 10 hours, preferably 0.5 to 6 hours.

[0184] The repeating units protected by the acetal acid-labile group are preferably introduced in an amount of 10 to 40 mol %, more preferably 10 to 30 mol %, and even more preferably 20 to 30 mol % based on all repeating units of the polymer contained in the base polymer.

[0185] The aforementioned base polymer, in addition to the polymer having the aforementioned acetal-type acid-labile group, may also contain a polymer having a known acid-labile group other than the acetal-type acid-labile group represented by formula (AL-1) such as a tertiary alkyl group and a tert-butyloxycarbonyl group. In this case, the polymer having an acid-labile group other than the acetal-type acid-labile group represented by formula (AL-1) preferably includes a repeating unit having an acid-labile group other than the acetal-type acid-labile group represented by formula (AL-1) and a repeating unit A1, and may include repeating units A2 to A4 as needed. In order to exert the effect of the present invention, the proportion of the base polymer having the aforementioned acetal-type acid-labile group in all the base polymers contained in the chemically amplified positive resist composition of the present invention is preferably 50% or more.

[0186] The number of halogen atoms contained in the repeating unit constituting the base polymer is preferably 3 or less. If the number of halogen atoms is 4 or more, the solubility in an alkaline developer decreases, and thus development residues may be generated.

[0187] The aforementioned acetal acid-labile group also has the effect of suppressing the influence of backscattering during EB drawing, so at 50μC / cm 2 Above, preferably 80μC / cm 2 Above, better than 100μC / cm 2 In the above sensitivity range, the pattern shape will not become an inverse cone but will exhibit rectangular performance.

[0188] For the aforementioned base polymer, the weight average molecular weight (Mw) is preferably 1000 to 20000, and more preferably 4000 to 7000. If Mw is above 1000, there will be no concerns about the phenomenon such as pattern doming and reduced resolution, and LER degradation as known in the past. On the other hand, if Mw is below 20000, there will be no concerns about LER degradation when forming a pattern, especially when the pattern line width is below 100nm. In addition, Mw in the present invention is a polystyrene-converted measurement value obtained by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or dimethylformamide (DMF) as a solvent.

[0189] The molecular weight distribution (Mw / Mn) of the base polymer is narrowly dispersed in the range of 1.0 to 2.0, preferably 1.0 to 1.8, and more preferably 1.0 to 1.6. With such a narrow dispersion, after development, foreign matter will not be generated on the pattern or the shape of the pattern will not be deteriorated.

[0190] In addition, with respect to the above-mentioned base polymer design, the dissolution rate of the base polymer in the alkaline developer is preferably 10 nm / min or less, more preferably 7 nm / min or less, and even more preferably 5 nm / min or less. In the advanced generation, when the coating film on the substrate is a thin film region (less than 100 nm), the influence of the pattern film loss on the alkaline development becomes greater. When the alkaline dissolution rate of the polymer is greater than 10 nm / min, the pattern will collapse, and it becomes impossible to form a fine pattern. In particular, when a defect-free photomask is required to be produced, it tends to be more pronounced due to the tendency to undergo a strong development process. In addition, the dissolution rate of the base polymer in the alkaline developer in the present invention is a value calculated from the film loss amount when a 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 with a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution.

[0191] [(B) Photoacid generator]

[0192] The chemically amplified positive resist composition of the present invention may also contain a photoacid generator. The photoacid generator is not particularly limited as long as it is a compound that generates acid by irradiation with high-energy rays. Preferred photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate acid generators, and the like.

[0193] Specific examples of the photoacid generator include nonafluorobutanesulfonate, partially fluorinated sulfonates described in paragraphs

[0247] to

[0251] of JP-A-2012-189977, partially fluorinated sulfonates described in paragraphs

[0261] to

[0265] of JP-A-2013-101271, paragraphs

[0122] to

[0142] of JP-A-2008-111103, paragraphs

[0080] to

[0081] of JP-A-2010-215608, fluorobenzenesulfonic acid type, etc. Among the above specific examples, arylsulfonate type or alkanesulfonate type photoacid generators are preferred because they generate an acid of appropriate strength when the acid-labile group of the repeating unit represented by formula (A5) is deprotected.

[0194] Such a photoacid generator is preferably an onium salt compound having an anion having the structure shown below.

[0195] [Chemistry 25]

[0196]

[0197] [Chemistry 26]

[0198]

[0199] [Chemistry 27]

[0200]

[0201] [Chemistry 28]

[0202]

[0203] [Chemistry 29]

[0204]

[0205] [Chemistry 30]

[0206]

[0207] [Chemistry 31]

[0208]

[0209] [Chemistry 32]

[0210]

[0211] [Chemistry 33]

[0212]

[0213] The photoacid generator as the component (B) is preferably an onium salt compound containing an anion represented by the following formula (B-1).

[0214] [Chemistry 34]

[0215]

[0216] In formula (B-1), m1 and m2 are each independently an integer of 0 to 2. When m1=0, it represents a benzene ring, when m1=1, it represents a naphthalene ring, and when m1=2, it represents an anthracene ring. From the viewpoint of solvent solubility, it is preferably a benzene ring with m1=0. Moreover, from the viewpoint of solvent solubility, m2 is preferably 0.

[0217] In formula (B-1), when m1=0, m3 is an integer of 1 to 5, when m1=1, m3 is an integer of 1 to 7, and when m1=2, m3 is an integer of 1 to 9. When m2=0, m4 is an integer of 0 to 5, when m2=1, m4 is an integer of 0 to 7, and when m2=2, m4 is an integer of 0 to 9.

[0218] In formula (B-1), L 1 , is a single bond, an ether bond, an ester bond, a sulfonate bond, an amide bond, a carbonate bond or a carbamate bond. Among these, an ether bond, an ester bond, a sulfonate bond is preferred, and a sulfonate bond is more preferred.

[0219] In formula (B-1), R 11 , is an iodine atom, or a branched or cyclic hydrocarbon group having 3 to 20 carbon atoms which may contain a hetero atom, at least one R 11 Yes and L 1 Specific examples of the hydrocarbon group include isopropyl, sec-butyl, tert-butyl, tert-pentyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo[5.2.1.0 2,6 ] aliphatic cyclic hydrocarbon groups having 3 to 20 carbon atoms, such as decyl and adamantyl; aryl groups, such as phenyl, naphthyl, anthracenyl; groups obtained by combining them, etc., but are not limited to these. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., as a result, hydroxyl groups, cyano groups, halogen atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may also be included. As for the aforementioned halogen atoms, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc. may be listed, preferably fluorine atoms or iodine atoms. When m3 is 2 or more, each R 11 , may be the same as or different from each other.

[0220] When m3 is 2 or more, multiple R 11 , and may also be bonded to each other and form a ring together with these bonded carbon atoms. As for the aforementioned ring, it is preferably a 5- to 8-membered ring.

[0221] In formula (B-1), R 12 , each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may also contain heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 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 20 carbon atoms, such as decyl, adamantyl, and adamantylmethyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and anthracenyl. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by groups 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 groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in hydroxyl groups, cyano groups, halogen 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. As for the aforementioned halogen atoms, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, and the like are listed, preferably fluorine atoms or iodine atoms. When m4 is 2 or more, each R 12 , may be the same as or different from each other.

[0222] When m4 is 2 or more, multiple R 12 , and may also be bonded to each other and form a ring together with these bonded carbon atoms. As for the aforementioned ring, it is preferably a 5- to 8-membered ring.

[0223] In formula (B-1), W 1 , is the carbon atom C of the adjacent aromatic ring 1 and C 2 The ring having 3 to 15 carbon atoms formed together may be partially substituted with a heteroatom-containing group. The aforementioned ring may be monocyclic or polycyclic. 2 , is the carbon atom C of the adjacent aromatic ring 3 and C 4 In the ring having 3 to 15 carbon atoms formed together, part of the carbon atoms forming the ring may be substituted with a heteroatom-containing group. The above-mentioned ring may be a monocyclic ring or a polycyclic ring.

[0224] In formula (B-1), W 1 and W 2 The structures formed by condensing the adjacent aromatic rings include the following, but are not limited to these. 1 of atomic bonds.

[0225] [Chemistry 35]

[0226]

[0227] In formula (B-1), R 11 The following structures can be cited as examples of structures formed by bonding of L and aromatic rings, but are not limited to these. 1 of atomic bonds.

[0228] [Chemistry 36]

[0229]

[0230] [Chemistry 37]

[0231]

[0232] [Chemistry 38]

[0233]

[0234] [Chemistry 39]

[0235]

[0236] [Chemistry 40]

[0237]

[0238] [Chemistry 41]

[0239]

[0240] The anion represented by the formula (B-1) is preferably one represented by the following formula (B-1-1).

[0241] [Chemistry 42]

[0242]

[0243] In the formula, m2, m3, m4, L 1 , R 11 , R 12 , W 1 and W 2 , the same as above.

[0244] The anion represented by the formula (B-1-1) is preferably represented by the following formula (B-1-2).

[0245] [Chemistry 43]

[0246]

[0247] In the formula, m3, m4, R 11 , R 12 and W 1 , the same as above.

[0248] Particularly preferred examples of the anion represented by formula (B-1) include those shown below, but are not limited to these.

[0249] [Chemistry 44]

[0250]

[0251] [Chemistry 45]

[0252]

[0253] [Chemistry 46]

[0254]

[0255] [Chemistry 47]

[0256]

[0257] [Chemistry 48]

[0258]

[0259] [Chemistry 49]

[0260]

[0261] [Chemistry 50]

[0262]

[0263] [Chemistry 51]

[0264]

[0265] [Chemistry 52]

[0266]

[0267] [Chemistry 53]

[0268]

[0269] [Chemistry 54]

[0270]

[0271] [Chemistry 55]

[0272]

[0273] [Chemistry 56]

[0274]

[0275] [Chemistry 57]

[0276]

[0277] [Chemistry 58]

[0278]

[0279] [Chemistry 59]

[0280]

[0281] [Chemistry 60]

[0282]

[0283] [Chemistry 61]

[0284]

[0285] [Chemistry 62]

[0286]

[0287] [Chemistry 63]

[0288]

[0289] [Chemistry 64]

[0290]

[0291] [Chemistry 65]

[0292]

[0293] [Chemistry 66]

[0294]

[0295] [Chemistry 67]

[0296]

[0297] The onium salt containing the anion represented by formula (B-1) is an onium salt of a sulfonic acid that is not substituted by a fluorine atom, so it can generate an acid of appropriate strength by irradiation with high-energy rays. In addition, it has a ring structure formed by further condensation of an aromatic ring bonded to the sulfonic acid group of the anion, and has a structural feature of another aromatic ring structure containing a bulky substituent. Due to the steric hindrance between the two aromatic rings, the rotational freedom of the bonds connecting the aromatic rings is suppressed, so the excessive acid diffusion of the generated acid is limited. Furthermore, the onium salt of the present invention has sufficient fat solubility, so it is easy to manufacture and operate. By means of these effects, an acid with appropriate acid strength and controlled acid diffusion can be generated in the resist film, and a pattern with good resolution and small LER can be obtained even in a fine pattern. In a positive resist composition using an alkaline developer, a pattern with good rectangularity can be obtained by appropriate anti-solubility.

[0298] The photoacid generator as the component (B) is preferably an onium salt compound containing an anion represented by the following formula (B-2).

[0299] [Chemistry 68]

[0300]

[0301] In formula (B-2), n1 and n2 are each independently an integer of 0 to 2. When n2=0, n3 is an integer of 1 to 4, when n2=1, n3 is an integer of 1 to 6, and when n2=2, n3 is an integer of 1 to 8.

[0302] In formula (B-2), when n2=0, n4 is an integer of 0 to 3, when n2=1, n4 is an integer of 0 to 5, and when n2=2, n4 is an integer of 0 to 7. However, when n2=0, n3+n4 is 1 to 4, when n2=1, n3+n4 is 1 to 6, and when n2=2, n3+n4 is 1 to 8.

[0303] In formula (B-2), when n1=0, n5 is an integer of 1-5, when n1=1, n5 is an integer of 1-7, and when n1=2, n5 is an integer of 1-9.

[0304] In formula (B-2), R 21 , each independently an iodine atom, or a branched or cyclic hydrocarbon group having 3 to 20 carbon atoms which may contain a hetero atom, at least one R 21 , is the same as L 11 Specific examples of the aforementioned hydrocarbon group include branched alkyl groups 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 saturated hydrocarbon groups having 3 to 20 carbon atoms, such as decyl and adamantyl; aromatic groups such as phenyl, naphthyl, anthracenyl; groups obtained by combining them, etc., but are not limited to these. In addition, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., as a result, hydroxyl groups, cyano groups, halogen atoms, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may also be included. As for the aforementioned halogen atoms, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc. may be listed, and fluorine atoms or iodine atoms are preferred. When n5 is 2 or more, each R 21 , may be the same as or different from each other.

[0305] When n5 is 2 or more, multiple R 21 , and may also be bonded to each other and form a ring together with these bonded carbon atoms. As for the aforementioned ring, it is preferably a 5- to 8-membered ring.

[0306] In formula (B-2), R21 The following structures can be cited as examples of structures formed by bonding of L and aromatic rings, but are not limited to these. 11 of atomic bonds.

[0307] [Chemistry 69]

[0308]

[0309] [Chemistry 70]

[0310]

[0311] [Chemistry 71]

[0312]

[0313] [Chemistry 72]

[0314]

[0315] [Chemistry 73]

[0316]

[0317] [Chemistry 74]

[0318]

[0319] [Chemistry 75]

[0320]

[0321] In formula (B-2), R 22 , each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may also contain heteroatoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 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 20 carbon atoms, such as decyl, adamantyl, and adamantylmethyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and anthracenyl. 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, and halogen atoms, and part of the -CH2- of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in hydroxyl groups, cyano groups, halogen 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. As for the aforementioned halogen atoms, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, and the like are listed, and fluorine atoms or iodine atoms are preferred. When n4 is 2 or more, each R 22 , may be the same as or different from each other.

[0322] When n4 is 2 or more, multiple R 22 , and may also be bonded to each other and form a ring together with these bonded carbon atoms. As for the aforementioned ring, it is preferably a 5- to 8-membered ring.

[0323] In formula (B-2), R F1 , each independently represents 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 For example, fluorine atom, trifluoromethyl, difluoromethyl, trifluoromethoxy, difluoromethoxy, trifluoromethylthio or difluoromethylthio is preferred, and fluorine atom, trifluoromethyl or trifluoromethoxy is more preferred. By including fluorine atom, the acid strength of the generated acid is increased, so the deprotection reaction proceeds smoothly. When n3 is 2 or more, each R F1 , may be the same as or different from each other.

[0324] In formula (B-2), L 11 and L 12 , each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond or a carbamate bond. Among them, an ether bond, an ester bond or a sulfonate bond is preferred, and an ether bond or a sulfonate bond is more preferred.

[0325] In formula (B-2), X L , is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom. The aforementioned alkylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl, cyclic saturated alkylene, etc. Specific examples of the aforementioned hetero atom include oxygen atom, nitrogen atom, sulfur atom, etc.

[0326] Just X L Specific examples of the alkylene group having 1 to 40 carbon atoms which may contain a hetero atom and represented by may include the following, but are not limited to these. 11and L 12 of atomic bonds.

[0327] [Chemistry 76]

[0328]

[0329] [Chemistry 77]

[0330]

[0331] [Chemistry 78]

[0332]

[0333] [Chemistry 79]

[0334]

[0335] Among these, X L -0~X L -22 and X L -47~X L -58.

[0336] The acid generator represented by the formula (B-2) is preferably one represented by the following formula (B-2-1).

[0337] [Chemistry 80]

[0338]

[0339] In the formula, n1~n5, R 21 , R 22 , R F1 , L 11 and X L , the same as above.

[0340] Specific examples of the anion represented by formula (B-2) include those shown below, but are not limited to these.

[0341] [Chemistry 81]

[0342]

[0343] [Chemistry 82]

[0344]

[0345] [Chemistry 83]

[0346]

[0347] [Chemistry 84]

[0348]

[0349] [Chemistry 85]

[0350]

[0351] [Chemistry 86]

[0352]

[0353] [Chemistry 87]

[0354]

[0355] [Chemistry 88]

[0356]

[0357] [Chemistry 89]

[0358]

[0359] [Chemistry 90]

[0360]

[0361] [Chemistry 91]

[0362]

[0363] [Chemistry 92]

[0364]

[0365] [Chemistry 93]

[0366]

[0367] [Chemistry 94]

[0368]

[0369] [Chemistry 95]

[0370]

[0371] [Chemistry 96]

[0372]

[0373] [Chemistry 97]

[0374]

[0375] [Chemistry 98]

[0376]

[0377] [Chemistry 99]

[0378]

[0379] [Chemical 100]

[0380]

[0381] [Chemistry 101]

[0382]

[0383] [Chemistry 102]

[0384]

[0385] [Chemistry 103]

[0386]

[0387] [Chemistry 104]

[0388]

[0389] [Chemistry 105]

[0390]

[0391] [Chemistry 106]

[0392]

[0393] [Chemistry 107]

[0394]

[0395] [Chemistry 108]

[0396]

[0397] [Chemistry 109]

[0398]

[0399] [Chemistry 110]

[0400]

[0401] [Chemistry 111]

[0402]

[0403] [Chemistry 112]

[0404]

[0405] The photoacid generator as the component (B) is preferably an onium salt compound containing an anion represented by the following formula (B-3).

[0406] [Chemistry 113]

[0407]

[0408] In formula (B-3), p is 1, 2 or 3. q is an integer of 1 to 5. r is an integer of 0 to 3. s1 is 0 or 1.

[0409] In formula (B-3), L 21 , is a single bond, an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond.

[0410] In formula (B-3), L 22 , is an ether bond, an ester bond, a sulfonate bond, a carbonate bond or a carbamate bond.

[0411] In formula (B-3), when p is 1, L 23 is a single bond or an alkylene group having 1 to 20 carbon atoms, and when p is 2 or 3, L 23 It is a (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms. The alkylene group and the (p+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.

[0412] L 23 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 alkane diyl groups having 1 to 20 carbon atoms, such as methane diyl, 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 cyclopentane diyl, cyclohexane diyl, norbornane diyl, and adamantane diyl; 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. 23 The (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include groups obtained by removing one or two hydrogen atoms from the above-mentioned specific examples of the hydrocarbon group having 1 to 20 carbon atoms.

[0413] In formula (B-3), Rf 1and Rf 2 , are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group.

[0414] In formula (B-3), R 31 , 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 31A )(R 31B )、-N(R 31C )-C(=O)-R 31D or -N(R 31C )-C(=O)-OR 31D . R 31A and R 31B , each independently represents a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. 31C , is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. 31D , is a saturated hydrocarbon group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 8 carbon atoms.

[0415] R 31 , R 31A , R 31B and R 31C The saturated hydrocarbon group having 1 to 6 carbon atoms represented by may be straight-chain, branched, or cyclic. 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. 31 The saturated hydrocarbon portion of the saturated hydrocarbonoxy group having 1 to 6 carbon atoms represented by may be the same as the specific examples of the saturated hydrocarbon group described above. 31 The saturated hydrocarbon 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.

[0416] R 31D The unsaturated aliphatic hydrocarbon group having 2 to 8 carbon atoms represented may be straight chain, branched or cyclic. Specific examples thereof include alkenyl groups having 2 to 8 carbon atoms such as ethenyl, propenyl, butenyl and hexenyl; alkynyl groups having 2 to 8 carbon atoms such as ethynyl, propynyl and butynyl; and cyclic unsaturated aliphatic hydrocarbon groups having 3 to 8 carbon atoms such as cyclohexenyl and norbornene.

[0417] In formula (B-3), R 32, is a saturated alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 20 carbon atoms, a part or all of the hydrogen atoms of the saturated alkylene group may be substituted by halogen atoms other than fluorine atoms, and a part or all of the hydrogen atoms of the arylene group may be substituted by a substituent selected from a saturated alkyl group having 1 to 20 carbon atoms, a saturated alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogen atom and a hydroxyl group.

[0418] R 32 The alkylene group having 1 to 20 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. 23 The same as those exemplified for the alkylene group having 1 to 20 carbon atoms.

[0419] Just R 32 Specific examples of the arylene group having 6 to 20 carbon atoms include phenylene, naphthylene, phenanthrenediyl, anthracenediyl, etc. The saturated hydrocarbon group having 1 to 20 carbon atoms and the hydrocarbon part of the hydrocarbonoxy group having 1 to 20 carbon atoms as a substituent of the arylene group may be straight chain, branched chain, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecanyl, tridecyl, tetradecyl, pentadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl; and cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl. Specific examples of the arylene group having 6 to 14 carbon atoms as a substituent of the arylene group include a phenylene group, a naphthylene group, a phenanthrenediyl group, an anthracenediyl group, and the like.

[0420] The anion represented by the formula (B-3) is preferably an anion represented by the following formula (B-3-1).

[0421] [Chemistry 114]

[0422]

[0423] In formula (B-3-1), p, q, r, L 21 , L 23 and R 31 , the same as above. s2, is an integer from 1 to 4. R 32A , 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. When s2 is 2 to 4, each R 32A , may be the same as or different from each other.

[0424] Examples of the anion represented by the formula (B-3) include the following, but are not limited to these.

[0425] [Chemistry 115]

[0426]

[0427] [Chemistry 116]

[0428]

[0429] [Chemistry 117]

[0430]

[0431] [Chemistry 118]

[0432]

[0433] [Chemistry 119]

[0434]

[0435] [Chemistry 120]

[0436]

[0437] [Chemistry 121]

[0438]

[0439] [Chemistry 122]

[0440]

[0441] [Chemistry 123]

[0442]

[0443] [Chemistry 124]

[0444]

[0445] [Chemistry 125]

[0446]

[0447] [Chemistry 126]

[0448]

[0449] [Chemistry 127]

[0450]

[0451] [Chemistry 128]

[0452]

[0453] [Chemistry 129]

[0454]

[0455] [Chemistry 130]

[0456]

[0457] [Chemistry 131]

[0458]

[0459] [Chemistry 132]

[0460]

[0461] [Chemistry 133]

[0462]

[0463] [Chemistry 134]

[0464]

[0465] [Chemistry 135]

[0466]

[0467] [Chemistry 136]

[0468]

[0469] [Chemistry 137]

[0470]

[0471] [Chemistry 138]

[0472]

[0473] [Chemistry 139]

[0474]

[0475] [Chemistry 140]

[0476]

[0477] [Chemistry 141]

[0478]

[0479] [Chemistry 142]

[0480]

[0481] The counter cation of the anion of the onium salt is preferably a sulfonium cation represented by the following formula (B-4) or an iodonium cation represented by the following formula (B-5).

[0482] [Chemistry 143]

[0483]

[0484] In formula (B-4) and (B-5), R 41 ~R 45 , are each independently a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom.

[0485] Just R 41 ~R 45 Examples of the halogen atom represented by include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0486] R 41 ~R 45 The hydrocarbon group having 1 to 20 carbon atoms represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 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 20 carbon atoms, such as decyl, adamantyl, and adamantylmethyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, naphthyl, and anthracenyl; groups obtained by combining them, etc. 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, and halogen atoms, and part of -CH2- of the aforementioned hydrocarbon groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl groups, etc. may also be included.

[0487] Again, R 41 and R 42 , and may be bonded to each other and form a ring together with these bonded sulfur atoms. As for the ring formed at this time, the following ones can be mentioned.

[0488] [Chemistry 144]

[0489]

[0490] In the formula, the dotted line is the 43 of atomic bonds.

[0491] Specific examples of the sulfonium cation represented by the formula (B-4) include those shown below, but are not limited to these.

[0492] [Chemistry 145]

[0493]

[0494] [Chemistry 146]

[0495]

[0496] [Chemistry 147]

[0497]

[0498] [Chemistry 148]

[0499]

[0500] [Chemistry 149]

[0501]

[0502] [Chemistry 150]

[0503]

[0504] [Chemistry 151]

[0505]

[0506] [Chemistry 152]

[0507]

[0508] [Chemistry 153]

[0509]

[0510] [Chemistry 154]

[0511]

[0512] [Chemistry 155]

[0513]

[0514] [Chemistry 156]

[0515]

[0516] [Chemistry 157]

[0517]

[0518] [Chemistry 158]

[0519]

[0520] [Chemistry 159]

[0521]

[0522] [Chemistry 160]

[0523]

[0524] [Chemistry 161]

[0525]

[0526] [Chemistry 162]

[0527]

[0528] [Chemistry 163]

[0529]

[0530] [Chemistry 164]

[0531]

[0532] [Chemistry 165]

[0533]

[0534] [Chemistry 166]

[0535]

[0536] [Chemistry 167]

[0537]

[0538] [Chemistry 168]

[0539]

[0540] [Chemistry 169]

[0541]

[0542] [Chemistry 170]

[0543]

[0544] Specific examples of the iodonium cation represented by the formula (B-5) include those shown below, but are not limited to these.

[0545] [Chemistry 171]

[0546]

[0547] [Chemistry 172]

[0548]

[0549] Specific examples of the onium salt of the present invention include any combination of the above-mentioned anions and cations.

[0550] The acid generated by the photoacid generator preferably has a pKa of -3.0 or more, more preferably -1.0 or more. The upper limit of the pKa is preferably 2.0. The pKa value is calculated using pKa DB in the software ACD / Chemsketch ver: 9.04 manufactured by Advanced Chemistry Development, Inc.

[0551] In the chemically amplified positive resist composition of the present invention, the content of the photoacid generator (B) is preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, relative to 80 parts by weight of the base polymer (A). The photoacid generator (B) may be used alone or in combination of two or more.

[0552] [(C) Quencher]

[0553] The chemically amplified positive resist composition of the present invention includes a quencher (acid diffusion inhibitor). The quencher in the present invention is a material used to prevent the acid generated by the photoacid generator in the chemically amplified resist composition from diffusing toward the unexposed portion to form a desired pattern.

[0554] As for the above-mentioned quencher, known basic compounds can be cited. As for the known basic compounds, primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having carboxyl groups, nitrogen-containing compounds having sulfonyl groups, nitrogen-containing compounds having hydroxyl groups, nitrogen-containing compounds having hydroxyphenyl groups, alcoholic nitrogen-containing compounds, amides, imides, and carbamates can be cited. In particular, primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Publication No. 2008-111103, especially amine compounds having hydroxyl groups, ether bonds, ester bonds, lactone rings, cyano groups, and sulfonate ester bonds, or compounds having carbamate groups described in Japanese Patent No. 3790649 are 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.

[0555] In addition, as for the above-mentioned quencher, onium salts such as sulfonium salts, iodonium salts, and ammonium salts of carboxylic acids not fluorinated at the α-position described in Japanese Patent Application Laid-Open No. 2008-158339 can be cited. Sulfonic acid, imidic acid, or methide acid fluorinated at the α-position is necessary to deprotect the acid-labile group, and the carboxylic acid not fluorinated at the α-position is released by salt exchange with the onium salt not fluorinated at the α-position. The carboxylic acid not fluorinated at the α-position hardly undergoes deprotection reaction, so it can function as a quencher.

[0556] Examples of the onium salt of carboxylic acid not fluorinated at the α-position include those represented by the following formula (C1).

[0557] [Chemistry 173]

[0558]

[0559] In formula (C1), R 51 , is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom, but excludes a case where 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.

[0560] R 51 The 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, isobutyl, 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[5.2.1.02,6 ] 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.

[0561] 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, resulting in a hydroxyl group, a cyano group, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like. Examples of the hydrocarbon group containing a heteroatom 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.

[0562] In formula (C1), Mq A + , is an onium cation. As for the onium cation, it is preferably a sulfonium cation, an iodonium cation or an ammonium cation, and more preferably a sulfonium cation or an iodonium cation. As for specific examples of the sulfonium cation, the same ones as those exemplified as the sulfonium cation represented by formula (B-4) can be cited. As for specific examples of the iodonium cation, the same ones as those exemplified as the iodonium cation represented by formula (B-5) can be cited.

[0563] Examples of the anion of the onium salt represented by the formula (C1) include the following, but are not limited to these.

[0564] [Chemistry 174]

[0565]

[0566] [Chemistry 175]

[0567]

[0568] [Chemistry 176]

[0569]

[0570] As the quencher, a sulfonium salt of a carboxylic acid containing an iodinated benzene ring represented by the following formula (C2) can also be suitably used.

[0571] [Chemistry 177]

[0572]

[0573] In formula (C2), t is an integer of 1 to 5. u is an integer of 0 to 3. v is an integer of 1 to 3.

[0574] In formula (C2), R 61 , is a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbon group having 1 to 6 carbon atoms, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms, or a saturated hydrocarbon sulfonyloxy group having 1 to 4 carbon atoms, which may be partially or entirely substituted with halogen atoms, or -N(R 61A )-C(=O)-R 61B or -N(R 61A )-C(=O)-OR 61B . R 61A , is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms. 61B , is a saturated hydrocarbon group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbon group having 2 to 8 carbon atoms. When u and / or v are 2 or more, each R 61 They may be the same or different from each other.

[0575] In formula (C2), L 31 , is a single bond or a (v+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 aforementioned saturated hydrocarbon group, saturated hydrocarbon oxy group, saturated hydrocarbon carbonyloxy group, and saturated hydrocarbon sulfonyloxy group may be straight-chain, branched, or cyclic.

[0576] In formula (C2), R 62 , R 63 and R 64, 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 linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, and aralkyl groups having 7 to 20 carbon atoms. Furthermore, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a hydroxyl group, a carboxyl group, a halogen atom, an oxo group, a cyano group, a nitro group, a sultone ring, a sulfonic acid 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 62 and R 63 , and may also bond to each other and form a ring together with these bonded sulfur atoms.

[0577] Specific examples of the compound represented by formula (C2) include those described in Japanese Patent Application Laid-Open No. 2017-219836. The compound represented by formula (C2) has high absorption, high sensitization effect, and high acid diffusion suppression effect.

[0578] As the quencher, a nitrogen atom-containing carboxylate type compound represented by the following formula (C3) can also be used.

[0579] [Chemistry 178]

[0580]

[0581] In formula (C3), R 71 ~R 74 , each independently a hydrogen atom, -L 41 -CO2 - , or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 71 With R 72 , R 72 With R 73 , or R 73 With R 74 , may also be bonded to each other and form a ring together with these bonded carbon atoms. 41 , is a single bond or an alkylene group having 1 to 20 carbon atoms which may contain a hetero atom. 75 , is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom.

[0582] In formula (C3), ring R r , is a ring having 2 to 6 carbon atoms and a nitrogen atom in the formula, and part or all of the hydrogen atoms bonded to the carbon atoms of the ring may be replaced by a hydrocarbon group having 1 to 20 carbon atoms, or -L 41 -CO2 -The ring may be substituted, and part of the carbon atoms of the ring may be substituted by sulfur atoms, oxygen atoms or nitrogen atoms. The aforementioned ring may be an alicyclic ring or an aromatic ring, and preferably a 5-membered ring or a 6-membered ring. 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 and the like.

[0583] The carboxylic acid onium salt represented by formula (C3) has at least one -L 41 -CO2 - That is, R 61 ~R 64 At least one of them is -L 41 -CO2 - , and / or and ring R r At least one of the hydrogen atoms bonded to the carbon atom is replaced by -L 41 -CO2 - Replacer.

[0584] In formula (C3), Mq B + , is a sulfonium cation, an iodonium cation or an ammonium cation, preferably a sulfonium cation. Specific examples of the sulfonium cation include the same ones as those exemplified for the sulfonium cation represented by formula (B-4).

[0585] Examples of the anion of the compound represented by the formula (C3) include the following, but are not limited to these.

[0586] [Chemistry 179]

[0587]

[0588] [Chemistry 180]

[0589]

[0590] [Chemistry 181]

[0591]

[0592] [Chemistry 182]

[0593]

[0594] [Chemistry 183]

[0595]

[0596] [Chemistry 184]

[0597]

[0598] Furthermore, as the quencher, a weakly acidic betaine-type compound may also be used. Specific examples thereof include those shown below, but are not limited thereto.

[0599] [Chemistry 185]

[0600]

[0601] As for the aforementioned quencher, a polymer quencher described in Japanese Patent Application Publication No. 2008-239918 can be further cited. The polymer quencher improves the rectangularity of the resist pattern by being aligned on the surface of the resist film. The polymer quencher also has the effect of preventing film loss and doming of the pattern when a protective film for wet exposure is used.

[0602] In the chemically amplified positive resist composition of the present invention, the content of the quencher (C) is preferably 0.01 to 50 parts by weight, more preferably 0.1 to 30 parts by weight, relative to 80 parts by weight of the base polymer (A). The quencher (C) may be used alone or in combination of two or more.

[0603] In the chemically amplified positive resist composition of the present invention, the content ratio of the photoacid generator to the quencher ((B) / (C)) is less than 3, preferably less than 2.5, and more preferably less than 2 in terms of mass ratio. If the content ratio of the photoacid generator to the quencher contained in the chemically amplified positive resist composition of the present invention falls within the above range, acid diffusion can be sufficiently suppressed, and a pattern shape with excellent resolution and size uniformity can be obtained, especially in EB lithography which is easily affected by forward scattering and backward scattering.

[0604] [(D) Fluorine-containing polymer]

[0605] The chemically amplified positive resist composition of the present invention may contain a fluorine atom-containing polymer for the purpose of achieving high contrast, suppressing chemical flare of acid during high-energy ray irradiation, shielding mixing of acid from the antistatic film during the process of coating the antistatic film material on the resist film, and suppressing undesired and unnecessary pattern degradation. The 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 polymer containing fluorine atoms also has the function of a surfactant, so it can prevent insoluble matter that may be generated during the development process from adhering to the substrate again, and it will also have an effect on development defects.

[0606] [Chemistry 186]

[0607]

[0608] In formulas (D1) to (D6), x is 1, 2 or 3. y is an integer satisfying 0≤y≤5+2z-x. z is 0 or 1. k is 1, 2 or 3. R B , are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. C , each independently a hydrogen atom or a methyl group. 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. 103 , R 106 , R 107 and R 108 , each independently a hydrogen atom, a hydrocarbon group having 1 to 15 carbon atoms, a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group, R 103 , R 106 , R 107 and R 108 When it is a hydrocarbon group or a fluorinated hydrocarbon group, the carbon-carbon bond may be separated by an ether bond or a carbonyl group. 109 , is a hydrogen atom or a linear or branched hydrocarbon group having 1 to 5 carbon atoms, which may be separated by a heteroatom-containing group between carbon-carbon bonds. 110 , is a linear or branched hydrocarbon group having 1 to 5 carbon atoms, wherein a heteroatom-containing group may be present between carbon-carbon bonds. 111, is a saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted by a fluorine atom, and a portion of the -CH2- in the saturated hydrocarbon group may be substituted by an ester bond or an ether bond. 1 , is a (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. 2 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-. 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. 32 , is a single bond, ester bond, ether bond or sulfonamide bond. * is an atomic bond to a carbon atom of the main chain.

[0609] In formula (D1) and (D2), R 101 , R 102 , R 104 and R 105 The saturated hydrocarbon group having 1 to 10 carbon atoms represented by may be straight-chain, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl; and cyclic saturated hydrocarbon groups having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl and norbornyl. Among these, saturated hydrocarbon groups having 1 to 6 carbon atoms are preferred.

[0610] 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 may be 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, alkynyl groups having 2 to 15 carbon atoms, etc., preferably alkyl groups having 1 to 15 carbon atoms. As for the aforementioned alkyl 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, n-pentadecyl, etc. may be mentioned. In addition, as for the fluorinated hydrocarbon groups, groups in which a part or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon groups are substituted with fluorine atoms may be mentioned.

[0611] In formula (D4), Z 1The (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms represented by , includes a group obtained by excluding 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 As for the (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by , there can be mentioned a group in which at least one hydrogen atom of the (k+1)-valent hydrocarbon group is substituted with a fluorine atom.

[0612] Specific examples of repeating units D1 to D4 include those shown below, but are not limited to these. B , the same as above.

[0613] [Chemistry 187]

[0614]

[0615] [Chemistry 188]

[0616]

[0617] [Chemistry 189]

[0618]

[0619] In formula (D5), R 109 and R 110 As for the hydrocarbon group having 1 to 5 carbon atoms represented by , alkyl, alkenyl, alkynyl, etc. can be mentioned, and alkyl is preferred. As for the aforementioned alkyl, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, etc. can be mentioned. In addition, the carbon-carbon bonds of the aforementioned hydrocarbon groups may be separated by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms.

[0620] In formula (D5), -OR 109 Preferably, it is a hydrophilic group. In this case, R 109 Preferred are hydrogen atoms, alkyl groups having 1 to 5 carbon atoms with an oxygen atom between carbon-carbon bonds, and the like.

[0621] In formula (D5), Z 2 , preferably *-C(=O)-O- or *-C(=O)-NH-. Furthermore, R C Preferably, it is methyl. 2 If there is a carbonyl group in the antistatic film, the acid capture ability from the antistatic film will be improved. C If the group is a methyl group, it will become a rigid 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 improved, and the resolution and pattern shape will not be deteriorated.

[0622] The repeating unit D5 includes the following, but is not limited thereto.C , the same as above.

[0623] [Chemistry 190]

[0624]

[0625] [Chemistry 191]

[0626]

[0627] In formula (D6), Z 3 The saturated alkylene group having 1 to 10 carbon atoms may be straight-chain, branched or cyclic. 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 and 1,1-dimethylethane-1,2-diyl.

[0628] In formula (D6), R 111 The saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is replaced by a fluorine atom may be straight-chain, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms or cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms in which at least one hydrogen atom is replaced by a fluorine atom.

[0629] The repeating unit D6 includes the following, but is not limited thereto. C , the same as above.

[0630] [Chemistry 192]

[0631]

[0632] [Chemistry 193]

[0633]

[0634] [Chemistry 194]

[0635]

[0636] [Chemistry 195]

[0637]

[0638] 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.

[0639] The aforementioned fluorine-containing polymer may also contain other repeating units other than the aforementioned repeating units. As for such repeating units, examples include those described in paragraphs

[0046] to

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

[0640] The fluorine-containing polymer can be synthesized by copolymerizing monomers protected by protecting groups as required, and then performing a deprotection reaction as required by a known method. The copolymerization reaction is not particularly limited, and is preferably free radical polymerization or anionic polymerization. For the method, reference can be made to Japanese Patent Publication No. 2004-115630.

[0641] The Mw of the aforementioned fluorine-containing polymer is preferably 2000 to 50000, more preferably 3000 to 20000. If the Mw is less than 2000, the diffusion of the acid will be promoted, and the resolution will be degraded and the stability over time will be impaired. If the Mw is too large, the solubility in the solvent will decrease, and coating defects may occur. In addition, for the aforementioned fluorine-containing polymer, the Mw / Mn is preferably 1.0 to 2.2, more preferably 1.0 to 1.7.

[0642] 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, and even more preferably 0.5 to 10 parts by mass relative to 80 parts by mass of the base polymer (A). The fluorine-containing polymer (D) may be used alone or in combination of two or more.

[0643] [(E) Organic solvent]

[0644] The chemically amplified positive resist composition of the present invention may also contain an organic solvent. As for the aforementioned organic solvent, there is no particular limitation as long as it can dissolve each component. As for such an organic solvent, for example, ketones such as cyclopentanone, cyclohexanone, methyl-2-n-pentanone, and 2-heptanone described in paragraphs

[0144] to

[0145] of Japanese Patent Publication No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether (PGME) , 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, 3-methoxypropionic acid methyl ester, 3-ethoxypropionic acid ethyl ester, tert-butyl acetate, tert-butyl propionate, propylene glycol monotert-butyl ether acetate and other esters; γ-butyrolactone and other lactones; their mixed solvents, etc. When using an acetal-based acid-labile group, in order to accelerate the deprotection reaction of the acetal, a high-boiling alcohol solvent may also be added, specifically diethylene glycol, propylene glycol, glycerol, 1,4-butanediol, 1,3-butanediol and the like.

[0645] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, and a mixed solvent thereof are preferred.

[0646] When the chemically amplified positive resist composition of the present invention contains (E) 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 (A). The organic solvent (E) may be used alone or in combination of two or more.

[0647] [(F) Surfactant]

[0648] The chemically amplified positive resist composition of the present invention may also contain a conventional surfactant as the component (F) in order to improve the coating properties on the substrate. Regarding the aforementioned surfactant, a large number of examples are recorded in Japanese Patent Gazette No. 2004-115630 and most of them are well known, and these can be used as references and selected. When the chemically amplified positive resist composition of the present invention contains the (F) surfactant, its content is preferably 0 to 5 parts by mass relative to 80 parts by mass of the (A) base polymer. The aforementioned surfactant may be used alone or in combination of two or more. Furthermore, when the chemically amplified positive resist composition of the present invention contains the aforementioned fluorine atom-containing polymer, the aforementioned fluorine atom-containing polymer will also play the role of a surfactant, so the aforementioned surfactant may not be included.

[0649] The chemically amplified positive resist composition of the present invention can be prepared by dissolving components (A) to (C) and components (D) and (F) as needed in an organic solvent of component (E) simultaneously or in any order to form a uniform resist solution. The obtained resist solution is preferably filtered. By using nylon or polyethylene (PE) as a filter for filtration, the colloidal components and particles contained in the aforementioned resist solution can be effectively removed. In addition, the aforementioned filter is preferably used with a pore size of 20 nm or less in order to maintain the quality of the advanced generation.

[0650] In terms of the design of the chemically amplified positive resist composition of the present invention, the dissolution rate of the exposed part of the obtained resist film in the alkaline developer is preferably 50 nm / sec or more, and more preferably 80 nm / sec or more, from the perspective of improving the development load. By being 50 nm / sec or more, even if there are differences in the pattern layout in the dense and sparse patterns, it can still be uniformly dissolved in the alkaline developer, and the line width variation can be reduced. In addition, the exposure part dissolution rate in the present invention is a value calculated by using a resist development analyzer to calculate the film loss amount when developing with a 2.38 mass % TMAH aqueous solution at 23°C after spin coating the chemically amplified positive resist composition of the present invention on an 8-inch silicon wafer, baking at 110°C for 60 seconds to form a resist film with a film thickness of 90 nm, exposing with a KrF excimer laser with an amount of energy that terminates the deprotection reaction of the polymer, baking at 110°C for 60 seconds, and using a resist development analyzer.

[0651] Furthermore, the dissolution rate of the unexposed part of the resist film obtained by the chemically amplified positive resist composition of the present invention to the alkaline developer is preferably 10 nm / min or less, more preferably 9 nm / min or less, and even more preferably 8 nm / min or less. When the resist film is a thin film region (less than 100 nm), the influence of the pattern film loss by the alkaline developer becomes greater. When the dissolution rate of the unexposed part is greater than 10 nm / min, the pattern collapses and it becomes impossible to form a fine pattern. In particular, when a photomask required to be defect-free is produced, the development process has a strong tendency, so it is significant. Moreover, the dissolution rate of the unexposed part is a value calculated from the film loss amount when a 6-inch silicon wafer is spin-coated with the chemically amplified positive resist composition of the present invention, baked at 110°C for 240 seconds to form a resist film with a film thickness of 80 nm, and then developed at 23°C for 80 seconds with a 2.38 mass % TMAH aqueous solution.

[0652] [Resist pattern forming method]

[0653] The resist pattern forming method of the present invention comprises the following steps: forming a resist film on a substrate using the aforementioned chemically amplified positive resist composition, irradiating the aforementioned resist film with a pattern using EUV or EB, especially EB (i.e., exposing the aforementioned resist film using EUV or EB), and developing the resist film irradiated with the aforementioned pattern using an alkaline developer.

[0654] As for the aforementioned substrate, for example, a substrate for integrated circuit manufacturing (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflection film, etc.), or a substrate for transmission or reflection mask circuit manufacturing (Cr, CrO, CrON, MoSi2, Si, SiO, SiO2, SiON, SiONC, CoTa, NiTa, TaBN, SnO2, etc.) can be used. On the aforementioned substrate, the aforementioned chemically amplified positive resist composition is applied by spin coating or the like to make the film thickness 0.03 to 2 μm, and the substrate is placed on a hot plate and pre-baked preferably at 60 to 150° C. for 1 to 20 minutes, more preferably at 80 to 140° C. for 1 to 10 minutes to form a resist film.

[0655] Then, the resist film is exposed using EUV or EB, and the pattern is irradiated. When EB is used, the energy of EB is irradiated so that the exposure amount becomes 10 to 500 μC / cm in order to form the target pattern. 2 , preferably 50 to 400 μC / cm 2 .

[0656] For exposure, in addition to the usual exposure method, an immersion method in which the space between the mask and the resist film is wetted may be used as appropriate. In this case, a water-insoluble protective film may also be used.

[0657] Then, a post-exposure bake (PEB) is performed on a hot plate at preferably 60-150° C. for 1-20 minutes, more preferably 80-140° C. for 1-10 minutes.

[0658] Thereafter, a developer containing 0.1 to 5% by mass, preferably 2 to 3% by mass, of an alkaline aqueous solution of TMAH is used to carry out development for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, by conventional methods such as dipping, puddle, and spraying to form a target pattern on the substrate.

[0659] The chemically amplified positive resist composition of the present invention is particularly useful for forming patterns with good resolution and low LER. The chemically amplified positive resist composition of the present invention is particularly useful for pattern formation on substrates with a material on the surface that is difficult to adhere to the resist pattern and is prone to pattern peeling and pattern collapse. Examples of such substrates include substrates with a metal chromium or a chromium compound containing one or more light elements selected from oxygen, nitrogen and carbon sputtered on the outermost surface, and a substrate with a outermost layer containing SiO, SiO x , tantalum compounds, molybdenum compounds, cobalt compounds, nickel compounds, tungsten compounds, tin compounds, etc. The chemically amplified positive resist composition of the present invention is particularly useful when a blank photomask is used as a substrate for pattern formation. In this case, the blank photomask can be either a transmissive or reflective type.

[0660] Regarding the transmission type blank photomask, the blank photomask having a light shielding film made of a chromium-based material may be a blank photomask for a binary mask or a blank photomask for a phase shift mask. In the case of a blank photomask for a binary mask, it may be a blank photomask having an anti-reflection layer and a light shielding layer made of a chromium-based material as a light shielding film, or it may be a blank photomask in which the entire anti-reflection film on the surface side or only the more surface side of the anti-reflection film on the surface side is made of a chromium-based material, and the remaining part is made of, for example, a silicon-based compound material that may also contain a transition metal. In the case of a blank photomask for a phase shift mask, a blank photomask for a phase shift mask having a chromium-based light shielding film on the phase shift film may be used as an object.

[0661] The aforementioned blank photomask having a chromium-based material as the outermost layer is a well-known one as exemplified by the current technology in Japanese Patent Publication No. 2008-26500, Japanese Patent Publication No. 2007-302873 or any of these, and a detailed description thereof is omitted. However, in the case of, for example, a light-shielding film having an anti-reflection layer and a light-shielding layer formed using a chromium-based material, a film structure as described below can be used.

[0662] When a light-shielding film having an anti-reflection layer and a light-shielding layer is formed using a chromium-based material, the layer composition may be stacked in the order of the anti-reflection layer and the light-shielding layer from the surface side, or in the order of the anti-reflection layer, the light-shielding layer, and the anti-reflection layer. In addition, the anti-reflection layer and the light-shielding layer may each be a plurality of layers, and the composition may be changed discontinuously or continuously between layers with different compositions. As for the chromium-based material used, metal chromium and a material containing light elements such as oxygen, nitrogen, and carbon in metal chromium are used. Specifically, metal chromium, chromium oxide, chromium nitride, chromium carbide, chromium oxide nitride, chromium oxide carbide, chromium nitride carbide, chromium oxide nitride carbide, chromium oxide nitride carbide, and chromium oxide nitride carbide.

[0663] A reflective mask blank includes: a substrate; a multilayer reflective film formed on one main surface (front side) of the substrate, specifically, a multilayer reflective film that reflects exposure light such as EUV light; and an absorber film formed on the multilayer reflective film, specifically, an absorber film that absorbs exposure light such as EUV light and reduces reflectivity. A reflective mask (reflective mask for EUV) having an absorber pattern (absorber film pattern) formed by patterning the absorber film is manufactured from the reflective mask blank (reflective mask blank for EUV). The wavelength of EUV light used in EUV lithography is 13 to 14 nm, and is usually light with a wavelength of about 13.5 nm.

[0664] The multilayer reflective film is usually preferably provided in contact with one main surface of the substrate. If the effect of the present invention is not lost, a base film may be provided between the substrate and the multilayer reflective film. The absorber film may be formed in contact with the multilayer reflective film, or a protective film (protective film of the multilayer reflective film) may be provided between the multilayer reflective film and the absorber film, preferably in contact with the multilayer reflective film, and more preferably in contact with the multilayer reflective film and the absorber film. The protective film is used to protect the multilayer reflective film during processing such as cleaning and correction. In addition, the protective film preferably has the effect of protecting the multilayer reflective film when patterning is performed by etching the absorber film and preventing oxidation of the multilayer reflective film. On the other hand, a conductive film used for electrostatically clamping the reflective mask in the exposure device may be provided under one main surface of the substrate and the other main surface (back side) of the opposite side so as to be in contact with the other main surface. Moreover, here, one main surface of the substrate is set as the surface and the upper side of the front side, and the other main surface is set as the back side and the lower side. The front and back and the top and bottom of the two are determined for convenience. One main surface and the other main surface are any of the two main surfaces (film forming surfaces) in the substrate, and the front and back and the top and bottom can be replaced. More specifically, it can be formed using a method such as Japanese Patent Publication No. 2021-139970 or those exemplified as current technologies.

[0665] By using the resist pattern forming method of the present invention, even when using a substrate whose outermost surface is made of a material that is easily affected by the shape of the resist pattern, such as a material containing chromium, silicon or tantalum (for example, a transmission or reflection type blank mask), high resolution can still be obtained, and the influence of development load and residue defects is suppressed, and the pattern has small dimensional differences and is not dependent on pattern density.

[0666] Example

[0667] The present invention is specifically described below by showing synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples. The copolymerization composition ratio is a molar ratio, and Mw is a polystyrene-equivalent weight average molecular weight measured by GPC.

[0668] [1] Synthesis of polymers

[0669] [Synthesis Example] Synthesis of Polymer P-1

[0670] In a 200 mL flask, 20 g of polyhydroxystyrene-acenaphthylene copolymer and 180 g of THF as a solvent were added. In the reaction solution, 12 g of triethylamine was added under a nitrogen atmosphere at about 25°C, and then 19 g of the acetalizing agent Ac-1 represented by the following formula was dripped in over 30 minutes, and the reaction was carried out at room temperature for 3 hours. After the reaction was completed, 12 g of acetic acid was added, and the obtained reaction solution was dripped into 500 g of hexane, and the precipitated copolymer was filtered. The filtered copolymer was washed twice with 120 g of hexane. The obtained copolymer was dissolved in a mixed solvent of 60 g of ethyl acetate and 20 g of water, and the obtained solution was transferred to a separatory funnel and washed and separated. After the organic layer after separation was concentrated, it was dissolved in 40 g of acetone, and the obtained solution was dripped into 600 g of water, and the obtained precipitate was filtered, washed with water, and dried to obtain 20.8 g of the target polymer P-1 which was a white polymer. The polymer P-1 is 13 C-NMR, 1 The following analysis results were obtained by H-NMR and GPC measurements.

[0671] [Chemistry 196]

[0672]

[0673] [Chemistry 197]

[0674]

[0675] In addition, except for changing the types and blending ratios of the monomers, the following polymers P-2 to P-19, comparative polymers cP-1 to cP-5 and AP-1 to AP-5 were synthesized in the same manner as the above-mentioned synthesis examples and known methods.

[0676] [Chemistry 198]

[0677]

[0678] [Chemistry 199]

[0679]

[0680] [Chemistry 200]

[0681]

[0682] [Chemistry 201]

[0683]

[0684] [Chemistry 202]

[0685]

[0686] [Chemistry 203]

[0687]

[0688] [Chemistry 204]

[0689]

[0690] The dissolution rate of the above-mentioned polymer in the alkaline developer was calculated by spin coating a polymer solution (polymer concentration: 16.7% by mass, solvent: PGMEA) on an 8-inch silicon wafer, baking at 100°C for 90 seconds to form a film with a thickness of 1000 nm, and then developing with a 2.38% by mass TMAH aqueous solution at 23°C for 100 seconds to measure the film loss. The results showed that the dissolution rates of P-1 to P-19, AP-1 to AP-5, and cP-1 to cP-4 were less than 5 nm / min, and the dissolution rate of cP-5 was 14 nm / min.

[0691] [2] Preparation of chemically amplified positive resist composition

[0692] [Examples 1-1 to 1-41, Comparative Examples 1-1 to 1-5]

[0693] The chemically amplified positive resist composition was prepared by dissolving each component in an organic solvent using the composition shown in Tables 1 to 3 below, and filtering the obtained solution through a 5 nm nylon filter and a 1 nm UPE filter. The organic solvent was a mixed solvent of 940 parts by mass of PGMEA, 1870 parts by mass of EL, and 1870 parts by mass of PGME.

[0694] The dissolution rate of the resist composition in the alkaline developer was calculated by measuring the film loss after spin coating on an 8-inch silicon wafer and baking at 110° C. for 240 seconds to form a resist film with a film thickness of 80 nm, and then developing with a 2.38 mass % TMAH aqueous solution at 23° C. for 80 seconds. The results showed that the dissolution rate of the resist film obtained from the resist compositions R-1 to R-41 and CR-1 to CR-5 was 10 nm / min or less, and the dissolution rate of the resist film obtained from the resist composition CR-6 was 16 nm / min.

[0695] [Table 1]

[0696]

[0697]

[0698] [Table 2]

[0699]

[0700]

[0701] [Table 3]

[0702]

[0703] In Tables 1 to 3, the structures of the photoacid generators PAG-1 to PAG-6, the quenchers Q-1 to Q-4, and the fluorine-containing polymers FP-1 to FP-5 are as follows.

[0704] [Chemistry 205]

[0705]

[0706] [Chemistry 206]

[0707]

[0708] [Chemistry 207]

[0709]

[0710] [3]EB Lithography Evaluation

[0711] [Examples 2-1 to 2-41, Comparative Examples 2-1 to 2-5]

[0712] Each chemically amplified positive resist composition (R-1 to R-41, CR-1 to CR-5) was spin-coated on a blank mask as a reflective blank mask for EUV exposure mask using ACT-M (manufactured by Tokyo Electron Co., Ltd.), and pre-baked on a hot plate at 110° C. for 600 seconds to prepare a resist film with a film thickness of 80 nm. The blank mask was a 6-inch low thermal expansion glass substrate on which a 40-layer multilayer reflective film of Mo / Si with a film thickness of 284 nm was formed, a Ru film with a film thickness of 3.5 nm was formed as a protective film, a TaN film with a film thickness of 70 nm was formed as an absorption layer, and a CrN film with a film thickness of 6 nm was formed as a hard mask. 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 from the outer periphery to the inner side of 10 mm, and the average film thickness and the film thickness range were calculated.

[0713] The resist film was exposed using an EB exposure apparatus (EBM-5000plus manufactured by Nuflare Technology Co., Ltd., accelerating voltage 50 kV), subjected to PEB at 110° C. for 600 seconds, and developed with a 2.38 mass % TMAH aqueous solution to obtain a positive pattern.

[0714] The obtained resist pattern was evaluated as follows. The blank mask with the pattern produced was observed by an empty SEM (scanning electron microscope), and the exposure amount with a 1:1 line and space (LS) resolution of 200 nm was defined as the optimum exposure amount (μC / cm 2 ), the minimum size in the exposure amount resolved at 1:1 was defined as the resolution (limiting resolution), and the LER of 200nmLS was measured by SEM. The pattern shape was visually determined to be rectangular. The results are shown in Tables 4 to 6.

[0715] [Table 4]

[0716]

[0717]

[0718] [Table 5]

[0719]

[0720] [Table 6]

[0721]

[0722] [4] Residue defect evaluation

[0723] [Examples 3-1 to 3-8, Comparative Examples 3-1 to 3-2]

[0724] The resist compositions (R-8, R-15 to R-20, R-33, CR-4, CR-5) were applied to a reflective blank mask for EUV exposure mask in the same manner as described above to form a resist film with a film thickness of 80 nm, and an EB exposure device (EBM-5000plus manufactured by Nuflare Technology Co., Ltd., accelerating voltage 50 kV) was used to draw the entire surface of the resist film with the optimal exposure amount of each resist composition, and PEB was performed at 110° C. for 600 seconds, and developed with a 2.38 mass % TMAH aqueous solution, and the development residue was evaluated using a mask defect inspection device (M9650 manufactured by Lasertec Co., Ltd.). The total number of defects after development is shown in Table 7.

[0725] [Table 7]

[0726] Resist composition Total number of defects after development Example 3-1 R-8 470 Example 3-2 R-15 480 Example 3-3 R-16 480 Embodiment 3-4 R-17 500 Embodiment 3-5 R-18 550 Embodiment 3-6 R-19 580 Embodiment 3-7 R-20 580 Embodiment 3-8 R-33 600 Comparative Example 3-1 CR-3 1680 Comparative Example 3-2 CR-4 1660

[0727] The chemically amplified positive resist compositions (R-1 to R-41) of the present invention all show good isolated spacing resolution, LER and pattern rectangularity, and show values ​​with suppressed development load. On the other hand, for the resist compositions of the comparative examples (CR-1 to CR-5), CR-1 to CR-4 have unsatisfactory designs of base polymers, and have unsatisfactory performances such as line and spacing resolution, LER, and pattern rectangularity. CR-5 has a high dissolution rate of the unexposed portion of the polymer, forming a dome shape and deteriorating resolution. Moreover, in the evaluation of residue defects, CR-3 and CR-4 also have unsatisfactory performances. With respect to the design of the present invention, it is believed that by using a resist composition having a specific acetal-type acid-labile group and a base polymer having a limited number of halogen atoms, a pattern showing good resolution, pattern shape and LER, and having suppressed effects on residue defects of an alkaline developer, can be achieved, especially even in high-dose areas.

[0728] The resist pattern forming method using the chemically amplified positive resist composition of the present invention is useful for semiconductor device manufacturing, particularly for optical lithography in processing of transmission type and reflection type blank photomasks.

Claims

1. A chemically amplified positive resist composition comprising (A) a base polymer, (B) a photoacid generator and (C) a quencher, (A) a base polymer comprising a polymer containing a phenolic hydroxyl group-containing unit represented by the following formula (A1), an aromatic ring-containing unit represented by any of the following formulas (A2) to (A4), and a phenolic hydroxyl group-containing unit protected by an acid-labile group represented by the following formula (A5), (A) All repeating units contained in the base polymer are repeating units having an aromatic ring, The number of halogen atoms contained in the repeating unit constituting the base polymer (A) is 3 or less, In the formula, a1 is an integer satisfying 0≤a1≤5+2(a3)-a2, a2 ​​is an integer from 1 to 3, and a3 is an integer from 0 to 2. R A , is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X 1 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond to a carbon atom of the main chain, A 1 , is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, a part of -CH2- of the saturated alkylene group may be substituted by -O-, R 1 , is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom, In the formula, b and c are each independently an integer of 0 to 4, d1 is an integer of 0 to 5, d2 is an integer of 0 to 2, R A , is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X 2 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond to a carbon atom of the main chain, A 2 , is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, a part of -CH2- of the saturated alkylene group may be substituted by -O-, R 2 and R 3 , each independently represents a hydroxyl group, 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 8 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 8 carbon atoms which may be substituted by a halogen atom, R 4 , is an acetyl group, 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 thiol group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group, and when d2 is 1 or 2, it may also be a hydroxyl group, In the formula, e1 is an integer satisfying 0≤e1≤5+2(e3)-e2, e2 is an integer from 1 to 3, and e3 is an integer from 0 to 2. R A , is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X 3 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond to a carbon atom of the main chain, A 3 , is a single bond or a saturated alkylene group having 1 to 10 carbon atoms, a part of -CH2- of the saturated alkylene group may be substituted by -O-, R 5 , is a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which may be substituted by a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which may be substituted by a halogen atom, or a saturated hydrocarbonoxy group having 1 to 6 carbon atoms which may be substituted by a halogen atom, R AL When e2 is 1, it is an acetal-type acid-labile group represented by the following formula (AL-1); when e2 is 2 or more, it is a hydrogen atom or an acetal-type acid-labile group represented by the following formula (AL-1); however, at least one of them is an acetal-type acid-labile group represented by the following formula (AL-1), Wherein, f1 is an integer from 0 to 2, f2 is an integer satisfying 0≤f2≤5+2(f1), R 6 , is an acetyl group, a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbon oxy group having 1 to 20 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbon oxyalkyl group having 2 to 20 carbon atoms, a saturated hydrocarbon thialkyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group, R L1 , is a hydrocarbon group having 1 to 30 carbon atoms, Dashed lines are atomic bonds.

2. The chemically amplified positive resist composition according to claim 1, wherein: The phenolic hydroxyl group-containing unit is a repeating unit represented by the following formula (A1-1): In the formula, R A and a2, the same as above.

3. The chemically amplified positive resist composition according to claim 1, wherein: The phenolic hydroxyl-containing unit protected by an acid-labile group is a repeating unit represented by the following formula (A5-1): In the formula, R A , R 6 , f1, f2 and R L1 , the same as above.

4. The chemically amplified positive resist composition according to claim 1, wherein: (B) The acid strength (pKa) of the acid generated by the photoacid generator is -3.0 or more.

5. The chemically amplified positive resist composition according to claim 1, wherein: The content ratio of the (B) photoacid generator to the (C) quencher ((B) / (C)) is less than 3 in terms of mass ratio.

6. The chemically amplified positive resist composition according to claim 1, wherein: (B) The photoacid generator is an onium salt compound containing an anion represented by the following formula (B-1) or (B-2), In the formula, m1 and m2 are each independently an integer of 0 to 2, when m1=0, m3 is an integer of 1 to 5, when m1=1, m3 is an integer of 1 to 7, when m1=2, m3 is an integer of 1 to 9, when m2=0, m4 is an integer of 0 to 5, when m2=1, m4 is an integer of 0 to 7, when m2=2, m4 is an integer of 0 to 9, L 1 , is a single bond, an ether bond, an ester bond, a sulfonate bond, an amide bond, a carbonate bond or a carbamate bond, R 11 , each independently an iodine atom, or a branched or cyclic hydrocarbon group having 3 to 20 carbon atoms which may contain a hetero atom, at least one R 11 Yes and L 1 The carbon atom to which the bond is bonded is bonded to the adjacent carbon atom. When m3 is 2 or more, multiple R 11 They may also be bonded to each other and form a ring together with these bonded carbon atoms. R 12 , each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when m4 is 2 or more, a plurality of R 12 They may also be bonded to each other and form a ring together with these bonded carbon atoms. W 1 , is the carbon atom C of the adjacent aromatic ring 1 and C 2 The carbon atoms forming the ring may be substituted with a heteroatom-containing group. W 2 , is the carbon atom C of the adjacent aromatic ring 3 and C 4 The carbon atoms forming the ring may be substituted with a heteroatom-containing group. wherein n1 and n2 are each independently an integer of 0 to 2, when n2=0, n3 is an integer of 1 to 4, when n2=1, n3 is an integer of 1 to 6, when n2=2, n3 is an integer of 1 to 8, when n2=0, n4 is an integer of 0 to 3, when n2=1, n4 is an integer of 0 to 5, when n2=2, n4 is an integer of 0 to 7, but when n2=0, n3+n4 is 1 to 4, when n2=1, n3+n4 is 1 to 6, when n2=2, n3+n4 is 1 to 8, when n1=0, n5 is an integer of 1 to 5, when n1=1, n5 is an integer of 1 to 7, when n1=2, n5 is an integer of 1 to 9, R 21 , each independently an iodine atom, or a branched or cyclic hydrocarbon group having 3 to 20 carbon atoms which may contain a hetero atom, at least one R 21 Yes and L 11 The carbon atom to which the carbon atom is bonded is bonded to the adjacent carbon atom, and when n5 is 2 or more, multiple R 21 They may also be bonded to each other and form a ring together with these bonded carbon atoms. R 22 , each independently represents a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and when n4 is 2 or more, a plurality of R 22 They may also be bonded to each other and form a ring together with these bonded carbon atoms. R F1 , each independently represents 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, L 11 and L 12 , is a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond or a carbamate bond, X L , is a single bond or an alkylene group having 1 to 40 carbon atoms which may contain a hetero atom.

7. The chemically amplified positive resist composition according to claim 6, wherein: (B) The photoacid generator is an onium salt compound having no fluorine atom in the anion.

8. The chemically amplified positive resist composition according to claim 1, further comprising (D) a fluorine-containing polymer, wherein the fluorine-containing polymer (D) contains 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 contain 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), Wherein, x is 1, 2 or 3, y is an integer satisfying 0≤y≤5+2z-x, z is 0 or 1, k is 1, 2 or 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 independently a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms, R 103 , R 106 , R 107 and R 108 , each independently a hydrogen atom, a hydrocarbon group having 1 to 15 carbon atoms, a fluorinated hydrocarbon group having 1 to 15 carbon atoms, or an acid-labile group, R 103 , R 106 , R 107 and R 108 When it is a hydrocarbon group or a fluorinated hydrocarbon group, the carbon-carbon bond may be separated by an ether bond or a carbonyl group. R 109 , is a straight-chain or branched hydrocarbon group having 1 to 5 carbon atoms, which may be separated by a hydrogen atom or a heteroatom-containing group between carbon-carbon bonds, R 110 , is a linear or branched hydrocarbon group having 1 to 5 carbon atoms, wherein a heteroatom-containing group may be present between carbon-carbon bonds, R 111 , is a saturated hydrocarbon group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted by a fluorine atom, and a portion of -CH2- in the saturated hydrocarbon group may be substituted by an ester bond or an ether bond, Z 1 , is a (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms, Z 2 , is a single bond, *-C(=O)-O- or *-C(=O)-NH-, 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, * are atomic bonds to carbon atoms of the backbone chain. 9 . The chemically amplified positive resist composition according to claim 1 , further comprising (E) an organic solvent.

10. The chemically amplified positive resist composition according to claim 1, wherein: The dissolution rate of the base polymer in the alkaline developer is 5 nm / min or less.

11. The chemically amplified positive resist composition according to claim 1, wherein: The dissolution rate of the unexposed portion of the resist film obtained from the chemically amplified positive resist composition in an alkaline developer is 10 nm / min or less.

12. The chemically amplified positive resist composition according to claim 1, which is used for electron beam lithography.

13. A method for forming a resist pattern, comprising the following steps: A resist film is formed on a substrate using the chemically amplified positive resist composition according to any one of claims 1 to 12, a pattern is irradiated on the resist film using extreme ultraviolet rays or electron beams, and the resist film irradiated with the pattern is developed using an alkaline developer.

14. The resist pattern forming method according to claim 13, wherein: The outermost surface of the substrate is made of a material containing at least one selected from the group consisting of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten and tin.

15. The resist pattern forming method according to claim 13, wherein: The substrate is a transmission type or reflection type blank mask.

16. A transmission or reflection type blank mask coated with the chemically amplified positive resist composition according to any one of claims 1 to 12.

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