Chemically amplified positive resist composition and method of forming resist pattern

Abstract

To provide a chemically amplified positive resist composition having good solvent solubility, excellent in lithography performance such as resolution, LER (line edge roughness) and pattern profile in photolithography using high-energy radiation, and also having high resistance to pattern collapse and excellent etching resistance even in fine pattern formation, and a pattern forming method using the chemically amplified resist composition.SOLUTION: A chemically amplified positive resist composition comprising (A) a base polymer comprising a polymer which increases its solubility in alkaline aqueous solution under the action of acid and comprises a recurring unit having an aromatic sulfonate anion of the following formula (A1) and a recurring unit of specific structure having a phenolic hydroxyl group on a side chain: SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In recent years, the increasing integration density of integrated circuits has led to a demand for finer pattern formation, and chemically amplified resist compositions using acid as a catalyst are used exclusively for processing patterns of 0.2 μm or less. High-energy radiation such as ultraviolet light, far ultraviolet light, and electron beam (EB) radiation are used as exposure sources for this purpose. EB lithography, which is particularly utilized as an ultrafine processing technology, has also become essential as a processing method for photomask blanks when producing photomasks for semiconductor manufacturing. Resist compositions used in this type of photolithography include positive-type resists, which form patterns by dissolving exposed areas, and negative-type resists, which form patterns by leaving exposed areas intact. The most convenient type is selected based on the desired resist pattern.

[0003] Typically, EB lithography is performed without a mask. In the case of positive-tone resists, the EB is sequentially irradiated onto areas other than the desired resist film. In the case of negative-tone resists, the EB is sequentially irradiated onto the desired resist film. This process requires sweeping the EB across the entire finely divided area of ​​the processing surface, which takes longer than one-shot exposure using a photomask. To maintain throughput, the resist film must be highly sensitive. Furthermore, the long lithography time can easily lead to differences between the initial and later lithography regions, making the stability of the exposed area over time in vacuum a key performance requirement. Furthermore, in the processing of photomask blanks, which is a particularly important application, the photomask substrate often contains surface materials, such as chromium oxide and other chromium compounds, that can affect the pattern shape of the chemically amplified resist film. Maintaining a rectangular resist pattern profile, regardless of the type of substrate, is also crucial to maintaining high resolution and post-etching shape.

[0004] Various improvements have been made to the control of the sensitivity and pattern profile of the resist film described above, such as by selecting and combining materials used in the resist composition and by adjusting process conditions. One of these improvements addresses the issue of acid diffusion, which has a significant impact on the resolution of chemically amplified resist films. In photomask processing, it is required that the shape of the resulting resist pattern does not change over time until post-exposure bake (PEB). A major cause of time-dependent changes is the diffusion of acid generated by exposure. This issue of acid diffusion has been extensively investigated, not only in photomask processing but also in general resist compositions, as it has a significant impact on sensitivity and resolution.

[0005] Patent Documents 1 and 2 describe examples in which acid diffusion is suppressed and roughness is reduced by increasing the bulk of the acid generated from an acid generator. However, these acid generators are still insufficient in suppressing acid diffusion, and therefore, there has been a demand for the development of an acid generator with even smaller diffusion.

[0006] Furthermore, Patent Documents 3 to 6 describe examples of controlling acid diffusion by bonding sulfonic acid generated upon exposure to a resin used in a resist composition. This method of suppressing acid diffusion by introducing a repeating unit that generates acid upon exposure into a base polymer is effective for obtaining patterns with small line edge roughness (LER). However, depending on the structure and introduction rate of such repeating units, there have been cases where problems have arisen with the solubility of base polymers containing repeating units that generate acid upon exposure in organic solvents.

[0007] Polymers containing a large amount of aromatic skeletons with acidic side chains, such as polyhydroxystyrene, have been used as materials for resist compositions for KrF lithography, but have not been used as materials for resist compositions for ArF lithography because they exhibit high absorption of light with wavelengths around 200 nm. However, they are important materials for resist compositions for EB lithography, which is a powerful technique for forming patterns smaller than the processing limit of ArF lithography, and for resist compositions for extreme ultraviolet (EUV) lithography, because they provide high etching resistance.

[0008] The base polymers used in positive-tone resist compositions for EB lithography and EUV lithography are typically made of materials that, upon exposure to high-energy radiation, use an acid generated from a photoacid generator as a catalyst to deprotect the acid-labile groups (acid-labile protecting groups) that mask the acidic functional groups on the phenol side chains of the base polymer, rendering the polymer soluble in alkaline developers. Tertiary alkyl groups, tert-butoxycarbonyl groups, acetal groups, and the like have typically been used as such acid-labile groups. While using protecting groups such as acetal groups, which require relatively low activation energy for deprotection, offers the advantage of producing highly sensitive resist films, insufficient suppression of the diffusion of the generated acid can lead to deprotection reactions in unexposed areas of the resist film, resulting in problems such as degradation of LER and reduced linewidth dimensional uniformity (CDU).

[0009]

[0003] With the recent progress in miniaturization of resist patterns, problems such as collapse of the resist pattern during development and poor resistance in the etching process have become an issue. Although the introduction of the repeating unit that generates acid upon exposure has suppressed the acid diffusion of the generated acid to some extent, there remains room for improvement in various lithography performances, collapse of the resist pattern, and poor etching resistance. In order to meet the future demands for miniaturization, it is extremely important to develop a polymeric acid generator that combines lithography performance with good resistance to collapse of the resist pattern and good etching resistance. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-053518 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-100604 [Patent Document 3] Patent No. 4425776 [Patent Document 4] Patent No. 5201363 [Patent Document 5] Patent No. 5231357 [Patent Document 6] International Publication No. 2008 / 081832 Summary of the Invention [Problem to be solved by the invention]

[0011] In recent years, there has been a demand for resist compositions that are excellent not only in line and space (LS), isoline (IL), and isospace (IS) patterns, but also in hole pattern shapes and exhibit excellent etching resistance after pattern formation.

[0012] The present invention has been made in view of the above circumstances, and has an object to provide a chemically amplified positive resist composition that exhibits good solvent solubility and excellent lithography performance such as resolution, LER, and pattern shape, particularly when used in photolithography using high-energy rays such as KrF excimer laser light, ArF excimer laser light, EB, and EUV, and that is resistant to pattern collapse and has excellent etching resistance even when forming fine patterns, and a pattern formation method that uses the chemically amplified resist composition. [Means for solving the problem]

[0013]

[0013] As a result of extensive investigations in order to achieve the above-mentioned object, the present inventors have found that by using a polymer that contains a repeating unit derived from an onium salt that comprises an aromatic sulfonate anion having a polymerizable group and a triarylsulfonium cation having an iodine atom on the aromatic ring, and a repeating unit that contains a phenolic hydroxy group, as a polymer-bonded acid generator, as a material for a chemically amplified positive resist composition, the resist composition has good solvent solubility particularly in EB lithography and EUV lithography, and excellent lithography performance such as resolution, LER, and pattern shape, as well as resistance to pattern collapse even in the formation of fine patterns and excellent etching resistance, and have completed the present invention.

[0014] That is, the present invention provides the following chemically amplified positive resist composition and method of forming a resist pattern. 1. A chemically amplified positive resist composition comprising a base polymer (A) containing a polymer whose solubility in an alkaline aqueous solution increases under the action of an acid, the polymer comprising a repeating unit composed of an aromatic sulfonate anion represented by the following formula (A1-1) and a sulfonium cation represented by the following formula (A1-2), and a repeating unit represented by the following formula (A2), and whose solubility in an alkaline aqueous solution increases under the action of an acid. [ka] (In the formula, n1 is 0 or 1. When n1 is 0, n2 is 0, 1, 2, 3, or 4, and when n1 is 1, n2 is 0, 1, 2, 3, 4, 5, or 6. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 1 is a halogen atom, a nitro group, a cyano group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. When n2 is 2 or more, each R 1 may be the same or different, and multiple R 1may be bonded to each other to form a ring together with the carbon atoms to which they are attached. X 1 is a single bond, an ether bond, an ester bond, or an amide bond. [ka] (Wherein, m1 is 0 or 1. m2 is 0 or 1. m3 is 0 or 1. m4 is 0, 1, 2, 3 or 4. m5 is 0, 1, 2, 3 or 4. m6 is 0, 1, 2, 3, 4, 5 or 6. m7 is 0, 1, 2, 3, 4, 5 or 6. m8 is 0, 1 or 2. m9 is 0, 1 or 2. m10 is 0, 1 or 2. m11 is 0 or 1. m12 is 0, 1, 2, 3 or 4. m13 is 0, 1 or 2. m14 is 0, 1 or 2. However, when m1 is 0, 0≦m6+m9≦4, and when m1 is 1, 0≦m6+m9≦6. When m2 is 0, 0≦m7+m10≦4, and when m2 is 1, 0≦m7+m10≦6. When m3 is 0, 1≦m4+m5+m8+m14≦4, and when m3 is 1, 1≦m4+m5+m8+m14≦6. When m11 is 0, 0≦m12+m13≦4, and when m11 is 1, 0≦m12+m13≦6. Also, m4+m12≧1. R F1 ~R F3 are each independently a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms. When m5 is 2 or more, each R F1 may be the same or different, and when m6 is 2 or more, each R F2 may be the same or different, and when m7 is equal to or greater than 1, each R F3 may be the same or different from each other. R 2 ~R 5is a halogen atom other than an iodine atom or a fluorine atom, a nitro group, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. When m8 is 2, two R 2 may be the same or different, and two R 2 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. When m9 is 2, two R 3 may be the same or different, and two R 3 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. When m10 is 2, two R 4 may be the same or different, and two R 4 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. When m13 is 2, two R 5 may be the same or different, and two R 5 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. In addition, S in the sulfonium cation + The aromatic rings directly bonded to S + may form a ring together with L A and L B are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate ester bond, a sulfonamide bond, a carbonate bond or a carbamate bond. X L is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. [ka] (In the formula, a1 is 0 or 1. a2 is 0, 1, or 2. a3 is an integer that satisfies 0≦a3≦5+2(a2)−a4. a4 is 1, 2, or 3. R Ais a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 11 is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. A 1 represents a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and —CH2— of the saturated hydrocarbylene group may be substituted with —O—. 2. The chemically amplified positive resist composition of 1, wherein the sulfonium cation represented by the formula (A2) is represented by the following formula (A1-2-1): [ka] (In the formula, m4~m10, m12~m14, R F1 ~R F3 , R 2 ~R 5 , L A , L B and X L is the same as above.) 3. The chemically amplified positive resist composition of 2, wherein the sulfonium cation represented by the formula (A1-2-1) is represented by the following formula (A1-2-2): [ka] (In the formula, m4~m10, R F1 ~R F3 and R 2 ~R 5 is the same as above.) 4. The chemically amplified positive resist composition of any one of 1 to 3, wherein the repeating unit represented by formula (B1) is represented by the following formula (A2-1): [ka] (In the formula, R A and a4 are the same as above.) 5. The chemically amplified positive resist composition of any one of 1 to 4, wherein the polymer further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (A3-1) and a repeating unit represented by the following formula (A3-2): [ka] (In the formula, b1 is 0 or 1. b2 is 0, 1, or 2. b3 is an integer that satisfies 0≦b3≦5+2(b2)−b4. b4 is 1, 2, or 3. b5 is 0 or 1. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 12 is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and some of the -CH2- in the saturated hydrocarbylene group may be substituted with -O-. When b4 is 1, X is an acid labile group. When b4 is 2 or 3, X is each independently a hydrogen atom or an acid labile group, provided that at least one X is an acid labile group. c1 is 0, 1 or 2. c2 is 0, 1 or 2. c3 is 0, 1, 2, 3, 4 or 5. c4 is 0, 1 or 2. R 13 and R 14 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, and R 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 15 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms. R 16are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. A 3 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OA 31 -It is. A 31 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group, or a naphthylene group, and the aliphatic hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. * represents a bond to a carbon atom in the main chain. 6. The chemically amplified positive resist composition of any one of 1 to 5, wherein the polymer further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (B3), a repeating unit represented by the following formula (B4), and a repeating unit represented by the following formula (B5): [ka] (In the formula, d is 0, 1, 2, 3, 4, 5, or 6. e is 0, 1, 2, 3, or 4. f1 is 0 or 1. f2 is 0, 1, or 2. f3 is 0, 1, 2, 3, 4, or 5. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 17 and R 18 are each independently a hydroxy group, a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 19 represents a halogen atom, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms or a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, and when f2 is 1 or 2 it may be a hydroxy group. A4 represents a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and —CH2— of the saturated hydrocarbylene group may be substituted with —O—. 7. The chemically amplified positive resist composition of any one of 1 to 6, wherein the content of repeating units having an aromatic ring skeleton in all repeating units of the polymer contained in the (A) base polymer is 60 mol % or more. 8. The chemically amplified positive resist composition according to any one of 1 to 7, further comprising (B) a quencher. 9. The chemically amplified positive resist composition according to any one of 1 to 8, further comprising (C) an organic solvent. 10.Furthermore, (D) 10. The chemically amplified positive resist composition according to any one of 1 to 9, comprising a fluorine atom-containing polymer containing at least one repeating unit 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): [ka] (wherein h is 1, 2 or 3. R B are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 201 , R 202 , R 204 and R 205 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R 203 , R 206 , R 207 and R 208 are each independently a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group, and R 203 , R 206 , R 207 and R 208 When is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bonds. Z 1is a (h+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (h+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. 11. The chemically amplified positive resist composition of 10, wherein the fluorine atom-containing polymer further comprises at least one repeating unit 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): [ka] (In the formula, x is 1, 2, or 3. y is an integer satisfying 0≦y≦5+2z−x. z is 0 or 1. R C are each independently a hydrogen atom or a methyl group. R 209 is a hydrogen atom or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a group containing a hetero atom interposed between its carbon-carbon bond. R 210 is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a group containing a hetero atom interposed between its carbon-carbon bond. R 211 is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom has been substituted with a fluorine atom, and some of the -CH2- groups in the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. 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 -It is. Z 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 is a single bond, an ester bond, an ether bond or a sulfonamide bond. * indicates a bond to a carbon atom in the main chain.) 12. The chemically amplified positive resist composition according to any one of 1 to 11, further comprising (E) an acid generator. 13. A method for forming a resist pattern, comprising the steps of: forming a resist film on a substrate using the chemically amplified positive resist composition according to any one of claims 1 to 12; irradiating the resist film with a pattern using high-energy rays; and developing the resist film irradiated with the pattern using an alkaline developer. 14. The method for forming a resist pattern according to 13, wherein the high-energy radiation is KrF excimer laser light, ArF excimer laser light, extreme ultraviolet light, or an electron beam. 15. The method for forming a resist pattern according to 13 or 14, wherein the outermost surface of the substrate is made of a material containing at least one element selected from the group consisting of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten, and tin. 16. The method for forming a resist pattern according to any one of 13 to 15, wherein the substrate is a transmission or reflection mask blank. 17. A transmission or reflection mask blank coated with any one of the chemically amplified positive resist compositions set forth in 1 to 12. [Effects of the Invention]

[0015] The chemically amplified positive resist composition of the present invention exhibits extremely high resolution and can produce patterns with small LER in microfabrication techniques, particularly in EB lithography and EUV lithography. Furthermore, it also exhibits excellent etching resistance after resist pattern formation, making it suitable as a chemically amplified positive resist material. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a nuclear magnetic resonance spectrum ( 1 H-NMR / DMSO-d 6 ) of the onium-type monomer A1-1 synthesized in Synthesis Example 1-1. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described in detail below. In the following description, some structures represented by chemical formulas may have asymmetric carbon atoms, and enantiomers or diastereomers may exist. In such cases, a single formula will be used to represent all isomers. These isomers may be used singly or as a mixture of two or more.

[0018] [Chemically amplified positive resist composition] [(A) Base polymer] The resist composition of the present invention contains, as the component (A), a base polymer that contains a polymer that decomposes under the action of an acid, and whose solubility in an alkaline developer increases.

[0019] The polymer contains a repeating unit (hereinafter also referred to as repeating unit A1) derived from an onium salt composed of an aromatic sulfonate anion having a polymerizable group and a triarylsulfonium cation having an iodine atom on the aromatic ring.

[0020] The anion of the repeating unit A1 is represented by the following formula (A1-1). [ka]

[0021] In formula (A1-1), n1 is 0 or 1. When n1 is 0, it is a benzene ring, and when n1 is 1, it is a naphthalene ring; however, from the viewpoint of solvent solubility, n1 is preferably a benzene ring of 0. When n1 is 0, n2 is 0, 1, 2, 3, or 4, and when n1 is 1, it is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material procurement, n2 is preferably 0, 1, 2, 3, or 4, and more preferably 0, 1, or 2.

[0022] In formula (A1-1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0023] In formula (A1-1), R 1is a halogen atom, a nitro group, a cyano group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and more preferably a fluorine atom or an iodine atom. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group and hydrocarbylthio group may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl groups; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, and 4-methyl Examples of such groups include saturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl; unsaturated cyclic hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclohexenyl; aryl groups having 2 to 20 carbon atoms, such as phenyl and naphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl; and groups obtained by combining these groups. Of these, aryl groups are preferred.In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, resulting in the hydrocarbyl group containing a hydroxy group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. In addition, when n2 is 2 or more, each R. 1 may be the same as or different from each other.

[0024] Also, when n2 is equal to or greater than 1, multiple R 1 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH- groups in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the ring containing a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0025] In formula (A1-1), X 1 is a single bond, an ether bond, an ester bond, or an amide bond. Of these, a single bond or an ester bond is preferred, and a single bond is more preferred.

[0026] Specific examples of the aromatic sulfonate anion represented by formula (A1-1) include, but are not limited to, the following:A is the same as above. [ka]

[0027] [ka]

[0028] The sulfonium cation of the repeating unit A1 is represented by the following formula (A1-2). [ka]

[0029] In formula (A1-2), m1 is 0 or 1. When m1 is 0, it is a benzene ring, and when m1 is 1, it is a naphthalene ring, although from the viewpoint of solvent solubility, it is preferably a benzene ring with m1 being 0. m2 is 0 or 1. When m2 is 0, it is a benzene ring, and when m2 is 1, it is a naphthalene ring, although from the viewpoint of solvent solubility, it is preferably a benzene ring with m1 being 0. m3 is 0 or 1. When m3 is 0, it is a benzene ring, and when m3 is 1, it is a naphthalene ring, although from the viewpoint of solvent solubility, it is preferably a benzene ring with m3 being 0.

[0030] In formula (A1-2), m4 is 0, 1, 2, 3, or 4. As the number of iodine atoms in the cation structure increases, the solvent solubility decreases, which may lead to precipitation in the resist composition. Therefore, m4 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0031] In formula (A1-2), m5 is 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, m5 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. m6 is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material procurement, m6 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2. m7 is 0, 1, 2, 3, 4, 5, or 6. From the viewpoint of raw material procurement, m7 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0032] In formula (A1-2), m8 is 0, 1, or 2. From the viewpoint of raw material procurement, m8 is preferably 0 or 1. m9 is 0, 1, or 2. From the viewpoint of raw material procurement, m9 is preferably 0 or 1. m10 is 0, 1, or 2. From the viewpoint of raw material procurement, m10 is preferably 0 or 1.

[0033] In formula (A1-2), m11 is 0 or 1. When m11 is 0, it is a benzene ring, and when m11 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that m11 is 0 and is a benzene ring.

[0034] In formula (A1-2), m12 is 0, 1, 2, 3, or 4. As the number of iodine atoms in the cation structure increases, solvent solubility decreases, raising the risk of precipitation in the resist composition. Therefore, m12 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0035] In formula (A1-2), m13 is 0, 1, or 2. From the viewpoint of raw material procurement, m13 is preferably 0 or 1. m14 is 0, 1, or 2. From the viewpoint of synthesis, m14 is preferably 0 or 1.

[0036] However, when m1 is 0, 0≦m6+m9≦4, and when m1 is 1, 0≦m6+m9≦6. When m2 is 0, 0≦m7+m10≦4, and when m2 is 1, 0≦m7+m10≦6. When m3 is 0, 1≦m4+m5+m8+m14≦4, and when m3 is 1, 1≦m4+m5+m8+m14≦6. When m11 is 0, 0≦m12+m13≦4, and when m11 is 1, 0≦m12+m13≦6. Also, m4+m12≧1.

[0037] In formula (A1-2), R F1 ~R F3 are each independently a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms. Among these, a trifluoromethyl group, a trifluoromethoxy group, or a trifluorothiomethoxy group is preferred. When m5 is 2 or more, each R F1 may be the same or different, and when m6 is 2 or more, each R F2 may be the same or different, and when m7 is 2 or more, each R F3 may be the same or different from each other.

[0038] In formula (A1-2), R 2 ~R 5 are each independently a halogen atom other than iodine atom or fluorine atom, a nitro group, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbyloxy group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 1In addition, some or all of the hydrogen atoms in the hydrocarbyl moiety of the hydrocarbyl group, hydrocarbyloxy group, and hydrocarbylthio group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- in the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, so that the hydrocarbyl group may contain a hydroxy group, cyano group, fluorine atom, chlorine atom, bromine atom, iodine atom, carbonyl group, ether bond, ester bond, sulfonate ester bond, carbonate bond, lactone ring, sultone ring, carboxylic anhydride (-C(=O)-OC(=O)-), haloalkyl group, etc.

[0039] Also, when m8 is 2, two R 2 may be the same or different, and two R 2 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. When m9 is 2, two R 3 may be the same or different, and two R 3 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. When m10 is 2, two R 4 may be the same or different, and two R 4 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. When m13 is 2, two R 5 may be the same or different, and two R 5may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH- groups in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in the ring containing a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0040] In addition, S in the sulfonium cation represented by formula (A1-2) + The aromatic rings directly bonded to S + In this case, specific examples of the ring structure include those represented by the following formulas: [ka] (In the formula, the dashed lines represent bonds.)

[0041] In formula (A1-2), L A and L B are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate ester bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. A is preferably a single bond, an ether bond, an ester bond or a sulfonate ester bond, and more preferably an ester bond or a sulfonate ester bond. B is preferably a single bond, an ether bond or an ester bond, and more preferably a single bond.

[0042] In formula (A1-2), X Lis a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include an alkanediyl group and a divalent saturated cyclic hydrocarbon group. Examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom.

[0043] X L As the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a hetero atom, represented by the following formula, the following is preferred: In the following formula, * represents L A and L B Represents a bond with [ka]

[0044] [ka]

[0045] [ka]

[0046] Of these, X L -0~X L -3, X L -29~X L -34 and X L -47~X L -49 is preferred, X L -0~X L -2, X L -29 and X L -47 is more preferable.

[0047] The sulfonium cation represented by formula (A1-2) is preferably one represented by the following formula (A1-2-1). [ka] (In the formula, m4~m10, m12~m14, R F1 ~RF3 , R 2 ~R 5 , L A , L B and X L is the same as above.)

[0048] The sulfonium cation represented by formula (A1-2-1) is preferably one represented by the following formula (A1-2-2). [ka] (In the formula, m4~m10, R F1 ~R F3 and R 2 ~R 5 is the same as above.)

[0049] Specific examples of the sulfonium cation represented by formula (A1-2) include, but are not limited to, the following: In the following formula, Me is a methyl group. [ka]

[0050] [ka]

[0051] [ka]

[0052] [ka]

[0053] [ka]

[0054] [ka]

[0055]

change

[0056]

change

[0057]

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[0058]

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[0059]

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[0060]

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[0061]

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[0062]

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[0063]

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[0064]

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[0065]

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[0066]

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[0067]

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[0068]

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[0069]

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[0070]

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[0071]

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[0072]

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[0073]

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[0074]

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[0075]

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[0076] [ka]

[0077] Specific examples of the repeating unit A1 include any combination of the above-mentioned anions and cations.

[0078] Methods for synthesizing a monomer derived from the repeating unit A1 include those described in JP 2010-155824 A, Japanese Patent No. 7067271 A, etc. However, the above-mentioned production methods are merely examples, and the production method for a monomer derived from the repeating unit A1 is not limited to these.

[0079] A structural feature of the repeating unit A1 is that the polymerizable group is derived from an onium salt consisting of an aromatic sulfonate anion directly bonded to an aromatic ring and a triarylsulfonium cation containing an iodine atom. The aromatic sulfonate anion, in which the polymerizable group is directly bonded to the aromatic ring, generates acid upon exposure. However, the aromatic sulfonic acid is directly bonded to the polymer backbone, allowing for highly controlled acid diffusion. Furthermore, the aromatic rings interact with other aromatic ring-containing copolymer units (π-π stacking interactions), resulting in a regular, dense arrangement, which prevents pattern collapse. Meanwhile, the aromatic sulfonate anion, in which the polymerizable group is directly bonded to the aromatic ring, is not very soluble in organic solvents. Furthermore, the presence of an iodine atom in the triarylsulfonium cation further reduces solubility. However, organic solvent solubility can be maintained by separately introducing multiple fluorine atoms into the aromatic ring of the cation. Furthermore, the electron-withdrawing properties of the iodine and fluorine atoms in the cations lower the energy level of the lowest unoccupied molecular orbital (LUMO) in frontier orbital theory, making them more susceptible to the secondary electrons generated. This accelerates the decomposition of the cations, resulting in the effective generation of acid, resulting in high sensitivity. In the exposed areas, efficient decomposition of the cations generates sufficient acid, leading to favorable deprotection of the base polymer's protecting groups. Furthermore, the aromatic sulfonic acid bonded to the base polymer's main chain is highly soluble in alkaline developer, resulting in a high dissolution rate in alkaline developer. Meanwhile, in the unexposed areas, the iodine atoms in the triarylsulfonium cations exhibit dissolution-inhibiting properties in alkaline developer, reducing film loss in the unexposed pattern. This improves dissolution contrast. These synergistic effects enable the chemically amplified positive resist composition of the present invention to exhibit high sensitivity and low acid diffusibility, resulting in excellent resolution and LER, and enabling the formation of patterns that are resistant to pattern collapse, making it suitable for fine pattern formation.

[0080] The repeating unit A1 can be suitably used as a polymer-bound photoacid generator.

[0081] The polymer further contains a repeating unit A2 having a phenolic hydroxy group represented by the following formula (A2). [ka]

[0082] In formula (A2), a1 is 0 or 1. a2 is 0, 1, or 2; when 0, it represents a benzene skeleton, when 1, it represents a naphthalene skeleton, and when 2, it represents an anthracene skeleton. a3 is an integer that satisfies 0≦a3≦5+2(a2)−a4. a4 is 1, 2, or 3. When a2 is 0, a3 is preferably 0, 1, 2, or 3, and a4 is preferably 1, 2, or 3. When a2 is 1 or 2, a3 is preferably 0, 1, 2, 3, or 4, and a4 is preferably 1, 2, or 3.

[0083] In formula (A2), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0084] In formula (A2), R 11 is a halogen atom, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group and the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, hexyl, and structural isomers thereof; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining these. When the number of carbon atoms is equal to or less than the upper limit, the solubility in alkaline developers is good. When a3 is 2 or more, each R 11 may be the same as or different from each other.

[0085] In formula (A2), A 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a portion of the -CH2- in the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl 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, and hexane-1,6-diyl, and structural isomers thereof; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms, such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining these. When the saturated hydrocarbylene group contains an ether bond, when a1 in formula (A2) is 1, the ether bond may be located anywhere except between the carbon atom at the α-position and the carbon atom at the β-position relative to the ester oxygen atom. When a1 is 0, the atom bonding to the main chain is an etheric oxygen atom, and the second ether bond may be inserted at any position except between the carbon atom at the α-position and the carbon atom at the β-position relative to the etheric oxygen atom. Note that if the number of carbon atoms in the saturated hydrocarbylene group is 10 or less, sufficient solubility in an alkaline developer can be obtained, which is preferable.

[0086] a1 is 0 and A 1 is a single bond, i.e., the aromatic ring is directly attached to the polymer backbone (i.e., the linker (-C(=O)-OA 1 When the repeating unit A2 does not have -), preferred examples of the repeating unit A2 include units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, etc. In particular, the repeating unit represented by the following formula (A2-1) is preferred. [ka] (In the formula, R A and a4 are the same as above.)

[0087] a1 is 0 and A 1 is a single bond (i.e., the linker (-C(=O)-OA 1 In the case where R does not have -), preferred examples of the repeating unit A2 include, but are not limited to, those shown below. A is the same as above. [ka]

[0088] [ka]

[0089] [ka]

[0090] [ka]

[0091] [ka]

[0092] a1 is 1 (i.e., -C(=O)-OA as a linker) 1 In the case where R A is the same as above. [ka]

[0093] [ka]

[0094] [ka]

[0095] [ka]

[0096] [ka]

[0097] [ka]

[0098] The content of repeating unit A2 is preferably 30 to 90 mol %, more preferably 40 to 85 mol %, of all repeating units in the polymer. However, when at least one of repeating units represented by formula (A4) and repeating units represented by formula (A5), which will be described later and which impart high etching resistance to the polymer, is contained and this unit has a phenolic hydroxy group as a substituent, the proportion of this unit is also preferably within the above range. Repeating unit A2 may be used alone or in combination of two or more types.

[0099] In order to provide the polymer as a positive resist composition with the property that exposed areas are soluble in an alkaline developer, it is preferable that the polymer contains a repeating unit having an acidic functional group protected by an acid labile group, i.e., a repeating unit that is protected by an acid labile group and becomes alkali-soluble through the action of an acid (hereinafter also referred to as repeating unit A3).

[0100] The most preferred repeating unit A3 is one represented by the following formula (A3-1) (hereinafter also referred to as repeating unit A3-1). [ka]

[0101] In formula (A3-1), b1 is 0 or 1. b2 is 0, 1, or 2; when 0, it represents a benzene skeleton; when 1, it represents a naphthalene skeleton; and when 2, it represents an anthracene skeleton. b3 is an integer that satisfies 0≦b3≦5+2(b2)−b4. b4 is 1, 2, or 3. b5 is 0 or 1. When b2 is 0, b3 is preferably 0, 1, 2, or 3, and b4 is 1, 2, or 3; when b2 is 1 or 2, b3 is preferably 0, 1, 2, 3, or 4, and b4 is 1, 2, or 3.

[0102] In formula (A3-1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0103] In formula (A3-1), R 12 is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group and the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, hexyl, and structural isomers thereof; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining these. When the number of carbon atoms is equal to or less than the upper limit, the solubility in an alkaline developer is good. When b3 is 2 or more, each R 12 may be the same as or different from each other.

[0104] In formula (A3-1), A 2is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and some of the -CH2- in the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl 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, and hexane-1,6-diyl, and structural isomers thereof; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms, such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining these. When the saturated hydrocarbylene group contains an ether bond, when b1 in formula (A3-1) is 1, the ether bond may be located anywhere except between the carbon atom at the α-position and the carbon atom at the β-position relative to the ester oxygen atom. When b1 is 0, the atom bonding to the main chain is an etheric oxygen atom, and the second ether bond may be inserted at any position except between the carbon atom at the α-position and the carbon atom at the β-position relative to the etheric oxygen atom. Note that if the number of carbon atoms in the saturated hydrocarbylene group is 10 or less, sufficient solubility in an alkaline developer can be obtained, which is preferable.

[0105] In formula (A3-1), when b4 is 1, X is an acid labile group. When b4 is 2 or 3, X is each independently a hydrogen atom or an acid labile group, with at least one being an acid labile group. That is, in the repeating unit A3-1, at least one phenolic hydroxy group bonded to an aromatic ring is protected with an acid labile group, or a carboxy group bonded to an aromatic ring is protected with an acid labile group. The acid labile group is not particularly limited, and any of those that have been used in many known chemically amplified positive resist compositions and that are cleaved by an acid to give an acidic group can be used.

[0106] The acid labile group may be, for example, a tertiary saturated hydrocarbyl group. The tertiary saturated hydrocarbyl group preferably has 4 to 18 carbon atoms so that the resulting monomer for polymerization can be obtained by distillation.

[0107] The saturated hydrocarbyl group bonded to the tertiary carbon atom of the tertiary saturated hydrocarbyl group preferably has 1 to 15 carbon atoms. The saturated hydrocarbyl group having 1 to 15 carbon atoms may be linear, branched, or cyclic, and may contain an ether bond or an oxygen atom-containing functional group such as a carbonyl group between its carbon-carbon bond. Furthermore, the saturated hydrocarbyl groups bonded to the tertiary carbon atom may be bonded to each other to form a ring together with the tertiary carbon atom to which they are attached.

[0108] Examples of the saturated hydrocarbyl group bonded to the tertiary carbon atom include a methyl group, an ethyl group, a propyl group, an adamantyl group, a norbornyl group, a tetrahydrofuran-2-yl group, a 7-oxanorbornan-2-yl group, a cyclopentyl group, a 2-tetrahydrofuryl group, a tricyclo[5.2.1.0 2,6 ]decyl group, 8-ethyl-8-tricyclo[5.2.1.0 2,6 ]decyl group, 3-methyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodecyl group, tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodecyl group, 3-oxo-1-cyclohexyl group, and the like.

[0109] Examples of the tertiary saturated hydrocarbyl group include a tert-butyl group, a tert-pentyl group, a 1-ethyl-1-methylpropyl group, a 1,1-diethylpropyl group, a 1,1,2-trimethylpropyl group, a 1-adamantyl-1-methylethyl group, a 1-methyl-1-(2-norbornyl)ethyl group, a 1-methyl-1-(tetrahydrofuran-2-yl)ethyl group, a 1-methyl-1-(7-oxanorbornan-2-yl)ethyl group, a 1-methylcyclopentyl group, a 1-ethylcyclopentyl group, 1-propylcyclopentyl group, 1-cyclopentylcyclopentyl group, 1-cyclohexylcyclopentyl group, 1-(2-tetrahydrofuryl)cyclopentyl group, 1-(7-oxanorbornan-2-yl)cyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, 1-cyclopentylcyclohexyl group, 1-cyclohexylcyclohexyl group, 2-methyl-2-norbornyl group, 2-ethyl-2-norbornyl group, 8-methyl-8-tricyclo[5.2.1.0] 2,6 ]decyl group, 8-ethyl-8-tricyclo[5.2.1.0 2,6 ]decyl group, 3-methyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodecyl group, 3-ethyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodecyl group, 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 1-methyl-3-oxo-1-cyclohexyl group, 1-methyl-1-(tetrahydrofuran-2-yl)ethyl group, 5-hydroxy-2-methyl-2-adamantyl group, and 5-hydroxy-2-ethyl-2-adamantyl group, but are not limited to these.

[0110] Further, examples of the acid labile group include groups represented by the following formula (A3-1-1). The group represented by formula (A3-1-1) is often used as an acid labile group and is a useful option as an acid labile group that stably gives a pattern in which the interface between the pattern and the substrate is relatively rectangular. When X is a group represented by formula (A3-1-1), an acetal structure is formed. [ka] (In the formula, the dashed lines represent bonds.)

[0111] In formula (A3-1-1), R L1 is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. The saturated hydrocarbyl group may be linear, branched or cyclic.

[0112] R L1 is appropriately selected depending on the design of the sensitivity of the decomposable group to acid. For example, if the design is to ensure relatively high stability while decomposing with strong acid, a group in which the carbon atom bonded to the hydrogen atom or acetal carbon is a tertiary carbon atom is preferred. R bonded to the acetal carbon by a tertiary carbon atom L1 Examples of R include, but are not limited to, a tert-butyl group, a tert-pentyl group, and a 1-adamantyl group. If the design is to achieve high sensitivity to pH changes by using relatively high reactivity, a straight-chain alkyl group is preferred. Depending on the combination with the acid generator and quencher to be compounded in the resist composition, R L2 When a relatively large alkyl group is selected at the end of the polymer, and the polymer is designed to have a large change in solubility due to decomposition, R L1 As for R, the carbon atom bonded to the acetal carbon is preferably a secondary carbon atom. L1 Examples of include, but are not limited to, an isopropyl group, a sec-butyl group, a cyclopentyl group, a cyclohexyl group, and the like.

[0113] In formula (A3-1-1), R L2is a hydrocarbyl group having 1 to 30 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A portion of the -CH2- in the hydrocarbyl group may be substituted with a heteroatom such as an oxygen atom or a sulfur atom, and as a result, the hydrocarbyl group may contain an ether bond, a sulfide bond, or the like. Specific examples of the hydrocarbyl group include saturated hydrocarbyl groups having 1 to 30 carbon atoms and aryl groups having 6 to 30 carbon atoms. In particular, in order to obtain higher resolution in the formation of fine patterns, R L2 is preferably a hydrocarbyl group having 1 to 6 carbon atoms. L2 When is a hydrocarbyl group having 1 to 6 carbon atoms, the alcohol generated after the deprotection reaction with an acid proceeds is water-soluble, and therefore dissolves in an alkaline developer when a positive pattern is formed using the developer, thereby making it possible to suppress residual defects in exposed areas.

[0114] Preferred examples of the group represented by formula (A3-1-1) include, but are not limited to, the following: L1 is the same as above, and the dashed line represents a bond. [ka]

[0115] [ka]

[0116] The acid labile group may also be a phenolic hydroxy group in which the hydrogen atom is substituted with -CHCOO- (a tertiary saturated hydrocarbyl group), which may be the same as the tertiary saturated hydrocarbyl group used to protect the phenolic hydroxy group described above.

[0117] Further examples of the repeating unit A3 include a repeating unit represented by the following formula (A3-2) (hereinafter also referred to as repeating unit A3-2): The repeating unit A3-2 increases the dissolution rate of the exposed area, making it a useful option as an acid labile group-containing unit that provides good performance against line width fluctuations during development loading. [ka]

[0118] In formula (A3-2), c1 is 0, 1 or 2. c2 is 0, 1 or 2. c3 is 0, 1, 2, 3, 4 or 5. c4 is 0, 1 or 2.

[0119] In formula (A3-2), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0120] In formula (A3-2), R 13 and R 14 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, and R 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached.

[0121] In formula (A3-2), R 15 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms.

[0122] In formula (A3-2), R 16 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom.

[0123] In formula (A3-2), A 3 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OA 31 -It is. A 31represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group, or a naphthylene group, and the aliphatic hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. * represents a bond to a carbon atom in the main chain.

[0124] Preferred examples of the repeating unit A3-2 include, but are not limited to, the following: A is the same as above. [ka]

[0125] [ka]

[0126] The content of the repeating unit A3 is preferably 5 to 95 mol %, more preferably 20 to 80 mol %, of all repeating units constituting the polymer. The repeating unit A3 may be used alone or in combination of two or more types.

[0127] The polymer may contain at least one selected from a repeating unit represented by the following formula (A4) (hereinafter also referred to as repeating unit A4), a repeating unit represented by the following formula (A5) (hereinafter also referred to as repeating unit A5), and a repeating unit represented by the following formula (A6) (hereinafter also referred to as repeating unit A6). [ka]

[0128] In the formulae (A4) and (A5), d is 0, 1, 2, 3, 4, 5, or 6. e is 0, 1, 2, 3, or 4.

[0129] In formulas (A4) and (A5), R 17 and R 18are each independently a hydroxy group, a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When d is 2 or more, each R 17 may be the same or different. When e is 2 or more, each R 18 may be the same as or different from each other.

[0130] In formula (A6), f1 is 0 or 1. f2 is 0, 1, or 2, and when 0, represents a benzene skeleton, when 1, represents a naphthalene skeleton, and when 2, represents an anthracene skeleton. f3 is 0, 1, 2, 3, 4, or 5. When f2 is 0, f3 is preferably 0, 1, 2, or 3, and when f2 is 1 or 2, f3 is preferably 0, 1, 2, 3, or 4.

[0131] In formula (A6), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0132] In formula (A6), R 19 is a halogen atom, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, or a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, and when f2 is 1 or 2, it may be a hydroxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, saturated hydrocarbyloxyhydrocarbyl group, and saturated hydrocarbylthiohydrocarbyl group may be linear, branched, or cyclic. When f3 is 2 or more, each R 19 may be the same as or different from each other.

[0133] In formula (A6), A 4 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a portion of -CH2- in the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic. Specific examples thereof include A in formula (A2): 1 Examples of the examples are similar to those given in the explanation of 1.

[0134] When at least one of the repeating units A4 to A6 is used as a structural unit of the polymer, the addition of a ring structure to the main chain provides the effect of improving etching resistance and EB irradiation resistance during pattern inspection in addition to the etching resistance of the aromatic ring.

[0135] To obtain the effect of improving etching resistance, the content of repeating units A4 to A6 is preferably 5 mol % or more of all repeating units constituting the polymer. Furthermore, the content of repeating units A4 to A6 is preferably 25 mol % or less, more preferably 20 mol % or less, of all repeating units constituting the polymer. When no functional group is present or when the functional group is other than a hydroxy group, it is preferable that the amount introduced is 25 mol % or less, since this does not cause development defects. Repeating units A4 to A6 may be used singly or in combination of two or more.

[0136] The content of repeating units having an aromatic ring skeleton in all repeating units of the polymer is preferably 65 mol % or more, more preferably 75 mol % or more, and even more preferably 85 mol % or more.

[0137] The polymer may contain commonly used (meth)acrylate units protected with an acid labile group, or (meth)acrylate units having an adhesive group such as a lactone structure or a hydroxy group other than a phenolic hydroxy group. These repeating units allow for fine adjustment of the properties of the resist film, but they do not necessarily have to be included.

[0138] Examples of the (meth)acrylic acid ester unit having the adhesive group include a repeating unit represented by the following formula (A7) (hereinafter also referred to as repeating unit A7), a repeating unit represented by the following formula (A8) (hereinafter also referred to as repeating unit A8), and a repeating unit represented by the following formula (A9) (hereinafter also referred to as repeating unit A9). These units do not exhibit acidity and can be used auxiliary as units that impart adhesion to substrates or units that adjust solubility. [ka]

[0139] In formulas (A7) to (A9), R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 21 is —O— or a methylene group. 22 is a hydrogen atom or a hydroxy group. 23 is a saturated hydrocarbyl group having 1 to 4 carbon atoms. g is 0, 1, 2 or 3.

[0140] When repeating units A7 to A9 are contained, the content thereof is preferably 0 to 20 mol %, more preferably 0 to 10 mol %, of all repeating units of the polymer. Repeating units B14 to B16 may be used alone or in combination of two or more.

[0141] The polymer can be synthesized by copolymerizing each monomer, optionally protected with a protecting group, using a known method, followed by a deprotection reaction as needed. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, see JP 2004-115630 A.

[0142] The polymer preferably has a weight-average molecular weight (Mw) of 1,000 to 50,000, more preferably 2,000 to 20,000. When Mw is 1,000 or more, there is no risk of the conventionally known phenomenon of pattern heads becoming rounded, reducing resolution and deteriorating LER. On the other hand, when Mw is 50,000 or less, there is no risk of LER degradation, particularly when forming a pattern with a line width of 100 nm or less. In the present invention, Mw is a polystyrene-equivalent value measured by gel permeation chromatography (GPC) using THF or DMF as a solvent.

[0143] The polymer preferably has a narrow molecular weight distribution (Mw / Mn) of 1.0 to 2.0, preferably 1.0 to 1.9, and more preferably 1.0 to 1.8. When the polymer has such a narrow distribution, foreign matter is not generated on the pattern after development, and the pattern shape is not deteriorated.

[0144] Furthermore, the base polymer is designed to have a dissolution rate in an alkaline developer of preferably 10 nm / min or less, more preferably 7 nm / min or less, and even more preferably 5 nm / min or less. In advanced-generation photomasks, when the coating film on the substrate is thin (100 nm or less), the pattern is significantly affected by pattern film loss during alkaline development. If the polymer's alkaline dissolution rate exceeds 10 nm / min, the pattern collapses, making it impossible to form fine patterns. This is particularly true in the production of photomasks, which require a defect-free design, since the development process tends to be intense. In this invention, the dissolution rate of the base polymer in an alkaline developer was calculated from the film loss observed when an 8-inch silicon wafer was spin-coated with a polymer solution (polymer concentration: 16.7 wt %, solvent: propylene glycol monomethyl ether acetate (PGMEA)), baked at 100°C for 90 seconds to form a 1000 nm-thick film, and then developed at 23°C for 100 seconds with a 2.38 wt % aqueous solution of tetramethylammonium hydroxide (TMAH).

[0145] The base polymer of component (A) may contain a polymer other than the above-mentioned polymer. As the other polymer, a conventionally known base polymer for a resist composition can be used. The content of the other polymer is not particularly limited as long as it does not impair the effects of the present invention.

[0146] [(B) Quencher] The chemically amplified positive resist composition of the present invention may optionally contain a quencher as component (B). In this specification, a quencher refers to a compound that traps the acid generated from the acid generator. This can suppress the rate at which the acid generated from the acid generator diffuses into the resist film. Even when a substrate is used whose outermost surface is made of a material containing chromium, the effect of the acid generated within the resist film on the chromium-containing material can be suppressed.

[0147] Examples of the quencher include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A are preferred, including amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond, and compounds having a carbamate group described in JP 3790649 A. Preferred examples include tris[2-(methoxymethoxy)ethyl]amine, tris[2-(methoxymethoxy)ethyl]amine-N-oxide, dibutylaminobenzoic acid, morpholine derivatives, imidazole derivatives, etc. Addition of such basic compounds can, for example, further suppress the diffusion rate of acid in the resist film or correct the shape.

[0148] Further, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of carboxylic acids not fluorinated at the α-position, as described in JP-A-2008-158339. Sulfonic acids, imide acids, or methide acids fluorinated at the α-position are necessary for deprotecting acid labile groups, and salt exchange with onium salts not fluorinated at the α-position releases carboxylic acids not fluorinated at the α-position. Carboxylic acids not fluorinated at the α-position hardly undergo deprotection reactions, and therefore function as quenchers.

[0149] Examples of onium salts of carboxylic acids that are not fluorinated at the α-position include those represented by the following formula (B1). [ka]

[0150] In formula (B1), R 101 represents a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the carboxy group is substituted with a fluorine atom or a fluoroalkyl group.

[0151] R 101 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0]. 2,6]Cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms such as a decyl group, an adamantyl group, and an adamantylmethyl group; alkenyl groups having 2 to 40 carbon atoms such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 40 carbon atoms such as a cyclohexenyl group; phenyl group, naphthyl group, alkylphenyl groups (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, Examples of aryl groups include aryl groups having 6 to 40 carbon atoms such as arylphenyl groups (e.g., 2,4-n-butylphenyl group, 4-n-butylphenyl group), di- or trialkylphenyl groups (e.g., 2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group), alkylnaphthyl groups (e.g., methylnaphthyl group, ethylnaphthyl group), and dialkylnaphthyl groups (e.g., dimethylnaphthyl group, diethylnaphthyl group); and aralkyl groups having 7 to 40 carbon atoms such as benzyl group, 1-phenylethyl group, and 2-phenylethyl group.

[0152] Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH- groups of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. Examples of the hydrocarbyl group containing a heteroatom include heteroaryl groups such as a thienyl group; alkoxyphenyl groups such as a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-tert-butoxyphenyl group, and a 3-tert-butoxyphenyl group; alkoxynaphthyl groups such as a methoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthyl group, and an n-butoxynaphthyl group; dialkoxynaphthyl groups such as a dimethoxynaphthyl group and a diethoxynaphthyl group; and aryloxoalkyl groups such as a 2-aryl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a 2-(2-naphthyl)-2-oxoethyl group.

[0153] In formula (B1), Mq A + is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation, or an ammonium cation, and more preferably a sulfonium cation or an iodonium cation. Specific examples of the sulfonium cation include, but are not limited to, those described in paragraphs

[0102] to

[0125] of JP-A No. 2024-003744, those described in paragraphs

[0070] to

[0085] of JP-A No. 2023-169812, and those represented by formula (A2). Specific examples of the iodonium cation include, but are not limited to, those described in paragraph

[0181] of JP-A No. 2024-000259.

[0154] Examples of the anion of the onium salt represented by formula (B1) include, but are not limited to, those shown below. [ka]

[0155] [ka]

[0156] [ka]

[0157] As the quencher, a sulfonium salt of an iodinated benzene ring-containing carboxylic acid represented by the following formula (B2) can also be suitably used. [ka]

[0158] In formula (B2), s is 1, 2, 3, 4, or 5. t is 0, 1, 2, or 3, provided that 1≦s+t≦5. u is 1, 2, or 3.

[0159] In formula (B2), R 111 represents a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which some or all of the hydrogen atoms may be substituted with halogen atoms, or -N(R 111A )-C(=O)-R 111B or -N(R 111A )-C(=O)-OR 111B R 111A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 111Bis a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms. When t and / or u is 2 or more, each R 111 may be the same or different from each other.

[0160] In formula (B2), L 1 is a single bond or a (u+1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, and a carboxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic.

[0161] In formula (B2), R 112 , R 113 and R 114 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. Some or all of the hydrogen atoms in the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, an oxo group, a cyano group, a nitro group, a sultone ring, a sulfo group, or a sulfonium salt-containing group. Some of the -CH2- groups in the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate ester bond. Furthermore, R 112 and R 113 may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0162] Specific examples of the compound represented by formula (B2) include those described in JP 2017-219836 A. The compound represented by formula (B2) has high absorption, a high sensitizing effect, and a high acid diffusion control effect.

[0163] As the quencher, a nitrogen atom-containing carboxylate compound represented by the following formula (B3) can also be used. [ka]

[0164] In formula (B3), R 121 ~R 124 are each independently a hydrogen atom, -L 2 -CO2 - or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. 121 and R 122 and R 122 and R 123 and, or R 123 and R 124 and may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 2 R is a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 125 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom.

[0165] In formula (B3), ring R r is a ring containing carbon atoms and nitrogen atoms and having 2 to 6 carbon atoms, and some or all of the hydrogen atoms bonded to the carbon atoms of the ring are hydrocarbyl groups having 1 to 20 carbon atoms, or -L 2 -CO2 - and some of the carbon atoms of the ring may be substituted with sulfur atoms, oxygen atoms, or nitrogen atoms. The ring may be an alicyclic ring or an aromatic ring, and is preferably a 5- or 6-membered ring, specific examples of which include a pyridine ring, a pyrrole ring, a pyrrolidine ring, a piperidine ring, a pyrazole ring, an imidazoline ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an imidazoline ring, an oxazole ring, a thiazole ring, a morpholine ring, a thiazine ring, and a triazole ring.

[0166] The onium carboxylic acid salt represented by formula (B3) has at least one -L 2 -CO2 - group, i.e., R 121 ~R 124 At least one of the 2 -CO2 - and / or at least one of the hydrogen atoms bonded to the carbon atom of the ring R is -L 2 -CO2 - is replaced by

[0167] In formula (B3), Mq B + is a sulfonium cation, an iodonium cation, or an ammonium cation, preferably a sulfonium cation. Specific examples of the sulfonium cation include those described in paragraphs

[0102] to

[0125] of JP-A No. 2024-003744, those described in paragraphs

[0070] to

[0085] of JP-A No. 2023-169812, and those represented by formula (A2), but are not limited thereto.

[0168] Examples of the anion of the compound represented by formula (B3) include, but are not limited to, those shown below. [ka]

[0169] [ka]

[0170] [ka]

[0171] [ka]

[0172] [ka]

[0173] [ka]

[0174] Furthermore, a weak acid betaine type compound can also be used as the quencher. Specific examples thereof include, but are not limited to, the following: [ka]

[0175] Further examples of the quencher include the polymer-type quencher described in JP 2008-239918 A. This quencher enhances the rectangularity of the resist pattern by orienting on the surface of the resist film. The polymer-type quencher also has the effect of preventing pattern film loss and pattern top rounding when a protective film for immersion lithography is applied.

[0176] When the chemically amplified positive resist composition of the present invention contains a quencher, the content thereof is preferably from 0 to 50 parts by mass, and more preferably from 0.1 to 40 parts by mass, relative to 80 parts by mass of the base polymer. The quenchers may be used singly or in combination of two or more.

[0177] [(C) Organic solvent] The resist composition of the present invention may contain an organic solvent as component (C). There are no particular limitations on the organic solvent, so long as it is capable of dissolving each component. Examples of such organic solvents include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] and

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

[0178] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, and mixed solvents thereof are preferred.

[0179] When the chemically amplified positive resist composition of the present invention contains an organic solvent (C), the content thereof is preferably 200 to 10,000 parts by mass, and more preferably 400 to 5,000 parts by mass, relative to 80 parts by mass of the base polymer (B). The organic solvent (C) may be used alone, or two or more types may be mixed and used.

[0180] [(D) Fluorine atom-containing polymer] The chemically amplified positive resist composition of the present invention may contain, as component (D), a fluorine-containing polymer containing at least one repeating unit selected from the group consisting of a repeating unit represented by formula (D1) (hereinafter also referred to as repeating unit D1), a repeating unit represented by formula (D2) (hereinafter also referred to as repeating unit D2), a repeating unit represented by formula (D3) (hereinafter also referred to as repeating unit D3), and a repeating unit represented by formula (D4) (hereinafter also referred to as repeating unit D4), for the purposes of achieving high contrast, suppressing the chemical flare phenomenon of acids caused by high-energy radiation exposure, shielding acid from mixing from the antistatic coating during the process of applying an antistatic coating material to the resist film, and suppressing unexpected and unnecessary pattern degradation. The fluorine-containing polymer also functions as a surfactant, preventing insoluble matter from redepositing onto the substrate during the development process, thereby effectively reducing development defects. [ka]

[0181] In the formulas (D1) to (D4), h is 1, 2, or 3. B are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 201 , R 202 , R 204 and R 205 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. 203 , R 206 , R 207 and R 208 are each independently a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group, and R 203 , R 206 , R 207 and R 208 When Z is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bond. 1is a (h+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (h+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. * represents a bond to a carbon atom in the main chain.

[0182] R 201 , R 202 , R 204 and R 205 The saturated hydrocarbyl group having 1 to 10 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl. Of these, saturated hydrocarbyl groups having 1 to 6 carbon atoms are preferred.

[0183] R 203 , R 206 , R 207 and R 208 The hydrocarbyl group having 1 to 15 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, and an alkynyl group having 2 to 15 carbon atoms, with an alkyl group having 1 to 15 carbon atoms being preferred. Examples of the alkyl group include those mentioned above, as well as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, and n-pentadecyl. Examples of the fluorinated hydrocarbyl group include groups in which some or all of the hydrogen atoms bonded to carbon atoms in the hydrocarbyl group mentioned above have been substituted with fluorine atoms.

[0184] Z 1Examples of the (h+1)-valent hydrocarbon group having 1 to 20 carbon atoms and represented by the formula (I) include a group in which k hydrogen atoms have been further removed from an alkyl group having 1 to 20 carbon atoms or a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms. 1 Examples of the (h+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms and represented by the formula (I) include groups in which at least one hydrogen atom of the aforementioned (h+1)-valent hydrocarbon group has been substituted with a fluorine atom.

[0185] Specific examples of the repeating units D1 to D4 include, but are not limited to, the following: B is the same as above. [ka]

[0186] [ka]

[0187] [ka]

[0188] Furthermore, it is preferable that the fluorine atom-containing polymer further contains at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (D5) (hereinafter also referred to as repeating unit D5) and a repeating unit represented by the following formula (D6) (hereinafter also referred to as repeating unit D6). [ka]

[0189] In formulas (D5) and (D6), x is 1, 2, or 3. y is an integer satisfying 0≦y≦5+2z−x. z is 0 or 1. R C are each independently a hydrogen atom or a methyl group. 209R is a hydrogen atom or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a heteroatom-containing group interposed between its carbon-carbon bond. 210 R is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms, which may have a heteroatom-containing group interposed between its carbon-carbon bond. 211 is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom has been substituted with a fluorine atom, and some of the -CH2- groups in the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. 3 is a single bond, -O-, *-C(=O)-OZ 31 -Z 32 -or*-C(=O)-NH-Z 31 -Z 32 -It is. Z 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 is a single bond, an ester bond, an ether bond, or a sulfonamide bond. * is a bond to a carbon atom of the main chain.

[0190] R 209 and R 210 Examples of the hydrocarbyl group having 1 to 5 carbon atoms represented by the formula (I) include an alkyl group, an alkenyl group, and an alkynyl group, with an alkyl group being preferred. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and an n-pentyl group. In addition, a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom may be present between the carbon-carbon bonds of the hydrocarbyl group.

[0191] -OR in formula (D5) 209 is preferably a hydrophilic group. In this case, R 209 As the alkyl group, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms and an oxygen atom intervening between the carbon-carbon bonds, and the like are preferred.

[0192] R 211The saturated hydrocarbyl group having 1 to 20 carbon atoms, represented by the formula (I) above, in which at least one hydrogen atom has been substituted with a fluorine atom, may be linear, branched, or cyclic, and specific examples thereof include an alkyl group having 1 to 20 carbon atoms or a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms in which at least one hydrogen atom has been substituted with a fluorine atom.

[0193] Z 2 is preferably *-C(=O)-O- or *-C(=O)-NH-. C is preferably a methyl group. 2 The presence of a carbonyl group in R improves the acid trapping ability of the antistatic film. C When the methyl group is used, the polymer becomes more rigid with a higher glass transition temperature (Tg), which suppresses acid diffusion, resulting in good stability of the resist film over time and preventing degradation of resolution and pattern shape.

[0194] Z 3 The saturated hydrocarbylene group having 1 to 10 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, a propane-2,2-diyl group, a butane-1,1-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-2,3-diyl group, a butane-1,4-diyl group, and a 1,1-dimethylethane-1,2-diyl group.

[0195] Examples of the repeating unit D5 include, but are not limited to, those shown below. C is the same as above. [ka]

[0196] [ka]

[0197] Examples of the repeating unit D6 include, but are not limited to, those shown below. C is the same as above. [ka]

[0198] [ka]

[0199] [ka]

[0200] [ka]

[0201] The content of repeating units D1 to D4 is preferably 15 to 95 mol %, more preferably 20 to 85 mol %, of all repeating units in the fluorine atom-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 in the fluorine atom-containing polymer. The repeating units D1 to D6 may be used alone or in combination of two or more.

[0202] The (D) fluorine atom-containing polymer may contain repeating units other than the repeating units described above. Examples of such repeating units include those described in paragraphs

[0046] to

[0078] of JP 2014-177407 A. When the (D) fluorine atom-containing polymer contains other repeating units, the content of such other repeating units is preferably 50 mol % or less of all repeating units of the fluorine atom-containing polymer.

[0203] (D) The fluorine atom-containing polymer can be synthesized by copolymerizing each monomer, optionally protected with a protecting group, according to a known method, followed by a deprotection reaction as needed. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, reference can be made to JP-A-2004-115630.

[0204] The Mw of the (D) fluorine atom-containing polymer is preferably 2,000 to 50,000, more preferably 3,000 to 20,000. When the Mw is 2,000 or more, the acid does not diffuse, the resolution does not deteriorate, and the stability over time is not impaired. When the Mw is 50,000 or less, the solubility in solvents is sufficient and coating defects do not occur. Furthermore, the (D) fluorine atom-containing polymer preferably has an Mw / Mn ratio of 1.0 to 2.2, more preferably 1.0 to 1.7.

[0205] When the chemically amplified positive resist composition of the present invention contains (D) a fluorine atom-containing polymer, the content thereof is preferably from 0.01 to 30 parts by mass, and more preferably from 0.1 to 20 parts by mass, relative to 80 parts by mass of the (A) base polymer. The (D) fluorine atom-containing polymer may be used alone, or two or more types may be used in combination.

[0206] [(E) Photoacid generator] The chemically amplified positive resist composition of the present invention may contain a photoacid generator as component (E). There are no particular limitations on the photoacid generator, as long as it is a compound that generates an acid upon exposure to high-energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators.

[0207] Specific examples of the photoacid generator include nonafluorobutanesulfonate, the partially fluorinated sulfonates described in paragraphs

[0247] to

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

[0261] to

[0265] of JP 2013-101271 A, and those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A and paragraphs

[0080] to

[0081] of JP 2010-215608 A. Among the specific examples, arenesulfonate- or alkanesulfonate-type photoacid generators are preferred because they generate an acid of appropriate strength for deprotecting the acid labile group in the repeating unit A3.

[0208] As such a photoacid generator, a salt compound containing the anion shown below is preferred. [ka]

[0209] [ka]

[0210] [ka]

[0211] [ka]

[0212] [ka]

[0213] [ka]

[0214] [ka]

[0215]

change

[0216]

change

[0217]

change

[0218]

change

[0219]

change

[0220]

change

[0221]

change

[0222]

change

[0223]

change

[0224]

change

[0225]

change

[0226]

change

[0227]

change

[0228]

change

[0229]

change

[0230]

change

[0231]

change

[0232]

change

[0233]

change

[0234]

change

[0235]

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[0236]

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[0449] [ka]

[0450] Furthermore, as the photoacid generator, a salt compound containing an anion represented by the following formula (E1) is also preferred. [ka]

[0451] In formula (E1), m1 is 0 or 1. p is 1, 2, or 3. q is 1, 2, 3, 4, or 5. r is 0, 1, 2, or 3, provided that 1≦q+r≦5.

[0452] In formula (E1), L 11 is a single bond, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond.

[0453] In formula (E1), L 12 is an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond.

[0454] In formula (E1), L C represents a single bond or a hydrocarbylene group having 1 to 20 carbon atoms when p is 1, and represents a (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms when p is 2 or 3, and the hydrocarbylene group and the (p+1)-valent hydrocarbon group 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 hydroxy group, and a carboxy group.

[0455] L CThe hydrocarbylene group having 1 to 20 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, and a dodecane-1,12-diyl group. alkanediyl groups having 1 to 20 carbon atoms; cyclic saturated hydrocarbylene groups having 3 to 20 carbon atoms such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group; unsaturated aliphatic hydrocarbylene groups having 2 to 20 carbon atoms such as vinylene group and propene-1,3-diyl group; arylene groups having 6 to 20 carbon atoms such as phenylene group and naphthylene group; and groups obtained by combining these. C The (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms, represented by the formula (1), may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include groups obtained by further removing one or two hydrogen atoms from the specific examples of the hydrocarbylene group having 1 to 20 carbon atoms described above.

[0456] In formula (E1), Rf 1 and Rf 2 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that at least one is a fluorine atom or a trifluoromethyl group.

[0457] In formula (E1), R 301 is a hydroxy group, a carboxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, -N(R 301A )(R 301B ), -N(R 301C )-C(=O)-R 301D or -N(R 301C )-C(=O)-OR 301D R 301Aand R 301B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 301C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 301D is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms.

[0458] R 301 , R 301A , R 301B and R 301C The saturated hydrocarbyl group having 1 to 6 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl groups; and cyclic saturated hydrocarbyl groups having 3 to 6 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups. 301 Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group having 1 to 6 carbon atoms and represented by the formula (I) include the same as the specific examples of the saturated hydrocarbyl group described above, and R 301 Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms represented by the formula include those having 1 to 5 carbon atoms among the specific examples of the saturated hydrocarbyl groups having 1 to 6 carbon atoms mentioned above.

[0459] R 301D The unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkenyl groups having 2 to 8 carbon atoms such as vinyl, propenyl, butenyl, and hexenyl groups; alkynyl groups having 2 to 8 carbon atoms such as ethynyl, propynyl, and butynyl groups; and cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 8 carbon atoms such as cyclohexenyl and norbornenyl groups.

[0460] In formula (E1), R 302represents a saturated hydrocarbylene group having 1 to 20 carbon atoms or an arylene group having 6 to 20 carbon atoms, and some or all of the hydrogen atoms of the saturated hydrocarbylene group may be substituted with halogen atoms other than fluorine atoms, or some or all of the hydrogen atoms of the arylene group may be substituted with a substituent selected from a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogen atom, and a hydroxy group.

[0461] R 302 The hydrocarbylene group having 1 to 20 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. C Examples of the hydrocarbylene group having 1 to 20 carbon atoms represented by the following formula include the same as those exemplified above.

[0462] R 302 Specific examples of the arylene group having 6 to 20 carbon atoms represented by the formula (I) include a phenylene group, a naphthylene group, a phenanthrenediyl group, and an anthracenediyl group. The hydrocarbyl moiety of the saturated hydrocarbyl group having 1 to 20 carbon atoms and the hydrocarbyloxy group having 1 to 20 carbon atoms, which are substituents on the arylene group, may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and icosyl group; and cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, and adamantyl group. Specific examples of the arylene group having 6 to 14 carbon atoms that is the substituent of the arylene group include a phenylene group, a naphthylene group, a phenanthrenediyl group, and an anthracenediyl group.

[0463] The anion represented by formula (E1) is preferably an anion represented by the following formula (E2). [ka]

[0464] In formula (E2), p, q, r, L 11 , L C and R 301 is the same as above. m2 is 1, 2, 3 or 4. R 302A is a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, a halogen atom, or a hydroxy group. When m2 is 2, 3, or 4, each R 302A may be the same as or different from each other.

[0465] Specific examples of the anion represented by formula (E1) include, but are not limited to, those shown below. [ka]

[0466] [ka]

[0467] [ka]

[0468] [ka]

[0469] [ka]

[0470] [ka]

[0471]

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[0502] In the (E) photoacid generator, the cation paired with the anion is preferably a sulfonium cation or an iodonium cation. Specific examples of the sulfonium cation include, but are not limited to, those described in paragraphs

[0102] to

[0125] of JP-A No. 2024-003744, those described in paragraphs

[0070] to

[0085] of JP-A No. 2023-169812, and those represented by formula (A2). Specific examples of the iodonium cation include, but are not limited to, those described in paragraph

[0181] of JP-A No. 2024-000259.

[0503] The acid generated by the photoacid generator preferably has a pKa of -2.0 or higher, more preferably -1.0 or higher. The upper limit of the pKa is preferably 2.0. The pKa value was calculated using the pKa DB in the software ACD / Chemsketch ver. 9.04 manufactured by Advanced Chemistry Development, Inc.

[0504] When the chemically amplified positive resist composition of the present invention contains a photoacid generator (E), the content thereof is preferably 1 to 10 parts by mass, more preferably 1 to 5 parts by mass, relative to 80 parts by mass of the base polymer. By including the photoacid generator (E), it is possible to appropriately adjust the amount of acid generated in the exposed area and the dissolution inhibition ability of the unexposed area. The photoacid generator (E) may be used alone or in combination of two or more types.

[0505] When the chemically amplified positive resist composition of the present invention contains both (E) a photoacid generator and (B) a quencher, the content ratio of the photoacid generator to the quencher (photoacid generator / quencher) is preferably less than 3 by mass, more preferably less than 2.5, and even more preferably less than 2. When the content ratio of the photoacid generator to the quencher contained in the chemically amplified positive resist composition is within the above range, acid diffusion can be sufficiently suppressed, and excellent resolution and dimensional uniformity can be obtained.

[0506] [(F) Surfactant] The chemically amplified positive resist composition of the present invention may contain a commonly used surfactant as component (F) in order to improve its coatability onto a substrate. Many such surfactants are known, as described in WO 2006 / 121096, JP 2008-102383, JP 2008-304590, JP 2004-115630, and JP 2005-8766, and a surfactant can be selected with reference to these publications.

[0507] When the chemically amplified positive resist composition of the present invention contains a surfactant (F), the content thereof is preferably 2 parts by mass or less, more preferably 1 part by mass or less, and the lower limit thereof is preferably 0.01 part by mass or more, relative to 80 parts by mass of the base polymer (A). The surfactant (F) may be used alone, or two or more types may be used in combination.

[0508] [Method for forming resist pattern] The method for forming a resist pattern of the present invention includes the steps of forming a resist film on a substrate using the aforementioned chemically amplified positive resist composition, exposing the resist film to high-energy rays, and developing the pattern-irradiated resist film using an alkaline developer to obtain a resist pattern.

[0509] The substrate may be, for example, a substrate for manufacturing integrated circuits (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coating, etc.) or a substrate for manufacturing mask circuits (Cr, CrO, CrON, MoSi2, Si, SiO2, SiO2, etc.) The chemically amplified positive resist composition is applied to the substrate by a method such as spin coating to a film thickness of 0.03 to 2 μm, and this is then pre-baked on a hot plate preferably at 60 to 150°C for 1 to 20 minutes, more preferably at 80 to 140°C for 1 to 10 minutes, to form a resist film.

[0510] The resist film is then exposed to a pattern using high-energy radiation such as ultraviolet radiation, far ultraviolet radiation, excimer laser light (e.g., KrF or ArF), EB, EUV, X-rays, gamma rays, and synchrotron radiation.

[0511] When ultraviolet rays, far ultraviolet rays, excimer laser light, EUV, X-rays, gamma rays, or synchrotron radiation is used as the high-energy rays, a mask for forming a desired pattern is used, and the exposure dose is preferably 1 to 300 mJ / cm. 2 , more preferably 10 to 200 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 1 to 300 μC / cm 2 , more preferably 10 to 200 μC / cm 2 The chemically amplified positive resist composition of the present invention is particularly useful for EUV or EB lithography.

[0512] Exposure can be performed by conventional exposure methods, or in some cases by immersion, in which a liquid is inserted between the mask and the resist film. In this case, a water-insoluble protective film can be used.

[0513] Next, post-exposure baking (PEB) is carried out on a hot plate, preferably at 60 to 150° C. for 1 to 20 minutes, more preferably at 80 to 140° C. for 1 to 10 minutes.

[0514] Thereafter, the substrate is developed using a developer, preferably an aqueous alkaline solution of 0.1 to 5 mass %, more preferably 2 to 3 mass %, tetramethylammonium hydroxide (TMAH) or the like, for 0.1 to 3 minutes, preferably 0.5 to 2 minutes, by a conventional method such as dipping, puddling, or spraying, to form a desired pattern on the substrate.

[0515] The chemically amplified positive resist composition of the present invention is particularly useful when used under conditions requiring high etching resistance, small change in pattern line width even when the time until PEB after exposure is extended, and small LER. The resist composition of the present invention is also particularly useful for application to substrates having a surface made of a material that is prone to pattern peeling or pattern collapse due to the difficulty in achieving resist pattern adhesion. Examples of such substrates include substrates on which a film of metallic chromium or a chromium compound containing one or more light elements selected from oxygen, nitrogen, and carbon is sputtered. The chemically amplified positive resist composition of the present invention is particularly useful for pattern formation using a photomask blank as the substrate. [Example]

[0516] The present invention will be specifically explained below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. The copolymerization composition ratios are molar ratios, and Mw is a polystyrene-equivalent measurement value obtained by GPC. The following apparatuses were used. IR: Thermo Fisher Scientific NICOLET 6700 · 1 H-NMR: ECA-500 manufactured by JEOL Ltd. MALDI TOF-MS: JEOL S3000

[0517] [1] Synthesis of onium salt monomers [Synthesis Example 1-1] Synthesis of onium salt monomer A1-1 [ka]

[0518] Under a nitrogen atmosphere, an aqueous solution of the raw material SM-1 (1046.2 g, equivalent to 47.1 g of pure content), the raw material SM-2 (21.6 g), and methylene chloride (300 g) were charged and stirred at room temperature for 30 minutes. The organic layer was separated, washed with water, and then concentrated under reduced pressure to obtain the onium salt monomer A1-1 as an oil (yield: 56.7 g, 93%).

[0519] The IR spectrum data and TOF-MS results of the onium salt monomer A1-1 are shown below. 1 The results of H-NMR / DMSO-d6) are shown in Figure 1. IR(D-ATR): ν= 3436, 3060, 1706, 1599, 1560, 1495, 1443, 1387, 1294, 1200, 1134, 1123, 1055, 1033, 1009, 999, 912, 864, 844, 733, 719, 699, 675, 581, 555, 539, 508, 491 cm -1 . MALDI TOF-MS: POSITIVE M + 461(C 18 H 10 F4IS + equivalent) NEGATIVE M - 183(C8H7O3S - equivalent)

[0520] [2] Polymer synthesis [Synthesis Example 2-1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, a flask was charged with 19.2 g of Monomer A1-1, 50.1 g of Monomer A2-1, 30.7 g of Monomer A3-1-1, 6.86 g of V-601 (Fujifilm Wako Pure Chemical Industries, Ltd.), and 139 g of MEK to prepare a monomer-polymerization initiator solution. 46 g of MEK was charged to a separate flask under a nitrogen atmosphere and heated to 80°C with stirring. The monomer-polymerization initiator solution was then added dropwise over 4 hours. After the addition was complete, the polymerization solution was stirred for 2 hours while maintaining the temperature at 80°C, and then cooled to room temperature. The resulting polymerization solution was added dropwise to 3,000 g of vigorously stirred hexane, and the precipitated polymer was filtered off. The resulting polymer was washed twice with 600 g of hexane and then vacuum-dried at 50°C for 20 hours to obtain Polymer P-1 as a white powder (yield: 97.1 g, 97%). Polymer P-1 had an Mw of 9700 and an Mw / Mn of 1.62. Note that Mw was measured in terms of polystyrene by GPC using DMF as a solvent. [ka]

[0521] [Synthesis Examples 2-2 to 2-60, Comparative Synthesis Examples 1-1 to 1-38] Synthesis of polymers P-2 to P-60 and comparative polymers CP-1 to CP-38 Polymers P-2 to P-60 shown in Tables 1 and 2 below, and comparative polymers CP-1 to CP-38 shown in Table 3 below, were synthesized in the same manner as in Synthesis Example 2-1, except that the type and compounding ratio of each monomer was changed. In Tables 1 to 3 below, the introduction ratio indicates the molar ratio.

[0522] [Table 1]

[0523] [Table 2]

[0524] [Table 3]

[0525] The monomers used in the synthesis of the polymer are as follows: [ka]

[0526] [ka]

[0527] [ka]

[0528] [ka]

[0529] [ka]

[0530] [ka]

[0531] [ka]

[0532] The dissolution rates of the polymers in alkaline developers were calculated by spin-coating a polymer solution (polymer concentration: 16.7% by mass, solvent: PGME) onto an 8-inch silicon wafer, baking it at 100°C for 90 seconds to form a film with a thickness of 1000 nm, developing it in a 2.38% by mass aqueous TMAH solution at 23°C for 100 seconds, and measuring the amount of film loss. As a result, the dissolution rates of polymers P-1 to P-60 were 10 nm / min or less. Furthermore, the dissolution rates of comparative polymers CP-1 to CP-38 were 10 nm / min or less.

[0533] [Synthesis Examples 3-1 to 3-16] Synthesis of Polymers AP-1 to AP-16 Polymers AP-1 to AP-16 shown below were synthesized in the same manner as in Synthesis Example 1-1, except that the raw material compounds used were changed. [ka]

[0534] [ka]

[0535] [ka]

[0536] [ka]

[0537] The dissolution rates of polymers AP-1 to AP-16 were 10 nm / min or less.

[0538] [2] Preparation of chemically amplified positive resist composition [Examples 1-1 to 1-100, Comparative Examples 1-1 to 1-60] Chemically amplified positive resist compositions were prepared by dissolving each component in an organic solvent according to the formulations shown in Tables 4 to 8 below, and filtering the resulting solution through a 5 nm nylon filter and a sub-1 nm UPE filter. The organic solvent was a mixed solvent of 920 parts by mass of PGMEA and 1850 parts by mass of EL, or 1850 parts by mass of diacetone alcohol and 1850 parts by mass of PGME.

[0539] [Table 4]

[0540] [Table 5]

[0541] [Table 6]

[0542] [Table 7]

[0543] [Table 8]

[0544] In Tables 4 to 8, the structures of quenchers Q-1 to Q-5, photoacid generators PAG-1 to PAG-6, and polymers FP-1 to FP-5 are as follows: [ka]

[0545] [ka]

[0546] [ka]

[0547] [3] EB lithography evaluation [Examples 2-1 to 2-100, Comparative Examples 2-1 to 2-60] Each chemically amplified positive resist composition (R-1 to R-100, CR-1 to CR-60) was spin-coated using ACT-M (Tokyo Electron Limited) onto a 152 mm square reflective mask blank for EUV exposure masks, the outermost surface of which was a chromium compound, and the mask was pre-baked on a hot plate at 110°C for 600 seconds to produce a resist film with a thickness of 80 nm. The thickness of the resulting resist film was measured using an optical measuring device, Nanospec (Nanometrics). Measurements were performed at 81 locations within the surface of the blank substrate, excluding the outer edge portion extending 10 mm inward from the outer periphery, and the average thickness and thickness range were calculated.

[0548] Next, the film was exposed using an electron beam exposure device (EBM-5000plus manufactured by NuFlare Technology, Inc., acceleration voltage 50 kV), subjected to PEB at 110°C for 600 seconds, and developed with a 2.38% by mass TMAH aqueous solution to obtain a positive pattern.

[0549] The obtained resist patterns were evaluated as follows: The prepared patterned mask blanks were observed with a top-down SEM (scanning electron microscope), and the exposure dose required to resolve a 200 nm 1:1 line and space (LS) at 1:1 was determined as the optimal exposure dose (μC / cm 2The minimum dimension at the exposure dose required to resolve a 200 nm line-and-space pattern at a 1:1 ratio was taken as the resolution (limiting resolution), and the LER of the 200 nm line-and-space pattern was measured using an SEM. Regarding the limiting resolution of isolated spaces (IS), the minimum dimension at the exposure dose required to resolve a 200 nm line-and-space pattern at a 9:1 ratio was taken as the limiting resolution. The pattern shape was visually determined to be rectangular or not. The results are shown in Tables 9 to 13.

[0550] [Table 9]

[0551] [Table 10]

[0552] [Table 11]

[0553] [Table 12]

[0554] [Table 13]

[0555] [4] Etching resistance evaluation [Examples 3-1 to 3-6, Comparative Examples 3-1 to 3-4] Each chemically amplified positive resist composition (R-2, R-7 to R-11, CR-2, CR-7 to CR-9) was spin-coated onto a 152 mm square reflective mask blank for EUV exposure masks, the outermost surface of which was a chromium compound, using an ACT-M (Tokyo Electron Limited) coating. The coating was then pre-baked on a hot plate at 110°C for 600 seconds to produce a 120 nm thick resist film. The thickness of the resulting resist film was measured using an optical measuring device, Nanospec (Nanometrics). Measurements were performed at 81 locations on the blank substrate, excluding the outer edge extending 10 mm inward from the outer periphery, and the average thickness and thickness range were calculated. The resulting coated substrate was dry-etched using a dry etching system (UNAXIS G4) under the following conditions, and the film loss rate (A / sec) was calculated from the remaining film after etching. The results are shown in Table 11.

[0556] RF1(RIE): Pulse 700V RF2(ICP):CW 400W Pressure: 6mTorr Cl2: 185sccm O2: 55sccm He: 9.25 sccm Etching time: 75 seconds

[0557] [Table 14]

[0558] The chemically amplified positive resist compositions (R-1 to R-100) of the present invention all exhibited good resolution, LER, and pattern rectangularity. On the other hand, the comparative resist compositions (CR-1 to CR-60) exhibited insufficient optimization of acid diffusion, resulting in degradation of resolution, LER, and pattern rectangularity. Furthermore, dry etching evaluation using R-2, R-7 to R-11 also showed better etching resistance than CR-2, CR-7 to CR-9, suggesting that the inclusion of the skeleton of formula (A1) of the present invention in the polymer is effective in mask processing.

[0559] The method of forming a resist pattern using the chemically amplified positive resist composition of the present invention is useful in the production of semiconductor devices, particularly in photolithography in the processing of transmission and reflection photomask blanks.

Claims

1. A chemically amplified positive resist composition comprising: a base polymer (A) containing a polymer whose solubility in an alkaline aqueous solution increases under the action of an acid, the base polymer (A) comprising a repeating unit composed of an aromatic sulfonate anion represented by the following formula (A1-1) and a sulfonium cation represented by the following formula (A1-2), and a repeating unit represented by the following formula (A2), wherein the base polymer (A) contains a repeating unit composed of an aromatic sulfonate anion represented by the following formula (A1-1) and a sulfonium cation represented by the following formula (A1-2): 【Chemistry 1】 (In the formula, n1 is 0 or 1. When n1 is 0, n2 is 0, 1, 2, 3, or 4, and when n1 is 1, n2 is 0, 1, 2, 3, 4, 5, or 6. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 1 is a halogen atom, a nitro group, a cyano group, a hydroxy group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. 1 may be the same or different, and multiple R 1 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. X 1 is a single bond, an ether bond, an ester bond, or an amide bond. 【Chemistry 2】 (Wherein, m1 is 0 or 1. m2 is 0 or 1. m3 is 0 or 1. m4 is 0, 1, 2, 3 or 4. m5 is 0, 1, 2, 3 or 4. m6 is 0, 1, 2, 3, 4, 5 or 6. m7 is 0, 1, 2, 3, 4, 5 or 6. m8 is 0, 1 or 2. m9 is 0, 1 or 2. m10 is 0, 1 or 2. m11 is 0 or 1. m12 is 0, 1, 2, 3 or 4. m13 is 0, 1 or 2. m14 is 0, 1 or 2. However, when m1 is 0, 0≦m6+m9≦4, and when m1 is 1, 0≦m6+m9≦6. When m2 is 0, 0≦m7+m10≦4, and when m2 is 1, 0≦m7+m10≦6. When m3 is 0, 1≦m4+m5+m8+m14≦4, and when m13 is 1, 1≦m4+m5+m8+m14≦6. When m11 is 0, 0≦m12+m13≦4, and when m11 is 1, 0≦m12+m13≦6. Also, m4+m12≧1. R F1 ~R F3 are each independently a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms. F1 may be the same or different, and when m6 is 2 or more, each R F2 may be the same or different, and when m7 is equal to or greater than 1, each R F3 may be the same or different from each other. R 2 ~R 5 is a halogen atom other than an iodine atom or a fluorine atom, a nitro group, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may contain a heteroatom, or a hydrocarbylthio group having 1 to 20 carbon atoms which may contain a heteroatom. 2 may be the same or different, and two R 2 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. When m9 is 2, two R 3 may be the same or different, and two R 3 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 4 may be the same or different, and two R 4 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 5 may be the same or different, and two R 5 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. In addition, S in the sulfonium cation + The aromatic rings directly bonded to S + may form a ring together with L A and L B are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate ester bond, a sulfonamide bond, a carbonate bond or a carbamate bond. X L is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. 【Transformation 3】 (In the formula, a1 is 0 or 1. a2 is 0, 1, or 2. a3 is an integer that satisfies 0≦a3≦5+2(a2)−a4. a4 is 1, 2, or 3. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 11 represents a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. A 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 - may be replaced by -O-.

2. 2. The chemically amplified positive resist composition according to claim 1, wherein the sulfonium cation represented by formula (A2) is represented by the following formula (A1-2-1): 【Chemistry 4】 (In the formula, m4 to m10, m12 to m14, R F1 ~R F3 , R 2 ~R 5 , L A , L B and X L is the same as above.)

3. 3. The chemically amplified positive resist composition according to claim 2, wherein the sulfonium cation represented by formula (A1-2-1) is represented by the following formula (A1-2-2): 【Transformation 5】 (In the formula, m4 to m10, R F1 ~R F3 and R 2 ~R 5 is the same as above.)

4. 2. The chemically amplified positive resist composition according to claim 1, wherein the repeating unit represented by formula (B1) is represented by the following formula (A2-1): 【Transformation 6】 (In the formula, R A and a4 are the same as above.)

5. 2. The chemically amplified positive resist composition according to claim 1, wherein the polymer further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (A3-1) and a repeating unit represented by the following formula (A3-2): 【Transformation 7】 (In the formula, b1 is 0 or 1. b2 is 0, 1, or 2. b3 is an integer that satisfies 0≦b3≦5+2(b2)−b4. b4 is 1, 2, or 3. b5 is 0 or 1. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 12 represents a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 A part of - may be substituted with -O-. When b4 is 1, X is an acid labile group. When b4 is 2 or 3, X is each independently a hydrogen atom or an acid labile group, provided that at least one X is an acid labile group. c1 is 0, 1 or 2. c2 is 0, 1 or 2. c3 is 0, 1, 2, 3, 4 or 5. c4 is 0, 1 or 2. R 13 and R 14 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, and R 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 15 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms. R 16 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. A 3 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-A 31 - is. A 31 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, a phenylene group, or a naphthylene group, and the aliphatic hydrocarbylene group may contain at least one bond selected from a hydroxy group, an ether bond, an ester bond, and a lactone ring. * represents a bond to a carbon atom in the main chain.

6. 2. The chemically amplified positive resist composition according to claim 1, wherein the polymer further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (B3), a repeating unit represented by the following formula (B4), and a repeating unit represented by the following formula (B5): 【Transformation 8】 (In the formula, d is 0, 1, 2, 3, 4, 5, or 6. e is 0, 1, 2, 3, or 4. f1 is 0 or 1. f2 is 0, 1, or 2. f3 is 0, 1, 2, 3, 4, or 5. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 17 and R 18 are each independently a hydroxy group, a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 19 represents a halogen atom, a nitro group, a cyano group, a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, or a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, and when f2 is 1 or 2, it may also be a hydroxy group. A 4 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 - may be replaced by -O-.

7. 2. The chemically amplified positive resist composition according to claim 1, wherein the content of repeating units having an aromatic ring skeleton in all repeating units of the polymer contained in said base polymer (A) is 60 mol % or more.

8. 2. The chemically amplified positive resist composition according to claim 1, further comprising (B) a quencher.

9. 2. The chemically amplified positive resist composition according to claim 1, further comprising (C) an organic solvent.

10. Furthermore, (D) 2. The chemically amplified positive resist composition according to claim 1, comprising a fluorine atom-containing polymer containing at least one repeating unit 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): 【Chemistry 9】 (wherein h is 1, 2 or 3. R B are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 201 , R 202 , R 204 and R 205 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R 203 , R 206 , R 207 and R 208 are each independently a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group; R 203 , R 206 , R 207 and R 208 When is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bond. Z 1 is a (h+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (h+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms.

11. 11. The chemically amplified positive resist composition according to claim 10, wherein the fluorine atom-containing polymer further comprises at least one repeating unit 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): 【Chemistry 10】 (In the formula, x is 1, 2, or 3. y is an integer satisfying 0≦y≦5+2z−x. z is 0 or 1. R C are each independently a hydrogen atom or a methyl group. R 209 is a hydrogen atom or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a heteroatom-containing group interposed between its carbon-carbon bonds. R 210 is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a heteroatom-containing group interposed between its carbon-carbon bonds. R 211 is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and —CH 2 A portion of the - may be substituted with an ester bond or an ether bond. Z 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. Z 3 is a single bond, -O-, *-C(=O)-O-Z 31 -Z 32 - or *-C(=O)-NH-Z 31 -Z 32 - is. Z 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 is a single bond, an ester bond, an ether bond or a sulfonamide bond. * indicates a bond to a carbon atom in the main chain.)

12. 2. The chemically amplified positive resist composition according to claim 1, further comprising (E) an acid generator.

13. 13. A method for forming a resist pattern, comprising: a step of forming a resist film on a substrate using the chemically amplified positive resist composition according to any one of claims 1 to 12; a step of irradiating the resist film with a pattern using high-energy rays; and a step of developing the resist film irradiated with the pattern using an alkaline developer.

14. 14. The method for forming a resist pattern according to claim 13, wherein the high-energy radiation is KrF excimer laser light, ArF excimer laser light, extreme ultraviolet light, or an electron beam.

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

16. 14. The method for forming a resist pattern according to claim 13, wherein the substrate is a transmission or reflection mask blank.

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

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