Chemically amplified positive-type resist composition and resist pattern formation method

Abstract

The present invention provides a chemically amplified positive-type resist composition that exhibits excellent solvent solubility, high sensitivity, high contrast, and superior lithography performance such as resolution and LER, while also suppressing development defects in fine pattern formation and exhibiting excellent etching resistance, as well as a pattern formation method using the chemically amplified resist composition. [Solution] A chemically amplified positive-type resist composition comprising a photoacid generator consisting of a polymer having repeating units represented by formula (A1) and whose solubility in an alkaline aqueous solution increases by the action of an acid, and an onium salt of a specific structure containing an acid-unstable group. TIFF2026144369000427.tif5174

Description

[Technical Field]

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

[0002] In recent years, with the increasing integration of integrated circuits, there has been a demand for the formation of finer patterns, and chemically amplified resist compositions using acids as catalysts are primarily used for processing patterns of 0.2 μm or less. High-energy beams such as ultraviolet light, far ultraviolet light, and electron beams (EB) are used as exposure sources in this process, and EB lithography, in particular, which is used as an ultrafine processing technology, has become indispensable as a method for processing photomask blanks when creating photomasks for semiconductor manufacturing. As for the resist compositions used in such photolithography, there are positive types that form patterns by dissolving the exposed areas and negative types that form patterns by leaving the exposed areas intact, and the one that is easier to use is selected depending on the desired form of the resist pattern.

[0003] Generally, EB (electroluminescent) lithography does not use a mask. In the case of positive-type lithography, the area other than the region where the resist film is to be preserved is sequentially irradiated with a micro-area EB. In the case of negative-type lithography, the area where the resist film is to be preserved is sequentially irradiated. This process involves sweeping across the entire area of ​​the processed surface, which takes longer than batch exposure using a photomask. To maintain throughput, the resist film must be highly sensitive. Also, because the lithography time is long, differences tend to occur between the areas lithographed early and those lithographed later. Therefore, the temporal stability of the exposed area in a vacuum is an important performance requirement. Furthermore, in the processing of photomask blanks, which is a particularly important application, some photomask substrates have surface materials such as chromium oxide and other chromium compound films that can easily affect the pattern shape of the chemically amplified resist film. To maintain high resolution and the shape after etching, it is important to maintain a rectangular pattern profile of the resist film regardless of the substrate type.

[0004] The control of the sensitivity and pattern profile of the resist film mentioned above has been improved through various means, including the selection and combination of materials used in the resist composition and process conditions. One such improvement 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 depending on the time until post-exposure heating (PEB). A major cause of this time-dependent change is the diffusion of acid generated by exposure. This acid diffusion problem has been extensively studied not only in photomask processing but also in general resist compositions, as it significantly affects sensitivity and resolution.

[0005] Patent documents 1 and 2 describe examples of reducing roughness by increasing the bulk of the acid generated from an acid generator to suppress acid diffusion. However, such acid generators are still insufficient in suppressing acid diffusion, so there has been a need for the development of acid generators with even lower diffusion.

[0006] Furthermore, Patent Document 3 describes an example of controlling acid diffusion by bonding sulfonic acid generated by exposure to the resin used in the resist composition. This method of suppressing acid diffusion by introducing repeating units that generate acid upon exposure into the base polymer is effective in obtaining patterns with low line edge roughness (LER). However, depending on the structure and introduction rate of such repeating units, there have been cases where problems arose with the solubility of the base polymer containing the repeating units that generate acid upon exposure in organic solvents.

[0007] Incidentally, 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. However, because they exhibit significant absorption of light around 200 nm, they have not been used as materials for resist compositions for ArF lithography. Nevertheless, they are important materials for resist compositions for EB lithography and extreme ultraviolet (EUV) lithography, which are promising techniques for forming patterns smaller than the processing limit of ArF lithography, due to their high etching resistance.

[0008] For positive-type EB lithography resist compositions and EUV lithography resist compositions, the base polymers mainly used are those that, when irradiated with high-energy rays, use the acid generated from a photoacid generator as a catalyst to deprotect the acid-unstable groups (acid-degradable protecting groups) that mask the acidic functional groups of the phenol side chains of the base polymer, thereby making them solubilizable in an alkaline developer. Tertiary alkyl groups, tert-butoxycarbonyl groups, and acetal groups have been mainly used as the acid-unstable groups. While using protecting groups such as acetal groups, which require relatively low activation energy for deprotection, has the advantage of obtaining highly sensitive resist films, if the diffusion of the generated acid is not sufficiently suppressed, the deprotection reaction can occur even in unexposed areas of the resist film, leading to problems such as degradation of the LER and a decrease in the dimensional uniformity of the pattern line width (CDU).

[0009] Furthermore, when using a sulfonium salt that generates a high-acidity acid with a low pKa, such as the fluorinated alkanesulfonic acid described in Patent Document 4, and a polymer having repeating units with acetal groups, there was a problem in that a large LER pattern was formed. In other words, for the deprotection of acetal groups, which require a relatively low activation energy for deprotection, the acid strength of the fluorinated alkanesulfonic acid is too high, so even if acid diffusion is suppressed, the deprotection reaction proceeds due to trace amounts of acid diffused into the unexposed areas.

[0010] Furthermore, Patent Documents 5 and 6 propose photoacid generators that produce non-fluorinated aromatic sulfonic acids having multiple bulky alkyl substituents, and Patent Document 7 proposes a photoacid generator with a triarylbenzenesulfonic acid anion structure. Patent Document 8 proposes a photoacid generator that produces non-fluorinated aromatic sulfonic acids by introducing an iodine-containing aromatic ring. Patent Document 9 proposes a photoacid generator that produces aromatic sulfonic acids by introducing a tertiary ester-type acid-unstable group. Although the molecular weight of the generated acid is increased by multiple alkyl substituents, aromatic rings, and iodine atoms, thereby reducing acid diffusion, the suppression of acid diffusion is still insufficient when the purpose is to form fine patterns, and there is still room for further improvement.

[0011] With the recent progress in miniaturizing resist patterns, the formation of particularly fine isolated patterns has become important. To improve the dissolution contrast between exposed and unexposed areas, structural modifications are being made to the acid-unstable groups of the base polymer. Patent document 10 describes a structure in which the hydroxyl groups of polyhydroxystyrene are protected with a tertiary ether or acetal, and a fluorine atom is introduced at a position adjacent to these. Patent document 11 describes a structure in which the hydroxyl and carboxyl groups of vinyl salicylic acid are protected with a cyclic acetal. Both designs aim to increase the dissolution rate of the polymer after the deprotection reaction of the acid-unstable groups in the exposed area, and some improvement in performance has been confirmed. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent Publication No. 2009-053518 [Patent Document 2] Japanese Patent Publication No. 2010-100604 [Patent Document 3] Japanese Patent Publication No. 2011-22564 [Patent Document 4] Patent No. 5083528 [Patent Document 5] Patent No. 6248882 [Patent Document 6] Patent No. 7067271 [Patent Document 7] Patent No. 7032549 [Patent Document 8] Japanese Patent Publication No. 2023-177038 [Patent Document 9] Patent No. 7531671 [Patent Document 10] Japanese Patent Publication No. 2025-000201 [Patent Document 11] International Publication No. 2023 / 162837 [Overview of the project] [Problems that the invention aims to solve]

[0013] In recent years, there has been a demand for resist compositions that excel not only in line-and-space (LS), isoline (IL), and isospace (IS) patterns, but also in hole pattern shape. While the acid generator described in Patent Document 5, which generates a bulky acid and suppresses acid diffusion, produced patterns with good resolution and roughness, it had the problem of corner rounding occurring in hole patterns.

[0014] The present invention has been made in view of the above circumstances, and aims to provide a chemically amplified positive resist composition that exhibits excellent solvent solubility, high sensitivity, high contrast, and excellent lithography performance such as resolution and LER, particularly in photolithography using high-energy beams such as KrF excimer laser light, ArF excimer laser light, electron beam (EB), and EUV, and also suppresses development defects in fine pattern formation and exhibits excellent etching resistance, as well as a pattern formation method using the chemically amplified resist composition. [Means for solving the problem]

[0015] The present inventors, after diligent research to achieve the above objective, have developed a polymer containing repeating units having a cyclic acetal structure fused to an aromatic ring, and a photoacid generator that generates an arene sulfonic acid derivative, and -SO3 - It has two, three, or four aryl groups having an ether-type acid-unstable group on the aromatic ring to which it is bonded, and at least one of the aryl groups having an ether-type acid-unstable group is -SO3 - We discovered that when an onium salt having a structure bonded to a carbon atom adjacent to the carbon atom to which it is bonded is introduced into a resist composition as a photoacid generator, the acid generated has an appropriate acidity and excessive diffusion of the acid is suppressed, resulting in a resist pattern with good resolution, low LER, and suppressed development defects. Furthermore, due to its appropriate dissolution inhibition, a good rectangular resist pattern can be obtained, leading to the present invention.

[0016] In other words, the present invention provides the following chemically amplified positive-type resist composition and resist pattern formation method. 1. (A) A base polymer containing repeating units represented by the following formula (A1), wherein the polymer's solubility in alkaline aqueous solutions increases upon the action of an acid, and (B) Photoacid generator consisting of an onium salt represented by the following formula (B) A chemically amplified positive-type resist composition containing the following: [ka] (In the formula, a1 is either 0 or 1. When a1 is 0, a2 is 0, 1, 2, or 3, and when a1 is 1, a2 is 0, 1, 2, 3, 4, or 5.) R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 The bonds are single bonds, *-C(=O)-O-, or *-C(=O)-N(H)-. The asterisk (*) represents a bond with a carbon atom in the main chain. X 2 This refers to a single bond, an aliphatic hydrocarbylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining these. X3 and X 4 are each independently an oxygen atom or a sulfur atom, provided that X 2 and X 4 are bonded to adjacent carbon atoms of the aromatic ring. R 1 and R 2 are each independently a hydrogen atom, or a hydrocarbyl group having 1 to 20 carbon atoms which may optionally contain a heteroatom. Further, R 1 and R 2 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. R 3 is a halogen atom, a hydroxy group, a cyano group, a nitro group, a pentafluorosulfanyl group, a hydrocarbyl group having 1 to 20 carbon atoms which may optionally contain a heteroatom, a hydrocarbyloxy group having 1 to 20 carbon atoms which may optionally contain a heteroatom, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms which may optionally contain a heteroatom, a hydrocarbylthio group having 1 to 20 carbon atoms which may optionally contain a heteroatom, or -N(R 3A )(R 3B ). R 3A and R 3B are each independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. When a2 is 2 or more, each R 3 may be the same as or different from each other, and a plurality of R 3 may be bonded to each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded.)

Chemical Formula

Chemical Formula

[0017] A chemically amplified positive resist composition containing an onium salt represented by formula (B) as a photoacid generator can provide extremely high resolution, low LER, and suppressed development defects in microfabrication techniques, particularly EB lithography and EUV lithography. Furthermore, the onium salt represented by formula (B) is suitable as a material for chemically amplified positive resist compositions because it can provide good rectangular patterns due to its moderate dissolution inhibitory properties. [Modes for carrying out the invention]

[0018] The present invention will be described in detail below. In the following description, depending on the structure represented by the chemical formula, an asymmetric carbon may be present, and enantiomers or diastereomers may exist. In such cases, one formula will represent all of these isomers. These isomers may be used individually or as a mixture of two or more.

[0019] [Chemically amplified positive-type resist composition] [(A) Base polymer] The chemically amplified positive resist composition of the present invention includes a base polymer as component (A) which contains a polymer whose solubility in an alkaline developer increases with the action of an acid.

[0020] The polymer contains repeating units represented by the following formula (A1) (hereinafter also referred to as repeating unit A1). [ka]

[0021] In formula (A1), a1 is either 0 or 1. When a1 is 0, it is a benzene ring, and when a1 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, a1 being a benzene ring (0) is preferred. When a1 is 0, a2 is 0, 1, 2, or 3, and when a1 is 1, it is 0, 1, 2, 3, 4, or 5. From the viewpoint of raw material procurement, a2 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0022] In formula (A1), R A represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R A is preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom.

[0023] In formula (A1), X 1 represents a single bond, *-C(=O)-O- or *-C(=O)-N(H)-. * represents a bonding site to a carbon atom in the main chain. Among these, a single bond or *-C(=O)-O- is preferable, and a single bond is more preferable.

[0024] In formula (A1), X 2 represents a single bond, an aliphatic hydrocarbylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining these groups. Among these, from the viewpoint of raw material procurement, a single bond, a carbonyl group or a sulfonyl group is preferable, and from the viewpoint of the polar group generated after the reaction, a single bond or a carbonyl group is more preferable.

[0025] In formula (A1), X 3 and X 4 are each independently an oxygen atom or a sulfur atom. Provided that X 2 and X 4 are bonded to adjacent carbon atoms of an aromatic ring. X 3 and X 4 may be the same as or different from each other, but from the viewpoint of reactivity, it is preferable that both X 3 and X 4 are oxygen atoms.

[0026] In formula (A1), R 1 and R 2Each of these is a C1-C20 hydrocarbyl group which may independently contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups 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 eicosyl; cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, and 4-methylcyclo Examples include cyclic saturated hydrocarbyl groups with 3 to 20 carbon atoms, such as hexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; alkenyl groups with 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl groups; cyclic unsaturated hydrocarbyl groups with 3 to 20 carbon atoms, such as cyclohexenyl groups; aryl groups with 6 to 20 carbon atoms, such as phenyl and naphthyl groups; aralkyl groups with 7 to 20 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- groups of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, the material may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0027] Also, R 1 and R 2These may bond with each other to form a ring 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, an adamantane ring, and so on. 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 -CH2- in the ring may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, the ring may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and so on.

[0028] In formula (A1), R 3 This may include halogen atoms, hydroxyl groups, cyano groups, nitro groups, pentafluorosulfanyl groups, C1-C20 hydrocarbyl groups which may contain heteroatoms, C1-C20 hydrocarbyloxy groups which may contain heteroatoms, C2-C20 hydrocarbyloxycarbonyl groups which may contain heteroatoms, C1-C20 hydrocarbylthio groups which may contain heteroatoms, or -N(R 3A )(R 3B ) is R 3A and R 3B Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. 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 portion of the hydrocarbyl group and the hydrocarbyloxy group, hydrocarbyloxycarbonyl group and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 12 and R 13Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, and nitrogen atoms, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. When a2 is 2 or more, each R 3 They may be the same as or different from each other.

[0029] Also, when a2 is 2 or more, multiple R 3 However, they may bond with each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. Specific examples of the ring formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornane rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., and as a result, the ring may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0030] Specific examples of repeating unit A1 are shown below, but are not limited to these. Note that in the following formula, R A The same as described above, where Me is a methyl group. Furthermore, the bonding positions of the various substituents on the aromatic ring may be interchanged. [ka]

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[0080] In the chemically amplified resist composition of the present invention, a structural feature of the (A) base polymer is that it contains repeating units A1 having a cyclic acetal structure fused to an aromatic ring. The cyclic acetal structure fused to an aromatic ring has good solvent solubility and also acts as an acid-unstable group, so a deprotection reaction proceeds upon the action of acid, generating two polar groups. This improves the contrast between the exposed and unexposed areas. Furthermore, since the two polar groups generated are bonded to adjacent carbon atoms, the hydroxyl group or carboxyl group forms hydrogen bonds with each other. This suppresses swelling caused by the alkaline developer during alkaline development and prevents deformation of the resist pattern in the unexposed areas. The cyclic acetal structure fused to an aromatic ring remaining in the unexposed areas becomes a bicyclocyclic ring structure, thus exhibiting high resistance in the etching process. Before exposure, the polymer exhibits high solvent solubility due to the cyclic acetal structure contained in repeating unit A1, thus suppressing precipitation in the solvent. Furthermore, when developing with an alkaline developer after exposure, the polar groups generated after deprotection of the acetal structure have high affinity for the alkaline developer, effectively removing the exposed areas and reducing the risk of development defects.

[0081] The content of repeating unit A1 in the total repeating units of the polymer is preferably 5 to 50 mol%, more preferably 10 to 45 mol%, and even more preferably 15 to 40 mol%. Repeating unit A1 may be used alone or in combination of two or more types.

[0082] The polymer may further contain repeating units represented by the following formula (A2) (hereinafter also referred to as repeating unit A2). [ka]

[0083] In formula (A2), b1 is 0, 1, or 2, where b1 is a benzene skeleton when 0, a naphthalene skeleton when 1, and an anthracene skeleton when 2. b2 is 1, 2, or 3. b3 is an integer satisfying 0 ≤ b3 ≤ 5 + 2(b1) - b2. When b1 is 0, preferably b2 is 0, 1, 2, or 3 and b3 is 1, 2, or 3. When b1 is 1 or 2, preferably b2 is 0, 1, 2, 3, or 4 and b3 is 1, 2, or 3.

[0084] In formula (A2), R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0085] In formula (A2), Y 1 The bonds are single bonds, *-C(=O)-O-, or *-C(=O)-N(H)-. The asterisk (*) represents a bond with a carbon atom in the main chain.

[0086] In formula (A2), R 11 This is a halogen atom, a nitro group, a carboxyl group, a saturated hydrocarbyl group having 1 to 6 carbon atoms that may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms that may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms that may be substituted with a halogen atom. The saturated hydrocarbyl group, and the saturated hydrocarbyl portion 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 their structural isomers; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining these. If the number of carbon atoms is below the upper limit, the solubility in alkaline developer is good. When b3 is 2 or more, each R 11 They may be the same as or different from each other.

[0087] In formula (A2), A 1This 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-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples include alkanediyl groups having 1 to 10 carbon atoms such as methylene group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, and structural isomers thereof; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, and cyclohexanediyl group; and groups obtained by combining these. If the saturated hydrocarbylene group contains an ether bond, Y in formula (A2) 1 When is *-C(=O)-O- or *-C(=O)-N(H)-, it can be placed in any position other than between the α-position carbon atom and the β-position carbon atom relative to -O- or -N(H)-. Also, Y 1 When there is a single bond, the atom bonded to the main chain becomes an etheric oxygen atom, and the second ether bond may be inserted at any position other than between the α-carbon and β-carbon atoms relative to the etheric oxygen atom. Furthermore, it is preferable that the number of carbon atoms in the saturated hydrocarbylene group is 10 or less, as this allows for sufficient solubility in alkaline developing solutions.

[0088] Y 1 and A 1 When both are single bonds, that is, when the aromatic ring is directly bonded to the polymer's main chain (i.e., the linker (-Y), 1 -A 1 If (-) is not present, preferred examples of repeating unit A2 include units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, etc. Specifically, these include, but are not limited to, the following. Note that in the following formula, R A This is the same as described above. [ka]

[0089] [ka]

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[0091] Y 1 is *-C(=O)-O- or *-C(=O)-N(H)- (i.e., Y as a linker) 1 -A 1 When (having -), preferred examples of repeating unit A2 are, but are not limited to, those listed below. Note that in the following formula, R A This is the same as described above. [ka]

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[0096] If the polymer contains repeating unit A2, its content is preferably 30 to 95 mol%, and more preferably 35 to 85 mol%, of the total repeating units constituting the polymer. However, if the polymer contains at least one of the repeating units represented by formula (A3), formula (A4), and formula (A5) that provide high etching resistance, and the unit has a phenolic hydroxyl group as a substituent, it is preferable to include the ratio of the repeating unit in the above range. Repeating unit A2 may be used alone or in combination of two or more types.

[0097] The polymer may contain at least one selected from the following repeating units: a repeating unit represented by formula (A3) (hereinafter also referred to as repeating unit A3), a repeating unit represented by formula (A4) (hereinafter also referred to as repeating unit A4), and a repeating unit represented by formula (A5) (hereinafter also referred to as repeating unit A5). [ka]

[0098] In equations (A3) and (A4), c is 0, 1, 2, 3, 4, 5, or 6. d is 0, 1, 2, 3, or 4.

[0099] In formulas (A3) and (A4), R 21 and R 22 Each of these is independently a hydroxyl group, a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms that may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms that may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms that 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 c is 2, 3, 4, 5, or 6, each R 21 They may be the same or different from each other. When d is 2, 3 or 4, each R 22They may be the same as or different from each other.

[0100] In formula (A5), e1 is 0 or 1. e2 is 0, 1 or 2. When e2 is 0, it is a benzene skeleton; when it is 1, it is a naphthalene skeleton; and when it is 2, it is an anthracene skeleton. e3 is 0, 1, 2, 3, 4 or 5. When e2 is 0, e3 is preferably 0, 1, 2 or 3, and when e2 is 1 or 2, e3 is preferably 0, 1, 2, 3 or 4.

[0101] In formula (A5), R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0102] In formula (A5), R 23 The saturated hydrocarbyl group is 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, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, or a cyano group, and when e3 is 1 or 2, it may also be a hydroxyl 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 e3 is 2, 3, 4, or 5, each R 33 They may be the same as or different from each other.

[0103] In formula (A5), A 2 A 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-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and a specific example thereof is A in formula (A2). 1 Examples similar to those given in the explanation can be cited.

[0104] When at least one of the repeating units A3 to A5 is used as a constituent unit of the polymer, the etching resistance of the aromatic ring, plus the addition of a ring structure to the main chain, is enhanced, resulting in improved etching resistance and resistance to EB irradiation during pattern inspection.

[0105] If the polymer contains repeating units A3 to A5, the content of repeating units A3 to A5 is preferably 5 mol% or more of the total repeating units of the polymer in order to obtain the effect of improving etching resistance. Furthermore, the content of repeating units A3 to A5 is preferably 25 mol% or less, and more preferably 20 mol% or less, of the total repeating units constituting the polymer. If the repeating units do not have a functional group, or if the functional group is something other than a hydroxyl group, an introduction amount of 25 mol% or less is preferable because there is no risk of development defects occurring. Repeating units A3 to A5 may be used individually or in combination of two or more types.

[0106] The polymer preferably contains at least one repeating unit selected from repeating units A1, A2, and A3 to A5, as this is advantageous in achieving both high etching resistance and resolution. In this case, it is preferable that these repeating units make up 60 mol% or more of the total repeating units of the polymer, more preferably 70 mol% or more, even more preferably 80 mol% or more, and even more preferably 90 mol% or more.

[0107] The polymer may further include at least one repeating unit selected from the repeating units represented by the following formula (A6-1) and the repeating unit represented by the following formula (A6-2). [ka]

[0108] In formula (A6-1), f1 is 0 or 1. f2 is 0, 1 or 2, where 0 is a benzene skeleton, 1 is naphthalene, and 2 is anthracene. f3 is an integer satisfying 0 ≤ f3 ≤ 5 + 2(f2) - f4. f4 is 1, 2 or 3. f5 is 0 or 1. When f2 is 0, preferably f3 is 0, 1, 2 or 3 and f4 is 1, 2 or 3, and when f2 is 1 or 2, preferably f3 is 0, 1, 2, 3 or 4 and f4 is 1, 2 or 3.

[0109] In equation (A6-2), f11 is 0, 1, or 2. f12 is 0, 1, or 2. f13 is 0, 1, or 2. f14 is 0, 1, 2, 3, 4, or 5.

[0110] In equations (A6-1) and (A6-2), R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0111] In formula (A6-1), A 3The saturated hydrocarbylene group is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and some of the -CH2- atoms of the saturated hydrocarbylene group may be substituted with -O- atoms. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples include alkanediyl groups having 1 to 10 carbon atoms such as methylene groups, ethane-1,2-diyl groups, propane-1,3-diyl groups, butane-1,4-diyl groups, pentane-1,5-diyl groups, hexane-1,6-diyl groups, and structural isomers thereof; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms such as cyclopropanediyl groups, cyclobutanediyl groups, cyclopentanediyl groups, and cyclohexanediyl groups; and groups obtained by combining these. If the saturated hydrocarbylene group contains an ether bond, when f1 in formula (A6-1) is 1, the ether bond may be located at any position other than between the α-carbon and β-carbon atoms relative to the esterifying oxygen atom. When f1 is 0, the atom bonded to the main chain becomes an etheric oxygen atom, and the second ether bond may be located at any position other than between the α-carbon and β-carbon atoms relative to the etheric oxygen atom. It is preferable that the saturated hydrocarbylene group has 10 or fewer carbon atoms, as this allows for sufficient solubility in alkaline developing solutions.

[0112] In formula (A6-2), A 4 This refers to a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OA 41 - is A 41 This is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, which may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring, or a phenylene group or naphthylene group. * indicates a bond with a carbon atom of the main chain.

[0113] In formula (A6-1), R 31This is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms that may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms that may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms that may be substituted with a halogen atom. The saturated hydrocarbyl group, and the saturated hydrocarbyl portion of the saturated hydrocarbyloxy group and saturated hydrocarbylcarbonyloxy group, may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, hexyl, and their structural isomers; cycloalkyl groups having 3 to 6 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining these. If the number of carbon atoms is below the upper limit, solubility in alkaline developer is good. When f3 is 2 or more, each R 31 They may be the same as or different from each other.

[0114] In formula (A6-2), R 32 and R 33 Each of these is independently a hydrocarbyl group having 1 to 10 carbon atoms, which may contain heteroatoms, and R 32 and R 33 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded.

[0115] In formula (A6-2), R 34 Each of these is 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. When f13 is 2, each R 34 They may be the same as or different from each other.

[0116] In formula (A6-2), R 35 Each of these is independently a hydrocarbyl group having 1 to 10 carbon atoms, which may contain heteroatoms. When f14 is 2, 3, 4, or 5, each R 35 They may be the same as or different from each other.

[0117] In formula (A6-1), when f4 is 1, X is an acid-unstable group. When f4 is 2 or 3, X is independently either a hydrogen atom or an acid-unstable group, but at least one is an acid-unstable group. That is, the repeating unit A6-1 is a configuration in which at least one phenolic hydroxyl group attached to an aromatic ring is protected by an acid-unstable group, or a carboxyl group attached to an aromatic ring is protected by an acid-unstable group. The acid-unstable group can be any that is removed by acid to yield an acidic group, as has been used in many known chemically amplified positive resist compositions, and is not particularly limited.

[0118] Examples of the acid-unstable group include tertiary saturated hydrocarbyl groups. The tertiary saturated hydrocarbyl group is preferably one having 4 to 18 carbon atoms, as the monomer for polymerization is obtained by distillation.

[0119] The saturated hydrocarbyl group bonded to the tertiary carbon atom of the tertiary saturated hydrocarbyl group is preferably one having 1 to 15 carbon atoms. The saturated hydrocarbyl group having 1 to 15 carbon atoms may be linear, branched, or cyclic, and may contain oxygen atom-containing functional groups such as ether bonds or carbonyl groups between its carbon-carbon bonds. Furthermore, saturated hydrocarbyl groups bonded to tertiary carbon atoms may bond to each other, forming a ring together with the tertiary carbon atom to which they are bonded.

[0120] Specific examples of groups bonded to the tertiary carbon atom include methyl group, ethyl group, propyl group, adamantyl group, norbornyl group, tetrahydrofuran-2-yl group, 7-oxanorbornan-2-yl group, cyclopentyl group, 2-tetrahydrofuryl group, 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 7,10Examples include a dodecyl group and a 3-oxo-1-cyclohexyl group.

[0121] The tertiary saturated hydrocarbyl groups include tert-butyl group, tert-pentyl group, 1-ethyl-1-methylpropyl group, 1,1-diethylpropyl group, 1,1,2-trimethylpropyl group, 1-adamantyl-1-methylethyl group, 1-methyl-1-(2-norbornyl)ethyl group, 1-methyl-1-(tetrahydrofuran-2-yl)ethyl group, 1-methyl-1-(7-oxanorbornan-2-yl)ethyl group, 1-methylcyclopentyl group, 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-norbonyl group, 2-Ethyl-2-norbonyl 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 Examples include, but are not limited to, the 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.

[0122] Furthermore, the group represented by the following formula (A6-1-1) can be cited as the acid-unstable group. The group represented by formula (A6-1-1) is commonly used as an acid-unstable group and is a useful choice as an acid-unstable group that stably gives patterns where the interface between the pattern and the substrate is relatively rectangular. When X is the group represented by formula (A6-1-1), an acetal structure is formed. [ka] (In the equation, dashed lines represent connections.)

[0123] In formula (A6-1-1), R L11 This 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.

[0124] R L11 The group is appropriately selected according to the design of the sensitivity of the decomposition group to acid. For example, if the design is to decompose with a strong acid while ensuring relatively high stability, a group in which the carbon atom bonded to the hydrogen atom or acetal carbon is a tertiary carbon atom is preferred. L11 Examples include, but are not limited to, tert-butyl, tert-pentyl, and 1-adamantyl groups. Linear alkyl groups are preferred when designing for high sensitivity to pH changes using relatively high reactivity. The combination with acid generators and quenchers incorporated into the resist composition also matters, but R L12 If a relatively large saturated hydrocarbyl group is selected at the terminal and the change in solubility due to decomposition is designed to be significant, then R L11 Preferably, the carbon atom bonded to the acetal carbon is a secondary carbon atom. L11 Examples include, but are not limited to, isopropyl groups, sec-butyl groups, cyclopentyl groups, and cyclohexyl groups.

[0125] In formula (A6-1-1), R L12This is a hydrocarbyl group having 1 to 30 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, linear, branched, or cyclic, and some of the -CH2- atoms of the hydrocarbyl group may be substituted with heteroatoms such as oxygen or sulfur atoms, resulting in the inclusion of ether bonds, sulfide bonds, etc. 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, to obtain higher resolution in fine pattern formation, R L12 It is preferably a hydrocarbyl group having 1 to 6 carbon atoms. L12 When the group is a hydrocarbyl group with 1 to 6 carbon atoms, the alcohol produced after the deprotection reaction with acid is water-soluble. Therefore, it dissolves in the developer when forming a positive pattern with an alkaline developer, thus suppressing residual defects in the exposed areas.

[0126] Preferred examples of the group represented by formula (A6-1-1) are, but are not limited to, those listed below. Note that in the following formula, R L11 The same as above, and the dashed lines represent connections. [ka]

[0127] [ka]

[0128] [ka]

[0129] Preferred examples of repeating unit A6-2 are, but are not limited to, those shown below. Note that in the following formula, R A This is the same as described above. [ka]

[0130] [ka]

[0131] Other acid-unstable groups can also be used in which the hydrogen atom of a phenolic hydroxyl group is substituted with -CH2COO- (tertiary saturated hydrocarbyl group). In this case, the same tertiary saturated hydrocarbyl group used for protecting the phenolic hydroxyl group as described above can be used.

[0132] If the polymer contains at least one selected from repeating units A6-1 and A6-2, the content is preferably 5 to 30 mol% of the total repeating units of the polymer, and when repeating units A1, A3-1, and A3-2 are combined, the content is preferably 10 to 60 mol%, more preferably 10 to 50 mol%, and even more preferably 10 to 40 mol% of the total repeating units of the polymer. Repeating units A6-1 and A6-2 may be used individually or in combination of two or more.

[0133] The polymer may contain at least one selected from the following repeating units: a repeating unit represented by formula (A7) (hereinafter also referred to as repeating unit A7), a repeating unit represented by formula (A8) (hereinafter also referred to as repeating unit A8), a repeating unit represented by formula (A9) (hereinafter also referred to as repeating unit A9), a repeating unit represented by formula (A10) (hereinafter also referred to as repeating unit A10), and a repeating unit represented by formula (A11) (hereinafter also referred to as repeating unit A11). [ka]

[0134] In formulas (A7) to (A11), R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 1 Z is a phenylene group which may have a single bond or a substituent. 2This is a single bond, **-C(=O)-OZ 21 -,**-C(=O)-N(H) -Z 21 - or **-OZ 21 - is Z 21 This is a divalent group obtained by combining an aliphatic hydrocarbylene group, a phenylene group, or a combination thereof, having 1 to 6 carbon atoms, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 3 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, amide bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. 4 This is a single bond, or a divalent group obtained by combining an aliphatic hydrocarbylene group, a phenylene group, or a combination thereof, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 5 These are, independently, a single bond, an optionally substituted phenylene group, an optionally substituted naphthylene group, and *-C(=O)-OZ 51 -or *-C(=O)-N(R)-Z 51 - is Z 51 R is a C1-C10 aliphatic hydrocarbylene group, phenylene group, or naphthylene group, and the aliphatic hydrocarbylene group may contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or a lactone ring. R is a C1-C10 hydrocarbyl group which may contain a hydrogen atom or a heteroatom. Z 6 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, amide bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. 7 Each of these is independently a single bond, ***-Z 71 -C(=O)-O-, ***-C(=O)-N(R)-Z 71 -or ***-OZ 71 - is. is. Z 71 R is a hydroxylene group having 1 to 20 carbon atoms, which may contain heteroatoms. R is the same as described above. Z 8 These are, independently, single bonds, ****-Z81 -C(=O)-O-, ****-C(=O)-N(R)-Z 81 -or ****-OZ 81 - is Z 81 R is a hydroxylene group having 1 to 20 carbon atoms, which may contain heteroatoms. R is the same as described above. Z 9 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, trifluoromethyl groups, and *-C(=O)-OZ. 91 -, *-C(=O)-N(R)-Z 91 -or *-OZ 91 - is Z 91 R is a phenylene group substituted with an aliphatic hydrocarbylene group, phenylene group, fluorinated phenylene group, or trifluoromethyl group having 1 to 6 carbon atoms, and may contain a carbonyl group, ester bond, ether bond, or hydroxyl group. R is the same as above. * represents a bond with a carbon atom of the main chain. ** represents Z 1 This represents a combination with Z. *** represents Z 6 This represents a combination with Z. **** is Z 7 This represents a combination of two things.

[0135] Z 21 , Z 51 and Z 91 The aliphatic hydrocarbylene group represented by can be linear, branched, or cyclic, and specific examples include methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, propane-2,2-diyl group, butane-1,1-diyl group, butane-1,2-diyl group, butane-1,3-diyl group, butane- Examples include alkanediyl groups such as 2,3-diyl group, butane-1,4-diyl group, 1,1-dimethylethane-1,2-diyl group, pentane-1,5-diyl group, 2-methylbutane-1,2-diyl group, and hexane-1,6-diyl group; cycloalkanediyl groups such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, and cyclohexanediyl group; and groups obtained by combining these.

[0136] Z 71 and Z 81 The hydrocarbylene group, which may contain a heteroatom represented by , may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples are listed below, but are not limited to these. [ka] (In the equation, dashed lines represent connections.)

[0137] In formula (A7), R 41 and R 42Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups; C3-C20 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; C2-C20 alkenyl groups such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl groups; C3-C20 cyclic unsaturated hydrocarbyl groups such as cyclohexenyl; C6-C20 aryl groups such as phenyl, naphthyl, and thienyl groups; C7-C20 aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these, but aryl groups are preferred. 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, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0138] Also, R 41 and R 42 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. Specific examples of such a ring include those represented by the following formula. [ka] (In the formula, the dashed line represents Z 4 (This is a combination of the two.)

[0139] Specific examples of cations of repeating unit A7 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0140] [ka]

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] [ka]

[0149] In formula (A7), M - The first is a non-nucleophilic counterion. Preferred non-nucleophilic counterions include halide ions, sulfonate anions, imidate anions, and methidate anions. Specific examples of halide ions include chloride ions and bromide ions. Specific examples of sulfonate anions (sulfonate ions) include fluoroalkyl sulfonate ions such as triflate ions, 1,1,1-trifluoroethanesulfonate ions, and nonafluorobutanesulfonate ions; aryl sulfonate ions such as tosylate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, and 1,2,3,4,5-pentafluorobenzenesulfonate ions; and alkyl sulfonate ions such as mesylate ions and butanesulfonate ions. Specific examples of imidate anions (imide ions) include bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, and bis(perfluorobutylsulfonyl)imide ions. Specific examples of the methidate anion (methide ion) mentioned above include tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0150] Other examples of the aforementioned non-nucleophilic counterions include anions represented by any of the following formulas (A7-1) to (A7-4). [ka]

[0151] In formula (A7-1), R fa R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (A7-1-1) described later. fa1Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0152] The anion represented by formula (A7-1) is preferably the one represented by the following formula (A7-1-1). [ka]

[0153] In formula (A7-1-1), Q 1 and Q 2 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, but to improve solvent solubility, it is preferable that at least one of them is a trifluoromethyl group. m is 0, 1, 2, 3, or 4, but it is particularly preferable that it is 1. R fa1 This is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. The heteroatoms are preferably oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc., with oxygen atoms being more preferred. From the viewpoint of obtaining high resolution in fine pattern formation, the hydrocarbyl group having 6 to 30 carbon atoms is particularly preferred.

[0154] In formula (A7-1-1), R fa1The C1-C40 hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C40 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and eicosyl; cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl. Examples include cyclic saturated hydrocarbyl groups with 3 to 40 carbon atoms, such as the tyl group; unsaturated aliphatic hydrocarbyl groups with 2 to 40 carbon atoms, such as the 2-propenyl group and the 3-cyclohexenyl group; aryl groups with 6 to 40 carbon atoms, such as the phenyl group, the 1-naphthyl group, the 2-naphthyl group, and the 9-fluorenyl group; aralkyl groups with 7 to 40 carbon atoms, such as the benzyl group and the diphenylmethyl group; aromatic ring-containing polycyclic hydrocarbyl groups with 7 to 40 carbon atoms, such as the 9,10-ethano-9,10-dihydroanthryl group and the 6,13-ethano-6,13-dihydropentacenyl group; hydrocarbyl groups with 17 to 40 carbon atoms having a steroid skeleton; and groups obtained by combining these.

[0155] 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, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Specific examples of hydrocarbyl groups containing heteroatoms include tetrahydrofuryl group, methoxymethyl group, ethoxymethyl group, methylthiomethyl group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy)methyl group, acetoxymethyl group, 2-carboxy-1-cyclohexyl group, 2-oxopropyl group, 4-oxo-1-adamantyl group, and 3-oxocyclohexyl group.

[0156] In formula (A7-1-1), L a1 The bond can be a single bond, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, or a carbamate bond, but from a synthetic viewpoint, an ether bond or an ester bond is preferred, and an ester bond is even more preferred.

[0157] Specific examples of anions represented by formula (A7-1) are listed below, but are not limited to these. Note that in the formula below, Q 1 This is the same as above, and Ac is an acetyl group. [ka]

[0158] [ka]

[0159] [ka]

[0160] [ka]

[0161] [ka]

[0162] [ka]

[0163] [ka]

[0164] [ka]

[0165] [ka]

[0166] [ka]

[0167] [ka]

[0168] [ka]

[0169] In formula (A7-2), R fb1 and R fb2Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (A7-1-1). fa1 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fb1 and R fb2 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 However, they bond to each other and the group to which they bond (-CF2-SO2-N - It may form a ring with -SO2-CF2-), in which case R fb1 and R fb2 The groups obtained by the bonding of these groups are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0170] In formula (A7-3), R fc1 , R fc2 and R fc3 Each of these is a hydrocarbyl group having 1 to 40 carbon atoms, which may each contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (A7-1-1). fa1 Examples of hydrocarbyl groups represented by R include those similar to those exemplified. fc1 , R fc2 and R fc3 Preferably, R is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 However, they bond to each other and the group to which they bond (-CF2-SO2-C - It may form a ring with -SO2-CF2-), in which case R fc1 and R fc2 The groups obtained by the bonding of these groups are preferably fluorinated ethylene groups or fluorinated propylene groups.

[0171] In formula (A7-4), R fdR is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R in formula (A7-1-1). fa1 Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0172] Specific examples of anions represented by formula (A7-4) are listed below, but are not limited to these. [ka]

[0173] [ka]

[0174] Further examples of the aforementioned non-nucleophilic counterions include anions having an aromatic ring substituted with an iodine or bromine atom. A specific example of such anion is represented by the following formula (A7-5). [ka]

[0175] In equation (A7-5), x is 1, 2, or 3. y is 1, 2, 3, 4, or 5. z is 0, 1, 2, or 3, where 1 ≤ y + z ≤ 5. y is preferably 1, 2, or 3, more preferably 2 or 3. z is preferably 0, 1, or 2.

[0176] In formula (A7-5), X BI is an iodine atom or a bromine atom. When x and / or y are 2 or more, each X BI They may be the same as or different from each other.

[0177] In formula (A7-5), L 11 This is a single bond, ether bond, ester bond, sulfonic acid ester bond, carbonate bond, carbamate bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms, and a portion of the -CH2- of the hydrocarbylene group may be substituted with an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched, or cyclic.

[0178] In formula (A7-5), L 12 When x is 1, it is a C1-C20 hydrocarbylene group which may contain a single bond or a heteroatom, and when x is 2 or 3, it is a C1-C20 (x+1) valent hydrocarbon group which may contain a heteroatom.

[0179] L 12 The C1-C20 hydrocarbylene group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C20 alkanediyl groups such as methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl; cyclopentanediyl, cyclohexanediyl, norbornanediyl, adamantanediyl, tricyclo[5.2.1.0 2,6Examples include cyclic saturated hydrocarbylene groups with 3 to 20 carbon atoms, such as decanediyl groups; unsaturated aliphatic hydrocarbylene groups with 2 to 20 carbon atoms, such as vinylene groups and propene-1,3-diyl groups; arylene groups with 6 to 20 carbon atoms, such as phenylene groups, naphthylene groups, and anthracenediyl groups; aromatic ring-containing polycyclic hydrocarbylene groups with 7 to 20 carbon atoms, such as 9,10-ethano-9,10-dihydroanthracenediyl groups and 6,13-ethano-6,13-dihydropentacene groups; and groups obtained by combining these. 12 The (x+1) valent hydrocarbon group having 1 to 20 carbon atoms, represented by , may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include groups obtained by removing one or two hydrogen atoms from the aforementioned specific examples of the 1 to 20 carbon atom hydrocarbylene group.

[0180] Furthermore, some or all of the hydrogen atoms of the hydrocarbylene group and the (x+1) valent hydrocarbon 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- of the hydrocarbylene group and the (x+1) valent hydrocarbon group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, the material may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0181] In formula (c1-5), L 13 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, or carbamate bonds.

[0182] In formula (A7-5), R feThis includes hydroxyl groups, carboxyl groups, fluorine atoms, chlorine atoms, bromine atoms, amino groups, C1-C20 hydrocarbyl groups, C1-C20 hydrocarbyloxy groups, C1-C20 hydrocarbylthio groups, C2-C20 hydrocarbylcarbonyl groups, C2-C20 hydrocarbyloxycarbonyl groups, C2-C20 hydrocarbylcarbonyloxy groups, or C1-C20 hydrocarbylsulfonyloxy groups, -N(R feA )(R feB ), -N(R feC )-C(=O)-R feD or -N(R feC )-C(=O)-OR feD The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylthio group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may contain at least one selected from fluorine, chlorine, bromine, iodine, hydroxyl, amino, ester, and ether bonds. feA and R feB Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. feC R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may also contain a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. feDThis is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When x and / or z is 2 or more, each R fe They may be the same as or different from each other.

[0183] Of these, R fe Examples include hydroxyl groups, -N(R feC )-C(=O)-R feD , -N(R feC )-C(=O)-OR feD Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc. are preferred.

[0184] In formula (A7-5), Rf 11 ~Rf 14 Each of these is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of these is either a fluorine atom or a trifluoromethyl group. Also, Rf 11 and Rf 12 These may combine to form a carbonyl group. In particular, Rf 13 and Rf 14 It is preferable that both are fluorine atoms.

[0185] Specific examples of anions represented by formula (A7-5) are listed below, but are not limited to these. Note that in the formula below, X BI This is the same as described above. [ka]

[0186]

change

[0187]

change

[0188]

change

[0189]

change

[0190]

change

[0191]

change

[0192]

change

[0193]

change

[0194]

change

[0195]

change

[0196]

change

[0197]

change

[0198]

change

[0199]

change

[0200]

change

[0201]

change

[0202]

change

[0203]

change

[0204]

change

[0205]

change

[0206]

change

[0207]

change

[0208]

change

[0209] M -Other examples of anions represented by include paragraphs

[0076] and

[0106] of International Publication No. 2023 / 157455, paragraph

[0111] of International Publication No. 2024 / 24801, paragraphs

[0253] to

[0256] of International Publication No. 2024 / 43121, paragraphs

[0044] to

[0045] of International Publication No. 2024 / 57751, paragraphs

[0205] to

[0220] of International Publication No. 2024 / 122423, paragraphs

[0170] to

[0178] of Japanese Patent Publication No. 2023-123183, and paragraphs

[0026] to

[0028] of Japanese Patent Publication No. 2024-62406. Paragraphs

[0022] to

[0025] of JP 2024-62407, paragraphs

[0026] to

[0028] of JP 2024-62408, paragraphs

[0028] to

[0030] of JP 2024-68156, paragraphs

[0026] to

[0028] of JP 2024-68157, paragraphs

[0028] to

[0030] of JP 2024-68158, paragraphs

[0028] to

[0030] of JP 2024-68159, paragraphs

[0031] to

[0033] of JP 2024-72280, paragraph

[0023] of JP 2024-72281 Paragraphs

[0026] to

[0029] of JP 2024-77618, paragraphs

[0020] to

[0021] of JP 2024-77619, paragraphs

[0140] to

[0143] of JP 2024-80672, paragraphs

[0023] to

[0025] of JP 2024-83303, paragraphs

[0028] to

[0031] of JP 2024-83304, paragraphs

[0030] to

[0033] of JP 2024-99500, paragraphs

[0028] to

[0030] of JP 2024-99502, and JP 2024-101557 Paragraphs

[0030] to

[0032] of the publication, paragraphs

[0025] to

[0027] of JP 2024-102842 A, paragraphs

[0033] to

[0035] of JP 2024-102843 A, paragraphs

[0021] to

[0022] of JP 2024-127832 A, paragraphs

[0169] to

[0172] of JP 2024-144354 A, paragraphs

[0178] to

[0181] of JP 2024-144356 A, paragraphs

[0040] to

[0143] of JP 2024-160436 A, paragraphs

[0157] to

[0158] of Patent No. 7247732,Examples include those described in paragraphs

[0227] to

[0238] of Japanese Patent Publication No. 7446352, paragraphs

[0253] to

[0256] of Japanese Patent Publication No. 7466597, and paragraphs

[0309] to

[0312] of Japanese Patent Publication No. 7466782.

[0210] As the non-nucleophilic counterions, the following can also be used: a fluorobenzenesulfonic acid anion bonded to an aromatic group containing an iodine atom, as described in Japanese Patent No. 6648726; an anion having a mechanism for decomposition by acid, as described in International Publication No. 2021 / 200056 and Japanese Patent Application Publication No. 2021-70692; an anion having a cyclic ether group, as described in Japanese Patent Application Publication No. 2018-180525 and Japanese Patent Application Publication No. 2021-35935; and an anion described in Japanese Patent Application Publication No. 2018-92159.

[0211] As the non-nucleophilic counterions, anions of bulky benzenesulfonic acid derivatives that do not contain fluorine atoms, as described in Japanese Patent Publication No. 2006-276759, Japanese Patent Publication No. 2015-117200, Japanese Patent Publication No. 2016-65016, Japanese Patent Publication No. 2019-202974 and Japanese Patent Publication No. 2024-104830, as well as benzenesulfonic acid anions and alkylsulfonic acid anions that do not contain fluorine atoms bonded to an aromatic group containing an iodine atom, as described in Japanese Patent Publication No. 6645464. Furthermore, anions described in paragraphs

[0229] to

[0231] of Japanese Patent Publication No. 2024-77330 and paragraphs

[0033] to

[0093] of Japanese Patent Publication No. 2024-140135 can also be used.

[0212] As the non-nucleophilic counterion, other options include the bissulfonic acid anion described in Japanese Patent Publication No. 2015-206932, the sulfonamide or sulfonimide anion described in International Publication No. 2020 / 158366, which has a sulfonic acid on one end and a different sulfonamide or sulfonimide on the other, and the sulfonate anion described in Japanese Patent Publication No. 2015-24989.

[0213] In formulas (A8) and (A9), g1 and g2 are independently 0, 1, 2, or 3, but 1 is preferred.

[0214] In equation (A10), h1 is either 0 or 1. h2 is either 0, 1, 2, 3, or 4. h3 is either 0, 1, 2, 3, or 4. However, when h1 is 0, 0 ≤ h2 + h3 ≤ 4, and when h1 is 1, 0 ≤ h2 + h3 ≤ 6.

[0215] In formulas (A8), (A9), and (A10), L 1 These are single bonds, ether bonds, ester bonds, carbonyl groups, sulfonic acid ester bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Of these, ether bonds, ester bonds, and carbonyl groups are preferred from a synthetic viewpoint, and ester bonds and carbonyl groups are more preferred.

[0216] In formula (A8), Rf 1 and Rf 2 Each of these is independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Of these, Rf 1 and Rf 2 To increase the acid strength of the generated acid, it is preferable that all atoms be fluorine atoms. Rf 3 and Rf 4 These are, independently, a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Of these, Rf is used to improve solvent solubility. 3 and Rf 4 At least one of them is preferably a trifluoromethyl group.

[0217] In formula (A9), Rf 5 and Rf 6 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. However, all Rf 5 and Rf 6 These cannot simultaneously become hydrogen atoms. Of these, Rf 5 and Rf 6At least one of them is preferably a trifluoromethyl group.

[0218] In formula (A10), Rf 7 Rf is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated alkylthio group or pentafluorosulfanyl group having 1 to 6 carbon atoms. 7 Preferably, the Rf is a fluorine atom, a trifluoromethyl group, a difluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, a trifluoromethylthio group, or a difluoromethylthio group, and more preferably a fluorine atom, a trifluoromethyl group, or a trifluoromethoxy group. When h2 is 2, 3, or 4, each Rf 7 They may be the same as or different from each other.

[0219] In formula (A10), R 43 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than fluorine atoms, or heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. For example, in the explanation of formula (A1), R 1 and R 2 Examples of hydrocarbyl groups represented by the formula are similar to those exemplified, but are not limited to these. Also, when h3 is 2, 3, or 4, each R 43 They may be the same as or different from each other.

[0220] Also, when h3 is 2, 3, or 4, multiple R 43These elements may bond with each other to form a ring with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornane rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, the ring may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0221] Specific examples of anions with repeating unit A8 are listed below, but are not limited to these. Note that in the following formula, R A The same as above, and Me is a methyl group. [ka]

[0222] [ka]

[0223] [ka]

[0224] [ka]

[0225] [ka]

[0226] [ka]

[0227] [ka]

[0228] [ka]

[0229] [ka]

[0230] [ka]

[0231] [ka]

[0232] [ka]

[0233] [ka]

[0234] Other specific examples of repeating unit A8 include paragraphs

[0043] to

[0044] of International Publication No. 2024 / 176672, paragraphs

[0067] to

[0070] of International Publication No. 2024 / 176701, paragraphs

[0057] to

[0058] of International Publication No. 2024 / 190386, paragraphs

[0020] to

[0023] of Japanese Patent Publication No. 2024-103465, paragraphs

[0067] to

[0070] of Japanese Patent Publication No. 2024-120703, and paragraphs

[0075] to

[0084] of Japanese Patent Publication No. 7520258.

[0235] Specific examples of anions with repeating unit A9 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0236] [ka]

[0237] [ka]

[0238] [ka]

[0239] [ka]

[0240] [ka]

[0241] [ka]

[0242] [ka]

[0243] [ka]

[0244] [ka]

[0245] [ka]

[0246] Specific examples of anions with repeating unit A10 are shown below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0247] [ka]

[0248] [ka]

[0249] [ka]

[0250] [ka]

[0251] [ka]

[0252] [ka]

[0253] [ka]

[0254] [ka]

[0255] [ka]

[0256] [ka]

[0257] [ka]

[0258] [ka]

[0259] [ka]

[0260] [ka]

[0261] [ka]

[0262] [ka]

[0263] Specific examples of anions with repeating unit A11 are listed below, but are not limited to these. Note that in the following formula, R A This is the same as described above. [ka]

[0264] In formulas (A8) to (A11), A + This is an onium cation. The onium cation is preferably a sulfonium cation or an iodonium cation. Specific examples of the sulfonium cation include, but are not limited to, those exemplified later as specific examples of sulfonium cations represented by formula (Z-1) and those exemplified later as specific examples of sulfonium cations represented by formula (Z-3). Specific examples of the iodonium cation include, but are not limited to, those exemplified later as specific examples of iodonium cations represented by formula (Z-2).

[0265] The specific structures of repeating units A7 to A11 include any combination of anions and cations as described above.

[0266] Repeating units A7 to A11 are units that generate acid when irradiated with high-energy rays. It is believed that the inclusion of these units in the polymer moderately suppresses acid diffusion, resulting in a pattern with reduced LER. Furthermore, the inclusion of these units in the polymer suppresses the phenomenon of acid volatilizing from the exposed areas and reattaching to the unexposed areas during baking in a vacuum, which is thought to be effective in reducing LER and minimizing shape degradation due to unwanted film loss in the unexposed areas.

[0267] Of the repeating units A7 to A11, repeating units A8 to A11 are preferred for processing photomask blanks because their acid strength is optimal for suppressing acid diffusion and designing acid-unstable groups of polymers, and repeating units A9, A10, and A11 are even more preferred.

[0268] If the polymer contains repeating units A7 to A11, the content of these units is preferably 0.1 to 30 mol%, and more preferably 0.5 to 20 mol%, of the total repeating units of the polymer. Repeating units A7 to A11 may be used individually or in combination of two or more types.

[0269] The content of repeating units having an aromatic ring skeleton in the total 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. If repeating units A7 to A11 are not included, it is preferable that all units have an aromatic ring skeleton.

[0270] The polymer may contain commonly used (meth)acrylic acid ester units protected by acid-unstable groups, or (meth)acrylic acid ester units having adhesive groups such as lactone structures or hydroxyl groups other than phenolic hydroxyl groups. While these repeating units allow for fine-tuning of the properties of the resist film, they are not required to be included.

[0271] Examples of (meth)acrylic acid ester units having the aforementioned adhesive group include the repeating unit represented by the following formula (A12) (hereinafter also referred to as repeating unit A12), the repeating unit represented by the following formula (A13) (hereinafter also referred to as repeating unit A13), and the repeating unit represented by the following formula (A14) (hereinafter also referred to as repeating unit A14). These units do not exhibit acidity and can be used auxiliaryly as units that provide adhesion to the substrate or as units that adjust solubility. [ka]

[0272] In formulas (A12) to (A14), R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 51 R is either an -O- or a methylene group. 52 R is a hydrogen atom or a hydroxyl group. 53i is a saturated hydrocarbyl group having 1 to 4 carbon atoms. i is 0, 1, 2, or 3.

[0273] When repeating units A12 to A14 are included, their content is preferably 0 to 20 mol%, and more preferably 0 to 10 mol%, of the total repeating units of the polymer. Repeating units B14 to B16 may be used individually or in combination of two or more types.

[0274] The aforementioned polymer can be synthesized by copolymerizing each monomer, which is optionally protected with a protecting group, using known methods, and then performing a deprotection reaction as necessary. The copolymerization reaction is not particularly limited, but radical polymerization and anionic polymerization are preferred. For these methods, refer to Japanese Patent Application Publication No. 2004-115630.

[0275] The polymer preferably has a weight-average molecular weight (Mw) of 1,000 to 50,000, and more preferably 2,000 to 20,000. If Mw is 1,000 or more, there is no risk of phenomena such as the pattern heads becoming rounded, reducing resolution, and LER degradation, as is conventionally known. On the other hand, if Mw is 50,000 or less, there is no risk of LER degradation, especially when forming patterns with a pattern line width of 100 nm or less. In this invention, Mw is a polystyrene-converted measurement value obtained by gel permeation chromatography (GPC) using THF or DMF as a solvent.

[0276] The polymer preferably has a narrow dispersion with a molecular weight distribution (Mw / Mn) of preferably 1.0 to 2.0, more preferably 1.0 to 1.9, and even more preferably 1.0 to 1.8. When the dispersion is narrow in this way, after development, no foreign matter will be generated on the pattern, and the shape of the pattern will not deteriorate.

[0277] Furthermore, regarding the base polymer design, the dissolution rate in alkaline developer is preferably 10 nm / min or less, more preferably 7 nm / min or less, and even more preferably 5 nm / min or less. In advanced generations, when the coated film on the substrate is in the thin film region (100 nm or less), the effect of pattern film reduction on alkaline development becomes significant, and if the alkali dissolution rate of the polymer is greater than 10 nm / min, the pattern collapses, making it impossible to form fine patterns. This is particularly noticeable in the fabrication of photomasks, where defect-free conditions are required, as the development process tends to be strong. In this invention, the dissolution rate of the base polymer in alkaline developer is calculated from the amount of film reduction when a polymer solution (polymer concentration: 16.7% by mass, solvent: propylene glycol monomethyl ether acetate (PGMEA)) is spin-coated onto an 8-inch silicon wafer, baked at 100°C for 90 seconds to form a film with a thickness of 1000 nm, and then developed with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) at 23°C for 100 seconds.

[0278] The base polymer of component (A) may include other polymers other than the aforementioned polymer. Other polymers that are conventionally known as base polymers for resist compositions can be used. The content of other polymers is not particularly limited, as long as it does not impair the effects of the present invention.

[0279] [(B) Photoacid Generator] The chemically amplified positive resist composition of the present invention contains a photoacid generator consisting of an onium salt represented by the following formula (B) as component (B). [ka]

[0280] In formula (B), n1 is either 0 or 1. When n1 is 0, it is a benzene ring, and when n1 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that n1 is a benzene ring with n1 being 0. n2 is either 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, it is preferable that n2 is either 0 or 1. n3 is either 2, 3, or 4. However, when n1 is 0, 2 ≤ n2 + n3 ≤ 5, and when n1 is 1, 2 ≤ n2 + n3 ≤ 7.

[0281] In formula (B), R 101This group is a C1-C20 hydrocarbyl group which may contain a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C1-C20 hydrocarbylthio group which may contain a heteroatom, or a C1-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., but a fluorine atom or an iodine atom is preferred. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl groups; C3-C20 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; C2-C20 alkenyl groups such as vinyl, allyl, propenyl, butenyl, and hexenyl groups; C3-C20 cyclic unsaturated hydrocarbyl groups such as cyclohexenyl; C6-C20 aryl groups such as phenyl and naphthyl groups; C7-C20 aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these. 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, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- constituting the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. When n2 is 2, 3, or 4, each R 101 They may be the same as or different from each other.

[0282] Also, when n2 is 2, 3, or 4, multiple R101 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. In this case, a 5- to 8-membered ring is preferred.

[0283] In formula (B), Ar AL is an acid-unstable group-containing group represented by the following formula (AL). However, at least one Ar AL is, -SO3 - It is bonded to a carbon atom adjacent to the carbon atom to which it is bonded. [ka] (In the formula, * represents a bond.)

[0284] In formula (B), n4 is either 0 or 1. When n4 is 0, it is a benzene ring, and when n4 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that n4 is a benzene ring with n4 being 0. n5 is either 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, it is preferable that n5 is either 0 or 1. n6 is either 0, 1, 2, 3, or 4. From the viewpoint of raw material procurement, it is preferable that n6 is either 0, 1, or 2. n7 is either 1 or 2. However, when n4 is 0, 1 ≤ n5 + n6 + n7 ≤ 5, and when n4 is 1, 1 ≤ n5 + n6 + n7 ≤ 7.

[0285] In formula (B), R 102 This is a C1-C20 hydrocarbyl group which may contain a halogen atom other than a fluorine atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C1-C20 hydrocarbylthio group which may contain a heteroatom, or a C1-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. Examples of halogen atoms other than fluorine atoms include chlorine atoms, bromine atoms, iodine atoms, etc., but iodine atoms are preferred. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R 101Examples of hydrocarbyl groups represented by the above are similar to those exemplified, but are not limited to these. When n5 is 2, 3, or 4, each R 102 They may be the same as or different from each other.

[0286] Also, when n5 is 2, 3, or 4, multiple R 2 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. In this case, a 5- to 8-membered ring is preferred.

[0287] In formula (B), R F This is 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, a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms, or a pentafluorosulfanil group. Of these, it is preferably a fluorine atom, a trifluoromethyl group, a trifluoromethoxy group, a trifluoromethylthio group, or a pentafluorosulfanil group, and more preferably a fluorine atom, a trifluoromethoxy group, or a pentafluorosulfanil group. When n6 is 2, 3, or 4, each R F They may be the same as or different from each other.

[0288] In equation (B), when n6 is 2, 3, or 4, at least one R F is -OC(R L1 )(R L2 )(R L3 It is preferable that the -OC(R) is bonded to a carbon atom adjacent to the carbon atom on the aromatic ring to which it is bonded. L1 )(R L2 )(R L3 ) and R F The proximity of these elements improves the acidity of the phenols generated after deprotection of the tertiary ether, thereby increasing their affinity for alkaline developers and thus enhancing the solubility contrast.

[0289] In formula (B), R L1 and R L2 These are, independently, hydrocarbyl groups having 1 to 12 carbon atoms. L3R is a hydrogen atom or a hydrocarbyl group having 1 to 12 carbon atoms. L1 , R L2 and R L3 A portion of the -CH2- in the hydrocarbyl group represented by may be substituted with -O- or -S-, and if the hydrocarbyl group includes an aromatic ring or multiple bond, some or all of the hydrogen atoms bonded to the carbon atoms constituting the aromatic ring or multiple bond may be substituted with a halogen atom, a cyano group, a nitro group, a C1-C4 alkyl group which may contain a halogen atom, or a C1-C4 alkoxy group which may contain a halogen atom. Also, R L1 and R L2 However, they may bond to each other and form a ring with the carbon atoms to which they are bonded, and some of the -CH2- in the ring may be substituted with -O- or -S-. However, R L3 If it does not contain any alicyclic structure, aromatic ring, or multiple bond, then R L1 and R L2 These atoms are bonded to each other, forming a ring with the carbon atoms to which they are bonded, and some of the -CH2- atoms in the ring may be substituted with -O- or -S- atoms. That is, -C(R L1 )(R L2 )(R L3 The acid-unstable group represented by ) must contain at least one cyclic structure or multiple bond. L3 If it is a hydrogen atom, R L1 and R L2 It is preferable that these atoms bond to each other to form an alicyclic ring containing multiple bonds with the carbon atoms to which they bond.

[0290] In formula (B), -C(R L1 )(R L2 )(R L3 Specific examples of acid-unstable groups represented by ) are, but are not limited to, those listed below. * represents a bond with an adjacent -O-. [ka]

[0291] [ka]

[0292] [ka]

[0293] [ka]

[0294] [ka]

[0295] [ka]

[0296] [ka]

[0297] [ka]

[0298] [ka]

[0299] [ka]

[0300] [ka]

[0301] The onium salt represented by formula (B) is preferably the one represented by formula (B1) below. [ka] (In the formula, n1, n2, n3, n5, n6, n7, R 101 , R 102 , R F and R L1 ~R L3 , same as above. Z + (This will be explained later.)

[0302] The onium salt represented by formula (B1) is preferably the one represented by formula (B2) below. [ka] (In the formula, n2, n3, n5, n6, n7, R 101 , R 102 , R F and R L1 ~R L3 The same as above. Z + (This will be explained later.)

[0303] The anions of the onium salt represented by formula (B) include, but are not limited to, those listed below. The bonding positions of the various substituents on the aromatic ring may be interchanged. [ka]

[0304] [ka]

[0305] [ka]

[0306] [ka]

[0307] [ka]

[0308]

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[0309]

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[0310]

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[0311]

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[0312]

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[0313]

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[0314]

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[0315]

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[0316]

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[0317]

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[0318]

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[0319]

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[0320]

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[0321]

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[0322]

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[0323]

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[0324]

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[0325]

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[0326]

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[0327]

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[0328]

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[0329]

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[0330]

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[0331]

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[0332]

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[0333]

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[0334]

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[0335]

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[0336]

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[0337]

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[0338]

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[0339]

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[0340]

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[0341]

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[0342]

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[0343]

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[0344]

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[0345]

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[0346]

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[0347]

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[0348]

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[0349]

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[0350]

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[0351]

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[0352]

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[0353]

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[0354]

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[0355]

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[0356]

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[0357]

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[0358]

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[0359]

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[0360]

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[0361]

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[0362]

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[0363]

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[0364]

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[0366]

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[0367]

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[0368]

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[0369]

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[0370]

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[0371]

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[0372]

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[0373]

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[0374]

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[0375]

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[0376]

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[0377]

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[0378]

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[0379]

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[0380]

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[0381]

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[0382]

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[0383]

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[0384]

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[0385]

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[0386]

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[0387]

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[0388]

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[0389]

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[0390]

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[0391]

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[0392]

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[0393]

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[0394]

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[0395]

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[0396]

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[0397]

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[0398]

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[0399]

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[0400]

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[0401]

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[0402]

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[0403]

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[0404]

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[0405]

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[0406]

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[0407]

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[0408]

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[0409]

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[0410]

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[0411]

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[0412]

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[0413]

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[0414]

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[0415]

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[0416]

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[0417]

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[0418]

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[0419]

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[0420]

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[0421]

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[0422]

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[0423]

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[0424]

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[0425] [ka]

[0426] [ka]

[0427] [ka]

[0428] [ka]

[0429] [ka]

[0430] [ka]

[0431] In formula (B), Z + This is an onium cation. The onium cation is preferably a sulfonium cation represented by the following formula (Z-1) or an iodonium cation represented by the following formula (Z-2). [ka]

[0432] In equations (Z-1) and (Z-2), R ct1 ~R ct5 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom.

[0433] R ct1 ~R ct5Specific examples of halogen atoms represented by this formula include fluorine, chlorine, bromine, and iodine atoms.

[0434] R ct1 ~R ct5 The hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C30 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups; C3-C30 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; C2-C30 alkenyl groups such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl groups; C3-C30 cyclic unsaturated hydrocarbyl groups such as cyclohexenyl; C6-C30 aryl groups such as phenyl, naphthyl, and thienyl groups; C7-C30 aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these, but aryl groups are preferred. 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, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0435] Also, R ct1 and R ct2 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, specific examples of the structure of the ring include those represented by the following formula. [ka] (In the formula, the dashed line represents R ct3 (This is a combination of the two.)

[0436] Specific examples of sulfonium cations represented by formula (Z-1) include those described in paragraphs

[0102] to

[0125] of Japanese Patent Publication No. 2024-003744 and those described in paragraphs

[0070] to

[0085] of Japanese Patent Publication No. 2023-169812, but are not limited to these.

[0437] Specific examples of iodonium cations represented by formula (Z-2) include, but are not limited to, those described in paragraph

[0181] of Japanese Patent Application Publication No. 2024-000259.

[0438] Z + As an onium cation represented by the formula (Z-3) below, a sulfonium cation represented by the formula (Z-3) below is also preferred. [ka]

[0439] In formula (Z-3), m1 is either 0 or 1. When m1 is 0, it is a benzene ring, and when m1 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that m1 is a benzene ring with a value of 0. m2 is either 0 or 1. When m2 is 0, it is a benzene ring, and when m2 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that m1 is a benzene ring with a value of 0. m3 is either 0 or 1. When m3 is 0, it is a benzene ring, and when m3 is 1, it is a naphthalene ring, but from the viewpoint of solvent solubility, it is preferable that m3 is a benzene ring with a value of 0.

[0440] In formula (Z-3), m4 is 0, 1, 2, 3, or 4. The more iodine atoms in the cation structure there are, the higher the absorption, especially for EUV. However, this also leads to poor solvent solubility and concerns about precipitation in the resist composition. Therefore, m4 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0441] In formula (Z-3), 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.

[0442] In formula (Z-3), m8 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that m8 is 0 or 1. m9 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that m9 is 0 or 1. m10 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that m10 is 0 or 1.

[0443] In formula (Z-3), m11 is either 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, a benzene ring with m11 being 0 is preferred.

[0444] In formula (Z-3), m12 is 0, 1, 2, 3, or 4. The more iodine atoms in the cation structure there are, the higher the absorption, especially for EUV. However, this also leads to poor solvent solubility and concerns about precipitation in the resist composition. Therefore, m12 is preferably 0, 1, 2, or 3, and more preferably 0, 1, or 2.

[0445] In formula (Z-3), m13 is 0, 1, or 2. From the viewpoint of raw material procurement, it is preferable that m13 is 0 or 1. m14 is 0, 1, or 2. From the viewpoint of synthesis, it is preferable that m14 is 0 or 1.

[0446] 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.

[0447] In formula (Z-3), R F1 ~R F3 Each of these is 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, trifluoromethyl, trifluoromethoxy, and trifluorothiomethoxy groups are preferred. When m5 is 2, 3, or 4, each R F1 They may be the same or different from each other. When m6 is 2, 3, 4, 5 or 6, each R F2 They may be the same or different from each other. When m7 is 2, 3, 4, 5 or 6, each R F3 They may be the same as or different from each other.

[0448] In formula (Z-3), R ct6 ~R ct9 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than iodine and fluorine atoms, a nitro group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, or a C1-C20 hydrocarbylthio group which may contain a heteroatom. The hydrocarbyl portion of the hydrocarbyl group, hydrocarbyloxy group, and hydrocarbylthio group may be saturated or unsaturated, and may be linear, branched, or cyclic. For example, in the explanation of formula (A), R 1Examples of hydrocarbyl groups represented by the above are similar to those exemplified. Furthermore, some or all of the hydrogen atoms in the hydrocarbyl portion of the hydrocarbyl group, hydrocarbyloxy group and hydrocarbylthio group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, and halogen atoms, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, and nitrogen atoms, and as a result, the group may contain hydroxyl groups, cyano groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0449] Also, when m8 is 2, the two R ct6 The two Rs may be identical or different from each other. ct6 These may bond with each other to form a ring with the carbon atom to which they are bonded. When m9 is 2, two R ct7 The two Rs may be identical or different from each other. ct7 These may bond with each other to form a ring with the carbon atom to which they are bonded. When m10 is 2, two R ct8 The two Rs may be identical or different from each other. ct8 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When m13 is 2, two R ct9 The two Rs may be identical or different from each other. ct9These elements may bond with each other to form a ring with the carbon atoms to which they are bonded. Specific examples of the ring formed in this case include cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, norbornane rings, adamantane rings, etc. Furthermore, some or all of the hydrogen atoms in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- in the ring may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc. As a result, the ring may contain hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sultone rings, carboxylic acid anhydrides (-C(=O)-OC(=O)-), haloalkyl groups, etc.

[0450] Furthermore, S in the sulfonium cation represented by formula (Z-3) + Aromatic rings that are directly bonded to each other are bonded to each other, forming S + They may form a ring together. Specific examples of the ring structure include those represented by the following formula. [ka]

[0451] In formula (Z-3), L A and L B These are, independently, a single bond, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. Of these, L A The bond is preferably a single bond, an ether bond, an ester bond, or a sulfonic acid ester bond, and more preferably an ester bond or a sulfonic acid ester bond. B The bond is preferably a single bond, an ether bond, or an ester bond, and more preferably a single bond.

[0452] In formula (Z-3), X LThis is a 1-40 carbon atom hydrocarbylene group which may contain single bonds or heteroatoms. The hydrocarbylene group may be linear, branched, or cyclic, and specific examples include an alkanediyl group and a cyclic saturated hydrocarbylene group. Specific examples of the heteroatom include an oxygen atom, a nitrogen atom, and a sulfur atom.

[0453] X L Specific examples of C1-C40 hydrocarbylene groups that may contain heteroatoms represented by the formulas shown below are, but are not limited to, those shown below. In the formulas below, * represents L A and L B This represents a combination of two things. [ka]

[0454] [ka]

[0455] [ka]

[0456] [ka]

[0457] Of these, X L -0~X L -22 and X L -47~X L -61 is preferred.

[0458] The sulfonium cation represented by formula (Z-3) is preferably the one represented by formula (Z-3-1) below. [ka] (In the formula, m4~m10, m12~m14, R F1 ~RF3 , R ct6 ~R ct9 , L A , L B and X L (This is the same as above.)

[0459] The cation represented by formula (Z-3-1) is preferably the one represented by formula (Z-3-2) below. [ka] (In the formula, m4~m10, R F1 ~R F3 and R ct6 ~R ct8 (This is the same as above.)

[0460] Specific examples of sulfonium cations represented by formula (Z-3) are listed below, but are not limited to these. In the following formula, Me represents a methyl group. [ka]

[0461] [ka]

[0462] [ka]

[0463] [ka]

[0464] [ka]

[0465] [ka]

[0466]

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[0467]

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[0468]

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[0469]

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[0470]

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[0471]

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[0472]

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[0473]

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[0474]

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[0475]

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[0476]

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[0477]

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[0478]

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[0479]

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[0480]

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[0481]

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[0482]

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[0483]

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[0484]

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[0485]

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[0486]

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[0487] [ka]

[0488] Specific examples of the onium salt include any combination of the anion and cation mentioned above.

[0489] The onium salt can be synthesized by known methods. Specifically, it can be synthesized using the synthesis examples described in paragraphs

[0363] to

[0368] of Japanese Patent Publication No. 7032549, but the synthesis method is not limited to this.

[0490] In the chemically amplified resist composition of the present invention, the onium salt represented by formula (B) is an onium salt of an aromatic sulfonic acid, and therefore can generate an acid of appropriate intensity by high-energy ray irradiation. Furthermore, the onium salt is -SO3 - It is characterized by having two, three, or four aryl groups with ether-type acid-unstable groups on the aromatic ring to which it is bonded. -SO3 - The aryl group attached to the aromatic ring to which it is bonded must have at least one -SO3 group. - It is preferable that it bonds to a carbon atom adjacent to the carbon atom to which it is bonded, and the two are -SO3 - It is more preferable that it bonds to a carbon atom adjacent to the carbon atom to which it is bonded. -SO3 -When bulky aromatic rings are bonded to the carbon atoms adjacent to the carbon atom to which the ether-type acid-unstable group is bonded, the vicinity of the generated sulfonic acid is shielded, thereby suppressing excessive deprotection of the acid-unstable group of the base polymer. The ether-type acid-unstable group is preferably a cyclic tertiary ether. In this case, the cyclic structure lowers the activation energy of the acid elimination reaction, making the deprotection reaction easier to proceed. On the other hand, if the ether-type acid-unstable group does not have a cyclic ether structure, the carbon atom bonded to the ether oxygen has at least one double bond, aromatic ring, or triple bond. In either case, the formation of an allyl cation, benzyl cation, or propargyl cation acts as a driving force, making the acid-induced deprotection reaction easier to proceed. Japanese Patent Publication No. 7032549 describes structures into which tert-butyl ether, acetal, acetal, tert-butoxycarbonyl, and tert-butyl ester are introduced as acid-unstable groups. However, acetal and tert-butoxycarbonyl are functional groups that are highly sensitive to acid, raising concerns about storage stability. Furthermore, tert-butyl ether and tert-butyl ester have high activation energies for acid-induced deprotection reactions, making it difficult for sufficient deprotection reactions to proceed. In the onium salt represented by formula (A), it is preferable that a fluorine atom or a functional group containing a fluorine atom is bonded to the carbon atom adjacent to the carbon atom to which the ether-type acid-unstable group is bonded. The fluorine atom or a functional group containing a fluorine atom can increase solubility in solvents and allow for uniform dissolution in solvents. In addition, although phenols are produced after the acid-induced deprotection reaction of the ether-type acid-unstable group, the acidity of the phenols can be increased by having a fluorine atom or a functional group containing a fluorine atom in an adjacent position. Phenols have the characteristic of not swelling easily in alkaline developers, and when developed with an alkaline developer, their affinity for the alkaline developer increases, which can improve dissolution contrast while suppressing development residue in the exposed areas. Patent No. 7531671 describes an aromatic sulfonic acid anion with a tertiary ester-type acid-unstable group introduced as a similar structure. Tertiary esters generate a carboxyl group after the acid-deprotection reaction proceeds, but are known to swell in alkaline developers.This degrades the LER of the resist pattern. Multiple aromatic rings in the anion improve compatibility with the aromatic rings of the base polymer through mutual interaction (π-π stacking interaction), which is expected to suppress excessive acid diffusion. Due to these effects, an acid with controlled acid strength and diffusion can be uniformly generated in the resist film, resulting in fine patterns with good resolution and low LER. In positive-type resist compositions using alkaline developers, a pattern with good rectangularity can be obtained due to appropriate dissolution inhibition.

[0491] In the chemically amplified positive resist composition of the present invention, the content of (B) photoacid generator is preferably 0.1 to 40 parts by mass, and more preferably 1 to 20 parts by mass, per 80 parts by mass of (A) base polymer. When the content of (B) photoacid generator is within the above range, the amount of acid necessary for deprotection of acid-unstable groups is generated, and storage stability is also good. (B) photoacid generator may be used alone or in combination of two or more types.

[0492] [(C) Organic Solvents] The chemically amplified positive resist composition of the present invention may contain an organic solvent as component (C). The organic solvent is not particularly limited as long as it can dissolve 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] to

[0145] of Japanese Patent Application Publication No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; and propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples 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 using acid-unstable acetal groups, high-boiling point alcoholic solvents, specifically diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol, can be added to accelerate the deprotection reaction of the acetal.

[0493] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, and mixtures thereof are preferred.

[0494] If the chemically amplified positive resist composition of the present invention contains (C) an organic solvent, its content is preferably 200 to 10,000 parts by mass, and more preferably 400 to 5,000 parts by mass, per 80 parts by mass of the (A) base polymer. The (C) organic solvent may be used alone or as a mixture of two or more types.

[0495] [(D) Quencher] The chemically amplified positive resist composition of the present invention may optionally contain a quencher as component (D). In this invention, a quencher refers to a compound that traps the acid generated from the acid generator. This suppresses the diffusion rate of the acid generated from the acid generator when it diffuses into the resist film, and even when a substrate with a chromium-containing material on its outermost surface is used as the substrate, the influence of the acid generated in the resist film on the chromium-containing material can be suppressed.

[0496] Examples of the quencher include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, hybrid amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, and the like. In particular, primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Publication No. 2008-111103 are preferred, especially amine compounds having a hydroxyl group, ether bond, ester bond, lactone ring, cyano group, or sulfonic acid ester bond, or compounds having a carbamate group described in Japanese Patent Publication No. 3790649. Preferred examples include tris[2-(methoxymethoxy)ethyl]amine, tris[2-(methoxymethoxy)ethyl]amine-N-oxide, dibutylaminobenzoic acid, morpholine derivatives, and imidazole derivatives. By adding such basic compounds, it is possible to further suppress the diffusion rate of the acid in the resist film or correct its shape, for example.

[0497] Furthermore, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of carboxylic acids whose α-position is not fluorinated, as described in Japanese Patent Publication No. 2008-158339. Sulfonic acids, imido acids, or methidic acids with α-position fluorinated are necessary for deprotecting acid-unstable groups, but salt exchange with onium salts whose α-position is not fluorinated releases carboxylic acids whose α-position is not fluorinated. Carboxylic acids whose α-position is not fluorinated hardly undergo deprotection reactions and therefore function as quenchers.

[0498] Examples of onium salts of carboxylic acids whose α-position is not fluorinated include those represented by the following formula (D1). [ka]

[0499] In formula (D1), R 201 This refers to a hydrocarbyl group having 1 to 40 carbon atoms, which may contain hydrogen atoms or heteroatoms, but excludes those in which the hydrogen atom bonded to the carbon atom at the α position of the carboxyl group is substituted with a fluorine atom or a fluoroalkyl group.

[0500] R 201 The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples 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 with 3 to 40 carbon atoms, such as decyl group, adamantyl group, and adamantylmethyl group; C2 to 40 alkenyl groups, such as vinyl group, allyl group, propenyl group, butenyl group, and hexenyl group; C3 to 40 cyclic unsaturated aliphatic hydrocarbyl groups, such as cyclohexenyl group; phenyl group, naphthyl group, alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-methylphenyl group) Examples include aryl groups having 6 to 40 carbon atoms, such as ethylphenyl group, 4-n-butylphenyl group, di- or trialkylphenyl group (2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group, etc.), alkylnaphthyl group (methylnaphthyl group, ethylnaphthyl group, etc.), and dialkylnaphthyl group (dimethylnaphthyl group, diethylnaphthyl group, etc.); and aralkyl groups having 7 to 40 carbon atoms, such as benzyl group, 1-phenylethyl group, and 2-phenylethyl group.

[0501] 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, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain a hydroxyl group, a cyano group, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Examples of hydrocarbyl groups containing heteroatoms include heteroaryl groups such as thienyl groups; alkoxyphenyl groups such as 4-hydroxyphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 4-tert-butoxyphenyl, and 3-tert-butoxyphenyl groups; alkoxynaphthyl groups such as methoxynaphthyl, ethoxynaphthyl, n-propoxynaphthyl, and n-butoxynaphthyl groups; dialkoxynaphthyl groups such as dimethoxynaphthyl and diethoxynaphthyl groups; and aryloxoalkyl groups such as 2-aryl-2-oxoethyl groups such as 2-phenyl-2-oxoethyl, 2-(1-naphthyl)-2-oxoethyl, and 2-(2-naphthyl)-2-oxoethyl groups.

[0502] In formula (D1), Mq A + This is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation, or an ammonium cation, and more preferably a sulfonium cation or an iodonium cation. Specific examples of the sulfonium cation are the same as those exemplified as specific examples of the sulfonium cation represented by formula (Z-1) and the sulfonium cation represented by formula (Z-3). Specific examples of the iodonium cation are the same as those exemplified as specific examples of the iodonium cation represented by formula (Z-2).

[0503] The anions of the onium salt represented by formula (D1) include, but are not limited to, those listed below. [ka]

[0504] [ka]

[0505] [ka]

[0506] [ka]

[0507] As the quencher, a sulfonium salt of an iodized benzene ring-containing carboxylic acid represented by the following formula (D2) can also be suitably used. [ka]

[0508] In equation (D2), s is 1, 2, 3, 4, or 5. t is 0, 1, 2, or 3, where 1 ≤ s + t ≤ 5. u is 1, 2, or 3.

[0509] In formula (D2), R 211 This includes hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, amino groups, nitro groups, cyano groups, saturated hydrocarbyl groups with 1 to 6 carbon atoms, saturated hydrocarbyloxy groups with 1 to 6 carbon atoms, saturated hydrocarbylcarbonyloxy groups with 2 to 6 carbon atoms, saturated hydrocarbylsulfonyloxy groups with 1 to 4 carbon atoms, and -N(R 211A )-C(=O)-R 211B or -N(R 211A )-C(=O)-OR 211BThe saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, or saturated hydrocarbylsulfonyloxy group may have some or all of its hydrogen atoms substituted with halogen atoms. 211A R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 211B is 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 are 2 or more, each R 211 They may be the same or different from one another.

[0510] In formula (D2), L 21 This is a single bond or a (u+1) valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxyl group, and a carboxyl group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic.

[0511] In formula (D2), R 212 , R 213 and R 214 Each of these is a C1-C20 hydrocarbyl group which may independently contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include C1-C20 alkyl groups, C2-C20 alkenyl groups, C6-C20 aryl groups, C7-C20 aralkyl groups, etc. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxyl group, carboxyl group, halogen atom, oxo group, cyano group, nitro group, sultone ring, sulfo group, or sulfonium salt-containing group, and some of the -CH2- of the hydrocarbyl group may be substituted with an ether bond, ester bond, carbonyl group, amide bond, carbonate bond, or sulfonic acid ester bond. 212 and R 213However, they may bond with each other to form a ring with the sulfur atom to which they are bonded.

[0512] A specific example of the compound represented by formula (D2) is the one described in Japanese Patent Publication No. 2017-219836. The compound represented by formula (D2) exhibits high absorption, high sensitization effect, and high acid diffusion control effect.

[0513] As the quencher, a nitrogen atom-containing carboxylate compound represented by the following formula (D3) can also be used. [ka]

[0514] In equation (D3), R 221 ~R 224 These are, independently, hydrogen atoms and -L 22 -CO2 - or a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. 221 and R 222 And, R 222 and R 223 or R 223 and R 224 These may bond with each other to form a ring with the carbon atom to which they are bonded. 22 R is a hydroxylene group having 1 to 20 carbon atoms, which may contain single bonds or heteroatoms. 225 This is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a hydrogen atom or a heteroatom.

[0515] In equation (D3), ring R r This is a ring having 2 to 6 carbon atoms, including carbon and nitrogen atoms in the formula, and some or all of the hydrogen atoms bonded to the carbon atoms of the ring are a hydrocarbyl group having 1 to 20 carbon atoms, or -L 22 -CO2 -The ring may be substituted with a sulfur atom, an oxygen atom, or a nitrogen atom. The ring may be an alicyclic ring or an aromatic ring, and is preferably a 5-membered or 6-membered ring. Specific examples include pyridine rings, pyrrole rings, pyrrolidine rings, piperidine rings, pyrazole rings, imidazoline rings, pyridazine rings, pyrimidine rings, pyrazine rings, imidazoline rings, oxazole rings, thiazole rings, morpholine rings, thiazine rings, triazole rings, and the like.

[0516] The onium carboxylate salt represented by formula (D3) contains at least one -L 22 -CO2 - It has a group. That is, R 221 ~R 224 At least one of them is -L 22 -CO2 - is and / or ring R r At least one hydrogen atom bonded to the carbon atom is -L 22 -CO2 - It has been replaced with this.

[0517] In equation (D3), MQ B + This is a sulfonium cation, an iodonium cation, or an ammonium cation, but a sulfonium cation is preferred. Specific examples of the sulfonium cation include those similar to those exemplified as specific examples of the sulfonium cation represented by formula (Z-1) and formula (Z-3).

[0518] The anions of the compound represented by formula (D3) include, but are not limited to, those listed below. [ka]

[0519] [ka]

[0520] [ka]

[0521] [ka]

[0522] [ka]

[0523] [ka]

[0524] Furthermore, a weak acidic betaine-type compound can also be used as the quencher. Specific examples are listed below, but are not limited to these. [ka]

[0525] As an example of the aforementioned quencher, a polymer-type quencher described in Japanese Patent Publication No. 2008-239918 can be cited. This enhances the rectangularity of the resist pattern by oriented on the surface of the resist film. The polymer-type quencher also has the effect of preventing film thinning of the pattern and rounding of the pattern top when a protective film for immersion lithography is applied.

[0526] If the chemically amplified positive resist composition of the present invention contains (D) a quencher, its content is preferably 0 to 50 parts by mass, and more preferably 0.1 to 40 parts by mass, relative to 80 parts by mass of the (A) base polymer. The quencher may be used alone or in combination of two or more types.

[0527] [(E) Fluorine atom-containing polymer] The chemically amplified positive resist composition of the present invention may contain a fluorine atom-containing polymer as component (E) for the purpose of increasing contrast, suppressing chemical flare of acids during high-energy ray irradiation, shielding from acid mixing from the antistatic film during the process of coating the resist film with an antistatic film material, and suppressing unexpected and unwanted pattern degradation. This polymer may further contain at least one selected from the following repeating units: repeating unit (E1) (hereinafter also referred to as repeating unit E1), repeating unit (E2) (hereinafter also referred to as repeating unit E2), repeating unit (E3) (hereinafter also referred to as repeating unit E3), and repeating unit (E4) (hereinafter also referred to as repeating unit E4), and may also contain at least one selected from the following repeating units: repeating unit (E5) (hereinafter also referred to as repeating unit E5) and repeating unit (E6) (hereinafter also referred to as repeating unit E6). Since the fluorine atom-containing polymer also functions as a surfactant, it can prevent the re-adhesion of insoluble substances to the substrate that may occur during the development process, thus also exhibiting an effect against development defects. [ka]

[0528] In equations (E1) to (E6), j1 is 1, 2, or 3. j2 is an integer satisfying 0 ≤ j2 ≤ 5 + 2(j3) - j1. j3 is 0 or 1. k is 1, 2, or 3. R B These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. C Each of these is independently either a hydrogen atom or a methyl group. 301 , R 302 , R 304 and R 305 Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. 303 , R 306 , R 307 and R 308 Each of these is independently a hydrogen atom, a C1-C15 hydrocarbyl group, a C1-C15 fluorinated hydrocarbyl group, or an acid-unstable group, and R303 , R 306 , R 307 and R 308 When is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be interposed between the carbon-carbon bonds. 309 This is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms, which may have a hydrogen atom or a group containing a heteroatom between the carbon-carbon bonds. When j1 is 2 or 3, each R 309 These may be identical or different from each other. 310 This is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms, which may have a heteroatom interposed between the carbon-carbon bonds. When j2 is 2 or more, each R 310 These may be identical or different from each other. 311 This 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 a portion of the -CH2- of the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. 1 This is a (k+1) valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1) valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. 2 The bond is a single bond, *-C(=O)-O- or *-C(=O)-N(H)-. * represents a bond with a carbon atom in the main chain. W 3 These are single bonds, -O-, *-C(=O)-OW 31 -W 32 -or *-C(=O)-N(H)-W 31 -W 32 - is. W 31 This is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 A is a single bond, ester bond, ether bond, or sulfonamide bond. * indicates a bond with a carbon atom of the main chain.

[0529] In equations (E1) and (E2), R 301 , R 302 , R 304 and R 305The saturated hydrocarbyl group having 1 to 10 carbon atoms, represented by , may be linear, branched, or cyclic. Specific examples 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 groups; and cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, adamantyl, and norbornyl groups. Of these, saturated hydrocarbyl groups having 1 to 6 carbon atoms are preferred.

[0530] In formulas (E1) to (E4), R 303 , R 306 , R 307 and R 308 The C1-C15 hydrocarbyl group represented by can be linear, branched, or cyclic. Specific examples include C1-C15 alkyl groups, C2-C15 alkenyl groups, and C2-C15 alkynyl groups, but C1-C15 alkyl groups are preferred. Examples of alkyl groups include, in addition to those mentioned above, 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 groups. Fluorinated hydrocarbyl groups include groups in which some or all of the hydrogen atoms bonded to the carbon atoms of the hydrocarbyl group mentioned above are substituted with fluorine atoms.

[0531] In formula (E4), W 1 Examples of (k+1) valent hydrocarbon groups having 1 to 20 carbon atoms, represented by , include alkyl groups having 1 to 20 carbon atoms or cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms from which k hydrogen atoms have been removed. 1Examples of (k+1) valent fluorinated hydrocarbon groups having 1 to 20 carbon atoms, as represented by the formula, include groups in which at least one hydrogen atom of the aforementioned (k+1) valent hydrocarbon group is substituted with a fluorine atom.

[0532] Specific examples of repeating units E1 to E4 are shown below, but are not limited to these. Note that in the following formula, R B This is the same as described above. [ka]

[0533] [ka]

[0534] [ka]

[0535] In formula (E5), R 309 and R 310 Examples of C1-C5 hydrocarbyl groups represented by include alkyl groups, alkenyl groups, and alkynyl groups, but alkyl groups are preferred. Examples of alkyl groups include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, sec-butyl groups, and n-pentyl groups. In addition, a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom may be interposed between the carbon-carbon bonds of the hydrocarbyl group.

[0536] In formula (E5), -OR 309 It is preferable that R is a hydrophilic group. In this case, R 309 Preferred elements include hydrogen atoms, C1-C5 alkyl groups with oxygen atoms interposed between carbon-carbon bonds, etc.

[0537] In formula (E5), W 2 It is preferable that *-C(=O)-O- or *-C(=O)-N(H)-. Furthermore, R CIt is preferable that it is a methyl group. 2 The presence of a carbonyl group improves the acid trapping ability derived from the antistatic film. Also, R C When the group is a methyl group, a more rigid polymer with a higher glass transition temperature (Tg) is formed, thus suppressing acid diffusion. This results in good temporal stability of the resist film, and the resolution and pattern shape do not deteriorate.

[0538] Examples of repeating units E5 include, but are not limited to, those listed below. Note that in the following formula, R C This is the same as described above. [ka]

[0539] [ka]

[0540] In formula (E6), W 3 The saturated hydrocarbylene group having 1 to 10 carbon atoms, represented by , may be linear, branched, or cyclic. Specific examples include methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, propane-2,2-diyl group, butane-1,1-diyl group, butane-1,2-diyl group, butane-1,3-diyl group, butane-2,3-diyl group, butane-1,4-diyl group, and 1,1-dimethylethane-1,2-diyl group.

[0541] In formula (E6), R 311 A saturated hydrocarbyl group having 1 to 20 carbon atoms, represented by , in which at least one hydrogen atom is substituted with a fluorine atom, may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 20 carbon atoms or cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom.

[0542] Examples of repeating units E6 include, but are not limited to, those listed below. Note that in the following formula, R C This is the same as described above. [ka]

[0543] [ka]

[0544] [ka]

[0545] [ka]

[0546] The content of repeating units E1 to E4 is preferably 15 to 95 mol%, and more preferably 20 to 85 mol%, of the total repeating units of the fluorine atom-containing polymer. The content of repeating units E5 and / or E6 is preferably 5 to 85 mol%, and more preferably 15 to 80 mol%, of the total repeating units of the fluorine atom-containing polymer. Repeating units E1 to E6 may be used individually or in combination of two or more types.

[0547] (E) The fluorine atom-containing polymer may contain other repeating units besides those described above. Examples of such repeating units include those described in paragraphs

[0046] to

[0078] of Japanese Patent Application Publication No. 2014-177407. (E) If the fluorine atom-containing polymer contains other repeating units, the content thereof is preferably 50 mol% or less of the total repeating units of the fluorine atom-containing polymer.

[0548] (E) Fluorine atom-containing polymers can be synthesized by known methods, which involve copolymerizing each monomer, optionally protected with a protecting group, and then performing a deprotection reaction as necessary. The copolymerization reaction is not particularly limited, but radical polymerization and anionic polymerization are preferred. For these methods, refer to Japanese Patent Application Publication No. 2004-115630.

[0549] (E) The Mw of the fluorine atom-containing polymer is preferably 2000 to 50000, and more preferably 3000 to 20000. If the Mw is 2000 or higher, the acid does not diffuse, the resolution does not deteriorate, and the stability over time is not impaired. If the Mw is 50000 or lower, the solubility in the solvent is sufficient, and coating defects do not occur. Furthermore, the Mw / Mn of the (E) fluorine atom-containing polymer is preferably 1.0 to 2.2, and more preferably 1.0 to 1.7.

[0550] When the chemically amplified positive resist composition of the present invention contains (E) a fluorine atom-containing polymer, its content is preferably 0.01 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass, per 80 parts by mass of (A) the base polymer. (E) The fluorine atom-containing polymer may be used alone or in combination of two or more types.

[0551] [(F) Other photoacid generators] The chemically amplified positive resist composition of the present invention may contain, as component (F), a photoacid generator other than the onium salt represented by formula (B) (hereinafter also referred to as "other photoacid generators"). The other photoacid generator is not particularly limited as long as it is a compound that generates acid upon irradiation with high-energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxiimide, oxime-O-sulfonate type photoacid generators, and the like.

[0552] Specific examples of the aforementioned other photoacid generators include nonafluorobutanesulfonate, partially fluorinated sulfonate described in paragraphs

[0247] to

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

[0261] to

[0265] of JP 2013-101271, the one described in paragraphs

[0122] to

[0142] of JP 2008-111103, the one described in paragraphs

[0080] to

[0081] of Japanese Patent No. 5368270, the one described in paragraphs

[0027] to

[0029] of Japanese Patent No. 6248882, the one described in paragraphs

[0029] to

[0034] of Japanese Patent No. 6648726, and the one described in paragraphs

[0028] to

[00] of Japanese Patent No. 7067271. Examples include those described in

[29] , paragraphs

[0037] to

[0060] of Japanese Patent Publication No. 2024-104830, paragraphs

[0040] to

[0071] of Japanese Patent Publication No. 2025-000201, paragraphs

[0039] to

[0066] of Japanese Patent Publication No. 2023-177038, paragraphs

[0033] to

[0093] of Japanese Patent Publication No. 2024-140135, paragraphs

[0220] to

[0225] of Japanese Patent Publication No. 7032549, paragraphs

[0229] to

[0231] of Japanese Patent Publication No. 2024-077330, and paragraphs

[0056] to

[0059] of International Publication No. 2024 / 241820. Among the above specific examples, arene sulfonate or alkane sulfonate type photoacid generators are preferred because they generate an acid of appropriate strength for deprotecting the acid-unstable group of repeating unit B2.

[0553] Examples of the photoacid generator include, but are not limited to, salt compounds containing anions with the following structures. [ka]

[0554] [ka]

[0555] [ka]

[0556] [ka]

[0557] [ka]

[0558] [ka]

[0559] (F) In other photoacid generators, a sulfonium cation or an iodonium cation is preferred as the cation paired with the anion described above. Specific examples of the sulfonium cation include, but are not limited to, those exemplified as specific examples of the sulfonium cation represented by formula (Z-1) or the sulfonium cation represented by formula (Z-3). Specific examples of the iodonium cation include, but are not limited to, those exemplified as specific examples of the iodonium cation represented by formula (Z-2).

[0560] The acid generated by the aforementioned other photoacid generators is preferably of a pKa of -2.0 or higher, and more preferably of -1.0 or higher. Furthermore, the upper limit of the pKa is preferably 2.0. The pKa values ​​were calculated using the pKa DB in the ACD / Chemsketch ver:9.04 software from Advanced Chemistry Development, Inc.

[0561] If the chemically amplified positive resist composition of the present invention contains (F) other photoacid generators, the content thereof is preferably 1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 80 parts by mass of the (A) base polymer. By including other photoacid generators, the amount of acid generated in the exposed areas and the dissolution inhibition of the unexposed areas can be appropriately adjusted. (F) Other photoacid generators may be used alone or in combination of two or more.

[0562] [(G) Surfactants] The chemically amplified positive resist composition of the present invention may contain a commonly used surfactant as component (G) to improve its applicability to substrates. Numerous surfactants are known, as described in International Publication No. 2006 / 121096, Japanese Patent Publication No. 2008-102383, Japanese Patent Publication No. 2008-304590, Japanese Patent Publication No. 2004-115630, and Japanese Patent Publication No. 2005-8766, and can be selected by reference thereto.

[0563] If the chemically amplified positive resist composition of the present invention contains (G) surfactant, its content is preferably 2 parts by mass or less, more preferably 1 part by mass or less, and preferably 0.01 parts by mass or more, per 80 parts by mass of (A) base polymer. (G) surfactant may be used alone or in combination of two or more types.

[0564] [Method for forming a resist pattern] The resist pattern formation method of the present invention includes the steps of forming a resist film on a substrate using the chemically amplified positive-type resist composition described above, irradiating the resist film with a pattern using high-energy rays (i.e., exposing the resist film with high-energy rays), and developing the resist film irradiated with the pattern using an alkaline developer to obtain a resist pattern.

[0565] As the substrate, for example, substrates for integrated circuit manufacturing (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coatings, etc.) or substrates for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, Si, SiO, SiO2, etc.) can be used. 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 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.

[0566] Next, the resist film is exposed using high-energy rays to irradiate a pattern. Examples of such high-energy rays include ultraviolet rays, far-ultraviolet rays, excimer laser light (KrF, ArF, etc.), EB, EUV, X-rays, gamma rays, and synchrotron radiation.

[0567] When using ultraviolet light, far ultraviolet light, excimer laser light, EUV, X-rays, gamma rays, or synchrotron radiation as the high-energy rays, a mask is used to form the desired pattern, and the exposure amount is preferably 1 to 300 mJ / cm². 2 More preferably 10-200 mJ / cm² 2 Irradiate in such a manner. When using EB as the high-energy beam, the exposure dose is preferably 1 to 300 μC / cm². 2 More preferably 10-200 μC / cm 2 The image is drawn directly in this manner. Furthermore, the chemically amplified positive resist composition of the present invention is particularly useful for EUV or EB lithography.

[0568] In addition to conventional exposure methods, immersion methods, which involve inserting a liquid between the mask and the resist film, can also be used in some cases. In such cases, a water-insoluble protective film can be used.

[0569] Next, post-exposure baking (PEB) is performed on a hot plate, preferably at 60-150°C for 1-20 minutes, more preferably at 80-140°C for 1-10 minutes.

[0570] Subsequently, the substrate is developed using a developer solution, preferably an alkaline aqueous solution such as a 0.1-5% by mass, more preferably 2-3% by mass TMAH aqueous solution, for 0.1-3 minutes, preferably 0.5-2 minutes, by a conventional method such as the dip method, puddle method, or spray method, thereby forming the desired pattern on the substrate.

[0571] The chemically amplified positive resist composition of the present invention is particularly useful when used under conditions requiring high etching resistance, minimal change in pattern line width even when the time from exposure to PEB is extended, and a low LER (Low Emission Rate). Furthermore, the chemically amplified positive resist composition of the present invention is particularly useful for application to substrates having a surface material that is prone to pattern peeling or pattern collapse due to difficulty in achieving good adhesion of the resist pattern. Examples of such substrates include substrates in which a chromium compound containing one or more light elements selected from metallic chromium, 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. [Examples]

[0572] The present invention will be specifically described below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. The apparatus used is as follows. • IR: NICOLET 6700 manufactured by Thermo Fisher Scientific · 1 H-NMR: ECA-500 manufactured by JEOL Ltd. • MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0573] [1] Synthesis of onium salts [Synthesis Example 1-1] Synthesis of Onium Salt PAG-1 [ka]

[0574] (1) Synthesis of onium salt PAG-1 Under a nitrogen atmosphere, 8.7 g of starting material SM-1, an aqueous solution of starting material SM-2 (30.5 g, equivalent to 25.1 mol), and methylene chloride (50 g) were added to a reaction vessel. After stirring for 15 minutes, the organic layer was separated, washed with water, and then concentrated under reduced pressure. Methyl isobutyl ketone (50 g) was added to the concentrate and azeotropic dehydration was performed. Diisopropyl ether was then added and crystallized to obtain 16.7 g of the target product PAG-1 as white crystals (yield 95%).

[0575] The IR spectral data and TOF-MS results for PAG-1 are shown below. Also, the nuclear magnetic resonance spectrum ( 1 The results of 1H-NMR / DMSO-d6 are shown in Figure 1. IR(D-ATR): ν= 3067, 2965, 2870, 1606, 1585, 1505, 1468, 1439, 1376, 1327, 1273, 1229, 1206, 1124, 1061, 1017, 1003, 927, 889, 856, 833, 758, 706, 667, 608, 557, 534, 494, 481, 437 cm -1 . MALDI TOF-MS: POSITIVE M + 277(C 18 H 13 OS + equivalent) NEGATIVE M - 679(C 42 H 47 O6S - equivalent)

[0576] [Synthesis Examples 1-2 to 1-10] Synthesis of Onium Salts PAG-2 to PAG-10 Using corresponding raw materials and known organic synthesis reactions, onium salts PAG-2 to PAG-10, represented by the following formulas, were synthesized. [ka]

[0577] [ka]

[0578] [Comparative Synthesis Examples 1-1 to 1-5] Synthesis of comparative onium salts PAG-A to PAG-E Using corresponding raw materials and known organic synthesis reactions, comparative onium salts PAG-A to PAG-E, represented by the following formulas, were synthesized. [ka]

[0579] [2] Polymer synthesis The monomers used in the synthesis of the polymer are as follows: [ka]

[0580] [ka]

[0581] [ka]

[0582] [ka]

[0583] [ka]

[0584] [ka]

[0585] [ka]

[0586] [Synthesis Example 2-1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, monomer A-1 (45.1 g), monomer B-1 (54.9 g), V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) 7.52 g, and PGMEA (propylene glycol monomethyl ether acetate) 139 g were placed in a flask to prepare a monomer-polymerization initiator solution. In another flask under a nitrogen atmosphere, 46 g of PGMEA was placed and heated to 80°C with stirring, and then the monomer-polymerization initiator solution was added dropwise over 4 hours. After the addition was complete, the polymerization solution was kept at 80°C and stirred for 2 hours, then cooled to room temperature. The obtained polymerization solution was added dropwise to 3000 g of hexane that had been vigorously stirred, and the precipitated polymer was filtered off. The obtained polymer was washed twice with 600 g of hexane, and then vacuum dried at 50°C for 20 hours to obtain a white powdery polymer P-1 (yield 81.1 g, yield 81%). The Mw of polymer P-1 was 5700, and the Mw / Mn ratio was 1.41. Note that Mw is a polystyrene-converted value measured using GPC with THF as the solvent. [ka]

[0587] [Synthesis Examples 2-2 to 2-54, Comparative Synthesis Examples 2-1 to 2-25] Synthesis of polymers P-2 to P-54 and comparative polymers CP-1 to CP-25 Except for changing the type and mixing ratio of each monomer, polymers P-2 to P-54 shown in Tables 1 and 2 below, and comparative polymers CP-1 to CP-25 shown in Table 3 below were synthesized using the same method as in Synthesis Example 2-1. Note that the introduction rates in Tables 1 to 3 below are in mole percent.

[0588] [Table 1]

[0589] [Table 2]

[0590] [Table 3]

[0591] The dissolution rate of the polymers in the alkaline developer was calculated by spin-coating an 8-inch silicon wafer with the polymer solution (polymer concentration: 16.7% by mass, solvent: PGME), baking it at 100°C for 90 seconds to form a film with a thickness of 1000 nm, and then developing it in a 2.38% by mass TMAH aqueous solution at 23°C for 100 seconds, measuring the amount of film loss. As a result, the dissolution rates of polymers P-1 to P-54 were 10 nm / min or less. The dissolution rates of comparative polymers CP-1 to CP-25 were also 10 nm / min or less.

[0592] [3] Preparation of chemically amplified positive resist compositions [Examples 1-1 to 1-90, Comparative Examples 1-1 to 1-57] Chemically amplified positive resist compositions were prepared by dissolving each component in an organic solvent with the compositions shown in Tables 4 to 7 below, and filtering the resulting solutions through a 5 nm nylon filter and a 1 nm UPE filter. The organic solvent was a mixed solvent consisting of 940 parts by mass of PGMEA, 1870 parts by mass of EL, and 1870 parts by mass of PGME.

[0593] [Table 4]

[0594] [Table 5]

[0595] [Table 6]

[0596] [Table 7]

[0597] In Tables 4-7, the photoacid generators PAG-Y and PAG-Z for blending, the quenchers SQ-1 to SQ-4, and the fluorine atom-containing polymers FP-1 to FP-5 are as follows: [ka]

[0598] [ka]

[0599] [ka]

[0600] [4] EB lithography evaluation [Examples 2-1 to 2-90, Comparative Examples 2-1 to 2-60] Each chemically amplified positive resist composition (R-1 to R-90, CR-1 to CR-60) was spin-coated onto a 152 mm square reflective mask blank for EUV exposure, with a chromium compound on its outermost surface, using ACT-M (manufactured by Tokyo Electron Ltd.). The blanks were then 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 obtained resist film was measured using an optical measuring instrument, NanoSpec (manufactured by Nanometrics). Measurements were taken at 81 locations within the plane of the blank substrate, excluding the outer edge portion up to 10 mm inward from the outer edge, and the average thickness and thickness range were calculated.

[0601] Next, exposure was performed using an electron beam lithography system (EBM-5000plus, manufactured by Newflare Technology Co., Ltd., accelerating voltage 50kV), followed by PEB at 110°C for 600 seconds, and development with a 2.38 mass% TMAH aqueous solution to obtain a positive-type pattern. The obtained resist pattern was evaluated as follows.

[0602] The fabricated patterned mask blanks were observed using an overhead SEM (scanning electron microscope), and the optimal exposure (μC / cm²) was determined to resolve the 200nm 1:1 line and space (LS) pattern at a 1:1 ratio. 2 The critical resolution (resolution) was defined as the minimum dimension at the exposure dose that resolves 200nm LS at a 1:1 ratio, and the LER of 200nm LS was measured by SEM. For the critical resolution of isolated space (IS), the critical IS resolution was defined as the minimum dimension at the exposure dose that resolves 200nm 9:1 line and space (LS) at a 9:1 ratio.

[0603] Furthermore, the LS pattern with a line width of 18 nm and a pitch of 36 nm, formed with the optimal exposure amount, was inspected using a KLA2360 (product name) defect inspection device manufactured by KLA-Tencor. The pixel size of the defect inspection device was set to 0.16 μm and the threshold to 20, and defects (number of defects / cm²) were extracted from the differences resulting from the superposition of the comparison image and the pattern at the pixel level. 2 ) detects the number of defects per unit area (pieces / cm²). 2 The number of development defects per unit area (units / cm²) was calculated. Subsequently, a defect review was conducted to classify and extract development defects from all defects, and the number of development defects per unit area (units / cm²) was calculated. 2 The performance index (%) was calculated. Values ​​less than 0.5 were classified as A, values ​​between 0.5 and 1.0 as B, values ​​between 1.0 and 5.0 as C, and values ​​of 5.0 or higher as D. A smaller value indicates better performance. The results are shown in Tables 8-11.

[0604] [Table 8]

[0605] [Table 9]

[0606] [Table 10]

[0607] [Table 11]

[0608] The chemically amplified positive resist compositions (R-1 to R-90) of the present invention all exhibited good resolution and LER, and were confirmed to have few development defects. On the other hand, the comparative resist compositions (CR-1 to CR-60) had insufficient optimization of acid diffusion and contrast, resulting in degradation of resolution, LER, and development defects.

[0609] The resist pattern formation method using the chemically amplified positive resist composition of the present invention is useful for semiconductor device manufacturing, particularly for photolithography in the processing of transmissive and reflective photomask blanks.

Claims

1. (A) A base polymer containing repeating units represented by the following formula (A1), wherein the polymer's solubility in alkaline aqueous solutions increases with the action of an acid, and (B) Photoacid generator consisting of an onium salt represented by the following formula (B) A chemically amplified positive-type resist composition containing the following: 【Chemistry 1】 (In the formula, a1 is 0 or 1. When a1 is 0, a2 is 0, 1, 2 or 3, and when a1 is 1, a2 is 0, 1, 2, 3, 4 or 5.) R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 The bonds are single bonds, *-C(=O)-O-, or *-C(=O)-N(H)-. The asterisk (*) represents a bond with a carbon atom in the main chain. X 2 This refers to a single bond, an aliphatic hydrocarbylene group having 1 to 4 carbon atoms, a carbonyl group, a sulfonyl group, or a group obtained by combining these. X 3 and X 4 Each of these is independently either an oxygen atom or a sulfur atom. However, X 2 and X 4 It is bonded to the carbon atom adjacent to the aromatic ring. R 1 and R 2 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. Further, R 1 and R 2 may be bonded to each other to form a ring together with the carbon atoms to which they are bonded. R 3 This may include halogen atoms, hydroxyl groups, cyano groups, nitro groups, pentafluorosulfanyl groups, C1-C20 hydrocarbyl groups which may contain heteroatoms, C1-C20 hydrocarbyloxy groups which may contain heteroatoms, C2-C20 hydrocarbyloxycarbonyl groups which may contain heteroatoms, C1-C20 hydrocarbylthio groups which may contain heteroatoms, or -N(R) 3A )(R 3B ) is R 3A and R 3B Each is independently a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. When a2 is 2 or more, each R 3 They may be the same or different from each other, and there may be multiple R 3 These atoms may bond with each other to form a ring together with the carbon atoms of the aromatic ring to which they are bonded. 【Chemistry 2】 [In the formula, n1 is 0 or 1. n2 is 0, 1, 2, 3 or 4. n3 is 2, 3 or 4. However, when n1 is 0, 2 ≤ n2 + n3 ≤ 5, and when n1 is 1, 2 ≤ n2 + n3 ≤ 7. R 101 This is a C1-C20 hydrocarbyl group which may contain a halogen atom, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C1-C20 hydrocarbylthio group which may contain a heteroatom, or a C1-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. When n2 is 2, 3, or 4, each R 101 They may be the same or different from each other, and there may be multiple R 101 These atoms may bond with each other to form a ring with the carbon atoms to which they are bonded. Z + This is an onium cation. Ar AL is an acid-unstable group-containing group represented by the following formula (AL). However, at least one Ar AL is, -SO 3 - It is bonded to a carbon atom adjacent to the carbon atom to which it is bonded. 【Transformation 3】 (In the formula, n4 is 0 or 1. n5 is 0, 1, 2, 3 or 4. n6 is 0, 1, 2, 3 or 4. n7 is 1 or 2. However, when n4 is 0, 1 ≤ n5 + n6 + n7 ≤ 5, and when n4 is 1, 1 ≤ n5 + n6 + n7 ≤ 7.) R 102 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than fluorine, a nitro group, a cyano group, a hydroxyl group, a carboxyl group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, a C1-C20 hydrocarbylthio group which may contain a heteroatom, or a C1-C20 hydrocarbyloxycarbonyl group which may contain a heteroatom. When n5 is 2, 3, or 4, each R 2 They may be the same or different from each other, and there may be multiple R 2 These atoms may bond with each other to form a ring with the carbon atoms to which they are bonded. R F This is 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, a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms, or a pentafluorosulfanil group. When n6 is 2, 3, or 4, each R F They may be the same as or different from each other. R L1 and R L2 These are, independently, hydrocarbyl groups having 1 to 12 carbon atoms. L3 R is a hydrogen atom or a hydrocarbyl group having 1 to 12 carbon atoms. L1 , R L2 and R L3 The hydrocarbyl group represented by -CH 2 A portion of the - may be substituted with -O- or -S-, and if the hydrocarbyl group includes an aromatic ring or multiple bond, some or all of the hydrogen atoms bonded to the carbon atoms constituting the aromatic ring or multiple bond may be substituted with a halogen atom, a cyano group, a nitro group, a C1-C4 alkyl group which may contain a halogen atom, or a C1-C4 alkoxy group which may contain a halogen atom. Also, R L1 and R L2 However, they may bond to each other and form a ring with the carbon atoms to which they are bonded, and the -CH of the ring 2 A portion of the - may be replaced with -O- or -S-. However, R L3 If it does not contain any alicyclic structure, aromatic ring, or multiple bond, then R L1 and R L2 These atoms are bonded to each other, forming a ring with the carbon atoms to which they are bonded, and the -CH of this ring 2 Some of the hyphens may be replaced with -O- or -S-. * represents a bonding operation.

2. X 3 and X 4 The chemically amplified positive resist composition according to claim 1, wherein both are oxygen atoms.

3. X 2 The chemically amplified positive resist composition according to claim 1, wherein the carbonyl group is a carbonyl group.

4. The chemically amplified positive resist composition according to claim 1, wherein the photoacid generator is represented by the following formula (B1). 【Chemistry 4】 (In the formula, n1, n2, n3, n5, n6, n7, R 101 , R 102 , R F , R L1 ~R L3 and Z + (This is the same as above.)

5. The chemically amplified positive resist composition according to claim 4, wherein the photoacid generator is represented by the following formula (B2). 【Transformation 5】 (In the formula, n2, n3, n5, n6, n7, R 101 , R 102 , R F , R L1 ~R L3 and Z + (This is the same as above.)

6. Z + The chemically amplified positive resist composition according to claim 1, wherein the sulfonium cation represented by the following formula (Z-1) or the iodonium cation represented by the following formula (Z-2). 【Transformation 6】 (In the formula, R ct1 ~R ct5 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom. Also, R ct1 and R ct2 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded.

7. Z + The chemically amplified positive-type resist composition according to claim 1, wherein the sulfonium cation is represented by the following formula (Z-3). 【Transformation 7】 (In the formula, 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, It is either 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 Each of these is 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, 3, or 4, each R F1 They may be the same as or different from each other. When m6 is 2, 3, 4, 5 or 6, each R F2 They may be the same as or different from each other. When m7 is 2, 3, 4, 5 or 6, each R F3 They may be the same as or different from each other. R ct6 ~R ct9 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than iodine and fluorine atoms, a nitro group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, or a C1-C20 hydrocarbylthio group which may contain a heteroatom. When m8 is 2, two R ct6 The two Rs may be the same or different from each other. ct6 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When m9 is 2, two R ct7 The two Rs may be the same or different from each other. ct7 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When m10 is 2, two R ct8 The two Rs may be the same or different from each other. ct8 These may bond with each other to form a ring with the carbon atoms to which they are bonded. When m13 is 2, two R ct9 The two Rs may be the same or different from each other. ct9 These atoms may bond with each other to form a ring with the carbon atoms to which they are bonded. Furthermore, S in sulfonium cations + Aromatic rings that are directly bonded to each other are bonded to each other and form S + They may form a ring together. L A and L B These are, independently, a single bond, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. X L This is a hydrocarbylene group having 1 to 40 carbon atoms, which may contain single bonds or heteroatoms.

8. The chemically amplified positive resist composition according to claim 1, wherein the polymer further comprises repeating units represented by the following formula (A2). 【Transformation 8】 (In the formula, b1 is 0, 1, or 2; b2 is 1, 2, or 3; and b3 is an integer satisfying 0 ≤ b3 ≤ 5 + 2(b1) - b2.) R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y 1 The bonds are single bonds, *-C(=O)-O-, or *-C(=O)-N(H)-. The asterisk (*) represents a bond with a carbon atom in the main chain. R 11 This includes a halogen atom, a nitro group, a carboxyl group, a saturated hydrocarbyl group having 1 to 6 carbon atoms that may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms that may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms that 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 a part of -CH 2 - in said saturated hydrocarbylene group may be substituted with -O-.)

9. The chemically amplified positive resist composition according to claim 1, wherein the polymer comprises at least one selected from repeating units represented by the following formula (A3), repeating units represented by the following formula (A4), and repeating units represented by the following formula (A5). 【Chemistry 9】 (In the formula, c is 0, 1, 2, 3, 4, 5, or 6; d is 0, 1, 2, 3, or 4; e1 is 0 or 1; e2 is 0, 1, or 2; e3 is 0, 1, 2, 3, 4, or 5.) R A These are a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 21 and R 22 These are, independently, a hydroxyl group, a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms that may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms that may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms that may be substituted with a halogen atom. R 23 This group is 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, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, or a cyano group. When e3 is 1 or 2, it may also be a hydroxyl group. A 2 represents a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH 2 - in said saturated hydrocarbylene group may be substituted with -O-.)

10. The chemically amplified positive resist composition according to claim 1, wherein the polymer further comprises at least one selected from repeating units represented by the following formula (A6-1) and repeating units represented by the following formula (A6-2). 【Chemistry 10】 (In the formula, f1 is 0 or 1. f2 is 0, 1 or 2. f3 is an integer satisfying 0 ≤ f3 ≤ 5 + 2(f2) - f4. f4 is 1, 2 or 3. f5 is 0 or 1.) f11 is 0, 1, or 2. f12 is 0, 1, or 2. f13 is 0, 1, or 2. f14 is 0, 1, 2, 3, 4, or 5. R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. A 3 This is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the saturated hydrocarbylene group is -CH 2 Some of the hyphens may be replaced with -O-. A 4 This refers to a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-A 41 - is true. A 41 This is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms, which may contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring, or a phenylene group or a naphthylene group. * indicates a bond with a carbon atom of the main chain. R 31 This is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms that may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms that may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms that may be substituted with a halogen atom. R 32 and R 33 Each of these is independently a hydrocarbyl group having 1 to 10 carbon atoms, which may contain heteroatoms, and R 32 and R 33 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. R 34 Each of these is 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 35 Each of these is independently a hydrocarbyl group having 1 to 10 carbon atoms, which may contain heteroatoms. X is an acid-unstable group when f4 is 1, and when f4 is 2 or 3, it is a hydrogen atom or an acid-unstable group, but at least one of them is an acid-unstable group.

11. The chemically amplified positive resist composition according to claim 1, wherein the polymer comprises at least one selected from repeating units represented by the following formula (A7), repeating units represented by the following formula (A8), repeating units represented by the following formula (A9), repeating units represented by the following formula (A10), and repeating units represented by the following formula (A11). 【Chemistry 11】 (In the formula, g1 and g2 are independently 0, 1, 2, or 3. h1 is 0 or 1. h2 is 0, 1, 2, 3, or 4. h3 is 0, 1, 2, 3, or 4. However, when h1 is 0, 0 ≤ h2 + h3 ≤ 4, and when h1 is 1, 0 ≤ h2 + h3 ≤ 6.) R A These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z 1 This is a phenylene group which may have a single bond or a substituent. Z 2 This is a single bond, **-C(=O)-O-Z 21 -, **-C(=O)-N(H)-Z 21 - or ** - O - Z 21 - is Z 21 This is a divalent group obtained by combining an aliphatic hydrocarbylene group, a phenylene group, or a combination thereof, having 1 to 6 carbon atoms, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z 3 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, amide bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Z 4 This is a single bond, or a divalent group obtained by combining an aliphatic hydrocarbylene group, a phenylene group, or a combination thereof, and may contain a halogen atom, a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z 5 Each of these independently comprises a single bond, an optionally substituted phenylene group, an optionally substituted naphthylene group, and *-C(=O)-O-Z 51 - or * - C(=O) - N(R) - Z 51 - is Z 51 R is a C1-C10 aliphatic hydrocarbylene group, phenylene group, or naphthylene group, and the aliphatic hydrocarbylene group may contain a halogen atom, a hydroxyl group, an ether bond, an ester bond, or a lactone ring. R is a C1-C10 hydrocarbyl group which may contain a hydrogen atom or a heteroatom. Z 6 These are single bonds, ether bonds, ester bonds, sulfonic acid ester bonds, amide bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Z 7 Each of these is independently a single bond, ***-Z 71 -C(=O)-O-, ***-C(=O)-N(R)-Z 71 - or *** - O - Z 71 - is. is. Z 71 R is a hydroxylene group having 1 to 20 carbon atoms, which may contain heteroatoms. R is the same as described above. Z 8 These are, independently, single bonds, ****-Z 81 -C(=O)-O-, ****-C(=O)-N(R)-Z 81 - or ****-O-Z 81 - is Z 81 R is a hydroxylene group having 1 to 20 carbon atoms, which may contain heteroatoms. R is the same as described above. Z 9 This includes single bonds, methylene groups, ethylene groups, phenylene groups, fluorinated phenylene groups, trifluoromethyl groups, and *-C(=O)-O-Z. 91 -, *-C(=O)-N(R)-Z 91 - or * - O - Z 91 - is Z 91 R is a phenylene group substituted with an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. R is the same as described above. * represents a bond with a carbon atom in the main chain. ** represents Z 1 This represents a combination with Z. *** represents Z 6 This represents a combination with Z. **** is Z 7 This represents a combination of two things. L 1 These are single bonds, ether bonds, ester bonds, carbonyl groups, sulfonic acid ester bonds, sulfonamide bonds, carbonate bonds, or carbamate bonds. Rf 1 and Rf 2 Each of these is independently either a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 3 and Rf 4 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 5 and Rf 6 Each of these is independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. However, all Rf 5 and Rf 6 They cannot simultaneously become hydrogen atoms. Rf 7 is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, and is a fluorinated alkylthio group or pentafluorosulfanyl group having 1 to 6 carbon atoms. When h2 is 2, 3 or 4, each Rf 7 They may be the same as or different from each other. R 41 and R 42 Each of these is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms. Also, R 41 and R 42 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. R 43 This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than fluorine atoms, or heteroatoms. When h3 is 2, 3, or 4, each R 43 They may be the same or different from each other, and there may be multiple R 43 These atoms may bond with each other to form a ring with the carbon atoms to which they are bonded. M - It is a non-nucleophilic counterion. A + This is an onium cation.

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

13. Furthermore, the chemically amplified positive resist composition according to claim 1, further comprising (C) an organic solvent.

14. Furthermore, the chemically amplified positive resist composition according to claim 1, further comprising (D) a quencher.

15. The chemically amplified positive resist composition according to claim 1, further comprising a fluorine atom-containing polymer that includes at least one selected from the repeating units represented by the following formula (E1), the repeating units represented by the following formula (E2), the repeating units represented by the following formula (E3), and the repeating units represented by the following formula (E4), and which may further include at least one selected from the repeating units represented by the following formula (E5) and the repeating units represented by the following formula (E6). 【Chemistry 12】 (In the formula, j1 is 1, 2, or 3. j2 is an integer satisfying 0 ≤ j2 ≤ 5 + 2(j3) - j1. j3 is 0 or 1. k is 1, 2, or 3.) R B These are, independently, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R C Each of these is independently either a hydrogen atom or a methyl group. R 301 , R 302 , R 304 and R 305 Each of these is independently either a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R 303 , R 306 , R 307 and R 308 Each of these is independently a hydrogen atom, a C1-C15 hydrocarbyl group, a C1-C15 fluorinated hydrocarbyl group, or an acid-unstable group, R 303 , R 306 , R 307 and R 308 When the group is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be interposed between the carbon-carbon bonds. R 309 This is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms, which may have a hydrogen atom or a group containing a heteroatom between the carbon-carbon bonds. When j1 is 2 or 3, each R 309 They may be the same as or different from each other. R 310 This is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms, which may have a heteroatom interposed between the carbon-carbon bonds. When j2 is 2 or more, each R 310 They may be the same as or different from each other. R 311 This 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 the saturated hydrocarbyl group is -CH 2 A portion of the - may be substituted with an ester bond or an ether bond. W 1 This is a (k+1) valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1) valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. W 2 The bonds are single bonds, *-C(=O)-O-, or *-C(=O)-N(H)-. The asterisk (*) represents a bond with a carbon atom in the main chain. W 3 This is a single bond, -O-, *-C(=O)-O-W 31 -W 32 - or * - C(=O) - N(H) - W 31 -W 32 - is. W 31 This is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 A is a single bond, ester bond, ether bond, or sulfonamide bond. * indicates a bond to a carbon atom in the main chain.

16. Furthermore, the chemically amplified positive resist composition according to claim 1, further comprising a photoacid generator other than the onium salt represented by formula (B).

17. A method for forming a resist pattern, comprising the steps of: forming a resist film on a substrate using a chemically amplified positive-type resist composition according to any one of claims 1 to 16; irradiating the resist film with a pattern using a high-energy beam; and developing the resist film irradiated with the pattern using an alkaline developer.

18. The resist pattern formation method according to claim 17, wherein the high-energy beam is an extreme ultraviolet beam or an electron beam with a wavelength of 3 to 15 nm.

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

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

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