Method for forming patterns of radioactive linear components and resists

Abstract

The radiosensitive linear composition comprises: (A) a polymer containing the structural unit (U) represented by formula (1); and (B) a radiosensitive linear acid generator comprising an onium cation having at least one group Rf1 selected from the group consisting of fluoroalkyl and fluorine groups (excluding the fluorine group in the fluoroalkyl group), and an organic anion having an iodine atom. In formula (1), R1 is a hydrogen atom, methyl, etc. X1 is a single bond, ether bond, ester bond, etc. Ar1 is a cyclic group bonded to X1 by means of an aromatic ring. Wherein, the atoms of the atoms constituting the aromatic ring in Ar1 are bonded to the atoms adjacent to the atoms bonded to X1 by a hydroxyl group or -ORY group. RY is an acid dissociative group.

Description

Method for forming patterns of radioactive linear components and resists [Cross Reference to Related Applications] This application claims priority based on Japanese Patent Application No. 2022-024934, filed on February 21, 2022, the entire contents of which are incorporated herein by reference. This disclosure relates to a radiosensitive linear composition and a method for forming a resist pattern. In the lithography process used in the manufacturing of various electronic components such as semiconductor devices and liquid crystal devices, acid is generated in the exposed area by irradiating the radiosensitive linear component with far-ultraviolet light such as ArF excimer laser, extreme ultraviolet (EUV) light, electron beam, etc. The chemical reaction involving the generated acid creates a difference in the dissolution rate of the developer between the exposed and unexposed areas, thereby forming a resist pattern on the substrate. In the rapidly advancing miniaturization of various electronic component structures, there is a growing demand for further miniaturization of the resist pattern in the photolithography process. Furthermore, in response to this demand, various studies have been conducted to improve the resolution of chemically amplified radiosensitive linear compositions used in photolithography for microfabrication, or the rectangularity of the resist pattern (see, for example, Patent Document 1). Patent Document 1 discloses a chemically amplified resist composition comprising: an acid generator containing a triarylstrontium cation having one or more fluorine atoms; and a resin containing repeating units having phenolic hydroxyl groups. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Publication No. 2014-2359 [The problem that the invention aims to solve] In recent years, there has been a rapid advancement in the miniaturization of resist patterns, for example, attempts to form patterns with linewidths of less than 40 nm. Therefore, for radiosensitive linear compositions used in resist film formation, it is also required to form good resist patterns with minimal exposure when forming such fine resist patterns. Furthermore, even if the radiosensitive linear composition has high sensitivity, it may not be able to sufficiently suppress the diffusion of acid generated in the resist film due to exposure, potentially reducing the dimensional uniformity of the resist pattern. Therefore, radiosensitive linear compositions used in resist film formation also require good critical dimension uniformity (CDU) performance. During the developing process, insufficient contact between the developer and the resist film, or the adhesion of undissolved residue from the developer to the pattern surface, can sometimes lead to defects in the resulting resist film. These developing defects are more likely to occur with the miniaturization of the resist pattern. On the other hand, in order to obtain a well-shaped resist pattern while achieving the required dimensions, it is necessary to minimize the occurrence of developing defects. This disclosure was made in view of the aforementioned problems, and its purpose is to provide a method for forming a linear resist composition and resist pattern that can balance high sensitivity and CDU performance while suppressing the generation of development defects. [Means for Solving the Problems] According to this disclosure, the following means are provided. [1] A radiosensitive linear composition comprising: (A) a polymer comprising a structural unit (U) represented by formula (1); and (B) a radiosensitive linear acid generator comprising at least one Rf group selected from the group consisting of fluoroalkyl and fluorine groups (excluding fluorine groups in fluoroalkyl groups). 1 The onium cation and the organic anion containing an iodine atom. [Chem. 1] (In equation (1), R) 1 It can be a hydrogen atom, a fluorine group, a methyl group, or a trifluoromethyl group. X 1 It can be a single bond, ether bond, ester bond, or amide bond. Ar 1 To utilize aromatic rings and X 1 A ring-shaped base of bonding. Among them, Ar... 1 Among the atoms that form the aromatic ring, X 1 The atoms adjacent to the bonded atoms have hydroxyl groups or -OR bonds. Y Base. R Y (Acidic dissociative group) [2] A method for forming a resist pattern includes: forming a resist film on a substrate using a radiosensitive linear composition as described in [1]; exposing the resist film; and developing the exposed resist film. [Effects of the Invention] By using the radiosensitive linear composition and resist patterning method disclosed herein, resist patterns with good CDU performance and few development defects can be formed with less exposure. "Radiosensitive Linear Compositions" The radiosensitive linear composition disclosed herein (hereinafter, also referred to as "this composition") contains a hydroxyl group or -OR bonded to an aromatic ring. Y The polymer of specific structural units of the base (hereinafter also referred to as "(A) polymer") and the polymer composition of the radiosensitive linear acid generator. This composition comprises an onium salt of a radiosensitive onium cation and an organic anion that is the conjugate base of an acid, serving as a radiosensitive acid generator. The organic anion is typically an anion obtained by removing a proton from the acid group of an organic acid. In this radiosensitive acid generator, the radiosensitive onium cation decomposes under the influence of radiation, releasing the organic anion. The released organic anion then forms hydrogen bonds with components contained in the composition (e.g., the radiosensitive acid generator itself or the solvent), thereby generating an acid derived from the organic anion in the composition. The radiosensitive acid generator and the onium salt serving as the radiosensitive acid generator in this composition may be one or more. As a radiosensitive linear acid generator, this composition contains at least one Rf group selected from the group consisting of fluoroalkyl and fluorine groups (excluding the fluorine group in the fluoroalkyl group). 1 A radiosensitive linear acid generator (hereinafter also referred to as "(B) acid generator") consisting of onium cations and organic anions containing iodine atoms. Furthermore, the following may sometimes refer to the Rf group... 1 The onium cation is called a "specific cation", and the organic anion with an iodine atom is called a "specific anion". The acid generator (B) included in this composition may be a radiosensitive acid generator, an acid diffusion control agent, or both. Here, the acid generator is a component that, upon exposure, generates a strong acid in this composition that can cause the acid dissociation groups of the components in the radiosensitive composition to detach from their components. The acid diffusion control agent is a component that inhibits the diffusion of acid derived from the acid generator generated by exposure into the resist film and can suppress acid-induced chemical reactions in non-exposed areas. When this composition contains two or more onium salt compounds as radiosensitive acid generators, these onium salt compounds are classified as acid generators and acid diffusion control agents according to the relative strength of the acids. (B) The acid generator is preferably a compound that generates sulfonic acid, carboxylic acid, or sulfonamide in the composition upon exposure. Furthermore, the following will sometimes include terms with a base Rf 1 An acid-generating agent that combines an onionium cation with an organic anion containing an iodine atom is called a "(B-1) acid-generating agent," which contains an Rf group. 1 Acid diffusion control agents containing onium cations and organic anions with iodine atoms are called "(B-2) acid diffusion control agents". (B) Acid generators are compounds that are different from polymers (i.e., low molecular weight compounds) and do not have repeating units derived from monomers. As specific forms of this composition, the following forms <1> and <2> can be listed. <1> Form containing (A) polymer, (B-1) acid generating agent and (D) solvent. <2> Form containing (A) polymer, (B-2) acid diffusion control agent and (D) solvent. The radiosensitive linear composition in form <1> may further contain an acid diffusion control agent (B-2). In this case, the acid generator (B-1) is equivalent to a "first acid generator," and the acid diffusion control agent (B-2) is equivalent to a "second acid generator." Furthermore, the radiosensitive linear compositions in forms <1> and <2> may further contain other components besides those shown in each form. Examples of preferred components included in this composition include acid generators different from (B) acid generators (hereinafter also referred to as "(C) other acid generators"), and (E) high-fluorine polymers. Specific examples of (C) other acid generators include: compounds that produce an acid weaker than (B-1) acid generator in the composition upon exposure, and which are different from (B) acid generators (hereinafter also referred to as "other acid diffusion control agents" or "(C-2) acid diffusion control agents"); and compounds that produce an acid stronger than (B-2) acid diffusion control agents in the composition upon exposure, and which are different from (B) acid generators (hereinafter also referred to as "other acid generators" or "(C-1) acid generators"). When this composition contains (C) other acid generators, specific forms of this composition include the following <1-1> and <2-1> forms. <1-1> Form containing (A) polymer, (B-1) acid generator, (C-2) acid diffusion control agent, and (D) solvent. <2-1> Form containing (A) polymer, (B-2) acid diffusion control agent, (C-1) acid generator, and (D) solvent. The radiosensitive linear compositions in the forms of <1-1> and <2-1> exhibit better balance in terms of high sensitivity and improved CDU performance. The components constituting this composition and any arbitrarily blended components will be described in detail below. <(A) Polymer> (A) polymer comprises the structural unit (U) represented by the following formula (1). [Chemistry 2] (In equation (1), R) 1 It can be a hydrogen atom, a fluorine group, a methyl group, or a trifluoromethyl group. X 1 It can be a single bond, ether bond, ester bond, or amide bond. Ar 1 To utilize aromatic rings and X 1 A ring-shaped base of bonding. Among them, Ar... 1Among the atoms that form the aromatic ring, X 1 The atoms adjacent to the bonded atoms have hydroxyl groups or -OR bonds. Y Base. R Y (Acidic dissociative group) [Structural Unit (U)] In Equation (1), from the viewpoint of improving the copolymerization of the monoliths providing the structural unit (U), R 1 The group represented is preferably a hydrogen atom or a methyl group. X 1 Preferred to be a single bond, ether bond, or ester bond (-CO-O-), and more preferably a single bond or ester bond. Ar 1 It is a monovalent cyclic group with an aromatic ring structure. Here, "cyclic group" refers to a k-valent group obtained by removing k (k is an integer greater than or equal to 1) hydrogen atoms from the ring portion of the ring structure. The ring contained in the cyclic group may have substituents. As Ar 1 Aromatic rings in the form of hydrocarbons include: benzene rings, naphthalene rings, anthracene rings, and other aromatic hydrocarbon rings. Among these, benzene rings or naphthalene rings are preferred, and benzene rings are even more preferred. (The last sentence appears to be incomplete and possibly refers to a different context.) 1 The bonded aromatic ring can also form Ar by condensation with an aliphatic ring. 1 Part of the ring. At Ar 1 On the aromatic ring, at X 1 The adjacent positions of the atoms in a bond (hereinafter also referred to as "X") 1 (Adjacent position) with hydroxyl or -OR bonds Y base (R) Y (This is an acid-dissociative group, the same applies below). In other words, X 1 The bonded Ar 1 The carbon atom in the hydroxyl group or -OR Y Ar bonded by the base 1 The carbon atoms in it are directly bonded. For example, in Ar... 1 When the aromatic ring is a benzene ring, relative to X 1 And the hydroxyl group or -OR is bonded at the ortho position. Y Base. As -OR Y Bases, such as R, can be listed. Y These are tertiary hydrocarbon groups (e.g., tert-butoxy, 1-methylcyclopentyloxy, 1-methylcyclohexyloxy, etc.), acetal groups, etc. In terms of further improving the high sensitivity, CDU performance, and suppression of development defects of the radiosensitive linear composition, it can be introduced into X... 1 The substituent at the adjacent position is preferably a hydroxyl group. Furthermore, it is possible to [do something] with X 1 Ar of the bond 1 On the aromatic ring, at X 1 Substituents are further introduced at positions adjacent to each other. These substituents can be hydroxyl groups and -OR groups. Y One or both of the radicals can also be associated with hydroxyl and -OR. Y Different groups. (Regarding the interaction with hydroxyl and -OR groups) Y Different bases are introduced into Ar 1 In the case of an aromatic ring, specific examples of this group include: halogen atoms, monovalent hydrocarbon groups with 1 to 20 carbon atoms, alkyl carbonyl groups, alkyloxy carbonyl groups, carboxyl groups, cyano groups, and nitro groups, etc. (Regarding Ar...) 1 In the aromatic ring of X, 1 When substituents are further introduced at adjacent positions, the number of substituents is preferably four or less, and more preferably three or less. Preferably, the structural unit (U) is the structural unit represented by the following equation (1-1). [Chemistry 3] (In equation (1-1), R) 1 It can be a hydrogen atom, a fluorine group, a methyl group, or a trifluoromethyl group. X 1 It can be a single bond, ether bond, ester bond, or amide bond. R 2 It can be a hydrogen atom or an acid-dissociable radical. R 3 Halogen atom, hydroxyl group, -OR Y R, alkyl, alkylcarbonyl, alkyloxycarbonyl, carboxyl, cyano or nitro, or representing multiple R groups 3 Combined with multiple R 3 The condensed ring structure formed by the bonded benzene rings. R Y It is an acid-dissociable group. n is an integer from 0 to 4. When n is 2 or more, the multiple R groups in the formula... 3 (Same or different) In equation (1-1), -OR 2 Specific examples of the bases represented can be listed as -OR in equation (1). Y The same basis as the basis exemplified by the basis. As R 1 Better examples and R Y For specific examples, bases that are the same as those exemplified in equation (1) can be listed. As R 3 Examples of halogen atoms that can be represented include fluorine, chlorine, bromine, and iodine atoms. Among these, fluorine, bromine, or iodine atoms are preferred for their high EUV absorption efficiency, and fluorine or iodine atoms are even more preferred. As R 3 The alkyl group and R are represented 3 The alkyl groups represented by alkyl carbonyl groups and alkyloxy carbonyl groups can be listed as straight-chain or branched alkyl groups having 1 to 10 carbon atoms. 3 The alkyl group represented preferably has 1 to 6 carbon atoms, more preferably 1 to 3. 3 The alkyl moiety of the alkyl group, alkyl carbonyl group, and alkyloxy carbonyl group represented preferably has 1 to 6 carbon atoms, and more preferably 1 to 3 carbon atoms. At R 3 In the case of a monovalent substituent, R 3 The bonding position is not particularly limited. Specifically, R on the benzene ring in formula (1-1) 3 The bond position relative to X 1It can be any of the adjacent, intermediate, and opposite positions. n is preferably 0 to 2, more preferably 0 or 1, and even better if it is 0. As specific examples of structural units (U), structural units represented by the following formulas can be listed. [Chemistry 4] (where R) 1 It can be a hydrogen atom, a fluorine group, a methyl group, or a trifluoromethyl group. (t-Bu is a tertiary butyl group) The content of structural unit (U) in polymer (A) is preferably 10 mol% or more, more preferably 15 mol% or more, and even more preferably 20 mol% or more, relative to all structural units constituting polymer (A). Furthermore, the content of structural unit (U) is preferably 80 mol% or less, more preferably 70 mol% or less, and even more preferably 65 mol% or less, relative to all structural units constituting polymer (A). By setting the content of structural unit (U) within the aforementioned range, a resist film with good pattern shape can be obtained while suppressing development defects. [Other Structural Units] (A) The polymer may also have structural units different from structural unit (U) (hereinafter also referred to as "other structural units"). Examples of other structural units include structural units (I) to (V) shown below. Structural unit (I): Structural unit with an acid-dissociable group Structural unit (II): Structural unit with a hydroxyl group bonded to an aromatic ring (except for structural unit (U)) Structural unit (III): Structural unit with a radiosensitive linear ononium cation and an organic anion Structural unit (IV): Structural unit with a lactone structure, a cyclic carbonate structure, a sulfonyl lactone structure, or a ring structure composed of two or more of these Structural unit (V): Structural unit with an alcoholic hydroxyl group • Structural Unit (I) The acid-dissociative group in structural unit (I) is a group that substitutes for the hydrogen atoms of acid groups such as carboxyl or hydroxyl groups, and is a group that dissociates due to the action of acid. By including a polymer with acid-dissociative groups in this composition, the acid-dissociative groups dissociate to produce acid groups due to the acid generated by exposure, thereby changing the solubility of the polymer component in the developer. This imparts good photolithography properties (LWR (Line Width Roughness) or CDU performance, etc.) to this composition, and allows for the formation of good resist patterns. The structural unit (I) is not particularly limited as long as it has an acid-dissociable group. Examples of structural units (I) include the structural unit represented by the following formula (i-1) (hereinafter also referred to as "structural unit (I-1)") and the structural unit represented by the following formula (i-2) (hereinafter also referred to as "structural unit (I-2)"). [Chemistry 5] (In equation (i-1), R) 12 It can be a hydrogen atom, a fluorine group, a methyl group, or a trifluoromethyl group. L 1 It is a single bond, a substituted or unsubstituted phenyl group, or * 1 -CO-OR 10 -. R 10 It is a substituted or unsubstituted alkadiyl group having 1 to 6 carbon atoms, or a divalent group containing -O-, -CO-, or -COO- between the carbon-carbon bonds of an alkadiyl group having 2 to 6 carbon atoms. * 1 "Indicates to R" 12 The bonds formed by the carbon atoms. R 13 It is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R 14 and R 15 Each is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or represents R. 14 and R 15 Combine with R 14 and R 15 The bonded carbon atoms together form an alicyclic structure with 3 to 20 carbon atoms. R 13 R 14 and R 15 At least some of the hydrogen atoms may be substituted with halogen atoms or alkoxy groups. In formula (i-2), R 16 It can be a hydrogen atom, a fluorine group, a methyl group, or a trifluoromethyl group. L 2 It can be a single bond, ether bond, ester bond, or amide bond. R 17 R 18 and R 19 Each can be independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent oxygen hydrocarbon group having 1 to 20 carbon atoms. 17 R 18and R 19 (At least some of the hydrogen atoms may be substituted with halogen atoms or alkoxy groups) In equations (i-1) and (i-2), from the viewpoint of providing the copolymerization of the monolithic structural unit (I-1), R 12 Preferably, it is a hydrogen atom or a methyl group, more preferably a methyl group. From the viewpoint of providing copolymerization of the monotypic structural unit (I-2), R 16 Preferably, it is a hydrogen atom or a methyl group, and even more preferably, it is a hydrogen atom. At L 1 for* 1 -CO-OR 10 - In the case of R 10 Examples of alkyldiyl groups representing 1 to 6 carbon atoms include: methanediyl, 1,2-ethanediyl, 1,2-propanediyl, and 1,3-propanediyl. As L... 1 The substituents it contains can include halogen atoms, etc. L 2 Preferred to be a single bond, ester bond, or amide bond (-CO-NH-), more preferably a single bond or ester bond. As R 13 ~R 15 and R 17 ~R 19 Examples of monovalent hydrocarbon groups representing 1 to 20 carbon atoms include: monovalent chain hydrocarbon groups with 1 to 20 carbon atoms, monovalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms, and monovalent aromatic hydrocarbon groups with 6 to 20 carbon atoms. Examples of monovalent chain hydrocarbon groups with 1 to 20 carbon atoms include: alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, and pentyl; alkenyl groups such as vinyl, propynyl, butynyl, and pentynyl; and alkynyl groups such as ethynyl, propynyl, butynyl, and pentynyl. Examples of monovalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms include: monocyclic alicyclic saturated hydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; polycyclic alicyclic saturated hydrocarbon groups such as norbornyl, adamantyl, tricyclic decyl, and tetracyclic dodecyl; monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl; and polycyclic alicyclic saturated hydrocarbon groups such as norbornyl and tricyclic decenyl. Examples of monovalent aromatic hydrocarbon groups with 6 to 20 carbon atoms include: aryl groups such as phenyl, tolyl, xylyl, naphthyl, and anthracene; and aralkyl groups such as benzyl, phenethyl, naphthylmethyl, and anthracenemethyl. As R 14 and R 15 Combine with R 14 and R 15 Alicyclic structures with 3 to 20 carbon atoms formed by the bonded carbon atoms include: monocyclic alicyclic structures such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane; and polycyclic alicyclic structures such as norbornene, adamantane, tricyclic decane, and tetracyclic dodecane. As R 17 R 18 and R 19 The monovalent oxyalkyl groups representing carbon numbers from 1 to 20 can be listed as R. 13 ~R 15 and R 17 ~R 19 A monovalent hydrocarbon group having 1 to 20 carbon atoms, exemplified by groups whose bond side ends contain an oxygen atom (e.g., alkyloxy, cycloalkyloxy, aryloxy, etc.). R 17 R 18 and R 19 Preferably, these are chain hydrocarbon groups and cycloalkyloxy groups. As a specific example of a structural unit (I-1), one could list structural units represented by the following formula, etc. [Chemistry 6] [Chemistry 7] [Chemistry 8] (where R) 12(e.g., hydrogen atom, fluorine group, methyl group, or trifluoromethyl group) As a specific example of structural unit (I-2), the structural unit represented by the following formula can be listed, etc. [Chemistry 9] (where R) 16 (e.g., hydrogen atom, fluorine group, methyl group, or trifluoromethyl group) When polymer (A) includes structural unit (I), the content of structural unit (I) relative to all structural units constituting polymer (A) is preferably 20 mol% or more, more preferably 30 mol% or more, and even more preferably 35 mol% or more. Furthermore, the content of structural unit (I) relative to all structural units constituting polymer (A) is preferably 80 mol% or less, more preferably 70 mol% or less, and even more preferably 65 mol% or less. By setting the content of structural unit (I) within the aforementioned range, the difference in dissolution rate between the exposed and unexposed portions relative to the developer can be sufficiently increased, resulting in a better pattern shape for the resist film, which is preferable in this respect. • Structural Unit (II) Structural unit (II) is a structural unit having a hydroxyl group bonded to an aromatic ring and different from structural unit (U). Examples of aromatic rings with hydroxyl groups in structural unit (II) include benzene rings, naphthyl rings, anthracene rings, etc. Among these, benzene rings or naphthyl rings are preferred, and benzene rings are more preferred. The number of hydroxyl groups bonded to the aromatic ring in structural unit (II) is not particularly limited. The number of hydroxyl groups bonded to the aromatic ring in structural unit (II) is preferably one to three, more preferably one or two. Structural unit (II) can be exemplified by the structural unit represented by the following formula (ii). [Chemistry 10] (In equation (ii), R) 11 It can be a hydrogen atom, a fluorine group, a methyl group, or a trifluoromethyl group. L 3 It can be a single bond, ether bond, carbonyl bond, ester bond, or amide bond. 1 To utilize the aromatic ring with hydroxyl groups and L 3 A ring-shaped group of bonds. Among them, [the group] is related to L. 3 Y-bond 1 Among the atoms that form the aromatic ring, L 3 The atoms adjacent to the bonded atom have no hydroxyl groups or -OR bonds. Y Base. R Y (Acidic dissociative group) In equation (ii), from the viewpoint of providing the copolymerization of the monolithic structural unit (II), R 11 Preferably, it is a hydrogen atom or a methyl group. L 3 Single bonds or ester bonds are preferred. As specific examples of structural unit (II), structural units represented by the following formulas can be listed. [Chemistry 11] (where R) 11 (e.g., hydrogen atom, fluorine group, methyl group, or trifluoromethyl group) When the polymer (A) contains structural unit (II), the content of structural unit (II) is preferably less than that of structural unit (U). Specifically, relative to all structural units constituting the polymer (A), the content of structural unit (II) is preferably 25 mol% or less, more preferably 20 mol% or less, further preferably 10 mol% or less, and further preferably 5 mol% or less. By setting the content of structural unit (II) within the aforementioned range, development defects can be sufficiently suppressed while maintaining good lithography properties of the composition. • Structural Unit (III) Structural unit (III) is typically derived from a onium salt having a group that participates in polymerization (preferably a group containing a polymerizable carbon-carbon unsaturated bond). By having structural unit (III) in the polymer (A), the reduction effect of developer residue can be improved. Specific examples of structural unit (III) include the structural unit represented by equation (iii-1), the structural unit represented by equation (iii-2), and the structural unit represented by equation (iii-3). [Chemistry 12] (In equation (iii-1), R) 20 It can be a hydrogen atom or a methyl group. L 4 For a single bond, -O-, or -COO-. R 23 It is a substituted or unsubstituted alkyldiyl group having 1 to 6 carbons, a substituted or unsubstituted alkylenediyl group having 2 to 6 carbons, or a substituted or unsubstituted aryl group having 6 to 12 carbons. R 21 and R 22 Each is independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms. - It is an anion. In formula (iii-2), R 20 It can be a hydrogen atom or a methyl group. L 5 For single key, -R 30a -CO-O-、-R 30a -O- or -R 30a -O-CO-。 R 30a It is a substituted or unsubstituted divalent hydrocarbon group having 1 to 20 carbon atoms, or a divalent group containing -O-, -CO-, or -COO- between the carbon-carbon bonds of the hydrocarbon group. R 24 It is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a fluoroalkyl group having 1 to 10 carbon atoms. + It is an onium cation represented by formula (Y-1) or formula (Y-2) below. In formula (iii-3), R 20 It can be a hydrogen atom or a methyl group. L 6 It consists of a single bond, substituted or unsubstituted alkyldiyl groups having 1 to 6 carbon atoms, substituted or unsubstituted alkylenediyl groups having 2 to 6 carbon atoms, substituted or unsubstituted arylyl groups having 6 to 12 carbon atoms, and -CO-OR. 30b -、or -CO-NH-R 30b -. R 30b Y is a substituted or unsubstituted alkadiyl group having 1 to 6 carbon atoms, or a divalent group containing -O-, -CO-, or -COO- between carbon-carbon bonds in an alkadiyl group having 2 to 6 carbon atoms. + (The ononium cation represented by formula (Y-1) or formula (Y-2) below) [Chemistry 13] (In equations (Y-1) and (Y-2), R) 25 ~R 29 Each of the following is independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms. In equations (iii-1) to (iii-3), (Y-1) and (Y-2), in R 21 ~R 23 and R 25 ~R 29 When each group has a substituent, examples of substituents include: fluorine, chloro, bromo, iodo, alkoxy, cycloalkyloxy, ester, alkylsulfonyl, cycloalkylsulfonyl, hydroxy, carboxyl, cyano, nitro, acetyl, fluoroacetyl, etc. The cation in the formula is preferably a triarylstrontium cation or a diarylstrontium cation. As specific examples of structural unit (III), the structural units represented by equations (iii-1a) to (iii-10a) below can be listed. [Chemistry 14] (In equations (iii-1a) to (iii-10a), R) 20 It can be a hydrogen atom or a methyl group. Y + The onium cation represented by formula (Y-1) or formula (Y-2). M - (Anion) When polymer (A) contains structural unit (III), the content of structural unit (III) is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more, relative to all structural units constituting polymer (A). Furthermore, the content of structural unit (III) is preferably 40 mol% or less, more preferably 30 mol% or less, and even more preferably 20 mol% or less, relative to all structural units constituting polymer (A). By setting the content of structural unit (III) within the aforementioned range, the decrease in resolution accompanying acid diffusion can be suppressed, and the microstructure of this composition can be improved. • Structural unit (IV) Structural unit (IV) is a structural unit having at least one of the group consisting of lactone structures, cyclic carbonate structures, and sulfonyl lactone structures (excluding those equivalent to structural units (I) to (III)). By further including structural unit (IV) in the polymer (A), the solubility in the developer can be adjusted, and the adhesion between the resist film and the substrate obtained using this composition can be improved. As structural units (IVs), examples include structural units represented by the following formulas. [Chemistry 15] [Chemistry 16] [Chemistry 17] (where R) L1 (e.g., hydrogen atom, fluorine group, methyl group, or trifluoromethyl group) When polymer (A) has structural unit (IV), the content of structural unit (IV) is preferably 5 mol% or more, and more preferably 10 mol% or more, relative to all structural units constituting polymer (A). Furthermore, the content of structural unit (IV) is preferably 50 mol% or less, and more preferably 40 mol% or less, relative to all structural units constituting polymer (A). By setting the content of structural unit (IV) within the aforementioned range, the lithography properties of this composition and the adhesion between the resist film obtained using this composition and the substrate can be improved. • Structural Unit (V) Structural unit (V) is a structural unit having an alcoholic hydroxyl group (except for those corresponding to structural units (I) to (IV)). Here, "alcoholic hydroxyl group" as used in this specification refers to a group having a structure in which a hydroxyl group is directly bonded to an aliphatic hydrocarbon group. This aliphatic hydrocarbon group can be a chain hydrocarbon group or an alicyclic hydrocarbon group. By further including structural unit (V) in the polymer (A), the solubility in the developer can be improved, resulting in further improvement of the photolithography properties of this composition. Specific examples of monomers endowed with structural unit (V) include 3-hydroxyadamantane-1-yl methacrylate and 2-hydroxyethyl methacrylate. When polymer (A) has structural unit (V), the content of structural unit (V) is preferably 1 mol% or more, and more preferably 3 mol% or more, relative to all structural units constituting polymer (A). Furthermore, the content of structural unit (V) is preferably 30 mol% or less, and more preferably 15 mol% or less, relative to all structural units constituting polymer (A). As structural units of polymer (A), in addition to those listed above, examples include: structural units containing cyano, nitro, or sulfonamide groups (e.g., structural units derived from 2-cyanomethyladamantane-2-yl ester of (meth)acrylate, etc.); structural units containing halogen atoms (e.g., structural units derived from 2,2,2-trifluoroethyl ester of (meth)acrylate, structural units derived from 1,1,1,3,3,3-hexafluoropropane-2-yl ester of (meth)acrylate, structural units derived from 4-iodostyrene, etc.); and structural units containing non-acid-dissociable hydrocarbon groups (e.g., structural units derived from styrene, structural units derived from vinylnaphthalene, structural units derived from n-pentyl ester of (meth)acrylate, structural units derived from indene, etc.). The proportions of these structural units can be suitably set according to each structural unit without impairing the effects of this disclosure. (A) The polymer is preferably formulated into the composition as a component of the base resin constituting the composition. The proportion of (A) polymer in the composition is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, relative to the total amount of solid components contained in the composition. Furthermore, the proportion of (A) polymer is preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 95% by mass or less, relative to the total amount of solid components contained in the composition. By setting the proportion of (A) polymer relative to the total amount of solid components contained in the composition within the aforementioned range, a good resist pattern can be formed. Furthermore, the term "total amount of solid components" in this specification refers to the sum of components other than (D) solvent. (A) polymer may include only one type or may include two or more types. Furthermore, in addition to the polymer (A) containing structural unit (U), this composition may also contain a polymer containing at least one structural unit selected from the group consisting of structural units (I) to structural units (V) but not containing structural unit (U). From the viewpoint of obtaining a radiosensitive linear composition with excellent lithography properties or defect suppression, polymer (A) is preferably a polymer having both structural unit (U) and structural unit (I). Polymer (A) can be synthesized, for example, by using a free radical polymerization initiator or the like, to polymerize monomers providing each structural unit in a suitable solvent. In the case of obtaining a polymer containing a structural unit having a hydroxyl group bonded to an aromatic ring, polymerization can also be carried out with the phenolic hydroxyl group protected by a protecting group such as a base-dissociating group, followed by hydrolysis and deprotection, thereby introducing the structural unit into the polymer. (A) The weight-average molecular weight (Mw) of the polystyrene obtained by gel permeation chromatography (GPC) of the polymer is preferably 1,000 or more, more preferably 2,000 or more, further preferably 3,000 or more, and particularly preferably 5,000 or more. Furthermore, Mw is preferably 50,000 or less, more preferably 30,000 or less, further preferably 20,000 or less, and particularly preferably 10,000 or less. By setting the Mw of the polymer (A) within the aforementioned range, the coatability of the composition can be improved, and development defects can be sufficiently suppressed; these aspects are preferred. (A) The ratio of the polymer's Mw to the equivalent number average molecular weight (Mn) of the polystyrene obtained by GPC (Mw / Mn) is preferably 5.0 or less, more preferably 3.0 or less, and even more preferably 2.0 or less. In addition, Mw / Mn is generally 1 or more, and preferably 1.3 or more. <(B) Acid Generator> Next, the (B-1) acid generator and (B-2) acid diffusion control agent, which are specific forms of (B) acid generators, will be described. This composition may contain the (B-1) acid generator as a (B) acid generator, or it may contain the (B-2) acid diffusion control agent, or it may contain both. • (B-1) Acid generating agent (onium cation) The onium cation (specific cation) possessed by the (B-1) acid generating agent is any cation having one or more Rf groups. 1 Any radiosensitive linear onium cation is acceptable, with no particular limitation. Preferably, the cation has a strontium cation structure or a monium cation structure. Rf with fluoroalkyl group in a specific cation 1 In this case, the fluoroalkyl group can be either linear or branched. As a base Rf 1 The fluoroalkyl group preferably has 1 to 10 carbon atoms, and examples include: trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl, 2,2,3,3,3-pentafluoropropyl, 2,2,2-trifluoro-1-(trifluoromethyl)ethyl, perfluoron-propyl, perfluoroisopropyl, perfluoron-butyl, perfluoroisobutyl, perfluorotert-butyl, 2,2,3,3,4,4,5,5-octafluoropentyl, perfluorohexyl, etc. Among these, the group with 1 to 5 carbon atoms is preferred, more preferably trifluoromethyl, 2,2,2-trifluoroethyl, or perfluoroethyl, and even more preferably trifluoromethyl. From the perspective of sensitivity, the base Rf 1 Preferably, it is selected from at least one of the group consisting of fluorinated, trifluoromethyl, 2,2,2-trifluoroethyl and perfluoroethyl, and more preferably fluorinated or trifluoromethyl. In terms of further improving the CDU performance and sensitivity of this composition, the specific cation possesses the Rf group. 1 The quantity is preferably two or more, more preferably three or more. Furthermore, from the viewpoint of achieving a balance between improved sensitivity and ease of synthesis, the specific cation possesses a certain Rf group. 1 The quantity is preferably less than ten, more preferably less than eight, even better than seven, and even better than six. Furthermore, certain cations have fluoroalkyl groups as Rf. 1 In this case, the number of fluoroalkyl groups in a particular cation becomes the Rf group of that cation. 1The quantity. Therefore, for example, a particular cation has two trifluoromethyl (-CF) groups. In case 3), the specific cation possesses the group Rf 1 The quantity becomes two. Additionally, a fluorine group (-F) bonded to an aromatic ring and a trifluoromethyl group (-CF) are present in a specific cation. 3) In the case of two, the specific cation possesses the group Rf 1 The number becomes three. Rf in specific cations 1 The bonding position is not particularly limited. Regarding the improvement in sensitivity of this composition, the specific cation possesses a high degree of Rf... 1 One or more of the groups are preferably directly bonded to the aromatic ring contained in a specific cation, and more preferably two or more Rf groups. 1 Directly bonded to the aromatic ring. Furthermore, it has two or more Rf groups on a specific cation. 1 In the case of two or more base Rf 1 It can bond with the same aromatic ring of a specific cation, or it can bond with different aromatic rings. The specific cation is particularly preferably an aromatic ring (hereinafter also referred to as "aromatic ring Ar") bonded to one or more strontium or ferromonium cations. 2 」), base Rf 1 Directly bonded to the aromatic ring Ar 2 . As an aromatic ring Ar 2 Examples include: benzene rings, naphthalene rings, anthracene rings, etc. Among these, aromatic rings (Ar) 2 Preferably, it is a benzene ring or a naphthalene ring, with a benzene ring being particularly preferred. Among specific cations, for those with aromatic rings (Ar), 2 The base Rf of the bond 1 The total number can be calculated by applying the Rf group of a specific cation. 1 The quantity is specified. That is, with the aromatic ring Ar 2 The base Rf of the bond 1The total number is preferably two or more, more preferably three or more. Furthermore, from the viewpoint of achieving a balance between improved sensitivity and ease of synthesis, the aromatic ring Ar... 2 The base Rf of the bond 1 The total number is preferably less than ten, more preferably less than eight, further preferably less than seven, and even more preferably less than six. Regarding the aromatic ring Ar... 2 The base Rf of the bond 1 When the total number is more than two, the base Rf 1 It can bond with the same aromatic ring in a specific cation, or it can bond with different aromatic rings. From the viewpoint of sensitivity, the specific cation is preferably a triarylstrom cation or a diarylstrom cation. Specifically, the specific cation is preferably a cation represented by formula (2A) or a cation represented by formula (2B) below. [Chemistry 18] (In equation (2A), R) 1a R 2a and R 3a Each can be independently either fluoro or fluoroalkyl. R 4a and R 5a Each is a monovalent substituent, or represents R. 4a and R 5a Single or divalent groups that combine with each other and link the linked rings. R 6a Let R be a monovalent substituent. a1, a2, and a3 are independent integers from 0 to 5. Among them, a1 + a2 + a3 ≥ 1. a4, a5, and a6 are independent integers from 0 to 3. r is 0 or 1. Among them, a1 + a4 ≤ 5, a2 + a5 ≤ 5, and a3 + a6 ≤ 2 × r + 5. In equation (2B), R... 7a and R 8a Each can be independently either fluoro or fluoroalkyl. R 9a and R 10aEach a7 and a8 is an independent monovalent substituent. a7 and a8 are independent integers from 0 to 5, where a7 + a8 ≥ 1. a9 and a10 are independent integers from 0 to 3, where a7 + a9 ≤ 5 and a8 + a10 ≤ 5. In equations (2A) and (2B), R is used as... 1a R 2a R 3a R 7a and R 8a Specific examples and preferred examples of fluoroalkyl groups can be cited for those having a fluoroalkyl group as a radical in relation to a particular cation. 1 The same bases are shown in the description at that time. Among them, R 1a R 2a R 3a R 7a and R 8a Preferred components are fluoro, trifluoromethyl, 2,2,2-trifluoroethyl, or perfluoroethyl, with fluoro or trifluoromethyl being more preferred. By using onium salts having a structure in which a fluoro or trifluoromethyl group is directly bonded to an aromatic ring in a triarylstrontium cation structure or a diarylstrontium cation structure, the sensitivity of this composition can be further improved, and compositions with excellent CDU performance can be obtained. In equations (2A) and (2B), R 4a R 5a R 6a R 9a and R 10a The monovalent substituent represented is the nucleotide Rf group. 1 Different bases. As R 4a R 5a R 6a R 9a and R 10aSpecific examples of the monovalent substituent represented may include: a chlorine group, a bromine group, an iodine group, a substituted or unsubstituted alkyl group (wherein, a fluoroalkyl group is excluded), a substituted or unsubstituted alkoxy group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted cycloalkyloxy group, an ester group, an alkylsulfonyl group, a cycloalkylsulfonyl group, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, etc. Regarding R 4a 、R 5a 、R 6a 、R 9a 及R 10a For the alkyl group, alkoxy group, cycloalkyl group, and cycloalkyloxy group represented by R 4a 、R 5a 、R 6a 、R 9a 及R 10a When the alkyl group, alkoxy group, or cycloalkyl group in R 於R 4a 、R 5a 、R 6a 、R 9a 及R 10a is an ester group (-COOR), examples of the hydrocarbon moiety (R) of the ester group may include the exemplified substituted or unsubstituted alkyl group, or the substituted or unsubstituted cycloalkyl group. Regarding R 4a 、R 5a 、R 6a 、R 9a 及R 10aIn the case of an ester group, methoxycarbonyl, ethoxycarbonyl or n-butoxycarbonyl are preferred. At R 4a R 5a R 6a R 9a and R 10a In the case of an alkylsulfonyl group, the alkyl moiety constituting the alkylsulfonyl group can be exemplified by the substituted or unsubstituted alkyl groups described above. (Regarding R...) 4a R 5a R 6a R 9a and R 10a In the case of a cycloalkylsulfonyl group, the cyclic alkyl group constituting the cycloalkylsulfonyl group can be exemplified by the substituted or unsubstituted cycloalkyl groups. At R 4a and R 5a When referring to divalent bases that combine with each other and link the bonded rings, examples of such divalent bases include: -COO-, -OCO-, -CO-, -O-, -SO-, -SO-. 2-, -S-, alkyldiyl groups with 1 to 3 carbon atoms, alkenadiyl groups with 2 or 3 carbon atoms, and ethyl groups with -O-, -S-, -COO-, -OCO-, -CO-, -SO-, or -SO- at the carbon-carbon bond. 2-based. In R 4a and R 5a In the case of single bonds or divalent groups that combine with each other and link the linked loops, R 4a and R 5a It is preferable to form a single bond, -O- or -S-. The total number of a1, a2, and a3 is 1 or more, preferably 2 or more, even more preferably 3 to 10, and even more preferably 3 to 8. The total number of a7 and a8 is 1 or more, even more preferably 1 to 6. Specific examples of a particular cation include structures represented by the following formulas. However, the specific cation is not limited to the structures shown below. [Chemistry 19] [Chemistry 20] [Chemistry 21] [Chemistry 22] (Organic anions) Organic anions that can act as (B-1) acid generators (hereinafter also referred to as "specific anions AN1") include, for example, sulfonate anion structures, amide anion structures, methyl anion structures, carboxylate anion structures, etc. Among these, specific anion AN1 preferably has a sulfonate anion structure. The specific anion AN1 may have one or more iodine groups. From the viewpoint of achieving high sensitivity and improved CDU performance of this composition, the specific anion AN1 preferably has two or more iodine groups, more preferably three or more. Furthermore, from the viewpoint of achieving a balance between improving CDU performance and ease of synthesis, the specific anion AN1 preferably has ten or fewer iodine groups, more preferably eight or fewer. The bonding position of the iodine groups in the specific anion AN1 is not particularly limited. For the purpose of significantly improving the sensitivity of this composition, it is preferable that one or more iodine groups in the specific anion AN1 are directly bonded to an aromatic ring, and more preferably, two or more iodine groups are directly bonded to an aromatic ring. When the specific anion AN1 has two or more iodine groups, these two or more iodine groups may be bonded to the same aromatic ring in the specific anion AN1, or they may be bonded to different aromatic rings. The aromatic rings bonded to by the iodine groups are preferably benzene rings and naphthalene rings, and more preferably benzene rings. In a specific anion AN1, the total number of iodide groups bonded to the aromatic ring can be described by the number of iodide groups possessed by the specific anion AN1. That is, the total number of iodide groups bonded to the aromatic ring is preferably two or more, more preferably three or more. Furthermore, from the viewpoint of achieving a balance between improving CDU performance and ease of synthesis, the total number of iodide groups bonded to the aromatic ring is preferably ten or less, more preferably eight or less. Specific examples of the particular anion AN1 can be listed below, representing the anions represented by formulas (b-1) to (b-21). [Chemistry 23] [Chemistry 24] [Chemistry 25] In formulas (b-1) to (b-21), X is independently a hydrogen atom, a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen group. In each formula, one or more of the multiple X's are iodine atoms. R f It is a fluoroalkyl dimethyl group with 1 to 6 carbon atoms. 1 It consists of a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an oxecyclopropyl group, or an oxecyclobutyl group. T 2 It consists of hydrogen atoms or cycloalkyl groups. T 3 It can be a hydrogen atom or an alkyl group. T 4 It is 1,2-ethanediyl, 1,2-ethylenediyl, 1,2-acetylenediyl, cycloalkyldiyl, norbornenediyl, adamantanediyl, or phenylene. 70 It is an alkyldiyl or fluoroalkyldiyl group having 1 to 6 carbon atoms. R 71 Z represents a hydrogen atom or an alkyl group. Z represents a benzene ring or a cyclohexane ring. m represents 0 or 1. The monovalent organogroup represented by X, having 1 to 20 carbon atoms, is preferably a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, or -OR. k -COOR k -O-CO-R k -OR kk -COOR k or -R kk -CO-R k R k It is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R kk It is a single bond or a divalent hydrocarbon group with 1 to 10 carbon atoms. Specific examples of X being a monovalent hydrocarbon group having 1 to 20 carbon atoms include: linear or branched chain hydrocarbon groups having 1 to 20 carbon atoms, alicyclic hydrocarbon groups having 3 to 20 carbon atoms, and aromatic hydrocarbon groups having 6 to 20 carbon atoms. Substituents in X that replace the hydrogen atoms of the hydrocarbon group include: halogen groups, alkoxy groups, cycloalkyloxy groups, ester groups, alkylsulfonyl groups, cycloalkylsulfonyl groups, hydroxyl groups, carboxyl groups, cyano groups, nitro groups, and fluoroacetyl groups. As for R... kk Specific examples of divalent hydrocarbon groups with 1 to 10 carbon atoms include: linear or branched chain hydrocarbon groups with 1 to 10 carbon atoms, alicyclic hydrocarbon groups with 3 to 10 carbon atoms, and aromatic hydrocarbon groups with 6 to 10 carbon atoms. R f and R 70 The fluoroalkyl diesters representing 1 to 6 carbon atoms can be either linear or branched. R f and R 70 The fluoroalkyl diyl group representing 1 to 6 carbon atoms is preferably 1 to 4 carbon atoms. Specific examples include: -CF 2-、-CF 2-CF 2-、-CH(CF 3)-CF 2-、-CH 2-CF 2-、-CF 2-CH 2-、-C(CF 3) 2-CH 2-、-CH 2-C(CF 3) 2- etc. R 70 The alkyl dienes represented by R, having 1 to 6 carbon atoms, can be either straight-chain or branched. 70 The alkyldiyl group representing 1 to 6 carbon atoms is preferably 1 to 3 carbon atoms, and more preferably methylene or ethyl. R 71 The alkyl group represented can be either straight-chain or branched. R 71 The alkyl group represented is preferably 1 to 5 carbons, and more preferably methyl or ethyl. Specific examples of the particular anion AN1 include organic anions represented by the following formulas. However, the particular anion AN1 is not limited to the following structures. [Chemistry 26] [Chemistry 27] Specific examples of (B-1) acid-generating agents include onium salts comprising the specific cation and the specific anion AN1 as illustrated above. Further specific examples include: onium salts comprising the onium cation represented by formula (2A) and the organic anion represented by formulas (b-1) to (b-21); and onium salts comprising the onium cation represented by formula (2B) and the organic anion represented by formulas (b-1) to (b-21). When this composition includes an acid generating agent (B-1) as an acid generator (B), the content of the acid generating agent (B-1) in this composition is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, relative to 100 parts by mass of the polymer (A). Furthermore, the content of the acid generating agent (B-1) is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the polymer (A). By setting the content of the acid generating agent (B-1) within the aforementioned range, the sensitivity and CDU performance of this composition can be further improved. The acid generating agent (B-1) can be used alone or in combination of two or more. • (B-2) Acid diffusion control agent: By incorporating (B-2) acid diffusion control agent into this composition, the lithography properties (especially CDU performance) of this composition can be further improved. Furthermore, it can suppress linewidth variations in the resist pattern caused by changes in placement time from exposure to development, thereby obtaining a radiosensitive linear composition with excellent process stability. (B-2) The acid diffusion control agent is a photodegradable base, and is a compound that, upon exposure, produces an acid weaker than that produced by the acid generator incorporated into this composition. Specific examples of (B-2) acid diffusion control agents include compounds that produce carboxylic acids, sulfonic acids, or sulfonamides upon exposure. The degree of acidity can be evaluated by the acid dissociation constant (pKa). The acid dissociation constant of the acid produced by the photodegradable base is typically -3 or higher, preferably -1 ≤ pKa ≤ 7, and more preferably 0 ≤ pKa ≤ 5. (B-2) Acid diffusion control agents possess onium cations (specific cations) that have one or more Rf groups. 1 Any radiosensitive onium cation is acceptable, and there is no particular limitation. Preferably, the specific cation has a strontium cation structure or a monium cation structure. Specific examples of specific cations having a strontium cation structure include the onium cation represented by formula (2A), and specific examples of specific cations having a monium cation structure include the onium cation represented by formula (2B). Specific examples of the onium cations represented by formulas (2A) and (2B) are as described above. In terms of improving sensitivity while maintaining the CDU performance of this composition well, the specific cation possesses a base Rf... 1 The quantity is preferably two or more. For base Rf 1 The bonding positions can be described using the specific cations present in (B-1) acid generators. Organic anions (hereinafter also referred to as "specific anion AN2") that serve as diffusion control agents for (B-2) acids can be exemplified by, for example, sulfonate anion structures, amide anion structures, methyl anion structures, carboxylate anion structures, etc. Among these, the specific anion AN2 preferably has a sulfonate anion structure or a carboxylate anion structure, and more preferably has a carboxylate anion structure. By including an acid diffusion control agent comprising a specific cation and a specific anion AN2 in this composition, high sensitivity and improved CDU performance can be achieved. From the viewpoint of fully realizing improved sensitivity and CDU performance, the specific anion AN2 preferably has two or more iodine groups, more preferably three or more. Furthermore, from the viewpoint of balancing the improvement in CDU performance with ease of synthesis, the specific anion AN2 preferably has ten or fewer iodine groups, more preferably eight or fewer. The bonding position of the iodine group in the specific anion AN2 is not particularly limited. For the purpose of significantly improving the sensitivity of the composition, it is preferable that one or more iodine groups in the specific anion AN2 are directly bonded to the aromatic ring of the specific anion AN2, and more preferably that two or more iodine groups are directly bonded to the aromatic ring. When the specific anion AN2 has two or more iodine groups, these two or more iodine groups may be bonded to the same aromatic ring in the specific anion AN2, or they may be bonded to different aromatic rings. Specific examples and preferred examples of the aromatic ring bonded to the iodine group, as well as specific examples and preferred examples of the bonding position of the iodine atom, can be applied to the description of the specific anion AN1 in the (B-1) acid generating agent. Specific examples of the particular anion AN2 can be listed below, representing the anions represented by formulas (b2-1) to (b2-7). [Chemistry 28] In formulas (b2-1) to (b2-7), X is independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group with 1 to 3 carbon atoms, an amino group, or an amino group protected by an acid-dissociable group. In each formula, one or more of the multiple X's are iodine atoms. R ff It is an alkyldiyl group having 1 to 6 carbon atoms or a fluoroalkyldiyl group having 1 to 6 carbon atoms. R 73 It is a fluorinated divalent cyclic group. R 74 It is an alkyldiyl group having 1 to 6 carbon atoms. 5 (Alkyl or cycloalkyl) In equations (b2-1) to (b2-7), R is used as... ffThe fluoroalkyl dimethyl groups representing 1 to 6 carbon atoms can be listed as R in formulas (b-1) to (b-21). f The bases illustrated are the same as those in R. ff The alkyldiyl groups representing 1 to 6 carbon atoms can be listed as R in formulas (b-1) to (b-21). 70 The exemplified bases are the same bases. As R 73 The fluorinated divalent cyclic group can be exemplified by a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, in which one or more hydrogen atoms are substituted by fluorine atoms. Specific examples of alicyclic hydrocarbon groups and aromatic hydrocarbon groups can be listed as R... 13 ~R 15 and R 17 ~R 19 The groups represented are the same as those exemplified by monovalent hydrocarbon groups with 1 to 20 carbon atoms. Specific examples of the particular anion AN2 include organic anions represented by the following formulas. However, the particular anion AN2 is not limited to the following structures. [Chemistry 29] Specific examples of (B-2) acid diffusion control agents include onium salts comprising the specific cation and the specific anion AN2 as illustrated above. Further specific examples include: onium salts comprising the onium cation represented by formula (2A) and the organic anion represented by formulas (b2-1) to (b2-7); and onium salts comprising the onium cation represented by formula (2B) and the organic anion represented by formulas (b2-1) to (b2-7). When this composition includes a (B-2) acid diffusion control agent as an (B) acid generator, the content of the (B-2) acid diffusion control agent in this composition is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2.5 parts by mass or more, relative to 100 parts by mass of the (A) polymer. Furthermore, the content of the (B-2) acid diffusion control agent is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the (A) polymer. By setting the content of the (B-2) acid diffusion control agent within the aforementioned range, the sensitivity and CDU performance of this composition can be further improved. The (B-2) acid diffusion control agent can be used alone or in combination of two or more. <(C) Other Acid Generators> The specific forms of (C) other acid generators, namely (C-1) acid generators and (C-2) acid diffusion control agents, are described. • (C-1) Acid Generator: Onium salt compounds comprising radiosensitive onium cations and organic anions are preferably used as (C-1) acid generators. Specifically, the onium cation constituting the (C-1) acid generator has a radical Rf group. 1 In the case where the organic anion constituting the (C-1) acid generator does not have an iodine atom, and the onium cation constituting the (C-1) acid generator does not have an iodine atom, the organic anion constituting the (C-1) acid generator does not have an iodine atom. 1 Additionally, (C-1) acid generators can also be those containing no Rf group. 1 Onium salts are compounds of onium cations and organic anions that do not have iodine atoms. They can be used as (C-1) acid generators, either alone or in combination of two or more. From the viewpoint of improving the lithography properties of the composition, the onium cation, which is a (C-1) acid generator, is preferably a cation having a strontium cation structure or a monazine cation structure. Specific examples of these include the cation represented by formula (2A) or the cation represented by formula (2A) that satisfies a1+a2+a3=0, which has a strontium cation structure. Similarly, the cation represented by formula (2B) or the cation represented by formula (2B) that satisfies a7+a8=0, which has a monazine cation structure. (C-1) The organic anion possessed by the acid generating agent is not particularly limited. Specific examples of such organic anions include organic anions having a sulfonate anion structure, a amide anion structure, or a methylation anion structure. Among these, the organic anion having a sulfonate anion structure is preferred. Specific examples of the organic anion possessed by the (C-1) acid generating agent include the organic anion represented by the following formula (7). [Chemistry 30] (In equation (7), n1 is an integer from 0 to 10. n2 is an integer from 0 to 10. n3 is an integer from 1 to 10. n1+n2+n3 is greater than 1 and less than 30. When n1 is greater than 2, multiple R p2 Same or different. When n² is greater than 2, multiple R... p3 Same or different, multiple R p4Same or different. When n3 is 2 or more, multiple R... p5 Same or different. R p1 R is a monovalent basis containing ring structures with 5 or more ring members. p2 It is a divalent linkage base. R p3 and R p4 Each can be independently a hydrogen atom, a fluorine group, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R p5 For -CR p6 R p7 -or fluorophenyl. R p6 and R p7 Each is independently a hydrogen atom, a fluorine group, or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. Wherein, when n3 is 1, R p6 and R p7 Not all are hydrogen atoms; when n3 is 2 or higher, multiple R atoms... p6 and R p7 (Not all of them are hydrogen atoms) In equation (7), R is used as p1 The monovalent bases that represent ring structures with 5 or more ring members can be exemplified by, for example, alicyclic monovalent bases with 5 or more ring members, aliphatic heterocyclic monovalent bases with 5 or more ring members, aromatic hydrocarbon ring structures with 6 or more ring members, and aromatic heterocyclic monovalent bases with 5 or more ring members. Examples of alicyclic structures with five or more ring members include: monocyclic cycloalkanes such as cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, and cyclododecane; monocyclic cycloolefins such as cyclopentene, cyclohexene, cycloheptene, cyclooctene, and cyclodecene; polycyclic cycloalkanes such as norbornane, adamantane, tricyclic decane, and tetracyclic dodecane; and polycyclic cycloolefins such as norbornene and tricyclic decene. Examples of aliphatic heterocyclic structures with 5 or more ring members include: lactone structures such as hexanolactone and norbornane lactone; sulfonolactone structures such as hexanosultone and norbornane sulfonolactone; heterocyclic structures containing oxygen atoms such as oxacycloheptanane, oxanorbornane, and cyclic acetal; heterocyclic structures containing nitrogen atoms such as azircyclohexane and diazabicyclooctane; and heterocyclic structures containing sulfur atoms such as thiohexane and thionorbornane. Examples of aromatic hydrocarbon ring structures with 6 or more ring members include: benzene, naphthalene, phenanthrene, and anthracene. Examples of aromatic heterocyclic structures with 5 or more ring members include: oxygen-containing heterocyclic structures such as furan, pyran, and benzopyran; and nitrogen-containing heterocyclic structures such as pyridine, pyrimidine, and indole. Furthermore, R p1 The ring structure contains some or all of its hydrogen atoms, which may be substituted with substituents. Examples of substituents include: halogen groups, hydroxyl groups, carboxyl groups, cyano groups, nitro groups, alkoxy groups, alkoxycarbonyl groups, alkoxycarbonyloxy groups, acetyl groups, acetyloxy groups, etc. In this context, R... p1 The monovalent group represented is preferably an aromatic hydrocarbon ring structure with 6 or more ring members or an aromatic heterocyclic structure with 5 or more ring members, and is particularly preferably a group with a benzene structure. As R p2 Examples of divalent linkages include: carbonyl, ether, carbonyloxy, thioether, thiocarbonyl, sulfonyl, and divalent hydrocarbon groups. Among these, carbonyloxy, sulfonyl, alkyldiyl, or cycloalkyldiyl are preferred, more preferably carbonyloxy or cycloalkyldiyl, even more preferably carbonyloxy or norbornenediyl, and even more preferably carbonyloxy. As R p3 and R p4 The monovalent hydrocarbon group representing 1 to 20 carbon atoms can be exemplified by alkyl groups having 1 to 20 carbon atoms. As R p3 and R p4 The monovalent fluorinated hydrocarbon group representing 1 to 20 carbon atoms can be exemplified by fluorinated alkyl groups having 1 to 20 carbon atoms. R p3 and R p4 Preferably, it is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a fluoro group, or a fluoroalkyl group having 1 to 3 carbon atoms. As R p6 and R p7 The monovalent fluorinated hydrocarbon group representing 1 to 20 carbon atoms can be exemplified by fluoroalkyl groups having 1 to 20 carbon atoms. As R p6 and R p7 Preferably, it is fluoro-based or fluoroalkyl, more preferably fluoro-based or perfluoroalkyl, further preferably fluoro-based or trifluoromethyl, and especially preferably fluoro-based. When n3 is 1, it is preferably R. p6 and R p7 All are fluorine-based, or R p6 It is fluorine-based and R p7 It can be a hydrogen atom or a trifluoromethyl group. n1 is preferably 0-5, more preferably 0-3, further preferably 0-2, and especially preferably 0 or 1. n2 is preferably 0-5, more preferably 0-2, further preferably 0 or 1, and especially preferably 0. n3 is preferably 1-5, more preferably 1-3, and further preferably 1 or 2. By setting n3 within the aforementioned range, the strength of the acid generated from the (C-1) acid generator can be increased, thereby further improving the lithography properties and sensitivity of this composition. n1+n2+n3 is preferably 2 or more. Furthermore, n1+n2+n3 is preferably 10 or less, more preferably 5 or less. Specific examples of organic anions that constitute (C-1) acid generators include organic anions represented by the formulas below. Furthermore, the onium cations constituting (C-1) acid generators do not possess the radical Rf. 1 In this case, the organic anion constituting the (C-1) acid generating agent can also be a specific anion AN1. Specific examples of the specific anion AN1 can be groups identical to those exemplified as the specific anion AN1 constituting the (B-1) acid generating agent. However, the organic anion possessed by the (C-1) acid generating agent is not limited to these structures. [Chemistry 31] [Chemistry 32] Relative to 100 parts by mass of polymer (A), the proportion of the radiosensitive linear acid generator in this composition (i.e., the total amount of acid generator (B-1) and acid generator (C-1)) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more. Furthermore, relative to 100 parts by mass of polymer (A), the proportion of the radiosensitive linear acid generator is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less. By setting the proportion of the radiosensitive linear acid generator within the aforementioned range, the sensitivity and CDU performance of this composition can be further improved. • (C-2) Acid diffusion control agents: Examples of (C-2) acid diffusion control agents include nitrogen-containing compounds and photodegradable bases. Examples of nitrogen-containing compounds include: amine-containing compounds (alkylamines, aromatic amines, polyamines, etc.), amide-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and nitrogen-containing compounds with acid-dissociating groups. The photodegradable base (hereinafter also referred to as "(C-2) photodegradable base") used as an other acid diffusion control agent is preferably a compound that does not substantially dissociate the acid dissociative groups in the composition when heated at a temperature of 110°C for 1 minute by exposure to the acid generated by exposure. As a (C-2) photodegradable base, onium salt compounds comprising radiosensitive onium cations and organic anions are preferably used. Among them, the onium cation constituting the (C-2) photodegradable base has a radical Rf. 1 In the case where the organic anion constituting the (C-2) photodegradable base does not have an iodine atom, and the onium cation constituting the (C-2) photodegradable base does not have an iodine atom, the organic anion constituting the (C-2) photodegradable base does not have an iodine atom. 1 Additionally, (C-2) photodegradable bases can also include those without the Rf group. 1 Onium salts are compounds containing onium cations and organic anions that do not have iodine atoms. As (C-2) photodegradable bases, they can be used alone or in combination of two or more. From the viewpoint of maximizing the lithography properties of this composition, onium salts that generate carboxylic acids, sulfonic acids, or sulfonamides by exposure are preferred as (C-2) photodegradable bases. The acid dissociation constant of the acid generated by the photodegradable base is typically -3 or higher, preferably -1≦pKa≦7, and more preferably 0≦pKa≦5. As a specific example of a (C-2) photodegradable base, the onium salt compound represented by the following formula (9) can be listed. [Chem. 33] (In equation (9), E) - For "R" 51 -COO - "R" 52 -SO 2-N - -R 51 "or "R 51 -SO 3 - The organic anion represented by 'R'. 51 and R 52 Each is an independent monovalent organogroup having 1 to 30 carbon atoms. Among them, E... - For "R" 51 -SO 3 - In the case of organic anions represented by "", in the case of "SO 3 - "No fluorine atoms are bonded to the carbon atoms in the bonded structure." + It is a radiosensitive linear ononium cation. Wherein, E - It has an iodine atom and Z + (Except for cases containing fluorine atoms) In equation (9), R is used as 51 The monovalent organic groups representing 1 to 30 carbon atoms can be exemplified as: monovalent hydrocarbon groups with 1 to 30 carbon atoms; monovalent groups γ with 1 to 30 carbon atoms whose ends contain divalent heteroatoms between carbon-carbon bonds or on the bonding side of the hydrocarbon group; and monovalent groups in which at least one hydrogen atom of the hydrocarbon group or monovalent group γ is substituted by a monovalent heteroatom group, etc. Among them, R 51 The monovalent organic group represented by carbon number 1 to 30 is preferably a monovalent group having a substituted or unsubstituted aromatic ring. As R 52The monovalent organogroups representing 1 to 30 carbon atoms can include substituted or unsubstituted alkyl groups and substituted or unsubstituted cycloalkyl groups. Examples of substituents in substituted alkyl groups include fluoro groups. Examples of substituents in substituted cycloalkyl groups include alkyl groups with 1 to 10 carbon atoms, fluoro groups, iodo groups, etc. Z + The radiosensitive linear onium cations represented are preferably those with a strontium cation structure or a monium cation structure, and more preferably those with a triarylstrontium cation structure or a diarylmonium cation structure. (C-2) The organic anion in the photodegradable base preferably has a carboxylate anion structure or a sulfonate anion structure. Specific examples of such organic anions include those represented by the following formulas. Furthermore, the onium cation constituting the (C-2) acid diffusion control agent does not have a radical Rf. 1 In this case, the organic anion constituting the (C-2) acid diffusion control agent can also be a specific anion AN2. Specific examples of the specific anion AN2 can be groups identical to those exemplified as the specific anion AN2 constituting the (B-2) acid diffusion control agent. However, the organic anion possessed by the (C-2) photodegradable base is not limited to these structures. [Chemistry 34] Relative to 100 parts by mass of polymer (A), the content ratio of the acid diffusion control agent in this composition (i.e., the total amount of acid diffusion control agent (B-2) and acid diffusion control agent (C-2)) is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 1.5 parts by mass or more. Furthermore, relative to 100 parts by mass of polymer (A), the content ratio of the acid diffusion control agent is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less. By setting the content ratio of the acid diffusion control agent within the aforementioned range, the CDU performance of this composition can be further improved. <(D) Solvent> The solvent for (D) is not particularly limited as long as it is a solvent capable of dissolving or dispersing the polymer (A) and the acid generator (B), as well as any other components as needed. Examples of solvents for (D) include: alcohols, ethers, ketones, amides, esters, hydrocarbons, etc. Examples of alcohols include: aliphatic monools with 1 to 18 carbon atoms, such as 4-methyl-2-pentanol and n-hexanol; alicyclic monools with 3 to 18 carbon atoms, such as cyclohexanol; polyols with 2 to 18 carbon atoms, such as 1,2-propanediol; and polyol ethers with 3 to 19 carbon atoms, such as propylene glycol monomethyl ether. Examples of ethers include: dialkyl ethers such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisopentyl ether, dihexyl ether, and diheptyl ether; cyclic ethers such as tetrahydrofuran and tetrahydropyran; and ethers containing aromatic rings such as diphenyl ether and anisole. Examples of ketones include: acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl isobutyl ketone, 2-heptanone, ethyl n-butyl ketone, methyl n-hexyl ketone, diisobutyl ketone, trimethylnonanone, and other chain ketones; cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, and other cyclic ketones; 2,4-pentanedione, acetone-acetone, acetophenone, diacetone alcohol, etc. Examples of amides include: N,N'-dimethylimidazolidineone, N-methylpyrrolidone, and other cyclic amides; N-methylmethamide, N,N-dimethylmethamide, N,N-diethylmethamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionic acid, and other chain amides, etc. Examples of esters include: monocarboxylic acid esters such as n-butyl acetate and ethyl lactate; polyol carboxylic acid esters such as propylene glycol acetate; polyol partial ether carboxylic acid esters such as propylene glycol monomethyl ether acetate; polycarboxylic acid diesters such as diethyl oxalate; carbonates such as dimethyl carbonate and diethyl carbonate; and cyclic esters such as γ-butyrolactone. Examples of hydrocarbons include: aliphatic hydrocarbons with 5 to 12 carbon atoms such as n-pentane and n-hexane; and aromatic hydrocarbons with 6 to 16 carbon atoms such as toluene and xylene. As solvent (D), it is preferably at least one selected from the group consisting of esters and ketones, more preferably at least one selected from the group consisting of polyol partial ether carboxylic esters and cyclic ketones, and even more preferably one or more selected from propylene glycol monomethyl ether acetate, ethyl lactate and cyclohexanone. One or more solvents may be used as solvent (D). <(E) High Fluorine Polymer> The (E) high fluorine polymer (hereinafter also referred to as "(E) polymer") is a polymer with a fluorine atom mass content greater than that of the (A) polymer. The (E) polymer is contained in this composition, for example, as a water-repellent additive. There is no particular limitation as long as the fluorine atom content of polymer (E) is greater than that of polymer (A). From the viewpoint of sufficiently improving water repellency by segregating polymer (E) onto the resist film, the fluorine atom content of polymer (E) is preferably 1% by mass or more, more preferably 2% by mass or more, further preferably 4% by mass or more, and further preferably 7% by mass or more. Furthermore, the fluorine atom content of polymer (E) is preferably 60% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. Moreover, the fluorine atom content (by mass%) of the polymer can be determined by… 13 The structure of the polymer is determined by methods such as C-nuclear magnetic resonance (NMR) spectroscopy, and then the calculations are performed based on that structure. (E) The Mw obtained by GPC of the polymer is preferably 1,000 or more, more preferably 3,000 or more, and even more preferably 4,000 or more. Furthermore, the Mw of the polymer is preferably 50,000 or less, more preferably 30,000 or less, and even more preferably 20,000 or less. The molecular weight distribution (Mw / Mn) expressed by the ratio of Mn to Mw obtained by GPC of the polymer is generally 1 or more, preferably 1.2 or more. Furthermore, the Mw / Mn ratio is preferably 5 or less, and even more preferably 3 or less. When this composition contains polymer (E), the proportion of polymer (E) in this composition is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, relative to 100 parts by mass of polymer (A). Furthermore, the proportion of polymer (E) in this composition is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 7 parts by mass or less, relative to 100 parts by mass of polymer (A). Moreover, this composition may contain only one type of polymer (E), or it may contain a combination of two or more types. <Other Optional Components> This composition may also contain components different from those described in (A) the polymer, (B) the acid generator, (D) the solvent, and (E) the high-fluorine polymer (hereinafter also referred to as "other optional components"). Examples of other optional components include: surfactants, compounds containing alicyclic skeletons (e.g., 1-adamantanecarboxylic acid, 2-adamantaneone, deoxycholic acid tributyl ester, etc.), sensitizers, and pre-existing accelerators. The proportion of other optional components in this composition may be appropriately selected based on each component, within the range that does not impair the effects disclosed herein. "Method for manufacturing radiosensitive linear composition" This composition can be manufactured, for example, by mixing (A) polymer and (B) acid generator, and (D) solvent and (E) high fluorine content polymer as needed, in the required proportions, preferably by filtering the obtained mixture using a filter (e.g., a filter with a pore size of about 0.2 μm). The solid content concentration of this composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. Furthermore, the solid content concentration of this composition is preferably 50% by mass or less, more preferably 20% by mass or less, and even more preferably 5% by mass or less. By setting the solid content concentration of this composition within the aforementioned range, good coatability can be achieved, and a resist pattern with a good shape can be formed. The composition obtained in the manner described above can also be used as a composition for forming positive patterns using alkaline developing solutions, or as a composition for forming negative patterns using developing solutions containing organic solvents. The resist pattern forming method disclosed herein includes: a step of coating the composition onto one side of a substrate (hereinafter also referred to as the "coating step"); a step of exposing the resist film obtained by the coating step (hereinafter also referred to as the "exposure step"); and a step of developing the exposed resist film (hereinafter also referred to as the "development step"). Examples of patterns formed by the resist pattern forming method disclosed herein include line and space patterns, hole patterns, etc. In the resist pattern forming method disclosed herein, since the resist film is formed using the composition, a resist pattern with good sensitivity and low CDU can be formed. The steps are described below. [Coating Step] In the coating step, a resist film is formed on the substrate by coating this composition onto one side of the substrate. The substrate for forming the resist film can be any previously known material, such as silicon wafers, silicon dioxide, or aluminum-clad wafers. Alternatively, an organic or inorganic antireflective film (e.g., see Japanese Patent Publication No. 6-12452 or Japanese Patent Publication No. 59-93448) can be formed on the substrate. Coating methods for this composition include spin coating, cast coating, and roll coating. After coating, a pre-bake (PB) can be performed to allow the solvent in the coating to evaporate. The PB temperature is preferably 60°C to 140°C, more preferably 80°C to 130°C. The PB time is preferably 5 seconds to 600 seconds, more preferably 10 seconds to 300 seconds. The average thickness of the formed resist film is preferably 10 nm to 1,000 nm, and more preferably 20 nm to 500 nm. [Exposure Step] In the exposure step, the resist film obtained by the coating step is exposed. This exposure is performed by irradiating the resist film with radiation through a photomask, or, where appropriate, a liquid immersion medium such as water. The radiation, depending on the linewidth of the target pattern, can be, for example, electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), X-rays, and gamma rays; or charged particle beams such as electron beams and alpha rays. Among these, the radiation irradiating the resist film formed using this composition is preferably far ultraviolet light, EUV, or an electron beam; more preferably, it is ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), EUV, or an electron beam; even more preferably, it is ArF excimer laser light, EUV, or an electron beam; even more preferably, it is EUV or an electron beam; and most preferably, it is EUV. This composition is preferably used to form a resist pattern by EUV exposure. Preferably, post-exposure bake (PEB) is performed after the exposure. It is believed that through PEB, the acid generated by the acid-generating agent during exposure can promote the dissociation of acid-dissociating groups in the exposed portion of the resist film. This increases the difference in solubility of the developer between the exposed and unexposed portions. The PEB temperature is preferably 50°C to 180°C, more preferably 80°C to 130°C. The PEB time is preferably 5 seconds to 600 seconds, more preferably 10 seconds to 300 seconds. [Developing Step] In this step, the exposed resist film is developed. This forms the desired resist pattern. Generally, after development, the film is rinsed with a solution such as water or alcohol and then dried. The developing method in this step can be alkaline development or organic solvent development. In the case of alkaline development, the developing solution used for development may include, for example, an aqueous solution prepared by dissolving at least one of the following alkaline compounds: sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, 1,5-diazabicyclo-[4.3.0]-5-nonene. Of these, an aqueous solution of TMAH is preferred. In the case of organic solvent development, the developing solution may include one or more of various organic solvents (e.g., hydrocarbons, ethers, esters, ketones, alcohols, etc.). Specific examples of organic solvents used as developing solutions may include solvents listed as solvent (D) in the description of this composition. There are no particular limitations on the development method; any known method may be selected. [Example] The present disclosure will now be described in detail based on embodiments, but the present disclosure is not limited to the embodiments described below. The methods for measuring various physical properties are shown below. [Weight-average molecular weight (Mw) and number-average molecular weight (Mn)] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymer were determined by gel permeation chromatography (GPC) using Tosoh GPC columns (two "G2000HXL", one "G3000HXL", and one "G4000HXL") under the following conditions: Dissolution solution: tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd.); Flow rate: 1.0 mL / min; Sample concentration: 1.0% by mass; Sample injection volume: 100 μL; Column temperature: 40°C; Detector: differential refractometer; Standard material: monodisperse polystyrene. The following shows the structures of the radiosensitive linear acid generators (PAG1~PAG9 and PAGc1~PAGc4), acid diffusion control agents (Q-1~Q-7, Qc-1~Qc-6 and X-1), and high fluorine content resin (F-1) used in the preparation of the radiosensitive linear resin composition. [Radiosensitive linear acid generator (PAG)] [Chem. 35] [Chemistry 36] [Acid diffusion control agent] [Chemical 37] [Chemistry 38] [High Fluorine Content Resin] F-1: Mw=8,900, Mw / Mn=2.0 [Chemical 39] [Synthesis of the Basic Resin] The monomers were combined and copolymerized in tetrahydrofuran (THF) solvent. Crystallization was performed in methanol, followed by repeated washing with hexane, separation, and drying. Polymers (P-1) to (P-13) and polymers (Pc-1) to (Pc-7) were obtained as polymers with the following composition (molbie) (designated as the "basic resin"). Furthermore, by... 1 The composition of the obtained base resin was confirmed by ¹H-NMR. In addition, the Mw and dispersity (Mw / Mn) of the obtained base resin were confirmed by GPC (solvent: THF, standard: polystyrene). 1H-NMR analysis was performed using a nuclear magnetic resonance apparatus (JNM-ECZS400 from NEC Corporation). P-1: Mw=8,400, Mw / Mn=1.7 P-2: Mw=7,600, Mw / Mn=1.6 P-3: Mw=8,100, Mw / Mn=1.7 P-4: Mw=9,800, Mw / Mn=1.7 P-5: Mw=9,700, Mw / Mn=1.6 P-6: Mw=9,100, Mw / Mn=1.8 P-7: Mw=8,200, Mw / Mn=1.8 P-8: Mw=8,100, Mw / Mn=1.7 P-9: Mw=8,300, Mw / Mn=1.7 P-10: Mw=8,200, Mw / Mn=1.7 P-11: Mw=9,000, Mw / Mn=1.6 P-12: Mw=8,700, Mw / Mn=1.6 P-13: Mw=9,000, Mw / Mn=1.7 Pc-1: Mw=8,600, Mw / Mn=1.7 Pc-2: Mw=7,800, Mw / Mn=1.6 Pc-3: Mw=8,300, Mw / Mn=1.7 Pc-4: Mw=9,900, Mw / Mn=1.7 Pc-5: Mw=9,800, Mw / Mn=1.6 Pc-6: Mw=9,200, Mw / Mn=1.8 Pc-7: Mw=8,300, Mw / Mn=1.8 (Composition of the base resin (values ​​are in molar ratios)) [Chem. 40] [Chemistry 41] [Chemistry 42] [Chemistry 43] [Examples 1-13, Comparative Examples 1-9] 1. Preparation of the radiosensitive linear resin composition: The components were dissolved in a solvent containing 100 ppm of FC-4430 manufactured by 3M as a surfactant, according to the composition shown in Table 1. The obtained solution was filtered using a 0.2 μm membrane filter to prepare the radiosensitive linear resin composition. 2. Evaluation of EUV Exposure Sensitivity: Using a spin coater (Tokyo Electron's "CLEAN TRACK ACT12"), a base film forming composition (Brewer Science's "ARC66") was applied to a 12-inch silicon wafer and heated at 205°C for 60 seconds to form a base film with an average thickness of 105 nm. Using the same spin coater, the various radiosensitive linear resin compositions shown in Table 1 were applied to this base film and heated at 130°C for 60 seconds (PB). Afterward, the wafer was cooled at 23°C for 30 seconds to form a resist film with an average thickness of 55 nm. This resist film was exposed using an EUV scanner (ASML's "NXE3300" (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask with a 46 nm pitch hole pattern on the wafer with +20% tolerance)). PEB was applied for 60 seconds on a heated plate at 120°C, followed by 30 seconds of development using a 2.38% (w / w) tetramethylammonium hydroxide (TMAH) aqueous solution, thereby forming a resist pattern with 23 nm apertures and a 46 nm spacing. The exposure value for forming this resist pattern with 23 nm apertures and a 46 nm spacing was set as the optimal exposure value (Eop), and the optimal exposure value was set as the sensitivity (mJ / cm). 2 The smaller the sensitivity value, the higher the sensitivity, and thus the better. The results are shown in Table 1. 3. Evaluation of CDU Performance: The Eop (Effect Opportunity) was irradiated with the same amount as described in step 2 to form a resist pattern with 23 nm apertures and a 46 nm spacing. The resist pattern was observed from above using a scanning electron microscope (Hitachi High-Technologies CG-5000). The aperture diameter was measured at 16 points within a 500 nm diameter range, and the average value was calculated. This process was repeated to measure the average value of a total of 500 points at any given point. The 3-sigma value was calculated based on the distribution of the measured values, and this 3-sigma value was set as the evaluation value (nm) for CDU performance. Regarding CDU performance, a smaller evaluation value indicates smaller aperture deviation over a long period, which is considered better. The results are shown in Table 1. 4. Evaluation of Development Defects: Using a spin coater (Tokyo Electron's "CLEAN TRACK ACT12"), a base film forming composition (Brewer Science's "ARC66") was coated onto a 12-inch silicon wafer and heated at 205°C for 60 seconds to form a base film with an average thickness of 105 nm. Using the same spin coater, the various radiosensitive linear resin compositions shown in Table 1 were coated onto this base film and subjected to a photopolymerization process (PB) at 130°C for 60 seconds. Afterward, the film was cooled at 23°C for 30 seconds to form a resist film with an average thickness of 55 nm. Next, the resist film was exposed using an EUV exposure apparatus (ASML's "NXE3300") with NA=0.33, illumination conditions: Conventional s=0.89, and mask: imecDEFECT32FFR02. After exposure, a photopolymerization process (PEB) was performed at 120°C for 60 seconds. The resist film was then alkaline developed using a 2.38% by mass TMAH aqueous solution as the alkaline developer. After development, the film was rinsed with water and then dried to form a positive resist pattern (32 nm lines and spatial patterns), which was then used as a wafer for defect inspection. The number of defects on the wafer was measured using a defect inspection device (KLA-Tencor's "KLA2810"). Regarding the number of defects after development, a defect rating of "A" was given if the number of defects determined to originate from the resist film was 15 or less, "B" was given if the number was more than 15 but less than 40, and "C" was given if the number was more than 40. The results are shown in Table 1. [Table 1] The solvents listed in Table 1 are detailed below: PGMEA (propylene glycol monomethyl ether acetate), GBL (gamma-butyrolactone), CHN (cyclohexanone), PGME (propylene glycol monomethyl ether), DAA (diacetone alcohol), EL (ethyl lactate). The resist patterns formed by EUV exposure were evaluated, and the results showed that the radiosensitive linear resin compositions of Examples 1 to 13 exhibited high sensitivity, good CDU performance, and few development defects. Specifically, when comparing the Rf groups in the acid generator and acid diffusion control agent, the results showed that... 1When the number of iodine atoms in Examples 1 and Comparative Examples 1, 2 and Comparative Examples 2, 3 and Comparative Examples 3, 4 and Comparative Examples 4, 5 and Comparative Examples 5, 6 and Comparative Examples 8 is the same as the number of iodine atoms, Examples 1 to 6, in which the base resin has structural units (U), show good results in maintaining good sensitivity and CDU performance and having fewer development defects compared to the corresponding comparative examples. Furthermore, in the absence of structural units containing phenolic hydroxyl groups at the meta or para positions, there is a tendency for a higher suppression effect on development defects compared to the cases containing such structural units (Examples 1 to 3, Examples 5 to 7). By using the described radiosensitive linear resin composition and resist patterning method, resist patterns with good sensitivity to exposure light, excellent CDU performance, and suppressed development defects can be formed. Therefore, these are preferably used in the processing of semiconductor devices that are expected to be further miniaturized in the future. none none

Claims

1. A radiosensitive linear composition comprising: (A) a polymer containing a structural unit (U) represented by formula (1); and (B) a radiosensitive linear acid generator comprising a fluoroalkyl group and a fluorine group (wherein, At least one onium cation of Rf1 from the group consisting of (excluding fluorine groups in fluoroalkyl groups) and an organic anion having an iodine atom, in formula (1), R1 is a hydrogen atom, fluorine group, methyl or trifluoromethyl; X1 is a single bond, ether bond, ester bond or amide bond; Ar1 ​​is a cyclic group bonded to X1 by means of an aromatic ring; wherein, in the atom constituting the aromatic ring in Ar1, the atom adjacent to the atom bonded to X1 is bonded with a hydroxyl group or -ORY group; RY is an acid-dissociable group.

2. The radiosensitive linear composition as claimed in claim 1, wherein the structural unit (U) is represented by the following formula (1-1), in which R1 is a hydrogen atom, a fluorine group, a methyl group, or a trifluoromethyl group; X1 is a single bond, an ether bond, an ester bond, or a amide bond; R2 is a hydrogen atom or an acid-dissociable group; R3 is a halogen atom, a hydroxyl group, an -ORY group, an alkyl group, an alkyl carbonyl group, an alkyloxy carbonyl group, a carboxyl group, a cyano group, or a nitro group, or represents a condensed ring structure formed by multiple R3s bonded together with a benzene ring bonded to multiple R3s; RY is an acid-dissociable group; n is an integer from 0 to 4; when n is 2 or more, the multiple R3s in the formula may be the same or different.

3. The radiosensitive linear composition as claimed in claim 1, wherein the (B) radiosensitive linear acid generator is a compound that generates sulfonic acid, carboxylic acid or sulfonamide in the composition by exposure.

4. The radiosensitive linear composition as claimed in claim 1, wherein the organic anion has a structure in which an iodine atom is bonded to an aromatic ring.

5. The radiosensitive linear composition as claimed in claim 1, wherein the onium cation has a strontium cation structure or a monium cation structure.

6. The radiosensitive linear composition as claimed in claim 1, wherein the onium cation has a structure containing an aromatic ring Ar2 bonded to a strontium cation or a monium cation and wherein the base Rf1 is bonded to the aromatic ring Ar2.

7. The radiosensitive linear composition as claimed in claim 1, wherein the organic anion has a structure in which an iodine atom is bonded to an aromatic ring, and the onium cation has a structure containing an aromatic ring Ar2 bonded to a strontium cation or a monium cation, and wherein the base Rf1 is bonded to the aromatic ring Ar2.

8. The radiosensitive linear composition as claimed in claim 1, wherein the (A) polymer comprises structural units having acid-dissociable groups.

9. The radiosensitive linear composition as claimed in claim 1, used to form a resist pattern by exposure to extreme ultraviolet light.

10. The radiosensitive linear composition as claimed in claim 1, further comprising a compound that, upon exposure, produces an acid in the composition that is weaker than that of the radiosensitive linear acid generator of (B), and is different from that of the radiosensitive linear acid generator of (B).

11. The radiosensitive linear composition as claimed in claim 1, further comprising a compound that, upon exposure, produces an acid in the composition that is stronger than that of the radiosensitive linear acid generator of (B), and is different from that of the radiosensitive linear acid generator of (B).

12. The radiosensitive linear composition as claimed in claim 1, comprising a first acid generator and a second acid generator that generates an acid weaker than the first acid generator in the composition as the (B) radiosensitive linear acid generator.

13. A method for forming a resist pattern, comprising: The step of forming a resist film on a substrate using the radiosensitive linear composition as described in any one of claims 1 to 12; The step of exposing the resist film; The step of developing the exposed resist film.

14. The resist patterning method as described in claim 13, wherein the resist film is exposed to extreme ultraviolet light.