Radiation-sensitive linear resin composition, patterning method and onium salt compound

Abstract

This invention provides a radiosensitive linear resin composition, a patterning method, and an onium salt compound that can fully utilize sensitivity or linewidth roughness performance and critical size uniformity performance. The invention relates to a radiosensitive linear resin composition comprising an onium salt compound represented by formula (1), a resin containing structural units having acid-dissociable groups, and a solvent. (In the formula (1), R1 is a monovalent hydrocarbon group with 1 to 20 carbon atoms; R2 and R3 are each independently a monovalent hydrocarbon group with 1 to 20 carbon atoms, or represent a ring structure with 3 to 20 ring members formed by R2 and R3 combined with the carbon atoms they are bonded to; R4 is a hydrogen atom or a monovalent hydrocarbon group with 1 to 20 carbon atoms and L1 is a substituted or unsubstituted divalent linker group with 1 to 40 carbon atoms, or represent a heterocyclic structure with 3 to 20 ring members formed by R4 and L1 combined with the nitrogen atoms they are bonded to; L2 is a single bond or a substituted or unsubstituted divalent linker group with 1 to 40 carbon atoms; Rf1 and Rf2 are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group with 1 to 10 carbon atoms, or a monovalent fluorinated hydrocarbon group with 1 to 10 carbon atoms; when there are multiple Rf1 and Rf2, multiple Rf1 and Rf2 are each independent of the other.) f2 may be identical or different; n is an integer from 1 to 4; Z+ is a monovalent radioactive linear onium cation.

Description

Technical Field

[0001] This invention relates to a radiosensitive linear resin composition, a patterning method, and an onium salt compound. Prior Technology

[0002] Photolithography, using photoresist compositions, is employed in the formation of fine circuits for semiconductor devices. A representative procedure involves, for example, generating acid by exposing a photoresist composition film to a dielectric mask pattern using radiation. The acid acts as a catalyst, creating a difference in solubility of the resin relative to an alkaline or organic developer between the exposed and unexposed areas, thereby forming a photoresist pattern on the substrate.

[0003] In the aforementioned photolithography technique, short-wavelength radiation such as ArF excimer lasers, or liquid immersion lithography, which involves exposing the image in a state where the space between the lens and the resist film of the exposure device is filled with a liquid medium, is used to advance pattern miniaturization.

[0004] In efforts to advance further technological advancements, the following technique has been proposed: a quencher (diffusion control agent) is incorporated into the resist composition to capture acid diffusing to unexposed areas via a salt exchange reaction, thereby improving the lithography performance based on ArF exposure (Patent Document 1). Furthermore, as a next-generation technology, lithography using shorter wavelength radiation such as electron beams, X-rays, and extreme ultraviolet (EUV) is also under investigation. [Existing technical documents] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent No. 5525968 Summary of the Invention

[0006] [The problem that the invention aims to solve]

[0007] In efforts toward this next-generation technology, it is required that the performance of the resist be equal to or better than that of the previous resists in terms of sensitivity or line width roughness (LWR), which represents the deviation of the line width of the resist pattern, and critical dimension uniformity (CDU), which is an indicator of the uniformity of line width or aperture.

[0008] The purpose of this invention is to provide a radiosensitive linear resin composition, a patterning method, and an onium salt compound that can fully exert the sensitivity or LWR performance and CDU performance. [Methods for solving problems]

[0009] The inventors have repeatedly studied and researched to solve this problem, and as a result, they have found that the above-mentioned objective can be achieved by adopting the following configuration, thus completing the present invention.

[0010] That is, in one embodiment of the present invention, there is a radiosensitive linear resin composition comprising: The onium salt compound represented by the following formula (1) (hereinafter also referred to as "onium salt compound (1)") Resins containing structural units with acid-dissociable groups, and Solvent. [Chemistry 1] (in the above formula (1), R1 is a monovalent hydrocarbon group with 1 to 20 carbon atoms; R2 and R3 are each independently a monovalent hydrocarbon group with 1 to 20 carbon atoms, or represent a ring structure with 3 to 20 ring members formed by the combination of R2 and R3 together with the bonded carbon atoms; R4 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and L1 is a substituted or unsubstituted divalent linker having 1 to 40 carbon atoms, or represents a group containing a heterocyclic structure with 3 to 20 ring members, consisting of R4 and L1 bonded together with the nitrogen atoms bonded thereto; L2 is a single bond or a substituted or unsubstituted divalent linker with 1 to 40 carbon atoms; Rf1 and Rf2 are independently hydrogen atoms, fluorine atoms, monovalent hydrocarbon groups with 1 to 10 carbon atoms, or monovalent fluorinated hydrocarbon groups with 1 to 10 carbon atoms; when multiple Rf1 and Rf2 exist, the multiple Rf1 and Rf2 may be the same or different from each other; n is an integer from 1 to 4; Z+ is a monovalent radiosensitive linear onium cation.

[0011] This radiosensitive linear resin composition exhibits excellent sensitivity, LWR performance, and CDU performance when forming resist patterns. The rationale for this is based on speculation, though not bound by any theoretical constraints. It is speculated that the onium salt compound (1) in the radiosensitive linear composition functions as a quencher (acid diffusion control agent). In the exposed section, it is believed that the acid generated by the onium salt compound (1) or other radiosensitive linear acid generators through exposure causes the tertiary alkoxy carbonyl group protecting the nitrogen atom within the onium salt compound (1) molecule to deprotect, forming an intramolecular salt in which sulfonate anions and ammonium cations coexist, thus becoming dissolved. The onium salt compound (1) in its intramolecular salt form no longer functions as a quencher, therefore it does not capture the generated acid in the exposed section, thus achieving high sensitivity of the radiosensitive linear resin composition. On the other hand, in the unexposed section, the protected nitrogen atoms maintain a suitable alkalinity, enabling acid capture. As described above, it is speculated that the increased sensitivity resulting from the loss of quencher function in the exposed section complements the quencher function in the unexposed section, thereby improving the contrast between the exposed and unexposed sections and enabling the resist to perform its various properties. Furthermore, the increased solubility of the developer in the exposed section also suggests that residue formation can be suppressed, which further contributes to improved contrast.

[0012] In another embodiment of the present invention, there is a method for forming a pattern, comprising: The step of directly or indirectly coating the radiosensitive linear resin composition onto a substrate to form a resist film; The step of exposing the resist film; and The step of developing the exposed resist film using a developing solution.

[0013] In this pattern forming method, since the radiosensitive linear resin composition with excellent sensitivity, LWR performance, and CDU performance is used, high-quality resist patterns can be formed efficiently.

[0014] In another embodiment of the invention, the invention relates to an onium salt compound represented by the following formula (1) (i.e., onium salt compound (1)). [Chemistry 2] (in the above formula (1), R1 is a monovalent hydrocarbon group with 1 to 20 carbon atoms; R2 and R3 are each independently a monovalent hydrocarbon group with 1 to 20 carbon atoms, or represent a ring structure with 3 to 20 ring members formed by the combination of R2 and R3 together with the bonded carbon atoms; R4 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and L1 is a substituted or unsubstituted divalent linker having 1 to 40 carbon atoms, or represents a group containing a heterocyclic structure with 3 to 20 ring members, consisting of R4 and L1 bonded together with the nitrogen atoms bonded thereto; L2 is a single bond or a substituted or unsubstituted divalent linker with 1 to 40 carbon atoms; Rf1 and Rf2 are independently hydrogen atoms, fluorine atoms, monovalent hydrocarbon groups with 1 to 10 carbon atoms, or monovalent fluorinated hydrocarbon groups with 1 to 10 carbon atoms; when multiple Rf1 and Rf2 exist, the multiple Rf1 and Rf2 may be the same or different from each other; n is an integer from 1 to 4; Z+ is a monovalent radiosensitive linear onium cation.

[0015] The onium salt compound (1) in the resist film loses its quenching function in the exposed part and can exert a moderate alkalinity in the unexposed part. Therefore, when it is formulated into a radiosensitive linear resin composition, it can impart excellent sensitivity or LWR performance and CDU performance to the composition when forming resist patterns. Simple Explanation of the Diagram

[0016] none Implementation

[0017] The embodiments of the present invention will be described in detail below, but the present invention is not limited to these embodiments.

[0018] <Radiosensitive linear resin composition> The radiosensitive linear resin composition of this embodiment (hereinafter, also simply referred to as the "composition") comprises a specified onium salt compound (1), a resin, and a solvent. A radiosensitive linear acid generator may also be included as needed. The composition may also contain any other arbitrary components as long as it does not impair the effects of the present invention. By including the specified onium salt compound (1), the radiosensitive linear resin composition can be endowed with a high level of sensitivity, LWR performance, and CDU performance.

[0019] (Onium salt compound(1)) The onium salt compound (1) can function as a quencher (also known as a "photodegradable alkali" or "acid diffusion control agent") for capturing acids in the unexposed or pre-exposed portions. The onium salt compound (1) is represented by the formula (1).

[0020] In the formula (1), the monovalent hydrocarbon groups with 1 to 20 carbon atoms represented by R1, R2, R3 and R4 are not particularly limited, and can be listed as: monovalent chain hydrocarbon groups with 1 to 20 carbon atoms, monovalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms, monovalent aromatic hydrocarbon groups with 6 to 20 carbon atoms or combinations thereof.

[0021] Examples of monovalent chain hydrocarbon groups with 1 to 20 carbon atoms include straight-chain or branched saturated hydrocarbon groups with 1 to 20 carbon atoms, or straight-chain or branched unsaturated hydrocarbon groups with 1 to 20 carbon atoms.

[0022] Examples of monovalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms include monocyclic or polycyclic saturated hydrocarbon groups and monocyclic or polycyclic unsaturated hydrocarbon groups. Preferred monocyclic saturated hydrocarbon groups are cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Preferred polycyclic cycloalkyl groups are bridged alicyclic hydrocarbon groups such as norbornyl, adamantyl, tricyclic decyl, and tetracyclic dodecyl. Preferred monocyclic unsaturated hydrocarbon groups are monocyclic cycloalkenyl groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl. Preferred polycyclic unsaturated hydrocarbon groups are polycyclic cycloalkenyl groups such as norbornyl, tricyclic decenyl, and tetracyclic dodecenyl. Furthermore, a bridged alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group in which two non-adjacent carbon atoms constituting the alicyclic ring are bonded together by a chain bond containing one or more carbon atoms.

[0023] 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, and naphthylmethyl.

[0024] As a cyclic structure with 3 to 20 carbon atoms formed by the combination of R2 and R3 and together with the bonded carbon atoms, the structure obtained by removing one hydrogen atom from the monovalent alicyclic hydrocarbon group with 3 to 20 carbon atoms can be listed.

[0025] From the perspective of the structural stability of the tertiary alkoxy carbonyl group, R1, R2 and R3 are each preferably chain hydrocarbon groups with 1 to 5 carbon atoms.

[0026] In the formula (1), the substituted or unsubstituted divalent linker group represented by L1 and L2, having 1 to 40 carbon atoms, can be, for example, a divalent linear or branched hydrocarbon group having 1 to 40 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, a group selected from -CO-, -O-, -NH-, -S- and cyclic acetal structures, or a group formed by combining two or more of these groups.

[0027] Examples of divalent linear or branched hydrocarbon groups having 1 to 40 carbon atoms include: methanediyl, ethanediyl, propanediyl, butanediyl, hexanediyl, octanediyl, etc. Preferably, an alkyldiyl group having 1 to 8 carbon atoms is preferred.

[0028] Examples of divalent alicyclic hydrocarbon groups with 4 to 20 carbon atoms include monocyclic cycloalkane dimethyl groups such as cyclopentanediyl and cyclohexanediyl; and polycyclic cycloalkane dimethyl groups such as norbornenediyl and adamantanediyl. Preferably, a cycloalkane dimethyl group with 5 to 12 carbon atoms is preferred.

[0029] Substituents that replace some or all of the hydrogen atoms in L1 and L2 include, for example: halogen atoms such as fluorine, chlorine, bromine, and iodine, hydroxyl, carboxyl, cyano, nitro, alkoxy, alkoxycarbonyl, alkoxycarbonyloxy, acetyl, acetyloxy, etc.

[0030] As a heterocyclic structure containing 3 to 20 ring members (hereinafter also referred to as a "linking group containing a heterocyclic structure"), examples include groups containing aromatic heterocyclic structures and groups containing aliphatic heterocyclic structures. Aromatic structures with five-membered rings that acquire aromaticity by introducing heteroatoms are also included in heterocyclic structures. Examples of heteroatoms include oxygen atoms, nitrogen atoms, and sulfur atoms.

[0031] Examples of aromatic heterocyclic structures include: Aromatic heterocyclic structures containing oxygen atoms, such as furan, pyran, benzofuran, and benzopyran; Aromatic heterocyclic structures containing nitrogen atoms, such as pyrrole, imidazole, pyridine, pyrimidine, pyrazine, indole, quinoline, isoquinoline, acridine, phenazine, and carbazole; Thiophene and other aromatic heterocyclic structures containing sulfur atoms; Aromatic heterocyclic structures containing multiple heteroatoms, such as thiazoles, benzothiazoles, thiazides, and oxazines.

[0032] Examples of aliphatic heterocyclic structures include: Alicyclic and heterocyclic structures containing oxygen atoms, such as oxacyclopropane, tetrahydrofuran, tetrahydropyran, dioxane, and dioxane; Alicyclic and heterocyclic structures containing nitrogen atoms, such as aziridine, pyrrolidine, piperidine, and piperazine; Thietane, thiocyclopentane, thiane, and other alicyclic and heterocyclic structures containing sulfur atoms; Morpholine, 1,2-oxathionecyclopentane, 1,3-oxathionecyclopentane, and other alicyclic and heterocyclic structures containing multiple heteroatoms; Lactone structure, cyclic carbonate structure, cyclic acetal structure, and sulfonolactone structure; Spirocyclic heterocyclic structures, etc., in which multiple aliphatic heterocyclic structures share a quaternary carbon atom for bonding.

[0033] As the linker for the heterocyclic structure, not only can a heterocyclic structure containing a nitrogen atom be used, but also preferably a combination of a heterocyclic structure containing a nitrogen atom, a heterocyclic structure containing heteroatoms other than nitrogen atoms, and at least one of the divalent linkers represented by L1. As the heterocyclic structure containing a nitrogen atom, a pyrrolidine structure or a piperidine structure is preferred.

[0034] From the viewpoint of ease of intramolecular salt formation, L2 is preferably a substituted or unsubstituted divalent chain hydrocarbon group with 1 to 10 carbon atoms.

[0035] In the above formula (1), regarding the monovalent hydrocarbon groups with 1 to 10 carbons represented by R f1 and R f2, it is preferable to adopt the structure corresponding to the monovalent hydrocarbon groups with 1 to 10 carbons represented by R 1 with 1 to 20 carbons.

[0036] In the formula (1), the monovalent fluorinated hydrocarbon groups with 1 to 10 carbon atoms represented by R f1 and R f2 can be, for example, monovalent fluorinated chain hydrocarbon groups with 1 to 10 carbon atoms, monovalent fluorinated alicyclic hydrocarbon groups with 3 to 10 carbon atoms, etc.

[0037] Examples of monovalent fluorinated chain hydrocarbon groups having 1 to 10 carbon atoms include: Trifluoromethyl, 2,2,2-trifluoroethyl, pentafluoroethyl, 2,2,3,3,3-pentafluoropropyl, 1,1,1,3,3,3-hexafluoropropyl, heptafluoron-propyl, heptafluoroisopropyl, nonafluoron-butyl, nonafluoroisobutyl, nonafluorotert-butyl, 2,2,3,3,4,4,5,5-octafluoron-pentyl, tridecafluoron-hexyl, 5,5,5-trifluoro-1,1-diethylpentyl and other fluorinated alkyl groups; fluorinated alkenyl groups such as trifluorovinyl and pentafluoropropylene; Fluoroacetylene, trifluoropropynyl, and other fluorinated acetylene groups, etc.

[0038] Examples of monovalent fluorinated alicyclic hydrocarbon groups having 3 to 10 carbon atoms include: Fluorocyclopentyl, difluorocyclopentyl, nonafluorocyclopentyl, fluorocyclohexyl, difluorocyclohexyl, undecylfluorocyclohexylmethyl, fluoronorborneol, fluoroadamantyl, fluoroborneol, fluoroisoborneol, fluorotricyclodecyl, and other fluorinated cycloalkyl groups; Fluorinated cyclopentenyl, nonafluorocyclohexenyl, and other fluorinated cycloalkenyl groups.

[0039] The fluorinated hydrocarbon group is preferably a monovalent fluorinated chain hydrocarbon group having 1 to 10 carbon atoms, more preferably a monovalent fluorinated alkyl group having 1 to 10 carbon atoms, and even more preferably a perfluoroalkyl group having 1 to 6 carbon atoms, and particularly preferably a straight-chain perfluoroalkyl group having 1 to 6 carbon atoms.

[0040] n is preferably an integer between 1 and 3, and even better if it is 1 or 2.

[0041] As the anionic part of the onium salt compound (1) represented by the formula (1), although there is no particular limitation, for example, the structures represented by the formulas (1a) to (1z) below can be listed.

[0042] [Chemistry 3]

[0043] [Chemistry 4]

[0044] [Chemistry 5]

[0045] In the above formula, Z + has the same meaning as in formula (1).

[0046] In formula (1), the monovalent radiosensitive linear onyx cation represented by Z+ can be, for example, radiodegradable onyx cations containing elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi, such as strontium cation, tetrahydrothiophene onyx cation, monium cation, phosphonium cation, diazoonium cation, and pyridinium cation. Preferably, it is a strontium cation or a monium cation. The strontium cation or the monium cation is preferably represented by formulas (X-1) to (X-6) below.

[0047] [Chemistry 6]

[0048] In formula (X-1), Ra1, Ra2, and Ra3 are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, alkoxy groups or alkoxycarbonyl groups, substituted or unsubstituted monocyclic or polycyclic cycloalkyl groups having 3 to 12 carbon atoms, substituted or unsubstituted aromatic hydrocarbon groups having 6 to 12 carbon atoms, hydroxyl groups, halogen atoms, -OSO 2-RP, -SO 2-RQ, or -SR T, or represent a ring structure formed by the combination of two or more of these groups. The ring structure may contain heteroatoms such as O or S between the carbon-carbon bonds forming the backbone. RP, RQ, and RT are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, substituted or unsubstituted alicyclic hydrocarbon groups having 5 to 25 carbon atoms, or substituted or unsubstituted aromatic hydrocarbon groups having 6 to 12 carbon atoms. k1, k2, and k3 are independently integers from 0 to 5. When there are multiple Ra1~Ra3, as well as multiple RP, RQ and RT, the multiple Ra1~Ra3, as well as multiple RP, RQ and RT can be the same or different.

[0049] In formula (X-2), Rb1 is a substituted or unsubstituted linear or branched alkyl or alkoxy group with 1 to 20 carbon atoms, a substituted or unsubstituted acetyl group with 2 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group with 6 to 8 carbon atoms, or a hydroxyl group. nk is 0 or 1. When nk is 0, k4 is an integer from 0 to 4; when nk is 1, k4 is an integer from 0 to 7. When there are multiple Rb1 groups, they may be the same or different. Furthermore, multiple Rb1 groups may also exhibit a ring structure formed by mutual bonding. Rb2 is a substituted or unsubstituted linear or branched alkyl group with 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group with 6 or 7 carbon atoms. LC is a single bond or a divalent linkage. k5 is an integer from 0 to 4. When there are multiple Rb2s, these Rb2s can be the same or different. Furthermore, multiple Rb2s can also form a ring structure by combining with each other. q is an integer from 0 to 3. In the formula, ring structures containing S+ can contain heteroatoms such as O or S between the carbon-carbon bonds forming the framework.

[0050] In formula (X-3), Rc1, Rc2 and Rc3 are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms.

[0051] In formula (X-4), R g1 is a substituted or unsubstituted linear or branched alkyl or alkoxy group with 1 to 20 carbon atoms, a substituted or unsubstituted acetyl group with 2 to 8 carbon atoms, an substituted or unsubstituted aromatic hydrocarbon group with 6 to 8 carbon atoms, or a hydroxyl group. n k2 is 0 or 1. When n k2 is 0, k10 is an integer from 0 to 4, and when n k2 is 1, k10 is an integer from 0 to 7. When there are multiple R g1s, the multiple R g1s can be the same or different. In addition, the multiple R g1s can also be a ring structure formed by mutual bonding. R g2 and R g3 are independently substituted or unsubstituted linear or branched alkyl groups, alkoxy groups or alkoxycarbonyl groups with 1 to 12 carbon atoms, substituted or unsubstituted monocyclic or polycyclic cycloalkyl groups with 3 to 12 carbon atoms, substituted or unsubstituted aromatic hydrocarbon groups with 6 to 12 carbon atoms, hydroxyl groups, halogen atoms, or represent a ring structure formed by the combination of these groups. k11 and k12 are independently integers from 0 to 4. When there are multiple R g2 and R g3, the multiple R g2 and R g3 can be the same or different.

[0052] In formula (X-5), Rd1 and Rd2 are independently substituted or unsubstituted linear or branched alkyl groups, alkoxy or alkoxycarbonyl groups, substituted or unsubstituted aromatic hydrocarbon groups with 6 to 12 carbon atoms, halogen atoms, halogenated alkyl groups with 1 to 4 carbon atoms, nitro groups, or represent a ring structure formed by the combination of two or more of these groups. k6 and k7 are independently integers from 0 to 5. When there are multiple Rd1 and Rd2, the multiple Rd1 and Rd2 can be the same or different.

[0053] In formula (X-6), Re1 and Re2 are independently halogen atoms, substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, or substituted or unsubstituted aromatic hydrocarbon groups having 6 to 12 carbon atoms. k8 and k9 are independently integers from 0 to 4.

[0054] The onium salt compound (1) can be formed by any combination of the anionic moiety specified in formula (1) and the monovalent radiosensitive linear onium cation. As a specific example of the onium salt compound (1), although there is no particular limitation, the structures represented by formulas (1-1) to (1-26) can be listed for example.

[0055] [Chemistry 7]

[0056] [Chemistry 8]

[0057] [Chemistry 9]

[0058] Preferably, it is an onium salt compound (1) represented by formulas (1-1) to (1-24).

[0059] Compared to 100 parts by weight of the resin described later, the content of onium salt compound (1) in the radiosensitive linear resin composition of this embodiment (the total of such compounds when multiple onium salt compounds are used together) is preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, and particularly preferably 0.5 parts by weight or more. The content is more preferably 25 parts by weight or less, more preferably 20 parts by weight or less, and particularly preferably 15 parts by weight or less. Furthermore, the content of onium salt compound (1) can be appropriately selected according to the type of resin used, the exposure conditions, the required sensitivity, and the type or content of the radiosensitive linear acid generator described later. This allows for excellent sensitivity, LWR performance, and CDU performance when forming resist patterns.

[0060] (Synthetic method of onium salt compound (1)) As an example of the onium salt compound (1), the case where R4 and L1 form a piperidine ring structure will be described. Typically, as shown in the following process, the haloalcohol is reacted with a protected piperidine carboxylate to form an ester, the dithionite is reacted with an oxidant to form a sulfonate, and finally, salt exchange is performed by reacting with the onium cation halide corresponding to the onium cation moiety, thereby synthesizing the target onium salt compound (1).

[0061] [Chemistry 10] (In the formula, R1, R2, R3, L2, Rf1, Rf2, Z+, and n have the same meaning as in the above formula (1); Xh1 and Xh2 are halogen atoms)

[0062] Onium salt compounds (1) with other structures can also be synthesized by means of a halogenated alcohol or a carboxylic acid body with a nitrogen atom protected as the basis for the anionic moiety, and a precursor corresponding to the onium cation moiety.

[0063] (Other acid diffusion control agents) Provided that the effects of the present invention are not compromised, the radiosensitive linear resin composition may also contain other acid diffusion control agents. Examples of other acid diffusion control agents include, for instance, ononium salt compounds other than ononium salt compounds (1) that produce relatively weak acids compared to the radiosensitive linear acid generators described later. Specific examples include compounds represented by the following formulas.

[0064] [Chemistry 11]

[0065] Other acid diffusion control agents include nitrogen-containing compounds other than onium salt compounds (1), such as amine compounds, diamine compounds, polyamine compounds, compounds containing amide groups, urea compounds, nitrogen-containing heterocyclic compounds, etc. These nitrogen-containing compounds can also be compounds with a tertiary alkoxycarbonyl group protecting the nitrogen atom. These acid diffusion control agents can be used alone or in combination of two or more.

[0066] (resin) The resin is an aggregate of polymers containing structural units (hereinafter also referred to as "structural units (I)") containing acid-dissociable groups (hereinafter also referred to as "base resin"). An "acid-dissociable group" refers to a group that substitutes for hydrogen atoms in carboxyl groups, phenolic hydroxyl groups, alcoholic hydroxyl groups, sulfonyl groups, etc., and is a group that dissociates under the action of an acid. This radiosensitive linear resin composition exhibits excellent pattern-forming properties due to the presence of structural units (I) in the resin.

[0067] The base resin preferably has, in addition to structural unit (I), structural unit (II) which includes at least one of the group consisting of lactone structures, cyclic carbonate structures, and sulfonyl lactone structures, as described later. It may also have other structural units besides structural unit (I) and structural unit (II). Each structural unit will be described below.

[0068] [Structural Unit (I)] Structural unit (I) is a structural unit containing an acid-dissociating group. As long as structural unit (I) contains an acid-dissociating group, there is no particular limitation. For example, structural units with a tertiary alkyl ester moiety, structural units with a phenolic hydroxyl group whose hydrogen atom is substituted by a tertiary alkyl group, and structural units with an acetal bond can be listed. From the viewpoint of improving the pattern-forming properties of the radiosensitive linear resin composition, the structural unit represented by the following formula (3) is preferred (hereinafter also referred to as "structural unit (I-1)").

[0069] [Chemistry 12]

[0070] In formula (3), R7 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R8 is a monovalent hydrocarbon group with 1 to 20 carbon atoms. R9 and R10 are independently monovalent chain hydrocarbon groups with 1 to 10 carbon atoms or monovalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms, or represent divalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms formed by the combination of these groups with the carbon atoms they are bonded to.

[0071] As for R 7, from the viewpoint of providing the copolymerization of the monolith of the structural unit (I-1), it is preferably a hydrogen atom, a methyl group, and more preferably a methyl group.

[0072] Examples of monovalent hydrocarbon groups with 1 to 20 carbon atoms represented by R 8 include: chain hydrocarbon groups with 1 to 10 carbon atoms, monovalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms, and monovalent aromatic hydrocarbon groups with 6 to 20 carbon atoms.

[0073] As the chain hydrocarbon groups with 1 to 10 carbon atoms represented by R 8 to R 10, examples include straight-chain or branched saturated hydrocarbon groups with 1 to 10 carbon atoms, or straight-chain or branched unsaturated hydrocarbon groups with 1 to 10 carbon atoms.

[0074] As the alicyclic hydrocarbon group with 3 to 20 carbon atoms represented by R 8 to R 10, examples include monocyclic or polycyclic saturated hydrocarbon groups, or monocyclic or polycyclic unsaturated hydrocarbon groups. Preferred monocyclic saturated hydrocarbon groups are cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Preferred polycyclic cycloalkyl groups are bridged alicyclic hydrocarbon groups such as norbornyl, adamantyl, tricyclic decyl, and tetracyclic dodecyl. Furthermore, a bridged alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group in which two non-adjacent carbon atoms constituting the alicyclic ring are bonded together by a chain bond containing one or more carbon atoms.

[0075] Examples of monovalent aromatic hydrocarbon groups with 6 to 20 carbon atoms represented by R 8 include: Aryl groups such as phenyl, tolyl, xylyl, naphthyl, and anthracene; aralkyl groups such as benzyl, phenethyl, and naphthylmethyl.

[0076] R8 is preferably a straight-chain or branched saturated hydrocarbon group with 1 to 10 carbon atoms, or an alicyclic hydrocarbon group with 3 to 20 carbon atoms.

[0077] The chain-like hydrocarbon groups or alicyclic hydrocarbon groups represented by R9 and R10, which are combined with each other and together with the bonded carbon atoms to form a divalent alicyclic group with 3 to 20 carbon atoms, are not particularly limited as long as they are formed by removing two hydrogen atoms from the same carbon atom of the carbon ring of the monocyclic or polycyclic alicyclic hydrocarbon constituting the aforementioned number of carbons. They can be any type of monocyclic or polycyclic hydrocarbon group. As a polycyclic hydrocarbon group, it can be any type of bridged alicyclic hydrocarbon group or condensed alicyclic hydrocarbon group, and it can also be any type of saturated or unsaturated hydrocarbon group. Furthermore, a condensed alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group formed by multiple alicyclic rings sharing a common edge (the bond between two adjacent carbon atoms).

[0078] As a monocyclic alicyclic hydrocarbon group, saturated hydrocarbon groups are preferably cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, cyclooctanediyl, etc., and as unsaturated hydrocarbon groups, preferably cyclopentenidyl, cyclohexenidyl, cycloheptenidyl, cyclooctenidyl, cyclodecenidyl, etc. As a polycyclic alicyclic hydrocarbon group, bridged alicyclic saturated hydrocarbon groups are preferred, such as bicyclic [2.2.1]heptane-2,2-diyl (norbornene-2,2-diyl), bicyclic [2.2.2]octane-2,2-diyl, tricyclic [3.3.1.1 3,7]decane-2,2-diyl (adamantane-2,2-diyl), etc.

[0079] In these, it is preferred that R8 is an alkyl group having 1 to 4 carbon atoms, and that R9 and R10 are bonded together with the carbon atoms bonded thereto to form an alicyclic structure that is a polycyclic or monocyclic cycloalkane structure.

[0080] As a structural unit (I-1), for example, the structural units represented by the following equations (3-1) to (3-6) (hereinafter also referred to as "structural unit (I-1-1) to structural unit (I-1-6)") can be listed.

[0081] [Chemistry 13]

[0082] In equations (3-1) to (3-6), R7 to R10 have the same meaning as in equation (3). i and j are independent integers from 1 to 4. k and l are 0 or 1.

[0083] As i and j, 1 is preferred. As R 8, methyl, ethyl or isopropyl is preferred. As R 9 and R 10, methyl or ethyl is preferred.

[0084] The base resin may also contain one or more structural units (I).

[0085] Relative to all structural units constituting the base resin, the content ratio of structural unit (I) (the total content ratio when multiple units are included) is preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 30 mol% or more, and particularly preferably 35 mol% or more. Additionally, it is preferably 80 mol% or less, more preferably 75 mol% or less, further preferably 70 mol% or less, and particularly preferably 65 mol% or less. By setting the content ratio of structural unit (I) within the aforementioned range, the pattern-forming property of the radiosensitive linear resin composition can be further improved.

[0086] [Structural Unit (II)] Structural unit (II) is a structural unit comprising at least one selected from the group consisting of lactone structures, cyclic carbonate structures, and sulfonyl lactone structures. By further having structural unit (II), the solubility of the base resin in the developer can be adjusted, resulting in improved lithography properties such as resolution of the radiosensitive linear resin composition. Furthermore, the adhesion between the resist pattern formed by the base resin and the substrate can be improved.

[0087] As a structural unit (II), for example, the structural units represented by the following equations (T-1) to (T-10) can be listed.

[0088] [Chemistry 14]

[0089] In the formula, RL1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. RL2 to RL5 are independently hydrogen atoms, alkyl groups with 1 to 4 carbon atoms, cyano groups, trifluoromethyl groups, methoxy groups, methoxycarbonyl groups, hydroxyl groups, hydroxymethyl groups, or dimethylamino groups. RL4 and RL5 can also be divalent alicyclic groups with 3 to 8 carbon atoms that are bonded together with each other. L2 is a single bond or a divalent linker. X is an oxygen atom or a methylene group. k is an integer from 0 to 3. m is an integer from 1 to 3.

[0090] As a divalent alicyclic group with 3 to 8 carbon atoms formed by the combination of R L4 and R L5 with the bonded carbon atoms, examples include chain hydrocarbon groups or alicyclic hydrocarbon groups represented by R 9 and R 10 in formula (3) that are combined with the bonded carbon atoms to form a divalent alicyclic group with 3 to 20 carbon atoms, in which the carbon number is 3 to 8. One or more hydrogen atoms on the alicyclic group may also be substituted with hydroxyl groups.

[0091] Examples of divalent linking groups represented by L2 include: divalent linear or branched hydrocarbon groups with 1 to 10 carbon atoms, divalent alicyclic hydrocarbon groups with 4 to 12 carbon atoms, or groups consisting of one or more of these hydrocarbon groups and at least one of the groups selected from -CO-, -O-, -NH- and -S-.

[0092] As structural unit (II), these are preferably structural units containing a lactone structure, more preferably structural units containing a norbornene lactone structure, and even more preferably structural units derived from norbornene lactone-based esters of (meth)acrylate.

[0093] Of all the structural units constituting the base resin, the content of structural unit (II) is preferably 20 mol% or more, more preferably 25 mol% or more, and even more preferably 30 mol% or more. Furthermore, it is preferably 80 mol% or less, more preferably 75 mol% or less, and even more preferably 70 mol% or less. By setting the content of structural unit (II) within the aforementioned range, the lithography properties such as resolution of the radiosensitive linear resin composition and the adhesion between the formed resist pattern and the substrate can be further improved.

[0094] [Structural Unit (III)] In addition to the structural units (I) and (II) described above, the base resin may also optionally have other structural units. Examples of these other structural units include structural units (III) containing polar groups (excluding those equivalent to structural unit (II)). By further including structural unit (III), the base resin can adjust its solubility in the developer, thereby improving the photolithography properties of the radiosensitive linear resin composition, such as resolution. Examples of these polar groups include hydroxyl, carboxyl, cyano, nitro, and sulfonamide groups. Among these, hydroxyl and carboxyl groups are preferred, and hydroxyl groups are even more preferred.

[0095] As a structural unit (III), for example, structural units represented by the following formulas can be listed.

[0096] [Chemistry 15]

[0097] In the formula, RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0098] When the base resin contains the structural unit (III) with polar groups, the content of the structural unit (III) is preferably 5 mol% or more, more preferably 8 mol% or more, and even more preferably 10 mol% or more, relative to all the structural units constituting the base resin. Furthermore, it is preferably 40 mol% or less, more preferably 35 mol% or less, and even more preferably 30 mol% or less. By setting the content of the structural unit (III) within the aforementioned range, the lithography properties, such as resolution, of the radiosensitive linear resin composition can be further improved.

[0099] [Structural Unit (IV)] As other structural units, in addition to the structural unit (III) with polar groups, the base resin may optionally have structural units derived from hydroxyl styrene or structural units with phenolic hydroxyl groups (hereinafter, both are also referred to as "structural unit (IV)"). Structural unit (IV) contributes to improved etch resistance and increased difference in developer solubility (solution contrast) between exposed and unexposed areas. It is particularly suitable for pattern formation using exposure to radiation with wavelengths below 50 nm, such as electron beams or EUV. In this case, the resin preferably has both structural unit (IV) and structural unit (I) or structural unit (III).

[0100] In this case, it is preferable to polymerize in a state where the phenolic hydroxyl groups are protected by protecting groups such as base-dissociating groups, and then hydrolyze and deprotect the polymer to obtain the structural unit (IV). As the structural unit that provides the structural unit (IV) by hydrolysis, it is preferable to be represented by the following formulas (4-1) and (4-2).

[0101] [Chemistry 16]

[0102] In formulas (4-1) and (4-2), R11 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R12 is a monovalent hydrocarbon group or alkoxy group with 1 to 20 carbon atoms. Examples of monovalent hydrocarbon groups with 1 to 20 carbon atoms in R12 include the monovalent hydrocarbon group with 1 to 20 carbon atoms in R8 of structural unit (I). Examples of alkoxy groups include methoxy, ethoxy, and tributoxy.

[0103] R12 is preferably alkyl or alkoxy, and more preferably methyl or tributoxy.

[0104] In the case of resins exposed to radiation with wavelengths of 50 nm or less, the content of structural unit (IV) is preferably 10 mol% or more, more preferably 20 mol% or more, relative to all structural units constituting the resin. Furthermore, it is preferably 70 mol% or less, more preferably 60 mol% or less.

[0105] (Synthesis methods of basic resins) The basic resin can be synthesized, for example, by using free radical polymerization initiators, to polymerize monomers that provide each structural unit in a suitable solvent.

[0106] Examples of free radical polymerization initiators include: azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), dimethyl 2,2'-azobisisobutyrate, and other azo-based free radical initiators; and peroxide-based free radical initiators such as benzoyl peroxide, tert-butyl hydroperoxide, and cumene hydroperoxide. Among these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred, and AIBN is even more preferred. These free radical initiators can be used alone or in combination of two or more.

[0107] Examples of solvents used in the polymerization include: Alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decahydronaphthalene, and norbornene; Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and cumene; Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, and chlorobenzene; Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, and methyl propionate; Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, and 2-heptanone; Ethers such as tetrahydrofuran, dimethoxyethane, and diethoxyethane; Methanol, ethanol, 1-propanol, 2-propanol, 4-methyl-2-pentanol, and other alcohols. These solvents used in the polymerization can be used alone or in combination of two or more.

[0108] The reaction temperature in the polymerization is typically 40°C to 150°C, preferably 50°C to 120°C. The reaction time is typically 1 hour to 48 hours, preferably 1 hour to 24 hours.

[0109] The molecular weight of the base resin is not particularly limited, but the equivalent weight average molecular weight (Mw) of polystyrene obtained by gel permeation chromatography (GPC) is preferably 1,000 or more, more preferably 2,000 or more, even more preferably 3,000 or more, and particularly preferably 4,000 or more. Furthermore, Mw is preferably 50,000 or less, more preferably 30,000 or less, even more preferably 15,000 or less, and particularly preferably 12,000 or less. If the Mw of the base resin does not meet the lower limit, the heat resistance of the obtained resist film may decrease. If the Mw of the base resin exceeds the upper limit, the developability of the resist film may decrease.

[0110] The ratio (Mw / Mn) of the base resin to the equivalent number average molecular weight (Mn) of the polystyrene obtained by GPC is typically 1 or more and 5 or less, preferably 1 or more and 3 or less, and even more preferably 1 or more and 2 or less.

[0111] The Mw and Mn values ​​of the resin in this specification are values ​​determined by gel permeation chromatography (GPC) under the following conditions.

[0112] GPC tubing: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (all manufactured by Tosoh) Column temperature: 40℃ Dissolution solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0113] The proportion of the base resin relative to the total solid content of the radiosensitive linear resin composition is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more.

[0114] (Other resins) The radiosensitive linear resin composition of this embodiment may also include a resin with a higher mass content of fluorine atoms than the base resin (hereinafter also referred to as "high fluorine content resin") as other resins. When the radiosensitive linear resin composition contains a high fluorine content resin, it may be more concentrated on the surface of the resist film relative to the base resin, thereby improving the water repellency of the resist film surface during immersion exposure.

[0115] As a high-fluorine content resin, it is preferred to have, for example, the structural unit represented by the following formula (5) (hereinafter also referred to as "structural unit (V)"). It may also have structural unit (I) or structural unit (II) in the base resin as needed.

[0116] [Chemistry 17]

[0117] In formula (5), R13 is a hydrogen atom, methyl or trifluoromethyl. GL is a single bond, oxygen atom, sulfur atom, -COO-, -SO2ONH-, -CONH- or -OCONH-. R14 is a monovalent fluorinated chain hydrocarbon group with 1 to 20 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group with 3 to 20 carbon atoms.

[0118] As for R13, from the viewpoint of providing the copolymerization of the monolithic structural unit (V), it is preferred to have hydrogen atoms and methyl groups, and more preferably methyl groups.

[0119] As for the GL, from the viewpoint of providing the copolymerization of the monolithic structural unit (V), it is preferred to have a single bond and -COO-, more preferably -COO-.

[0120] As the monovalent fluorinated chain hydrocarbon group with 1 to 20 carbon atoms represented by R 1 4, examples include those formed by substituting some or all of the hydrogen atoms of a straight-chain or branched alkyl group with 1 to 20 carbon atoms with fluorine atoms.

[0121] As the monovalent fluorinated alicyclic hydrocarbon group with 3 to 20 carbon atoms represented by R 1 4, examples include those formed by replacing some or all of the hydrogen atoms of a monocyclic or polycyclic hydrocarbon group with 3 to 20 carbon atoms with fluorine atoms.

[0122] As R14, it is preferably a fluorinated chain hydrocarbon group, more preferably a fluorinated alkyl group, and even more preferably 2,2,2-trifluoroethyl, 1,1,1,3,3,3-hexafluoro-2-propyl and 5,5,5-trifluoro-1,1-diethylpentyl.

[0123] When a high-fluorine content resin has structural units (V), the content of structural units (V) relative to all structural units constituting the high-fluorine content resin is preferably 30 mol% or more, more preferably 40 mol% or more, further preferably 45 mol% or more, and particularly preferably 50 mol% or more. Additionally, it is preferably 90 mol% or less, more preferably 85 mol% or less, and further preferably 80 mol% or less. By setting the content of structural units (V) within the aforementioned range, the mass content of fluorine atoms in the high-fluorine content resin can be more appropriately adjusted, further promoting the biased presence on the surface of the resist film. As a result, the water repellency of the resist film during immersion exposure can be further improved.

[0124] High-fluorine-content resins can also have fluorine-containing structural units (hereinafter also referred to as structural units (VI)) as represented by the following formula (f-2), either together with or in place of structural unit (V). By having structural units (f-2) in high-fluorine-content resins, the solubility in alkaline developers can be improved, and the generation of development defects can be suppressed.

[0125] [Chemistry 18]

[0126] Structural unit (VI) is broadly classified into two cases: one with a base-soluble group (x) and the other with a group (y) that dissociates under the action of a base and has increased solubility in alkaline developing solutions (hereinafter also referred to as "base-dissociatable group"). Both (x) and (y) are common. In formula (f-2), RC is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. RD is a single bond, a (s+1) valent hydrocarbon group with 1 to 20 carbon atoms, a structure formed by bonding an oxygen atom, a sulfur atom, -NR dd-, a carbonyl group, -COO-, or -CONH- to the RE side of the hydrocarbon group, or a structure formed by substituting a portion of the hydrogen atom of the hydrocarbon group with an organic group having a heteroatom. R dd is a hydrogen atom or a monovalent hydrocarbon group with 1 to 10 carbon atoms. s is an integer from 1 to 3.

[0127] When structural unit (VI) has a base-soluble group (x), RF is a hydrogen atom, and A1 is an oxygen atom, -COO-*, or -SO2O-*. * indicates the site bonded to RF. W1 is a single bond, a hydrocarbon group with 1 to 20 carbon atoms, or a divalent fluorinated hydrocarbon group. When A1 is an oxygen atom, W1 is a fluorinated hydrocarbon group with a fluorine atom or fluoroalkyl group on the carbon atom bonded to A1. RE is a single bond or a divalent organic group with 1 to 20 carbon atoms. When s is 2 or 3, multiple REs, W1s, A1s, and RFs can be the same or different. By having a base-soluble group (x) in structural unit (VI), the affinity for alkaline developers can be improved, and development defects can be suppressed. As a structural unit (VI) having a base-soluble group (x), it is particularly preferred that A 1 is an oxygen atom and W 1 is 1,1,1,3,3,3-hexafluoro-2,2-methanediyl.

[0128] When structural unit (VI) has a base-dissociable group (y), RF is a monovalent organic group with 1 to 30 carbon atoms, and A1 is an oxygen atom, -NR aa-, -COO-*, or -SO 2O-*. Raa is a hydrogen atom or a monovalent hydrocarbon group with 1 to 10 carbon atoms. * indicates the site bonded to RF. W1 is a single bond or a divalent fluorinated hydrocarbon group with 1 to 20 carbon atoms. RE is a single bond or a divalent organic group with 1 to 20 carbon atoms. When A1 is -COO-* or -SO 2O-*, W1 or RF has a fluorine atom on the carbon atom bonded to A1 or on the adjacent carbon atom. When A1 is an oxygen atom, W1 and RE are single bonds, RD is a structure formed by a carbonyl group bonded to the end of the RE side of a hydrocarbon group with 1 to 20 carbon atoms, and RF is an organic group with a fluorine atom. When s is 2 or 3, multiple REs, W1, A1, and RFs can be the same or different. By having a (y) alkali-dissociative group in the structural unit (VI), the resist film surface changes from hydrophobic to hydrophilic during the alkaline development step. As a result, the affinity for the developer can be significantly improved, and development defects can be suppressed more efficiently. Preferably, the structural unit (VI) with the (y) alkali-dissociative group is A1 which is -COO-* and RF or W1, or both of these, have fluorine atoms.

[0129] From the viewpoint of providing the copolymerization of the monolithic structural unit (VI), hydrogen atoms and methyl groups are preferred as RC, and methyl groups are even more preferred.

[0130] When RE is a divalent organic group, it is preferably a group with a lactone structure, more preferably a group with a polycyclic lactone structure, and even more preferably a group with a norbornene lactone structure.

[0131] When a high-fluorine content resin has structural unit (VI), the content of structural unit (VI) relative to all structural units constituting the high-fluorine content resin is preferably 50 mol% or more, more preferably 55 mol% or more, and even more preferably 60 mol% or more. Furthermore, it is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less. By setting the content of structural unit (VI) within the aforementioned range, the water repellency of the resist film during immersion exposure can be further improved.

[0132] [Other structural units] High-fluorine resins may also contain structural units having an alicyclic structure as represented by the following formula (6) as structural units other than those listed above. [Chemistry 19] (In formula (6), R1α is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; R2α is a monovalent alicyclic hydrocarbon group with 3 to 20 carbon atoms)

[0133] In the formula (6), the monovalent alicyclic hydrocarbon group with 3 to 20 carbon atoms represented by R 2α can preferably be the monovalent alicyclic hydrocarbon group with 3 to 20 carbon atoms represented by R 8 in the formula (1).

[0134] When a high-fluorine content resin contains the aforementioned alicyclic structural unit, the proportion of the alicyclic structural unit is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 30 mol% or more, relative to all structural units constituting the high-fluorine content resin. Furthermore, it is preferably 60 mol% or less, more preferably 50 mol% or less, and even more preferably 450 mol% or less.

[0135] The Mw of the high fluorine content resin is preferably 1,000 or more, more preferably 2,000 or more, even more preferably 3,000 or more, and particularly preferably 5,000 or more. The Mw is preferably 50,000 or less, more preferably 30,000 or less, even more preferably 15,000 or less, and particularly preferably 12,000 or less.

[0136] The lower limit of Mw / Mn for high-fluorine content resins is typically 1, more preferably 1.1. The upper limit of Mw / Mn is typically 5, more preferably 3, more preferably 2, and even more preferably 1.9.

[0137] Relative to 100 parts by weight of the base resin, the content of the high-fluorine resin is preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, even more preferably 1 part by weight or more, and particularly preferably 1.5 parts by weight or more. Furthermore, it is preferably 15 parts by weight or less, more preferably 12 parts by weight or less, even more preferably 10 parts by weight or less, and particularly preferably 8 parts by weight or less.

[0138] By setting the content of the high-fluorine resin within the aforementioned range, the high-fluorine resin can be more effectively concentrated on the surface of the resist film, thereby further improving the water repellency of the resist film surface during immersion exposure. This radiosensitive linear resin composition may contain one or more high-fluorine resins.

[0139] (Synthesis method of high fluorine content resin) High-fluorine content resins can be synthesized using the same method as the base resin.

[0140] (Radiosensitive linear acid generator) The radiosensitive linear resin composition of this embodiment preferably further includes a radiosensitive linear acid generator, which generates an acid with a smaller pKa than the acid generated by the onium salt compound (1) which acts as an acid diffusion control agent, i.e., a relatively strong acid, when exposed to radiation (exposure). When the resin contains structural units (I) with acid-dissociative groups, the acid generated by the radiosensitive linear acid generator upon exposure can dissociate the acid-dissociative groups of the structural unit (I), thereby generating carboxyl groups, etc. This function differs from that of the onium salt compound (1), which, under the patterning conditions using the radiosensitive linear resin composition, substantially does not dissociate the acid-dissociative groups of the structural units (I) of the resin, thus suppressing the diffusion of the acid generated by the radiosensitive linear acid generator in the unexposed areas. The different functions of the onium salt compound (1) and the radiosensitive linear acid generator are determined by the energy required for the dissociation of the acid-dissociating groups in the structural unit (I) of the resin, and the thermal conditions imparted when forming a pattern using the radiosensitive linear resin composition. The radiosensitive linear acid generator contained in the radiosensitive linear resin composition may exist as a compound alone (free from the polymer), or may be incorporated as part of the polymer, or may be both, but it is preferred to exist as a compound alone.

[0141] By including the radiosensitive linear resin composition containing the radiosensitive linear acid generator, the polarity of the resin in the exposure section increases. The resin in the exposure section becomes soluble in the developer when developed in an alkaline aqueous solution, but becomes insoluble in the developer when developed in an organic solvent.

[0142] Examples of radiosensitive linear acid generators include: onium salt compounds (excluding said onium salt compound (1)), sulfadiazine compounds, halogen-containing compounds, diazonium ketone compounds, etc. Examples of onium salt compounds include: strontium salts, tetrahydrothiophene onium salts, ferrophosphate salts, phosphonium salts, diazonium salts, pyridinium salts, etc. Among these, strontium salts and ferrophosphate salts are preferred.

[0143] Examples of acids produced by exposure include sulfonic acids. Examples of such acids include strontium salts with anions in which one or more fluorine atoms or fluorinated hydrocarbon groups are substituted on the carbon atom adjacent to the sulfonate group. Among these, those having cyclic structures in both the cation and anion are particularly preferred as radiosensitive linear acid generators.

[0144] These radiosensitive linear acid generators can be used alone or in combination of two or more. The content of the radiosensitive linear acid generator (the total of all radiosensitive linear acid generators used in combination) relative to 100 parts by weight of the base resin is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, and even more preferably 5 parts by weight or more. Furthermore, relative to 100 parts by weight of the resin, it is preferably 40 parts by weight or less, more preferably 35 parts by weight or less, even more preferably 30 parts by weight or less, and particularly preferably 20 parts by weight or less. This allows for excellent sensitivity or LWR and CDU performance when forming resist patterns.

[0145] (solvent) The radiosensitive linear resin composition of this embodiment contains a solvent. There are no particular limitations on whether the solvent is a solvent that can at least dissolve or disperse compound (1) and resin, and, if necessary, a radiosensitive linear acid generator.

[0146] Examples of solvents include: alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, and hydrocarbon solvents.

[0147] Examples of alcohol-based solvents include: Monohydric alcohol solvents with 1 to 18 carbon atoms, such as isopropanol, 4-methyl-2-pentanol, 3-methoxybutanol, n-hexanol, 2-ethylhexanol, furfuryl alcohol, cyclohexanol, 3,3,5-trimethylcyclohexanol, and diacetone alcohol; Polyol solvents with 2 to 18 carbon atoms, such as ethylene glycol, 1,2-propanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol; Polyol partial ether solvents, etc., are formed by etherifying a portion of the hydroxyl groups in the polyol solvent.

[0148] Examples of ether-based solvents include: Dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether; Tetrahydrofuran, tetrahydropyran, and other cyclic ether solvents; Ether solvents containing aromatic rings, such as diphenyl ether and anisole (methyl phenyl ether); Polyol ether solvents, etc., are formed by etherifying the hydroxyl groups of the polyol solvent.

[0149] Examples of ketone solvents include: acetone, butanone, methyl isobutyl ketone, and other chain-like ketone solvents. Cyclopentanone, cyclohexanone, methylcyclohexanone, and other cyclic ketone solvents; 2,4-Pentanedione, acetone, acetophenone, etc.

[0150] Examples of amide-based solvents include cyclic amide solvents such as N,N'-dimethylimidazolidineone and N-methylpyrrolidone. N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionic acid and other chain acetamide solvents.

[0151] Examples of ester-based solvents include: Monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate; Diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate are polyol partial ether acetate solvents; Lactone solvents such as γ-butyrolactone and valproic acid; Diethyl carbonate, ethyl carbonate, propyl carbonate, and other carbonate solvents; Solvents such as propylene glycol diacetate, methoxytriethylene glycol acetate, diethyl oxalate, ethyl acetate, ethyl lactate, and diethyl phthalate are polycarboxylic acid diesters.

[0152] Examples of hydrocarbon solvents include: aliphatic hydrocarbon solvents such as n-hexane, cyclohexane, and methylcyclohexane; Aromatic hydrocarbon solvents such as benzene, toluene, diisopropylbenzene, and n-pentylnaphthalene.

[0153] Among these, ester-based solvents and ketone-based solvents are preferred, more preferably polyol partial ether acetate-based solvents, cyclic ketone-based solvents, and lactone-based solvents, and even more preferably propylene glycol monomethyl ether acetate, cyclohexanone, and γ-butyrolactone. The radiosensitive linear resin composition may also contain one or more solvents.

[0154] (Other arbitrary ingredients) In addition to the aforementioned components, the radiosensitive linear resin composition may also contain any other arbitrary components. Examples of such other arbitrary components include: crosslinking agents, accelerators for partial crosslinking, surfactants, compounds containing alicyclic skeletons, sensitizers, etc. One or more of these other arbitrary components may be used individually or in combination.

[0155] <Preparation Method of Radiation-Inducing Linear Resin Composition> The radiosensitive linear resin composition can be prepared, for example, by mixing an onium salt compound (1), a resin, a radiosensitive linear acid generator, a high-fluorine content resin as needed, and a solvent in a specified ratio. Preferably, the radiosensitive linear resin composition is filtered, for example, using a filter with a pore size of approximately 0.05 μm to 0.2 μm after mixing. The solid content concentration of the radiosensitive linear resin composition is typically 0.1% to 50% by mass, preferably 0.5% to 30% by mass, and more preferably 1% to 20% by mass.

[0156] <Pattern Formation Methods> A pattern forming method according to one embodiment of the present invention includes: Step (1) (hereinafter also referred to as the "resist film formation step") involves directly or indirectly coating the radiosensitive linear resin composition onto the substrate to form a resist film; Step (2) (hereinafter also referred to as the "exposure step") involves exposing the resist film to light; and Step (3) (hereinafter also referred to as the "development step") involves developing the exposed resist film.

[0157] According to the resist pattern forming method, high-quality resist patterns can be formed by using the radiosensitive linear resin composition with excellent sensitivity or CDU performance and LWR performance in the exposure step. The steps are described below.

[0158] [Resist Film Formation Steps] In this step (step (1)), a resist film is formed using the aforementioned radiosensitive linear resin composition. Examples of substrates for forming the resist film include, for example, silicon wafers, silicon dioxide, and aluminum-coated wafers, as previously known. Alternatively, organic or inorganic antireflective films disclosed in, for example, Japanese Patent Publication No. 6-12452 or Japanese Patent Publication No. 59-93448 may be formed on the substrate. Examples of coating methods include, for example, spin coating, cast coating, and roll coating. Pre-baking (PB) may be performed after coating as needed to allow the solvent in the coating to evaporate. The PB temperature is typically 60°C to 140°C, preferably 80°C to 120°C. The PB time is typically 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds. The thickness of the formed resist film is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.

[0159] In the case of immersion exposure, regardless of the presence or absence of water-repellent polymer additives such as high-fluorine-content resins in the radiosensitive linear resin composition, a immersion protective film that is insoluble in the immersion liquid can be provided on the formed resist film to avoid direct contact between the immersion liquid and the resist film. As the immersion protective film, either a solvent-removable protective film that is peeled off with a solvent before the development step (e.g., see Japanese Patent Application Laid-Open No. 2006-227632) or a developer-removable protective film that is peeled off simultaneously with the development step (e.g., see WO2005-069076 and WO2006-035790) can be used. From the viewpoint of yield, a developer-removable immersion protective film is preferred.

[0160] In addition, when using radiation with a wavelength of less than 50 nm for the exposure step as the next step, it is preferable to use a resin having the structural unit (I) and structural unit (IV) as the base resin in the composition.

[0161] [Exposure Steps] In this step (step (2)), the resist film formed in step (1), i.e., the resist film formation step), is exposed to radiation by a photomask (which may be immersed in a liquid medium such as water). The radiation used for exposure 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, depending on the linewidth of the target pattern. Among these, far ultraviolet light, electron beams, and EUV are preferred; more preferably, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), electron beams, and EUV; and even more preferably, electron beams and EUV with wavelengths below 50 nm, which are positioned as next-generation exposure technologies.

[0162] When exposure is performed by immersion exposure, the immersion solution used can be, for example, water or a fluorine-based inactive liquid. Preferably, the immersion solution is a liquid that is transparent to the exposure wavelength and has a temperature coefficient of refractive index that is as small as possible to minimize distortion of the optical image projected onto the film. Especially when the exposure light source is ArF excimer laser light (wavelength 193 nm), water is preferred in terms of ease of acquisition and ease of operation, based on the above considerations. When using water, an additive that reduces the surface tension of water and increases interfacial activity can be added in a small proportion. This additive is preferably one that does not dissolve the resist film on the wafer and has a negligible effect on the optical coating on the lower surface of the lens. Distilled water is preferred as the water used.

[0163] Preferably, a post-exposure bake (PEB) is performed after the exposure, in which the acid generated by the self-induced radioactive linear acid generator during exposure promotes the dissociation of acid-dissociating groups in the resin or the like. This PEB creates a difference in solubility of the developer between the exposed and unexposed areas. The PEB temperature is typically 50°C to 180°C, preferably 80°C to 130°C. The PEB time is typically 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[0164] [Developing Steps] In this step (step (3)), the resist film exposed in step (2), i.e., the exposure step, is developed. This forms a predetermined resist pattern. Generally, after development, the film is rinsed with a solution such as water or alcohol and then dried.

[0165] As a developing solution for the aforementioned development, in the case of alkaline development, examples include alkaline aqueous solutions containing 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, methyl diethylamine, ethyl dimethylamine, triethanolamine, tetramethyl ammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene. Among these, an aqueous solution of TMAH is preferred, and a 2.38% by mass aqueous solution of TMAH is more preferred.

[0166] In addition, when developing with organic solvents, examples include: hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, alcohol solvents, and other organic solvents, or solvents containing organic solvents. Examples of such organic solvents include one or more solvents listed as solvents for the composition of the radiosensitive linear resin. Among these, ether solvents, ester solvents, and ketone solvents are preferred. As an ether solvent, a glycol ether solvent is preferred, more preferably ethylene glycol monomethyl ether or propylene glycol monomethyl ether. As an ester solvent, an acetate solvent is preferred, more preferably n-butyl acetate or amyl acetate. As a ketone solvent, a chain ketone is preferred, more preferably 2-heptanone. The content of organic solvent in the developing solution is preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 99% by mass or more. Other components in the developer besides the organic solvent include, for example, water and silicone oil.

[0167] As described above, the developer can be any of an alkaline developer or an organic solvent developer, but it is preferred that the developer contains an organic solvent, and the resulting pattern is a negative pattern.

[0168] Examples of development methods include: immersing a substrate in a tank filled with developer for a fixed time (immersion method); developing a substrate by using surface tension to accumulate developer on the substrate surface and then holding it there for a fixed time (puddle method); spraying developer onto the substrate surface (spraying method); and continuously applying developer onto a substrate rotating at a fixed speed while scanning the developer application nozzle at a fixed speed (dynamic distribution method).

[0169] <Onium salt compound(1)> In another embodiment of the present invention, the onium salt compound is represented by the formula (1).

[0170] As the onnnage salt compound represented by formula (1) in this embodiment, the onnnage salt compound (1) contained in the radiosensitive linear resin composition can preferably be used. [Example]

[0171] The present invention will now be described in detail based on embodiments, but the present invention is not limited to these embodiments. Methods for determining various physical properties are shown below.

[0172] [Weight-average molecular weight (Mw) and number-average molecular weight (Mn)] The Mw and Mn of the polymer were determined under the aforementioned conditions. Furthermore, the dispersity (Mw / Mn) was calculated based on the results of the Mw and Mn measurements.

[0173] [13C-Nuclear Magnetic Resonance (NMR) Analysis] The 13C-NMR analysis of the polymer was performed using a nuclear magnetic resonance apparatus (JNM-Delta400 of NEC Corporation).

[0174] Synthesis of Resins and High-Fluoride Resins The following shows the monomers used in the synthesis of each resin and high-fluorine-content resin in each embodiment and comparative example. Furthermore, in the following synthesis examples, unless otherwise specified, parts by mass refers to the value when the total mass of the monomers used is set to 100 parts by mass, and moles% refers to the value when the total number of moles of the monomers used is set to 100 moles%.

[0175] [Chemistry 20]

[0176] [Synthesis example 1] (Synthesis of resin (A-1)) Monomers (M-1), (M-2), and (M-13) were dissolved in 200 parts by mass of 2-butanone at a mole ratio of 40 / 15 / 45 (moles%). Azobisisobutyronitrile (AIBN) (3 moles relative to the total 100 moles of the monomers used) was added as an initiator to prepare a monomer solution. 100 parts by mass of 2-butanone were placed in a reaction vessel, purged with nitrogen for 30 minutes, and the reaction vessel was set to 80°C. The monomer solution was added dropwise over 3 hours with stirring. The start of the dropwise addition was defined as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After the polymerization reaction was completed, the polymerization solution was water-cooled to below 30°C. The cooled polymerization solution was then added to methanol (2,000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with methanol, filtered again, and dried at 50°C for 24 hours to obtain a white powdery resin (A-1) (yield: 83%). The Mw of resin (A-1) was 8,800, and the Mw / Mn ratio was 1.50. Furthermore, 13C-NMR analysis showed that the contents of each structural unit derived from (M-1), (M-2), and (M-13) were 41.3 mol%, 13.8 mol%, and 44.9 mol, respectively.

[0177] [Synthesis Example 2~Synthesis Example 11] (Synthesis of resins (A-2) to (A-11)) Except for the monomers of the types and proportions shown in Table 1 below, resins (A-2) to (A-11) were synthesized in the same manner as in Synthesis Example 1. The content ratio (moles%), yield (%), and physical property values ​​(Mw and Mw / Mn) of each structural unit of the obtained resins are shown in Table 1 below. Furthermore, "-" in Table 1 below indicates that the corresponding monomer was not used (the same applies to subsequent tables).

[0178] [Table 1] [A] Resin Provides a single volume of structural unit (I) Provides a single volume of structural unit (II) Provides a single volume of structural unit (III) Mw Mw / Mn type Mixing ratio (mol%) Structural unit Contains proportion (mol%) type Mixing ratio (mol%) Structural unit Contains proportion (mol%) type Mixing ratio (mol%) Structural unit Contains proportion (mol%) Synthesis example 1 A-1 M-1 40 41.3 M-13 45 44.9 - - - 8800 1.50 M-2 15 13.8 Synthesis example 2 A-2 M-1 30 31.4 M-6 60 60.6 - - - 9000 1.44 M-2 10 8.0 Synthesis example 3 A-3 M-1 30 31.9 M-5 60 61.7 - - - 8900 1.39 M-3 10 6.4 Synthesis example 4 A-4 M-1 35 32.3 M-12 45 49.6 - - - 8000 1.56 M-3 20 18.1 Synthesis example 5 A-5 M-1 40 41.1 M-10 45 45.7 - - - 8700 1.44 M-4 15 13.2 Synthesis example 6 A-6 M-1 40 41.6 M-11 45 46.1 - - - 7700 1.51 M-4 15 12.3 Synthesis Example 7 A-7 M-1 40 42.4 M-10 45 39.5 M-14 15 18.1 7800 1.59 Synthesis example 8 A-8 M-1 40 41.1 M-7 40 35.7 M-15 20 23.2 8500 1.61 Synthesis example 9 A-9 M-1 50 51.0 M-8 50 49.0 - - - 7800 1.55 Synthesis example 10 A-10 M-1 40 44.4 M-9 60 55.6 - - - 7900 1.59 Synthesis example 11 A-11 M-1 40 42.8 M-6 60 57.2 - - - 8000 1.43

[0179] [Synthesis Example 12] (Synthesis of resin (A-12)) Monomers (M-1) and (M-18) were dissolved in 1-methoxy-2-propanol (200 parts by mass) at a molar ratio of 50 / 50 (molar%), and AIBN (5 molar%) was added as an initiator to prepare a monomer solution. 1-methoxy-2-propanol (100 parts by mass) was placed in a reaction vessel, purged with nitrogen for 30 minutes, and the reaction vessel was set to 80°C. The monomer solution was added dropwise over 3 hours with stirring. The start of the dropwise addition was defined as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After the polymerization reaction was completed, the polymerization solution was water-cooled to below 30°C. The cooled polymerization solution was added to hexane (2,000 parts by mass), and the precipitated white powder was filtered and separated. The filtered white powder was washed twice with hexane, filtered again, and dissolved in 1-methoxy-2-propanol (300 parts by mass). Subsequently, methanol (500 parts by mass), triethylamine (50 parts by mass), and ultrapure water (10 parts by mass) were added, and a hydrolysis reaction was carried out at 70°C for 6 hours with stirring. After the reaction was completed, the residual solvent was removed by distillation, and the obtained solid was dissolved in acetone (100 parts by mass) and added dropwise to water (500 parts by mass) to solidify the resin. The obtained solid was separated by filtration and dried at 50°C for 13 hours to obtain a white powdery resin (A-12) (yield: 79%). The Mw of resin (A-12) was 5,200, and the Mw / Mn ratio was 1.60. In addition, the 13C-NMR analysis results showed that the contents of each structural unit derived from (M-1) and (M-18) were 51.3 mol% and 48.7 mol%, respectively.

[0180] [Synthesis Example 13~Synthesis Example 15] (Synthesis of resins (A-13) to (A-15)) Except for the monomers of the types and proportions shown in Table 2 below, resins (A-13) to (A-15) were synthesized in the same manner as in Synthesis Example 12. The content ratio (moles%), yield (%), and physical property values ​​(Mw and Mw / Mn) of each structural unit of the obtained resins are shown in Table 2 below.

[0181] [Table 2] [A] Resin Provides a single volume of structural unit (I) Provides a single volume of structural unit (III) Provides a single volume of structural unit (IV) Mw Mw / Mn type Mixing ratio (mol%) Structural unit Contains proportion (mol%) type Mixing ratio (mol%) Structural unit Contains proportion (mol%) type Mixing ratio (mol%) Structural unit Contains proportion (mol%) Synthesis example 12 A-12 M-1 50 51.3 - - - M-18 50 48.7 5200 1.60 Synthesis example 13 A-13 M-3 50 46.6 M-14 10 11.1 M-19 40 42.3 5600 1.55 Synthesis example 14 A-14 M-2 50 48.1 M-17 20 21.3 M-18 30 30.6 5100 1.59 Synthesis Example 15 A-15 M-1 55 55.7 M-17 15 15.1 M-19 30 29.2 6100 1.50

[0182] [Synthesis Example 16] (Synthesis of high-fluoride resin (E-1)) Monomers (M-1) and (M-20) were dissolved in 200 parts by mass of 2-butanone at a molar ratio of 20 / 80 (mol%), and AIBN (4 mol%) was added as an initiator to prepare a monomer solution. 100 parts by mass of 2-butanone was placed in a reaction vessel, purged with nitrogen for 30 minutes, and the reaction vessel was set to 80°C. The monomer solution was added dropwise over 3 hours with stirring. The start of the dropwise addition was defined as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After the polymerization reaction was completed, the polymerization solution was water-cooled and cooled to below 30°C. After replacing the solvent with acetonitrile (400 parts by mass), hexane (100 parts by mass) was added, stirred, and the acetonitrile layer was recovered. This process was repeated three times. By replacing the solvent with propylene glycol monomethyl ether acetate, a solution of high-fluorine resin (E-1) was obtained (yield: 69%). The high-fluorine content resin (E-1) has a Mw of 6,000 and an Mw / Mn ratio of 1.62. Furthermore, 13C-NMR analysis showed that the content of each structural unit derived from (M-1) and (M-20) was 19.9 mol% and 80.1 mol%, respectively.

[0183] [Synthesis Example 17~Synthesis Example 20] (Synthesis of high-fluorine content resins (E-2) to high-fluorine content resins (E-5)) Except for the single-unit polymers of the types and proportions shown in Table 3 below, high-fluorine content resins (E-2) to (E-5) were synthesized in the same manner as in Synthesis Example 16. The content ratio (moles%), yield (%), and physical properties (Mw and Mw / Mn) of each structural unit of the obtained high-fluorine content resins are shown in Table 3 below.

[0184] [Table 3] [E] High fluorine content resin Provide a single volume of structural unit (V) or structural unit (VI). Provides a single volume of structural unit (I) Provides a single volume of structural unit (III) Provide single volume for other structural units Mw Mw / Mn type Mixing ratio (mol%) Structural unit Contains proportion (mol%) type Mixing ratio (mol%) Structural unit Contains proportion (mol%) type Mixing ratio (mol%) Structural unit Contains proportion (mol%) type Mixing ratio (mol%) Structural unit Contains proportion (mol%) Synthesis example 16 E-1 M-20 80 80.1 M-1 20 19.9 - - - - - - 6000 1.62 Synthesis Example 17 E-2 M-21 80 81.9 M-1 20 18.1 - - - - - - 7200 1.77 Synthesis Example 18 E-3 M-22 60 62.3 - - - - - - M-16 40 38.7 6300 1.82 Synthesis Example 19 E-4 M-22 70 68.7 - - - M-14 30 31.3 - - - 6500 1.81 Synthesis example 20 E-5 M-20 60 59.2 M-2 10 10.3 M-17 30 30.5 - - - 6100 1.86

[0185] Synthesis of Onium Salts [Synthesis Example 21] (Synthesis of onium salt compound (C-1)) The onium salt compound (C-1) was synthesized according to the following synthetic procedure.

[0186] [Chemistry 21]

[0187] 20.0 mmol of 6-bromo-5,5,6,6-tetrafluorohexane-1-ol, 30.0 mmol of 1-(terbutoxycarbonyl)-4-piperidinecarboxylic acid, 30.0 mmol of dicyclohexylcarbodiimide, and 50 g of dichloromethane were added to a reaction vessel and stirred at room temperature for 4 hours. After dilution with water, extraction with dichloromethane was performed, and the organic layer was separated. The obtained organic layer was washed successively with saturated sodium chloride aqueous solution and water. After drying with sodium sulfate, the solvent was removed by distillation, and the solution was purified by column chromatography to obtain the bromide in good yield.

[0188] A 1 M solution was prepared by adding an acetonitrile:water mixture (1:1 mass ratio) to the bromide, followed by the addition of 40.0 mmol of sodium dithionite and 60.0 mmol of sodium bicarbonate, and reacted at 70°C for 4 hours. Extraction was performed using acetonitrile, and the solvent was removed by distillation. A 0.5 M solution was then prepared by adding an acetonitrile:water mixture (3:1 mass ratio). 60.0 mmol of hydrogen peroxide solution and 2.00 mmol of sodium tungstate were added, and the mixture was heated and stirred at 50°C for 12 hours. Extraction was performed using acetonitrile, and the solvent was removed by distillation, thereby obtaining a sodium sulfonate compound. 20 mmol of triphenylstrontium bromide was added to the sodium sulfonate compound, followed by the addition of a water:dichloromethane mixture (1:3 mass ratio) to prepare a 0.5 M solution. After vigorous stirring at room temperature for 3 hours, extraction was performed using dichloromethane, and the organic layer was separated. After drying the obtained organic layer with sodium sulfate, the solvent was removed by distillation and purified by column chromatography, thereby obtaining the onium salt compound (C-1) represented by the formula (C-1) in good yield.

[0189] [Synthesis Example 22~Synthesis Example 44] (Synthesis of compounds (C-2) to (C-24)) Except for appropriate changes to the raw materials and precursors, the onium salts represented by the following formulas (C-2) to (C-24) were synthesized in the same manner as in Synthesis Example 21.

[0190] [Chemistry 22]

[0191] [Onium salts other than onium salts (C-1) to onium salts (C-24)] cc-1~cc-12: Onium salt compounds represented by the following formulas (cc-1) to (cc-12) (hereinafter, the onium salt compounds represented by formulas (cc-1) to (cc-12) are sometimes referred to as "onium salt compound (cc-1)" to "compound (cc-12)" respectively).

[0192] [Chemistry 23]

[0193] [B]Radiosensitive linear acid generator B-1 to B-6: Compounds represented by formulas (B-1) to (B-6) below (hereinafter, the compounds represented by formulas (B-1) to (B-6) are sometimes referred to as "Compound (B-1)" to "Compound (B-6)" respectively).

[0194] [Chemistry 24]

[0195] [[D]solvent] D-1: Propylene glycol monomethyl ether acetate D-2: Propylene glycol monomethyl ether D-3: γ-Butyrolactone D-4: Ethyl lactate

[0196] [Preparation of positive-type radiosensitive linear resin composition for ArF exposure] [Example 1] A mixture of 100 parts by mass of (A-1) as [A] resin, 12.0 parts by mass of (B-1) as [B] radiosensitive linear acid generator, 5.0 parts by mass of (C-1) as [C] acid diffusion control agent, 3.0 parts by mass of (E-1) as [E] high fluoride content resin (solid component), and 3,230 parts by mass of a mixed solvent of (D-1) / (D-2) / (D-3) as [D] solvent was filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiosensitive linear resin composition (J-1).

[0197] [Examples 2-51 and Comparative Examples 1-12] Except for the types and amounts of each component shown in Table 4 below, radiosensitive linear resin compositions (J-2) to (J-51) and radiosensitive linear resin compositions (CJ-1) to (CJ-12) were prepared in the same manner as in Example 1.

[0198] [Table 4] Radiation-sensitive linear resin composition [A] Resin [B] Radiosensitive linear acid generator [C] Acid diffusion control agent [E] High fluorine content resin [D] Solvent type content (parts by weight) type content (parts by weight) type content (parts by weight) type content (parts by weight) type content (parts by weight) Example 1 J-1 A-1 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 2 J-2 A-1 100 B-1 12.0 C-2 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 3 J-3 A-1 100 B-1 12.0 C-3 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 4 J-4 A-1 100 B-1 12.0 C-4 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 5 J-5 A-1 100 B-1 12.0 C-5 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 6 J-6 A-1 100 B-1 12.0 C-6 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 7 J-7 A-1 100 B-1 12.0 C-7 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 8 J-8 A-1 100 B-1 12.0 C-8 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 9 J-9 A-1 100 B-1 12.0 C-9 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 10 J-10 A-1 100 B-1 12.0 C-10 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 11 J-11 A-1 100 B-1 12.0 C-11 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 12 J-12 A-1 100 B-1 12.0 C-12 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 13 J-13 A-1 100 B-1 12.0 C-13 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 14 J-14 A-1 100 B-1 12.0 C-14 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 15 J-15 A-1 100 B-1 12.0 C-15 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 16 J-16 A-1 100 B-1 12.0 C-16 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 17 J-17 A-1 100 B-1 12.0 C-17 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 18 J-18 A-1 100 B-1 12.0 C-18 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 19 J-19 A-1 100 B-1 12.0 C-19 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 20 J-20 A-1 100 B-1 12.0 C-20 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 21 J-21 A-1 100 B-1 12.0 C-21 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 22 J-22 A-1 100 B-1 12.0 C-22 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 23 J-23 A-1 100 B-1 12.0 C-23 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 24 J-24 A-1 100 B-1 12.0 C-24 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 25 J-25 A-2 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 26 J-26 A-3 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 27 J-27 A-4 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 28 J-28 A-5 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 29 J-29 A-6 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 30 J-30 A-7 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 31 J-31 A-8 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 32 J-32 A-9 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 33 J-33 A-10 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 34 J-34 A-11 100 B-1 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 35 J-35 A-1 100 B-2 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 36 J-36 A-1 100 B-3 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 37 J-37 A-1 100 B-4 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 38 J-38 A-1 100 B-5 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 39 J-39 A-1 100 B-6 12.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 40 J-40 A-1 100 B-1 12.0 C-1 5.0 E-2 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 41 J-41 A-1 100 B-1 12.0 C-1 5.0 E-3 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 42 J-42 A-1 100 B-1 12.0 C-1 5.0 E-4 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 43 J-43 A-1 100 B-1 12.0 C-1 1.5 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 44 J-44 A-1 100 B-1 12.0 C-1 8.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 45 J-45 A-1 100 B-1 12.0 C-1 12.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 46 J-46 A-1 100 B-1 12.0 C-1 / cc-1 2.5 / 2.5 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 47 J-47 A-1 100 B-1 12.0 C-1 / cc-2 2.5 / 2.5 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 48 J-48 A-1 100 B-1 12.0 C-2 / cc-5 2.5 / 2.5 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 49 J-49 A-1 100 B-1 / B-3 6.0 / 6.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 50 J-50 A-1 100 B-1 / B-5 6.0 / 6.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Example 51 J-51 A-1 100 B-1 / B-6 6.0 / 6.0 C-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 1 CJ-1 A-1 100 B-1 12.0 cc-1 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 2 CJ-2 A-1 100 B-1 12.0 cc-2 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 3 CJ-3 A-1 100 B-1 12.0 cc-3 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 4 CJ-4 A-1 100 B-1 12.0 cc-4 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 5 CJ-5 A-1 100 B-1 12.0 cc-5 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 6 CJ-6 A-1 100 B-1 12.0 cc-6 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 7 CJ-7 A-1 100 B-1 12.0 cc-7 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 8 CJ-8 A-1 100 B-1 12.0 cc-8 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 9 CJ-9 A-1 100 B-1 12.0 cc-9 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 10 CJ-10 A-1 100 B-1 12.0 cc-10 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 11 CJ-11 A-1 100 B-1 12.0 cc-11 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30 Comparative Example 12 CJ-12 A-1 100 B-1 12.0 cc-12 5.0 E-1 3.0 D-1 / D-2 / D-3 2240 / 960 / 30

[0199] <Formation of resist patterns using ArF exposure with positive-type radiosensitive linear resin composition> Using a spin coater (Tokyo Electron's "CLEAN TRACK ACT12"), a lower antireflective film forming composition (Brewer Science's "ARC66") was coated onto a 12-inch silicon wafer, followed by heating at 205°C for 60 seconds to form a lower antireflective film with an average thickness of 100 nm. The prepared ArF exposure positive-type linear photosensitive resin composition was then coated onto this lower antireflective film using the same spin coater and pre-baked at 100°C for 60 seconds (PB). Afterward, it was cooled at 23°C for 30 seconds to form a resist film with an average thickness of 90 nm. Next, the resist film was exposed using an ArF excimer laser immersion exposure system (ASML's "TWINSCAN XT-1900i") with optical conditions of NA=1.35 and dipole (σ=0.9 / 0.7) to create a mask pattern separating 40 nm lines and space. After exposure, it was baked at 100°C for 60 seconds (PEB). Subsequently, the resist film was alkaline developed using a 2.38% by mass TMAH aqueous solution as an alkaline developer. After development, it was rinsed with water and then dried to form a positive resist pattern (40 nm lines and space pattern).

[0200] <Evaluation> The sensitivity and LWR performance of the resist pattern formed using the ArF exposure positive-type radiosensitive linear resin composition were evaluated according to the following method. The results are shown in Table 5 below. Furthermore, the length of the resist pattern was measured using a scanning electron microscope (Hitachi High-Technologies, Inc.'s "CG-5000").

[0201] [sensitivity] In the formation of resist patterns using the ArF exposure positive-type radiosensitive linear resin composition, the exposure amount for forming 40 nm lines and spatial patterns is set as the optimal exposure amount, and this optimal exposure amount is set as the sensitivity (mJ / cm²). Regarding sensitivity, conditions below 25 mJ / cm² are evaluated as "good," and conditions exceeding 25 mJ / cm² are evaluated as "poor."

[0202] [LWR Performance] A 40 nm line-space resist pattern was formed by irradiating the area with the optimal exposure determined in the sensitivity evaluation. The resist pattern was observed from above using a scanning electron microscope. The linewidth deviation at a total of 500 points was measured, and a 3-sigma value was determined based on the distribution of these measurements. This 3-sigma value was set as LWR (nm). A smaller LWR value indicates lower and better line roughness. Regarding LWR performance, conditions below 3.0 nm were evaluated as "good," and conditions exceeding 3.0 nm were evaluated as "poor."

[0203] [Table 5] Radiation-sensitive linear resin composition Sensitivity (mJ / cm 2) LWR (nm) Example 1 J-1 20 2.5 Example 2 J-2 twenty four 2.8 Example 3 J-3 20 2.4 Example 4 J-4 twenty two 2.3 Example 5 J-5 twenty three 2.7 Example 6 J-6 twenty three 2.8 Example 7 J-7 twenty three 2.7 Example 8 J-8 20 2.4 Example 9 J-9 twenty one 2.6 Example 10 J-10 19 2.6 Example 11 J-11 twenty three 2.7 Example 12 J-12 twenty three 2.6 Example 13 J-13 19 2.8 Example 14 J-14 18 2.9 Example 15 J-15 twenty one 2.5 Example 16 J-16 twenty two 2.7 Example 17 J-17 twenty three 2.5 Example 18 J-18 twenty two 2.5 Example 19 J-19 twenty four 2.9 Example 20 J-20 19 2.1 Example 21 J-21 twenty two 2.6 Example 22 J-22 twenty three 2.8 Example 23 J-23 twenty two 2.5 Example 24 J-24 twenty two 2.7 Example 25 J-25 19 2.3 Example 26 J-26 twenty one 2.3 Example 27 J-27 20 2.4 Example 28 J-28 20 2.6 Example 29 J-29 19 2.5 Example 30 J-30 twenty two 2.5 Example 31 J-31 20 2.3 Example 32 J-32 19 2.4 Example 33 J-33 19 2.8 Example 34 J-34 20 2.3 Example 35 J-35 18 2.7 Example 36 J-36 19 2.8 Example 37 J-37 twenty four 2.7 Example 38 J-38 19 2.3 Example 39 J-39 19 2.3 Example 40 J-40 20 2.5 Example 41 J-41 20 2.5 Example 42 J-42 twenty one 2.5 Example 43 J-43 18 2.7 Example 44 J-44 twenty one 2.8 Example 45 J-45 twenty four 2.6 Example 46 J-46 18 2.7 Example 47 J-47 twenty three 2.5 Example 48 J-48 twenty three 2.6 Example 49 J-49 19 2.3 Example 50 J-50 18 2.7 Example 51 J-51 18 2.4 Comparative Example 1 CJ-1 27 3.5 Comparative Example 2 CJ-2 33 3.2 Comparative Example 3 CJ-3 36 3.7 Comparative Example 4 CJ-4 27 3.4 Comparative Example 5 CJ-5 28 3.6 Comparative Example 6 CJ-6 35 4.0 Comparative Example 7 CJ-7 36 4.2 Comparative Example 8 CJ-8 26 3.2 Comparative Example 9 CJ-9 27 3.3 Comparative Example 10 CJ-10 32 4.0 Comparative Example 11 CJ-11 29 3.9 Comparative Example 12 CJ-12 26 3.2

[0204] As is evident from the results in Table 5, the radiosensitive linear resin composition of the embodiments exhibits good sensitivity and LWR performance when used for ArF exposure, whereas the comparative examples show inferior characteristics compared to the embodiments. Therefore, when the radiosensitive linear resin composition of the embodiments is used for ArF exposure, resist patterns with good LWR performance can be formed with high sensitivity.

[0205] [Preparation of positive-type radiosensitive linear resin compositions for extreme ultraviolet (EUV) exposure] [Example 52] A mixture of 100 parts by mass of (A-12) as [A] resin, 15.0 parts by mass of (B-1) as [B] radiosensitive linear acid generator, 3.0 parts by mass of (C-1) as [C] acid diffusion control agent, 3.0 parts by mass of (E-5) as [E] high fluoride content resin (solid component), and 6,110 parts by mass of a mixed solvent of (D-1) / (D-4) as [D] solvent was filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiosensitive linear resin composition (J-52).

[0206] [Examples 53-62 and Comparative Examples 13-16] Except for the types and amounts of each component shown in Table 6 below, the radiosensitive linear resin compositions (J-53) to (J-62) and (CJ-13) to (CJ-16) were prepared in the same manner as in Example 52.

[0207] [Table 6] Radiation-sensitive linear resin composition [A] Resin [B] Radiosensitive linear acid generator [C] Acid diffusion control agent [E] High fluorine content resin [D] Solvent type content (parts by weight) type content (parts by weight) type content (parts by weight) type content (parts by weight) type content (parts by weight) Example 52 J-52 A-12 100 B-1 15.0 C-1 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Example 53 J-53 A-12 100 B-1 15.0 C-3 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Example 54 J-54 A-12 100 B-1 15.0 C-6 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Example 55 J-55 A-12 100 B-1 15.0 C-11 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Example 56 J-56 A-12 100 B-1 15.0 C-20 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Example 57 J-57 A-13 100 B-1 15.0 C-1 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Example 58 J-58 A-14 100 B-1 15.0 C-1 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Example 59 J-59 A-15 100 B-1 15.0 C-1 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Example 60 J-60 A-12 100 B-4 15.0 C-1 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Example 61 J-61 A-12 100 B-5 15.0 C-1 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Example 62 J-62 A-12 100 B-6 15.0 C-1 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Comparative Example 13 CJ-13 A-12 100 B-1 15.0 cc-2 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Comparative Example 14 CJ-14 A-12 100 B-1 15.0 cc-5 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Comparative Example 15 CJ-15 A-12 100 B-1 15.0 cc-8 3.0 E-5 3.0 D-1 / D-4 4280 / 1830 Comparative Example 16 CJ-16 A-12 100 B-1 15.0 cc-12 3.0 E-5 3.0 D-1 / D-4 4280 / 1830

[0208] Formation of resist patterns using EUV exposure with positive-type radiosensitive linear resin compositions Using a spin coater (Tokyo Electron's "CLEAN TRACK ACT12"), a lower antireflective film forming composition (Brewer Science's "ARC66") was coated onto a 12-inch silicon wafer, and then heated at 205°C for 60 seconds to form a lower antireflective film with an average thickness of 105 nm. The prepared EUV exposure-sensitive linear resin composition was then coated onto this lower antireflective film using the same spin coater and subjected to a photopolymerization process (PB) at 130°C for 60 seconds. Afterward, it 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, the resist film was subjected to PEB treatment at 120°C for 60 seconds. Subsequently, the resist film was alkaline developed using a 2.38% by mass TMAH aqueous solution as an 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).

[0209] <Evaluation> The sensitivity and LWR performance of the resist pattern formed using the aforementioned positive-type linear resin composition for EUV exposure were evaluated according to the following method. The results are shown in Table 7 below. Furthermore, the length of the resist pattern was measured using a scanning electron microscope (Hitachi High-Technologies, Inc.'s "CG-5000").

[0210] [sensitivity] In forming the resist pattern using the aforementioned positive-type linear resin composition for EUV exposure, the exposure amount for forming the 32 nm line and spatial pattern is set as the optimal exposure amount, and this optimal exposure amount is set as the sensitivity (mJ / cm²). Regarding sensitivity, a value below 30 mJ / cm² is evaluated as "good," and a value exceeding 30 mJ / cm² is evaluated as "poor."

[0211] [LWR Performance] The optimal exposure, determined in the sensitivity evaluation, was used to adjust the mask size to form a 32 nm line and spatial pattern, thus creating a resist pattern. The resist pattern was observed from above using a scanning electron microscope. Linewidth deviations at a total of 500 points were measured, and a 3-sigma value was determined based on the distribution of these measurements. This 3-sigma value was set as LWR (nm). A smaller LWR value indicates less line wobble and better performance. Regarding LWR performance, values ​​below 3.0 nm were rated as "good," and values ​​above 3.0 nm were rated as "poor."

[0212] [Table 7] Radiation-sensitive linear resin composition Sensitivity (mJ / cm 2) LWR (nm) Example 52 J-52 26 2.6 Example 53 J-53 twenty four 2.3 Example 54 J-54 27 2.4 Example 55 J-55 27 2.8 Example 56 J-56 28 2.7 Example 57 J-57 25 2.3 Example 58 J-58 twenty four 2.4 Example 59 J-59 27 2.3 Example 60 J-60 28 2.7 Example 61 J-61 twenty three 2.5 Example 62 J-62 twenty four 2.5 Comparative Example 13 CJ-13 32 3.4 Comparative Example 14 CJ-14 33 3.8 Comparative Example 15 CJ-15 31 3.3 Comparative Example 16 CJ-16 32 3.5

[0213] As is evident from the results in Table 7, the radiosensitive linear resin composition of the Examples exhibits good sensitivity and LWR performance when used for EUV exposure, whereas the Comparative Examples show inferior characteristics compared to the Examples.

[0214] [Preparation of negative-type radiosensitive linear resin composition for ArF exposure, formation and evaluation of resist patterns using this composition] [Example 63] A mixture of 100 parts by mass of (A-6) as [A] resin, 10.0 parts by mass of (B-5) as [B] radiosensitive linear acid generator, 4.0 parts by mass of (C-1) as [C] acid diffusion control agent, 1.0 parts by mass of (E-4) as [E] high fluorine content resin (solid component), and 3,230 parts by mass of a mixed solvent of (D-1) / (D-2) / (D-3) as [D] solvent was filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiosensitive linear resin composition (J-63).

[0215] Using a spin coater (Tokyo Electron's "CLEAN TRACK ACT12"), a lower antireflective film forming composition (Brewer Science's "ARC66") was coated onto a 12-inch silicon wafer, followed by heating at 205°C for 60 seconds to form a lower antireflective film with an average thickness of 100 nm. The prepared ArF exposure negative-type radiosensitive linear resin composition (J-63) was then coated onto this lower antireflective film using the same spin coater and pre-baked at 100°C for 60 seconds (PB). Afterward, it was cooled at 23°C for 30 seconds to form a resist film with an average thickness of 90 nm. Next, the resist film was exposed using an ArF excimer laser immersion exposure system (ASML's "TWINSCAN XT-1900i") with optical conditions of NA=1.35 and annular (σ=0.8 / 0.6), forming a mask pattern with 40 nm apertures and a 105 nm spacing. After exposure, it was baked at 100°C for 60 seconds (PEB). Subsequently, the resist film was developed using n-butyl acetate as an organic solvent and dried to form a negative resist pattern (40 nm apertures, 105 nm spacing).

[0216] <Evaluation> The LWR performance of the resist pattern formed using the ArF exposure negative-type radiosensitive linear resin composition was evaluated according to the following method. Furthermore, the length of the resist pattern was measured using a scanning electron microscope (Hitachi High-Technologies' "CG-5000").

[0217] [CDU Performance] Using the aforementioned scanning electron microscope, the length of a total of 1,800 40 nm apertures with a 105 nm spacing in the resist pattern was measured at any point from the top of the pattern. The dimensional deviation (3σ) was calculated and set as the CDU performance (nm). The smaller the CDU value, the smaller and better the aperture deviation over a long period.

[0218] The resist pattern of the negative radiosensitive linear resin composition for ArF exposure was evaluated as described above. As a result, the radiosensitive linear resin composition of Example 63 showed good LWR performance even when a negative resist pattern was formed using ArF exposure.

[0219] [Preparation of negative-type radiosensitive linear resin composition for EUV exposure, formation and evaluation of resist patterns using this composition] [Example 64] A mixture of 100 parts by mass of (A-13) as [A] resin, 20.0 parts by mass of (B-6) as [B] radiosensitive linear acid generator, 10.0 parts by mass of (C-1) as [C] acid diffusion control agent, 7.0 parts by mass of (E-5) as [E] high fluoride content resin (solid component), and 6,110 parts by mass of a mixed solvent of (D-1) / (D-4) as [D] solvent was filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiosensitive linear resin composition (J-64).

[0220] Using a spin coater (Tokyo Electron's "CLEAN TRACK ACT12"), a lower antireflective film forming composition (Brewer Science's "ARC66") was coated onto a 12-inch silicon wafer, and then heated at 205°C for 60 seconds to form a lower antireflective film with an average thickness of 105 nm. The prepared EUV exposure-sensitive linear resin composition (J-64) was then coated onto this lower antireflective film using the same spin coater and subjected to a photoresist exposure at 130°C for 60 seconds. Afterward, it was cooled at 23°C for 30 seconds to form a photoresist film with an average thickness of 55 nm. Next, the photoresist 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, PEB was applied at 120°C for 60 seconds. Subsequently, the resist film was developed using n-butyl acetate as an organic solvent and dried to form a negative resist pattern (40 nm holes, 105 nm spacing).

[0221] The resist pattern using the EUV exposure negative radiosensitive linear resin composition was evaluated in the same manner as the resist pattern using the ArF exposure negative radiosensitive linear resin composition. As a result, the CDU performance of the radiosensitive linear resin composition of Example 64 was good even when a negative resist pattern was formed using EUV exposure. [Industry availability]

[0222] According to the described method for forming a photosensitive linear resin composition and resist pattern, resist patterns with good sensitivity to exposure light and excellent LWR and CDU performance can be formed. Therefore, these are preferably used in the fabrication processes of semiconductor devices that are expected to be further miniaturized in the future.

[0223] none

Claims

1. A radiosensitive linear resin composition comprising: an onium salt compound represented by formula (1), a resin containing structural units having acid-dissociable groups, a solvent, and a radiosensitive linear acid generator, wherein the radiosensitive linear acid generator generates an acid with a smaller pKa than the acid generated by the onium salt compound upon irradiation with radiation.

1. In formula (1), R1 is a monovalent hydrocarbon group with 1 to 20 carbon atoms; R2 and R3 are each independently a monovalent hydrocarbon group with 1 to 20 carbon atoms, or represent a ring structure with 3 to 20 ring members formed by R2 and R3 bonded together with the carbon atoms thereon; R4 is a hydrogen atom or a monovalent hydrocarbon group with 1 to 20 carbon atoms and L1 is a substituted or unsubstituted alkanediol with 1 to 8 carbon atoms, or represents a ring structure with R4 and L1 bonded together with the carbon atoms thereon. The nitrogen atoms bonded together form a pyrrolidine or piperidine structure; L2 is an unsubstituted divalent chain hydrocarbon group with 1 to 10 carbon atoms; Rf1 and Rf2 are independently fluorine atoms, monovalent hydrocarbon groups with 1 to 10 carbon atoms, or monovalent fluorinated hydrocarbon groups with 1 to 10 carbon atoms, respectively; when multiple Rf1 and Rf2 exist, the multiple Rf1 and Rf2 are the same or different from each other; n is an integer from 1 to 4; Z+ is a monovalent radiosensitive linear ononium cation).

2. The radiosensitive linear resin composition as claimed in claim 1, wherein, In the above formula (1), n ​​is 1 or 2.

3. The radiosensitive linear resin composition as described in claim 1 or claim 2, wherein, In the formula (1), R1, R2 and R3 are each independently a chain hydrocarbon group with 1 to 5 carbon atoms.

4. The radiosensitive linear resin composition as described in claim 1 or claim 2, wherein, The structural unit with acid-dissociable groups is represented by the following formula (2); 4. (In the formula (2), R7 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; R8 is a monovalent hydrocarbon group with 1 to 20 carbon atoms; R9 and R10 are respectively independently monovalent chain hydrocarbon groups with 1 to 10 carbon atoms or monovalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms, or represent divalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms formed by the combination of these groups and together with the carbon atoms to which they are bonded).

5. The radiosensitive linear resin composition as described in claim 1 or claim 2, further comprising a high-fluorine-content resin, wherein the high-fluorine-content resin has a fluorine atom content greater than that of the resin on a mass basis.

6. A method for forming a pattern, comprising: The step of directly or indirectly coating a photosensitive linear resin composition as described in any one of claims 1 to 5 onto a substrate to form a resist film; The steps of exposing the resist film; and developing the exposed resist film using a developing solution.